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 # make cos()/sin()/atan2() "work" with BigInt's or subclasses
85 'cos' => sub { cos($_[0]->numify()) },
86 'sin' => sub { sin($_[0]->numify()) },
87 'atan2' => sub { $_[2] ?
88 atan2($_[1],$_[0]->numify()) :
89 atan2($_[0]->numify(),$_[1]) },
91 # are not yet overloadable
92 #'hex' => sub { print "hex"; $_[0]; },
93 #'oct' => sub { print "oct"; $_[0]; },
95 # log(N) is log(N, e), where e is Euler's number
96 'log' => sub { $_[0]->copy()->blog($_[1], undef); },
97 'exp' => sub { $_[0]->copy()->bexp($_[1]); },
98 'int' => sub { $_[0]->copy(); },
99 'neg' => sub { $_[0]->copy()->bneg(); },
100 'abs' => sub { $_[0]->copy()->babs(); },
101 'sqrt' => sub { $_[0]->copy()->bsqrt(); },
102 '~' => sub { $_[0]->copy()->bnot(); },
104 # for subtract it's a bit tricky to not modify b: b-a => -a+b
105 '-' => sub { my $c = $_[0]->copy; $_[2] ?
106 $c->bneg()->badd( $_[1]) :
108 '+' => sub { $_[0]->copy()->badd($_[1]); },
109 '*' => sub { $_[0]->copy()->bmul($_[1]); },
112 $_[2] ? ref($_[0])->new($_[1])->bdiv($_[0]) : $_[0]->copy->bdiv($_[1]);
115 $_[2] ? ref($_[0])->new($_[1])->bmod($_[0]) : $_[0]->copy->bmod($_[1]);
118 $_[2] ? ref($_[0])->new($_[1])->bpow($_[0]) : $_[0]->copy->bpow($_[1]);
121 $_[2] ? ref($_[0])->new($_[1])->blsft($_[0]) : $_[0]->copy->blsft($_[1]);
124 $_[2] ? ref($_[0])->new($_[1])->brsft($_[0]) : $_[0]->copy->brsft($_[1]);
127 $_[2] ? ref($_[0])->new($_[1])->band($_[0]) : $_[0]->copy->band($_[1]);
130 $_[2] ? ref($_[0])->new($_[1])->bior($_[0]) : $_[0]->copy->bior($_[1]);
133 $_[2] ? ref($_[0])->new($_[1])->bxor($_[0]) : $_[0]->copy->bxor($_[1]);
136 # can modify arg of ++ and --, so avoid a copy() for speed, but don't
137 # use $_[0]->bone(), it would modify $_[0] to be 1!
138 '++' => sub { $_[0]->binc() },
139 '--' => sub { $_[0]->bdec() },
141 # if overloaded, O(1) instead of O(N) and twice as fast for small numbers
143 # this kludge is needed for perl prior 5.6.0 since returning 0 here fails :-/
144 # v5.6.1 dumps on this: return !$_[0]->is_zero() || undef; :-(
146 $t = 1 if !$_[0]->is_zero();
150 # the original qw() does not work with the TIESCALAR below, why?
151 # Order of arguments unsignificant
152 '""' => sub { $_[0]->bstr(); },
153 '0+' => sub { $_[0]->numify(); }
156 ##############################################################################
157 # global constants, flags and accessory
159 # These vars are public, but their direct usage is not recommended, use the
160 # accessor methods instead
162 $round_mode = 'even'; # one of 'even', 'odd', '+inf', '-inf', 'zero', 'trunc' or 'common'
167 $upgrade = undef; # default is no upgrade
168 $downgrade = undef; # default is no downgrade
170 # These are internally, and not to be used from the outside at all
172 $_trap_nan = 0; # are NaNs ok? set w/ config()
173 $_trap_inf = 0; # are infs ok? set w/ config()
174 my $nan = 'NaN'; # constants for easier life
176 my $CALC = 'Math::BigInt::FastCalc'; # module to do the low level math
177 # default is FastCalc.pm
178 my $IMPORT = 0; # was import() called yet?
179 # used to make require work
180 my %WARN; # warn only once for low-level libs
181 my %CAN; # cache for $CALC->can(...)
182 my %CALLBACKS; # callbacks to notify on lib loads
183 my $EMU_LIB = 'Math/BigInt/CalcEmu.pm'; # emulate low-level math
185 ##############################################################################
186 # the old code had $rnd_mode, so we need to support it, too
189 sub TIESCALAR { my ($class) = @_; bless \$round_mode, $class; }
190 sub FETCH { return $round_mode; }
191 sub STORE { $rnd_mode = $_[0]->round_mode($_[1]); }
195 # tie to enable $rnd_mode to work transparently
196 tie $rnd_mode, 'Math::BigInt';
198 # set up some handy alias names
199 *as_int = \&as_number;
200 *is_pos = \&is_positive;
201 *is_neg = \&is_negative;
204 ##############################################################################
209 # make Class->round_mode() work
211 my $class = ref($self) || $self || __PACKAGE__;
215 if ($m !~ /^(even|odd|\+inf|\-inf|zero|trunc|common)$/)
217 require Carp; Carp::croak ("Unknown round mode '$m'");
219 return ${"${class}::round_mode"} = $m;
221 ${"${class}::round_mode"};
227 # make Class->upgrade() work
229 my $class = ref($self) || $self || __PACKAGE__;
230 # need to set new value?
233 return ${"${class}::upgrade"} = $_[0];
235 ${"${class}::upgrade"};
241 # make Class->downgrade() work
243 my $class = ref($self) || $self || __PACKAGE__;
244 # need to set new value?
247 return ${"${class}::downgrade"} = $_[0];
249 ${"${class}::downgrade"};
255 # make Class->div_scale() work
257 my $class = ref($self) || $self || __PACKAGE__;
262 require Carp; Carp::croak ('div_scale must be greater than zero');
264 ${"${class}::div_scale"} = $_[0];
266 ${"${class}::div_scale"};
271 # $x->accuracy($a); ref($x) $a
272 # $x->accuracy(); ref($x)
273 # Class->accuracy(); class
274 # Class->accuracy($a); class $a
277 my $class = ref($x) || $x || __PACKAGE__;
280 # need to set new value?
284 # convert objects to scalars to avoid deep recursion. If object doesn't
285 # have numify(), then hopefully it will have overloading for int() and
286 # boolean test without wandering into a deep recursion path...
287 $a = $a->numify() if ref($a) && $a->can('numify');
291 # also croak on non-numerical
295 Carp::croak ('Argument to accuracy must be greater than zero');
299 require Carp; Carp::croak ('Argument to accuracy must be an integer');
304 # $object->accuracy() or fallback to global
305 $x->bround($a) if $a; # not for undef, 0
306 $x->{_a} = $a; # set/overwrite, even if not rounded
307 delete $x->{_p}; # clear P
308 $a = ${"${class}::accuracy"} unless defined $a; # proper return value
312 ${"${class}::accuracy"} = $a; # set global A
313 ${"${class}::precision"} = undef; # clear global P
315 return $a; # shortcut
319 # $object->accuracy() or fallback to global
320 $a = $x->{_a} if ref($x);
321 # but don't return global undef, when $x's accuracy is 0!
322 $a = ${"${class}::accuracy"} if !defined $a;
328 # $x->precision($p); ref($x) $p
329 # $x->precision(); ref($x)
330 # Class->precision(); class
331 # Class->precision($p); class $p
334 my $class = ref($x) || $x || __PACKAGE__;
340 # convert objects to scalars to avoid deep recursion. If object doesn't
341 # have numify(), then hopefully it will have overloading for int() and
342 # boolean test without wandering into a deep recursion path...
343 $p = $p->numify() if ref($p) && $p->can('numify');
344 if ((defined $p) && (int($p) != $p))
346 require Carp; Carp::croak ('Argument to precision must be an integer');
350 # $object->precision() or fallback to global
351 $x->bfround($p) if $p; # not for undef, 0
352 $x->{_p} = $p; # set/overwrite, even if not rounded
353 delete $x->{_a}; # clear A
354 $p = ${"${class}::precision"} unless defined $p; # proper return value
358 ${"${class}::precision"} = $p; # set global P
359 ${"${class}::accuracy"} = undef; # clear global A
361 return $p; # shortcut
365 # $object->precision() or fallback to global
366 $p = $x->{_p} if ref($x);
367 # but don't return global undef, when $x's precision is 0!
368 $p = ${"${class}::precision"} if !defined $p;
374 # return (or set) configuration data as hash ref
375 my $class = shift || 'Math::BigInt';
378 if (@_ > 1 || (@_ == 1 && (ref($_[0]) eq 'HASH')))
380 # try to set given options as arguments from hash
383 if (ref($args) ne 'HASH')
387 # these values can be "set"
391 upgrade downgrade precision accuracy round_mode div_scale/
394 $set_args->{$key} = $args->{$key} if exists $args->{$key};
395 delete $args->{$key};
400 Carp::croak ("Illegal key(s) '",
401 join("','",keys %$args),"' passed to $class\->config()");
403 foreach my $key (keys %$set_args)
405 if ($key =~ /^trap_(inf|nan)\z/)
407 ${"${class}::_trap_$1"} = ($set_args->{"trap_$1"} ? 1 : 0);
410 # use a call instead of just setting the $variable to check argument
411 $class->$key($set_args->{$key});
415 # now return actual configuration
419 lib_version => ${"${CALC}::VERSION"},
421 trap_nan => ${"${class}::_trap_nan"},
422 trap_inf => ${"${class}::_trap_inf"},
423 version => ${"${class}::VERSION"},
426 upgrade downgrade precision accuracy round_mode div_scale
429 $cfg->{$key} = ${"${class}::$key"};
431 if (@_ == 1 && (ref($_[0]) ne 'HASH'))
433 # calls of the style config('lib') return just this value
434 return $cfg->{$_[0]};
441 # select accuracy parameter based on precedence,
442 # used by bround() and bfround(), may return undef for scale (means no op)
443 my ($x,$scale,$mode) = @_;
445 $scale = $x->{_a} unless defined $scale;
450 $scale = ${ $class . '::accuracy' } unless defined $scale;
451 $mode = ${ $class . '::round_mode' } unless defined $mode;
458 # select precision parameter based on precedence,
459 # used by bround() and bfround(), may return undef for scale (means no op)
460 my ($x,$scale,$mode) = @_;
462 $scale = $x->{_p} unless defined $scale;
467 $scale = ${ $class . '::precision' } unless defined $scale;
468 $mode = ${ $class . '::round_mode' } unless defined $mode;
473 ##############################################################################
478 # if two arguments, the first one is the class to "swallow" subclasses
482 sign => $_[1]->{sign},
483 value => $CALC->_copy($_[1]->{value}),
486 $self->{_a} = $_[1]->{_a} if defined $_[1]->{_a};
487 $self->{_p} = $_[1]->{_p} if defined $_[1]->{_p};
492 sign => $_[0]->{sign},
493 value => $CALC->_copy($_[0]->{value}),
496 $self->{_a} = $_[0]->{_a} if defined $_[0]->{_a};
497 $self->{_p} = $_[0]->{_p} if defined $_[0]->{_p};
503 # create a new BigInt object from a string or another BigInt object.
504 # see hash keys documented at top
506 # the argument could be an object, so avoid ||, && etc on it, this would
507 # cause costly overloaded code to be called. The only allowed ops are
510 my ($class,$wanted,$a,$p,$r) = @_;
512 # avoid numify-calls by not using || on $wanted!
513 return $class->bzero($a,$p) if !defined $wanted; # default to 0
514 return $class->copy($wanted,$a,$p,$r)
515 if ref($wanted) && $wanted->isa($class); # MBI or subclass
517 $class->import() if $IMPORT == 0; # make require work
519 my $self = bless {}, $class;
521 # shortcut for "normal" numbers
522 if ((!ref $wanted) && ($wanted =~ /^([+-]?)[1-9][0-9]*\z/))
524 $self->{sign} = $1 || '+';
526 if ($wanted =~ /^[+-]/)
528 # remove sign without touching wanted to make it work with constants
529 my $t = $wanted; $t =~ s/^[+-]//;
530 $self->{value} = $CALC->_new($t);
534 $self->{value} = $CALC->_new($wanted);
537 if ( (defined $a) || (defined $p)
538 || (defined ${"${class}::precision"})
539 || (defined ${"${class}::accuracy"})
542 $self->round($a,$p,$r) unless (@_ == 4 && !defined $a && !defined $p);
547 # handle '+inf', '-inf' first
548 if ($wanted =~ /^[+-]?inf\z/)
550 $self->{sign} = $wanted; # set a default sign for bstr()
551 return $self->binf($wanted);
553 # split str in m mantissa, e exponent, i integer, f fraction, v value, s sign
554 my ($mis,$miv,$mfv,$es,$ev) = _split($wanted);
559 require Carp; Carp::croak("$wanted is not a number in $class");
561 $self->{value} = $CALC->_zero();
562 $self->{sign} = $nan;
567 # _from_hex or _from_bin
568 $self->{value} = $mis->{value};
569 $self->{sign} = $mis->{sign};
570 return $self; # throw away $mis
572 # make integer from mantissa by adjusting exp, then convert to bigint
573 $self->{sign} = $$mis; # store sign
574 $self->{value} = $CALC->_zero(); # for all the NaN cases
575 my $e = int("$$es$$ev"); # exponent (avoid recursion)
578 my $diff = $e - CORE::length($$mfv);
579 if ($diff < 0) # Not integer
583 require Carp; Carp::croak("$wanted not an integer in $class");
586 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
587 $self->{sign} = $nan;
591 # adjust fraction and add it to value
592 #print "diff > 0 $$miv\n";
593 $$miv = $$miv . ($$mfv . '0' x $diff);
598 if ($$mfv ne '') # e <= 0
600 # fraction and negative/zero E => NOI
603 require Carp; Carp::croak("$wanted not an integer in $class");
605 #print "NOI 2 \$\$mfv '$$mfv'\n";
606 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
607 $self->{sign} = $nan;
611 # xE-y, and empty mfv
614 if ($$miv !~ s/0{$e}$//) # can strip so many zero's?
618 require Carp; Carp::croak("$wanted not an integer in $class");
621 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
622 $self->{sign} = $nan;
626 $self->{sign} = '+' if $$miv eq '0'; # normalize -0 => +0
627 $self->{value} = $CALC->_new($$miv) if $self->{sign} =~ /^[+-]$/;
628 # if any of the globals is set, use them to round and store them inside $self
629 # do not round for new($x,undef,undef) since that is used by MBF to signal
631 $self->round($a,$p,$r) unless @_ == 4 && !defined $a && !defined $p;
637 # create a bigint 'NaN', if given a BigInt, set it to 'NaN'
639 $self = $class if !defined $self;
642 my $c = $self; $self = {}; bless $self, $c;
645 if (${"${class}::_trap_nan"})
648 Carp::croak ("Tried to set $self to NaN in $class\::bnan()");
650 $self->import() if $IMPORT == 0; # make require work
651 return if $self->modify('bnan');
652 if ($self->can('_bnan'))
654 # use subclass to initialize
659 # otherwise do our own thing
660 $self->{value} = $CALC->_zero();
662 $self->{sign} = $nan;
663 delete $self->{_a}; delete $self->{_p}; # rounding NaN is silly
669 # create a bigint '+-inf', if given a BigInt, set it to '+-inf'
670 # the sign is either '+', or if given, used from there
672 my $sign = shift; $sign = '+' if !defined $sign || $sign !~ /^-(inf)?$/;
673 $self = $class if !defined $self;
676 my $c = $self; $self = {}; bless $self, $c;
679 if (${"${class}::_trap_inf"})
682 Carp::croak ("Tried to set $self to +-inf in $class\::binf()");
684 $self->import() if $IMPORT == 0; # make require work
685 return if $self->modify('binf');
686 if ($self->can('_binf'))
688 # use subclass to initialize
693 # otherwise do our own thing
694 $self->{value} = $CALC->_zero();
696 $sign = $sign . 'inf' if $sign !~ /inf$/; # - => -inf
697 $self->{sign} = $sign;
698 ($self->{_a},$self->{_p}) = @_; # take over requested rounding
704 # create a bigint '+0', if given a BigInt, set it to 0
706 $self = __PACKAGE__ if !defined $self;
710 my $c = $self; $self = {}; bless $self, $c;
712 $self->import() if $IMPORT == 0; # make require work
713 return if $self->modify('bzero');
715 if ($self->can('_bzero'))
717 # use subclass to initialize
722 # otherwise do our own thing
723 $self->{value} = $CALC->_zero();
730 # call like: $x->bzero($a,$p,$r,$y);
731 ($self,$self->{_a},$self->{_p}) = $self->_find_round_parameters(@_);
736 if ( (!defined $self->{_a}) || (defined $_[0] && $_[0] > $self->{_a}));
738 if ( (!defined $self->{_p}) || (defined $_[1] && $_[1] > $self->{_p}));
746 # create a bigint '+1' (or -1 if given sign '-'),
747 # if given a BigInt, set it to +1 or -1, respectively
749 my $sign = shift; $sign = '+' if !defined $sign || $sign ne '-';
750 $self = $class if !defined $self;
754 my $c = $self; $self = {}; bless $self, $c;
756 $self->import() if $IMPORT == 0; # make require work
757 return if $self->modify('bone');
759 if ($self->can('_bone'))
761 # use subclass to initialize
766 # otherwise do our own thing
767 $self->{value} = $CALC->_one();
769 $self->{sign} = $sign;
774 # call like: $x->bone($sign,$a,$p,$r,$y);
775 ($self,$self->{_a},$self->{_p}) = $self->_find_round_parameters(@_);
779 # call like: $x->bone($sign,$a,$p,$r);
781 if ( (!defined $self->{_a}) || (defined $_[0] && $_[0] > $self->{_a}));
783 if ( (!defined $self->{_p}) || (defined $_[1] && $_[1] > $self->{_p}));
789 ##############################################################################
790 # string conversation
794 # (ref to BFLOAT or num_str ) return num_str
795 # Convert number from internal format to scientific string format.
796 # internal format is always normalized (no leading zeros, "-0E0" => "+0E0")
797 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
799 if ($x->{sign} !~ /^[+-]$/)
801 return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
804 my ($m,$e) = $x->parts();
805 #$m->bstr() . 'e+' . $e->bstr(); # e can only be positive in BigInt
806 # 'e+' because E can only be positive in BigInt
807 $m->bstr() . 'e+' . $CALC->_str($e->{value});
812 # make a string from bigint object
813 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
815 if ($x->{sign} !~ /^[+-]$/)
817 return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
820 my $es = ''; $es = $x->{sign} if $x->{sign} eq '-';
821 $es.$CALC->_str($x->{value});
826 # Make a "normal" scalar from a BigInt object
827 my $x = shift; $x = $class->new($x) unless ref $x;
829 return $x->bstr() if $x->{sign} !~ /^[+-]$/;
830 my $num = $CALC->_num($x->{value});
831 return -$num if $x->{sign} eq '-';
835 ##############################################################################
836 # public stuff (usually prefixed with "b")
840 # return the sign of the number: +/-/-inf/+inf/NaN
841 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
846 sub _find_round_parameters
848 # After any operation or when calling round(), the result is rounded by
849 # regarding the A & P from arguments, local parameters, or globals.
851 # !!!!!!! If you change this, remember to change round(), too! !!!!!!!!!!
853 # This procedure finds the round parameters, but it is for speed reasons
854 # duplicated in round. Otherwise, it is tested by the testsuite and used
857 # returns ($self) or ($self,$a,$p,$r) - sets $self to NaN of both A and P
858 # were requested/defined (locally or globally or both)
860 my ($self,$a,$p,$r,@args) = @_;
861 # $a accuracy, if given by caller
862 # $p precision, if given by caller
863 # $r round_mode, if given by caller
864 # @args all 'other' arguments (0 for unary, 1 for binary ops)
866 my $c = ref($self); # find out class of argument(s)
869 # convert to normal scalar for speed and correctness in inner parts
870 $a = $a->can('numify') ? $a->numify() : "$a" if defined $a && ref($a);
871 $p = $p->can('numify') ? $p->numify() : "$p" if defined $p && ref($p);
873 # now pick $a or $p, but only if we have got "arguments"
876 foreach ($self,@args)
878 # take the defined one, or if both defined, the one that is smaller
879 $a = $_->{_a} if (defined $_->{_a}) && (!defined $a || $_->{_a} < $a);
884 # even if $a is defined, take $p, to signal error for both defined
885 foreach ($self,@args)
887 # take the defined one, or if both defined, the one that is bigger
889 $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} > $p);
892 # if still none defined, use globals (#2)
893 $a = ${"$c\::accuracy"} unless defined $a;
894 $p = ${"$c\::precision"} unless defined $p;
896 # A == 0 is useless, so undef it to signal no rounding
897 $a = undef if defined $a && $a == 0;
900 return ($self) unless defined $a || defined $p; # early out
902 # set A and set P is an fatal error
903 return ($self->bnan()) if defined $a && defined $p; # error
905 $r = ${"$c\::round_mode"} unless defined $r;
906 if ($r !~ /^(even|odd|\+inf|\-inf|zero|trunc|common)$/)
908 require Carp; Carp::croak ("Unknown round mode '$r'");
916 # Round $self according to given parameters, or given second argument's
917 # parameters or global defaults
919 # for speed reasons, _find_round_parameters is embeded here:
921 my ($self,$a,$p,$r,@args) = @_;
922 # $a accuracy, if given by caller
923 # $p precision, if given by caller
924 # $r round_mode, if given by caller
925 # @args all 'other' arguments (0 for unary, 1 for binary ops)
927 my $c = ref($self); # find out class of argument(s)
930 # now pick $a or $p, but only if we have got "arguments"
933 foreach ($self,@args)
935 # take the defined one, or if both defined, the one that is smaller
936 $a = $_->{_a} if (defined $_->{_a}) && (!defined $a || $_->{_a} < $a);
941 # even if $a is defined, take $p, to signal error for both defined
942 foreach ($self,@args)
944 # take the defined one, or if both defined, the one that is bigger
946 $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} > $p);
949 # if still none defined, use globals (#2)
950 $a = ${"$c\::accuracy"} unless defined $a;
951 $p = ${"$c\::precision"} unless defined $p;
953 # A == 0 is useless, so undef it to signal no rounding
954 $a = undef if defined $a && $a == 0;
957 return $self unless defined $a || defined $p; # early out
959 # set A and set P is an fatal error
960 return $self->bnan() if defined $a && defined $p;
962 $r = ${"$c\::round_mode"} unless defined $r;
963 if ($r !~ /^(even|odd|\+inf|\-inf|zero|trunc|common)$/)
965 require Carp; Carp::croak ("Unknown round mode '$r'");
968 # now round, by calling either fround or ffround:
971 $self->bround($a,$r) if !defined $self->{_a} || $self->{_a} >= $a;
973 else # both can't be undefined due to early out
975 $self->bfround($p,$r) if !defined $self->{_p} || $self->{_p} <= $p;
977 # bround() or bfround() already callled bnorm() if nec.
983 # (numstr or BINT) return BINT
984 # Normalize number -- no-op here
985 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
991 # (BINT or num_str) return BINT
992 # make number absolute, or return absolute BINT from string
993 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
995 return $x if $x->modify('babs');
996 # post-normalized abs for internal use (does nothing for NaN)
997 $x->{sign} =~ s/^-/+/;
1003 # (BINT or num_str) return BINT
1004 # negate number or make a negated number from string
1005 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1007 return $x if $x->modify('bneg');
1009 # for +0 dont negate (to have always normalized +0). Does nothing for 'NaN'
1010 $x->{sign} =~ tr/+-/-+/ unless ($x->{sign} eq '+' && $CALC->_is_zero($x->{value}));
1016 # Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort)
1017 # (BINT or num_str, BINT or num_str) return cond_code
1020 my ($self,$x,$y) = (ref($_[0]),@_);
1022 # objectify is costly, so avoid it
1023 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1025 ($self,$x,$y) = objectify(2,@_);
1028 return $upgrade->bcmp($x,$y) if defined $upgrade &&
1029 ((!$x->isa($self)) || (!$y->isa($self)));
1031 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1033 # handle +-inf and NaN
1034 return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1035 return 0 if $x->{sign} eq $y->{sign} && $x->{sign} =~ /^[+-]inf$/;
1036 return +1 if $x->{sign} eq '+inf';
1037 return -1 if $x->{sign} eq '-inf';
1038 return -1 if $y->{sign} eq '+inf';
1041 # check sign for speed first
1042 return 1 if $x->{sign} eq '+' && $y->{sign} eq '-'; # does also 0 <=> -y
1043 return -1 if $x->{sign} eq '-' && $y->{sign} eq '+'; # does also -x <=> 0
1045 # have same sign, so compare absolute values. Don't make tests for zero here
1046 # because it's actually slower than testin in Calc (especially w/ Pari et al)
1048 # post-normalized compare for internal use (honors signs)
1049 if ($x->{sign} eq '+')
1051 # $x and $y both > 0
1052 return $CALC->_acmp($x->{value},$y->{value});
1056 $CALC->_acmp($y->{value},$x->{value}); # swaped acmp (lib returns 0,1,-1)
1061 # Compares 2 values, ignoring their signs.
1062 # Returns one of undef, <0, =0, >0. (suitable for sort)
1063 # (BINT, BINT) return cond_code
1066 my ($self,$x,$y) = (ref($_[0]),@_);
1067 # objectify is costly, so avoid it
1068 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1070 ($self,$x,$y) = objectify(2,@_);
1073 return $upgrade->bacmp($x,$y) if defined $upgrade &&
1074 ((!$x->isa($self)) || (!$y->isa($self)));
1076 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1078 # handle +-inf and NaN
1079 return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1080 return 0 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} =~ /^[+-]inf$/;
1081 return 1 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} !~ /^[+-]inf$/;
1084 $CALC->_acmp($x->{value},$y->{value}); # lib does only 0,1,-1
1089 # add second arg (BINT or string) to first (BINT) (modifies first)
1090 # return result as BINT
1093 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1094 # objectify is costly, so avoid it
1095 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1097 ($self,$x,$y,@r) = objectify(2,@_);
1100 return $x if $x->modify('badd');
1101 return $upgrade->badd($upgrade->new($x),$upgrade->new($y),@r) if defined $upgrade &&
1102 ((!$x->isa($self)) || (!$y->isa($self)));
1104 $r[3] = $y; # no push!
1105 # inf and NaN handling
1106 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1109 return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1111 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1113 # +inf++inf or -inf+-inf => same, rest is NaN
1114 return $x if $x->{sign} eq $y->{sign};
1117 # +-inf + something => +inf
1118 # something +-inf => +-inf
1119 $x->{sign} = $y->{sign}, return $x if $y->{sign} =~ /^[+-]inf$/;
1123 my ($sx, $sy) = ( $x->{sign}, $y->{sign} ); # get signs
1127 $x->{value} = $CALC->_add($x->{value},$y->{value}); # same sign, abs add
1131 my $a = $CALC->_acmp ($y->{value},$x->{value}); # absolute compare
1134 $x->{value} = $CALC->_sub($y->{value},$x->{value},1); # abs sub w/ swap
1139 # speedup, if equal, set result to 0
1140 $x->{value} = $CALC->_zero();
1145 $x->{value} = $CALC->_sub($x->{value}, $y->{value}); # abs sub
1153 # (BINT or num_str, BINT or num_str) return BINT
1154 # subtract second arg from first, modify first
1157 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1159 # objectify is costly, so avoid it
1160 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1162 ($self,$x,$y,@r) = objectify(2,@_);
1165 return $x if $x->modify('bsub');
1167 return $upgrade->new($x)->bsub($upgrade->new($y),@r) if defined $upgrade &&
1168 ((!$x->isa($self)) || (!$y->isa($self)));
1170 return $x->round(@r) if $y->is_zero();
1172 # To correctly handle the lone special case $x->bsub($x), we note the sign
1173 # of $x, then flip the sign from $y, and if the sign of $x did change, too,
1174 # then we caught the special case:
1175 my $xsign = $x->{sign};
1176 $y->{sign} =~ tr/+\-/-+/; # does nothing for NaN
1177 if ($xsign ne $x->{sign})
1179 # special case of $x->bsub($x) results in 0
1180 return $x->bzero(@r) if $xsign =~ /^[+-]$/;
1181 return $x->bnan(); # NaN, -inf, +inf
1183 $x->badd($y,@r); # badd does not leave internal zeros
1184 $y->{sign} =~ tr/+\-/-+/; # refix $y (does nothing for NaN)
1185 $x; # already rounded by badd() or no round nec.
1190 # increment arg by one
1191 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1192 return $x if $x->modify('binc');
1194 if ($x->{sign} eq '+')
1196 $x->{value} = $CALC->_inc($x->{value});
1197 return $x->round($a,$p,$r);
1199 elsif ($x->{sign} eq '-')
1201 $x->{value} = $CALC->_dec($x->{value});
1202 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # -1 +1 => -0 => +0
1203 return $x->round($a,$p,$r);
1205 # inf, nan handling etc
1206 $x->badd($self->bone(),$a,$p,$r); # badd does round
1211 # decrement arg by one
1212 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1213 return $x if $x->modify('bdec');
1215 if ($x->{sign} eq '-')
1218 $x->{value} = $CALC->_inc($x->{value});
1222 return $x->badd($self->bone('-'),@r) unless $x->{sign} eq '+'; # inf or NaN
1224 if ($CALC->_is_zero($x->{value}))
1227 $x->{value} = $CALC->_one(); $x->{sign} = '-'; # 0 => -1
1232 $x->{value} = $CALC->_dec($x->{value});
1240 # calculate $x = $a ** $base + $b and return $a (e.g. the log() to base
1244 my ($self,$x,$base,@r) = (undef,@_);
1245 # objectify is costly, so avoid it
1246 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1248 ($self,$x,$base,@r) = objectify(1,ref($x),@_);
1251 return $x if $x->modify('blog');
1253 $base = $self->new($base) if defined $base && !ref $base;
1255 # inf, -inf, NaN, <0 => NaN
1257 if $x->{sign} ne '+' || (defined $base && $base->{sign} ne '+');
1259 return $upgrade->blog($upgrade->new($x),$base,@r) if
1262 # fix for bug #24969:
1263 # the default base is e (Euler's number) which is not an integer
1266 require Math::BigFloat;
1267 my $u = Math::BigFloat->blog(Math::BigFloat->new($x))->as_int();
1268 # modify $x in place
1269 $x->{value} = $u->{value};
1270 $x->{sign} = $u->{sign};
1274 my ($rc,$exact) = $CALC->_log_int($x->{value},$base->{value});
1275 return $x->bnan() unless defined $rc; # not possible to take log?
1282 # Calculate n over k (binomial coefficient or "choose" function) as integer.
1284 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1286 # objectify is costly, so avoid it
1287 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1289 ($self,$x,$y,@r) = objectify(2,@_);
1292 return $x if $x->modify('bnok');
1293 return $x->bnan() if $x->{sign} eq 'NaN' || $y->{sign} eq 'NaN';
1294 return $x->binf() if $x->{sign} eq '+inf';
1296 # k > n or k < 0 => 0
1297 my $cmp = $x->bacmp($y);
1298 return $x->bzero() if $cmp < 0 || $y->{sign} =~ /^-/;
1300 return $x->bone(@r) if $cmp == 0;
1302 if ($CALC->can('_nok'))
1304 $x->{value} = $CALC->_nok($x->{value},$y->{value});
1308 # ( 7 ) 7! 7*6*5 * 4*3*2*1 7 * 6 * 5
1309 # ( - ) = --------- = --------------- = ---------
1310 # ( 3 ) 3! (7-3)! 3*2*1 * 4*3*2*1 3 * 2 * 1
1312 # compute n - k + 2 (so we start with 5 in the example above)
1317 my $r = $z->copy(); $z->binc();
1318 my $d = $self->new(2);
1319 while ($z->bacmp($x) <= 0) # f < x ?
1321 $r->bmul($z); $r->bdiv($d);
1322 $z->binc(); $d->binc();
1324 $x->{value} = $r->{value}; $x->{sign} = '+';
1326 else { $x->bone(); }
1333 # Calculate e ** $x (Euler's number to the power of X), truncated to
1335 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1336 return $x if $x->modify('bexp');
1338 # inf, -inf, NaN, <0 => NaN
1339 return $x->bnan() if $x->{sign} eq 'NaN';
1340 return $x->bone() if $x->is_zero();
1341 return $x if $x->{sign} eq '+inf';
1342 return $x->bzero() if $x->{sign} eq '-inf';
1346 # run through Math::BigFloat unless told otherwise
1347 require Math::BigFloat unless defined $upgrade;
1348 local $upgrade = 'Math::BigFloat' unless defined $upgrade;
1349 # calculate result, truncate it to integer
1350 $u = $upgrade->bexp($upgrade->new($x),@r);
1353 if (!defined $upgrade)
1356 # modify $x in place
1357 $x->{value} = $u->{value};
1365 # (BINT or num_str, BINT or num_str) return BINT
1366 # does not modify arguments, but returns new object
1367 # Lowest Common Multiplicator
1369 my $y = shift; my ($x);
1376 $x = $class->new($y);
1381 my $y = shift; $y = $self->new($y) if !ref ($y);
1389 # (BINT or num_str, BINT or num_str) return BINT
1390 # does not modify arguments, but returns new object
1391 # GCD -- Euclids algorithm, variant C (Knuth Vol 3, pg 341 ff)
1394 $y = $class->new($y) if !ref($y);
1396 my $x = $y->copy()->babs(); # keep arguments
1397 return $x->bnan() if $x->{sign} !~ /^[+-]$/; # x NaN?
1401 $y = shift; $y = $self->new($y) if !ref($y);
1402 return $x->bnan() if $y->{sign} !~ /^[+-]$/; # y NaN?
1403 $x->{value} = $CALC->_gcd($x->{value},$y->{value});
1404 last if $CALC->_is_one($x->{value});
1411 # (num_str or BINT) return BINT
1412 # represent ~x as twos-complement number
1413 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1414 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1416 return $x if $x->modify('bnot');
1417 $x->binc()->bneg(); # binc already does round
1420 ##############################################################################
1421 # is_foo test routines
1422 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1426 # return true if arg (BINT or num_str) is zero (array '+', '0')
1427 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1429 return 0 if $x->{sign} !~ /^\+$/; # -, NaN & +-inf aren't
1430 $CALC->_is_zero($x->{value});
1435 # return true if arg (BINT or num_str) is NaN
1436 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1438 $x->{sign} eq $nan ? 1 : 0;
1443 # return true if arg (BINT or num_str) is +-inf
1444 my ($self,$x,$sign) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1448 $sign = '[+-]inf' if $sign eq ''; # +- doesn't matter, only that's inf
1449 $sign = "[$1]inf" if $sign =~ /^([+-])(inf)?$/; # extract '+' or '-'
1450 return $x->{sign} =~ /^$sign$/ ? 1 : 0;
1452 $x->{sign} =~ /^[+-]inf$/ ? 1 : 0; # only +-inf is infinity
1457 # return true if arg (BINT or num_str) is +1, or -1 if sign is given
1458 my ($self,$x,$sign) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1460 $sign = '+' if !defined $sign || $sign ne '-';
1462 return 0 if $x->{sign} ne $sign; # -1 != +1, NaN, +-inf aren't either
1463 $CALC->_is_one($x->{value});
1468 # return true when arg (BINT or num_str) is odd, false for even
1469 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1471 return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
1472 $CALC->_is_odd($x->{value});
1477 # return true when arg (BINT or num_str) is even, false for odd
1478 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1480 return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
1481 $CALC->_is_even($x->{value});
1486 # return true when arg (BINT or num_str) is positive (>= 0)
1487 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1489 return 1 if $x->{sign} eq '+inf'; # +inf is positive
1491 # 0+ is neither positive nor negative
1492 ($x->{sign} eq '+' && !$x->is_zero()) ? 1 : 0;
1497 # return true when arg (BINT or num_str) is negative (< 0)
1498 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1500 $x->{sign} =~ /^-/ ? 1 : 0; # -inf is negative, but NaN is not
1505 # return true when arg (BINT or num_str) is an integer
1506 # always true for BigInt, but different for BigFloats
1507 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1509 $x->{sign} =~ /^[+-]$/ ? 1 : 0; # inf/-inf/NaN aren't
1512 ###############################################################################
1516 # multiply the first number by the second numbers
1517 # (BINT or num_str, BINT or num_str) return BINT
1520 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1521 # objectify is costly, so avoid it
1522 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1524 ($self,$x,$y,@r) = objectify(2,@_);
1527 return $x if $x->modify('bmul');
1529 return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1532 if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
1534 return $x->bnan() if $x->is_zero() || $y->is_zero();
1535 # result will always be +-inf:
1536 # +inf * +/+inf => +inf, -inf * -/-inf => +inf
1537 # +inf * -/-inf => -inf, -inf * +/+inf => -inf
1538 return $x->binf() if ($x->{sign} =~ /^\+/ && $y->{sign} =~ /^\+/);
1539 return $x->binf() if ($x->{sign} =~ /^-/ && $y->{sign} =~ /^-/);
1540 return $x->binf('-');
1543 return $upgrade->bmul($x,$upgrade->new($y),@r)
1544 if defined $upgrade && !$y->isa($self);
1546 $r[3] = $y; # no push here
1548 $x->{sign} = $x->{sign} eq $y->{sign} ? '+' : '-'; # +1 * +1 or -1 * -1 => +
1550 $x->{value} = $CALC->_mul($x->{value},$y->{value}); # do actual math
1551 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # no -0
1558 # multiply two numbers and then add the third to the result
1559 # (BINT or num_str, BINT or num_str, BINT or num_str) return BINT
1562 my ($self,$x,$y,$z,@r) = (ref($_[0]),@_);
1563 # objectify is costly, so avoid it
1564 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1566 ($self,$x,$y,$z,@r) = objectify(3,@_);
1569 return $x if $x->modify('bmuladd');
1571 return $x->bnan() if ($x->{sign} eq $nan) ||
1572 ($y->{sign} eq $nan) ||
1573 ($z->{sign} eq $nan);
1575 # inf handling of x and y
1576 if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
1578 return $x->bnan() if $x->is_zero() || $y->is_zero();
1579 # result will always be +-inf:
1580 # +inf * +/+inf => +inf, -inf * -/-inf => +inf
1581 # +inf * -/-inf => -inf, -inf * +/+inf => -inf
1582 return $x->binf() if ($x->{sign} =~ /^\+/ && $y->{sign} =~ /^\+/);
1583 return $x->binf() if ($x->{sign} =~ /^-/ && $y->{sign} =~ /^-/);
1584 return $x->binf('-');
1586 # inf handling x*y and z
1587 if (($z->{sign} =~ /^[+-]inf$/))
1589 # something +-inf => +-inf
1590 $x->{sign} = $z->{sign}, return $x if $z->{sign} =~ /^[+-]inf$/;
1593 return $upgrade->bmuladd($x,$upgrade->new($y),$upgrade->new($z),@r)
1594 if defined $upgrade && (!$y->isa($self) || !$z->isa($self) || !$x->isa($self));
1596 # TODO: what it $y and $z have A or P set?
1597 $r[3] = $z; # no push here
1599 $x->{sign} = $x->{sign} eq $y->{sign} ? '+' : '-'; # +1 * +1 or -1 * -1 => +
1601 $x->{value} = $CALC->_mul($x->{value},$y->{value}); # do actual math
1602 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # no -0
1604 my ($sx, $sz) = ( $x->{sign}, $z->{sign} ); # get signs
1608 $x->{value} = $CALC->_add($x->{value},$z->{value}); # same sign, abs add
1612 my $a = $CALC->_acmp ($z->{value},$x->{value}); # absolute compare
1615 $x->{value} = $CALC->_sub($z->{value},$x->{value},1); # abs sub w/ swap
1620 # speedup, if equal, set result to 0
1621 $x->{value} = $CALC->_zero();
1626 $x->{value} = $CALC->_sub($x->{value}, $z->{value}); # abs sub
1634 # helper function that handles +-inf cases for bdiv()/bmod() to reuse code
1635 my ($self,$x,$y) = @_;
1637 # NaN if x == NaN or y == NaN or x==y==0
1638 return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan()
1639 if (($x->is_nan() || $y->is_nan()) ||
1640 ($x->is_zero() && $y->is_zero()));
1642 # +-inf / +-inf == NaN, reminder also NaN
1643 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1645 return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan();
1647 # x / +-inf => 0, remainder x (works even if x == 0)
1648 if ($y->{sign} =~ /^[+-]inf$/)
1650 my $t = $x->copy(); # bzero clobbers up $x
1651 return wantarray ? ($x->bzero(),$t) : $x->bzero()
1654 # 5 / 0 => +inf, -6 / 0 => -inf
1655 # +inf / 0 = inf, inf, and -inf / 0 => -inf, -inf
1656 # exception: -8 / 0 has remainder -8, not 8
1657 # exception: -inf / 0 has remainder -inf, not inf
1660 # +-inf / 0 => special case for -inf
1661 return wantarray ? ($x,$x->copy()) : $x if $x->is_inf();
1662 if (!$x->is_zero() && !$x->is_inf())
1664 my $t = $x->copy(); # binf clobbers up $x
1666 ($x->binf($x->{sign}),$t) : $x->binf($x->{sign})
1670 # last case: +-inf / ordinary number
1672 $sign = '-inf' if substr($x->{sign},0,1) ne $y->{sign};
1674 return wantarray ? ($x,$self->bzero()) : $x;
1679 # (dividend: BINT or num_str, divisor: BINT or num_str) return
1680 # (BINT,BINT) (quo,rem) or BINT (only rem)
1683 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1684 # objectify is costly, so avoid it
1685 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1687 ($self,$x,$y,@r) = objectify(2,@_);
1690 return $x if $x->modify('bdiv');
1692 return $self->_div_inf($x,$y)
1693 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero());
1695 return $upgrade->bdiv($upgrade->new($x),$upgrade->new($y),@r)
1696 if defined $upgrade;
1698 $r[3] = $y; # no push!
1700 # calc new sign and in case $y == +/- 1, return $x
1701 my $xsign = $x->{sign}; # keep
1702 $x->{sign} = ($x->{sign} ne $y->{sign} ? '-' : '+');
1706 my $rem = $self->bzero();
1707 ($x->{value},$rem->{value}) = $CALC->_div($x->{value},$y->{value});
1708 $x->{sign} = '+' if $CALC->_is_zero($x->{value});
1709 $rem->{_a} = $x->{_a};
1710 $rem->{_p} = $x->{_p};
1712 if (! $CALC->_is_zero($rem->{value}))
1714 $rem->{sign} = $y->{sign};
1715 $rem = $y->copy()->bsub($rem) if $xsign ne $y->{sign}; # one of them '-'
1719 $rem->{sign} = '+'; # dont leave -0
1725 $x->{value} = $CALC->_div($x->{value},$y->{value});
1726 $x->{sign} = '+' if $CALC->_is_zero($x->{value});
1731 ###############################################################################
1736 # modulus (or remainder)
1737 # (BINT or num_str, BINT or num_str) return BINT
1740 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1741 # objectify is costly, so avoid it
1742 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1744 ($self,$x,$y,@r) = objectify(2,@_);
1747 return $x if $x->modify('bmod');
1748 $r[3] = $y; # no push!
1749 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero())
1751 my ($d,$r) = $self->_div_inf($x,$y);
1752 $x->{sign} = $r->{sign};
1753 $x->{value} = $r->{value};
1754 return $x->round(@r);
1757 # calc new sign and in case $y == +/- 1, return $x
1758 $x->{value} = $CALC->_mod($x->{value},$y->{value});
1759 if (!$CALC->_is_zero($x->{value}))
1761 $x->{value} = $CALC->_sub($y->{value},$x->{value},1) # $y-$x
1762 if ($x->{sign} ne $y->{sign});
1763 $x->{sign} = $y->{sign};
1767 $x->{sign} = '+'; # dont leave -0
1774 # Modular inverse. given a number which is (hopefully) relatively
1775 # prime to the modulus, calculate its inverse using Euclid's
1776 # alogrithm. If the number is not relatively prime to the modulus
1777 # (i.e. their gcd is not one) then NaN is returned.
1780 my ($self,$x,$y,@r) = (undef,@_);
1781 # objectify is costly, so avoid it
1782 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1784 ($self,$x,$y,@r) = objectify(2,@_);
1787 return $x if $x->modify('bmodinv');
1790 if ($y->{sign} ne '+' # -, NaN, +inf, -inf
1791 || $x->is_zero() # or num == 0
1792 || $x->{sign} !~ /^[+-]$/ # or num NaN, inf, -inf
1795 # put least residue into $x if $x was negative, and thus make it positive
1796 $x->bmod($y) if $x->{sign} eq '-';
1799 ($x->{value},$sign) = $CALC->_modinv($x->{value},$y->{value});
1800 return $x->bnan() if !defined $x->{value}; # in case no GCD found
1801 return $x if !defined $sign; # already real result
1802 $x->{sign} = $sign; # flip/flop see below
1803 $x->bmod($y); # calc real result
1809 # takes a very large number to a very large exponent in a given very
1810 # large modulus, quickly, thanks to binary exponentation. Supports
1811 # negative exponents.
1812 my ($self,$num,$exp,$mod,@r) = objectify(3,@_);
1814 return $num if $num->modify('bmodpow');
1816 # check modulus for valid values
1817 return $num->bnan() if ($mod->{sign} ne '+' # NaN, - , -inf, +inf
1818 || $mod->is_zero());
1820 # check exponent for valid values
1821 if ($exp->{sign} =~ /\w/)
1823 # i.e., if it's NaN, +inf, or -inf...
1824 return $num->bnan();
1827 $num->bmodinv ($mod) if ($exp->{sign} eq '-');
1829 # check num for valid values (also NaN if there was no inverse but $exp < 0)
1830 return $num->bnan() if $num->{sign} !~ /^[+-]$/;
1832 # $mod is positive, sign on $exp is ignored, result also positive
1833 $num->{value} = $CALC->_modpow($num->{value},$exp->{value},$mod->{value});
1837 ###############################################################################
1841 # (BINT or num_str, BINT or num_str) return BINT
1842 # compute factorial number from $x, modify $x in place
1843 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1845 return $x if $x->modify('bfac') || $x->{sign} eq '+inf'; # inf => inf
1846 return $x->bnan() if $x->{sign} ne '+'; # NaN, <0 etc => NaN
1848 $x->{value} = $CALC->_fac($x->{value});
1854 # (BINT or num_str, BINT or num_str) return BINT
1855 # compute power of two numbers -- stolen from Knuth Vol 2 pg 233
1856 # modifies first argument
1859 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1860 # objectify is costly, so avoid it
1861 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1863 ($self,$x,$y,@r) = objectify(2,@_);
1866 return $x if $x->modify('bpow');
1868 return $x->bnan() if $x->{sign} eq $nan || $y->{sign} eq $nan;
1871 if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
1873 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1879 if ($x->{sign} =~ /^[+-]inf/)
1882 return $x->bnan() if $y->is_zero();
1883 # -inf ** -1 => 1/inf => 0
1884 return $x->bzero() if $y->is_one('-') && $x->is_negative();
1887 return $x if $x->{sign} eq '+inf';
1889 # -inf ** Y => -inf if Y is odd
1890 return $x if $y->is_odd();
1896 return $x if $x->is_one();
1899 return $x if $x->is_zero() && $y->{sign} =~ /^[+]/;
1902 return $x->binf() if $x->is_zero();
1905 return $x->bnan() if $x->is_one('-') && $y->{sign} =~ /^[-]/;
1908 return $x->bzero() if $x->{sign} eq '-' && $y->{sign} =~ /^[-]/;
1911 return $x->bnan() if $x->{sign} eq '-';
1914 return $x->binf() if $y->{sign} =~ /^[+]/;
1919 return $upgrade->bpow($upgrade->new($x),$y,@r)
1920 if defined $upgrade && (!$y->isa($self) || $y->{sign} eq '-');
1922 $r[3] = $y; # no push!
1924 # cases 0 ** Y, X ** 0, X ** 1, 1 ** Y are handled by Calc or Emu
1927 $new_sign = $y->is_odd() ? '-' : '+' if ($x->{sign} ne '+');
1929 # 0 ** -7 => ( 1 / (0 ** 7)) => 1 / 0 => +inf
1931 if $y->{sign} eq '-' && $x->{sign} eq '+' && $CALC->_is_zero($x->{value});
1932 # 1 ** -y => 1 / (1 ** |y|)
1933 # so do test for negative $y after above's clause
1934 return $x->bnan() if $y->{sign} eq '-' && !$CALC->_is_one($x->{value});
1936 $x->{value} = $CALC->_pow($x->{value},$y->{value});
1937 $x->{sign} = $new_sign;
1938 $x->{sign} = '+' if $CALC->_is_zero($y->{value});
1944 # (BINT or num_str, BINT or num_str) return BINT
1945 # compute x << y, base n, y >= 0
1948 my ($self,$x,$y,$n,@r) = (ref($_[0]),@_);
1949 # objectify is costly, so avoid it
1950 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1952 ($self,$x,$y,$n,@r) = objectify(2,@_);
1955 return $x if $x->modify('blsft');
1956 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1957 return $x->round(@r) if $y->is_zero();
1959 $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
1961 $x->{value} = $CALC->_lsft($x->{value},$y->{value},$n);
1967 # (BINT or num_str, BINT or num_str) return BINT
1968 # compute x >> y, base n, y >= 0
1971 my ($self,$x,$y,$n,@r) = (ref($_[0]),@_);
1972 # objectify is costly, so avoid it
1973 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1975 ($self,$x,$y,$n,@r) = objectify(2,@_);
1978 return $x if $x->modify('brsft');
1979 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1980 return $x->round(@r) if $y->is_zero();
1981 return $x->bzero(@r) if $x->is_zero(); # 0 => 0
1983 $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
1985 # this only works for negative numbers when shifting in base 2
1986 if (($x->{sign} eq '-') && ($n == 2))
1988 return $x->round(@r) if $x->is_one('-'); # -1 => -1
1991 # although this is O(N*N) in calc (as_bin!) it is O(N) in Pari et al
1992 # but perhaps there is a better emulation for two's complement shift...
1993 # if $y != 1, we must simulate it by doing:
1994 # convert to bin, flip all bits, shift, and be done
1995 $x->binc(); # -3 => -2
1996 my $bin = $x->as_bin();
1997 $bin =~ s/^-0b//; # strip '-0b' prefix
1998 $bin =~ tr/10/01/; # flip bits
2000 if ($y >= CORE::length($bin))
2002 $bin = '0'; # shifting to far right creates -1
2003 # 0, because later increment makes
2004 # that 1, attached '-' makes it '-1'
2005 # because -1 >> x == -1 !
2009 $bin =~ s/.{$y}$//; # cut off at the right side
2010 $bin = '1' . $bin; # extend left side by one dummy '1'
2011 $bin =~ tr/10/01/; # flip bits back
2013 my $res = $self->new('0b'.$bin); # add prefix and convert back
2014 $res->binc(); # remember to increment
2015 $x->{value} = $res->{value}; # take over value
2016 return $x->round(@r); # we are done now, magic, isn't?
2018 # x < 0, n == 2, y == 1
2019 $x->bdec(); # n == 2, but $y == 1: this fixes it
2022 $x->{value} = $CALC->_rsft($x->{value},$y->{value},$n);
2028 #(BINT or num_str, BINT or num_str) return BINT
2032 my ($self,$x,$y,@r) = (ref($_[0]),@_);
2033 # objectify is costly, so avoid it
2034 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
2036 ($self,$x,$y,@r) = objectify(2,@_);
2039 return $x if $x->modify('band');
2041 $r[3] = $y; # no push!
2043 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
2045 my $sx = $x->{sign} eq '+' ? 1 : -1;
2046 my $sy = $y->{sign} eq '+' ? 1 : -1;
2048 if ($sx == 1 && $sy == 1)
2050 $x->{value} = $CALC->_and($x->{value},$y->{value});
2051 return $x->round(@r);
2054 if ($CAN{signed_and})
2056 $x->{value} = $CALC->_signed_and($x->{value},$y->{value},$sx,$sy);
2057 return $x->round(@r);
2061 __emu_band($self,$x,$y,$sx,$sy,@r);
2066 #(BINT or num_str, BINT or num_str) return BINT
2070 my ($self,$x,$y,@r) = (ref($_[0]),@_);
2071 # objectify is costly, so avoid it
2072 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
2074 ($self,$x,$y,@r) = objectify(2,@_);
2077 return $x if $x->modify('bior');
2078 $r[3] = $y; # no push!
2080 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
2082 my $sx = $x->{sign} eq '+' ? 1 : -1;
2083 my $sy = $y->{sign} eq '+' ? 1 : -1;
2085 # the sign of X follows the sign of X, e.g. sign of Y irrelevant for bior()
2087 # don't use lib for negative values
2088 if ($sx == 1 && $sy == 1)
2090 $x->{value} = $CALC->_or($x->{value},$y->{value});
2091 return $x->round(@r);
2094 # if lib can do negative values, let it handle this
2095 if ($CAN{signed_or})
2097 $x->{value} = $CALC->_signed_or($x->{value},$y->{value},$sx,$sy);
2098 return $x->round(@r);
2102 __emu_bior($self,$x,$y,$sx,$sy,@r);
2107 #(BINT or num_str, BINT or num_str) return BINT
2111 my ($self,$x,$y,@r) = (ref($_[0]),@_);
2112 # objectify is costly, so avoid it
2113 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
2115 ($self,$x,$y,@r) = objectify(2,@_);
2118 return $x if $x->modify('bxor');
2119 $r[3] = $y; # no push!
2121 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
2123 my $sx = $x->{sign} eq '+' ? 1 : -1;
2124 my $sy = $y->{sign} eq '+' ? 1 : -1;
2126 # don't use lib for negative values
2127 if ($sx == 1 && $sy == 1)
2129 $x->{value} = $CALC->_xor($x->{value},$y->{value});
2130 return $x->round(@r);
2133 # if lib can do negative values, let it handle this
2134 if ($CAN{signed_xor})
2136 $x->{value} = $CALC->_signed_xor($x->{value},$y->{value},$sx,$sy);
2137 return $x->round(@r);
2141 __emu_bxor($self,$x,$y,$sx,$sy,@r);
2146 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
2148 my $e = $CALC->_len($x->{value});
2149 wantarray ? ($e,0) : $e;
2154 # return the nth decimal digit, negative values count backward, 0 is right
2155 my ($self,$x,$n) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2157 $n = $n->numify() if ref($n);
2158 $CALC->_digit($x->{value},$n||0);
2163 # return the amount of trailing zeros in $x (as scalar)
2165 $x = $class->new($x) unless ref $x;
2167 return 0 if $x->{sign} !~ /^[+-]$/; # NaN, inf, -inf etc
2169 $CALC->_zeros($x->{value}); # must handle odd values, 0 etc
2174 # calculate square root of $x
2175 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2177 return $x if $x->modify('bsqrt');
2179 return $x->bnan() if $x->{sign} !~ /^\+/; # -x or -inf or NaN => NaN
2180 return $x if $x->{sign} eq '+inf'; # sqrt(+inf) == inf
2182 return $upgrade->bsqrt($x,@r) if defined $upgrade;
2184 $x->{value} = $CALC->_sqrt($x->{value});
2190 # calculate $y'th root of $x
2193 my ($self,$x,$y,@r) = (ref($_[0]),@_);
2195 $y = $self->new(2) unless defined $y;
2197 # objectify is costly, so avoid it
2198 if ((!ref($x)) || (ref($x) ne ref($y)))
2200 ($self,$x,$y,@r) = objectify(2,$self || $class,@_);
2203 return $x if $x->modify('broot');
2205 # NaN handling: $x ** 1/0, x or y NaN, or y inf/-inf or y == 0
2206 return $x->bnan() if $x->{sign} !~ /^\+/ || $y->is_zero() ||
2207 $y->{sign} !~ /^\+$/;
2209 return $x->round(@r)
2210 if $x->is_zero() || $x->is_one() || $x->is_inf() || $y->is_one();
2212 return $upgrade->new($x)->broot($upgrade->new($y),@r) if defined $upgrade;
2214 $x->{value} = $CALC->_root($x->{value},$y->{value});
2220 # return a copy of the exponent (here always 0, NaN or 1 for $m == 0)
2221 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2223 if ($x->{sign} !~ /^[+-]$/)
2225 my $s = $x->{sign}; $s =~ s/^[+-]//; # NaN, -inf,+inf => NaN or inf
2226 return $self->new($s);
2228 return $self->bone() if $x->is_zero();
2230 # 12300 => 2 trailing zeros => exponent is 2
2231 $self->new( $CALC->_zeros($x->{value}) );
2236 # return the mantissa (compatible to Math::BigFloat, e.g. reduced)
2237 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2239 if ($x->{sign} !~ /^[+-]$/)
2241 # for NaN, +inf, -inf: keep the sign
2242 return $self->new($x->{sign});
2244 my $m = $x->copy(); delete $m->{_p}; delete $m->{_a};
2246 # that's a bit inefficient:
2247 my $zeros = $CALC->_zeros($m->{value});
2248 $m->brsft($zeros,10) if $zeros != 0;
2254 # return a copy of both the exponent and the mantissa
2255 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
2257 ($x->mantissa(),$x->exponent());
2260 ##############################################################################
2261 # rounding functions
2265 # precision: round to the $Nth digit left (+$n) or right (-$n) from the '.'
2266 # $n == 0 || $n == 1 => round to integer
2267 my $x = shift; my $self = ref($x) || $x; $x = $self->new($x) unless ref $x;
2269 my ($scale,$mode) = $x->_scale_p(@_);
2271 return $x if !defined $scale || $x->modify('bfround'); # no-op
2273 # no-op for BigInts if $n <= 0
2274 $x->bround( $x->length()-$scale, $mode) if $scale > 0;
2276 delete $x->{_a}; # delete to save memory
2277 $x->{_p} = $scale; # store new _p
2281 sub _scan_for_nonzero
2283 # internal, used by bround() to scan for non-zeros after a '5'
2284 my ($x,$pad,$xs,$len) = @_;
2286 return 0 if $len == 1; # "5" is trailed by invisible zeros
2287 my $follow = $pad - 1;
2288 return 0 if $follow > $len || $follow < 1;
2290 # use the string form to check whether only '0's follow or not
2291 substr ($xs,-$follow) =~ /[^0]/ ? 1 : 0;
2296 # Exists to make life easier for switch between MBF and MBI (should we
2297 # autoload fxxx() like MBF does for bxxx()?)
2298 my $x = shift; $x = $class->new($x) unless ref $x;
2304 # accuracy: +$n preserve $n digits from left,
2305 # -$n preserve $n digits from right (f.i. for 0.1234 style in MBF)
2307 # and overwrite the rest with 0's, return normalized number
2308 # do not return $x->bnorm(), but $x
2310 my $x = shift; $x = $class->new($x) unless ref $x;
2311 my ($scale,$mode) = $x->_scale_a(@_);
2312 return $x if !defined $scale || $x->modify('bround'); # no-op
2314 if ($x->is_zero() || $scale == 0)
2316 $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale; # 3 > 2
2319 return $x if $x->{sign} !~ /^[+-]$/; # inf, NaN
2321 # we have fewer digits than we want to scale to
2322 my $len = $x->length();
2323 # convert $scale to a scalar in case it is an object (put's a limit on the
2324 # number length, but this would already limited by memory constraints), makes
2326 $scale = $scale->numify() if ref ($scale);
2328 # scale < 0, but > -len (not >=!)
2329 if (($scale < 0 && $scale < -$len-1) || ($scale >= $len))
2331 $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale; # 3 > 2
2335 # count of 0's to pad, from left (+) or right (-): 9 - +6 => 3, or |-6| => 6
2336 my ($pad,$digit_round,$digit_after);
2337 $pad = $len - $scale;
2338 $pad = abs($scale-1) if $scale < 0;
2340 # do not use digit(), it is very costly for binary => decimal
2341 # getting the entire string is also costly, but we need to do it only once
2342 my $xs = $CALC->_str($x->{value});
2345 # pad: 123: 0 => -1, at 1 => -2, at 2 => -3, at 3 => -4
2346 # pad+1: 123: 0 => 0, at 1 => -1, at 2 => -2, at 3 => -3
2347 $digit_round = '0'; $digit_round = substr($xs,$pl,1) if $pad <= $len;
2348 $pl++; $pl ++ if $pad >= $len;
2349 $digit_after = '0'; $digit_after = substr($xs,$pl,1) if $pad > 0;
2351 # in case of 01234 we round down, for 6789 up, and only in case 5 we look
2352 # closer at the remaining digits of the original $x, remember decision
2353 my $round_up = 1; # default round up
2355 ($mode eq 'trunc') || # trunc by round down
2356 ($digit_after =~ /[01234]/) || # round down anyway,
2358 ($digit_after eq '5') && # not 5000...0000
2359 ($x->_scan_for_nonzero($pad,$xs,$len) == 0) &&
2361 ($mode eq 'even') && ($digit_round =~ /[24680]/) ||
2362 ($mode eq 'odd') && ($digit_round =~ /[13579]/) ||
2363 ($mode eq '+inf') && ($x->{sign} eq '-') ||
2364 ($mode eq '-inf') && ($x->{sign} eq '+') ||
2365 ($mode eq 'zero') # round down if zero, sign adjusted below
2367 my $put_back = 0; # not yet modified
2369 if (($pad > 0) && ($pad <= $len))
2371 substr($xs,-$pad,$pad) = '0' x $pad; # replace with '00...'
2372 $put_back = 1; # need to put back
2376 $x->bzero(); # round to '0'
2379 if ($round_up) # what gave test above?
2381 $put_back = 1; # need to put back
2382 $pad = $len, $xs = '0' x $pad if $scale < 0; # tlr: whack 0.51=>1.0
2384 # we modify directly the string variant instead of creating a number and
2385 # adding it, since that is faster (we already have the string)
2386 my $c = 0; $pad ++; # for $pad == $len case
2387 while ($pad <= $len)
2389 $c = substr($xs,-$pad,1) + 1; $c = '0' if $c eq '10';
2390 substr($xs,-$pad,1) = $c; $pad++;
2391 last if $c != 0; # no overflow => early out
2393 $xs = '1'.$xs if $c == 0;
2396 $x->{value} = $CALC->_new($xs) if $put_back == 1; # put back, if needed
2398 $x->{_a} = $scale if $scale >= 0;
2401 $x->{_a} = $len+$scale;
2402 $x->{_a} = 0 if $scale < -$len;
2409 # return integer less or equal then number; no-op since it's already integer
2410 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2417 # return integer greater or equal then number; no-op since it's already int
2418 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2425 # An object might be asked to return itself as bigint on certain overloaded
2426 # operations. This does exactly this, so that sub classes can simple inherit
2427 # it or override with their own integer conversion routine.
2433 # return as hex string, with prefixed 0x
2434 my $x = shift; $x = $class->new($x) if !ref($x);
2436 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2439 $s = $x->{sign} if $x->{sign} eq '-';
2440 $s . $CALC->_as_hex($x->{value});
2445 # return as binary string, with prefixed 0b
2446 my $x = shift; $x = $class->new($x) if !ref($x);
2448 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2450 my $s = ''; $s = $x->{sign} if $x->{sign} eq '-';
2451 return $s . $CALC->_as_bin($x->{value});
2456 # return as octal string, with prefixed 0
2457 my $x = shift; $x = $class->new($x) if !ref($x);
2459 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2461 my $s = ''; $s = $x->{sign} if $x->{sign} eq '-';
2462 return $s . $CALC->_as_oct($x->{value});
2465 ##############################################################################
2466 # private stuff (internal use only)
2470 # check for strings, if yes, return objects instead
2472 # the first argument is number of args objectify() should look at it will
2473 # return $count+1 elements, the first will be a classname. This is because
2474 # overloaded '""' calls bstr($object,undef,undef) and this would result in
2475 # useless objects being created and thrown away. So we cannot simple loop
2476 # over @_. If the given count is 0, all arguments will be used.
2478 # If the second arg is a ref, use it as class.
2479 # If not, try to use it as classname, unless undef, then use $class
2480 # (aka Math::BigInt). The latter shouldn't happen,though.
2483 # $x->badd(1); => ref x, scalar y
2484 # Class->badd(1,2); => classname x (scalar), scalar x, scalar y
2485 # Class->badd( Class->(1),2); => classname x (scalar), ref x, scalar y
2486 # Math::BigInt::badd(1,2); => scalar x, scalar y
2487 # In the last case we check number of arguments to turn it silently into
2488 # $class,1,2. (We can not take '1' as class ;o)
2489 # badd($class,1) is not supported (it should, eventually, try to add undef)
2490 # currently it tries 'Math::BigInt' + 1, which will not work.
2492 # some shortcut for the common cases
2494 return (ref($_[1]),$_[1]) if (@_ == 2) && ($_[0]||0 == 1) && ref($_[1]);
2496 my $count = abs(shift || 0);
2498 my (@a,$k,$d); # resulting array, temp, and downgrade
2501 # okay, got object as first
2506 # nope, got 1,2 (Class->xxx(1) => Class,1 and not supported)
2508 $a[0] = shift if $_[0] =~ /^[A-Z].*::/; # classname as first?
2512 # disable downgrading, because Math::BigFLoat->foo('1.0','2.0') needs floats
2513 if (defined ${"$a[0]::downgrade"})
2515 $d = ${"$a[0]::downgrade"};
2516 ${"$a[0]::downgrade"} = undef;
2519 my $up = ${"$a[0]::upgrade"};
2520 # print STDERR "# Now in objectify, my class is today $a[0], count = $count\n";
2528 $k = $a[0]->new($k);
2530 elsif (!defined $up && ref($k) ne $a[0])
2532 # foreign object, try to convert to integer
2533 $k->can('as_number') ? $k = $k->as_number() : $k = $a[0]->new($k);
2546 $k = $a[0]->new($k);
2548 elsif (!defined $up && ref($k) ne $a[0])
2550 # foreign object, try to convert to integer
2551 $k->can('as_number') ? $k = $k->as_number() : $k = $a[0]->new($k);
2555 push @a,@_; # return other params, too
2559 require Carp; Carp::croak ("$class objectify needs list context");
2561 ${"$a[0]::downgrade"} = $d;
2565 sub _register_callback
2567 my ($class,$callback) = @_;
2569 if (ref($callback) ne 'CODE')
2572 Carp::croak ("$callback is not a coderef");
2574 $CALLBACKS{$class} = $callback;
2581 $IMPORT++; # remember we did import()
2582 my @a; my $l = scalar @_;
2583 my $warn_or_die = 0; # 0 - no warn, 1 - warn, 2 - die
2584 for ( my $i = 0; $i < $l ; $i++ )
2586 if ($_[$i] eq ':constant')
2588 # this causes overlord er load to step in
2590 integer => sub { $self->new(shift) },
2591 binary => sub { $self->new(shift) };
2593 elsif ($_[$i] eq 'upgrade')
2595 # this causes upgrading
2596 $upgrade = $_[$i+1]; # or undef to disable
2599 elsif ($_[$i] =~ /^(lib|try|only)\z/)
2601 # this causes a different low lib to take care...
2602 $CALC = $_[$i+1] || '';
2603 # lib => 1 (warn on fallback), try => 0 (no warn), only => 2 (die on fallback)
2604 $warn_or_die = 1 if $_[$i] eq 'lib';
2605 $warn_or_die = 2 if $_[$i] eq 'only';
2613 # any non :constant stuff is handled by our parent, Exporter
2618 $self->SUPER::import(@a); # need it for subclasses
2619 $self->export_to_level(1,$self,@a); # need it for MBF
2622 # try to load core math lib
2623 my @c = split /\s*,\s*/,$CALC;
2626 $_ =~ tr/a-zA-Z0-9://cd; # limit to sane characters
2628 push @c, \'FastCalc', \'Calc' # if all fail, try these
2629 if $warn_or_die < 2; # but not for "only"
2630 $CALC = ''; # signal error
2633 # fallback libraries are "marked" as \'string', extract string if nec.
2634 my $lib = $l; $lib = $$l if ref($l);
2636 next if ($lib || '') eq '';
2637 $lib = 'Math::BigInt::'.$lib if $lib !~ /^Math::BigInt/i;
2641 # Perl < 5.6.0 dies with "out of memory!" when eval("") and ':constant' is
2642 # used in the same script, or eval("") inside import().
2643 my @parts = split /::/, $lib; # Math::BigInt => Math BigInt
2644 my $file = pop @parts; $file .= '.pm'; # BigInt => BigInt.pm
2646 $file = File::Spec->catfile (@parts, $file);
2647 eval { require "$file"; $lib->import( @c ); }
2651 eval "use $lib qw/@c/;";
2656 # loaded it ok, see if the api_version() is high enough
2657 if ($lib->can('api_version') && $lib->api_version() >= 1.0)
2660 # api_version matches, check if it really provides anything we need
2664 add mul div sub dec inc
2665 acmp len digit is_one is_zero is_even is_odd
2667 zeros new copy check
2668 from_hex from_oct from_bin as_hex as_bin as_oct
2669 rsft lsft xor and or
2670 mod sqrt root fac pow modinv modpow log_int gcd
2673 if (!$lib->can("_$method"))
2675 if (($WARN{$lib}||0) < 2)
2678 Carp::carp ("$lib is missing method '_$method'");
2679 $WARN{$lib} = 1; # still warn about the lib
2688 if ($warn_or_die > 0 && ref($l))
2691 my $msg = "Math::BigInt: couldn't load specified math lib(s), fallback to $lib";
2692 Carp::carp ($msg) if $warn_or_die == 1;
2693 Carp::croak ($msg) if $warn_or_die == 2;
2695 last; # found a usable one, break
2699 if (($WARN{$lib}||0) < 2)
2701 my $ver = eval "\$$lib\::VERSION" || 'unknown';
2703 Carp::carp ("Cannot load outdated $lib v$ver, please upgrade");
2704 $WARN{$lib} = 2; # never warn again
2712 if ($warn_or_die == 2)
2714 Carp::croak ("Couldn't load specified math lib(s) and fallback disallowed");
2718 Carp::croak ("Couldn't load any math lib(s), not even fallback to Calc.pm");
2723 foreach my $class (keys %CALLBACKS)
2725 &{$CALLBACKS{$class}}($CALC);
2728 # Fill $CAN with the results of $CALC->can(...) for emulating lower math lib
2732 for my $method (qw/ signed_and signed_or signed_xor /)
2734 $CAN{$method} = $CALC->can("_$method") ? 1 : 0;
2742 # create a bigint from a hexadecimal string
2743 my ($self, $hs) = @_;
2745 my $rc = $self->__from_hex($hs);
2747 return $self->bnan() unless defined $rc;
2754 # create a bigint from a hexadecimal string
2755 my ($self, $bs) = @_;
2757 my $rc = $self->__from_bin($bs);
2759 return $self->bnan() unless defined $rc;
2766 # create a bigint from a hexadecimal string
2767 my ($self, $os) = @_;
2769 my $x = $self->bzero();
2772 $os =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
2773 $os =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
2775 return $x->bnan() if $os !~ /^[\-\+]?0[0-9]+$/;
2777 my $sign = '+'; $sign = '-' if $os =~ /^-/;
2779 $os =~ s/^[+-]//; # strip sign
2780 $x->{value} = $CALC->_from_oct($os);
2781 $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
2788 # convert a (ref to) big hex string to BigInt, return undef for error
2791 my $x = Math::BigInt->bzero();
2794 $hs =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
2795 $hs =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
2797 return $x->bnan() if $hs !~ /^[\-\+]?0x[0-9A-Fa-f]+$/;
2799 my $sign = '+'; $sign = '-' if $hs =~ /^-/;
2801 $hs =~ s/^[+-]//; # strip sign
2802 $x->{value} = $CALC->_from_hex($hs);
2803 $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
2810 # convert a (ref to) big binary string to BigInt, return undef for error
2813 my $x = Math::BigInt->bzero();
2816 $bs =~ s/([01])_([01])/$1$2/g;
2817 $bs =~ s/([01])_([01])/$1$2/g;
2818 return $x->bnan() if $bs !~ /^[+-]?0b[01]+$/;
2820 my $sign = '+'; $sign = '-' if $bs =~ /^\-/;
2821 $bs =~ s/^[+-]//; # strip sign
2823 $x->{value} = $CALC->_from_bin($bs);
2824 $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
2830 # input: num_str; output: undef for invalid or
2831 # (\$mantissa_sign,\$mantissa_value,\$mantissa_fraction,\$exp_sign,\$exp_value)
2832 # Internal, take apart a string and return the pieces.
2833 # Strip leading/trailing whitespace, leading zeros, underscore and reject
2837 # strip white space at front, also extranous leading zeros
2838 $x =~ s/^\s*([-]?)0*([0-9])/$1$2/g; # will not strip ' .2'
2839 $x =~ s/^\s+//; # but this will
2840 $x =~ s/\s+$//g; # strip white space at end
2842 # shortcut, if nothing to split, return early
2843 if ($x =~ /^[+-]?[0-9]+\z/)
2845 $x =~ s/^([+-])0*([0-9])/$2/; my $sign = $1 || '+';
2846 return (\$sign, \$x, \'', \'', \0);
2849 # invalid starting char?
2850 return if $x !~ /^[+-]?(\.?[0-9]|0b[0-1]|0x[0-9a-fA-F])/;
2852 return __from_hex($x) if $x =~ /^[\-\+]?0x/; # hex string
2853 return __from_bin($x) if $x =~ /^[\-\+]?0b/; # binary string
2855 # strip underscores between digits
2856 $x =~ s/([0-9])_([0-9])/$1$2/g;
2857 $x =~ s/([0-9])_([0-9])/$1$2/g; # do twice for 1_2_3
2859 # some possible inputs:
2860 # 2.1234 # 0.12 # 1 # 1E1 # 2.134E1 # 434E-10 # 1.02009E-2
2861 # .2 # 1_2_3.4_5_6 # 1.4E1_2_3 # 1e3 # +.2 # 0e999
2863 my ($m,$e,$last) = split /[Ee]/,$x;
2864 return if defined $last; # last defined => 1e2E3 or others
2865 $e = '0' if !defined $e || $e eq "";
2867 # sign,value for exponent,mantint,mantfrac
2868 my ($es,$ev,$mis,$miv,$mfv);
2870 if ($e =~ /^([+-]?)0*([0-9]+)$/) # strip leading zeros
2874 return if $m eq '.' || $m eq '';
2875 my ($mi,$mf,$lastf) = split /\./,$m;
2876 return if defined $lastf; # lastf defined => 1.2.3 or others
2877 $mi = '0' if !defined $mi;
2878 $mi .= '0' if $mi =~ /^[\-\+]?$/;
2879 $mf = '0' if !defined $mf || $mf eq '';
2880 if ($mi =~ /^([+-]?)0*([0-9]+)$/) # strip leading zeros
2882 $mis = $1||'+'; $miv = $2;
2883 return unless ($mf =~ /^([0-9]*?)0*$/); # strip trailing zeros
2885 # handle the 0e999 case here
2886 $ev = 0 if $miv eq '0' && $mfv eq '';
2887 return (\$mis,\$miv,\$mfv,\$es,\$ev);
2890 return; # NaN, not a number
2893 ##############################################################################
2894 # internal calculation routines (others are in Math::BigInt::Calc etc)
2898 # (BINT or num_str, BINT or num_str) return BINT
2899 # does modify first argument
2903 return $x->bnan() if ($x->{sign} eq $nan) || ($ty->{sign} eq $nan);
2904 my $method = ref($x) . '::bgcd';
2906 $x * $ty / &$method($x,$ty);
2909 ###############################################################################
2910 # trigonometric functions
2914 # Calculate PI to N digits. Unless upgrading is in effect, returns the
2915 # result truncated to an integer, that is, always returns '3'.
2919 # called like Math::BigInt::bpi(10);
2920 $n = $self; $self = $class;
2922 $self = ref($self) if ref($self);
2924 return $upgrade->new($n) if defined $upgrade;
2930 ###############################################################################
2931 # this method returns 0 if the object can be modified, or 1 if not.
2932 # We use a fast constant sub() here, to avoid costly calls. Subclasses
2933 # may override it with special code (f.i. Math::BigInt::Constant does so)
2935 sub modify () { 0; }
2944 Math::BigInt - Arbitrary size integer/float math package
2950 # or make it faster: install (optional) Math::BigInt::GMP
2951 # and always use (it will fall back to pure Perl if the
2952 # GMP library is not installed):
2954 # will warn if Math::BigInt::GMP cannot be found
2955 use Math::BigInt lib => 'GMP';
2957 # to supress the warning use this:
2958 # use Math::BigInt try => 'GMP';
2960 my $str = '1234567890';
2961 my @values = (64,74,18);
2962 my $n = 1; my $sign = '-';
2965 my $x = Math::BigInt->new($str); # defaults to 0
2966 my $y = $x->copy(); # make a true copy
2967 my $nan = Math::BigInt->bnan(); # create a NotANumber
2968 my $zero = Math::BigInt->bzero(); # create a +0
2969 my $inf = Math::BigInt->binf(); # create a +inf
2970 my $inf = Math::BigInt->binf('-'); # create a -inf
2971 my $one = Math::BigInt->bone(); # create a +1
2972 my $mone = Math::BigInt->bone('-'); # create a -1
2974 my $pi = Math::BigInt->bpi(); # returns '3'
2975 # see Math::BigFloat::bpi()
2977 $h = Math::BigInt->new('0x123'); # from hexadecimal
2978 $b = Math::BigInt->new('0b101'); # from binary
2979 $o = Math::BigInt->from_oct('0101'); # from octal
2981 # Testing (don't modify their arguments)
2982 # (return true if the condition is met, otherwise false)
2984 $x->is_zero(); # if $x is +0
2985 $x->is_nan(); # if $x is NaN
2986 $x->is_one(); # if $x is +1
2987 $x->is_one('-'); # if $x is -1
2988 $x->is_odd(); # if $x is odd
2989 $x->is_even(); # if $x is even
2990 $x->is_pos(); # if $x >= 0
2991 $x->is_neg(); # if $x < 0
2992 $x->is_inf($sign); # if $x is +inf, or -inf (sign is default '+')
2993 $x->is_int(); # if $x is an integer (not a float)
2995 # comparing and digit/sign extraction
2996 $x->bcmp($y); # compare numbers (undef,<0,=0,>0)
2997 $x->bacmp($y); # compare absolutely (undef,<0,=0,>0)
2998 $x->sign(); # return the sign, either +,- or NaN
2999 $x->digit($n); # return the nth digit, counting from right
3000 $x->digit(-$n); # return the nth digit, counting from left
3002 # The following all modify their first argument. If you want to preserve
3003 # $x, use $z = $x->copy()->bXXX($y); See under L<CAVEATS> for why this is
3004 # necessary when mixing $a = $b assignments with non-overloaded math.
3006 $x->bzero(); # set $x to 0
3007 $x->bnan(); # set $x to NaN
3008 $x->bone(); # set $x to +1
3009 $x->bone('-'); # set $x to -1
3010 $x->binf(); # set $x to inf
3011 $x->binf('-'); # set $x to -inf
3013 $x->bneg(); # negation
3014 $x->babs(); # absolute value
3015 $x->bnorm(); # normalize (no-op in BigInt)
3016 $x->bnot(); # two's complement (bit wise not)
3017 $x->binc(); # increment $x by 1
3018 $x->bdec(); # decrement $x by 1
3020 $x->badd($y); # addition (add $y to $x)
3021 $x->bsub($y); # subtraction (subtract $y from $x)
3022 $x->bmul($y); # multiplication (multiply $x by $y)
3023 $x->bdiv($y); # divide, set $x to quotient
3024 # return (quo,rem) or quo if scalar
3026 $x->bmuladd($y,$z); # $x = $x * $y + $z
3028 $x->bmod($y); # modulus (x % y)
3029 $x->bmodpow($exp,$mod); # modular exponentation (($num**$exp) % $mod))
3030 $x->bmodinv($mod); # the inverse of $x in the given modulus $mod
3032 $x->bpow($y); # power of arguments (x ** y)
3033 $x->blsft($y); # left shift in base 2
3034 $x->brsft($y); # right shift in base 2
3035 # returns (quo,rem) or quo if in scalar context
3036 $x->blsft($y,$n); # left shift by $y places in base $n
3037 $x->brsft($y,$n); # right shift by $y places in base $n
3038 # returns (quo,rem) or quo if in scalar context
3040 $x->band($y); # bitwise and
3041 $x->bior($y); # bitwise inclusive or
3042 $x->bxor($y); # bitwise exclusive or
3043 $x->bnot(); # bitwise not (two's complement)
3045 $x->bsqrt(); # calculate square-root
3046 $x->broot($y); # $y'th root of $x (e.g. $y == 3 => cubic root)
3047 $x->bfac(); # factorial of $x (1*2*3*4*..$x)
3049 $x->bnok($y); # x over y (binomial coefficient n over k)
3051 $x->blog(); # logarithm of $x to base e (Euler's number)
3052 $x->blog($base); # logarithm of $x to base $base (f.i. 2)
3053 $x->bexp(); # calculate e ** $x where e is Euler's number
3055 $x->round($A,$P,$mode); # round to accuracy or precision using mode $mode
3056 $x->bround($n); # accuracy: preserve $n digits
3057 $x->bfround($n); # round to $nth digit, no-op for BigInts
3059 # The following do not modify their arguments in BigInt (are no-ops),
3060 # but do so in BigFloat:
3062 $x->bfloor(); # return integer less or equal than $x
3063 $x->bceil(); # return integer greater or equal than $x
3065 # The following do not modify their arguments:
3067 # greatest common divisor (no OO style)
3068 my $gcd = Math::BigInt::bgcd(@values);
3069 # lowest common multiplicator (no OO style)
3070 my $lcm = Math::BigInt::blcm(@values);
3072 $x->length(); # return number of digits in number
3073 ($xl,$f) = $x->length(); # length of number and length of fraction part,
3074 # latter is always 0 digits long for BigInts
3076 $x->exponent(); # return exponent as BigInt
3077 $x->mantissa(); # return (signed) mantissa as BigInt
3078 $x->parts(); # return (mantissa,exponent) as BigInt
3079 $x->copy(); # make a true copy of $x (unlike $y = $x;)
3080 $x->as_int(); # return as BigInt (in BigInt: same as copy())
3081 $x->numify(); # return as scalar (might overflow!)
3083 # conversation to string (do not modify their argument)
3084 $x->bstr(); # normalized string (e.g. '3')
3085 $x->bsstr(); # norm. string in scientific notation (e.g. '3E0')
3086 $x->as_hex(); # as signed hexadecimal string with prefixed 0x
3087 $x->as_bin(); # as signed binary string with prefixed 0b
3088 $x->as_oct(); # as signed octal string with prefixed 0
3091 # precision and accuracy (see section about rounding for more)
3092 $x->precision(); # return P of $x (or global, if P of $x undef)
3093 $x->precision($n); # set P of $x to $n
3094 $x->accuracy(); # return A of $x (or global, if A of $x undef)
3095 $x->accuracy($n); # set A $x to $n
3098 Math::BigInt->precision(); # get/set global P for all BigInt objects
3099 Math::BigInt->accuracy(); # get/set global A for all BigInt objects
3100 Math::BigInt->round_mode(); # get/set global round mode, one of
3101 # 'even', 'odd', '+inf', '-inf', 'zero', 'trunc' or 'common'
3102 Math::BigInt->config(); # return hash containing configuration
3106 All operators (including basic math operations) are overloaded if you
3107 declare your big integers as
3109 $i = new Math::BigInt '123_456_789_123_456_789';
3111 Operations with overloaded operators preserve the arguments which is
3112 exactly what you expect.
3118 Input values to these routines may be any string, that looks like a number
3119 and results in an integer, including hexadecimal and binary numbers.
3121 Scalars holding numbers may also be passed, but note that non-integer numbers
3122 may already have lost precision due to the conversation to float. Quote
3123 your input if you want BigInt to see all the digits:
3125 $x = Math::BigInt->new(12345678890123456789); # bad
3126 $x = Math::BigInt->new('12345678901234567890'); # good
3128 You can include one underscore between any two digits.
3130 This means integer values like 1.01E2 or even 1000E-2 are also accepted.
3131 Non-integer values result in NaN.
3133 Hexadecimal (prefixed with "0x") and binary numbers (prefixed with "0b")
3134 are accepted, too. Please note that octal numbers are not recognized
3135 by new(), so the following will print "123":
3137 perl -MMath::BigInt -le 'print Math::BigInt->new("0123")'
3139 To convert an octal number, use from_oct();
3141 perl -MMath::BigInt -le 'print Math::BigInt->from_oct("0123")'
3143 Currently, Math::BigInt::new() defaults to 0, while Math::BigInt::new('')
3144 results in 'NaN'. This might change in the future, so use always the following
3145 explicit forms to get a zero or NaN:
3147 $zero = Math::BigInt->bzero();
3148 $nan = Math::BigInt->bnan();
3150 C<bnorm()> on a BigInt object is now effectively a no-op, since the numbers
3151 are always stored in normalized form. If passed a string, creates a BigInt
3152 object from the input.
3156 Output values are BigInt objects (normalized), except for the methods which
3157 return a string (see L<SYNOPSIS>).
3159 Some routines (C<is_odd()>, C<is_even()>, C<is_zero()>, C<is_one()>,
3160 C<is_nan()>, etc.) return true or false, while others (C<bcmp()>, C<bacmp()>)
3161 return either undef (if NaN is involved), <0, 0 or >0 and are suited for sort.
3167 Each of the methods below (except config(), accuracy() and precision())
3168 accepts three additional parameters. These arguments C<$A>, C<$P> and C<$R>
3169 are C<accuracy>, C<precision> and C<round_mode>. Please see the section about
3170 L<ACCURACY and PRECISION> for more information.
3176 print Dumper ( Math::BigInt->config() );
3177 print Math::BigInt->config()->{lib},"\n";
3179 Returns a hash containing the configuration, e.g. the version number, lib
3180 loaded etc. The following hash keys are currently filled in with the
3181 appropriate information.
3185 ============================================================
3186 lib Name of the low-level math library
3188 lib_version Version of low-level math library (see 'lib')
3190 class The class name of config() you just called
3192 upgrade To which class math operations might be upgraded
3194 downgrade To which class math operations might be downgraded
3196 precision Global precision
3198 accuracy Global accuracy
3200 round_mode Global round mode
3202 version version number of the class you used
3204 div_scale Fallback accuracy for div
3206 trap_nan If true, traps creation of NaN via croak()
3208 trap_inf If true, traps creation of +inf/-inf via croak()
3211 The following values can be set by passing C<config()> a reference to a hash:
3214 upgrade downgrade precision accuracy round_mode div_scale
3218 $new_cfg = Math::BigInt->config( { trap_inf => 1, precision => 5 } );
3222 $x->accuracy(5); # local for $x
3223 CLASS->accuracy(5); # global for all members of CLASS
3224 # Note: This also applies to new()!
3226 $A = $x->accuracy(); # read out accuracy that affects $x
3227 $A = CLASS->accuracy(); # read out global accuracy
3229 Set or get the global or local accuracy, aka how many significant digits the
3230 results have. If you set a global accuracy, then this also applies to new()!
3232 Warning! The accuracy I<sticks>, e.g. once you created a number under the
3233 influence of C<< CLASS->accuracy($A) >>, all results from math operations with
3234 that number will also be rounded.
3236 In most cases, you should probably round the results explicitly using one of
3237 L<round()>, L<bround()> or L<bfround()> or by passing the desired accuracy
3238 to the math operation as additional parameter:
3240 my $x = Math::BigInt->new(30000);
3241 my $y = Math::BigInt->new(7);
3242 print scalar $x->copy()->bdiv($y, 2); # print 4300
3243 print scalar $x->copy()->bdiv($y)->bround(2); # print 4300
3245 Please see the section about L<ACCURACY AND PRECISION> for further details.
3247 Value must be greater than zero. Pass an undef value to disable it:
3249 $x->accuracy(undef);
3250 Math::BigInt->accuracy(undef);
3252 Returns the current accuracy. For C<$x->accuracy()> it will return either the
3253 local accuracy, or if not defined, the global. This means the return value
3254 represents the accuracy that will be in effect for $x:
3256 $y = Math::BigInt->new(1234567); # unrounded
3257 print Math::BigInt->accuracy(4),"\n"; # set 4, print 4
3258 $x = Math::BigInt->new(123456); # $x will be automatically rounded!
3259 print "$x $y\n"; # '123500 1234567'
3260 print $x->accuracy(),"\n"; # will be 4
3261 print $y->accuracy(),"\n"; # also 4, since global is 4
3262 print Math::BigInt->accuracy(5),"\n"; # set to 5, print 5
3263 print $x->accuracy(),"\n"; # still 4
3264 print $y->accuracy(),"\n"; # 5, since global is 5
3266 Note: Works also for subclasses like Math::BigFloat. Each class has it's own
3267 globals separated from Math::BigInt, but it is possible to subclass
3268 Math::BigInt and make the globals of the subclass aliases to the ones from
3273 $x->precision(-2); # local for $x, round at the second digit right of the dot
3274 $x->precision(2); # ditto, round at the second digit left of the dot
3276 CLASS->precision(5); # Global for all members of CLASS
3277 # This also applies to new()!
3278 CLASS->precision(-5); # ditto
3280 $P = CLASS->precision(); # read out global precision
3281 $P = $x->precision(); # read out precision that affects $x
3283 Note: You probably want to use L<accuracy()> instead. With L<accuracy> you
3284 set the number of digits each result should have, with L<precision> you
3285 set the place where to round!
3287 C<precision()> sets or gets the global or local precision, aka at which digit
3288 before or after the dot to round all results. A set global precision also
3289 applies to all newly created numbers!
3291 In Math::BigInt, passing a negative number precision has no effect since no
3292 numbers have digits after the dot. In L<Math::BigFloat>, it will round all
3293 results to P digits after the dot.
3295 Please see the section about L<ACCURACY AND PRECISION> for further details.
3297 Pass an undef value to disable it:
3299 $x->precision(undef);
3300 Math::BigInt->precision(undef);
3302 Returns the current precision. For C<$x->precision()> it will return either the
3303 local precision of $x, or if not defined, the global. This means the return
3304 value represents the prevision that will be in effect for $x:
3306 $y = Math::BigInt->new(1234567); # unrounded
3307 print Math::BigInt->precision(4),"\n"; # set 4, print 4
3308 $x = Math::BigInt->new(123456); # will be automatically rounded
3309 print $x; # print "120000"!
3311 Note: Works also for subclasses like L<Math::BigFloat>. Each class has its
3312 own globals separated from Math::BigInt, but it is possible to subclass
3313 Math::BigInt and make the globals of the subclass aliases to the ones from
3320 Shifts $x right by $y in base $n. Default is base 2, used are usually 10 and
3321 2, but others work, too.
3323 Right shifting usually amounts to dividing $x by $n ** $y and truncating the
3327 $x = Math::BigInt->new(10);
3328 $x->brsft(1); # same as $x >> 1: 5
3329 $x = Math::BigInt->new(1234);
3330 $x->brsft(2,10); # result 12
3332 There is one exception, and that is base 2 with negative $x:
3335 $x = Math::BigInt->new(-5);
3338 This will print -3, not -2 (as it would if you divide -5 by 2 and truncate the
3343 $x = Math::BigInt->new($str,$A,$P,$R);
3345 Creates a new BigInt object from a scalar or another BigInt object. The
3346 input is accepted as decimal, hex (with leading '0x') or binary (with leading
3349 See L<Input> for more info on accepted input formats.
3353 $x = Math::BigIn->from_oct("0775"); # input is octal
3357 $x = Math::BigIn->from_hex("0xcafe"); # input is hexadecimal
3361 $x = Math::BigIn->from_oct("0x10011"); # input is binary
3365 $x = Math::BigInt->bnan();
3367 Creates a new BigInt object representing NaN (Not A Number).
3368 If used on an object, it will set it to NaN:
3374 $x = Math::BigInt->bzero();
3376 Creates a new BigInt object representing zero.
3377 If used on an object, it will set it to zero:
3383 $x = Math::BigInt->binf($sign);
3385 Creates a new BigInt object representing infinity. The optional argument is
3386 either '-' or '+', indicating whether you want infinity or minus infinity.
3387 If used on an object, it will set it to infinity:
3394 $x = Math::BigInt->binf($sign);
3396 Creates a new BigInt object representing one. The optional argument is
3397 either '-' or '+', indicating whether you want one or minus one.
3398 If used on an object, it will set it to one:
3403 =head2 is_one()/is_zero()/is_nan()/is_inf()
3406 $x->is_zero(); # true if arg is +0
3407 $x->is_nan(); # true if arg is NaN
3408 $x->is_one(); # true if arg is +1
3409 $x->is_one('-'); # true if arg is -1
3410 $x->is_inf(); # true if +inf
3411 $x->is_inf('-'); # true if -inf (sign is default '+')
3413 These methods all test the BigInt for being one specific value and return
3414 true or false depending on the input. These are faster than doing something
3419 =head2 is_pos()/is_neg()/is_positive()/is_negative()
3421 $x->is_pos(); # true if > 0
3422 $x->is_neg(); # true if < 0
3424 The methods return true if the argument is positive or negative, respectively.
3425 C<NaN> is neither positive nor negative, while C<+inf> counts as positive, and
3426 C<-inf> is negative. A C<zero> is neither positive nor negative.
3428 These methods are only testing the sign, and not the value.
3430 C<is_positive()> and C<is_negative()> are aliases to C<is_pos()> and
3431 C<is_neg()>, respectively. C<is_positive()> and C<is_negative()> were
3432 introduced in v1.36, while C<is_pos()> and C<is_neg()> were only introduced
3435 =head2 is_odd()/is_even()/is_int()
3437 $x->is_odd(); # true if odd, false for even
3438 $x->is_even(); # true if even, false for odd
3439 $x->is_int(); # true if $x is an integer
3441 The return true when the argument satisfies the condition. C<NaN>, C<+inf>,
3442 C<-inf> are not integers and are neither odd nor even.
3444 In BigInt, all numbers except C<NaN>, C<+inf> and C<-inf> are integers.
3450 Compares $x with $y and takes the sign into account.
3451 Returns -1, 0, 1 or undef.
3457 Compares $x with $y while ignoring their. Returns -1, 0, 1 or undef.
3463 Return the sign, of $x, meaning either C<+>, C<->, C<-inf>, C<+inf> or NaN.
3465 If you want $x to have a certain sign, use one of the following methods:
3468 $x->babs()->bneg(); # '-'
3470 $x->binf(); # '+inf'
3471 $x->binf('-'); # '-inf'
3475 $x->digit($n); # return the nth digit, counting from right
3477 If C<$n> is negative, returns the digit counting from left.
3483 Negate the number, e.g. change the sign between '+' and '-', or between '+inf'
3484 and '-inf', respectively. Does nothing for NaN or zero.
3490 Set the number to its absolute value, e.g. change the sign from '-' to '+'
3491 and from '-inf' to '+inf', respectively. Does nothing for NaN or positive
3496 $x->bnorm(); # normalize (no-op)
3502 Two's complement (bitwise not). This is equivalent to
3510 $x->binc(); # increment x by 1
3514 $x->bdec(); # decrement x by 1
3518 $x->badd($y); # addition (add $y to $x)
3522 $x->bsub($y); # subtraction (subtract $y from $x)
3526 $x->bmul($y); # multiplication (multiply $x by $y)
3532 Multiply $x by $y, and then add $z to the result,
3534 This method was added in v1.87 of Math::BigInt (June 2007).
3538 $x->bdiv($y); # divide, set $x to quotient
3539 # return (quo,rem) or quo if scalar
3543 $x->bmod($y); # modulus (x % y)
3547 num->bmodinv($mod); # modular inverse
3549 Returns the inverse of C<$num> in the given modulus C<$mod>. 'C<NaN>' is
3550 returned unless C<$num> is relatively prime to C<$mod>, i.e. unless
3551 C<bgcd($num, $mod)==1>.
3555 $num->bmodpow($exp,$mod); # modular exponentation
3556 # ($num**$exp % $mod)
3558 Returns the value of C<$num> taken to the power C<$exp> in the modulus
3559 C<$mod> using binary exponentation. C<bmodpow> is far superior to
3564 because it is much faster - it reduces internal variables into
3565 the modulus whenever possible, so it operates on smaller numbers.
3567 C<bmodpow> also supports negative exponents.
3569 bmodpow($num, -1, $mod)
3571 is exactly equivalent to
3577 $x->bpow($y); # power of arguments (x ** y)
3581 $x->blog($base, $accuracy); # logarithm of x to the base $base
3583 If C<$base> is not defined, Euler's number (e) is used:
3585 print $x->blog(undef, 100); # log(x) to 100 digits
3589 $x->bexp($accuracy); # calculate e ** X
3591 Calculates the expression C<e ** $x> where C<e> is Euler's number.
3593 This method was added in v1.82 of Math::BigInt (April 2007).
3599 $x->bnok($y); # x over y (binomial coefficient n over k)
3601 Calculates the binomial coefficient n over k, also called the "choose"
3602 function. The result is equivalent to:
3608 This method was added in v1.84 of Math::BigInt (April 2007).
3612 print Math::BigInt->bpi(100), "\n"; # 3
3614 Returns PI truncated to an integer, with the argument being ignored. that
3615 is it always returns C<3>.
3617 If upgrading is in effect, returns PI to N digits (including the "3"
3621 use Math::BigInt upgrade => Math::BigFloat;
3622 print Math::BigInt->bpi(3), "\n"; # 3.14
3623 print Math::BigInt->bpi(100), "\n"; # 3.1415....
3625 This method was added in v1.87 of Math::BigInt (June 2007).
3629 $x->blsft($y); # left shift in base 2
3630 $x->blsft($y,$n); # left shift, in base $n (like 10)
3634 $x->brsft($y); # right shift in base 2
3635 $x->brsft($y,$n); # right shift, in base $n (like 10)
3639 $x->band($y); # bitwise and
3643 $x->bior($y); # bitwise inclusive or
3647 $x->bxor($y); # bitwise exclusive or
3651 $x->bnot(); # bitwise not (two's complement)
3655 $x->bsqrt(); # calculate square-root
3659 $x->bfac(); # factorial of $x (1*2*3*4*..$x)
3663 $x->round($A,$P,$round_mode);
3665 Round $x to accuracy C<$A> or precision C<$P> using the round mode
3670 $x->bround($N); # accuracy: preserve $N digits
3674 $x->bfround($N); # round to $Nth digit, no-op for BigInts
3680 Set $x to the integer less or equal than $x. This is a no-op in BigInt, but
3681 does change $x in BigFloat.
3687 Set $x to the integer greater or equal than $x. This is a no-op in BigInt, but
3688 does change $x in BigFloat.
3692 bgcd(@values); # greatest common divisor (no OO style)
3696 blcm(@values); # lowest common multiplicator (no OO style)
3701 ($xl,$fl) = $x->length();
3703 Returns the number of digits in the decimal representation of the number.
3704 In list context, returns the length of the integer and fraction part. For
3705 BigInt's, the length of the fraction part will always be 0.
3711 Return the exponent of $x as BigInt.
3717 Return the signed mantissa of $x as BigInt.
3721 $x->parts(); # return (mantissa,exponent) as BigInt
3725 $x->copy(); # make a true copy of $x (unlike $y = $x;)
3727 =head2 as_int()/as_number()
3731 Returns $x as a BigInt (truncated towards zero). In BigInt this is the same as
3734 C<as_number()> is an alias to this method. C<as_number> was introduced in
3735 v1.22, while C<as_int()> was only introduced in v1.68.
3741 Returns a normalized string representation of C<$x>.
3745 $x->bsstr(); # normalized string in scientific notation
3749 $x->as_hex(); # as signed hexadecimal string with prefixed 0x
3753 $x->as_bin(); # as signed binary string with prefixed 0b
3757 $x->as_oct(); # as signed octal string with prefixed 0
3763 This returns a normal Perl scalar from $x. It is used automatically
3764 whenever a scalar is needed, for instance in array index operations.
3766 This loses precision, to avoid this use L<as_int()> instead.
3770 $x->modify('bpowd');
3772 This method returns 0 if the object can be modified with the given
3773 peration, or 1 if not.
3775 This is used for instance by L<Math::BigInt::Constant>.
3777 =head2 upgrade()/downgrade()
3779 Set/get the class for downgrade/upgrade operations. Thuis is used
3780 for instance by L<bignum>. The defaults are '', thus the following
3781 operation will create a BigInt, not a BigFloat:
3783 my $i = Math::BigInt->new(123);
3784 my $f = Math::BigFloat->new('123.1');
3786 print $i + $f,"\n"; # print 246
3790 Set/get the number of digits for the default precision in divide
3795 Set/get the current round mode.
3797 =head1 ACCURACY and PRECISION
3799 Since version v1.33, Math::BigInt and Math::BigFloat have full support for
3800 accuracy and precision based rounding, both automatically after every
3801 operation, as well as manually.
3803 This section describes the accuracy/precision handling in Math::Big* as it
3804 used to be and as it is now, complete with an explanation of all terms and
3807 Not yet implemented things (but with correct description) are marked with '!',
3808 things that need to be answered are marked with '?'.
3810 In the next paragraph follows a short description of terms used here (because
3811 these may differ from terms used by others people or documentation).
3813 During the rest of this document, the shortcuts A (for accuracy), P (for
3814 precision), F (fallback) and R (rounding mode) will be used.
3818 A fixed number of digits before (positive) or after (negative)
3819 the decimal point. For example, 123.45 has a precision of -2. 0 means an
3820 integer like 123 (or 120). A precision of 2 means two digits to the left
3821 of the decimal point are zero, so 123 with P = 1 becomes 120. Note that
3822 numbers with zeros before the decimal point may have different precisions,
3823 because 1200 can have p = 0, 1 or 2 (depending on what the inital value
3824 was). It could also have p < 0, when the digits after the decimal point
3827 The string output (of floating point numbers) will be padded with zeros:
3829 Initial value P A Result String
3830 ------------------------------------------------------------
3831 1234.01 -3 1000 1000
3834 1234.001 1 1234 1234.0
3836 1234.01 2 1234.01 1234.01
3837 1234.01 5 1234.01 1234.01000
3839 For BigInts, no padding occurs.
3843 Number of significant digits. Leading zeros are not counted. A
3844 number may have an accuracy greater than the non-zero digits
3845 when there are zeros in it or trailing zeros. For example, 123.456 has
3846 A of 6, 10203 has 5, 123.0506 has 7, 123.450000 has 8 and 0.000123 has 3.
3848 The string output (of floating point numbers) will be padded with zeros:
3850 Initial value P A Result String
3851 ------------------------------------------------------------
3853 1234.01 6 1234.01 1234.01
3854 1234.1 8 1234.1 1234.1000
3856 For BigInts, no padding occurs.
3860 When both A and P are undefined, this is used as a fallback accuracy when
3863 =head2 Rounding mode R
3865 When rounding a number, different 'styles' or 'kinds'
3866 of rounding are possible. (Note that random rounding, as in
3867 Math::Round, is not implemented.)
3873 truncation invariably removes all digits following the
3874 rounding place, replacing them with zeros. Thus, 987.65 rounded
3875 to tens (P=1) becomes 980, and rounded to the fourth sigdig
3876 becomes 987.6 (A=4). 123.456 rounded to the second place after the
3877 decimal point (P=-2) becomes 123.46.
3879 All other implemented styles of rounding attempt to round to the
3880 "nearest digit." If the digit D immediately to the right of the
3881 rounding place (skipping the decimal point) is greater than 5, the
3882 number is incremented at the rounding place (possibly causing a
3883 cascade of incrementation): e.g. when rounding to units, 0.9 rounds
3884 to 1, and -19.9 rounds to -20. If D < 5, the number is similarly
3885 truncated at the rounding place: e.g. when rounding to units, 0.4
3886 rounds to 0, and -19.4 rounds to -19.
3888 However the results of other styles of rounding differ if the
3889 digit immediately to the right of the rounding place (skipping the
3890 decimal point) is 5 and if there are no digits, or no digits other
3891 than 0, after that 5. In such cases:
3895 rounds the digit at the rounding place to 0, 2, 4, 6, or 8
3896 if it is not already. E.g., when rounding to the first sigdig, 0.45
3897 becomes 0.4, -0.55 becomes -0.6, but 0.4501 becomes 0.5.
3901 rounds the digit at the rounding place to 1, 3, 5, 7, or 9 if
3902 it is not already. E.g., when rounding to the first sigdig, 0.45
3903 becomes 0.5, -0.55 becomes -0.5, but 0.5501 becomes 0.6.
3907 round to plus infinity, i.e. always round up. E.g., when
3908 rounding to the first sigdig, 0.45 becomes 0.5, -0.55 becomes -0.5,
3909 and 0.4501 also becomes 0.5.
3913 round to minus infinity, i.e. always round down. E.g., when
3914 rounding to the first sigdig, 0.45 becomes 0.4, -0.55 becomes -0.6,
3915 but 0.4501 becomes 0.5.
3919 round to zero, i.e. positive numbers down, negative ones up.
3920 E.g., when rounding to the first sigdig, 0.45 becomes 0.4, -0.55
3921 becomes -0.5, but 0.4501 becomes 0.5.
3925 round up if the digit immediately to the right of the rounding place
3926 is 5 or greater, otherwise round down. E.g., 0.15 becomes 0.2 and
3931 The handling of A & P in MBI/MBF (the old core code shipped with Perl
3932 versions <= 5.7.2) is like this:
3938 * ffround($p) is able to round to $p number of digits after the decimal
3940 * otherwise P is unused
3942 =item Accuracy (significant digits)
3944 * fround($a) rounds to $a significant digits
3945 * only fdiv() and fsqrt() take A as (optional) paramater
3946 + other operations simply create the same number (fneg etc), or more (fmul)
3948 + rounding/truncating is only done when explicitly calling one of fround
3949 or ffround, and never for BigInt (not implemented)
3950 * fsqrt() simply hands its accuracy argument over to fdiv.
3951 * the documentation and the comment in the code indicate two different ways
3952 on how fdiv() determines the maximum number of digits it should calculate,
3953 and the actual code does yet another thing
3955 max($Math::BigFloat::div_scale,length(dividend)+length(divisor))
3957 result has at most max(scale, length(dividend), length(divisor)) digits
3959 scale = max(scale, length(dividend)-1,length(divisor)-1);
3960 scale += length(divisor) - length(dividend);
3961 So for lx = 3, ly = 9, scale = 10, scale will actually be 16 (10+9-3).
3962 Actually, the 'difference' added to the scale is calculated from the
3963 number of "significant digits" in dividend and divisor, which is derived
3964 by looking at the length of the mantissa. Which is wrong, since it includes
3965 the + sign (oops) and actually gets 2 for '+100' and 4 for '+101'. Oops
3966 again. Thus 124/3 with div_scale=1 will get you '41.3' based on the strange
3967 assumption that 124 has 3 significant digits, while 120/7 will get you
3968 '17', not '17.1' since 120 is thought to have 2 significant digits.
3969 The rounding after the division then uses the remainder and $y to determine
3970 wether it must round up or down.
3971 ? I have no idea which is the right way. That's why I used a slightly more
3972 ? simple scheme and tweaked the few failing testcases to match it.
3976 This is how it works now:
3980 =item Setting/Accessing
3982 * You can set the A global via C<< Math::BigInt->accuracy() >> or
3983 C<< Math::BigFloat->accuracy() >> or whatever class you are using.
3984 * You can also set P globally by using C<< Math::SomeClass->precision() >>
3986 * Globals are classwide, and not inherited by subclasses.
3987 * to undefine A, use C<< Math::SomeCLass->accuracy(undef); >>
3988 * to undefine P, use C<< Math::SomeClass->precision(undef); >>
3989 * Setting C<< Math::SomeClass->accuracy() >> clears automatically
3990 C<< Math::SomeClass->precision() >>, and vice versa.
3991 * To be valid, A must be > 0, P can have any value.
3992 * If P is negative, this means round to the P'th place to the right of the
3993 decimal point; positive values mean to the left of the decimal point.
3994 P of 0 means round to integer.
3995 * to find out the current global A, use C<< Math::SomeClass->accuracy() >>
3996 * to find out the current global P, use C<< Math::SomeClass->precision() >>
3997 * use C<< $x->accuracy() >> respective C<< $x->precision() >> for the local
3998 setting of C<< $x >>.
3999 * Please note that C<< $x->accuracy() >> respective C<< $x->precision() >>
4000 return eventually defined global A or P, when C<< $x >>'s A or P is not
4003 =item Creating numbers
4005 * When you create a number, you can give the desired A or P via:
4006 $x = Math::BigInt->new($number,$A,$P);
4007 * Only one of A or P can be defined, otherwise the result is NaN
4008 * If no A or P is give ($x = Math::BigInt->new($number) form), then the
4009 globals (if set) will be used. Thus changing the global defaults later on
4010 will not change the A or P of previously created numbers (i.e., A and P of
4011 $x will be what was in effect when $x was created)
4012 * If given undef for A and P, B<no> rounding will occur, and the globals will
4013 B<not> be used. This is used by subclasses to create numbers without
4014 suffering rounding in the parent. Thus a subclass is able to have its own
4015 globals enforced upon creation of a number by using
4016 C<< $x = Math::BigInt->new($number,undef,undef) >>:
4018 use Math::BigInt::SomeSubclass;
4021 Math::BigInt->accuracy(2);
4022 Math::BigInt::SomeSubClass->accuracy(3);
4023 $x = Math::BigInt::SomeSubClass->new(1234);
4025 $x is now 1230, and not 1200. A subclass might choose to implement
4026 this otherwise, e.g. falling back to the parent's A and P.
4030 * If A or P are enabled/defined, they are used to round the result of each
4031 operation according to the rules below
4032 * Negative P is ignored in Math::BigInt, since BigInts never have digits
4033 after the decimal point
4034 * Math::BigFloat uses Math::BigInt internally, but setting A or P inside
4035 Math::BigInt as globals does not tamper with the parts of a BigFloat.
4036 A flag is used to mark all Math::BigFloat numbers as 'never round'.
4040 * It only makes sense that a number has only one of A or P at a time.
4041 If you set either A or P on one object, or globally, the other one will
4042 be automatically cleared.
4043 * If two objects are involved in an operation, and one of them has A in
4044 effect, and the other P, this results in an error (NaN).
4045 * A takes precedence over P (Hint: A comes before P).
4046 If neither of them is defined, nothing is used, i.e. the result will have
4047 as many digits as it can (with an exception for fdiv/fsqrt) and will not
4049 * There is another setting for fdiv() (and thus for fsqrt()). If neither of
4050 A or P is defined, fdiv() will use a fallback (F) of $div_scale digits.
4051 If either the dividend's or the divisor's mantissa has more digits than
4052 the value of F, the higher value will be used instead of F.
4053 This is to limit the digits (A) of the result (just consider what would
4054 happen with unlimited A and P in the case of 1/3 :-)
4055 * fdiv will calculate (at least) 4 more digits than required (determined by
4056 A, P or F), and, if F is not used, round the result
4057 (this will still fail in the case of a result like 0.12345000000001 with A
4058 or P of 5, but this can not be helped - or can it?)
4059 * Thus you can have the math done by on Math::Big* class in two modi:
4060 + never round (this is the default):
4061 This is done by setting A and P to undef. No math operation
4062 will round the result, with fdiv() and fsqrt() as exceptions to guard
4063 against overflows. You must explicitly call bround(), bfround() or
4064 round() (the latter with parameters).
4065 Note: Once you have rounded a number, the settings will 'stick' on it
4066 and 'infect' all other numbers engaged in math operations with it, since
4067 local settings have the highest precedence. So, to get SaferRound[tm],
4068 use a copy() before rounding like this:
4070 $x = Math::BigFloat->new(12.34);
4071 $y = Math::BigFloat->new(98.76);
4072 $z = $x * $y; # 1218.6984
4073 print $x->copy()->fround(3); # 12.3 (but A is now 3!)
4074 $z = $x * $y; # still 1218.6984, without
4075 # copy would have been 1210!
4077 + round after each op:
4078 After each single operation (except for testing like is_zero()), the
4079 method round() is called and the result is rounded appropriately. By
4080 setting proper values for A and P, you can have all-the-same-A or
4081 all-the-same-P modes. For example, Math::Currency might set A to undef,
4082 and P to -2, globally.
4084 ?Maybe an extra option that forbids local A & P settings would be in order,
4085 ?so that intermediate rounding does not 'poison' further math?
4087 =item Overriding globals
4089 * you will be able to give A, P and R as an argument to all the calculation
4090 routines; the second parameter is A, the third one is P, and the fourth is
4091 R (shift right by one for binary operations like badd). P is used only if
4092 the first parameter (A) is undefined. These three parameters override the
4093 globals in the order detailed as follows, i.e. the first defined value
4095 (local: per object, global: global default, parameter: argument to sub)
4098 + local A (if defined on both of the operands: smaller one is taken)
4099 + local P (if defined on both of the operands: bigger one is taken)
4103 * fsqrt() will hand its arguments to fdiv(), as it used to, only now for two
4104 arguments (A and P) instead of one
4106 =item Local settings
4108 * You can set A or P locally by using C<< $x->accuracy() >> or
4109 C<< $x->precision() >>
4110 and thus force different A and P for different objects/numbers.
4111 * Setting A or P this way immediately rounds $x to the new value.
4112 * C<< $x->accuracy() >> clears C<< $x->precision() >>, and vice versa.
4116 * the rounding routines will use the respective global or local settings.
4117 fround()/bround() is for accuracy rounding, while ffround()/bfround()
4119 * the two rounding functions take as the second parameter one of the
4120 following rounding modes (R):
4121 'even', 'odd', '+inf', '-inf', 'zero', 'trunc', 'common'
4122 * you can set/get the global R by using C<< Math::SomeClass->round_mode() >>
4123 or by setting C<< $Math::SomeClass::round_mode >>
4124 * after each operation, C<< $result->round() >> is called, and the result may
4125 eventually be rounded (that is, if A or P were set either locally,
4126 globally or as parameter to the operation)
4127 * to manually round a number, call C<< $x->round($A,$P,$round_mode); >>
4128 this will round the number by using the appropriate rounding function
4129 and then normalize it.
4130 * rounding modifies the local settings of the number:
4132 $x = Math::BigFloat->new(123.456);
4136 Here 4 takes precedence over 5, so 123.5 is the result and $x->accuracy()
4137 will be 4 from now on.
4139 =item Default values
4148 * The defaults are set up so that the new code gives the same results as
4149 the old code (except in a few cases on fdiv):
4150 + Both A and P are undefined and thus will not be used for rounding
4151 after each operation.
4152 + round() is thus a no-op, unless given extra parameters A and P
4156 =head1 Infinity and Not a Number
4158 While BigInt has extensive handling of inf and NaN, certain quirks remain.
4164 These perl routines currently (as of Perl v.5.8.6) cannot handle passed
4167 te@linux:~> perl -wle 'print 2 ** 3333'
4169 te@linux:~> perl -wle 'print 2 ** 3333 == 2 ** 3333'
4171 te@linux:~> perl -wle 'print oct(2 ** 3333)'
4173 te@linux:~> perl -wle 'print hex(2 ** 3333)'
4174 Illegal hexadecimal digit 'i' ignored at -e line 1.
4177 The same problems occur if you pass them Math::BigInt->binf() objects. Since
4178 overloading these routines is not possible, this cannot be fixed from BigInt.
4180 =item ==, !=, <, >, <=, >= with NaNs
4182 BigInt's bcmp() routine currently returns undef to signal that a NaN was
4183 involved in a comparison. However, the overload code turns that into
4184 either 1 or '' and thus operations like C<< NaN != NaN >> might return
4189 C<< log(-inf) >> is highly weird. Since log(-x)=pi*i+log(x), then
4190 log(-inf)=pi*i+inf. However, since the imaginary part is finite, the real
4191 infinity "overshadows" it, so the number might as well just be infinity.
4192 However, the result is a complex number, and since BigInt/BigFloat can only
4193 have real numbers as results, the result is NaN.
4195 =item exp(), cos(), sin(), atan2()
4197 These all might have problems handling infinity right.
4203 The actual numbers are stored as unsigned big integers (with seperate sign).
4205 You should neither care about nor depend on the internal representation; it
4206 might change without notice. Use B<ONLY> method calls like C<< $x->sign(); >>
4207 instead relying on the internal representation.
4211 Math with the numbers is done (by default) by a module called
4212 C<Math::BigInt::Calc>. This is equivalent to saying:
4214 use Math::BigInt lib => 'Calc';
4216 You can change this by using:
4218 use Math::BigInt lib => 'BitVect';
4220 The following would first try to find Math::BigInt::Foo, then
4221 Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
4223 use Math::BigInt lib => 'Foo,Math::BigInt::Bar';
4225 Since Math::BigInt::GMP is in almost all cases faster than Calc (especially in
4226 math involving really big numbers, where it is B<much> faster), and there is
4227 no penalty if Math::BigInt::GMP is not installed, it is a good idea to always
4230 use Math::BigInt lib => 'GMP';
4232 Different low-level libraries use different formats to store the
4233 numbers. You should B<NOT> depend on the number having a specific format
4236 See the respective math library module documentation for further details.
4240 The sign is either '+', '-', 'NaN', '+inf' or '-inf'.
4242 A sign of 'NaN' is used to represent the result when input arguments are not
4243 numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively
4244 minus infinity. You will get '+inf' when dividing a positive number by 0, and
4245 '-inf' when dividing any negative number by 0.
4247 =head2 mantissa(), exponent() and parts()
4249 C<mantissa()> and C<exponent()> return the said parts of the BigInt such
4252 $m = $x->mantissa();
4253 $e = $x->exponent();
4254 $y = $m * ( 10 ** $e );
4255 print "ok\n" if $x == $y;
4257 C<< ($m,$e) = $x->parts() >> is just a shortcut that gives you both of them
4258 in one go. Both the returned mantissa and exponent have a sign.
4260 Currently, for BigInts C<$e> is always 0, except +inf and -inf, where it is
4261 C<+inf>; and for NaN, where it is C<NaN>; and for C<$x == 0>, where it is C<1>
4262 (to be compatible with Math::BigFloat's internal representation of a zero as
4265 C<$m> is currently just a copy of the original number. The relation between
4266 C<$e> and C<$m> will stay always the same, though their real values might
4273 sub bint { Math::BigInt->new(shift); }
4275 $x = Math::BigInt->bstr("1234") # string "1234"
4276 $x = "$x"; # same as bstr()
4277 $x = Math::BigInt->bneg("1234"); # BigInt "-1234"
4278 $x = Math::BigInt->babs("-12345"); # BigInt "12345"
4279 $x = Math::BigInt->bnorm("-0.00"); # BigInt "0"
4280 $x = bint(1) + bint(2); # BigInt "3"
4281 $x = bint(1) + "2"; # ditto (auto-BigIntify of "2")
4282 $x = bint(1); # BigInt "1"
4283 $x = $x + 5 / 2; # BigInt "3"
4284 $x = $x ** 3; # BigInt "27"
4285 $x *= 2; # BigInt "54"
4286 $x = Math::BigInt->new(0); # BigInt "0"
4288 $x = Math::BigInt->badd(4,5) # BigInt "9"
4289 print $x->bsstr(); # 9e+0
4291 Examples for rounding:
4296 $x = Math::BigFloat->new(123.4567);
4297 $y = Math::BigFloat->new(123.456789);
4298 Math::BigFloat->accuracy(4); # no more A than 4
4300 ok ($x->copy()->fround(),123.4); # even rounding
4301 print $x->copy()->fround(),"\n"; # 123.4
4302 Math::BigFloat->round_mode('odd'); # round to odd
4303 print $x->copy()->fround(),"\n"; # 123.5
4304 Math::BigFloat->accuracy(5); # no more A than 5
4305 Math::BigFloat->round_mode('odd'); # round to odd
4306 print $x->copy()->fround(),"\n"; # 123.46
4307 $y = $x->copy()->fround(4),"\n"; # A = 4: 123.4
4308 print "$y, ",$y->accuracy(),"\n"; # 123.4, 4
4310 Math::BigFloat->accuracy(undef); # A not important now
4311 Math::BigFloat->precision(2); # P important
4312 print $x->copy()->bnorm(),"\n"; # 123.46
4313 print $x->copy()->fround(),"\n"; # 123.46
4315 Examples for converting:
4317 my $x = Math::BigInt->new('0b1'.'01' x 123);
4318 print "bin: ",$x->as_bin()," hex:",$x->as_hex()," dec: ",$x,"\n";
4320 =head1 Autocreating constants
4322 After C<use Math::BigInt ':constant'> all the B<integer> decimal, hexadecimal
4323 and binary constants in the given scope are converted to C<Math::BigInt>.
4324 This conversion happens at compile time.
4328 perl -MMath::BigInt=:constant -e 'print 2**100,"\n"'
4330 prints the integer value of C<2**100>. Note that without conversion of
4331 constants the expression 2**100 will be calculated as perl scalar.
4333 Please note that strings and floating point constants are not affected,
4336 use Math::BigInt qw/:constant/;
4338 $x = 1234567890123456789012345678901234567890
4339 + 123456789123456789;
4340 $y = '1234567890123456789012345678901234567890'
4341 + '123456789123456789';
4343 do not work. You need an explicit Math::BigInt->new() around one of the
4344 operands. You should also quote large constants to protect loss of precision:
4348 $x = Math::BigInt->new('1234567889123456789123456789123456789');
4350 Without the quotes Perl would convert the large number to a floating point
4351 constant at compile time and then hand the result to BigInt, which results in
4352 an truncated result or a NaN.
4354 This also applies to integers that look like floating point constants:
4356 use Math::BigInt ':constant';
4358 print ref(123e2),"\n";
4359 print ref(123.2e2),"\n";
4361 will print nothing but newlines. Use either L<bignum> or L<Math::BigFloat>
4362 to get this to work.
4366 Using the form $x += $y; etc over $x = $x + $y is faster, since a copy of $x
4367 must be made in the second case. For long numbers, the copy can eat up to 20%
4368 of the work (in the case of addition/subtraction, less for
4369 multiplication/division). If $y is very small compared to $x, the form
4370 $x += $y is MUCH faster than $x = $x + $y since making the copy of $x takes
4371 more time then the actual addition.
4373 With a technique called copy-on-write, the cost of copying with overload could
4374 be minimized or even completely avoided. A test implementation of COW did show
4375 performance gains for overloaded math, but introduced a performance loss due
4376 to a constant overhead for all other operations. So Math::BigInt does currently
4379 The rewritten version of this module (vs. v0.01) is slower on certain
4380 operations, like C<new()>, C<bstr()> and C<numify()>. The reason are that it
4381 does now more work and handles much more cases. The time spent in these
4382 operations is usually gained in the other math operations so that code on
4383 the average should get (much) faster. If they don't, please contact the author.
4385 Some operations may be slower for small numbers, but are significantly faster
4386 for big numbers. Other operations are now constant (O(1), like C<bneg()>,
4387 C<babs()> etc), instead of O(N) and thus nearly always take much less time.
4388 These optimizations were done on purpose.
4390 If you find the Calc module to slow, try to install any of the replacement
4391 modules and see if they help you.
4393 =head2 Alternative math libraries
4395 You can use an alternative library to drive Math::BigInt via:
4397 use Math::BigInt lib => 'Module';
4399 See L<MATH LIBRARY> for more information.
4401 For more benchmark results see L<http://bloodgate.com/perl/benchmarks.html>.
4405 =head1 Subclassing Math::BigInt
4407 The basic design of Math::BigInt allows simple subclasses with very little
4408 work, as long as a few simple rules are followed:
4414 The public API must remain consistent, i.e. if a sub-class is overloading
4415 addition, the sub-class must use the same name, in this case badd(). The
4416 reason for this is that Math::BigInt is optimized to call the object methods
4421 The private object hash keys like C<$x->{sign}> may not be changed, but
4422 additional keys can be added, like C<$x->{_custom}>.
4426 Accessor functions are available for all existing object hash keys and should
4427 be used instead of directly accessing the internal hash keys. The reason for
4428 this is that Math::BigInt itself has a pluggable interface which permits it
4429 to support different storage methods.
4433 More complex sub-classes may have to replicate more of the logic internal of
4434 Math::BigInt if they need to change more basic behaviors. A subclass that
4435 needs to merely change the output only needs to overload C<bstr()>.
4437 All other object methods and overloaded functions can be directly inherited
4438 from the parent class.
4440 At the very minimum, any subclass will need to provide its own C<new()> and can
4441 store additional hash keys in the object. There are also some package globals
4442 that must be defined, e.g.:
4446 $precision = -2; # round to 2 decimal places
4447 $round_mode = 'even';
4450 Additionally, you might want to provide the following two globals to allow
4451 auto-upgrading and auto-downgrading to work correctly:
4456 This allows Math::BigInt to correctly retrieve package globals from the
4457 subclass, like C<$SubClass::precision>. See t/Math/BigInt/Subclass.pm or
4458 t/Math/BigFloat/SubClass.pm completely functional subclass examples.
4464 in your subclass to automatically inherit the overloading from the parent. If
4465 you like, you can change part of the overloading, look at Math::String for an
4470 When used like this:
4472 use Math::BigInt upgrade => 'Foo::Bar';
4474 certain operations will 'upgrade' their calculation and thus the result to
4475 the class Foo::Bar. Usually this is used in conjunction with Math::BigFloat:
4477 use Math::BigInt upgrade => 'Math::BigFloat';
4479 As a shortcut, you can use the module C<bignum>:
4483 Also good for oneliners:
4485 perl -Mbignum -le 'print 2 ** 255'
4487 This makes it possible to mix arguments of different classes (as in 2.5 + 2)
4488 as well es preserve accuracy (as in sqrt(3)).
4490 Beware: This feature is not fully implemented yet.
4494 The following methods upgrade themselves unconditionally; that is if upgrade
4495 is in effect, they will always hand up their work:
4509 Beware: This list is not complete.
4511 All other methods upgrade themselves only when one (or all) of their
4512 arguments are of the class mentioned in $upgrade (This might change in later
4513 versions to a more sophisticated scheme):
4517 C<Math::BigInt> exports nothing by default, but can export the following methods:
4526 =item broot() does not work
4528 The broot() function in BigInt may only work for small values. This will be
4529 fixed in a later version.
4531 =item Out of Memory!
4533 Under Perl prior to 5.6.0 having an C<use Math::BigInt ':constant';> and
4534 C<eval()> in your code will crash with "Out of memory". This is probably an
4535 overload/exporter bug. You can workaround by not having C<eval()>
4536 and ':constant' at the same time or upgrade your Perl to a newer version.
4538 =item Fails to load Calc on Perl prior 5.6.0
4540 Since eval(' use ...') can not be used in conjunction with ':constant', BigInt
4541 will fall back to eval { require ... } when loading the math lib on Perls
4542 prior to 5.6.0. This simple replaces '::' with '/' and thus might fail on
4543 filesystems using a different seperator.
4549 Some things might not work as you expect them. Below is documented what is
4550 known to be troublesome:
4554 =item bstr(), bsstr() and 'cmp'
4556 Both C<bstr()> and C<bsstr()> as well as automated stringify via overload now
4557 drop the leading '+'. The old code would return '+3', the new returns '3'.
4558 This is to be consistent with Perl and to make C<cmp> (especially with
4559 overloading) to work as you expect. It also solves problems with C<Test.pm>,
4560 because its C<ok()> uses 'eq' internally.
4562 Mark Biggar said, when asked about to drop the '+' altogether, or make only
4565 I agree (with the first alternative), don't add the '+' on positive
4566 numbers. It's not as important anymore with the new internal
4567 form for numbers. It made doing things like abs and neg easier,
4568 but those have to be done differently now anyway.
4570 So, the following examples will now work all as expected:
4573 BEGIN { plan tests => 1 }
4576 my $x = new Math::BigInt 3*3;
4577 my $y = new Math::BigInt 3*3;
4580 print "$x eq 9" if $x eq $y;
4581 print "$x eq 9" if $x eq '9';
4582 print "$x eq 9" if $x eq 3*3;
4584 Additionally, the following still works:
4586 print "$x == 9" if $x == $y;
4587 print "$x == 9" if $x == 9;
4588 print "$x == 9" if $x == 3*3;
4590 There is now a C<bsstr()> method to get the string in scientific notation aka
4591 C<1e+2> instead of C<100>. Be advised that overloaded 'eq' always uses bstr()
4592 for comparison, but Perl will represent some numbers as 100 and others
4593 as 1e+308. If in doubt, convert both arguments to Math::BigInt before
4594 comparing them as strings:
4597 BEGIN { plan tests => 3 }
4600 $x = Math::BigInt->new('1e56'); $y = 1e56;
4601 ok ($x,$y); # will fail
4602 ok ($x->bsstr(),$y); # okay
4603 $y = Math::BigInt->new($y);
4606 Alternatively, simple use C<< <=> >> for comparisons, this will get it
4607 always right. There is not yet a way to get a number automatically represented
4608 as a string that matches exactly the way Perl represents it.
4610 See also the section about L<Infinity and Not a Number> for problems in
4615 C<int()> will return (at least for Perl v5.7.1 and up) another BigInt, not a
4618 $x = Math::BigInt->new(123);
4619 $y = int($x); # BigInt 123
4620 $x = Math::BigFloat->new(123.45);
4621 $y = int($x); # BigInt 123
4623 In all Perl versions you can use C<as_number()> or C<as_int> for the same
4626 $x = Math::BigFloat->new(123.45);
4627 $y = $x->as_number(); # BigInt 123
4628 $y = $x->as_int(); # ditto
4630 This also works for other subclasses, like Math::String.
4632 If you want a real Perl scalar, use C<numify()>:
4634 $y = $x->numify(); # 123 as scalar
4636 This is seldom necessary, though, because this is done automatically, like
4637 when you access an array:
4639 $z = $array[$x]; # does work automatically
4643 The following will probably not do what you expect:
4645 $c = Math::BigInt->new(123);
4646 print $c->length(),"\n"; # prints 30
4648 It prints both the number of digits in the number and in the fraction part
4649 since print calls C<length()> in list context. Use something like:
4651 print scalar $c->length(),"\n"; # prints 3
4655 The following will probably not do what you expect:
4657 print $c->bdiv(10000),"\n";
4659 It prints both quotient and remainder since print calls C<bdiv()> in list
4660 context. Also, C<bdiv()> will modify $c, so be careful. You probably want
4663 print $c / 10000,"\n";
4664 print scalar $c->bdiv(10000),"\n"; # or if you want to modify $c
4668 The quotient is always the greatest integer less than or equal to the
4669 real-valued quotient of the two operands, and the remainder (when it is
4670 nonzero) always has the same sign as the second operand; so, for
4680 As a consequence, the behavior of the operator % agrees with the
4681 behavior of Perl's built-in % operator (as documented in the perlop
4682 manpage), and the equation
4684 $x == ($x / $y) * $y + ($x % $y)
4686 holds true for any $x and $y, which justifies calling the two return
4687 values of bdiv() the quotient and remainder. The only exception to this rule
4688 are when $y == 0 and $x is negative, then the remainder will also be
4689 negative. See below under "infinity handling" for the reasoning behind this.
4691 Perl's 'use integer;' changes the behaviour of % and / for scalars, but will
4692 not change BigInt's way to do things. This is because under 'use integer' Perl
4693 will do what the underlying C thinks is right and this is different for each
4694 system. If you need BigInt's behaving exactly like Perl's 'use integer', bug
4695 the author to implement it ;)
4697 =item infinity handling
4699 Here are some examples that explain the reasons why certain results occur while
4702 The following table shows the result of the division and the remainder, so that
4703 the equation above holds true. Some "ordinary" cases are strewn in to show more
4704 clearly the reasoning:
4706 A / B = C, R so that C * B + R = A
4707 =========================================================
4708 5 / 8 = 0, 5 0 * 8 + 5 = 5
4709 0 / 8 = 0, 0 0 * 8 + 0 = 0
4710 0 / inf = 0, 0 0 * inf + 0 = 0
4711 0 /-inf = 0, 0 0 * -inf + 0 = 0
4712 5 / inf = 0, 5 0 * inf + 5 = 5
4713 5 /-inf = 0, 5 0 * -inf + 5 = 5
4714 -5/ inf = 0, -5 0 * inf + -5 = -5
4715 -5/-inf = 0, -5 0 * -inf + -5 = -5
4716 inf/ 5 = inf, 0 inf * 5 + 0 = inf
4717 -inf/ 5 = -inf, 0 -inf * 5 + 0 = -inf
4718 inf/ -5 = -inf, 0 -inf * -5 + 0 = inf
4719 -inf/ -5 = inf, 0 inf * -5 + 0 = -inf
4720 5/ 5 = 1, 0 1 * 5 + 0 = 5
4721 -5/ -5 = 1, 0 1 * -5 + 0 = -5
4722 inf/ inf = 1, 0 1 * inf + 0 = inf
4723 -inf/-inf = 1, 0 1 * -inf + 0 = -inf
4724 inf/-inf = -1, 0 -1 * -inf + 0 = inf
4725 -inf/ inf = -1, 0 1 * -inf + 0 = -inf
4726 8/ 0 = inf, 8 inf * 0 + 8 = 8
4727 inf/ 0 = inf, inf inf * 0 + inf = inf
4730 These cases below violate the "remainder has the sign of the second of the two
4731 arguments", since they wouldn't match up otherwise.
4733 A / B = C, R so that C * B + R = A
4734 ========================================================
4735 -inf/ 0 = -inf, -inf -inf * 0 + inf = -inf
4736 -8/ 0 = -inf, -8 -inf * 0 + 8 = -8
4738 =item Modifying and =
4742 $x = Math::BigFloat->new(5);
4745 It will not do what you think, e.g. making a copy of $x. Instead it just makes
4746 a second reference to the B<same> object and stores it in $y. Thus anything
4747 that modifies $x (except overloaded operators) will modify $y, and vice versa.
4748 Or in other words, C<=> is only safe if you modify your BigInts only via
4749 overloaded math. As soon as you use a method call it breaks:
4752 print "$x, $y\n"; # prints '10, 10'
4754 If you want a true copy of $x, use:
4758 You can also chain the calls like this, this will make first a copy and then
4761 $y = $x->copy()->bmul(2);
4763 See also the documentation for overload.pm regarding C<=>.
4767 C<bpow()> (and the rounding functions) now modifies the first argument and
4768 returns it, unlike the old code which left it alone and only returned the
4769 result. This is to be consistent with C<badd()> etc. The first three will
4770 modify $x, the last one won't:
4772 print bpow($x,$i),"\n"; # modify $x
4773 print $x->bpow($i),"\n"; # ditto
4774 print $x **= $i,"\n"; # the same
4775 print $x ** $i,"\n"; # leave $x alone
4777 The form C<$x **= $y> is faster than C<$x = $x ** $y;>, though.
4779 =item Overloading -$x
4789 since overload calls C<sub($x,0,1);> instead of C<neg($x)>. The first variant
4790 needs to preserve $x since it does not know that it later will get overwritten.
4791 This makes a copy of $x and takes O(N), but $x->bneg() is O(1).
4793 =item Mixing different object types
4795 In Perl you will get a floating point value if you do one of the following:
4801 With overloaded math, only the first two variants will result in a BigFloat:
4806 $mbf = Math::BigFloat->new(5);
4807 $mbi2 = Math::BigInteger->new(5);
4808 $mbi = Math::BigInteger->new(2);
4810 # what actually gets called:
4811 $float = $mbf + $mbi; # $mbf->badd()
4812 $float = $mbf / $mbi; # $mbf->bdiv()
4813 $integer = $mbi + $mbf; # $mbi->badd()
4814 $integer = $mbi2 / $mbi; # $mbi2->bdiv()
4815 $integer = $mbi2 / $mbf; # $mbi2->bdiv()
4817 This is because math with overloaded operators follows the first (dominating)
4818 operand, and the operation of that is called and returns thus the result. So,
4819 Math::BigInt::bdiv() will always return a Math::BigInt, regardless whether
4820 the result should be a Math::BigFloat or the second operant is one.
4822 To get a Math::BigFloat you either need to call the operation manually,
4823 make sure the operands are already of the proper type or casted to that type
4824 via Math::BigFloat->new():
4826 $float = Math::BigFloat->new($mbi2) / $mbi; # = 2.5
4828 Beware of simple "casting" the entire expression, this would only convert
4829 the already computed result:
4831 $float = Math::BigFloat->new($mbi2 / $mbi); # = 2.0 thus wrong!
4833 Beware also of the order of more complicated expressions like:
4835 $integer = ($mbi2 + $mbi) / $mbf; # int / float => int
4836 $integer = $mbi2 / Math::BigFloat->new($mbi); # ditto
4838 If in doubt, break the expression into simpler terms, or cast all operands
4839 to the desired resulting type.
4841 Scalar values are a bit different, since:
4846 will both result in the proper type due to the way the overloaded math works.
4848 This section also applies to other overloaded math packages, like Math::String.
4850 One solution to you problem might be autoupgrading|upgrading. See the
4851 pragmas L<bignum>, L<bigint> and L<bigrat> for an easy way to do this.
4855 C<bsqrt()> works only good if the result is a big integer, e.g. the square
4856 root of 144 is 12, but from 12 the square root is 3, regardless of rounding
4857 mode. The reason is that the result is always truncated to an integer.
4859 If you want a better approximation of the square root, then use:
4861 $x = Math::BigFloat->new(12);
4862 Math::BigFloat->precision(0);
4863 Math::BigFloat->round_mode('even');
4864 print $x->copy->bsqrt(),"\n"; # 4
4866 Math::BigFloat->precision(2);
4867 print $x->bsqrt(),"\n"; # 3.46
4868 print $x->bsqrt(3),"\n"; # 3.464
4872 For negative numbers in base see also L<brsft|brsft>.
4878 This program is free software; you may redistribute it and/or modify it under
4879 the same terms as Perl itself.
4883 L<Math::BigFloat>, L<Math::BigRat> and L<Math::Big> as well as
4884 L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>.
4886 The pragmas L<bignum>, L<bigint> and L<bigrat> also might be of interest
4887 because they solve the autoupgrading/downgrading issue, at least partly.
4890 L<http://search.cpan.org/search?mode=module&query=Math%3A%3ABigInt> contains
4891 more documentation including a full version history, testcases, empty
4892 subclass files and benchmarks.
4896 Original code by Mark Biggar, overloaded interface by Ilya Zakharevich.
4897 Completely rewritten by Tels http://bloodgate.com in late 2000, 2001 - 2006
4898 and still at it in 2007.
4900 Many people contributed in one or more ways to the final beast, see the file
4901 CREDITS for an (incomplete) list. If you miss your name, please drop me a