4 # "Mike had an infinite amount to do and a negative amount of time in which
5 # to do it." - Before and After
8 # The following hash values are used:
9 # value: unsigned int with actual value (as a Math::BigInt::Calc or similiar)
10 # sign : +,-,NaN,+inf,-inf
13 # _f : flags, used by MBF to flag parts of a float as untouchable
15 # Remember not to take shortcuts ala $xs = $x->{value}; $CALC->foo($xs); since
16 # underlying lib might change the reference!
18 my $class = "Math::BigInt";
24 @EXPORT_OK = qw(objectify bgcd blcm);
26 # _trap_inf and _trap_nan are internal and should never be accessed from the
28 use vars qw/$round_mode $accuracy $precision $div_scale $rnd_mode
29 $upgrade $downgrade $_trap_nan $_trap_inf/;
32 # Inside overload, the first arg is always an object. If the original code had
33 # it reversed (like $x = 2 * $y), then the third paramater is true.
34 # In some cases (like add, $x = $x + 2 is the same as $x = 2 + $x) this makes
35 # no difference, but in some cases it does.
37 # For overloaded ops with only one argument we simple use $_[0]->copy() to
38 # preserve the argument.
40 # Thus inheritance of overload operators becomes possible and transparent for
41 # our subclasses without the need to repeat the entire overload section there.
44 '=' => sub { $_[0]->copy(); },
46 # some shortcuts for speed (assumes that reversed order of arguments is routed
47 # to normal '+' and we thus can always modify first arg. If this is changed,
48 # this breaks and must be adjusted.)
49 '+=' => sub { $_[0]->badd($_[1]); },
50 '-=' => sub { $_[0]->bsub($_[1]); },
51 '*=' => sub { $_[0]->bmul($_[1]); },
52 '/=' => sub { scalar $_[0]->bdiv($_[1]); },
53 '%=' => sub { $_[0]->bmod($_[1]); },
54 '^=' => sub { $_[0]->bxor($_[1]); },
55 '&=' => sub { $_[0]->band($_[1]); },
56 '|=' => sub { $_[0]->bior($_[1]); },
58 '**=' => sub { $_[0]->bpow($_[1]); },
59 '<<=' => sub { $_[0]->blsft($_[1]); },
60 '>>=' => sub { $_[0]->brsft($_[1]); },
62 # not supported by Perl yet
63 '..' => \&_pointpoint,
65 '<=>' => sub { my $rc = $_[2] ?
66 ref($_[0])->bcmp($_[1],$_[0]) :
68 $rc = 1 unless defined $rc;
71 # we need '>=' to get things like "1 >= NaN" right:
72 '>=' => sub { my $rc = $_[2] ?
73 ref($_[0])->bcmp($_[1],$_[0]) :
75 # if there was a NaN involved, return false
76 return '' unless defined $rc;
81 "$_[1]" cmp $_[0]->bstr() :
82 $_[0]->bstr() cmp "$_[1]" },
84 'cos' => sub { $_[0]->copy->bcos(); },
85 'sin' => sub { $_[0]->copy->bsin(); },
86 'atan2' => sub { $_[2] ?
87 ref($_[0])->new($_[1])->batan2($_[0]) :
88 $_[0]->copy()->batan2($_[1]) },
90 # are not yet overloadable
91 #'hex' => sub { print "hex"; $_[0]; },
92 #'oct' => sub { print "oct"; $_[0]; },
94 # log(N) is log(N, e), where e is Euler's number
95 'log' => sub { $_[0]->copy()->blog($_[1], undef); },
96 'exp' => sub { $_[0]->copy()->bexp($_[1]); },
97 'int' => sub { $_[0]->copy(); },
98 'neg' => sub { $_[0]->copy()->bneg(); },
99 'abs' => sub { $_[0]->copy()->babs(); },
100 'sqrt' => sub { $_[0]->copy()->bsqrt(); },
101 '~' => sub { $_[0]->copy()->bnot(); },
103 # for subtract it's a bit tricky to not modify b: b-a => -a+b
104 '-' => sub { my $c = $_[0]->copy; $_[2] ?
105 $c->bneg()->badd( $_[1]) :
107 '+' => sub { $_[0]->copy()->badd($_[1]); },
108 '*' => sub { $_[0]->copy()->bmul($_[1]); },
111 $_[2] ? ref($_[0])->new($_[1])->bdiv($_[0]) : $_[0]->copy->bdiv($_[1]);
114 $_[2] ? ref($_[0])->new($_[1])->bmod($_[0]) : $_[0]->copy->bmod($_[1]);
117 $_[2] ? ref($_[0])->new($_[1])->bpow($_[0]) : $_[0]->copy->bpow($_[1]);
120 $_[2] ? ref($_[0])->new($_[1])->blsft($_[0]) : $_[0]->copy->blsft($_[1]);
123 $_[2] ? ref($_[0])->new($_[1])->brsft($_[0]) : $_[0]->copy->brsft($_[1]);
126 $_[2] ? ref($_[0])->new($_[1])->band($_[0]) : $_[0]->copy->band($_[1]);
129 $_[2] ? ref($_[0])->new($_[1])->bior($_[0]) : $_[0]->copy->bior($_[1]);
132 $_[2] ? ref($_[0])->new($_[1])->bxor($_[0]) : $_[0]->copy->bxor($_[1]);
135 # can modify arg of ++ and --, so avoid a copy() for speed, but don't
136 # use $_[0]->bone(), it would modify $_[0] to be 1!
137 '++' => sub { $_[0]->binc() },
138 '--' => sub { $_[0]->bdec() },
140 # if overloaded, O(1) instead of O(N) and twice as fast for small numbers
142 # this kludge is needed for perl prior 5.6.0 since returning 0 here fails :-/
143 # v5.6.1 dumps on this: return !$_[0]->is_zero() || undef; :-(
145 $t = 1 if !$_[0]->is_zero();
149 # the original qw() does not work with the TIESCALAR below, why?
150 # Order of arguments unsignificant
151 '""' => sub { $_[0]->bstr(); },
152 '0+' => sub { $_[0]->numify(); }
155 ##############################################################################
156 # global constants, flags and accessory
158 # These vars are public, but their direct usage is not recommended, use the
159 # accessor methods instead
161 $round_mode = 'even'; # one of 'even', 'odd', '+inf', '-inf', 'zero', 'trunc' or 'common'
166 $upgrade = undef; # default is no upgrade
167 $downgrade = undef; # default is no downgrade
169 # These are internally, and not to be used from the outside at all
171 $_trap_nan = 0; # are NaNs ok? set w/ config()
172 $_trap_inf = 0; # are infs ok? set w/ config()
173 my $nan = 'NaN'; # constants for easier life
175 my $CALC = 'Math::BigInt::FastCalc'; # module to do the low level math
176 # default is FastCalc.pm
177 my $IMPORT = 0; # was import() called yet?
178 # used to make require work
179 my %WARN; # warn only once for low-level libs
180 my %CAN; # cache for $CALC->can(...)
181 my %CALLBACKS; # callbacks to notify on lib loads
182 my $EMU_LIB = 'Math/BigInt/CalcEmu.pm'; # emulate low-level math
184 ##############################################################################
185 # the old code had $rnd_mode, so we need to support it, too
188 sub TIESCALAR { my ($class) = @_; bless \$round_mode, $class; }
189 sub FETCH { return $round_mode; }
190 sub STORE { $rnd_mode = $_[0]->round_mode($_[1]); }
194 # tie to enable $rnd_mode to work transparently
195 tie $rnd_mode, 'Math::BigInt';
197 # set up some handy alias names
198 *as_int = \&as_number;
199 *is_pos = \&is_positive;
200 *is_neg = \&is_negative;
203 ##############################################################################
208 # make Class->round_mode() work
210 my $class = ref($self) || $self || __PACKAGE__;
214 if ($m !~ /^(even|odd|\+inf|\-inf|zero|trunc|common)$/)
216 require Carp; Carp::croak ("Unknown round mode '$m'");
218 return ${"${class}::round_mode"} = $m;
220 ${"${class}::round_mode"};
226 # make Class->upgrade() work
228 my $class = ref($self) || $self || __PACKAGE__;
229 # need to set new value?
232 return ${"${class}::upgrade"} = $_[0];
234 ${"${class}::upgrade"};
240 # make Class->downgrade() work
242 my $class = ref($self) || $self || __PACKAGE__;
243 # need to set new value?
246 return ${"${class}::downgrade"} = $_[0];
248 ${"${class}::downgrade"};
254 # make Class->div_scale() work
256 my $class = ref($self) || $self || __PACKAGE__;
261 require Carp; Carp::croak ('div_scale must be greater than zero');
263 ${"${class}::div_scale"} = $_[0];
265 ${"${class}::div_scale"};
270 # $x->accuracy($a); ref($x) $a
271 # $x->accuracy(); ref($x)
272 # Class->accuracy(); class
273 # Class->accuracy($a); class $a
276 my $class = ref($x) || $x || __PACKAGE__;
279 # need to set new value?
283 # convert objects to scalars to avoid deep recursion. If object doesn't
284 # have numify(), then hopefully it will have overloading for int() and
285 # boolean test without wandering into a deep recursion path...
286 $a = $a->numify() if ref($a) && $a->can('numify');
290 # also croak on non-numerical
294 Carp::croak ('Argument to accuracy must be greater than zero');
298 require Carp; Carp::croak ('Argument to accuracy must be an integer');
303 # $object->accuracy() or fallback to global
304 $x->bround($a) if $a; # not for undef, 0
305 $x->{_a} = $a; # set/overwrite, even if not rounded
306 delete $x->{_p}; # clear P
307 $a = ${"${class}::accuracy"} unless defined $a; # proper return value
311 ${"${class}::accuracy"} = $a; # set global A
312 ${"${class}::precision"} = undef; # clear global P
314 return $a; # shortcut
318 # $object->accuracy() or fallback to global
319 $a = $x->{_a} if ref($x);
320 # but don't return global undef, when $x's accuracy is 0!
321 $a = ${"${class}::accuracy"} if !defined $a;
327 # $x->precision($p); ref($x) $p
328 # $x->precision(); ref($x)
329 # Class->precision(); class
330 # Class->precision($p); class $p
333 my $class = ref($x) || $x || __PACKAGE__;
339 # convert objects to scalars to avoid deep recursion. If object doesn't
340 # have numify(), then hopefully it will have overloading for int() and
341 # boolean test without wandering into a deep recursion path...
342 $p = $p->numify() if ref($p) && $p->can('numify');
343 if ((defined $p) && (int($p) != $p))
345 require Carp; Carp::croak ('Argument to precision must be an integer');
349 # $object->precision() or fallback to global
350 $x->bfround($p) if $p; # not for undef, 0
351 $x->{_p} = $p; # set/overwrite, even if not rounded
352 delete $x->{_a}; # clear A
353 $p = ${"${class}::precision"} unless defined $p; # proper return value
357 ${"${class}::precision"} = $p; # set global P
358 ${"${class}::accuracy"} = undef; # clear global A
360 return $p; # shortcut
364 # $object->precision() or fallback to global
365 $p = $x->{_p} if ref($x);
366 # but don't return global undef, when $x's precision is 0!
367 $p = ${"${class}::precision"} if !defined $p;
373 # return (or set) configuration data as hash ref
374 my $class = shift || 'Math::BigInt';
377 if (@_ > 1 || (@_ == 1 && (ref($_[0]) eq 'HASH')))
379 # try to set given options as arguments from hash
382 if (ref($args) ne 'HASH')
386 # these values can be "set"
390 upgrade downgrade precision accuracy round_mode div_scale/
393 $set_args->{$key} = $args->{$key} if exists $args->{$key};
394 delete $args->{$key};
399 Carp::croak ("Illegal key(s) '",
400 join("','",keys %$args),"' passed to $class\->config()");
402 foreach my $key (keys %$set_args)
404 if ($key =~ /^trap_(inf|nan)\z/)
406 ${"${class}::_trap_$1"} = ($set_args->{"trap_$1"} ? 1 : 0);
409 # use a call instead of just setting the $variable to check argument
410 $class->$key($set_args->{$key});
414 # now return actual configuration
418 lib_version => ${"${CALC}::VERSION"},
420 trap_nan => ${"${class}::_trap_nan"},
421 trap_inf => ${"${class}::_trap_inf"},
422 version => ${"${class}::VERSION"},
425 upgrade downgrade precision accuracy round_mode div_scale
428 $cfg->{$key} = ${"${class}::$key"};
430 if (@_ == 1 && (ref($_[0]) ne 'HASH'))
432 # calls of the style config('lib') return just this value
433 return $cfg->{$_[0]};
440 # select accuracy parameter based on precedence,
441 # used by bround() and bfround(), may return undef for scale (means no op)
442 my ($x,$scale,$mode) = @_;
444 $scale = $x->{_a} unless defined $scale;
449 $scale = ${ $class . '::accuracy' } unless defined $scale;
450 $mode = ${ $class . '::round_mode' } unless defined $mode;
457 # select precision parameter based on precedence,
458 # used by bround() and bfround(), may return undef for scale (means no op)
459 my ($x,$scale,$mode) = @_;
461 $scale = $x->{_p} unless defined $scale;
466 $scale = ${ $class . '::precision' } unless defined $scale;
467 $mode = ${ $class . '::round_mode' } unless defined $mode;
472 ##############################################################################
477 # if two arguments, the first one is the class to "swallow" subclasses
481 sign => $_[1]->{sign},
482 value => $CALC->_copy($_[1]->{value}),
485 $self->{_a} = $_[1]->{_a} if defined $_[1]->{_a};
486 $self->{_p} = $_[1]->{_p} if defined $_[1]->{_p};
491 sign => $_[0]->{sign},
492 value => $CALC->_copy($_[0]->{value}),
495 $self->{_a} = $_[0]->{_a} if defined $_[0]->{_a};
496 $self->{_p} = $_[0]->{_p} if defined $_[0]->{_p};
502 # create a new BigInt object from a string or another BigInt object.
503 # see hash keys documented at top
505 # the argument could be an object, so avoid ||, && etc on it, this would
506 # cause costly overloaded code to be called. The only allowed ops are
509 my ($class,$wanted,$a,$p,$r) = @_;
511 # avoid numify-calls by not using || on $wanted!
512 return $class->bzero($a,$p) if !defined $wanted; # default to 0
513 return $class->copy($wanted,$a,$p,$r)
514 if ref($wanted) && $wanted->isa($class); # MBI or subclass
516 $class->import() if $IMPORT == 0; # make require work
518 my $self = bless {}, $class;
520 # shortcut for "normal" numbers
521 if ((!ref $wanted) && ($wanted =~ /^([+-]?)[1-9][0-9]*\z/))
523 $self->{sign} = $1 || '+';
525 if ($wanted =~ /^[+-]/)
527 # remove sign without touching wanted to make it work with constants
528 my $t = $wanted; $t =~ s/^[+-]//;
529 $self->{value} = $CALC->_new($t);
533 $self->{value} = $CALC->_new($wanted);
536 if ( (defined $a) || (defined $p)
537 || (defined ${"${class}::precision"})
538 || (defined ${"${class}::accuracy"})
541 $self->round($a,$p,$r) unless (@_ == 4 && !defined $a && !defined $p);
546 # handle '+inf', '-inf' first
547 if ($wanted =~ /^[+-]?inf\z/)
549 $self->{sign} = $wanted; # set a default sign for bstr()
550 return $self->binf($wanted);
552 # split str in m mantissa, e exponent, i integer, f fraction, v value, s sign
553 my ($mis,$miv,$mfv,$es,$ev) = _split($wanted);
558 require Carp; Carp::croak("$wanted is not a number in $class");
560 $self->{value} = $CALC->_zero();
561 $self->{sign} = $nan;
566 # _from_hex or _from_bin
567 $self->{value} = $mis->{value};
568 $self->{sign} = $mis->{sign};
569 return $self; # throw away $mis
571 # make integer from mantissa by adjusting exp, then convert to bigint
572 $self->{sign} = $$mis; # store sign
573 $self->{value} = $CALC->_zero(); # for all the NaN cases
574 my $e = int("$$es$$ev"); # exponent (avoid recursion)
577 my $diff = $e - CORE::length($$mfv);
578 if ($diff < 0) # Not integer
582 require Carp; Carp::croak("$wanted not an integer in $class");
585 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
586 $self->{sign} = $nan;
590 # adjust fraction and add it to value
591 #print "diff > 0 $$miv\n";
592 $$miv = $$miv . ($$mfv . '0' x $diff);
597 if ($$mfv ne '') # e <= 0
599 # fraction and negative/zero E => NOI
602 require Carp; Carp::croak("$wanted not an integer in $class");
604 #print "NOI 2 \$\$mfv '$$mfv'\n";
605 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
606 $self->{sign} = $nan;
610 # xE-y, and empty mfv
613 if ($$miv !~ s/0{$e}$//) # can strip so many zero's?
617 require Carp; Carp::croak("$wanted not an integer in $class");
620 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
621 $self->{sign} = $nan;
625 $self->{sign} = '+' if $$miv eq '0'; # normalize -0 => +0
626 $self->{value} = $CALC->_new($$miv) if $self->{sign} =~ /^[+-]$/;
627 # if any of the globals is set, use them to round and store them inside $self
628 # do not round for new($x,undef,undef) since that is used by MBF to signal
630 $self->round($a,$p,$r) unless @_ == 4 && !defined $a && !defined $p;
636 # create a bigint 'NaN', if given a BigInt, set it to 'NaN'
638 $self = $class if !defined $self;
641 my $c = $self; $self = {}; bless $self, $c;
644 if (${"${class}::_trap_nan"})
647 Carp::croak ("Tried to set $self to NaN in $class\::bnan()");
649 $self->import() if $IMPORT == 0; # make require work
650 return if $self->modify('bnan');
651 if ($self->can('_bnan'))
653 # use subclass to initialize
658 # otherwise do our own thing
659 $self->{value} = $CALC->_zero();
661 $self->{sign} = $nan;
662 delete $self->{_a}; delete $self->{_p}; # rounding NaN is silly
668 # create a bigint '+-inf', if given a BigInt, set it to '+-inf'
669 # the sign is either '+', or if given, used from there
671 my $sign = shift; $sign = '+' if !defined $sign || $sign !~ /^-(inf)?$/;
672 $self = $class if !defined $self;
675 my $c = $self; $self = {}; bless $self, $c;
678 if (${"${class}::_trap_inf"})
681 Carp::croak ("Tried to set $self to +-inf in $class\::binf()");
683 $self->import() if $IMPORT == 0; # make require work
684 return if $self->modify('binf');
685 if ($self->can('_binf'))
687 # use subclass to initialize
692 # otherwise do our own thing
693 $self->{value} = $CALC->_zero();
695 $sign = $sign . 'inf' if $sign !~ /inf$/; # - => -inf
696 $self->{sign} = $sign;
697 ($self->{_a},$self->{_p}) = @_; # take over requested rounding
703 # create a bigint '+0', if given a BigInt, set it to 0
705 $self = __PACKAGE__ if !defined $self;
709 my $c = $self; $self = {}; bless $self, $c;
711 $self->import() if $IMPORT == 0; # make require work
712 return if $self->modify('bzero');
714 if ($self->can('_bzero'))
716 # use subclass to initialize
721 # otherwise do our own thing
722 $self->{value} = $CALC->_zero();
729 # call like: $x->bzero($a,$p,$r,$y);
730 ($self,$self->{_a},$self->{_p}) = $self->_find_round_parameters(@_);
735 if ( (!defined $self->{_a}) || (defined $_[0] && $_[0] > $self->{_a}));
737 if ( (!defined $self->{_p}) || (defined $_[1] && $_[1] > $self->{_p}));
745 # create a bigint '+1' (or -1 if given sign '-'),
746 # if given a BigInt, set it to +1 or -1, respectively
748 my $sign = shift; $sign = '+' if !defined $sign || $sign ne '-';
749 $self = $class if !defined $self;
753 my $c = $self; $self = {}; bless $self, $c;
755 $self->import() if $IMPORT == 0; # make require work
756 return if $self->modify('bone');
758 if ($self->can('_bone'))
760 # use subclass to initialize
765 # otherwise do our own thing
766 $self->{value} = $CALC->_one();
768 $self->{sign} = $sign;
773 # call like: $x->bone($sign,$a,$p,$r,$y);
774 ($self,$self->{_a},$self->{_p}) = $self->_find_round_parameters(@_);
778 # call like: $x->bone($sign,$a,$p,$r);
780 if ( (!defined $self->{_a}) || (defined $_[0] && $_[0] > $self->{_a}));
782 if ( (!defined $self->{_p}) || (defined $_[1] && $_[1] > $self->{_p}));
788 ##############################################################################
789 # string conversation
793 # (ref to BFLOAT or num_str ) return num_str
794 # Convert number from internal format to scientific string format.
795 # internal format is always normalized (no leading zeros, "-0E0" => "+0E0")
796 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
798 if ($x->{sign} !~ /^[+-]$/)
800 return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
803 my ($m,$e) = $x->parts();
804 #$m->bstr() . 'e+' . $e->bstr(); # e can only be positive in BigInt
805 # 'e+' because E can only be positive in BigInt
806 $m->bstr() . 'e+' . $CALC->_str($e->{value});
811 # make a string from bigint object
812 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
814 if ($x->{sign} !~ /^[+-]$/)
816 return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
819 my $es = ''; $es = $x->{sign} if $x->{sign} eq '-';
820 $es.$CALC->_str($x->{value});
825 # Make a "normal" scalar from a BigInt object
826 my $x = shift; $x = $class->new($x) unless ref $x;
828 return $x->bstr() if $x->{sign} !~ /^[+-]$/;
829 my $num = $CALC->_num($x->{value});
830 return -$num if $x->{sign} eq '-';
834 ##############################################################################
835 # public stuff (usually prefixed with "b")
839 # return the sign of the number: +/-/-inf/+inf/NaN
840 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
845 sub _find_round_parameters
847 # After any operation or when calling round(), the result is rounded by
848 # regarding the A & P from arguments, local parameters, or globals.
850 # !!!!!!! If you change this, remember to change round(), too! !!!!!!!!!!
852 # This procedure finds the round parameters, but it is for speed reasons
853 # duplicated in round. Otherwise, it is tested by the testsuite and used
856 # returns ($self) or ($self,$a,$p,$r) - sets $self to NaN of both A and P
857 # were requested/defined (locally or globally or both)
859 my ($self,$a,$p,$r,@args) = @_;
860 # $a accuracy, if given by caller
861 # $p precision, if given by caller
862 # $r round_mode, if given by caller
863 # @args all 'other' arguments (0 for unary, 1 for binary ops)
865 my $c = ref($self); # find out class of argument(s)
868 # convert to normal scalar for speed and correctness in inner parts
869 $a = $a->can('numify') ? $a->numify() : "$a" if defined $a && ref($a);
870 $p = $p->can('numify') ? $p->numify() : "$p" if defined $p && ref($p);
872 # now pick $a or $p, but only if we have got "arguments"
875 foreach ($self,@args)
877 # take the defined one, or if both defined, the one that is smaller
878 $a = $_->{_a} if (defined $_->{_a}) && (!defined $a || $_->{_a} < $a);
883 # even if $a is defined, take $p, to signal error for both defined
884 foreach ($self,@args)
886 # take the defined one, or if both defined, the one that is bigger
888 $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} > $p);
891 # if still none defined, use globals (#2)
892 $a = ${"$c\::accuracy"} unless defined $a;
893 $p = ${"$c\::precision"} unless defined $p;
895 # A == 0 is useless, so undef it to signal no rounding
896 $a = undef if defined $a && $a == 0;
899 return ($self) unless defined $a || defined $p; # early out
901 # set A and set P is an fatal error
902 return ($self->bnan()) if defined $a && defined $p; # error
904 $r = ${"$c\::round_mode"} unless defined $r;
905 if ($r !~ /^(even|odd|\+inf|\-inf|zero|trunc|common)$/)
907 require Carp; Carp::croak ("Unknown round mode '$r'");
915 # Round $self according to given parameters, or given second argument's
916 # parameters or global defaults
918 # for speed reasons, _find_round_parameters is embeded here:
920 my ($self,$a,$p,$r,@args) = @_;
921 # $a accuracy, if given by caller
922 # $p precision, if given by caller
923 # $r round_mode, if given by caller
924 # @args all 'other' arguments (0 for unary, 1 for binary ops)
926 my $c = ref($self); # find out class of argument(s)
929 # now pick $a or $p, but only if we have got "arguments"
932 foreach ($self,@args)
934 # take the defined one, or if both defined, the one that is smaller
935 $a = $_->{_a} if (defined $_->{_a}) && (!defined $a || $_->{_a} < $a);
940 # even if $a is defined, take $p, to signal error for both defined
941 foreach ($self,@args)
943 # take the defined one, or if both defined, the one that is bigger
945 $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} > $p);
948 # if still none defined, use globals (#2)
949 $a = ${"$c\::accuracy"} unless defined $a;
950 $p = ${"$c\::precision"} unless defined $p;
952 # A == 0 is useless, so undef it to signal no rounding
953 $a = undef if defined $a && $a == 0;
956 return $self unless defined $a || defined $p; # early out
958 # set A and set P is an fatal error
959 return $self->bnan() if defined $a && defined $p;
961 $r = ${"$c\::round_mode"} unless defined $r;
962 if ($r !~ /^(even|odd|\+inf|\-inf|zero|trunc|common)$/)
964 require Carp; Carp::croak ("Unknown round mode '$r'");
967 # now round, by calling either fround or ffround:
970 $self->bround($a,$r) if !defined $self->{_a} || $self->{_a} >= $a;
972 else # both can't be undefined due to early out
974 $self->bfround($p,$r) if !defined $self->{_p} || $self->{_p} <= $p;
976 # bround() or bfround() already callled bnorm() if nec.
982 # (numstr or BINT) return BINT
983 # Normalize number -- no-op here
984 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
990 # (BINT or num_str) return BINT
991 # make number absolute, or return absolute BINT from string
992 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
994 return $x if $x->modify('babs');
995 # post-normalized abs for internal use (does nothing for NaN)
996 $x->{sign} =~ s/^-/+/;
1002 # (BINT or num_str) return BINT
1003 # negate number or make a negated number from string
1004 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1006 return $x if $x->modify('bneg');
1008 # for +0 dont negate (to have always normalized +0). Does nothing for 'NaN'
1009 $x->{sign} =~ tr/+-/-+/ unless ($x->{sign} eq '+' && $CALC->_is_zero($x->{value}));
1015 # Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort)
1016 # (BINT or num_str, BINT or num_str) return cond_code
1019 my ($self,$x,$y) = (ref($_[0]),@_);
1021 # objectify is costly, so avoid it
1022 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1024 ($self,$x,$y) = objectify(2,@_);
1027 return $upgrade->bcmp($x,$y) if defined $upgrade &&
1028 ((!$x->isa($self)) || (!$y->isa($self)));
1030 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1032 # handle +-inf and NaN
1033 return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1034 return 0 if $x->{sign} eq $y->{sign} && $x->{sign} =~ /^[+-]inf$/;
1035 return +1 if $x->{sign} eq '+inf';
1036 return -1 if $x->{sign} eq '-inf';
1037 return -1 if $y->{sign} eq '+inf';
1040 # check sign for speed first
1041 return 1 if $x->{sign} eq '+' && $y->{sign} eq '-'; # does also 0 <=> -y
1042 return -1 if $x->{sign} eq '-' && $y->{sign} eq '+'; # does also -x <=> 0
1044 # have same sign, so compare absolute values. Don't make tests for zero here
1045 # because it's actually slower than testin in Calc (especially w/ Pari et al)
1047 # post-normalized compare for internal use (honors signs)
1048 if ($x->{sign} eq '+')
1050 # $x and $y both > 0
1051 return $CALC->_acmp($x->{value},$y->{value});
1055 $CALC->_acmp($y->{value},$x->{value}); # swaped acmp (lib returns 0,1,-1)
1060 # Compares 2 values, ignoring their signs.
1061 # Returns one of undef, <0, =0, >0. (suitable for sort)
1062 # (BINT, BINT) return cond_code
1065 my ($self,$x,$y) = (ref($_[0]),@_);
1066 # objectify is costly, so avoid it
1067 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1069 ($self,$x,$y) = objectify(2,@_);
1072 return $upgrade->bacmp($x,$y) if defined $upgrade &&
1073 ((!$x->isa($self)) || (!$y->isa($self)));
1075 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1077 # handle +-inf and NaN
1078 return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1079 return 0 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} =~ /^[+-]inf$/;
1080 return 1 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} !~ /^[+-]inf$/;
1083 $CALC->_acmp($x->{value},$y->{value}); # lib does only 0,1,-1
1088 # add second arg (BINT or string) to first (BINT) (modifies first)
1089 # return result as BINT
1092 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1093 # objectify is costly, so avoid it
1094 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1096 ($self,$x,$y,@r) = objectify(2,@_);
1099 return $x if $x->modify('badd');
1100 return $upgrade->badd($upgrade->new($x),$upgrade->new($y),@r) if defined $upgrade &&
1101 ((!$x->isa($self)) || (!$y->isa($self)));
1103 $r[3] = $y; # no push!
1104 # inf and NaN handling
1105 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1108 return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1110 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1112 # +inf++inf or -inf+-inf => same, rest is NaN
1113 return $x if $x->{sign} eq $y->{sign};
1116 # +-inf + something => +inf
1117 # something +-inf => +-inf
1118 $x->{sign} = $y->{sign}, return $x if $y->{sign} =~ /^[+-]inf$/;
1122 my ($sx, $sy) = ( $x->{sign}, $y->{sign} ); # get signs
1126 $x->{value} = $CALC->_add($x->{value},$y->{value}); # same sign, abs add
1130 my $a = $CALC->_acmp ($y->{value},$x->{value}); # absolute compare
1133 $x->{value} = $CALC->_sub($y->{value},$x->{value},1); # abs sub w/ swap
1138 # speedup, if equal, set result to 0
1139 $x->{value} = $CALC->_zero();
1144 $x->{value} = $CALC->_sub($x->{value}, $y->{value}); # abs sub
1152 # (BINT or num_str, BINT or num_str) return BINT
1153 # subtract second arg from first, modify first
1156 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1158 # objectify is costly, so avoid it
1159 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1161 ($self,$x,$y,@r) = objectify(2,@_);
1164 return $x if $x->modify('bsub');
1166 return $upgrade->new($x)->bsub($upgrade->new($y),@r) if defined $upgrade &&
1167 ((!$x->isa($self)) || (!$y->isa($self)));
1169 return $x->round(@r) if $y->is_zero();
1171 # To correctly handle the lone special case $x->bsub($x), we note the sign
1172 # of $x, then flip the sign from $y, and if the sign of $x did change, too,
1173 # then we caught the special case:
1174 my $xsign = $x->{sign};
1175 $y->{sign} =~ tr/+\-/-+/; # does nothing for NaN
1176 if ($xsign ne $x->{sign})
1178 # special case of $x->bsub($x) results in 0
1179 return $x->bzero(@r) if $xsign =~ /^[+-]$/;
1180 return $x->bnan(); # NaN, -inf, +inf
1182 $x->badd($y,@r); # badd does not leave internal zeros
1183 $y->{sign} =~ tr/+\-/-+/; # refix $y (does nothing for NaN)
1184 $x; # already rounded by badd() or no round nec.
1189 # increment arg by one
1190 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1191 return $x if $x->modify('binc');
1193 if ($x->{sign} eq '+')
1195 $x->{value} = $CALC->_inc($x->{value});
1196 return $x->round($a,$p,$r);
1198 elsif ($x->{sign} eq '-')
1200 $x->{value} = $CALC->_dec($x->{value});
1201 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # -1 +1 => -0 => +0
1202 return $x->round($a,$p,$r);
1204 # inf, nan handling etc
1205 $x->badd($self->bone(),$a,$p,$r); # badd does round
1210 # decrement arg by one
1211 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1212 return $x if $x->modify('bdec');
1214 if ($x->{sign} eq '-')
1217 $x->{value} = $CALC->_inc($x->{value});
1221 return $x->badd($self->bone('-'),@r) unless $x->{sign} eq '+'; # inf or NaN
1223 if ($CALC->_is_zero($x->{value}))
1226 $x->{value} = $CALC->_one(); $x->{sign} = '-'; # 0 => -1
1231 $x->{value} = $CALC->_dec($x->{value});
1239 # calculate $x = $a ** $base + $b and return $a (e.g. the log() to base
1243 my ($self,$x,$base,@r) = (undef,@_);
1244 # objectify is costly, so avoid it
1245 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1247 ($self,$x,$base,@r) = objectify(1,ref($x),@_);
1250 return $x if $x->modify('blog');
1252 $base = $self->new($base) if defined $base && !ref $base;
1254 # inf, -inf, NaN, <0 => NaN
1256 if $x->{sign} ne '+' || (defined $base && $base->{sign} ne '+');
1258 return $upgrade->blog($upgrade->new($x),$base,@r) if
1261 # fix for bug #24969:
1262 # the default base is e (Euler's number) which is not an integer
1265 require Math::BigFloat;
1266 my $u = Math::BigFloat->blog(Math::BigFloat->new($x))->as_int();
1267 # modify $x in place
1268 $x->{value} = $u->{value};
1269 $x->{sign} = $u->{sign};
1273 my ($rc,$exact) = $CALC->_log_int($x->{value},$base->{value});
1274 return $x->bnan() unless defined $rc; # not possible to take log?
1281 # Calculate n over k (binomial coefficient or "choose" function) as integer.
1283 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1285 # objectify is costly, so avoid it
1286 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1288 ($self,$x,$y,@r) = objectify(2,@_);
1291 return $x if $x->modify('bnok');
1292 return $x->bnan() if $x->{sign} eq 'NaN' || $y->{sign} eq 'NaN';
1293 return $x->binf() if $x->{sign} eq '+inf';
1295 # k > n or k < 0 => 0
1296 my $cmp = $x->bacmp($y);
1297 return $x->bzero() if $cmp < 0 || $y->{sign} =~ /^-/;
1299 return $x->bone(@r) if $cmp == 0;
1301 if ($CALC->can('_nok'))
1303 $x->{value} = $CALC->_nok($x->{value},$y->{value});
1307 # ( 7 ) 7! 7*6*5 * 4*3*2*1 7 * 6 * 5
1308 # ( - ) = --------- = --------------- = ---------
1309 # ( 3 ) 3! (7-3)! 3*2*1 * 4*3*2*1 3 * 2 * 1
1311 # compute n - k + 2 (so we start with 5 in the example above)
1316 my $r = $z->copy(); $z->binc();
1317 my $d = $self->new(2);
1318 while ($z->bacmp($x) <= 0) # f < x ?
1320 $r->bmul($z); $r->bdiv($d);
1321 $z->binc(); $d->binc();
1323 $x->{value} = $r->{value}; $x->{sign} = '+';
1325 else { $x->bone(); }
1332 # Calculate e ** $x (Euler's number to the power of X), truncated to
1334 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1335 return $x if $x->modify('bexp');
1337 # inf, -inf, NaN, <0 => NaN
1338 return $x->bnan() if $x->{sign} eq 'NaN';
1339 return $x->bone() if $x->is_zero();
1340 return $x if $x->{sign} eq '+inf';
1341 return $x->bzero() if $x->{sign} eq '-inf';
1345 # run through Math::BigFloat unless told otherwise
1346 require Math::BigFloat unless defined $upgrade;
1347 local $upgrade = 'Math::BigFloat' unless defined $upgrade;
1348 # calculate result, truncate it to integer
1349 $u = $upgrade->bexp($upgrade->new($x),@r);
1352 if (!defined $upgrade)
1355 # modify $x in place
1356 $x->{value} = $u->{value};
1364 # (BINT or num_str, BINT or num_str) return BINT
1365 # does not modify arguments, but returns new object
1366 # Lowest Common Multiplicator
1368 my $y = shift; my ($x);
1375 $x = $class->new($y);
1380 my $y = shift; $y = $self->new($y) if !ref ($y);
1388 # (BINT or num_str, BINT or num_str) return BINT
1389 # does not modify arguments, but returns new object
1390 # GCD -- Euclids algorithm, variant C (Knuth Vol 3, pg 341 ff)
1393 $y = $class->new($y) if !ref($y);
1395 my $x = $y->copy()->babs(); # keep arguments
1396 return $x->bnan() if $x->{sign} !~ /^[+-]$/; # x NaN?
1400 $y = shift; $y = $self->new($y) if !ref($y);
1401 return $x->bnan() if $y->{sign} !~ /^[+-]$/; # y NaN?
1402 $x->{value} = $CALC->_gcd($x->{value},$y->{value});
1403 last if $CALC->_is_one($x->{value});
1410 # (num_str or BINT) return BINT
1411 # represent ~x as twos-complement number
1412 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1413 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1415 return $x if $x->modify('bnot');
1416 $x->binc()->bneg(); # binc already does round
1419 ##############################################################################
1420 # is_foo test routines
1421 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1425 # return true if arg (BINT or num_str) is zero (array '+', '0')
1426 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1428 return 0 if $x->{sign} !~ /^\+$/; # -, NaN & +-inf aren't
1429 $CALC->_is_zero($x->{value});
1434 # return true if arg (BINT or num_str) is NaN
1435 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1437 $x->{sign} eq $nan ? 1 : 0;
1442 # return true if arg (BINT or num_str) is +-inf
1443 my ($self,$x,$sign) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1447 $sign = '[+-]inf' if $sign eq ''; # +- doesn't matter, only that's inf
1448 $sign = "[$1]inf" if $sign =~ /^([+-])(inf)?$/; # extract '+' or '-'
1449 return $x->{sign} =~ /^$sign$/ ? 1 : 0;
1451 $x->{sign} =~ /^[+-]inf$/ ? 1 : 0; # only +-inf is infinity
1456 # return true if arg (BINT or num_str) is +1, or -1 if sign is given
1457 my ($self,$x,$sign) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1459 $sign = '+' if !defined $sign || $sign ne '-';
1461 return 0 if $x->{sign} ne $sign; # -1 != +1, NaN, +-inf aren't either
1462 $CALC->_is_one($x->{value});
1467 # return true when arg (BINT or num_str) is odd, false for even
1468 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1470 return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
1471 $CALC->_is_odd($x->{value});
1476 # return true when arg (BINT or num_str) is even, false for odd
1477 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1479 return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
1480 $CALC->_is_even($x->{value});
1485 # return true when arg (BINT or num_str) is positive (>= 0)
1486 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1488 return 1 if $x->{sign} eq '+inf'; # +inf is positive
1490 # 0+ is neither positive nor negative
1491 ($x->{sign} eq '+' && !$x->is_zero()) ? 1 : 0;
1496 # return true when arg (BINT or num_str) is negative (< 0)
1497 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1499 $x->{sign} =~ /^-/ ? 1 : 0; # -inf is negative, but NaN is not
1504 # return true when arg (BINT or num_str) is an integer
1505 # always true for BigInt, but different for BigFloats
1506 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1508 $x->{sign} =~ /^[+-]$/ ? 1 : 0; # inf/-inf/NaN aren't
1511 ###############################################################################
1515 # multiply the first number by the second number
1516 # (BINT or num_str, BINT or num_str) return BINT
1519 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1520 # objectify is costly, so avoid it
1521 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1523 ($self,$x,$y,@r) = objectify(2,@_);
1526 return $x if $x->modify('bmul');
1528 return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1531 if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
1533 return $x->bnan() if $x->is_zero() || $y->is_zero();
1534 # result will always be +-inf:
1535 # +inf * +/+inf => +inf, -inf * -/-inf => +inf
1536 # +inf * -/-inf => -inf, -inf * +/+inf => -inf
1537 return $x->binf() if ($x->{sign} =~ /^\+/ && $y->{sign} =~ /^\+/);
1538 return $x->binf() if ($x->{sign} =~ /^-/ && $y->{sign} =~ /^-/);
1539 return $x->binf('-');
1542 return $upgrade->bmul($x,$upgrade->new($y),@r)
1543 if defined $upgrade && !$y->isa($self);
1545 $r[3] = $y; # no push here
1547 $x->{sign} = $x->{sign} eq $y->{sign} ? '+' : '-'; # +1 * +1 or -1 * -1 => +
1549 $x->{value} = $CALC->_mul($x->{value},$y->{value}); # do actual math
1550 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # no -0
1557 # multiply two numbers and then add the third to the result
1558 # (BINT or num_str, BINT or num_str, BINT or num_str) return BINT
1561 my ($self,$x,$y,$z,@r) = (ref($_[0]),@_);
1562 # objectify is costly, so avoid it
1563 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1565 ($self,$x,$y,$z,@r) = objectify(3,@_);
1568 return $x if $x->modify('bmuladd');
1570 return $x->bnan() if ($x->{sign} eq $nan) ||
1571 ($y->{sign} eq $nan) ||
1572 ($z->{sign} eq $nan);
1574 # inf handling of x and y
1575 if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
1577 return $x->bnan() if $x->is_zero() || $y->is_zero();
1578 # result will always be +-inf:
1579 # +inf * +/+inf => +inf, -inf * -/-inf => +inf
1580 # +inf * -/-inf => -inf, -inf * +/+inf => -inf
1581 return $x->binf() if ($x->{sign} =~ /^\+/ && $y->{sign} =~ /^\+/);
1582 return $x->binf() if ($x->{sign} =~ /^-/ && $y->{sign} =~ /^-/);
1583 return $x->binf('-');
1585 # inf handling x*y and z
1586 if (($z->{sign} =~ /^[+-]inf$/))
1588 # something +-inf => +-inf
1589 $x->{sign} = $z->{sign}, return $x if $z->{sign} =~ /^[+-]inf$/;
1592 return $upgrade->bmuladd($x,$upgrade->new($y),$upgrade->new($z),@r)
1593 if defined $upgrade && (!$y->isa($self) || !$z->isa($self) || !$x->isa($self));
1595 # TODO: what if $y and $z have A or P set?
1596 $r[3] = $z; # no push here
1598 $x->{sign} = $x->{sign} eq $y->{sign} ? '+' : '-'; # +1 * +1 or -1 * -1 => +
1600 $x->{value} = $CALC->_mul($x->{value},$y->{value}); # do actual math
1601 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # no -0
1603 my ($sx, $sz) = ( $x->{sign}, $z->{sign} ); # get signs
1607 $x->{value} = $CALC->_add($x->{value},$z->{value}); # same sign, abs add
1611 my $a = $CALC->_acmp ($z->{value},$x->{value}); # absolute compare
1614 $x->{value} = $CALC->_sub($z->{value},$x->{value},1); # abs sub w/ swap
1619 # speedup, if equal, set result to 0
1620 $x->{value} = $CALC->_zero();
1625 $x->{value} = $CALC->_sub($x->{value}, $z->{value}); # abs sub
1633 # helper function that handles +-inf cases for bdiv()/bmod() to reuse code
1634 my ($self,$x,$y) = @_;
1636 # NaN if x == NaN or y == NaN or x==y==0
1637 return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan()
1638 if (($x->is_nan() || $y->is_nan()) ||
1639 ($x->is_zero() && $y->is_zero()));
1641 # +-inf / +-inf == NaN, reminder also NaN
1642 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1644 return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan();
1646 # x / +-inf => 0, remainder x (works even if x == 0)
1647 if ($y->{sign} =~ /^[+-]inf$/)
1649 my $t = $x->copy(); # bzero clobbers up $x
1650 return wantarray ? ($x->bzero(),$t) : $x->bzero()
1653 # 5 / 0 => +inf, -6 / 0 => -inf
1654 # +inf / 0 = inf, inf, and -inf / 0 => -inf, -inf
1655 # exception: -8 / 0 has remainder -8, not 8
1656 # exception: -inf / 0 has remainder -inf, not inf
1659 # +-inf / 0 => special case for -inf
1660 return wantarray ? ($x,$x->copy()) : $x if $x->is_inf();
1661 if (!$x->is_zero() && !$x->is_inf())
1663 my $t = $x->copy(); # binf clobbers up $x
1665 ($x->binf($x->{sign}),$t) : $x->binf($x->{sign})
1669 # last case: +-inf / ordinary number
1671 $sign = '-inf' if substr($x->{sign},0,1) ne $y->{sign};
1673 return wantarray ? ($x,$self->bzero()) : $x;
1678 # (dividend: BINT or num_str, divisor: BINT or num_str) return
1679 # (BINT,BINT) (quo,rem) or BINT (only rem)
1682 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1683 # objectify is costly, so avoid it
1684 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1686 ($self,$x,$y,@r) = objectify(2,@_);
1689 return $x if $x->modify('bdiv');
1691 return $self->_div_inf($x,$y)
1692 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero());
1694 return $upgrade->bdiv($upgrade->new($x),$upgrade->new($y),@r)
1695 if defined $upgrade;
1697 $r[3] = $y; # no push!
1699 # calc new sign and in case $y == +/- 1, return $x
1700 my $xsign = $x->{sign}; # keep
1701 $x->{sign} = ($x->{sign} ne $y->{sign} ? '-' : '+');
1705 my $rem = $self->bzero();
1706 ($x->{value},$rem->{value}) = $CALC->_div($x->{value},$y->{value});
1707 $x->{sign} = '+' if $CALC->_is_zero($x->{value});
1708 $rem->{_a} = $x->{_a};
1709 $rem->{_p} = $x->{_p};
1711 if (! $CALC->_is_zero($rem->{value}))
1713 $rem->{sign} = $y->{sign};
1714 $rem = $y->copy()->bsub($rem) if $xsign ne $y->{sign}; # one of them '-'
1718 $rem->{sign} = '+'; # dont leave -0
1724 $x->{value} = $CALC->_div($x->{value},$y->{value});
1725 $x->{sign} = '+' if $CALC->_is_zero($x->{value});
1730 ###############################################################################
1735 # modulus (or remainder)
1736 # (BINT or num_str, BINT or num_str) return BINT
1739 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1740 # objectify is costly, so avoid it
1741 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1743 ($self,$x,$y,@r) = objectify(2,@_);
1746 return $x if $x->modify('bmod');
1747 $r[3] = $y; # no push!
1748 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero())
1750 my ($d,$r) = $self->_div_inf($x,$y);
1751 $x->{sign} = $r->{sign};
1752 $x->{value} = $r->{value};
1753 return $x->round(@r);
1756 # calc new sign and in case $y == +/- 1, return $x
1757 $x->{value} = $CALC->_mod($x->{value},$y->{value});
1758 if (!$CALC->_is_zero($x->{value}))
1760 $x->{value} = $CALC->_sub($y->{value},$x->{value},1) # $y-$x
1761 if ($x->{sign} ne $y->{sign});
1762 $x->{sign} = $y->{sign};
1766 $x->{sign} = '+'; # dont leave -0
1773 # Modular inverse. given a number which is (hopefully) relatively
1774 # prime to the modulus, calculate its inverse using Euclid's
1775 # alogrithm. If the number is not relatively prime to the modulus
1776 # (i.e. their gcd is not one) then NaN is returned.
1779 my ($self,$x,$y,@r) = (undef,@_);
1780 # objectify is costly, so avoid it
1781 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1783 ($self,$x,$y,@r) = objectify(2,@_);
1786 return $x if $x->modify('bmodinv');
1789 if ($y->{sign} ne '+' # -, NaN, +inf, -inf
1790 || $x->is_zero() # or num == 0
1791 || $x->{sign} !~ /^[+-]$/ # or num NaN, inf, -inf
1794 # put least residue into $x if $x was negative, and thus make it positive
1795 $x->bmod($y) if $x->{sign} eq '-';
1798 ($x->{value},$sign) = $CALC->_modinv($x->{value},$y->{value});
1799 return $x->bnan() if !defined $x->{value}; # in case no GCD found
1800 return $x if !defined $sign; # already real result
1801 $x->{sign} = $sign; # flip/flop see below
1802 $x->bmod($y); # calc real result
1808 # takes a very large number to a very large exponent in a given very
1809 # large modulus, quickly, thanks to binary exponentation. Supports
1810 # negative exponents.
1811 my ($self,$num,$exp,$mod,@r) = objectify(3,@_);
1813 return $num if $num->modify('bmodpow');
1815 # check modulus for valid values
1816 return $num->bnan() if ($mod->{sign} ne '+' # NaN, - , -inf, +inf
1817 || $mod->is_zero());
1819 # check exponent for valid values
1820 if ($exp->{sign} =~ /\w/)
1822 # i.e., if it's NaN, +inf, or -inf...
1823 return $num->bnan();
1826 $num->bmodinv ($mod) if ($exp->{sign} eq '-');
1828 # check num for valid values (also NaN if there was no inverse but $exp < 0)
1829 return $num->bnan() if $num->{sign} !~ /^[+-]$/;
1831 # $mod is positive, sign on $exp is ignored, result also positive
1832 $num->{value} = $CALC->_modpow($num->{value},$exp->{value},$mod->{value});
1836 ###############################################################################
1840 # (BINT or num_str, BINT or num_str) return BINT
1841 # compute factorial number from $x, modify $x in place
1842 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1844 return $x if $x->modify('bfac') || $x->{sign} eq '+inf'; # inf => inf
1845 return $x->bnan() if $x->{sign} ne '+'; # NaN, <0 etc => NaN
1847 $x->{value} = $CALC->_fac($x->{value});
1853 # (BINT or num_str, BINT or num_str) return BINT
1854 # compute power of two numbers -- stolen from Knuth Vol 2 pg 233
1855 # modifies first argument
1858 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1859 # objectify is costly, so avoid it
1860 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1862 ($self,$x,$y,@r) = objectify(2,@_);
1865 return $x if $x->modify('bpow');
1867 return $x->bnan() if $x->{sign} eq $nan || $y->{sign} eq $nan;
1870 if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
1872 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1878 if ($x->{sign} =~ /^[+-]inf/)
1881 return $x->bnan() if $y->is_zero();
1882 # -inf ** -1 => 1/inf => 0
1883 return $x->bzero() if $y->is_one('-') && $x->is_negative();
1886 return $x if $x->{sign} eq '+inf';
1888 # -inf ** Y => -inf if Y is odd
1889 return $x if $y->is_odd();
1895 return $x if $x->is_one();
1898 return $x if $x->is_zero() && $y->{sign} =~ /^[+]/;
1901 return $x->binf() if $x->is_zero();
1904 return $x->bnan() if $x->is_one('-') && $y->{sign} =~ /^[-]/;
1907 return $x->bzero() if $x->{sign} eq '-' && $y->{sign} =~ /^[-]/;
1910 return $x->bnan() if $x->{sign} eq '-';
1913 return $x->binf() if $y->{sign} =~ /^[+]/;
1918 return $upgrade->bpow($upgrade->new($x),$y,@r)
1919 if defined $upgrade && (!$y->isa($self) || $y->{sign} eq '-');
1921 $r[3] = $y; # no push!
1923 # cases 0 ** Y, X ** 0, X ** 1, 1 ** Y are handled by Calc or Emu
1926 $new_sign = $y->is_odd() ? '-' : '+' if ($x->{sign} ne '+');
1928 # 0 ** -7 => ( 1 / (0 ** 7)) => 1 / 0 => +inf
1930 if $y->{sign} eq '-' && $x->{sign} eq '+' && $CALC->_is_zero($x->{value});
1931 # 1 ** -y => 1 / (1 ** |y|)
1932 # so do test for negative $y after above's clause
1933 return $x->bnan() if $y->{sign} eq '-' && !$CALC->_is_one($x->{value});
1935 $x->{value} = $CALC->_pow($x->{value},$y->{value});
1936 $x->{sign} = $new_sign;
1937 $x->{sign} = '+' if $CALC->_is_zero($y->{value});
1943 # (BINT or num_str, BINT or num_str) return BINT
1944 # compute x << y, base n, y >= 0
1947 my ($self,$x,$y,$n,@r) = (ref($_[0]),@_);
1948 # objectify is costly, so avoid it
1949 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1951 ($self,$x,$y,$n,@r) = objectify(2,@_);
1954 return $x if $x->modify('blsft');
1955 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1956 return $x->round(@r) if $y->is_zero();
1958 $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
1960 $x->{value} = $CALC->_lsft($x->{value},$y->{value},$n);
1966 # (BINT or num_str, BINT or num_str) return BINT
1967 # compute x >> y, base n, y >= 0
1970 my ($self,$x,$y,$n,@r) = (ref($_[0]),@_);
1971 # objectify is costly, so avoid it
1972 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1974 ($self,$x,$y,$n,@r) = objectify(2,@_);
1977 return $x if $x->modify('brsft');
1978 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1979 return $x->round(@r) if $y->is_zero();
1980 return $x->bzero(@r) if $x->is_zero(); # 0 => 0
1982 $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
1984 # this only works for negative numbers when shifting in base 2
1985 if (($x->{sign} eq '-') && ($n == 2))
1987 return $x->round(@r) if $x->is_one('-'); # -1 => -1
1990 # although this is O(N*N) in calc (as_bin!) it is O(N) in Pari et al
1991 # but perhaps there is a better emulation for two's complement shift...
1992 # if $y != 1, we must simulate it by doing:
1993 # convert to bin, flip all bits, shift, and be done
1994 $x->binc(); # -3 => -2
1995 my $bin = $x->as_bin();
1996 $bin =~ s/^-0b//; # strip '-0b' prefix
1997 $bin =~ tr/10/01/; # flip bits
1999 if ($y >= CORE::length($bin))
2001 $bin = '0'; # shifting to far right creates -1
2002 # 0, because later increment makes
2003 # that 1, attached '-' makes it '-1'
2004 # because -1 >> x == -1 !
2008 $bin =~ s/.{$y}$//; # cut off at the right side
2009 $bin = '1' . $bin; # extend left side by one dummy '1'
2010 $bin =~ tr/10/01/; # flip bits back
2012 my $res = $self->new('0b'.$bin); # add prefix and convert back
2013 $res->binc(); # remember to increment
2014 $x->{value} = $res->{value}; # take over value
2015 return $x->round(@r); # we are done now, magic, isn't?
2017 # x < 0, n == 2, y == 1
2018 $x->bdec(); # n == 2, but $y == 1: this fixes it
2021 $x->{value} = $CALC->_rsft($x->{value},$y->{value},$n);
2027 #(BINT or num_str, BINT or num_str) return BINT
2031 my ($self,$x,$y,@r) = (ref($_[0]),@_);
2032 # objectify is costly, so avoid it
2033 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
2035 ($self,$x,$y,@r) = objectify(2,@_);
2038 return $x if $x->modify('band');
2040 $r[3] = $y; # no push!
2042 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
2044 my $sx = $x->{sign} eq '+' ? 1 : -1;
2045 my $sy = $y->{sign} eq '+' ? 1 : -1;
2047 if ($sx == 1 && $sy == 1)
2049 $x->{value} = $CALC->_and($x->{value},$y->{value});
2050 return $x->round(@r);
2053 if ($CAN{signed_and})
2055 $x->{value} = $CALC->_signed_and($x->{value},$y->{value},$sx,$sy);
2056 return $x->round(@r);
2060 __emu_band($self,$x,$y,$sx,$sy,@r);
2065 #(BINT or num_str, BINT or num_str) return BINT
2069 my ($self,$x,$y,@r) = (ref($_[0]),@_);
2070 # objectify is costly, so avoid it
2071 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
2073 ($self,$x,$y,@r) = objectify(2,@_);
2076 return $x if $x->modify('bior');
2077 $r[3] = $y; # no push!
2079 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
2081 my $sx = $x->{sign} eq '+' ? 1 : -1;
2082 my $sy = $y->{sign} eq '+' ? 1 : -1;
2084 # the sign of X follows the sign of X, e.g. sign of Y irrelevant for bior()
2086 # don't use lib for negative values
2087 if ($sx == 1 && $sy == 1)
2089 $x->{value} = $CALC->_or($x->{value},$y->{value});
2090 return $x->round(@r);
2093 # if lib can do negative values, let it handle this
2094 if ($CAN{signed_or})
2096 $x->{value} = $CALC->_signed_or($x->{value},$y->{value},$sx,$sy);
2097 return $x->round(@r);
2101 __emu_bior($self,$x,$y,$sx,$sy,@r);
2106 #(BINT or num_str, BINT or num_str) return BINT
2110 my ($self,$x,$y,@r) = (ref($_[0]),@_);
2111 # objectify is costly, so avoid it
2112 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
2114 ($self,$x,$y,@r) = objectify(2,@_);
2117 return $x if $x->modify('bxor');
2118 $r[3] = $y; # no push!
2120 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
2122 my $sx = $x->{sign} eq '+' ? 1 : -1;
2123 my $sy = $y->{sign} eq '+' ? 1 : -1;
2125 # don't use lib for negative values
2126 if ($sx == 1 && $sy == 1)
2128 $x->{value} = $CALC->_xor($x->{value},$y->{value});
2129 return $x->round(@r);
2132 # if lib can do negative values, let it handle this
2133 if ($CAN{signed_xor})
2135 $x->{value} = $CALC->_signed_xor($x->{value},$y->{value},$sx,$sy);
2136 return $x->round(@r);
2140 __emu_bxor($self,$x,$y,$sx,$sy,@r);
2145 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
2147 my $e = $CALC->_len($x->{value});
2148 wantarray ? ($e,0) : $e;
2153 # return the nth decimal digit, negative values count backward, 0 is right
2154 my ($self,$x,$n) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2156 $n = $n->numify() if ref($n);
2157 $CALC->_digit($x->{value},$n||0);
2162 # return the amount of trailing zeros in $x (as scalar)
2164 $x = $class->new($x) unless ref $x;
2166 return 0 if $x->{sign} !~ /^[+-]$/; # NaN, inf, -inf etc
2168 $CALC->_zeros($x->{value}); # must handle odd values, 0 etc
2173 # calculate square root of $x
2174 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2176 return $x if $x->modify('bsqrt');
2178 return $x->bnan() if $x->{sign} !~ /^\+/; # -x or -inf or NaN => NaN
2179 return $x if $x->{sign} eq '+inf'; # sqrt(+inf) == inf
2181 return $upgrade->bsqrt($x,@r) if defined $upgrade;
2183 $x->{value} = $CALC->_sqrt($x->{value});
2189 # calculate $y'th root of $x
2192 my ($self,$x,$y,@r) = (ref($_[0]),@_);
2194 $y = $self->new(2) unless defined $y;
2196 # objectify is costly, so avoid it
2197 if ((!ref($x)) || (ref($x) ne ref($y)))
2199 ($self,$x,$y,@r) = objectify(2,$self || $class,@_);
2202 return $x if $x->modify('broot');
2204 # NaN handling: $x ** 1/0, x or y NaN, or y inf/-inf or y == 0
2205 return $x->bnan() if $x->{sign} !~ /^\+/ || $y->is_zero() ||
2206 $y->{sign} !~ /^\+$/;
2208 return $x->round(@r)
2209 if $x->is_zero() || $x->is_one() || $x->is_inf() || $y->is_one();
2211 return $upgrade->new($x)->broot($upgrade->new($y),@r) if defined $upgrade;
2213 $x->{value} = $CALC->_root($x->{value},$y->{value});
2219 # return a copy of the exponent (here always 0, NaN or 1 for $m == 0)
2220 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2222 if ($x->{sign} !~ /^[+-]$/)
2224 my $s = $x->{sign}; $s =~ s/^[+-]//; # NaN, -inf,+inf => NaN or inf
2225 return $self->new($s);
2227 return $self->bone() if $x->is_zero();
2229 # 12300 => 2 trailing zeros => exponent is 2
2230 $self->new( $CALC->_zeros($x->{value}) );
2235 # return the mantissa (compatible to Math::BigFloat, e.g. reduced)
2236 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2238 if ($x->{sign} !~ /^[+-]$/)
2240 # for NaN, +inf, -inf: keep the sign
2241 return $self->new($x->{sign});
2243 my $m = $x->copy(); delete $m->{_p}; delete $m->{_a};
2245 # that's a bit inefficient:
2246 my $zeros = $CALC->_zeros($m->{value});
2247 $m->brsft($zeros,10) if $zeros != 0;
2253 # return a copy of both the exponent and the mantissa
2254 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
2256 ($x->mantissa(),$x->exponent());
2259 ##############################################################################
2260 # rounding functions
2264 # precision: round to the $Nth digit left (+$n) or right (-$n) from the '.'
2265 # $n == 0 || $n == 1 => round to integer
2266 my $x = shift; my $self = ref($x) || $x; $x = $self->new($x) unless ref $x;
2268 my ($scale,$mode) = $x->_scale_p(@_);
2270 return $x if !defined $scale || $x->modify('bfround'); # no-op
2272 # no-op for BigInts if $n <= 0
2273 $x->bround( $x->length()-$scale, $mode) if $scale > 0;
2275 delete $x->{_a}; # delete to save memory
2276 $x->{_p} = $scale; # store new _p
2280 sub _scan_for_nonzero
2282 # internal, used by bround() to scan for non-zeros after a '5'
2283 my ($x,$pad,$xs,$len) = @_;
2285 return 0 if $len == 1; # "5" is trailed by invisible zeros
2286 my $follow = $pad - 1;
2287 return 0 if $follow > $len || $follow < 1;
2289 # use the string form to check whether only '0's follow or not
2290 substr ($xs,-$follow) =~ /[^0]/ ? 1 : 0;
2295 # Exists to make life easier for switch between MBF and MBI (should we
2296 # autoload fxxx() like MBF does for bxxx()?)
2297 my $x = shift; $x = $class->new($x) unless ref $x;
2303 # accuracy: +$n preserve $n digits from left,
2304 # -$n preserve $n digits from right (f.i. for 0.1234 style in MBF)
2306 # and overwrite the rest with 0's, return normalized number
2307 # do not return $x->bnorm(), but $x
2309 my $x = shift; $x = $class->new($x) unless ref $x;
2310 my ($scale,$mode) = $x->_scale_a(@_);
2311 return $x if !defined $scale || $x->modify('bround'); # no-op
2313 if ($x->is_zero() || $scale == 0)
2315 $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale; # 3 > 2
2318 return $x if $x->{sign} !~ /^[+-]$/; # inf, NaN
2320 # we have fewer digits than we want to scale to
2321 my $len = $x->length();
2322 # convert $scale to a scalar in case it is an object (put's a limit on the
2323 # number length, but this would already limited by memory constraints), makes
2325 $scale = $scale->numify() if ref ($scale);
2327 # scale < 0, but > -len (not >=!)
2328 if (($scale < 0 && $scale < -$len-1) || ($scale >= $len))
2330 $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale; # 3 > 2
2334 # count of 0's to pad, from left (+) or right (-): 9 - +6 => 3, or |-6| => 6
2335 my ($pad,$digit_round,$digit_after);
2336 $pad = $len - $scale;
2337 $pad = abs($scale-1) if $scale < 0;
2339 # do not use digit(), it is very costly for binary => decimal
2340 # getting the entire string is also costly, but we need to do it only once
2341 my $xs = $CALC->_str($x->{value});
2344 # pad: 123: 0 => -1, at 1 => -2, at 2 => -3, at 3 => -4
2345 # pad+1: 123: 0 => 0, at 1 => -1, at 2 => -2, at 3 => -3
2346 $digit_round = '0'; $digit_round = substr($xs,$pl,1) if $pad <= $len;
2347 $pl++; $pl ++ if $pad >= $len;
2348 $digit_after = '0'; $digit_after = substr($xs,$pl,1) if $pad > 0;
2350 # in case of 01234 we round down, for 6789 up, and only in case 5 we look
2351 # closer at the remaining digits of the original $x, remember decision
2352 my $round_up = 1; # default round up
2354 ($mode eq 'trunc') || # trunc by round down
2355 ($digit_after =~ /[01234]/) || # round down anyway,
2357 ($digit_after eq '5') && # not 5000...0000
2358 ($x->_scan_for_nonzero($pad,$xs,$len) == 0) &&
2360 ($mode eq 'even') && ($digit_round =~ /[24680]/) ||
2361 ($mode eq 'odd') && ($digit_round =~ /[13579]/) ||
2362 ($mode eq '+inf') && ($x->{sign} eq '-') ||
2363 ($mode eq '-inf') && ($x->{sign} eq '+') ||
2364 ($mode eq 'zero') # round down if zero, sign adjusted below
2366 my $put_back = 0; # not yet modified
2368 if (($pad > 0) && ($pad <= $len))
2370 substr($xs,-$pad,$pad) = '0' x $pad; # replace with '00...'
2371 $put_back = 1; # need to put back
2375 $x->bzero(); # round to '0'
2378 if ($round_up) # what gave test above?
2380 $put_back = 1; # need to put back
2381 $pad = $len, $xs = '0' x $pad if $scale < 0; # tlr: whack 0.51=>1.0
2383 # we modify directly the string variant instead of creating a number and
2384 # adding it, since that is faster (we already have the string)
2385 my $c = 0; $pad ++; # for $pad == $len case
2386 while ($pad <= $len)
2388 $c = substr($xs,-$pad,1) + 1; $c = '0' if $c eq '10';
2389 substr($xs,-$pad,1) = $c; $pad++;
2390 last if $c != 0; # no overflow => early out
2392 $xs = '1'.$xs if $c == 0;
2395 $x->{value} = $CALC->_new($xs) if $put_back == 1; # put back, if needed
2397 $x->{_a} = $scale if $scale >= 0;
2400 $x->{_a} = $len+$scale;
2401 $x->{_a} = 0 if $scale < -$len;
2408 # return integer less or equal then number; no-op since it's already integer
2409 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2416 # return integer greater or equal then number; no-op since it's already int
2417 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2424 # An object might be asked to return itself as bigint on certain overloaded
2425 # operations. This does exactly this, so that sub classes can simple inherit
2426 # it or override with their own integer conversion routine.
2432 # return as hex string, with prefixed 0x
2433 my $x = shift; $x = $class->new($x) if !ref($x);
2435 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2438 $s = $x->{sign} if $x->{sign} eq '-';
2439 $s . $CALC->_as_hex($x->{value});
2444 # return as binary string, with prefixed 0b
2445 my $x = shift; $x = $class->new($x) if !ref($x);
2447 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2449 my $s = ''; $s = $x->{sign} if $x->{sign} eq '-';
2450 return $s . $CALC->_as_bin($x->{value});
2455 # return as octal string, with prefixed 0
2456 my $x = shift; $x = $class->new($x) if !ref($x);
2458 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2460 my $s = ''; $s = $x->{sign} if $x->{sign} eq '-';
2461 return $s . $CALC->_as_oct($x->{value});
2464 ##############################################################################
2465 # private stuff (internal use only)
2469 # check for strings, if yes, return objects instead
2471 # the first argument is number of args objectify() should look at it will
2472 # return $count+1 elements, the first will be a classname. This is because
2473 # overloaded '""' calls bstr($object,undef,undef) and this would result in
2474 # useless objects being created and thrown away. So we cannot simple loop
2475 # over @_. If the given count is 0, all arguments will be used.
2477 # If the second arg is a ref, use it as class.
2478 # If not, try to use it as classname, unless undef, then use $class
2479 # (aka Math::BigInt). The latter shouldn't happen,though.
2482 # $x->badd(1); => ref x, scalar y
2483 # Class->badd(1,2); => classname x (scalar), scalar x, scalar y
2484 # Class->badd( Class->(1),2); => classname x (scalar), ref x, scalar y
2485 # Math::BigInt::badd(1,2); => scalar x, scalar y
2486 # In the last case we check number of arguments to turn it silently into
2487 # $class,1,2. (We can not take '1' as class ;o)
2488 # badd($class,1) is not supported (it should, eventually, try to add undef)
2489 # currently it tries 'Math::BigInt' + 1, which will not work.
2491 # some shortcut for the common cases
2493 return (ref($_[1]),$_[1]) if (@_ == 2) && ($_[0]||0 == 1) && ref($_[1]);
2495 my $count = abs(shift || 0);
2497 my (@a,$k,$d); # resulting array, temp, and downgrade
2500 # okay, got object as first
2505 # nope, got 1,2 (Class->xxx(1) => Class,1 and not supported)
2507 $a[0] = shift if $_[0] =~ /^[A-Z].*::/; # classname as first?
2511 # disable downgrading, because Math::BigFLoat->foo('1.0','2.0') needs floats
2512 if (defined ${"$a[0]::downgrade"})
2514 $d = ${"$a[0]::downgrade"};
2515 ${"$a[0]::downgrade"} = undef;
2518 my $up = ${"$a[0]::upgrade"};
2519 # print STDERR "# Now in objectify, my class is today $a[0], count = $count\n";
2527 $k = $a[0]->new($k);
2529 elsif (!defined $up && ref($k) ne $a[0])
2531 # foreign object, try to convert to integer
2532 $k->can('as_number') ? $k = $k->as_number() : $k = $a[0]->new($k);
2545 $k = $a[0]->new($k);
2547 elsif (!defined $up && ref($k) ne $a[0])
2549 # foreign object, try to convert to integer
2550 $k->can('as_number') ? $k = $k->as_number() : $k = $a[0]->new($k);
2554 push @a,@_; # return other params, too
2558 require Carp; Carp::croak ("$class objectify needs list context");
2560 ${"$a[0]::downgrade"} = $d;
2564 sub _register_callback
2566 my ($class,$callback) = @_;
2568 if (ref($callback) ne 'CODE')
2571 Carp::croak ("$callback is not a coderef");
2573 $CALLBACKS{$class} = $callback;
2580 $IMPORT++; # remember we did import()
2581 my @a; my $l = scalar @_;
2582 my $warn_or_die = 0; # 0 - no warn, 1 - warn, 2 - die
2583 for ( my $i = 0; $i < $l ; $i++ )
2585 if ($_[$i] eq ':constant')
2587 # this causes overlord er load to step in
2589 integer => sub { $self->new(shift) },
2590 binary => sub { $self->new(shift) };
2592 elsif ($_[$i] eq 'upgrade')
2594 # this causes upgrading
2595 $upgrade = $_[$i+1]; # or undef to disable
2598 elsif ($_[$i] =~ /^(lib|try|only)\z/)
2600 # this causes a different low lib to take care...
2601 $CALC = $_[$i+1] || '';
2602 # lib => 1 (warn on fallback), try => 0 (no warn), only => 2 (die on fallback)
2603 $warn_or_die = 1 if $_[$i] eq 'lib';
2604 $warn_or_die = 2 if $_[$i] eq 'only';
2612 # any non :constant stuff is handled by our parent, Exporter
2617 $self->SUPER::import(@a); # need it for subclasses
2618 $self->export_to_level(1,$self,@a); # need it for MBF
2621 # try to load core math lib
2622 my @c = split /\s*,\s*/,$CALC;
2625 $_ =~ tr/a-zA-Z0-9://cd; # limit to sane characters
2627 push @c, \'FastCalc', \'Calc' # if all fail, try these
2628 if $warn_or_die < 2; # but not for "only"
2629 $CALC = ''; # signal error
2632 # fallback libraries are "marked" as \'string', extract string if nec.
2633 my $lib = $l; $lib = $$l if ref($l);
2635 next if ($lib || '') eq '';
2636 $lib = 'Math::BigInt::'.$lib if $lib !~ /^Math::BigInt/i;
2640 # Perl < 5.6.0 dies with "out of memory!" when eval("") and ':constant' is
2641 # used in the same script, or eval("") inside import().
2642 my @parts = split /::/, $lib; # Math::BigInt => Math BigInt
2643 my $file = pop @parts; $file .= '.pm'; # BigInt => BigInt.pm
2645 $file = File::Spec->catfile (@parts, $file);
2646 eval { require "$file"; $lib->import( @c ); }
2650 eval "use $lib qw/@c/;";
2655 # loaded it ok, see if the api_version() is high enough
2656 if ($lib->can('api_version') && $lib->api_version() >= 1.0)
2659 # api_version matches, check if it really provides anything we need
2663 add mul div sub dec inc
2664 acmp len digit is_one is_zero is_even is_odd
2666 zeros new copy check
2667 from_hex from_oct from_bin as_hex as_bin as_oct
2668 rsft lsft xor and or
2669 mod sqrt root fac pow modinv modpow log_int gcd
2672 if (!$lib->can("_$method"))
2674 if (($WARN{$lib}||0) < 2)
2677 Carp::carp ("$lib is missing method '_$method'");
2678 $WARN{$lib} = 1; # still warn about the lib
2687 if ($warn_or_die > 0 && ref($l))
2690 my $msg = "Math::BigInt: couldn't load specified math lib(s), fallback to $lib";
2691 Carp::carp ($msg) if $warn_or_die == 1;
2692 Carp::croak ($msg) if $warn_or_die == 2;
2694 last; # found a usable one, break
2698 if (($WARN{$lib}||0) < 2)
2700 my $ver = eval "\$$lib\::VERSION" || 'unknown';
2702 Carp::carp ("Cannot load outdated $lib v$ver, please upgrade");
2703 $WARN{$lib} = 2; # never warn again
2711 if ($warn_or_die == 2)
2713 Carp::croak ("Couldn't load specified math lib(s) and fallback disallowed");
2717 Carp::croak ("Couldn't load any math lib(s), not even fallback to Calc.pm");
2722 foreach my $class (keys %CALLBACKS)
2724 &{$CALLBACKS{$class}}($CALC);
2727 # Fill $CAN with the results of $CALC->can(...) for emulating lower math lib
2731 for my $method (qw/ signed_and signed_or signed_xor /)
2733 $CAN{$method} = $CALC->can("_$method") ? 1 : 0;
2741 # create a bigint from a hexadecimal string
2742 my ($self, $hs) = @_;
2744 my $rc = __from_hex($hs);
2746 return $self->bnan() unless defined $rc;
2753 # create a bigint from a hexadecimal string
2754 my ($self, $bs) = @_;
2756 my $rc = __from_bin($bs);
2758 return $self->bnan() unless defined $rc;
2765 # create a bigint from a hexadecimal string
2766 my ($self, $os) = @_;
2768 my $x = $self->bzero();
2771 $os =~ s/([0-7])_([0-7])/$1$2/g;
2772 $os =~ s/([0-7])_([0-7])/$1$2/g;
2774 return $x->bnan() if $os !~ /^[\-\+]?0[0-7]+\z/;
2776 my $sign = '+'; $sign = '-' if $os =~ /^-/;
2778 $os =~ s/^[+-]//; # strip sign
2779 $x->{value} = $CALC->_from_oct($os);
2780 $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
2787 # convert a (ref to) big hex string to BigInt, return undef for error
2790 my $x = Math::BigInt->bzero();
2793 $hs =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
2794 $hs =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
2796 return $x->bnan() if $hs !~ /^[\-\+]?0x[0-9A-Fa-f]+$/;
2798 my $sign = '+'; $sign = '-' if $hs =~ /^-/;
2800 $hs =~ s/^[+-]//; # strip sign
2801 $x->{value} = $CALC->_from_hex($hs);
2802 $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
2809 # convert a (ref to) big binary string to BigInt, return undef for error
2812 my $x = Math::BigInt->bzero();
2815 $bs =~ s/([01])_([01])/$1$2/g;
2816 $bs =~ s/([01])_([01])/$1$2/g;
2817 return $x->bnan() if $bs !~ /^[+-]?0b[01]+$/;
2819 my $sign = '+'; $sign = '-' if $bs =~ /^\-/;
2820 $bs =~ s/^[+-]//; # strip sign
2822 $x->{value} = $CALC->_from_bin($bs);
2823 $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
2829 # input: num_str; output: undef for invalid or
2830 # (\$mantissa_sign,\$mantissa_value,\$mantissa_fraction,\$exp_sign,\$exp_value)
2831 # Internal, take apart a string and return the pieces.
2832 # Strip leading/trailing whitespace, leading zeros, underscore and reject
2836 # strip white space at front, also extranous leading zeros
2837 $x =~ s/^\s*([-]?)0*([0-9])/$1$2/g; # will not strip ' .2'
2838 $x =~ s/^\s+//; # but this will
2839 $x =~ s/\s+$//g; # strip white space at end
2841 # shortcut, if nothing to split, return early
2842 if ($x =~ /^[+-]?[0-9]+\z/)
2844 $x =~ s/^([+-])0*([0-9])/$2/; my $sign = $1 || '+';
2845 return (\$sign, \$x, \'', \'', \0);
2848 # invalid starting char?
2849 return if $x !~ /^[+-]?(\.?[0-9]|0b[0-1]|0x[0-9a-fA-F])/;
2851 return __from_hex($x) if $x =~ /^[\-\+]?0x/; # hex string
2852 return __from_bin($x) if $x =~ /^[\-\+]?0b/; # binary string
2854 # strip underscores between digits
2855 $x =~ s/([0-9])_([0-9])/$1$2/g;
2856 $x =~ s/([0-9])_([0-9])/$1$2/g; # do twice for 1_2_3
2858 # some possible inputs:
2859 # 2.1234 # 0.12 # 1 # 1E1 # 2.134E1 # 434E-10 # 1.02009E-2
2860 # .2 # 1_2_3.4_5_6 # 1.4E1_2_3 # 1e3 # +.2 # 0e999
2862 my ($m,$e,$last) = split /[Ee]/,$x;
2863 return if defined $last; # last defined => 1e2E3 or others
2864 $e = '0' if !defined $e || $e eq "";
2866 # sign,value for exponent,mantint,mantfrac
2867 my ($es,$ev,$mis,$miv,$mfv);
2869 if ($e =~ /^([+-]?)0*([0-9]+)$/) # strip leading zeros
2873 return if $m eq '.' || $m eq '';
2874 my ($mi,$mf,$lastf) = split /\./,$m;
2875 return if defined $lastf; # lastf defined => 1.2.3 or others
2876 $mi = '0' if !defined $mi;
2877 $mi .= '0' if $mi =~ /^[\-\+]?$/;
2878 $mf = '0' if !defined $mf || $mf eq '';
2879 if ($mi =~ /^([+-]?)0*([0-9]+)$/) # strip leading zeros
2881 $mis = $1||'+'; $miv = $2;
2882 return unless ($mf =~ /^([0-9]*?)0*$/); # strip trailing zeros
2884 # handle the 0e999 case here
2885 $ev = 0 if $miv eq '0' && $mfv eq '';
2886 return (\$mis,\$miv,\$mfv,\$es,\$ev);
2889 return; # NaN, not a number
2892 ##############################################################################
2893 # internal calculation routines (others are in Math::BigInt::Calc etc)
2897 # (BINT or num_str, BINT or num_str) return BINT
2898 # does modify first argument
2902 return $x->bnan() if ($x->{sign} eq $nan) || ($ty->{sign} eq $nan);
2903 my $method = ref($x) . '::bgcd';
2905 $x * $ty / &$method($x,$ty);
2908 ###############################################################################
2909 # trigonometric functions
2913 # Calculate PI to N digits. Unless upgrading is in effect, returns the
2914 # result truncated to an integer, that is, always returns '3'.
2918 # called like Math::BigInt::bpi(10);
2919 $n = $self; $self = $class;
2921 $self = ref($self) if ref($self);
2923 return $upgrade->new($n) if defined $upgrade;
2931 # Calculate cosinus(x) to N digits. Unless upgrading is in effect, returns the
2932 # result truncated to an integer.
2933 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2935 return $x if $x->modify('bcos');
2937 return $x->bnan() if $x->{sign} !~ /^[+-]\z/; # -inf +inf or NaN => NaN
2939 return $upgrade->new($x)->bcos(@r) if defined $upgrade;
2941 require Math::BigFloat;
2942 # calculate the result and truncate it to integer
2943 my $t = Math::BigFloat->new($x)->bcos(@r)->as_int();
2945 $x->bone() if $t->is_one();
2946 $x->bzero() if $t->is_zero();
2952 # Calculate sinus(x) to N digits. Unless upgrading is in effect, returns the
2953 # result truncated to an integer.
2954 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2956 return $x if $x->modify('bsin');
2958 return $x->bnan() if $x->{sign} !~ /^[+-]\z/; # -inf +inf or NaN => NaN
2960 return $upgrade->new($x)->bsin(@r) if defined $upgrade;
2962 require Math::BigFloat;
2963 # calculate the result and truncate it to integer
2964 my $t = Math::BigFloat->new($x)->bsin(@r)->as_int();
2966 $x->bone() if $t->is_one();
2967 $x->bzero() if $t->is_zero();
2973 # calculate arcus tangens of ($y/$x)
2976 my ($self,$y,$x,@r) = (ref($_[0]),@_);
2977 # objectify is costly, so avoid it
2978 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
2980 ($self,$y,$x,@r) = objectify(2,@_);
2983 return $y if $y->modify('batan2');
2985 return $y->bnan() if ($y->{sign} eq $nan) || ($x->{sign} eq $nan);
2987 return $y->bzero() if $y->is_zero() && $x->{sign} eq '+'; # x >= 0
2990 # +-inf => --PI/2 => +-1
2991 return $y->bone( substr($y->{sign},0,1) ) if $y->{sign} =~ /^[+-]inf$/;
2993 return $upgrade->new($y)->batan2($upgrade->new($x),@r) if defined $upgrade;
2995 require Math::BigFloat;
2996 my $r = Math::BigFloat->new($y)->batan2(Math::BigFloat->new($x),@r)->as_int();
2998 $x->{value} = $r->{value};
2999 $x->{sign} = $r->{sign};
3006 # Calculate arcus tangens of x to N digits. Unless upgrading is in effect, returns the
3007 # result truncated to an integer.
3008 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
3010 return $x if $x->modify('batan');
3012 return $x->bnan() if $x->{sign} !~ /^[+-]\z/; # -inf +inf or NaN => NaN
3014 return $upgrade->new($x)->batan(@r) if defined $upgrade;
3016 # calculate the result and truncate it to integer
3017 my $t = Math::BigFloat->new($x)->batan(@r);
3019 $x->{value} = $CALC->_new( $x->as_int()->bstr() );
3023 ###############################################################################
3024 # this method returns 0 if the object can be modified, or 1 if not.
3025 # We use a fast constant sub() here, to avoid costly calls. Subclasses
3026 # may override it with special code (f.i. Math::BigInt::Constant does so)
3028 sub modify () { 0; }
3037 Math::BigInt - Arbitrary size integer/float math package
3043 # or make it faster: install (optional) Math::BigInt::GMP
3044 # and always use (it will fall back to pure Perl if the
3045 # GMP library is not installed):
3047 # will warn if Math::BigInt::GMP cannot be found
3048 use Math::BigInt lib => 'GMP';
3050 # to supress the warning use this:
3051 # use Math::BigInt try => 'GMP';
3053 my $str = '1234567890';
3054 my @values = (64,74,18);
3055 my $n = 1; my $sign = '-';
3058 my $x = Math::BigInt->new($str); # defaults to 0
3059 my $y = $x->copy(); # make a true copy
3060 my $nan = Math::BigInt->bnan(); # create a NotANumber
3061 my $zero = Math::BigInt->bzero(); # create a +0
3062 my $inf = Math::BigInt->binf(); # create a +inf
3063 my $inf = Math::BigInt->binf('-'); # create a -inf
3064 my $one = Math::BigInt->bone(); # create a +1
3065 my $mone = Math::BigInt->bone('-'); # create a -1
3067 my $pi = Math::BigInt->bpi(); # returns '3'
3068 # see Math::BigFloat::bpi()
3070 $h = Math::BigInt->new('0x123'); # from hexadecimal
3071 $b = Math::BigInt->new('0b101'); # from binary
3072 $o = Math::BigInt->from_oct('0101'); # from octal
3074 # Testing (don't modify their arguments)
3075 # (return true if the condition is met, otherwise false)
3077 $x->is_zero(); # if $x is +0
3078 $x->is_nan(); # if $x is NaN
3079 $x->is_one(); # if $x is +1
3080 $x->is_one('-'); # if $x is -1
3081 $x->is_odd(); # if $x is odd
3082 $x->is_even(); # if $x is even
3083 $x->is_pos(); # if $x >= 0
3084 $x->is_neg(); # if $x < 0
3085 $x->is_inf($sign); # if $x is +inf, or -inf (sign is default '+')
3086 $x->is_int(); # if $x is an integer (not a float)
3088 # comparing and digit/sign extraction
3089 $x->bcmp($y); # compare numbers (undef,<0,=0,>0)
3090 $x->bacmp($y); # compare absolutely (undef,<0,=0,>0)
3091 $x->sign(); # return the sign, either +,- or NaN
3092 $x->digit($n); # return the nth digit, counting from right
3093 $x->digit(-$n); # return the nth digit, counting from left
3095 # The following all modify their first argument. If you want to preserve
3096 # $x, use $z = $x->copy()->bXXX($y); See under L<CAVEATS> for why this is
3097 # necessary when mixing $a = $b assignments with non-overloaded math.
3099 $x->bzero(); # set $x to 0
3100 $x->bnan(); # set $x to NaN
3101 $x->bone(); # set $x to +1
3102 $x->bone('-'); # set $x to -1
3103 $x->binf(); # set $x to inf
3104 $x->binf('-'); # set $x to -inf
3106 $x->bneg(); # negation
3107 $x->babs(); # absolute value
3108 $x->bnorm(); # normalize (no-op in BigInt)
3109 $x->bnot(); # two's complement (bit wise not)
3110 $x->binc(); # increment $x by 1
3111 $x->bdec(); # decrement $x by 1
3113 $x->badd($y); # addition (add $y to $x)
3114 $x->bsub($y); # subtraction (subtract $y from $x)
3115 $x->bmul($y); # multiplication (multiply $x by $y)
3116 $x->bdiv($y); # divide, set $x to quotient
3117 # return (quo,rem) or quo if scalar
3119 $x->bmuladd($y,$z); # $x = $x * $y + $z
3121 $x->bmod($y); # modulus (x % y)
3122 $x->bmodpow($exp,$mod); # modular exponentation (($num**$exp) % $mod))
3123 $x->bmodinv($mod); # the inverse of $x in the given modulus $mod
3125 $x->bpow($y); # power of arguments (x ** y)
3126 $x->blsft($y); # left shift in base 2
3127 $x->brsft($y); # right shift in base 2
3128 # returns (quo,rem) or quo if in scalar context
3129 $x->blsft($y,$n); # left shift by $y places in base $n
3130 $x->brsft($y,$n); # right shift by $y places in base $n
3131 # returns (quo,rem) or quo if in scalar context
3133 $x->band($y); # bitwise and
3134 $x->bior($y); # bitwise inclusive or
3135 $x->bxor($y); # bitwise exclusive or
3136 $x->bnot(); # bitwise not (two's complement)
3138 $x->bsqrt(); # calculate square-root
3139 $x->broot($y); # $y'th root of $x (e.g. $y == 3 => cubic root)
3140 $x->bfac(); # factorial of $x (1*2*3*4*..$x)
3142 $x->bnok($y); # x over y (binomial coefficient n over k)
3144 $x->blog(); # logarithm of $x to base e (Euler's number)
3145 $x->blog($base); # logarithm of $x to base $base (f.i. 2)
3146 $x->bexp(); # calculate e ** $x where e is Euler's number
3148 $x->round($A,$P,$mode); # round to accuracy or precision using mode $mode
3149 $x->bround($n); # accuracy: preserve $n digits
3150 $x->bfround($n); # round to $nth digit, no-op for BigInts
3152 # The following do not modify their arguments in BigInt (are no-ops),
3153 # but do so in BigFloat:
3155 $x->bfloor(); # return integer less or equal than $x
3156 $x->bceil(); # return integer greater or equal than $x
3158 # The following do not modify their arguments:
3160 # greatest common divisor (no OO style)
3161 my $gcd = Math::BigInt::bgcd(@values);
3162 # lowest common multiplicator (no OO style)
3163 my $lcm = Math::BigInt::blcm(@values);
3165 $x->length(); # return number of digits in number
3166 ($xl,$f) = $x->length(); # length of number and length of fraction part,
3167 # latter is always 0 digits long for BigInts
3169 $x->exponent(); # return exponent as BigInt
3170 $x->mantissa(); # return (signed) mantissa as BigInt
3171 $x->parts(); # return (mantissa,exponent) as BigInt
3172 $x->copy(); # make a true copy of $x (unlike $y = $x;)
3173 $x->as_int(); # return as BigInt (in BigInt: same as copy())
3174 $x->numify(); # return as scalar (might overflow!)
3176 # conversation to string (do not modify their argument)
3177 $x->bstr(); # normalized string (e.g. '3')
3178 $x->bsstr(); # norm. string in scientific notation (e.g. '3E0')
3179 $x->as_hex(); # as signed hexadecimal string with prefixed 0x
3180 $x->as_bin(); # as signed binary string with prefixed 0b
3181 $x->as_oct(); # as signed octal string with prefixed 0
3184 # precision and accuracy (see section about rounding for more)
3185 $x->precision(); # return P of $x (or global, if P of $x undef)
3186 $x->precision($n); # set P of $x to $n
3187 $x->accuracy(); # return A of $x (or global, if A of $x undef)
3188 $x->accuracy($n); # set A $x to $n
3191 Math::BigInt->precision(); # get/set global P for all BigInt objects
3192 Math::BigInt->accuracy(); # get/set global A for all BigInt objects
3193 Math::BigInt->round_mode(); # get/set global round mode, one of
3194 # 'even', 'odd', '+inf', '-inf', 'zero', 'trunc' or 'common'
3195 Math::BigInt->config(); # return hash containing configuration
3199 All operators (including basic math operations) are overloaded if you
3200 declare your big integers as
3202 $i = new Math::BigInt '123_456_789_123_456_789';
3204 Operations with overloaded operators preserve the arguments which is
3205 exactly what you expect.
3211 Input values to these routines may be any string, that looks like a number
3212 and results in an integer, including hexadecimal and binary numbers.
3214 Scalars holding numbers may also be passed, but note that non-integer numbers
3215 may already have lost precision due to the conversation to float. Quote
3216 your input if you want BigInt to see all the digits:
3218 $x = Math::BigInt->new(12345678890123456789); # bad
3219 $x = Math::BigInt->new('12345678901234567890'); # good
3221 You can include one underscore between any two digits.
3223 This means integer values like 1.01E2 or even 1000E-2 are also accepted.
3224 Non-integer values result in NaN.
3226 Hexadecimal (prefixed with "0x") and binary numbers (prefixed with "0b")
3227 are accepted, too. Please note that octal numbers are not recognized
3228 by new(), so the following will print "123":
3230 perl -MMath::BigInt -le 'print Math::BigInt->new("0123")'
3232 To convert an octal number, use from_oct();
3234 perl -MMath::BigInt -le 'print Math::BigInt->from_oct("0123")'
3236 Currently, Math::BigInt::new() defaults to 0, while Math::BigInt::new('')
3237 results in 'NaN'. This might change in the future, so use always the following
3238 explicit forms to get a zero or NaN:
3240 $zero = Math::BigInt->bzero();
3241 $nan = Math::BigInt->bnan();
3243 C<bnorm()> on a BigInt object is now effectively a no-op, since the numbers
3244 are always stored in normalized form. If passed a string, creates a BigInt
3245 object from the input.
3249 Output values are BigInt objects (normalized), except for the methods which
3250 return a string (see L<SYNOPSIS>).
3252 Some routines (C<is_odd()>, C<is_even()>, C<is_zero()>, C<is_one()>,
3253 C<is_nan()>, etc.) return true or false, while others (C<bcmp()>, C<bacmp()>)
3254 return either undef (if NaN is involved), <0, 0 or >0 and are suited for sort.
3260 Each of the methods below (except config(), accuracy() and precision())
3261 accepts three additional parameters. These arguments C<$A>, C<$P> and C<$R>
3262 are C<accuracy>, C<precision> and C<round_mode>. Please see the section about
3263 L<ACCURACY and PRECISION> for more information.
3269 print Dumper ( Math::BigInt->config() );
3270 print Math::BigInt->config()->{lib},"\n";
3272 Returns a hash containing the configuration, e.g. the version number, lib
3273 loaded etc. The following hash keys are currently filled in with the
3274 appropriate information.
3278 ============================================================
3279 lib Name of the low-level math library
3281 lib_version Version of low-level math library (see 'lib')
3283 class The class name of config() you just called
3285 upgrade To which class math operations might be upgraded
3287 downgrade To which class math operations might be downgraded
3289 precision Global precision
3291 accuracy Global accuracy
3293 round_mode Global round mode
3295 version version number of the class you used
3297 div_scale Fallback accuracy for div
3299 trap_nan If true, traps creation of NaN via croak()
3301 trap_inf If true, traps creation of +inf/-inf via croak()
3304 The following values can be set by passing C<config()> a reference to a hash:
3307 upgrade downgrade precision accuracy round_mode div_scale
3311 $new_cfg = Math::BigInt->config( { trap_inf => 1, precision => 5 } );
3315 $x->accuracy(5); # local for $x
3316 CLASS->accuracy(5); # global for all members of CLASS
3317 # Note: This also applies to new()!
3319 $A = $x->accuracy(); # read out accuracy that affects $x
3320 $A = CLASS->accuracy(); # read out global accuracy
3322 Set or get the global or local accuracy, aka how many significant digits the
3323 results have. If you set a global accuracy, then this also applies to new()!
3325 Warning! The accuracy I<sticks>, e.g. once you created a number under the
3326 influence of C<< CLASS->accuracy($A) >>, all results from math operations with
3327 that number will also be rounded.
3329 In most cases, you should probably round the results explicitly using one of
3330 L<round()>, L<bround()> or L<bfround()> or by passing the desired accuracy
3331 to the math operation as additional parameter:
3333 my $x = Math::BigInt->new(30000);
3334 my $y = Math::BigInt->new(7);
3335 print scalar $x->copy()->bdiv($y, 2); # print 4300
3336 print scalar $x->copy()->bdiv($y)->bround(2); # print 4300
3338 Please see the section about L<ACCURACY AND PRECISION> for further details.
3340 Value must be greater than zero. Pass an undef value to disable it:
3342 $x->accuracy(undef);
3343 Math::BigInt->accuracy(undef);
3345 Returns the current accuracy. For C<$x->accuracy()> it will return either the
3346 local accuracy, or if not defined, the global. This means the return value
3347 represents the accuracy that will be in effect for $x:
3349 $y = Math::BigInt->new(1234567); # unrounded
3350 print Math::BigInt->accuracy(4),"\n"; # set 4, print 4
3351 $x = Math::BigInt->new(123456); # $x will be automatically rounded!
3352 print "$x $y\n"; # '123500 1234567'
3353 print $x->accuracy(),"\n"; # will be 4
3354 print $y->accuracy(),"\n"; # also 4, since global is 4
3355 print Math::BigInt->accuracy(5),"\n"; # set to 5, print 5
3356 print $x->accuracy(),"\n"; # still 4
3357 print $y->accuracy(),"\n"; # 5, since global is 5
3359 Note: Works also for subclasses like Math::BigFloat. Each class has it's own
3360 globals separated from Math::BigInt, but it is possible to subclass
3361 Math::BigInt and make the globals of the subclass aliases to the ones from
3366 $x->precision(-2); # local for $x, round at the second digit right of the dot
3367 $x->precision(2); # ditto, round at the second digit left of the dot
3369 CLASS->precision(5); # Global for all members of CLASS
3370 # This also applies to new()!
3371 CLASS->precision(-5); # ditto
3373 $P = CLASS->precision(); # read out global precision
3374 $P = $x->precision(); # read out precision that affects $x
3376 Note: You probably want to use L<accuracy()> instead. With L<accuracy> you
3377 set the number of digits each result should have, with L<precision> you
3378 set the place where to round!
3380 C<precision()> sets or gets the global or local precision, aka at which digit
3381 before or after the dot to round all results. A set global precision also
3382 applies to all newly created numbers!
3384 In Math::BigInt, passing a negative number precision has no effect since no
3385 numbers have digits after the dot. In L<Math::BigFloat>, it will round all
3386 results to P digits after the dot.
3388 Please see the section about L<ACCURACY AND PRECISION> for further details.
3390 Pass an undef value to disable it:
3392 $x->precision(undef);
3393 Math::BigInt->precision(undef);
3395 Returns the current precision. For C<$x->precision()> it will return either the
3396 local precision of $x, or if not defined, the global. This means the return
3397 value represents the prevision that will be in effect for $x:
3399 $y = Math::BigInt->new(1234567); # unrounded
3400 print Math::BigInt->precision(4),"\n"; # set 4, print 4
3401 $x = Math::BigInt->new(123456); # will be automatically rounded
3402 print $x; # print "120000"!
3404 Note: Works also for subclasses like L<Math::BigFloat>. Each class has its
3405 own globals separated from Math::BigInt, but it is possible to subclass
3406 Math::BigInt and make the globals of the subclass aliases to the ones from
3413 Shifts $x right by $y in base $n. Default is base 2, used are usually 10 and
3414 2, but others work, too.
3416 Right shifting usually amounts to dividing $x by $n ** $y and truncating the
3420 $x = Math::BigInt->new(10);
3421 $x->brsft(1); # same as $x >> 1: 5
3422 $x = Math::BigInt->new(1234);
3423 $x->brsft(2,10); # result 12
3425 There is one exception, and that is base 2 with negative $x:
3428 $x = Math::BigInt->new(-5);
3431 This will print -3, not -2 (as it would if you divide -5 by 2 and truncate the
3436 $x = Math::BigInt->new($str,$A,$P,$R);
3438 Creates a new BigInt object from a scalar or another BigInt object. The
3439 input is accepted as decimal, hex (with leading '0x') or binary (with leading
3442 See L<Input> for more info on accepted input formats.
3446 $x = Math::BigInt->from_oct("0775"); # input is octal
3450 $x = Math::BigInt->from_hex("0xcafe"); # input is hexadecimal
3454 $x = Math::BigInt->from_oct("0x10011"); # input is binary
3458 $x = Math::BigInt->bnan();
3460 Creates a new BigInt object representing NaN (Not A Number).
3461 If used on an object, it will set it to NaN:
3467 $x = Math::BigInt->bzero();
3469 Creates a new BigInt object representing zero.
3470 If used on an object, it will set it to zero:
3476 $x = Math::BigInt->binf($sign);
3478 Creates a new BigInt object representing infinity. The optional argument is
3479 either '-' or '+', indicating whether you want infinity or minus infinity.
3480 If used on an object, it will set it to infinity:
3487 $x = Math::BigInt->binf($sign);
3489 Creates a new BigInt object representing one. The optional argument is
3490 either '-' or '+', indicating whether you want one or minus one.
3491 If used on an object, it will set it to one:
3496 =head2 is_one()/is_zero()/is_nan()/is_inf()
3499 $x->is_zero(); # true if arg is +0
3500 $x->is_nan(); # true if arg is NaN
3501 $x->is_one(); # true if arg is +1
3502 $x->is_one('-'); # true if arg is -1
3503 $x->is_inf(); # true if +inf
3504 $x->is_inf('-'); # true if -inf (sign is default '+')
3506 These methods all test the BigInt for being one specific value and return
3507 true or false depending on the input. These are faster than doing something
3512 =head2 is_pos()/is_neg()/is_positive()/is_negative()
3514 $x->is_pos(); # true if > 0
3515 $x->is_neg(); # true if < 0
3517 The methods return true if the argument is positive or negative, respectively.
3518 C<NaN> is neither positive nor negative, while C<+inf> counts as positive, and
3519 C<-inf> is negative. A C<zero> is neither positive nor negative.
3521 These methods are only testing the sign, and not the value.
3523 C<is_positive()> and C<is_negative()> are aliases to C<is_pos()> and
3524 C<is_neg()>, respectively. C<is_positive()> and C<is_negative()> were
3525 introduced in v1.36, while C<is_pos()> and C<is_neg()> were only introduced
3528 =head2 is_odd()/is_even()/is_int()
3530 $x->is_odd(); # true if odd, false for even
3531 $x->is_even(); # true if even, false for odd
3532 $x->is_int(); # true if $x is an integer
3534 The return true when the argument satisfies the condition. C<NaN>, C<+inf>,
3535 C<-inf> are not integers and are neither odd nor even.
3537 In BigInt, all numbers except C<NaN>, C<+inf> and C<-inf> are integers.
3543 Compares $x with $y and takes the sign into account.
3544 Returns -1, 0, 1 or undef.
3550 Compares $x with $y while ignoring their. Returns -1, 0, 1 or undef.
3556 Return the sign, of $x, meaning either C<+>, C<->, C<-inf>, C<+inf> or NaN.
3558 If you want $x to have a certain sign, use one of the following methods:
3561 $x->babs()->bneg(); # '-'
3563 $x->binf(); # '+inf'
3564 $x->binf('-'); # '-inf'
3568 $x->digit($n); # return the nth digit, counting from right
3570 If C<$n> is negative, returns the digit counting from left.
3576 Negate the number, e.g. change the sign between '+' and '-', or between '+inf'
3577 and '-inf', respectively. Does nothing for NaN or zero.
3583 Set the number to its absolute value, e.g. change the sign from '-' to '+'
3584 and from '-inf' to '+inf', respectively. Does nothing for NaN or positive
3589 $x->bnorm(); # normalize (no-op)
3595 Two's complement (bitwise not). This is equivalent to
3603 $x->binc(); # increment x by 1
3607 $x->bdec(); # decrement x by 1
3611 $x->badd($y); # addition (add $y to $x)
3615 $x->bsub($y); # subtraction (subtract $y from $x)
3619 $x->bmul($y); # multiplication (multiply $x by $y)
3625 Multiply $x by $y, and then add $z to the result,
3627 This method was added in v1.87 of Math::BigInt (June 2007).
3631 $x->bdiv($y); # divide, set $x to quotient
3632 # return (quo,rem) or quo if scalar
3636 $x->bmod($y); # modulus (x % y)
3640 num->bmodinv($mod); # modular inverse
3642 Returns the inverse of C<$num> in the given modulus C<$mod>. 'C<NaN>' is
3643 returned unless C<$num> is relatively prime to C<$mod>, i.e. unless
3644 C<bgcd($num, $mod)==1>.
3648 $num->bmodpow($exp,$mod); # modular exponentation
3649 # ($num**$exp % $mod)
3651 Returns the value of C<$num> taken to the power C<$exp> in the modulus
3652 C<$mod> using binary exponentation. C<bmodpow> is far superior to
3657 because it is much faster - it reduces internal variables into
3658 the modulus whenever possible, so it operates on smaller numbers.
3660 C<bmodpow> also supports negative exponents.
3662 bmodpow($num, -1, $mod)
3664 is exactly equivalent to
3670 $x->bpow($y); # power of arguments (x ** y)
3674 $x->blog($base, $accuracy); # logarithm of x to the base $base
3676 If C<$base> is not defined, Euler's number (e) is used:
3678 print $x->blog(undef, 100); # log(x) to 100 digits
3682 $x->bexp($accuracy); # calculate e ** X
3684 Calculates the expression C<e ** $x> where C<e> is Euler's number.
3686 This method was added in v1.82 of Math::BigInt (April 2007).
3692 $x->bnok($y); # x over y (binomial coefficient n over k)
3694 Calculates the binomial coefficient n over k, also called the "choose"
3695 function. The result is equivalent to:
3701 This method was added in v1.84 of Math::BigInt (April 2007).
3705 print Math::BigInt->bpi(100), "\n"; # 3
3707 Returns PI truncated to an integer, with the argument being ignored. This means
3708 under BigInt this always returns C<3>.
3710 If upgrading is in effect, returns PI, rounded to N digits with the
3711 current rounding mode:
3714 use Math::BigInt upgrade => Math::BigFloat;
3715 print Math::BigInt->bpi(3), "\n"; # 3.14
3716 print Math::BigInt->bpi(100), "\n"; # 3.1415....
3718 This method was added in v1.87 of Math::BigInt (June 2007).
3722 my $x = Math::BigInt->new(1);
3723 print $x->bcos(100), "\n";
3725 Calculate the cosinus of $x, modifying $x in place.
3727 In BigInt, unless upgrading is in effect, the result is truncated to an
3730 This method was added in v1.87 of Math::BigInt (June 2007).
3734 my $x = Math::BigInt->new(1);
3735 print $x->bsin(100), "\n";
3737 Calculate the sinus of $x, modifying $x in place.
3739 In BigInt, unless upgrading is in effect, the result is truncated to an
3742 This method was added in v1.87 of Math::BigInt (June 2007).
3746 my $x = Math::BigInt->new(1);
3747 my $y = Math::BigInt->new(1);
3748 print $y->batan2($x), "\n";
3750 Calculate the arcus tangens of C<$y> divided by C<$x>, modifying $y in place.
3752 In BigInt, unless upgrading is in effect, the result is truncated to an
3755 This method was added in v1.87 of Math::BigInt (June 2007).
3759 my $x = Math::BigFloat->new(0.5);
3760 print $x->batan(100), "\n";
3762 Calculate the arcus tangens of $x, modifying $x in place.
3764 In BigInt, unless upgrading is in effect, the result is truncated to an
3767 This method was added in v1.87 of Math::BigInt (June 2007).
3771 $x->blsft($y); # left shift in base 2
3772 $x->blsft($y,$n); # left shift, in base $n (like 10)
3776 $x->brsft($y); # right shift in base 2
3777 $x->brsft($y,$n); # right shift, in base $n (like 10)
3781 $x->band($y); # bitwise and
3785 $x->bior($y); # bitwise inclusive or
3789 $x->bxor($y); # bitwise exclusive or
3793 $x->bnot(); # bitwise not (two's complement)
3797 $x->bsqrt(); # calculate square-root
3803 Calculates the N'th root of C<$x>.
3807 $x->bfac(); # factorial of $x (1*2*3*4*..$x)
3811 $x->round($A,$P,$round_mode);
3813 Round $x to accuracy C<$A> or precision C<$P> using the round mode
3818 $x->bround($N); # accuracy: preserve $N digits
3822 $x->bfround($N); # round to $Nth digit, no-op for BigInts
3828 Set $x to the integer less or equal than $x. This is a no-op in BigInt, but
3829 does change $x in BigFloat.
3835 Set $x to the integer greater or equal than $x. This is a no-op in BigInt, but
3836 does change $x in BigFloat.
3840 bgcd(@values); # greatest common divisor (no OO style)
3844 blcm(@values); # lowest common multiplicator (no OO style)
3849 ($xl,$fl) = $x->length();
3851 Returns the number of digits in the decimal representation of the number.
3852 In list context, returns the length of the integer and fraction part. For
3853 BigInt's, the length of the fraction part will always be 0.
3859 Return the exponent of $x as BigInt.
3865 Return the signed mantissa of $x as BigInt.
3869 $x->parts(); # return (mantissa,exponent) as BigInt
3873 $x->copy(); # make a true copy of $x (unlike $y = $x;)
3875 =head2 as_int()/as_number()
3879 Returns $x as a BigInt (truncated towards zero). In BigInt this is the same as
3882 C<as_number()> is an alias to this method. C<as_number> was introduced in
3883 v1.22, while C<as_int()> was only introduced in v1.68.
3889 Returns a normalized string representation of C<$x>.
3893 $x->bsstr(); # normalized string in scientific notation
3897 $x->as_hex(); # as signed hexadecimal string with prefixed 0x
3901 $x->as_bin(); # as signed binary string with prefixed 0b
3905 $x->as_oct(); # as signed octal string with prefixed 0
3911 This returns a normal Perl scalar from $x. It is used automatically
3912 whenever a scalar is needed, for instance in array index operations.
3914 This loses precision, to avoid this use L<as_int()> instead.
3918 $x->modify('bpowd');
3920 This method returns 0 if the object can be modified with the given
3921 peration, or 1 if not.
3923 This is used for instance by L<Math::BigInt::Constant>.
3925 =head2 upgrade()/downgrade()
3927 Set/get the class for downgrade/upgrade operations. Thuis is used
3928 for instance by L<bignum>. The defaults are '', thus the following
3929 operation will create a BigInt, not a BigFloat:
3931 my $i = Math::BigInt->new(123);
3932 my $f = Math::BigFloat->new('123.1');
3934 print $i + $f,"\n"; # print 246
3938 Set/get the number of digits for the default precision in divide
3943 Set/get the current round mode.
3945 =head1 ACCURACY and PRECISION
3947 Since version v1.33, Math::BigInt and Math::BigFloat have full support for
3948 accuracy and precision based rounding, both automatically after every
3949 operation, as well as manually.
3951 This section describes the accuracy/precision handling in Math::Big* as it
3952 used to be and as it is now, complete with an explanation of all terms and
3955 Not yet implemented things (but with correct description) are marked with '!',
3956 things that need to be answered are marked with '?'.
3958 In the next paragraph follows a short description of terms used here (because
3959 these may differ from terms used by others people or documentation).
3961 During the rest of this document, the shortcuts A (for accuracy), P (for
3962 precision), F (fallback) and R (rounding mode) will be used.
3966 A fixed number of digits before (positive) or after (negative)
3967 the decimal point. For example, 123.45 has a precision of -2. 0 means an
3968 integer like 123 (or 120). A precision of 2 means two digits to the left
3969 of the decimal point are zero, so 123 with P = 1 becomes 120. Note that
3970 numbers with zeros before the decimal point may have different precisions,
3971 because 1200 can have p = 0, 1 or 2 (depending on what the inital value
3972 was). It could also have p < 0, when the digits after the decimal point
3975 The string output (of floating point numbers) will be padded with zeros:
3977 Initial value P A Result String
3978 ------------------------------------------------------------
3979 1234.01 -3 1000 1000
3982 1234.001 1 1234 1234.0
3984 1234.01 2 1234.01 1234.01
3985 1234.01 5 1234.01 1234.01000
3987 For BigInts, no padding occurs.
3991 Number of significant digits. Leading zeros are not counted. A
3992 number may have an accuracy greater than the non-zero digits
3993 when there are zeros in it or trailing zeros. For example, 123.456 has
3994 A of 6, 10203 has 5, 123.0506 has 7, 123.450000 has 8 and 0.000123 has 3.
3996 The string output (of floating point numbers) will be padded with zeros:
3998 Initial value P A Result String
3999 ------------------------------------------------------------
4001 1234.01 6 1234.01 1234.01
4002 1234.1 8 1234.1 1234.1000
4004 For BigInts, no padding occurs.
4008 When both A and P are undefined, this is used as a fallback accuracy when
4011 =head2 Rounding mode R
4013 When rounding a number, different 'styles' or 'kinds'
4014 of rounding are possible. (Note that random rounding, as in
4015 Math::Round, is not implemented.)
4021 truncation invariably removes all digits following the
4022 rounding place, replacing them with zeros. Thus, 987.65 rounded
4023 to tens (P=1) becomes 980, and rounded to the fourth sigdig
4024 becomes 987.6 (A=4). 123.456 rounded to the second place after the
4025 decimal point (P=-2) becomes 123.46.
4027 All other implemented styles of rounding attempt to round to the
4028 "nearest digit." If the digit D immediately to the right of the
4029 rounding place (skipping the decimal point) is greater than 5, the
4030 number is incremented at the rounding place (possibly causing a
4031 cascade of incrementation): e.g. when rounding to units, 0.9 rounds
4032 to 1, and -19.9 rounds to -20. If D < 5, the number is similarly
4033 truncated at the rounding place: e.g. when rounding to units, 0.4
4034 rounds to 0, and -19.4 rounds to -19.
4036 However the results of other styles of rounding differ if the
4037 digit immediately to the right of the rounding place (skipping the
4038 decimal point) is 5 and if there are no digits, or no digits other
4039 than 0, after that 5. In such cases:
4043 rounds the digit at the rounding place to 0, 2, 4, 6, or 8
4044 if it is not already. E.g., when rounding to the first sigdig, 0.45
4045 becomes 0.4, -0.55 becomes -0.6, but 0.4501 becomes 0.5.
4049 rounds the digit at the rounding place to 1, 3, 5, 7, or 9 if
4050 it is not already. E.g., when rounding to the first sigdig, 0.45
4051 becomes 0.5, -0.55 becomes -0.5, but 0.5501 becomes 0.6.
4055 round to plus infinity, i.e. always round up. E.g., when
4056 rounding to the first sigdig, 0.45 becomes 0.5, -0.55 becomes -0.5,
4057 and 0.4501 also becomes 0.5.
4061 round to minus infinity, i.e. always round down. E.g., when
4062 rounding to the first sigdig, 0.45 becomes 0.4, -0.55 becomes -0.6,
4063 but 0.4501 becomes 0.5.
4067 round to zero, i.e. positive numbers down, negative ones up.
4068 E.g., when rounding to the first sigdig, 0.45 becomes 0.4, -0.55
4069 becomes -0.5, but 0.4501 becomes 0.5.
4073 round up if the digit immediately to the right of the rounding place
4074 is 5 or greater, otherwise round down. E.g., 0.15 becomes 0.2 and
4079 The handling of A & P in MBI/MBF (the old core code shipped with Perl
4080 versions <= 5.7.2) is like this:
4086 * ffround($p) is able to round to $p number of digits after the decimal
4088 * otherwise P is unused
4090 =item Accuracy (significant digits)
4092 * fround($a) rounds to $a significant digits
4093 * only fdiv() and fsqrt() take A as (optional) paramater
4094 + other operations simply create the same number (fneg etc), or more (fmul)
4096 + rounding/truncating is only done when explicitly calling one of fround
4097 or ffround, and never for BigInt (not implemented)
4098 * fsqrt() simply hands its accuracy argument over to fdiv.
4099 * the documentation and the comment in the code indicate two different ways
4100 on how fdiv() determines the maximum number of digits it should calculate,
4101 and the actual code does yet another thing
4103 max($Math::BigFloat::div_scale,length(dividend)+length(divisor))
4105 result has at most max(scale, length(dividend), length(divisor)) digits
4107 scale = max(scale, length(dividend)-1,length(divisor)-1);
4108 scale += length(divisor) - length(dividend);
4109 So for lx = 3, ly = 9, scale = 10, scale will actually be 16 (10+9-3).
4110 Actually, the 'difference' added to the scale is calculated from the
4111 number of "significant digits" in dividend and divisor, which is derived
4112 by looking at the length of the mantissa. Which is wrong, since it includes
4113 the + sign (oops) and actually gets 2 for '+100' and 4 for '+101'. Oops
4114 again. Thus 124/3 with div_scale=1 will get you '41.3' based on the strange
4115 assumption that 124 has 3 significant digits, while 120/7 will get you
4116 '17', not '17.1' since 120 is thought to have 2 significant digits.
4117 The rounding after the division then uses the remainder and $y to determine
4118 wether it must round up or down.
4119 ? I have no idea which is the right way. That's why I used a slightly more
4120 ? simple scheme and tweaked the few failing testcases to match it.
4124 This is how it works now:
4128 =item Setting/Accessing
4130 * You can set the A global via C<< Math::BigInt->accuracy() >> or
4131 C<< Math::BigFloat->accuracy() >> or whatever class you are using.
4132 * You can also set P globally by using C<< Math::SomeClass->precision() >>
4134 * Globals are classwide, and not inherited by subclasses.
4135 * to undefine A, use C<< Math::SomeCLass->accuracy(undef); >>
4136 * to undefine P, use C<< Math::SomeClass->precision(undef); >>
4137 * Setting C<< Math::SomeClass->accuracy() >> clears automatically
4138 C<< Math::SomeClass->precision() >>, and vice versa.
4139 * To be valid, A must be > 0, P can have any value.
4140 * If P is negative, this means round to the P'th place to the right of the
4141 decimal point; positive values mean to the left of the decimal point.
4142 P of 0 means round to integer.
4143 * to find out the current global A, use C<< Math::SomeClass->accuracy() >>
4144 * to find out the current global P, use C<< Math::SomeClass->precision() >>
4145 * use C<< $x->accuracy() >> respective C<< $x->precision() >> for the local
4146 setting of C<< $x >>.
4147 * Please note that C<< $x->accuracy() >> respective C<< $x->precision() >>
4148 return eventually defined global A or P, when C<< $x >>'s A or P is not
4151 =item Creating numbers
4153 * When you create a number, you can give the desired A or P via:
4154 $x = Math::BigInt->new($number,$A,$P);
4155 * Only one of A or P can be defined, otherwise the result is NaN
4156 * If no A or P is give ($x = Math::BigInt->new($number) form), then the
4157 globals (if set) will be used. Thus changing the global defaults later on
4158 will not change the A or P of previously created numbers (i.e., A and P of
4159 $x will be what was in effect when $x was created)
4160 * If given undef for A and P, B<no> rounding will occur, and the globals will
4161 B<not> be used. This is used by subclasses to create numbers without
4162 suffering rounding in the parent. Thus a subclass is able to have its own
4163 globals enforced upon creation of a number by using
4164 C<< $x = Math::BigInt->new($number,undef,undef) >>:
4166 use Math::BigInt::SomeSubclass;
4169 Math::BigInt->accuracy(2);
4170 Math::BigInt::SomeSubClass->accuracy(3);
4171 $x = Math::BigInt::SomeSubClass->new(1234);
4173 $x is now 1230, and not 1200. A subclass might choose to implement
4174 this otherwise, e.g. falling back to the parent's A and P.
4178 * If A or P are enabled/defined, they are used to round the result of each
4179 operation according to the rules below
4180 * Negative P is ignored in Math::BigInt, since BigInts never have digits
4181 after the decimal point
4182 * Math::BigFloat uses Math::BigInt internally, but setting A or P inside
4183 Math::BigInt as globals does not tamper with the parts of a BigFloat.
4184 A flag is used to mark all Math::BigFloat numbers as 'never round'.
4188 * It only makes sense that a number has only one of A or P at a time.
4189 If you set either A or P on one object, or globally, the other one will
4190 be automatically cleared.
4191 * If two objects are involved in an operation, and one of them has A in
4192 effect, and the other P, this results in an error (NaN).
4193 * A takes precedence over P (Hint: A comes before P).
4194 If neither of them is defined, nothing is used, i.e. the result will have
4195 as many digits as it can (with an exception for fdiv/fsqrt) and will not
4197 * There is another setting for fdiv() (and thus for fsqrt()). If neither of
4198 A or P is defined, fdiv() will use a fallback (F) of $div_scale digits.
4199 If either the dividend's or the divisor's mantissa has more digits than
4200 the value of F, the higher value will be used instead of F.
4201 This is to limit the digits (A) of the result (just consider what would
4202 happen with unlimited A and P in the case of 1/3 :-)
4203 * fdiv will calculate (at least) 4 more digits than required (determined by
4204 A, P or F), and, if F is not used, round the result
4205 (this will still fail in the case of a result like 0.12345000000001 with A
4206 or P of 5, but this can not be helped - or can it?)
4207 * Thus you can have the math done by on Math::Big* class in two modi:
4208 + never round (this is the default):
4209 This is done by setting A and P to undef. No math operation
4210 will round the result, with fdiv() and fsqrt() as exceptions to guard
4211 against overflows. You must explicitly call bround(), bfround() or
4212 round() (the latter with parameters).
4213 Note: Once you have rounded a number, the settings will 'stick' on it
4214 and 'infect' all other numbers engaged in math operations with it, since
4215 local settings have the highest precedence. So, to get SaferRound[tm],
4216 use a copy() before rounding like this:
4218 $x = Math::BigFloat->new(12.34);
4219 $y = Math::BigFloat->new(98.76);
4220 $z = $x * $y; # 1218.6984
4221 print $x->copy()->fround(3); # 12.3 (but A is now 3!)
4222 $z = $x * $y; # still 1218.6984, without
4223 # copy would have been 1210!
4225 + round after each op:
4226 After each single operation (except for testing like is_zero()), the
4227 method round() is called and the result is rounded appropriately. By
4228 setting proper values for A and P, you can have all-the-same-A or
4229 all-the-same-P modes. For example, Math::Currency might set A to undef,
4230 and P to -2, globally.
4232 ?Maybe an extra option that forbids local A & P settings would be in order,
4233 ?so that intermediate rounding does not 'poison' further math?
4235 =item Overriding globals
4237 * you will be able to give A, P and R as an argument to all the calculation
4238 routines; the second parameter is A, the third one is P, and the fourth is
4239 R (shift right by one for binary operations like badd). P is used only if
4240 the first parameter (A) is undefined. These three parameters override the
4241 globals in the order detailed as follows, i.e. the first defined value
4243 (local: per object, global: global default, parameter: argument to sub)
4246 + local A (if defined on both of the operands: smaller one is taken)
4247 + local P (if defined on both of the operands: bigger one is taken)
4251 * fsqrt() will hand its arguments to fdiv(), as it used to, only now for two
4252 arguments (A and P) instead of one
4254 =item Local settings
4256 * You can set A or P locally by using C<< $x->accuracy() >> or
4257 C<< $x->precision() >>
4258 and thus force different A and P for different objects/numbers.
4259 * Setting A or P this way immediately rounds $x to the new value.
4260 * C<< $x->accuracy() >> clears C<< $x->precision() >>, and vice versa.
4264 * the rounding routines will use the respective global or local settings.
4265 fround()/bround() is for accuracy rounding, while ffround()/bfround()
4267 * the two rounding functions take as the second parameter one of the
4268 following rounding modes (R):
4269 'even', 'odd', '+inf', '-inf', 'zero', 'trunc', 'common'
4270 * you can set/get the global R by using C<< Math::SomeClass->round_mode() >>
4271 or by setting C<< $Math::SomeClass::round_mode >>
4272 * after each operation, C<< $result->round() >> is called, and the result may
4273 eventually be rounded (that is, if A or P were set either locally,
4274 globally or as parameter to the operation)
4275 * to manually round a number, call C<< $x->round($A,$P,$round_mode); >>
4276 this will round the number by using the appropriate rounding function
4277 and then normalize it.
4278 * rounding modifies the local settings of the number:
4280 $x = Math::BigFloat->new(123.456);
4284 Here 4 takes precedence over 5, so 123.5 is the result and $x->accuracy()
4285 will be 4 from now on.
4287 =item Default values
4296 * The defaults are set up so that the new code gives the same results as
4297 the old code (except in a few cases on fdiv):
4298 + Both A and P are undefined and thus will not be used for rounding
4299 after each operation.
4300 + round() is thus a no-op, unless given extra parameters A and P
4304 =head1 Infinity and Not a Number
4306 While BigInt has extensive handling of inf and NaN, certain quirks remain.
4312 These perl routines currently (as of Perl v.5.8.6) cannot handle passed
4315 te@linux:~> perl -wle 'print 2 ** 3333'
4317 te@linux:~> perl -wle 'print 2 ** 3333 == 2 ** 3333'
4319 te@linux:~> perl -wle 'print oct(2 ** 3333)'
4321 te@linux:~> perl -wle 'print hex(2 ** 3333)'
4322 Illegal hexadecimal digit 'i' ignored at -e line 1.
4325 The same problems occur if you pass them Math::BigInt->binf() objects. Since
4326 overloading these routines is not possible, this cannot be fixed from BigInt.
4328 =item ==, !=, <, >, <=, >= with NaNs
4330 BigInt's bcmp() routine currently returns undef to signal that a NaN was
4331 involved in a comparison. However, the overload code turns that into
4332 either 1 or '' and thus operations like C<< NaN != NaN >> might return
4337 C<< log(-inf) >> is highly weird. Since log(-x)=pi*i+log(x), then
4338 log(-inf)=pi*i+inf. However, since the imaginary part is finite, the real
4339 infinity "overshadows" it, so the number might as well just be infinity.
4340 However, the result is a complex number, and since BigInt/BigFloat can only
4341 have real numbers as results, the result is NaN.
4343 =item exp(), cos(), sin(), atan2()
4345 These all might have problems handling infinity right.
4351 The actual numbers are stored as unsigned big integers (with seperate sign).
4353 You should neither care about nor depend on the internal representation; it
4354 might change without notice. Use B<ONLY> method calls like C<< $x->sign(); >>
4355 instead relying on the internal representation.
4359 Math with the numbers is done (by default) by a module called
4360 C<Math::BigInt::Calc>. This is equivalent to saying:
4362 use Math::BigInt lib => 'Calc';
4364 You can change this by using:
4366 use Math::BigInt lib => 'BitVect';
4368 The following would first try to find Math::BigInt::Foo, then
4369 Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
4371 use Math::BigInt lib => 'Foo,Math::BigInt::Bar';
4373 Since Math::BigInt::GMP is in almost all cases faster than Calc (especially in
4374 math involving really big numbers, where it is B<much> faster), and there is
4375 no penalty if Math::BigInt::GMP is not installed, it is a good idea to always
4378 use Math::BigInt lib => 'GMP';
4380 Different low-level libraries use different formats to store the
4381 numbers. You should B<NOT> depend on the number having a specific format
4384 See the respective math library module documentation for further details.
4388 The sign is either '+', '-', 'NaN', '+inf' or '-inf'.
4390 A sign of 'NaN' is used to represent the result when input arguments are not
4391 numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively
4392 minus infinity. You will get '+inf' when dividing a positive number by 0, and
4393 '-inf' when dividing any negative number by 0.
4395 =head2 mantissa(), exponent() and parts()
4397 C<mantissa()> and C<exponent()> return the said parts of the BigInt such
4400 $m = $x->mantissa();
4401 $e = $x->exponent();
4402 $y = $m * ( 10 ** $e );
4403 print "ok\n" if $x == $y;
4405 C<< ($m,$e) = $x->parts() >> is just a shortcut that gives you both of them
4406 in one go. Both the returned mantissa and exponent have a sign.
4408 Currently, for BigInts C<$e> is always 0, except +inf and -inf, where it is
4409 C<+inf>; and for NaN, where it is C<NaN>; and for C<$x == 0>, where it is C<1>
4410 (to be compatible with Math::BigFloat's internal representation of a zero as
4413 C<$m> is currently just a copy of the original number. The relation between
4414 C<$e> and C<$m> will stay always the same, though their real values might
4421 sub bint { Math::BigInt->new(shift); }
4423 $x = Math::BigInt->bstr("1234") # string "1234"
4424 $x = "$x"; # same as bstr()
4425 $x = Math::BigInt->bneg("1234"); # BigInt "-1234"
4426 $x = Math::BigInt->babs("-12345"); # BigInt "12345"
4427 $x = Math::BigInt->bnorm("-0.00"); # BigInt "0"
4428 $x = bint(1) + bint(2); # BigInt "3"
4429 $x = bint(1) + "2"; # ditto (auto-BigIntify of "2")
4430 $x = bint(1); # BigInt "1"
4431 $x = $x + 5 / 2; # BigInt "3"
4432 $x = $x ** 3; # BigInt "27"
4433 $x *= 2; # BigInt "54"
4434 $x = Math::BigInt->new(0); # BigInt "0"
4436 $x = Math::BigInt->badd(4,5) # BigInt "9"
4437 print $x->bsstr(); # 9e+0
4439 Examples for rounding:
4444 $x = Math::BigFloat->new(123.4567);
4445 $y = Math::BigFloat->new(123.456789);
4446 Math::BigFloat->accuracy(4); # no more A than 4
4448 ok ($x->copy()->fround(),123.4); # even rounding
4449 print $x->copy()->fround(),"\n"; # 123.4
4450 Math::BigFloat->round_mode('odd'); # round to odd
4451 print $x->copy()->fround(),"\n"; # 123.5
4452 Math::BigFloat->accuracy(5); # no more A than 5
4453 Math::BigFloat->round_mode('odd'); # round to odd
4454 print $x->copy()->fround(),"\n"; # 123.46
4455 $y = $x->copy()->fround(4),"\n"; # A = 4: 123.4
4456 print "$y, ",$y->accuracy(),"\n"; # 123.4, 4
4458 Math::BigFloat->accuracy(undef); # A not important now
4459 Math::BigFloat->precision(2); # P important
4460 print $x->copy()->bnorm(),"\n"; # 123.46
4461 print $x->copy()->fround(),"\n"; # 123.46
4463 Examples for converting:
4465 my $x = Math::BigInt->new('0b1'.'01' x 123);
4466 print "bin: ",$x->as_bin()," hex:",$x->as_hex()," dec: ",$x,"\n";
4468 =head1 Autocreating constants
4470 After C<use Math::BigInt ':constant'> all the B<integer> decimal, hexadecimal
4471 and binary constants in the given scope are converted to C<Math::BigInt>.
4472 This conversion happens at compile time.
4476 perl -MMath::BigInt=:constant -e 'print 2**100,"\n"'
4478 prints the integer value of C<2**100>. Note that without conversion of
4479 constants the expression 2**100 will be calculated as perl scalar.
4481 Please note that strings and floating point constants are not affected,
4484 use Math::BigInt qw/:constant/;
4486 $x = 1234567890123456789012345678901234567890
4487 + 123456789123456789;
4488 $y = '1234567890123456789012345678901234567890'
4489 + '123456789123456789';
4491 do not work. You need an explicit Math::BigInt->new() around one of the
4492 operands. You should also quote large constants to protect loss of precision:
4496 $x = Math::BigInt->new('1234567889123456789123456789123456789');
4498 Without the quotes Perl would convert the large number to a floating point
4499 constant at compile time and then hand the result to BigInt, which results in
4500 an truncated result or a NaN.
4502 This also applies to integers that look like floating point constants:
4504 use Math::BigInt ':constant';
4506 print ref(123e2),"\n";
4507 print ref(123.2e2),"\n";
4509 will print nothing but newlines. Use either L<bignum> or L<Math::BigFloat>
4510 to get this to work.
4514 Using the form $x += $y; etc over $x = $x + $y is faster, since a copy of $x
4515 must be made in the second case. For long numbers, the copy can eat up to 20%
4516 of the work (in the case of addition/subtraction, less for
4517 multiplication/division). If $y is very small compared to $x, the form
4518 $x += $y is MUCH faster than $x = $x + $y since making the copy of $x takes
4519 more time then the actual addition.
4521 With a technique called copy-on-write, the cost of copying with overload could
4522 be minimized or even completely avoided. A test implementation of COW did show
4523 performance gains for overloaded math, but introduced a performance loss due
4524 to a constant overhead for all other operations. So Math::BigInt does currently
4527 The rewritten version of this module (vs. v0.01) is slower on certain
4528 operations, like C<new()>, C<bstr()> and C<numify()>. The reason are that it
4529 does now more work and handles much more cases. The time spent in these
4530 operations is usually gained in the other math operations so that code on
4531 the average should get (much) faster. If they don't, please contact the author.
4533 Some operations may be slower for small numbers, but are significantly faster
4534 for big numbers. Other operations are now constant (O(1), like C<bneg()>,
4535 C<babs()> etc), instead of O(N) and thus nearly always take much less time.
4536 These optimizations were done on purpose.
4538 If you find the Calc module to slow, try to install any of the replacement
4539 modules and see if they help you.
4541 =head2 Alternative math libraries
4543 You can use an alternative library to drive Math::BigInt via:
4545 use Math::BigInt lib => 'Module';
4547 See L<MATH LIBRARY> for more information.
4549 For more benchmark results see L<http://bloodgate.com/perl/benchmarks.html>.
4553 =head1 Subclassing Math::BigInt
4555 The basic design of Math::BigInt allows simple subclasses with very little
4556 work, as long as a few simple rules are followed:
4562 The public API must remain consistent, i.e. if a sub-class is overloading
4563 addition, the sub-class must use the same name, in this case badd(). The
4564 reason for this is that Math::BigInt is optimized to call the object methods
4569 The private object hash keys like C<$x->{sign}> may not be changed, but
4570 additional keys can be added, like C<$x->{_custom}>.
4574 Accessor functions are available for all existing object hash keys and should
4575 be used instead of directly accessing the internal hash keys. The reason for
4576 this is that Math::BigInt itself has a pluggable interface which permits it
4577 to support different storage methods.
4581 More complex sub-classes may have to replicate more of the logic internal of
4582 Math::BigInt if they need to change more basic behaviors. A subclass that
4583 needs to merely change the output only needs to overload C<bstr()>.
4585 All other object methods and overloaded functions can be directly inherited
4586 from the parent class.
4588 At the very minimum, any subclass will need to provide its own C<new()> and can
4589 store additional hash keys in the object. There are also some package globals
4590 that must be defined, e.g.:
4594 $precision = -2; # round to 2 decimal places
4595 $round_mode = 'even';
4598 Additionally, you might want to provide the following two globals to allow
4599 auto-upgrading and auto-downgrading to work correctly:
4604 This allows Math::BigInt to correctly retrieve package globals from the
4605 subclass, like C<$SubClass::precision>. See t/Math/BigInt/Subclass.pm or
4606 t/Math/BigFloat/SubClass.pm completely functional subclass examples.
4612 in your subclass to automatically inherit the overloading from the parent. If
4613 you like, you can change part of the overloading, look at Math::String for an
4618 When used like this:
4620 use Math::BigInt upgrade => 'Foo::Bar';
4622 certain operations will 'upgrade' their calculation and thus the result to
4623 the class Foo::Bar. Usually this is used in conjunction with Math::BigFloat:
4625 use Math::BigInt upgrade => 'Math::BigFloat';
4627 As a shortcut, you can use the module C<bignum>:
4631 Also good for oneliners:
4633 perl -Mbignum -le 'print 2 ** 255'
4635 This makes it possible to mix arguments of different classes (as in 2.5 + 2)
4636 as well es preserve accuracy (as in sqrt(3)).
4638 Beware: This feature is not fully implemented yet.
4642 The following methods upgrade themselves unconditionally; that is if upgrade
4643 is in effect, they will always hand up their work:
4657 Beware: This list is not complete.
4659 All other methods upgrade themselves only when one (or all) of their
4660 arguments are of the class mentioned in $upgrade (This might change in later
4661 versions to a more sophisticated scheme):
4665 C<Math::BigInt> exports nothing by default, but can export the following methods:
4672 Some things might not work as you expect them. Below is documented what is
4673 known to be troublesome:
4677 =item bstr(), bsstr() and 'cmp'
4679 Both C<bstr()> and C<bsstr()> as well as automated stringify via overload now
4680 drop the leading '+'. The old code would return '+3', the new returns '3'.
4681 This is to be consistent with Perl and to make C<cmp> (especially with
4682 overloading) to work as you expect. It also solves problems with C<Test.pm>,
4683 because its C<ok()> uses 'eq' internally.
4685 Mark Biggar said, when asked about to drop the '+' altogether, or make only
4688 I agree (with the first alternative), don't add the '+' on positive
4689 numbers. It's not as important anymore with the new internal
4690 form for numbers. It made doing things like abs and neg easier,
4691 but those have to be done differently now anyway.
4693 So, the following examples will now work all as expected:
4696 BEGIN { plan tests => 1 }
4699 my $x = new Math::BigInt 3*3;
4700 my $y = new Math::BigInt 3*3;
4703 print "$x eq 9" if $x eq $y;
4704 print "$x eq 9" if $x eq '9';
4705 print "$x eq 9" if $x eq 3*3;
4707 Additionally, the following still works:
4709 print "$x == 9" if $x == $y;
4710 print "$x == 9" if $x == 9;
4711 print "$x == 9" if $x == 3*3;
4713 There is now a C<bsstr()> method to get the string in scientific notation aka
4714 C<1e+2> instead of C<100>. Be advised that overloaded 'eq' always uses bstr()
4715 for comparison, but Perl will represent some numbers as 100 and others
4716 as 1e+308. If in doubt, convert both arguments to Math::BigInt before
4717 comparing them as strings:
4720 BEGIN { plan tests => 3 }
4723 $x = Math::BigInt->new('1e56'); $y = 1e56;
4724 ok ($x,$y); # will fail
4725 ok ($x->bsstr(),$y); # okay
4726 $y = Math::BigInt->new($y);
4729 Alternatively, simple use C<< <=> >> for comparisons, this will get it
4730 always right. There is not yet a way to get a number automatically represented
4731 as a string that matches exactly the way Perl represents it.
4733 See also the section about L<Infinity and Not a Number> for problems in
4738 C<int()> will return (at least for Perl v5.7.1 and up) another BigInt, not a
4741 $x = Math::BigInt->new(123);
4742 $y = int($x); # BigInt 123
4743 $x = Math::BigFloat->new(123.45);
4744 $y = int($x); # BigInt 123
4746 In all Perl versions you can use C<as_number()> or C<as_int> for the same
4749 $x = Math::BigFloat->new(123.45);
4750 $y = $x->as_number(); # BigInt 123
4751 $y = $x->as_int(); # ditto
4753 This also works for other subclasses, like Math::String.
4755 If you want a real Perl scalar, use C<numify()>:
4757 $y = $x->numify(); # 123 as scalar
4759 This is seldom necessary, though, because this is done automatically, like
4760 when you access an array:
4762 $z = $array[$x]; # does work automatically
4766 The following will probably not do what you expect:
4768 $c = Math::BigInt->new(123);
4769 print $c->length(),"\n"; # prints 30
4771 It prints both the number of digits in the number and in the fraction part
4772 since print calls C<length()> in list context. Use something like:
4774 print scalar $c->length(),"\n"; # prints 3
4778 The following will probably not do what you expect:
4780 print $c->bdiv(10000),"\n";
4782 It prints both quotient and remainder since print calls C<bdiv()> in list
4783 context. Also, C<bdiv()> will modify $c, so be careful. You probably want
4786 print $c / 10000,"\n";
4787 print scalar $c->bdiv(10000),"\n"; # or if you want to modify $c
4791 The quotient is always the greatest integer less than or equal to the
4792 real-valued quotient of the two operands, and the remainder (when it is
4793 nonzero) always has the same sign as the second operand; so, for
4803 As a consequence, the behavior of the operator % agrees with the
4804 behavior of Perl's built-in % operator (as documented in the perlop
4805 manpage), and the equation
4807 $x == ($x / $y) * $y + ($x % $y)
4809 holds true for any $x and $y, which justifies calling the two return
4810 values of bdiv() the quotient and remainder. The only exception to this rule
4811 are when $y == 0 and $x is negative, then the remainder will also be
4812 negative. See below under "infinity handling" for the reasoning behind this.
4814 Perl's 'use integer;' changes the behaviour of % and / for scalars, but will
4815 not change BigInt's way to do things. This is because under 'use integer' Perl
4816 will do what the underlying C thinks is right and this is different for each
4817 system. If you need BigInt's behaving exactly like Perl's 'use integer', bug
4818 the author to implement it ;)
4820 =item infinity handling
4822 Here are some examples that explain the reasons why certain results occur while
4825 The following table shows the result of the division and the remainder, so that
4826 the equation above holds true. Some "ordinary" cases are strewn in to show more
4827 clearly the reasoning:
4829 A / B = C, R so that C * B + R = A
4830 =========================================================
4831 5 / 8 = 0, 5 0 * 8 + 5 = 5
4832 0 / 8 = 0, 0 0 * 8 + 0 = 0
4833 0 / inf = 0, 0 0 * inf + 0 = 0
4834 0 /-inf = 0, 0 0 * -inf + 0 = 0
4835 5 / inf = 0, 5 0 * inf + 5 = 5
4836 5 /-inf = 0, 5 0 * -inf + 5 = 5
4837 -5/ inf = 0, -5 0 * inf + -5 = -5
4838 -5/-inf = 0, -5 0 * -inf + -5 = -5
4839 inf/ 5 = inf, 0 inf * 5 + 0 = inf
4840 -inf/ 5 = -inf, 0 -inf * 5 + 0 = -inf
4841 inf/ -5 = -inf, 0 -inf * -5 + 0 = inf
4842 -inf/ -5 = inf, 0 inf * -5 + 0 = -inf
4843 5/ 5 = 1, 0 1 * 5 + 0 = 5
4844 -5/ -5 = 1, 0 1 * -5 + 0 = -5
4845 inf/ inf = 1, 0 1 * inf + 0 = inf
4846 -inf/-inf = 1, 0 1 * -inf + 0 = -inf
4847 inf/-inf = -1, 0 -1 * -inf + 0 = inf
4848 -inf/ inf = -1, 0 1 * -inf + 0 = -inf
4849 8/ 0 = inf, 8 inf * 0 + 8 = 8
4850 inf/ 0 = inf, inf inf * 0 + inf = inf
4853 These cases below violate the "remainder has the sign of the second of the two
4854 arguments", since they wouldn't match up otherwise.
4856 A / B = C, R so that C * B + R = A
4857 ========================================================
4858 -inf/ 0 = -inf, -inf -inf * 0 + inf = -inf
4859 -8/ 0 = -inf, -8 -inf * 0 + 8 = -8
4861 =item Modifying and =
4865 $x = Math::BigFloat->new(5);
4868 It will not do what you think, e.g. making a copy of $x. Instead it just makes
4869 a second reference to the B<same> object and stores it in $y. Thus anything
4870 that modifies $x (except overloaded operators) will modify $y, and vice versa.
4871 Or in other words, C<=> is only safe if you modify your BigInts only via
4872 overloaded math. As soon as you use a method call it breaks:
4875 print "$x, $y\n"; # prints '10, 10'
4877 If you want a true copy of $x, use:
4881 You can also chain the calls like this, this will make first a copy and then
4884 $y = $x->copy()->bmul(2);
4886 See also the documentation for overload.pm regarding C<=>.
4890 C<bpow()> (and the rounding functions) now modifies the first argument and
4891 returns it, unlike the old code which left it alone and only returned the
4892 result. This is to be consistent with C<badd()> etc. The first three will
4893 modify $x, the last one won't:
4895 print bpow($x,$i),"\n"; # modify $x
4896 print $x->bpow($i),"\n"; # ditto
4897 print $x **= $i,"\n"; # the same
4898 print $x ** $i,"\n"; # leave $x alone
4900 The form C<$x **= $y> is faster than C<$x = $x ** $y;>, though.
4902 =item Overloading -$x
4912 since overload calls C<sub($x,0,1);> instead of C<neg($x)>. The first variant
4913 needs to preserve $x since it does not know that it later will get overwritten.
4914 This makes a copy of $x and takes O(N), but $x->bneg() is O(1).
4916 =item Mixing different object types
4918 In Perl you will get a floating point value if you do one of the following:
4924 With overloaded math, only the first two variants will result in a BigFloat:
4929 $mbf = Math::BigFloat->new(5);
4930 $mbi2 = Math::BigInteger->new(5);
4931 $mbi = Math::BigInteger->new(2);
4933 # what actually gets called:
4934 $float = $mbf + $mbi; # $mbf->badd()
4935 $float = $mbf / $mbi; # $mbf->bdiv()
4936 $integer = $mbi + $mbf; # $mbi->badd()
4937 $integer = $mbi2 / $mbi; # $mbi2->bdiv()
4938 $integer = $mbi2 / $mbf; # $mbi2->bdiv()
4940 This is because math with overloaded operators follows the first (dominating)
4941 operand, and the operation of that is called and returns thus the result. So,
4942 Math::BigInt::bdiv() will always return a Math::BigInt, regardless whether
4943 the result should be a Math::BigFloat or the second operant is one.
4945 To get a Math::BigFloat you either need to call the operation manually,
4946 make sure the operands are already of the proper type or casted to that type
4947 via Math::BigFloat->new():
4949 $float = Math::BigFloat->new($mbi2) / $mbi; # = 2.5
4951 Beware of simple "casting" the entire expression, this would only convert
4952 the already computed result:
4954 $float = Math::BigFloat->new($mbi2 / $mbi); # = 2.0 thus wrong!
4956 Beware also of the order of more complicated expressions like:
4958 $integer = ($mbi2 + $mbi) / $mbf; # int / float => int
4959 $integer = $mbi2 / Math::BigFloat->new($mbi); # ditto
4961 If in doubt, break the expression into simpler terms, or cast all operands
4962 to the desired resulting type.
4964 Scalar values are a bit different, since:
4969 will both result in the proper type due to the way the overloaded math works.
4971 This section also applies to other overloaded math packages, like Math::String.
4973 One solution to you problem might be autoupgrading|upgrading. See the
4974 pragmas L<bignum>, L<bigint> and L<bigrat> for an easy way to do this.
4978 C<bsqrt()> works only good if the result is a big integer, e.g. the square
4979 root of 144 is 12, but from 12 the square root is 3, regardless of rounding
4980 mode. The reason is that the result is always truncated to an integer.
4982 If you want a better approximation of the square root, then use:
4984 $x = Math::BigFloat->new(12);
4985 Math::BigFloat->precision(0);
4986 Math::BigFloat->round_mode('even');
4987 print $x->copy->bsqrt(),"\n"; # 4
4989 Math::BigFloat->precision(2);
4990 print $x->bsqrt(),"\n"; # 3.46
4991 print $x->bsqrt(3),"\n"; # 3.464
4995 For negative numbers in base see also L<brsft|brsft>.
5001 This program is free software; you may redistribute it and/or modify it under
5002 the same terms as Perl itself.
5006 L<Math::BigFloat>, L<Math::BigRat> and L<Math::Big> as well as
5007 L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>.
5009 The pragmas L<bignum>, L<bigint> and L<bigrat> also might be of interest
5010 because they solve the autoupgrading/downgrading issue, at least partly.
5013 L<http://search.cpan.org/search?mode=module&query=Math%3A%3ABigInt> contains
5014 more documentation including a full version history, testcases, empty
5015 subclass files and benchmarks.
5019 Original code by Mark Biggar, overloaded interface by Ilya Zakharevich.
5020 Completely rewritten by Tels http://bloodgate.com in late 2000, 2001 - 2006
5021 and still at it in 2007.
5023 Many people contributed in one or more ways to the final beast, see the file
5024 CREDITS for an (incomplete) list. If you miss your name, please drop me a