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 $class = "Math::BigInt";
23 @ISA = qw( Exporter );
24 @EXPORT_OK = qw( objectify bgcd blcm);
25 # _trap_inf and _trap_nan are internal and should never be accessed from the
27 use vars qw/$round_mode $accuracy $precision $div_scale $rnd_mode
28 $upgrade $downgrade $_trap_nan $_trap_inf/;
31 # Inside overload, the first arg is always an object. If the original code had
32 # it reversed (like $x = 2 * $y), then the third paramater is true.
33 # In some cases (like add, $x = $x + 2 is the same as $x = 2 + $x) this makes
34 # no difference, but in some cases it does.
36 # For overloaded ops with only one argument we simple use $_[0]->copy() to
37 # preserve the argument.
39 # Thus inheritance of overload operators becomes possible and transparent for
40 # our subclasses without the need to repeat the entire overload section there.
43 '=' => sub { $_[0]->copy(); },
45 # some shortcuts for speed (assumes that reversed order of arguments is routed
46 # to normal '+' and we thus can always modify first arg. If this is changed,
47 # this breaks and must be adjusted.)
48 '+=' => sub { $_[0]->badd($_[1]); },
49 '-=' => sub { $_[0]->bsub($_[1]); },
50 '*=' => sub { $_[0]->bmul($_[1]); },
51 '/=' => sub { scalar $_[0]->bdiv($_[1]); },
52 '%=' => sub { $_[0]->bmod($_[1]); },
53 '^=' => sub { $_[0]->bxor($_[1]); },
54 '&=' => sub { $_[0]->band($_[1]); },
55 '|=' => sub { $_[0]->bior($_[1]); },
56 '**=' => sub { $_[0]->bpow($_[1]); },
58 '<<=' => sub { $_[0]->blsft($_[1]); },
59 '>>=' => sub { $_[0]->brsft($_[1]); },
61 # not supported by Perl yet
62 '..' => \&_pointpoint,
64 '<=>' => sub { $_[2] ?
65 ref($_[0])->bcmp($_[1],$_[0]) :
69 "$_[1]" cmp $_[0]->bstr() :
70 $_[0]->bstr() cmp "$_[1]" },
72 # make cos()/sin()/exp() "work" with BigInt's or subclasses
73 'cos' => sub { cos($_[0]->numify()) },
74 'sin' => sub { sin($_[0]->numify()) },
75 'exp' => sub { exp($_[0]->numify()) },
76 'atan2' => sub { atan2($_[0]->numify(),$_[1]) },
78 'log' => sub { $_[0]->copy()->blog($_[1]); },
79 'int' => sub { $_[0]->copy(); },
80 'neg' => sub { $_[0]->copy()->bneg(); },
81 'abs' => sub { $_[0]->copy()->babs(); },
82 'sqrt' => sub { $_[0]->copy()->bsqrt(); },
83 '~' => sub { $_[0]->copy()->bnot(); },
85 # for subtract it is a bit tricky to keep b: b-a => -a+b
86 '-' => sub { my $c = $_[0]->copy; $_[2] ?
87 $c->bneg()->badd($_[1]) :
89 '+' => sub { $_[0]->copy()->badd($_[1]); },
90 '*' => sub { $_[0]->copy()->bmul($_[1]); },
93 $_[2] ? ref($_[0])->new($_[1])->bdiv($_[0]) : $_[0]->copy->bdiv($_[1]);
96 $_[2] ? ref($_[0])->new($_[1])->bmod($_[0]) : $_[0]->copy->bmod($_[1]);
99 $_[2] ? ref($_[0])->new($_[1])->bpow($_[0]) : $_[0]->copy->bpow($_[1]);
102 $_[2] ? ref($_[0])->new($_[1])->blsft($_[0]) : $_[0]->copy->blsft($_[1]);
105 $_[2] ? ref($_[0])->new($_[1])->brsft($_[0]) : $_[0]->copy->brsft($_[1]);
108 $_[2] ? ref($_[0])->new($_[1])->band($_[0]) : $_[0]->copy->band($_[1]);
111 $_[2] ? ref($_[0])->new($_[1])->bior($_[0]) : $_[0]->copy->bior($_[1]);
114 $_[2] ? ref($_[0])->new($_[1])->bxor($_[0]) : $_[0]->copy->bxor($_[1]);
117 # can modify arg of ++ and --, so avoid a copy() for speed, but don't
118 # use $_[0]->bone(), it would modify $_[0] to be 1!
119 '++' => sub { $_[0]->binc() },
120 '--' => sub { $_[0]->bdec() },
122 # if overloaded, O(1) instead of O(N) and twice as fast for small numbers
124 # this kludge is needed for perl prior 5.6.0 since returning 0 here fails :-/
125 # v5.6.1 dumps on this: return !$_[0]->is_zero() || undef; :-(
127 $t = 1 if !$_[0]->is_zero();
131 # the original qw() does not work with the TIESCALAR below, why?
132 # Order of arguments unsignificant
133 '""' => sub { $_[0]->bstr(); },
134 '0+' => sub { $_[0]->numify(); }
137 ##############################################################################
138 # global constants, flags and accessory
140 # these are public, but their usage is not recommended, use the accessor
143 $round_mode = 'even'; # one of 'even', 'odd', '+inf', '-inf', 'zero' or 'trunc'
148 $upgrade = undef; # default is no upgrade
149 $downgrade = undef; # default is no downgrade
151 # these are internally, and not to be used from the outside
153 sub MB_NEVER_ROUND () { 0x0001; }
155 $_trap_nan = 0; # are NaNs ok? set w/ config()
156 $_trap_inf = 0; # are infs ok? set w/ config()
157 my $nan = 'NaN'; # constants for easier life
159 my $CALC = 'Math::BigInt::Calc'; # module to do the low level math
161 my $IMPORT = 0; # was import() called yet?
162 # used to make require work
163 my %WARN; # warn only once for low-level libs
164 my %CAN; # cache for $CALC->can(...)
165 my $EMU_LIB = 'Math/BigInt/CalcEmu.pm'; # emulate low-level math
167 ##############################################################################
168 # the old code had $rnd_mode, so we need to support it, too
171 sub TIESCALAR { my ($class) = @_; bless \$round_mode, $class; }
172 sub FETCH { return $round_mode; }
173 sub STORE { $rnd_mode = $_[0]->round_mode($_[1]); }
177 # tie to enable $rnd_mode to work transparently
178 tie $rnd_mode, 'Math::BigInt';
180 # set up some handy alias names
181 *as_int = \&as_number;
182 *is_pos = \&is_positive;
183 *is_neg = \&is_negative;
186 ##############################################################################
191 # make Class->round_mode() work
193 my $class = ref($self) || $self || __PACKAGE__;
197 if ($m !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
199 require Carp; Carp::croak ("Unknown round mode '$m'");
201 return ${"${class}::round_mode"} = $m;
203 ${"${class}::round_mode"};
209 # make Class->upgrade() work
211 my $class = ref($self) || $self || __PACKAGE__;
212 # need to set new value?
216 return ${"${class}::upgrade"} = $u;
218 ${"${class}::upgrade"};
224 # make Class->downgrade() work
226 my $class = ref($self) || $self || __PACKAGE__;
227 # need to set new value?
231 return ${"${class}::downgrade"} = $u;
233 ${"${class}::downgrade"};
239 # make Class->div_scale() work
241 my $class = ref($self) || $self || __PACKAGE__;
246 require Carp; Carp::croak ('div_scale must be greater than zero');
248 ${"${class}::div_scale"} = shift;
250 ${"${class}::div_scale"};
255 # $x->accuracy($a); ref($x) $a
256 # $x->accuracy(); ref($x)
257 # Class->accuracy(); class
258 # Class->accuracy($a); class $a
261 my $class = ref($x) || $x || __PACKAGE__;
264 # need to set new value?
268 # convert objects to scalars to avoid deep recursion. If object doesn't
269 # have numify(), then hopefully it will have overloading for int() and
270 # boolean test without wandering into a deep recursion path...
271 $a = $a->numify() if ref($a) && $a->can('numify');
275 # also croak on non-numerical
279 Carp::croak ('Argument to accuracy must be greater than zero');
283 require Carp; Carp::croak ('Argument to accuracy must be an integer');
288 # $object->accuracy() or fallback to global
289 $x->bround($a) if $a; # not for undef, 0
290 $x->{_a} = $a; # set/overwrite, even if not rounded
291 delete $x->{_p}; # clear P
292 $a = ${"${class}::accuracy"} unless defined $a; # proper return value
296 ${"${class}::accuracy"} = $a; # set global A
297 ${"${class}::precision"} = undef; # clear global P
299 return $a; # shortcut
303 # $object->accuracy() or fallback to global
304 $r = $x->{_a} if ref($x);
305 # but don't return global undef, when $x's accuracy is 0!
306 $r = ${"${class}::accuracy"} if !defined $r;
312 # $x->precision($p); ref($x) $p
313 # $x->precision(); ref($x)
314 # Class->precision(); class
315 # Class->precision($p); class $p
318 my $class = ref($x) || $x || __PACKAGE__;
324 # convert objects to scalars to avoid deep recursion. If object doesn't
325 # have numify(), then hopefully it will have overloading for int() and
326 # boolean test without wandering into a deep recursion path...
327 $p = $p->numify() if ref($p) && $p->can('numify');
328 if ((defined $p) && (int($p) != $p))
330 require Carp; Carp::croak ('Argument to precision must be an integer');
334 # $object->precision() or fallback to global
335 $x->bfround($p) if $p; # not for undef, 0
336 $x->{_p} = $p; # set/overwrite, even if not rounded
337 delete $x->{_a}; # clear A
338 $p = ${"${class}::precision"} unless defined $p; # proper return value
342 ${"${class}::precision"} = $p; # set global P
343 ${"${class}::accuracy"} = undef; # clear global A
345 return $p; # shortcut
349 # $object->precision() or fallback to global
350 $r = $x->{_p} if ref($x);
351 # but don't return global undef, when $x's precision is 0!
352 $r = ${"${class}::precision"} if !defined $r;
358 # return (or set) configuration data as hash ref
359 my $class = shift || 'Math::BigInt';
364 # try to set given options as arguments from hash
367 if (ref($args) ne 'HASH')
371 # these values can be "set"
375 upgrade downgrade precision accuracy round_mode div_scale/
378 $set_args->{$key} = $args->{$key} if exists $args->{$key};
379 delete $args->{$key};
384 Carp::croak ("Illegal key(s) '",
385 join("','",keys %$args),"' passed to $class\->config()");
387 foreach my $key (keys %$set_args)
389 if ($key =~ /^trap_(inf|nan)\z/)
391 ${"${class}::_trap_$1"} = ($set_args->{"trap_$1"} ? 1 : 0);
394 # use a call instead of just setting the $variable to check argument
395 $class->$key($set_args->{$key});
399 # now return actual configuration
403 lib_version => ${"${CALC}::VERSION"},
405 trap_nan => ${"${class}::_trap_nan"},
406 trap_inf => ${"${class}::_trap_inf"},
407 version => ${"${class}::VERSION"},
410 upgrade downgrade precision accuracy round_mode div_scale
413 $cfg->{$key} = ${"${class}::$key"};
420 # select accuracy parameter based on precedence,
421 # used by bround() and bfround(), may return undef for scale (means no op)
422 my ($x,$s,$m,$scale,$mode) = @_;
423 $scale = $x->{_a} if !defined $scale;
424 $scale = $s if (!defined $scale);
425 $mode = $m if !defined $mode;
426 return ($scale,$mode);
431 # select precision parameter based on precedence,
432 # used by bround() and bfround(), may return undef for scale (means no op)
433 my ($x,$s,$m,$scale,$mode) = @_;
434 $scale = $x->{_p} if !defined $scale;
435 $scale = $s if (!defined $scale);
436 $mode = $m if !defined $mode;
437 return ($scale,$mode);
440 ##############################################################################
448 # if two arguments, the first one is the class to "swallow" subclasses
456 return unless ref($x); # only for objects
458 my $self = {}; bless $self,$c;
460 $self->{sign} = $x->{sign};
461 $self->{value} = $CALC->_copy($x->{value});
462 $self->{_a} = $x->{_a} if defined $x->{_a};
463 $self->{_p} = $x->{_p} if defined $x->{_p};
469 # create a new BigInt object from a string or another BigInt object.
470 # see hash keys documented at top
472 # the argument could be an object, so avoid ||, && etc on it, this would
473 # cause costly overloaded code to be called. The only allowed ops are
476 my ($class,$wanted,$a,$p,$r) = @_;
478 # avoid numify-calls by not using || on $wanted!
479 return $class->bzero($a,$p) if !defined $wanted; # default to 0
480 return $class->copy($wanted,$a,$p,$r)
481 if ref($wanted) && $wanted->isa($class); # MBI or subclass
483 $class->import() if $IMPORT == 0; # make require work
485 my $self = bless {}, $class;
487 # shortcut for "normal" numbers
488 if ((!ref $wanted) && ($wanted =~ /^([+-]?)[1-9][0-9]*\z/))
490 $self->{sign} = $1 || '+';
492 if ($wanted =~ /^[+-]/)
494 # remove sign without touching wanted to make it work with constants
495 my $t = $wanted; $t =~ s/^[+-]//;
496 $self->{value} = $CALC->_new($t);
500 $self->{value} = $CALC->_new($wanted);
503 if ( (defined $a) || (defined $p)
504 || (defined ${"${class}::precision"})
505 || (defined ${"${class}::accuracy"})
508 $self->round($a,$p,$r) unless (@_ == 4 && !defined $a && !defined $p);
513 # handle '+inf', '-inf' first
514 if ($wanted =~ /^[+-]?inf$/)
516 $self->{value} = $CALC->_zero();
517 $self->{sign} = $wanted; $self->{sign} = '+inf' if $self->{sign} eq 'inf';
520 # split str in m mantissa, e exponent, i integer, f fraction, v value, s sign
521 my ($mis,$miv,$mfv,$es,$ev) = _split($wanted);
526 require Carp; Carp::croak("$wanted is not a number in $class");
528 $self->{value} = $CALC->_zero();
529 $self->{sign} = $nan;
534 # _from_hex or _from_bin
535 $self->{value} = $mis->{value};
536 $self->{sign} = $mis->{sign};
537 return $self; # throw away $mis
539 # make integer from mantissa by adjusting exp, then convert to bigint
540 $self->{sign} = $$mis; # store sign
541 $self->{value} = $CALC->_zero(); # for all the NaN cases
542 my $e = int("$$es$$ev"); # exponent (avoid recursion)
545 my $diff = $e - CORE::length($$mfv);
546 if ($diff < 0) # Not integer
550 require Carp; Carp::croak("$wanted not an integer in $class");
553 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
554 $self->{sign} = $nan;
558 # adjust fraction and add it to value
559 #print "diff > 0 $$miv\n";
560 $$miv = $$miv . ($$mfv . '0' x $diff);
565 if ($$mfv ne '') # e <= 0
567 # fraction and negative/zero E => NOI
570 require Carp; Carp::croak("$wanted not an integer in $class");
572 #print "NOI 2 \$\$mfv '$$mfv'\n";
573 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
574 $self->{sign} = $nan;
578 # xE-y, and empty mfv
581 if ($$miv !~ s/0{$e}$//) # can strip so many zero's?
585 require Carp; Carp::croak("$wanted not an integer in $class");
588 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
589 $self->{sign} = $nan;
593 $self->{sign} = '+' if $$miv eq '0'; # normalize -0 => +0
594 $self->{value} = $CALC->_new($$miv) if $self->{sign} =~ /^[+-]$/;
595 # if any of the globals is set, use them to round and store them inside $self
596 # do not round for new($x,undef,undef) since that is used by MBF to signal
598 $self->round($a,$p,$r) unless @_ == 4 && !defined $a && !defined $p;
604 # create a bigint 'NaN', if given a BigInt, set it to 'NaN'
606 $self = $class if !defined $self;
609 my $c = $self; $self = {}; bless $self, $c;
612 if (${"${class}::_trap_nan"})
615 Carp::croak ("Tried to set $self to NaN in $class\::bnan()");
617 $self->import() if $IMPORT == 0; # make require work
618 return if $self->modify('bnan');
619 if ($self->can('_bnan'))
621 # use subclass to initialize
626 # otherwise do our own thing
627 $self->{value} = $CALC->_zero();
629 $self->{sign} = $nan;
630 delete $self->{_a}; delete $self->{_p}; # rounding NaN is silly
636 # create a bigint '+-inf', if given a BigInt, set it to '+-inf'
637 # the sign is either '+', or if given, used from there
639 my $sign = shift; $sign = '+' if !defined $sign || $sign !~ /^-(inf)?$/;
640 $self = $class if !defined $self;
643 my $c = $self; $self = {}; bless $self, $c;
646 if (${"${class}::_trap_inf"})
649 Carp::croak ("Tried to set $self to +-inf in $class\::binfn()");
651 $self->import() if $IMPORT == 0; # make require work
652 return if $self->modify('binf');
653 if ($self->can('_binf'))
655 # use subclass to initialize
660 # otherwise do our own thing
661 $self->{value} = $CALC->_zero();
663 $sign = $sign . 'inf' if $sign !~ /inf$/; # - => -inf
664 $self->{sign} = $sign;
665 ($self->{_a},$self->{_p}) = @_; # take over requested rounding
671 # create a bigint '+0', if given a BigInt, set it to 0
673 $self = $class if !defined $self;
677 my $c = $self; $self = {}; bless $self, $c;
679 $self->import() if $IMPORT == 0; # make require work
680 return if $self->modify('bzero');
682 if ($self->can('_bzero'))
684 # use subclass to initialize
689 # otherwise do our own thing
690 $self->{value} = $CALC->_zero();
697 # call like: $x->bzero($a,$p,$r,$y);
698 ($self,$self->{_a},$self->{_p}) = $self->_find_round_parameters(@_);
703 if ( (!defined $self->{_a}) || (defined $_[0] && $_[0] > $self->{_a}));
705 if ( (!defined $self->{_p}) || (defined $_[1] && $_[1] > $self->{_p}));
713 # create a bigint '+1' (or -1 if given sign '-'),
714 # if given a BigInt, set it to +1 or -1, respecively
716 my $sign = shift; $sign = '+' if !defined $sign || $sign ne '-';
717 $self = $class if !defined $self;
721 my $c = $self; $self = {}; bless $self, $c;
723 $self->import() if $IMPORT == 0; # make require work
724 return if $self->modify('bone');
726 if ($self->can('_bone'))
728 # use subclass to initialize
733 # otherwise do our own thing
734 $self->{value} = $CALC->_one();
736 $self->{sign} = $sign;
741 # call like: $x->bone($sign,$a,$p,$r,$y);
742 ($self,$self->{_a},$self->{_p}) = $self->_find_round_parameters(@_);
746 # call like: $x->bone($sign,$a,$p,$r);
748 if ( (!defined $self->{_a}) || (defined $_[0] && $_[0] > $self->{_a}));
750 if ( (!defined $self->{_p}) || (defined $_[1] && $_[1] > $self->{_p}));
756 ##############################################################################
757 # string conversation
761 # (ref to BFLOAT or num_str ) return num_str
762 # Convert number from internal format to scientific string format.
763 # internal format is always normalized (no leading zeros, "-0E0" => "+0E0")
764 my $x = shift; $class = ref($x) || $x; $x = $class->new(shift) if !ref($x);
765 # my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
767 if ($x->{sign} !~ /^[+-]$/)
769 return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
772 my ($m,$e) = $x->parts();
773 #$m->bstr() . 'e+' . $e->bstr(); # e can only be positive in BigInt
774 # 'e+' because E can only be positive in BigInt
775 $m->bstr() . 'e+' . $CALC->_str($e->{value});
780 # make a string from bigint object
781 my $x = shift; $class = ref($x) || $x; $x = $class->new(shift) if !ref($x);
782 # my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
784 if ($x->{sign} !~ /^[+-]$/)
786 return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
789 my $es = ''; $es = $x->{sign} if $x->{sign} eq '-';
790 $es.$CALC->_str($x->{value});
795 # Make a "normal" scalar from a BigInt object
796 my $x = shift; $x = $class->new($x) unless ref $x;
798 return $x->bstr() if $x->{sign} !~ /^[+-]$/;
799 my $num = $CALC->_num($x->{value});
800 return -$num if $x->{sign} eq '-';
804 ##############################################################################
805 # public stuff (usually prefixed with "b")
809 # return the sign of the number: +/-/-inf/+inf/NaN
810 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
815 sub _find_round_parameters
817 # After any operation or when calling round(), the result is rounded by
818 # regarding the A & P from arguments, local parameters, or globals.
820 # !!!!!!! If you change this, remember to change round(), too! !!!!!!!!!!
822 # This procedure finds the round parameters, but it is for speed reasons
823 # duplicated in round. Otherwise, it is tested by the testsuite and used
826 # returns ($self) or ($self,$a,$p,$r) - sets $self to NaN of both A and P
827 # were requested/defined (locally or globally or both)
829 my ($self,$a,$p,$r,@args) = @_;
830 # $a accuracy, if given by caller
831 # $p precision, if given by caller
832 # $r round_mode, if given by caller
833 # @args all 'other' arguments (0 for unary, 1 for binary ops)
835 # leave bigfloat parts alone
836 return ($self) if exists $self->{_f} && ($self->{_f} & MB_NEVER_ROUND) != 0;
838 my $c = ref($self); # find out class of argument(s)
841 # now pick $a or $p, but only if we have got "arguments"
844 foreach ($self,@args)
846 # take the defined one, or if both defined, the one that is smaller
847 $a = $_->{_a} if (defined $_->{_a}) && (!defined $a || $_->{_a} < $a);
852 # even if $a is defined, take $p, to signal error for both defined
853 foreach ($self,@args)
855 # take the defined one, or if both defined, the one that is bigger
857 $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} > $p);
860 # if still none defined, use globals (#2)
861 $a = ${"$c\::accuracy"} unless defined $a;
862 $p = ${"$c\::precision"} unless defined $p;
864 # A == 0 is useless, so undef it to signal no rounding
865 $a = undef if defined $a && $a == 0;
868 return ($self) unless defined $a || defined $p; # early out
870 # set A and set P is an fatal error
871 return ($self->bnan()) if defined $a && defined $p; # error
873 $r = ${"$c\::round_mode"} unless defined $r;
874 if ($r !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
876 require Carp; Carp::croak ("Unknown round mode '$r'");
884 # Round $self according to given parameters, or given second argument's
885 # parameters or global defaults
887 # for speed reasons, _find_round_parameters is embeded here:
889 my ($self,$a,$p,$r,@args) = @_;
890 # $a accuracy, if given by caller
891 # $p precision, if given by caller
892 # $r round_mode, if given by caller
893 # @args all 'other' arguments (0 for unary, 1 for binary ops)
895 # leave bigfloat parts alone
896 return ($self) if exists $self->{_f} && ($self->{_f} & MB_NEVER_ROUND) != 0;
898 my $c = ref($self); # find out class of argument(s)
901 # now pick $a or $p, but only if we have got "arguments"
904 foreach ($self,@args)
906 # take the defined one, or if both defined, the one that is smaller
907 $a = $_->{_a} if (defined $_->{_a}) && (!defined $a || $_->{_a} < $a);
912 # even if $a is defined, take $p, to signal error for both defined
913 foreach ($self,@args)
915 # take the defined one, or if both defined, the one that is bigger
917 $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} > $p);
920 # if still none defined, use globals (#2)
921 $a = ${"$c\::accuracy"} unless defined $a;
922 $p = ${"$c\::precision"} unless defined $p;
924 # A == 0 is useless, so undef it to signal no rounding
925 $a = undef if defined $a && $a == 0;
928 return $self unless defined $a || defined $p; # early out
930 # set A and set P is an fatal error
931 return $self->bnan() if defined $a && defined $p;
933 $r = ${"$c\::round_mode"} unless defined $r;
934 if ($r !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
936 require Carp; Carp::croak ("Unknown round mode '$r'");
939 # now round, by calling either fround or ffround:
942 $self->bround($a,$r) if !defined $self->{_a} || $self->{_a} >= $a;
944 else # both can't be undefined due to early out
946 $self->bfround($p,$r) if !defined $self->{_p} || $self->{_p} <= $p;
948 $self->bnorm(); # after round, normalize
953 # (numstr or BINT) return BINT
954 # Normalize number -- no-op here
955 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
961 # (BINT or num_str) return BINT
962 # make number absolute, or return absolute BINT from string
963 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
965 return $x if $x->modify('babs');
966 # post-normalized abs for internal use (does nothing for NaN)
967 $x->{sign} =~ s/^-/+/;
973 # (BINT or num_str) return BINT
974 # negate number or make a negated number from string
975 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
977 return $x if $x->modify('bneg');
979 # for +0 dont negate (to have always normalized)
980 $x->{sign} =~ tr/+-/-+/ if !$x->is_zero(); # does nothing for NaN
986 # Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort)
987 # (BINT or num_str, BINT or num_str) return cond_code
990 my ($self,$x,$y) = (ref($_[0]),@_);
992 # objectify is costly, so avoid it
993 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
995 ($self,$x,$y) = objectify(2,@_);
998 return $upgrade->bcmp($x,$y) if defined $upgrade &&
999 ((!$x->isa($self)) || (!$y->isa($self)));
1001 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1003 # handle +-inf and NaN
1004 return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1005 return 0 if $x->{sign} eq $y->{sign} && $x->{sign} =~ /^[+-]inf$/;
1006 return +1 if $x->{sign} eq '+inf';
1007 return -1 if $x->{sign} eq '-inf';
1008 return -1 if $y->{sign} eq '+inf';
1011 # check sign for speed first
1012 return 1 if $x->{sign} eq '+' && $y->{sign} eq '-'; # does also 0 <=> -y
1013 return -1 if $x->{sign} eq '-' && $y->{sign} eq '+'; # does also -x <=> 0
1015 # have same sign, so compare absolute values. Don't make tests for zero here
1016 # because it's actually slower than testin in Calc (especially w/ Pari et al)
1018 # post-normalized compare for internal use (honors signs)
1019 if ($x->{sign} eq '+')
1021 # $x and $y both > 0
1022 return $CALC->_acmp($x->{value},$y->{value});
1026 $CALC->_acmp($y->{value},$x->{value}); # swaped acmp (lib returns 0,1,-1)
1031 # Compares 2 values, ignoring their signs.
1032 # Returns one of undef, <0, =0, >0. (suitable for sort)
1033 # (BINT, BINT) return cond_code
1036 my ($self,$x,$y) = (ref($_[0]),@_);
1037 # objectify is costly, so avoid it
1038 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1040 ($self,$x,$y) = objectify(2,@_);
1043 return $upgrade->bacmp($x,$y) if defined $upgrade &&
1044 ((!$x->isa($self)) || (!$y->isa($self)));
1046 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1048 # handle +-inf and NaN
1049 return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1050 return 0 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} =~ /^[+-]inf$/;
1051 return 1 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} !~ /^[+-]inf$/;
1054 $CALC->_acmp($x->{value},$y->{value}); # lib does only 0,1,-1
1059 # add second arg (BINT or string) to first (BINT) (modifies first)
1060 # return result as BINT
1063 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1064 # objectify is costly, so avoid it
1065 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1067 ($self,$x,$y,@r) = objectify(2,@_);
1070 return $x if $x->modify('badd');
1071 return $upgrade->badd($upgrade->new($x),$upgrade->new($y),@r) if defined $upgrade &&
1072 ((!$x->isa($self)) || (!$y->isa($self)));
1074 $r[3] = $y; # no push!
1075 # inf and NaN handling
1076 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1079 return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1081 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1083 # +inf++inf or -inf+-inf => same, rest is NaN
1084 return $x if $x->{sign} eq $y->{sign};
1087 # +-inf + something => +inf
1088 # something +-inf => +-inf
1089 $x->{sign} = $y->{sign}, return $x if $y->{sign} =~ /^[+-]inf$/;
1093 my ($sx, $sy) = ( $x->{sign}, $y->{sign} ); # get signs
1097 $x->{value} = $CALC->_add($x->{value},$y->{value}); # same sign, abs add
1101 my $a = $CALC->_acmp ($y->{value},$x->{value}); # absolute compare
1104 $x->{value} = $CALC->_sub($y->{value},$x->{value},1); # abs sub w/ swap
1109 # speedup, if equal, set result to 0
1110 $x->{value} = $CALC->_zero();
1115 $x->{value} = $CALC->_sub($x->{value}, $y->{value}); # abs sub
1118 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1124 # (BINT or num_str, BINT or num_str) return BINT
1125 # subtract second arg from first, modify first
1128 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1129 # objectify is costly, so avoid it
1130 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1132 ($self,$x,$y,@r) = objectify(2,@_);
1135 return $x if $x->modify('bsub');
1137 return $upgrade->new($x)->bsub($upgrade->new($y),@r) if defined $upgrade &&
1138 ((!$x->isa($self)) || (!$y->isa($self)));
1142 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1146 require Scalar::Util;
1147 if (Scalar::Util::refaddr($x) == Scalar::Util::refaddr($y))
1149 # if we get the same variable twice, the result must be zero (the code
1150 # below fails in that case)
1151 return $x->bzero(@r) if $x->{sign} =~ /^[+-]$/;
1152 return $x->bnan(); # NaN, -inf, +inf
1154 $y->{sign} =~ tr/+\-/-+/; # does nothing for NaN
1155 $x->badd($y,@r); # badd does not leave internal zeros
1156 $y->{sign} =~ tr/+\-/-+/; # refix $y (does nothing for NaN)
1157 $x; # already rounded by badd() or no round necc.
1162 # increment arg by one
1163 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1164 return $x if $x->modify('binc');
1166 if ($x->{sign} eq '+')
1168 $x->{value} = $CALC->_inc($x->{value});
1169 $x->round($a,$p,$r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1172 elsif ($x->{sign} eq '-')
1174 $x->{value} = $CALC->_dec($x->{value});
1175 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # -1 +1 => -0 => +0
1176 $x->round($a,$p,$r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1179 # inf, nan handling etc
1180 $x->badd($self->bone(),$a,$p,$r); # badd does round
1185 # decrement arg by one
1186 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1187 return $x if $x->modify('bdec');
1189 if ($x->{sign} eq '-')
1192 $x->{value} = $CALC->_inc($x->{value});
1196 return $x->badd($self->bone('-'),@r) unless $x->{sign} eq '+'; # inf/NaN
1198 if ($CALC->_is_zero($x->{value}))
1201 $x->{value} = $CALC->_one(); $x->{sign} = '-'; # 0 => -1
1206 $x->{value} = $CALC->_dec($x->{value});
1209 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1215 # calculate $x = $a ** $base + $b and return $a (e.g. the log() to base
1219 my ($self,$x,$base,@r) = (ref($_[0]),@_);
1220 # objectify is costly, so avoid it
1221 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1223 ($self,$x,$base,@r) = objectify(1,$class,@_);
1226 return $x if $x->modify('blog');
1228 # inf, -inf, NaN, <0 => NaN
1230 if $x->{sign} ne '+' || (defined $base && $base->{sign} ne '+');
1232 return $upgrade->blog($upgrade->new($x),$base,@r) if
1235 my ($rc,$exact) = $CALC->_log_int($x->{value},$base->{value});
1236 return $x->bnan() unless defined $rc; # not possible to take log?
1243 # (BINT or num_str, BINT or num_str) return BINT
1244 # does not modify arguments, but returns new object
1245 # Lowest Common Multiplicator
1247 my $y = shift; my ($x);
1254 $x = __PACKAGE__->new($y);
1259 my $y = shift; $y = $self->new($y) if !ref ($y);
1267 # (BINT or num_str, BINT or num_str) return BINT
1268 # does not modify arguments, but returns new object
1269 # GCD -- Euclids algorithm, variant C (Knuth Vol 3, pg 341 ff)
1272 $y = __PACKAGE__->new($y) if !ref($y);
1274 my $x = $y->copy()->babs(); # keep arguments
1275 return $x->bnan() if $x->{sign} !~ /^[+-]$/; # x NaN?
1279 $y = shift; $y = $self->new($y) if !ref($y);
1280 next if $y->is_zero();
1281 return $x->bnan() if $y->{sign} !~ /^[+-]$/; # y NaN?
1282 $x->{value} = $CALC->_gcd($x->{value},$y->{value}); last if $x->is_one();
1289 # (num_str or BINT) return BINT
1290 # represent ~x as twos-complement number
1291 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1292 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1294 return $x if $x->modify('bnot');
1295 $x->binc()->bneg(); # binc already does round
1298 ##############################################################################
1299 # is_foo test routines
1300 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1304 # return true if arg (BINT or num_str) is zero (array '+', '0')
1305 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1307 return 0 if $x->{sign} !~ /^\+$/; # -, NaN & +-inf aren't
1308 $CALC->_is_zero($x->{value});
1313 # return true if arg (BINT or num_str) is NaN
1314 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1316 $x->{sign} eq $nan ? 1 : 0;
1321 # return true if arg (BINT or num_str) is +-inf
1322 my ($self,$x,$sign) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1326 $sign = '[+-]inf' if $sign eq ''; # +- doesn't matter, only that's inf
1327 $sign = "[$1]inf" if $sign =~ /^([+-])(inf)?$/; # extract '+' or '-'
1328 return $x->{sign} =~ /^$sign$/ ? 1 : 0;
1330 $x->{sign} =~ /^[+-]inf$/ ? 1 : 0; # only +-inf is infinity
1335 # return true if arg (BINT or num_str) is +1, or -1 if sign is given
1336 my ($self,$x,$sign) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1338 $sign = '+' if !defined $sign || $sign ne '-';
1340 return 0 if $x->{sign} ne $sign; # -1 != +1, NaN, +-inf aren't either
1341 $CALC->_is_one($x->{value});
1346 # return true when arg (BINT or num_str) is odd, false for even
1347 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1349 return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
1350 $CALC->_is_odd($x->{value});
1355 # return true when arg (BINT or num_str) is even, false for odd
1356 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1358 return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
1359 $CALC->_is_even($x->{value});
1364 # return true when arg (BINT or num_str) is positive (>= 0)
1365 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1367 $x->{sign} =~ /^\+/ ? 1 : 0; # +inf is also positive, but NaN not
1372 # return true when arg (BINT or num_str) is negative (< 0)
1373 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1375 $x->{sign} =~ /^-/ ? 1 : 0; # -inf is also negative, but NaN not
1380 # return true when arg (BINT or num_str) is an integer
1381 # always true for BigInt, but different for BigFloats
1382 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1384 $x->{sign} =~ /^[+-]$/ ? 1 : 0; # inf/-inf/NaN aren't
1387 ###############################################################################
1391 # multiply two numbers -- stolen from Knuth Vol 2 pg 233
1392 # (BINT or num_str, BINT or num_str) return BINT
1395 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1396 # objectify is costly, so avoid it
1397 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1399 ($self,$x,$y,@r) = objectify(2,@_);
1402 return $x if $x->modify('bmul');
1404 return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1407 if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
1409 return $x->bnan() if $x->is_zero() || $y->is_zero();
1410 # result will always be +-inf:
1411 # +inf * +/+inf => +inf, -inf * -/-inf => +inf
1412 # +inf * -/-inf => -inf, -inf * +/+inf => -inf
1413 return $x->binf() if ($x->{sign} =~ /^\+/ && $y->{sign} =~ /^\+/);
1414 return $x->binf() if ($x->{sign} =~ /^-/ && $y->{sign} =~ /^-/);
1415 return $x->binf('-');
1418 return $upgrade->bmul($x,$upgrade->new($y),@r)
1419 if defined $upgrade && !$y->isa($self);
1421 $r[3] = $y; # no push here
1423 $x->{sign} = $x->{sign} eq $y->{sign} ? '+' : '-'; # +1 * +1 or -1 * -1 => +
1425 $x->{value} = $CALC->_mul($x->{value},$y->{value}); # do actual math
1426 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # no -0
1428 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1434 # helper function that handles +-inf cases for bdiv()/bmod() to reuse code
1435 my ($self,$x,$y) = @_;
1437 # NaN if x == NaN or y == NaN or x==y==0
1438 return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan()
1439 if (($x->is_nan() || $y->is_nan()) ||
1440 ($x->is_zero() && $y->is_zero()));
1442 # +-inf / +-inf == NaN, reminder also NaN
1443 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1445 return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan();
1447 # x / +-inf => 0, remainder x (works even if x == 0)
1448 if ($y->{sign} =~ /^[+-]inf$/)
1450 my $t = $x->copy(); # bzero clobbers up $x
1451 return wantarray ? ($x->bzero(),$t) : $x->bzero()
1454 # 5 / 0 => +inf, -6 / 0 => -inf
1455 # +inf / 0 = inf, inf, and -inf / 0 => -inf, -inf
1456 # exception: -8 / 0 has remainder -8, not 8
1457 # exception: -inf / 0 has remainder -inf, not inf
1460 # +-inf / 0 => special case for -inf
1461 return wantarray ? ($x,$x->copy()) : $x if $x->is_inf();
1462 if (!$x->is_zero() && !$x->is_inf())
1464 my $t = $x->copy(); # binf clobbers up $x
1466 ($x->binf($x->{sign}),$t) : $x->binf($x->{sign})
1470 # last case: +-inf / ordinary number
1472 $sign = '-inf' if substr($x->{sign},0,1) ne $y->{sign};
1474 return wantarray ? ($x,$self->bzero()) : $x;
1479 # (dividend: BINT or num_str, divisor: BINT or num_str) return
1480 # (BINT,BINT) (quo,rem) or BINT (only rem)
1483 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1484 # objectify is costly, so avoid it
1485 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1487 ($self,$x,$y,@r) = objectify(2,@_);
1490 return $x if $x->modify('bdiv');
1492 return $self->_div_inf($x,$y)
1493 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero());
1495 return $upgrade->bdiv($upgrade->new($x),$upgrade->new($y),@r)
1496 if defined $upgrade;
1498 $r[3] = $y; # no push!
1500 # calc new sign and in case $y == +/- 1, return $x
1501 my $xsign = $x->{sign}; # keep
1502 $x->{sign} = ($x->{sign} ne $y->{sign} ? '-' : '+');
1506 my $rem = $self->bzero();
1507 ($x->{value},$rem->{value}) = $CALC->_div($x->{value},$y->{value});
1508 $x->{sign} = '+' if $CALC->_is_zero($x->{value});
1509 $rem->{_a} = $x->{_a};
1510 $rem->{_p} = $x->{_p};
1511 $x->round(@r) if !exists $x->{_f} || ($x->{_f} & MB_NEVER_ROUND) == 0;
1512 if (! $CALC->_is_zero($rem->{value}))
1514 $rem->{sign} = $y->{sign};
1515 $rem = $y->copy()->bsub($rem) if $xsign ne $y->{sign}; # one of them '-'
1519 $rem->{sign} = '+'; # dont leave -0
1521 $rem->round(@r) if !exists $rem->{_f} || ($rem->{_f} & MB_NEVER_ROUND) == 0;
1525 $x->{value} = $CALC->_div($x->{value},$y->{value});
1526 $x->{sign} = '+' if $CALC->_is_zero($x->{value});
1528 $x->round(@r) if !exists $x->{_f} || ($x->{_f} & MB_NEVER_ROUND) == 0;
1532 ###############################################################################
1537 # modulus (or remainder)
1538 # (BINT or num_str, BINT or num_str) return BINT
1541 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1542 # objectify is costly, so avoid it
1543 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1545 ($self,$x,$y,@r) = objectify(2,@_);
1548 return $x if $x->modify('bmod');
1549 $r[3] = $y; # no push!
1550 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero())
1552 my ($d,$r) = $self->_div_inf($x,$y);
1553 $x->{sign} = $r->{sign};
1554 $x->{value} = $r->{value};
1555 return $x->round(@r);
1558 # calc new sign and in case $y == +/- 1, return $x
1559 $x->{value} = $CALC->_mod($x->{value},$y->{value});
1560 if (!$CALC->_is_zero($x->{value}))
1562 my $xsign = $x->{sign};
1563 $x->{sign} = $y->{sign};
1564 if ($xsign ne $y->{sign})
1566 my $t = $CALC->_copy($x->{value}); # copy $x
1567 $x->{value} = $CALC->_sub($y->{value},$t,1); # $y-$x
1572 $x->{sign} = '+'; # dont leave -0
1574 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1580 # Modular inverse. given a number which is (hopefully) relatively
1581 # prime to the modulus, calculate its inverse using Euclid's
1582 # alogrithm. If the number is not relatively prime to the modulus
1583 # (i.e. their gcd is not one) then NaN is returned.
1586 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1587 # objectify is costly, so avoid it
1588 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1590 ($self,$x,$y,@r) = objectify(2,@_);
1593 return $x if $x->modify('bmodinv');
1596 if ($y->{sign} ne '+' # -, NaN, +inf, -inf
1597 || $x->is_zero() # or num == 0
1598 || $x->{sign} !~ /^[+-]$/ # or num NaN, inf, -inf
1601 # put least residue into $x if $x was negative, and thus make it positive
1602 $x->bmod($y) if $x->{sign} eq '-';
1605 ($x->{value},$sign) = $CALC->_modinv($x->{value},$y->{value});
1606 return $x->bnan() if !defined $x->{value}; # in case no GCD found
1607 return $x if !defined $sign; # already real result
1608 $x->{sign} = $sign; # flip/flop see below
1609 $x->bmod($y); # calc real result
1615 # takes a very large number to a very large exponent in a given very
1616 # large modulus, quickly, thanks to binary exponentation. supports
1617 # negative exponents.
1618 my ($self,$num,$exp,$mod,@r) = objectify(3,@_);
1620 return $num if $num->modify('bmodpow');
1622 # check modulus for valid values
1623 return $num->bnan() if ($mod->{sign} ne '+' # NaN, - , -inf, +inf
1624 || $mod->is_zero());
1626 # check exponent for valid values
1627 if ($exp->{sign} =~ /\w/)
1629 # i.e., if it's NaN, +inf, or -inf...
1630 return $num->bnan();
1633 $num->bmodinv ($mod) if ($exp->{sign} eq '-');
1635 # check num for valid values (also NaN if there was no inverse but $exp < 0)
1636 return $num->bnan() if $num->{sign} !~ /^[+-]$/;
1638 # $mod is positive, sign on $exp is ignored, result also positive
1639 $num->{value} = $CALC->_modpow($num->{value},$exp->{value},$mod->{value});
1643 ###############################################################################
1647 # (BINT or num_str, BINT or num_str) return BINT
1648 # compute factorial number from $x, modify $x in place
1649 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1651 return $x if $x->modify('bfac');
1653 return $x if $x->{sign} eq '+inf'; # inf => inf
1654 return $x->bnan() if $x->{sign} ne '+'; # NaN, <0 etc => NaN
1656 $x->{value} = $CALC->_fac($x->{value});
1662 # (BINT or num_str, BINT or num_str) return BINT
1663 # compute power of two numbers -- stolen from Knuth Vol 2 pg 233
1664 # modifies first argument
1667 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1668 # objectify is costly, so avoid it
1669 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1671 ($self,$x,$y,@r) = objectify(2,@_);
1674 return $x if $x->modify('bpow');
1676 return $x->bnan() if $x->{sign} eq $nan || $y->{sign} eq $nan;
1679 if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
1681 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1687 if ($x->{sign} =~ /^[+-]inf/)
1690 return $x->bnan() if $y->is_zero();
1691 # -inf ** -1 => 1/inf => 0
1692 return $x->bzero() if $y->is_one('-') && $x->is_negative();
1695 return $x if $x->{sign} eq '+inf';
1697 # -inf ** Y => -inf if Y is odd
1698 return $x if $y->is_odd();
1704 return $x if $x->is_one();
1707 return $x if $x->is_zero() && $y->{sign} =~ /^[+]/;
1710 return $x->binf() if $x->is_zero();
1713 return $x->bnan() if $x->is_one('-') && $y->{sign} =~ /^[-]/;
1716 return $x->bzero() if $x->{sign} eq '-' && $y->{sign} =~ /^[-]/;
1719 return $x->bnan() if $x->{sign} eq '-';
1722 return $x->binf() if $y->{sign} =~ /^[+]/;
1727 return $upgrade->bpow($upgrade->new($x),$y,@r)
1728 if defined $upgrade && !$y->isa($self);
1730 $r[3] = $y; # no push!
1732 # cases 0 ** Y, X ** 0, X ** 1, 1 ** Y are handled by Calc or Emu
1735 $new_sign = $y->is_odd() ? '-' : '+' if ($x->{sign} ne '+');
1737 # 0 ** -7 => ( 1 / (0 ** 7)) => 1 / 0 => +inf
1739 if $y->{sign} eq '-' && $x->{sign} eq '+' && $CALC->_is_zero($x->{value});
1740 # 1 ** -y => 1 / (1 ** |y|)
1741 # so do test for negative $y after above's clause
1742 return $x->bnan() if $y->{sign} eq '-' && !$CALC->_is_one($x->{value});
1744 $x->{value} = $CALC->_pow($x->{value},$y->{value});
1745 $x->{sign} = $new_sign;
1746 $x->{sign} = '+' if $CALC->_is_zero($y->{value});
1747 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1753 # (BINT or num_str, BINT or num_str) return BINT
1754 # compute x << y, base n, y >= 0
1757 my ($self,$x,$y,$n,@r) = (ref($_[0]),@_);
1758 # objectify is costly, so avoid it
1759 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1761 ($self,$x,$y,$n,@r) = objectify(2,@_);
1764 return $x if $x->modify('blsft');
1765 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1766 return $x->round(@r) if $y->is_zero();
1768 $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
1770 $x->{value} = $CALC->_lsft($x->{value},$y->{value},$n);
1776 # (BINT or num_str, BINT or num_str) return BINT
1777 # compute x >> y, base n, y >= 0
1780 my ($self,$x,$y,$n,@r) = (ref($_[0]),@_);
1781 # objectify is costly, so avoid it
1782 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1784 ($self,$x,$y,$n,@r) = objectify(2,@_);
1787 return $x if $x->modify('brsft');
1788 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1789 return $x->round(@r) if $y->is_zero();
1790 return $x->bzero(@r) if $x->is_zero(); # 0 => 0
1792 $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
1794 # this only works for negative numbers when shifting in base 2
1795 if (($x->{sign} eq '-') && ($n == 2))
1797 return $x->round(@r) if $x->is_one('-'); # -1 => -1
1800 # although this is O(N*N) in calc (as_bin!) it is O(N) in Pari et al
1801 # but perhaps there is a better emulation for two's complement shift...
1802 # if $y != 1, we must simulate it by doing:
1803 # convert to bin, flip all bits, shift, and be done
1804 $x->binc(); # -3 => -2
1805 my $bin = $x->as_bin();
1806 $bin =~ s/^-0b//; # strip '-0b' prefix
1807 $bin =~ tr/10/01/; # flip bits
1809 if (CORE::length($bin) <= $y)
1811 $bin = '0'; # shifting to far right creates -1
1812 # 0, because later increment makes
1813 # that 1, attached '-' makes it '-1'
1814 # because -1 >> x == -1 !
1818 $bin =~ s/.{$y}$//; # cut off at the right side
1819 $bin = '1' . $bin; # extend left side by one dummy '1'
1820 $bin =~ tr/10/01/; # flip bits back
1822 my $res = $self->new('0b'.$bin); # add prefix and convert back
1823 $res->binc(); # remember to increment
1824 $x->{value} = $res->{value}; # take over value
1825 return $x->round(@r); # we are done now, magic, isn't?
1827 # x < 0, n == 2, y == 1
1828 $x->bdec(); # n == 2, but $y == 1: this fixes it
1831 $x->{value} = $CALC->_rsft($x->{value},$y->{value},$n);
1837 #(BINT or num_str, BINT or num_str) return BINT
1841 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1842 # objectify is costly, so avoid it
1843 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1845 ($self,$x,$y,@r) = objectify(2,@_);
1848 return $x if $x->modify('band');
1850 $r[3] = $y; # no push!
1852 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1854 my $sx = $x->{sign} eq '+' ? 1 : -1;
1855 my $sy = $y->{sign} eq '+' ? 1 : -1;
1857 if ($sx == 1 && $sy == 1)
1859 $x->{value} = $CALC->_and($x->{value},$y->{value});
1860 return $x->round(@r);
1863 if ($CAN{signed_and})
1865 $x->{value} = $CALC->_signed_and($x->{value},$y->{value},$sx,$sy);
1866 return $x->round(@r);
1870 __emu_band($self,$x,$y,$sx,$sy,@r);
1875 #(BINT or num_str, BINT or num_str) return BINT
1879 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1880 # objectify is costly, so avoid it
1881 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1883 ($self,$x,$y,@r) = objectify(2,@_);
1886 return $x if $x->modify('bior');
1887 $r[3] = $y; # no push!
1889 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1891 my $sx = $x->{sign} eq '+' ? 1 : -1;
1892 my $sy = $y->{sign} eq '+' ? 1 : -1;
1894 # the sign of X follows the sign of X, e.g. sign of Y irrelevant for bior()
1896 # don't use lib for negative values
1897 if ($sx == 1 && $sy == 1)
1899 $x->{value} = $CALC->_or($x->{value},$y->{value});
1900 return $x->round(@r);
1903 # if lib can do negative values, let it handle this
1904 if ($CAN{signed_or})
1906 $x->{value} = $CALC->_signed_or($x->{value},$y->{value},$sx,$sy);
1907 return $x->round(@r);
1911 __emu_bior($self,$x,$y,$sx,$sy,@r);
1916 #(BINT or num_str, BINT or num_str) return BINT
1920 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1921 # objectify is costly, so avoid it
1922 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1924 ($self,$x,$y,@r) = objectify(2,@_);
1927 return $x if $x->modify('bxor');
1928 $r[3] = $y; # no push!
1930 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1932 my $sx = $x->{sign} eq '+' ? 1 : -1;
1933 my $sy = $y->{sign} eq '+' ? 1 : -1;
1935 # don't use lib for negative values
1936 if ($sx == 1 && $sy == 1)
1938 $x->{value} = $CALC->_xor($x->{value},$y->{value});
1939 return $x->round(@r);
1942 # if lib can do negative values, let it handle this
1943 if ($CAN{signed_xor})
1945 $x->{value} = $CALC->_signed_xor($x->{value},$y->{value},$sx,$sy);
1946 return $x->round(@r);
1950 __emu_bxor($self,$x,$y,$sx,$sy,@r);
1955 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1957 my $e = $CALC->_len($x->{value});
1958 wantarray ? ($e,0) : $e;
1963 # return the nth decimal digit, negative values count backward, 0 is right
1964 my ($self,$x,$n) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1966 $n = $n->numify() if ref($n);
1967 $CALC->_digit($x->{value},$n||0);
1972 # return the amount of trailing zeros in $x (as scalar)
1974 $x = $class->new($x) unless ref $x;
1976 return 0 if $x->{sign} !~ /^[+-]$/; # NaN, inf, -inf etc
1978 $CALC->_zeros($x->{value}); # must handle odd values, 0 etc
1983 # calculate square root of $x
1984 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1986 return $x if $x->modify('bsqrt');
1988 return $x->bnan() if $x->{sign} !~ /^\+/; # -x or -inf or NaN => NaN
1989 return $x if $x->{sign} eq '+inf'; # sqrt(+inf) == inf
1991 return $upgrade->bsqrt($x,@r) if defined $upgrade;
1993 $x->{value} = $CALC->_sqrt($x->{value});
1999 # calculate $y'th root of $x
2002 my ($self,$x,$y,@r) = (ref($_[0]),@_);
2004 $y = $self->new(2) unless defined $y;
2006 # objectify is costly, so avoid it
2007 if ((!ref($x)) || (ref($x) ne ref($y)))
2009 ($self,$x,$y,@r) = objectify(2,$self || $class,@_);
2012 return $x if $x->modify('broot');
2014 # NaN handling: $x ** 1/0, x or y NaN, or y inf/-inf or y == 0
2015 return $x->bnan() if $x->{sign} !~ /^\+/ || $y->is_zero() ||
2016 $y->{sign} !~ /^\+$/;
2018 return $x->round(@r)
2019 if $x->is_zero() || $x->is_one() || $x->is_inf() || $y->is_one();
2021 return $upgrade->new($x)->broot($upgrade->new($y),@r) if defined $upgrade;
2023 $x->{value} = $CALC->_root($x->{value},$y->{value});
2029 # return a copy of the exponent (here always 0, NaN or 1 for $m == 0)
2030 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2032 if ($x->{sign} !~ /^[+-]$/)
2034 my $s = $x->{sign}; $s =~ s/^[+-]//; # NaN, -inf,+inf => NaN or inf
2035 return $self->new($s);
2037 return $self->bone() if $x->is_zero();
2039 $self->new($x->_trailing_zeros());
2044 # return the mantissa (compatible to Math::BigFloat, e.g. reduced)
2045 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2047 if ($x->{sign} !~ /^[+-]$/)
2049 # for NaN, +inf, -inf: keep the sign
2050 return $self->new($x->{sign});
2052 my $m = $x->copy(); delete $m->{_p}; delete $m->{_a};
2053 # that's a bit inefficient:
2054 my $zeros = $m->_trailing_zeros();
2055 $m->brsft($zeros,10) if $zeros != 0;
2061 # return a copy of both the exponent and the mantissa
2062 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
2064 ($x->mantissa(),$x->exponent());
2067 ##############################################################################
2068 # rounding functions
2072 # precision: round to the $Nth digit left (+$n) or right (-$n) from the '.'
2073 # $n == 0 || $n == 1 => round to integer
2074 my $x = shift; my $self = ref($x) || $x; $x = $self->new($x) unless ref $x;
2076 my ($scale,$mode) = $x->_scale_p($x->precision(),$x->round_mode(),@_);
2078 return $x if !defined $scale || $x->modify('bfround'); # no-op
2080 # no-op for BigInts if $n <= 0
2081 $x->bround( $x->length()-$scale, $mode) if $scale > 0;
2083 delete $x->{_a}; # delete to save memory
2084 $x->{_p} = $scale; # store new _p
2088 sub _scan_for_nonzero
2090 # internal, used by bround() to scan for non-zeros after a '5'
2091 my ($x,$pad,$xs,$len) = @_;
2093 return 0 if $len == 1; # "5" is trailed by invisible zeros
2094 my $follow = $pad - 1;
2095 return 0 if $follow > $len || $follow < 1;
2097 # use the string form to check whether only '0's follow or not
2098 substr ($xs,-$follow) =~ /[^0]/ ? 1 : 0;
2103 # Exists to make life easier for switch between MBF and MBI (should we
2104 # autoload fxxx() like MBF does for bxxx()?)
2111 # accuracy: +$n preserve $n digits from left,
2112 # -$n preserve $n digits from right (f.i. for 0.1234 style in MBF)
2114 # and overwrite the rest with 0's, return normalized number
2115 # do not return $x->bnorm(), but $x
2117 my $x = shift; $x = $class->new($x) unless ref $x;
2118 my ($scale,$mode) = $x->_scale_a($x->accuracy(),$x->round_mode(),@_);
2119 return $x if !defined $scale; # no-op
2120 return $x if $x->modify('bround');
2122 if ($x->is_zero() || $scale == 0)
2124 $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale; # 3 > 2
2127 return $x if $x->{sign} !~ /^[+-]$/; # inf, NaN
2129 # we have fewer digits than we want to scale to
2130 my $len = $x->length();
2131 # convert $scale to a scalar in case it is an object (put's a limit on the
2132 # number length, but this would already limited by memory constraints), makes
2134 $scale = $scale->numify() if ref ($scale);
2136 # scale < 0, but > -len (not >=!)
2137 if (($scale < 0 && $scale < -$len-1) || ($scale >= $len))
2139 $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale; # 3 > 2
2143 # count of 0's to pad, from left (+) or right (-): 9 - +6 => 3, or |-6| => 6
2144 my ($pad,$digit_round,$digit_after);
2145 $pad = $len - $scale;
2146 $pad = abs($scale-1) if $scale < 0;
2148 # do not use digit(), it is very costly for binary => decimal
2149 # getting the entire string is also costly, but we need to do it only once
2150 my $xs = $CALC->_str($x->{value});
2153 # pad: 123: 0 => -1, at 1 => -2, at 2 => -3, at 3 => -4
2154 # pad+1: 123: 0 => 0, at 1 => -1, at 2 => -2, at 3 => -3
2155 $digit_round = '0'; $digit_round = substr($xs,$pl,1) if $pad <= $len;
2156 $pl++; $pl ++ if $pad >= $len;
2157 $digit_after = '0'; $digit_after = substr($xs,$pl,1) if $pad > 0;
2159 # in case of 01234 we round down, for 6789 up, and only in case 5 we look
2160 # closer at the remaining digits of the original $x, remember decision
2161 my $round_up = 1; # default round up
2163 ($mode eq 'trunc') || # trunc by round down
2164 ($digit_after =~ /[01234]/) || # round down anyway,
2166 ($digit_after eq '5') && # not 5000...0000
2167 ($x->_scan_for_nonzero($pad,$xs,$len) == 0) &&
2169 ($mode eq 'even') && ($digit_round =~ /[24680]/) ||
2170 ($mode eq 'odd') && ($digit_round =~ /[13579]/) ||
2171 ($mode eq '+inf') && ($x->{sign} eq '-') ||
2172 ($mode eq '-inf') && ($x->{sign} eq '+') ||
2173 ($mode eq 'zero') # round down if zero, sign adjusted below
2175 my $put_back = 0; # not yet modified
2177 if (($pad > 0) && ($pad <= $len))
2179 substr($xs,-$pad,$pad) = '0' x $pad; # replace with '00...'
2180 $put_back = 1; # need to put back
2184 $x->bzero(); # round to '0'
2187 if ($round_up) # what gave test above?
2189 $put_back = 1; # need to put back
2190 $pad = $len, $xs = '0' x $pad if $scale < 0; # tlr: whack 0.51=>1.0
2192 # we modify directly the string variant instead of creating a number and
2193 # adding it, since that is faster (we already have the string)
2194 my $c = 0; $pad ++; # for $pad == $len case
2195 while ($pad <= $len)
2197 $c = substr($xs,-$pad,1) + 1; $c = '0' if $c eq '10';
2198 substr($xs,-$pad,1) = $c; $pad++;
2199 last if $c != 0; # no overflow => early out
2201 $xs = '1'.$xs if $c == 0;
2204 $x->{value} = $CALC->_new($xs) if $put_back == 1; # put back, if needed
2206 $x->{_a} = $scale if $scale >= 0;
2209 $x->{_a} = $len+$scale;
2210 $x->{_a} = 0 if $scale < -$len;
2217 # return integer less or equal then number; no-op since it's already integer
2218 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2225 # return integer greater or equal then number; no-op since it's already int
2226 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2233 # An object might be asked to return itself as bigint on certain overloaded
2234 # operations, this does exactly this, so that sub classes can simple inherit
2235 # it or override with their own integer conversion routine.
2241 # return as hex string, with prefixed 0x
2242 my $x = shift; $x = $class->new($x) if !ref($x);
2244 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2247 $s = $x->{sign} if $x->{sign} eq '-';
2248 $s . $CALC->_as_hex($x->{value});
2253 # return as binary string, with prefixed 0b
2254 my $x = shift; $x = $class->new($x) if !ref($x);
2256 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2258 my $s = ''; $s = $x->{sign} if $x->{sign} eq '-';
2259 return $s . $CALC->_as_bin($x->{value});
2262 ##############################################################################
2263 # private stuff (internal use only)
2267 # check for strings, if yes, return objects instead
2269 # the first argument is number of args objectify() should look at it will
2270 # return $count+1 elements, the first will be a classname. This is because
2271 # overloaded '""' calls bstr($object,undef,undef) and this would result in
2272 # useless objects beeing created and thrown away. So we cannot simple loop
2273 # over @_. If the given count is 0, all arguments will be used.
2275 # If the second arg is a ref, use it as class.
2276 # If not, try to use it as classname, unless undef, then use $class
2277 # (aka Math::BigInt). The latter shouldn't happen,though.
2280 # $x->badd(1); => ref x, scalar y
2281 # Class->badd(1,2); => classname x (scalar), scalar x, scalar y
2282 # Class->badd( Class->(1),2); => classname x (scalar), ref x, scalar y
2283 # Math::BigInt::badd(1,2); => scalar x, scalar y
2284 # In the last case we check number of arguments to turn it silently into
2285 # $class,1,2. (We can not take '1' as class ;o)
2286 # badd($class,1) is not supported (it should, eventually, try to add undef)
2287 # currently it tries 'Math::BigInt' + 1, which will not work.
2289 # some shortcut for the common cases
2291 return (ref($_[1]),$_[1]) if (@_ == 2) && ($_[0]||0 == 1) && ref($_[1]);
2293 my $count = abs(shift || 0);
2295 my (@a,$k,$d); # resulting array, temp, and downgrade
2298 # okay, got object as first
2303 # nope, got 1,2 (Class->xxx(1) => Class,1 and not supported)
2305 $a[0] = shift if $_[0] =~ /^[A-Z].*::/; # classname as first?
2309 # disable downgrading, because Math::BigFLoat->foo('1.0','2.0') needs floats
2310 if (defined ${"$a[0]::downgrade"})
2312 $d = ${"$a[0]::downgrade"};
2313 ${"$a[0]::downgrade"} = undef;
2316 my $up = ${"$a[0]::upgrade"};
2317 #print "Now in objectify, my class is today $a[0], count = $count\n";
2325 $k = $a[0]->new($k);
2327 elsif (!defined $up && ref($k) ne $a[0])
2329 # foreign object, try to convert to integer
2330 $k->can('as_number') ? $k = $k->as_number() : $k = $a[0]->new($k);
2343 $k = $a[0]->new($k);
2345 elsif (!defined $up && ref($k) ne $a[0])
2347 # foreign object, try to convert to integer
2348 $k->can('as_number') ? $k = $k->as_number() : $k = $a[0]->new($k);
2352 push @a,@_; # return other params, too
2356 require Carp; Carp::croak ("$class objectify needs list context");
2358 ${"$a[0]::downgrade"} = $d;
2366 $IMPORT++; # remember we did import()
2367 my @a; my $l = scalar @_;
2368 for ( my $i = 0; $i < $l ; $i++ )
2370 if ($_[$i] eq ':constant')
2372 # this causes overlord er load to step in
2374 integer => sub { $self->new(shift) },
2375 binary => sub { $self->new(shift) };
2377 elsif ($_[$i] eq 'upgrade')
2379 # this causes upgrading
2380 $upgrade = $_[$i+1]; # or undef to disable
2383 elsif ($_[$i] =~ /^lib$/i)
2385 # this causes a different low lib to take care...
2386 $CALC = $_[$i+1] || '';
2394 # any non :constant stuff is handled by our parent, Exporter
2395 # even if @_ is empty, to give it a chance
2396 $self->SUPER::import(@a); # need it for subclasses
2397 $self->export_to_level(1,$self,@a); # need it for MBF
2399 # try to load core math lib
2400 my @c = split /\s*,\s*/,$CALC;
2401 push @c,'Calc'; # if all fail, try this
2402 $CALC = ''; # signal error
2403 foreach my $lib (@c)
2405 next if ($lib || '') eq '';
2406 $lib = 'Math::BigInt::'.$lib if $lib !~ /^Math::BigInt/i;
2410 # Perl < 5.6.0 dies with "out of memory!" when eval() and ':constant' is
2411 # used in the same script, or eval inside import().
2412 my @parts = split /::/, $lib; # Math::BigInt => Math BigInt
2413 my $file = pop @parts; $file .= '.pm'; # BigInt => BigInt.pm
2415 $file = File::Spec->catfile (@parts, $file);
2416 eval { require "$file"; $lib->import( @c ); }
2420 eval "use $lib qw/@c/;";
2425 # loaded it ok, see if the api_version() is high enough
2426 if ($lib->can('api_version') && $lib->api_version() >= 1.0)
2429 # api_version matches, check if it really provides anything we need
2433 add mul div sub dec inc
2434 acmp len digit is_one is_zero is_even is_odd
2436 new copy check from_hex from_bin as_hex as_bin zeros
2437 rsft lsft xor and or
2438 mod sqrt root fac pow modinv modpow log_int gcd
2441 if (!$lib->can("_$method"))
2443 if (($WARN{$lib}||0) < 2)
2446 Carp::carp ("$lib is missing method '_$method'");
2447 $WARN{$lib} = 1; # still warn about the lib
2456 last; # found a usable one, break
2460 if (($WARN{$lib}||0) < 2)
2462 my $ver = eval "\$$lib\::VERSION";
2464 Carp::carp ("Cannot load outdated $lib v$ver, please upgrade");
2465 $WARN{$lib} = 2; # never warn again
2473 Carp::croak ("Couldn't load any math lib, not even 'Calc.pm'");
2475 _fill_can_cache(); # for emulating lower math lib functions
2480 # fill $CAN with the results of $CALC->can(...)
2483 for my $method (qw/ signed_and or signed_or xor signed_xor /)
2485 $CAN{$method} = $CALC->can("_$method") ? 1 : 0;
2491 # convert a (ref to) big hex string to BigInt, return undef for error
2494 my $x = Math::BigInt->bzero();
2497 $hs =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
2498 $hs =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
2500 return $x->bnan() if $hs !~ /^[\-\+]?0x[0-9A-Fa-f]+$/;
2502 my $sign = '+'; $sign = '-' if $hs =~ /^-/;
2504 $hs =~ s/^[+-]//; # strip sign
2505 $x->{value} = $CALC->_from_hex($hs);
2506 $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
2512 # convert a (ref to) big binary string to BigInt, return undef for error
2515 my $x = Math::BigInt->bzero();
2517 $bs =~ s/([01])_([01])/$1$2/g;
2518 $bs =~ s/([01])_([01])/$1$2/g;
2519 return $x->bnan() if $bs !~ /^[+-]?0b[01]+$/;
2521 my $sign = '+'; $sign = '-' if $bs =~ /^\-/;
2522 $bs =~ s/^[+-]//; # strip sign
2524 $x->{value} = $CALC->_from_bin($bs);
2525 $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
2531 # (ref to num_str) return num_str
2532 # internal, take apart a string and return the pieces
2533 # strip leading/trailing whitespace, leading zeros, underscore and reject
2537 # strip white space at front, also extranous leading zeros
2538 $x =~ s/^\s*([-]?)0*([0-9])/$1$2/g; # will not strip ' .2'
2539 $x =~ s/^\s+//; # but this will
2540 $x =~ s/\s+$//g; # strip white space at end
2542 # shortcut, if nothing to split, return early
2543 if ($x =~ /^[+-]?\d+\z/)
2545 $x =~ s/^([+-])0*([0-9])/$2/; my $sign = $1 || '+';
2546 return (\$sign, \$x, \'', \'', \0);
2549 # invalid starting char?
2550 return if $x !~ /^[+-]?(\.?[0-9]|0b[0-1]|0x[0-9a-fA-F])/;
2552 return __from_hex($x) if $x =~ /^[\-\+]?0x/; # hex string
2553 return __from_bin($x) if $x =~ /^[\-\+]?0b/; # binary string
2555 # strip underscores between digits
2556 $x =~ s/(\d)_(\d)/$1$2/g;
2557 $x =~ s/(\d)_(\d)/$1$2/g; # do twice for 1_2_3
2559 # some possible inputs:
2560 # 2.1234 # 0.12 # 1 # 1E1 # 2.134E1 # 434E-10 # 1.02009E-2
2561 # .2 # 1_2_3.4_5_6 # 1.4E1_2_3 # 1e3 # +.2 # 0e999
2563 my ($m,$e,$last) = split /[Ee]/,$x;
2564 return if defined $last; # last defined => 1e2E3 or others
2565 $e = '0' if !defined $e || $e eq "";
2567 # sign,value for exponent,mantint,mantfrac
2568 my ($es,$ev,$mis,$miv,$mfv);
2570 if ($e =~ /^([+-]?)0*(\d+)$/) # strip leading zeros
2574 return if $m eq '.' || $m eq '';
2575 my ($mi,$mf,$lastf) = split /\./,$m;
2576 return if defined $lastf; # lastf defined => 1.2.3 or others
2577 $mi = '0' if !defined $mi;
2578 $mi .= '0' if $mi =~ /^[\-\+]?$/;
2579 $mf = '0' if !defined $mf || $mf eq '';
2580 if ($mi =~ /^([+-]?)0*(\d+)$/) # strip leading zeros
2582 $mis = $1||'+'; $miv = $2;
2583 return unless ($mf =~ /^(\d*?)0*$/); # strip trailing zeros
2585 # handle the 0e999 case here
2586 $ev = 0 if $miv eq '0' && $mfv eq '';
2587 return (\$mis,\$miv,\$mfv,\$es,\$ev);
2590 return; # NaN, not a number
2593 ##############################################################################
2594 # internal calculation routines (others are in Math::BigInt::Calc etc)
2598 # (BINT or num_str, BINT or num_str) return BINT
2599 # does modify first argument
2602 my $x = shift; my $ty = shift;
2603 return $x->bnan() if ($x->{sign} eq $nan) || ($ty->{sign} eq $nan);
2604 $x * $ty / bgcd($x,$ty);
2607 ###############################################################################
2608 # this method return 0 if the object can be modified, or 1 for not
2609 # We use a fast constant sub() here, to avoid costly calls. Subclasses
2610 # may override it with special code (f.i. Math::BigInt::Constant does so)
2612 sub modify () { 0; }
2619 Math::BigInt - Arbitrary size integer math package
2625 # or make it faster: install (optional) Math::BigInt::GMP
2626 # and always use (it will fall back to pure Perl if the
2627 # GMP library is not installed):
2629 use Math::BigInt lib => 'GMP';
2631 my $str = '1234567890';
2632 my @values = (64,74,18);
2633 my $n = 1; my $sign = '-';
2636 $x = Math::BigInt->new($str); # defaults to 0
2637 $y = $x->copy(); # make a true copy
2638 $nan = Math::BigInt->bnan(); # create a NotANumber
2639 $zero = Math::BigInt->bzero(); # create a +0
2640 $inf = Math::BigInt->binf(); # create a +inf
2641 $inf = Math::BigInt->binf('-'); # create a -inf
2642 $one = Math::BigInt->bone(); # create a +1
2643 $one = Math::BigInt->bone('-'); # create a -1
2645 # Testing (don't modify their arguments)
2646 # (return true if the condition is met, otherwise false)
2648 $x->is_zero(); # if $x is +0
2649 $x->is_nan(); # if $x is NaN
2650 $x->is_one(); # if $x is +1
2651 $x->is_one('-'); # if $x is -1
2652 $x->is_odd(); # if $x is odd
2653 $x->is_even(); # if $x is even
2654 $x->is_pos(); # if $x >= 0
2655 $x->is_neg(); # if $x < 0
2656 $x->is_inf($sign); # if $x is +inf, or -inf (sign is default '+')
2657 $x->is_int(); # if $x is an integer (not a float)
2659 # comparing and digit/sign extration
2660 $x->bcmp($y); # compare numbers (undef,<0,=0,>0)
2661 $x->bacmp($y); # compare absolutely (undef,<0,=0,>0)
2662 $x->sign(); # return the sign, either +,- or NaN
2663 $x->digit($n); # return the nth digit, counting from right
2664 $x->digit(-$n); # return the nth digit, counting from left
2666 # The following all modify their first argument. If you want to preserve
2667 # $x, use $z = $x->copy()->bXXX($y); See under L<CAVEATS> for why this is
2668 # neccessary when mixing $a = $b assigments with non-overloaded math.
2670 $x->bzero(); # set $x to 0
2671 $x->bnan(); # set $x to NaN
2672 $x->bone(); # set $x to +1
2673 $x->bone('-'); # set $x to -1
2674 $x->binf(); # set $x to inf
2675 $x->binf('-'); # set $x to -inf
2677 $x->bneg(); # negation
2678 $x->babs(); # absolute value
2679 $x->bnorm(); # normalize (no-op in BigInt)
2680 $x->bnot(); # two's complement (bit wise not)
2681 $x->binc(); # increment $x by 1
2682 $x->bdec(); # decrement $x by 1
2684 $x->badd($y); # addition (add $y to $x)
2685 $x->bsub($y); # subtraction (subtract $y from $x)
2686 $x->bmul($y); # multiplication (multiply $x by $y)
2687 $x->bdiv($y); # divide, set $x to quotient
2688 # return (quo,rem) or quo if scalar
2690 $x->bmod($y); # modulus (x % y)
2691 $x->bmodpow($exp,$mod); # modular exponentation (($num**$exp) % $mod))
2692 $x->bmodinv($mod); # the inverse of $x in the given modulus $mod
2694 $x->bpow($y); # power of arguments (x ** y)
2695 $x->blsft($y); # left shift
2696 $x->brsft($y); # right shift
2697 $x->blsft($y,$n); # left shift, by base $n (like 10)
2698 $x->brsft($y,$n); # right shift, by base $n (like 10)
2700 $x->band($y); # bitwise and
2701 $x->bior($y); # bitwise inclusive or
2702 $x->bxor($y); # bitwise exclusive or
2703 $x->bnot(); # bitwise not (two's complement)
2705 $x->bsqrt(); # calculate square-root
2706 $x->broot($y); # $y'th root of $x (e.g. $y == 3 => cubic root)
2707 $x->bfac(); # factorial of $x (1*2*3*4*..$x)
2709 $x->round($A,$P,$mode); # round to accuracy or precision using mode $mode
2710 $x->bround($n); # accuracy: preserve $n digits
2711 $x->bfround($n); # round to $nth digit, no-op for BigInts
2713 # The following do not modify their arguments in BigInt (are no-ops),
2714 # but do so in BigFloat:
2716 $x->bfloor(); # return integer less or equal than $x
2717 $x->bceil(); # return integer greater or equal than $x
2719 # The following do not modify their arguments:
2721 # greatest common divisor (no OO style)
2722 my $gcd = Math::BigInt::bgcd(@values);
2723 # lowest common multiplicator (no OO style)
2724 my $lcm = Math::BigInt::blcm(@values);
2726 $x->length(); # return number of digits in number
2727 ($xl,$f) = $x->length(); # length of number and length of fraction part,
2728 # latter is always 0 digits long for BigInt's
2730 $x->exponent(); # return exponent as BigInt
2731 $x->mantissa(); # return (signed) mantissa as BigInt
2732 $x->parts(); # return (mantissa,exponent) as BigInt
2733 $x->copy(); # make a true copy of $x (unlike $y = $x;)
2734 $x->as_int(); # return as BigInt (in BigInt: same as copy())
2735 $x->numify(); # return as scalar (might overflow!)
2737 # conversation to string (do not modify their argument)
2738 $x->bstr(); # normalized string
2739 $x->bsstr(); # normalized string in scientific notation
2740 $x->as_hex(); # as signed hexadecimal string with prefixed 0x
2741 $x->as_bin(); # as signed binary string with prefixed 0b
2744 # precision and accuracy (see section about rounding for more)
2745 $x->precision(); # return P of $x (or global, if P of $x undef)
2746 $x->precision($n); # set P of $x to $n
2747 $x->accuracy(); # return A of $x (or global, if A of $x undef)
2748 $x->accuracy($n); # set A $x to $n
2751 Math::BigInt->precision(); # get/set global P for all BigInt objects
2752 Math::BigInt->accuracy(); # get/set global A for all BigInt objects
2753 Math::BigInt->config(); # return hash containing configuration
2757 All operators (inlcuding basic math operations) are overloaded if you
2758 declare your big integers as
2760 $i = new Math::BigInt '123_456_789_123_456_789';
2762 Operations with overloaded operators preserve the arguments which is
2763 exactly what you expect.
2769 Input values to these routines may be any string, that looks like a number
2770 and results in an integer, including hexadecimal and binary numbers.
2772 Scalars holding numbers may also be passed, but note that non-integer numbers
2773 may already have lost precision due to the conversation to float. Quote
2774 your input if you want BigInt to see all the digits:
2776 $x = Math::BigInt->new(12345678890123456789); # bad
2777 $x = Math::BigInt->new('12345678901234567890'); # good
2779 You can include one underscore between any two digits.
2781 This means integer values like 1.01E2 or even 1000E-2 are also accepted.
2782 Non-integer values result in NaN.
2784 Currently, Math::BigInt::new() defaults to 0, while Math::BigInt::new('')
2785 results in 'NaN'. This might change in the future, so use always the following
2786 explicit forms to get a zero or NaN:
2788 $zero = Math::BigInt->bzero();
2789 $nan = Math::BigInt->bnan();
2791 C<bnorm()> on a BigInt object is now effectively a no-op, since the numbers
2792 are always stored in normalized form. If passed a string, creates a BigInt
2793 object from the input.
2797 Output values are BigInt objects (normalized), except for bstr(), which
2798 returns a string in normalized form.
2799 Some routines (C<is_odd()>, C<is_even()>, C<is_zero()>, C<is_one()>,
2800 C<is_nan()>) return true or false, while others (C<bcmp()>, C<bacmp()>)
2801 return either undef, <0, 0 or >0 and are suited for sort.
2807 Each of the methods below (except config(), accuracy() and precision())
2808 accepts three additional parameters. These arguments $A, $P and $R are
2809 accuracy, precision and round_mode. Please see the section about
2810 L<ACCURACY and PRECISION> for more information.
2816 print Dumper ( Math::BigInt->config() );
2817 print Math::BigInt->config()->{lib},"\n";
2819 Returns a hash containing the configuration, e.g. the version number, lib
2820 loaded etc. The following hash keys are currently filled in with the
2821 appropriate information.
2825 ============================================================
2826 lib Name of the low-level math library
2828 lib_version Version of low-level math library (see 'lib')
2830 class The class name of config() you just called
2832 upgrade To which class math operations might be upgraded
2834 downgrade To which class math operations might be downgraded
2836 precision Global precision
2838 accuracy Global accuracy
2840 round_mode Global round mode
2842 version version number of the class you used
2844 div_scale Fallback acccuracy for div
2846 trap_nan If true, traps creation of NaN via croak()
2848 trap_inf If true, traps creation of +inf/-inf via croak()
2851 The following values can be set by passing C<config()> a reference to a hash:
2854 upgrade downgrade precision accuracy round_mode div_scale
2858 $new_cfg = Math::BigInt->config( { trap_inf => 1, precision => 5 } );
2862 $x->accuracy(5); # local for $x
2863 CLASS->accuracy(5); # global for all members of CLASS
2864 $A = $x->accuracy(); # read out
2865 $A = CLASS->accuracy(); # read out
2867 Set or get the global or local accuracy, aka how many significant digits the
2870 Please see the section about L<ACCURACY AND PRECISION> for further details.
2872 Value must be greater than zero. Pass an undef value to disable it:
2874 $x->accuracy(undef);
2875 Math::BigInt->accuracy(undef);
2877 Returns the current accuracy. For C<$x->accuracy()> it will return either the
2878 local accuracy, or if not defined, the global. This means the return value
2879 represents the accuracy that will be in effect for $x:
2881 $y = Math::BigInt->new(1234567); # unrounded
2882 print Math::BigInt->accuracy(4),"\n"; # set 4, print 4
2883 $x = Math::BigInt->new(123456); # will be automatically rounded
2884 print "$x $y\n"; # '123500 1234567'
2885 print $x->accuracy(),"\n"; # will be 4
2886 print $y->accuracy(),"\n"; # also 4, since global is 4
2887 print Math::BigInt->accuracy(5),"\n"; # set to 5, print 5
2888 print $x->accuracy(),"\n"; # still 4
2889 print $y->accuracy(),"\n"; # 5, since global is 5
2891 Note: Works also for subclasses like Math::BigFloat. Each class has it's own
2892 globals separated from Math::BigInt, but it is possible to subclass
2893 Math::BigInt and make the globals of the subclass aliases to the ones from
2898 $x->precision(-2); # local for $x, round right of the dot
2899 $x->precision(2); # ditto, but round left of the dot
2900 CLASS->accuracy(5); # global for all members of CLASS
2901 CLASS->precision(-5); # ditto
2902 $P = CLASS->precision(); # read out
2903 $P = $x->precision(); # read out
2905 Set or get the global or local precision, aka how many digits the result has
2906 after the dot (or where to round it when passing a positive number). In
2907 Math::BigInt, passing a negative number precision has no effect since no
2908 numbers have digits after the dot.
2910 Please see the section about L<ACCURACY AND PRECISION> for further details.
2912 Value must be greater than zero. Pass an undef value to disable it:
2914 $x->precision(undef);
2915 Math::BigInt->precision(undef);
2917 Returns the current precision. For C<$x->precision()> it will return either the
2918 local precision of $x, or if not defined, the global. This means the return
2919 value represents the accuracy that will be in effect for $x:
2921 $y = Math::BigInt->new(1234567); # unrounded
2922 print Math::BigInt->precision(4),"\n"; # set 4, print 4
2923 $x = Math::BigInt->new(123456); # will be automatically rounded
2925 Note: Works also for subclasses like Math::BigFloat. Each class has it's own
2926 globals separated from Math::BigInt, but it is possible to subclass
2927 Math::BigInt and make the globals of the subclass aliases to the ones from
2934 Shifts $x right by $y in base $n. Default is base 2, used are usually 10 and
2935 2, but others work, too.
2937 Right shifting usually amounts to dividing $x by $n ** $y and truncating the
2941 $x = Math::BigInt->new(10);
2942 $x->brsft(1); # same as $x >> 1: 5
2943 $x = Math::BigInt->new(1234);
2944 $x->brsft(2,10); # result 12
2946 There is one exception, and that is base 2 with negative $x:
2949 $x = Math::BigInt->new(-5);
2952 This will print -3, not -2 (as it would if you divide -5 by 2 and truncate the
2957 $x = Math::BigInt->new($str,$A,$P,$R);
2959 Creates a new BigInt object from a scalar or another BigInt object. The
2960 input is accepted as decimal, hex (with leading '0x') or binary (with leading
2963 See L<Input> for more info on accepted input formats.
2967 $x = Math::BigInt->bnan();
2969 Creates a new BigInt object representing NaN (Not A Number).
2970 If used on an object, it will set it to NaN:
2976 $x = Math::BigInt->bzero();
2978 Creates a new BigInt object representing zero.
2979 If used on an object, it will set it to zero:
2985 $x = Math::BigInt->binf($sign);
2987 Creates a new BigInt object representing infinity. The optional argument is
2988 either '-' or '+', indicating whether you want infinity or minus infinity.
2989 If used on an object, it will set it to infinity:
2996 $x = Math::BigInt->binf($sign);
2998 Creates a new BigInt object representing one. The optional argument is
2999 either '-' or '+', indicating whether you want one or minus one.
3000 If used on an object, it will set it to one:
3005 =head2 is_one()/is_zero()/is_nan()/is_inf()
3008 $x->is_zero(); # true if arg is +0
3009 $x->is_nan(); # true if arg is NaN
3010 $x->is_one(); # true if arg is +1
3011 $x->is_one('-'); # true if arg is -1
3012 $x->is_inf(); # true if +inf
3013 $x->is_inf('-'); # true if -inf (sign is default '+')
3015 These methods all test the BigInt for beeing one specific value and return
3016 true or false depending on the input. These are faster than doing something
3021 =head2 is_pos()/is_neg()
3023 $x->is_pos(); # true if >= 0
3024 $x->is_neg(); # true if < 0
3026 The methods return true if the argument is positive or negative, respectively.
3027 C<NaN> is neither positive nor negative, while C<+inf> counts as positive, and
3028 C<-inf> is negative. A C<zero> is positive.
3030 These methods are only testing the sign, and not the value.
3032 C<is_positive()> and C<is_negative()> are aliase to C<is_pos()> and
3033 C<is_neg()>, respectively. C<is_positive()> and C<is_negative()> were
3034 introduced in v1.36, while C<is_pos()> and C<is_neg()> were only introduced
3037 =head2 is_odd()/is_even()/is_int()
3039 $x->is_odd(); # true if odd, false for even
3040 $x->is_even(); # true if even, false for odd
3041 $x->is_int(); # true if $x is an integer
3043 The return true when the argument satisfies the condition. C<NaN>, C<+inf>,
3044 C<-inf> are not integers and are neither odd nor even.
3046 In BigInt, all numbers except C<NaN>, C<+inf> and C<-inf> are integers.
3052 Compares $x with $y and takes the sign into account.
3053 Returns -1, 0, 1 or undef.
3059 Compares $x with $y while ignoring their. Returns -1, 0, 1 or undef.
3065 Return the sign, of $x, meaning either C<+>, C<->, C<-inf>, C<+inf> or NaN.
3069 $x->digit($n); # return the nth digit, counting from right
3071 If C<$n> is negative, returns the digit counting from left.
3077 Negate the number, e.g. change the sign between '+' and '-', or between '+inf'
3078 and '-inf', respectively. Does nothing for NaN or zero.
3084 Set the number to it's absolute value, e.g. change the sign from '-' to '+'
3085 and from '-inf' to '+inf', respectively. Does nothing for NaN or positive
3090 $x->bnorm(); # normalize (no-op)
3096 Two's complement (bit wise not). This is equivalent to
3104 $x->binc(); # increment x by 1
3108 $x->bdec(); # decrement x by 1
3112 $x->badd($y); # addition (add $y to $x)
3116 $x->bsub($y); # subtraction (subtract $y from $x)
3120 $x->bmul($y); # multiplication (multiply $x by $y)
3124 $x->bdiv($y); # divide, set $x to quotient
3125 # return (quo,rem) or quo if scalar
3129 $x->bmod($y); # modulus (x % y)
3133 num->bmodinv($mod); # modular inverse
3135 Returns the inverse of C<$num> in the given modulus C<$mod>. 'C<NaN>' is
3136 returned unless C<$num> is relatively prime to C<$mod>, i.e. unless
3137 C<bgcd($num, $mod)==1>.
3141 $num->bmodpow($exp,$mod); # modular exponentation
3142 # ($num**$exp % $mod)
3144 Returns the value of C<$num> taken to the power C<$exp> in the modulus
3145 C<$mod> using binary exponentation. C<bmodpow> is far superior to
3150 because it is much faster - it reduces internal variables into
3151 the modulus whenever possible, so it operates on smaller numbers.
3153 C<bmodpow> also supports negative exponents.
3155 bmodpow($num, -1, $mod)
3157 is exactly equivalent to
3163 $x->bpow($y); # power of arguments (x ** y)
3167 $x->blsft($y); # left shift
3168 $x->blsft($y,$n); # left shift, in base $n (like 10)
3172 $x->brsft($y); # right shift
3173 $x->brsft($y,$n); # right shift, in base $n (like 10)
3177 $x->band($y); # bitwise and
3181 $x->bior($y); # bitwise inclusive or
3185 $x->bxor($y); # bitwise exclusive or
3189 $x->bnot(); # bitwise not (two's complement)
3193 $x->bsqrt(); # calculate square-root
3197 $x->bfac(); # factorial of $x (1*2*3*4*..$x)
3201 $x->round($A,$P,$round_mode);
3203 Round $x to accuracy C<$A> or precision C<$P> using the round mode
3208 $x->bround($N); # accuracy: preserve $N digits
3212 $x->bfround($N); # round to $Nth digit, no-op for BigInts
3218 Set $x to the integer less or equal than $x. This is a no-op in BigInt, but
3219 does change $x in BigFloat.
3225 Set $x to the integer greater or equal than $x. This is a no-op in BigInt, but
3226 does change $x in BigFloat.
3230 bgcd(@values); # greatest common divisor (no OO style)
3234 blcm(@values); # lowest common multiplicator (no OO style)
3239 ($xl,$fl) = $x->length();
3241 Returns the number of digits in the decimal representation of the number.
3242 In list context, returns the length of the integer and fraction part. For
3243 BigInt's, the length of the fraction part will always be 0.
3249 Return the exponent of $x as BigInt.
3255 Return the signed mantissa of $x as BigInt.
3259 $x->parts(); # return (mantissa,exponent) as BigInt
3263 $x->copy(); # make a true copy of $x (unlike $y = $x;)
3269 Returns $x as a BigInt (truncated towards zero). In BigInt this is the same as
3272 C<as_number()> is an alias to this method. C<as_number> was introduced in
3273 v1.22, while C<as_int()> was only introduced in v1.68.
3279 Returns a normalized string represantation of C<$x>.
3283 $x->bsstr(); # normalized string in scientific notation
3287 $x->as_hex(); # as signed hexadecimal string with prefixed 0x
3291 $x->as_bin(); # as signed binary string with prefixed 0b
3293 =head1 ACCURACY and PRECISION
3295 Since version v1.33, Math::BigInt and Math::BigFloat have full support for
3296 accuracy and precision based rounding, both automatically after every
3297 operation, as well as manually.
3299 This section describes the accuracy/precision handling in Math::Big* as it
3300 used to be and as it is now, complete with an explanation of all terms and
3303 Not yet implemented things (but with correct description) are marked with '!',
3304 things that need to be answered are marked with '?'.
3306 In the next paragraph follows a short description of terms used here (because
3307 these may differ from terms used by others people or documentation).
3309 During the rest of this document, the shortcuts A (for accuracy), P (for
3310 precision), F (fallback) and R (rounding mode) will be used.
3314 A fixed number of digits before (positive) or after (negative)
3315 the decimal point. For example, 123.45 has a precision of -2. 0 means an
3316 integer like 123 (or 120). A precision of 2 means two digits to the left
3317 of the decimal point are zero, so 123 with P = 1 becomes 120. Note that
3318 numbers with zeros before the decimal point may have different precisions,
3319 because 1200 can have p = 0, 1 or 2 (depending on what the inital value
3320 was). It could also have p < 0, when the digits after the decimal point
3323 The string output (of floating point numbers) will be padded with zeros:
3325 Initial value P A Result String
3326 ------------------------------------------------------------
3327 1234.01 -3 1000 1000
3330 1234.001 1 1234 1234.0
3332 1234.01 2 1234.01 1234.01
3333 1234.01 5 1234.01 1234.01000
3335 For BigInts, no padding occurs.
3339 Number of significant digits. Leading zeros are not counted. A
3340 number may have an accuracy greater than the non-zero digits
3341 when there are zeros in it or trailing zeros. For example, 123.456 has
3342 A of 6, 10203 has 5, 123.0506 has 7, 123.450000 has 8 and 0.000123 has 3.
3344 The string output (of floating point numbers) will be padded with zeros:
3346 Initial value P A Result String
3347 ------------------------------------------------------------
3349 1234.01 6 1234.01 1234.01
3350 1234.1 8 1234.1 1234.1000
3352 For BigInts, no padding occurs.
3356 When both A and P are undefined, this is used as a fallback accuracy when
3359 =head2 Rounding mode R
3361 When rounding a number, different 'styles' or 'kinds'
3362 of rounding are possible. (Note that random rounding, as in
3363 Math::Round, is not implemented.)
3369 truncation invariably removes all digits following the
3370 rounding place, replacing them with zeros. Thus, 987.65 rounded
3371 to tens (P=1) becomes 980, and rounded to the fourth sigdig
3372 becomes 987.6 (A=4). 123.456 rounded to the second place after the
3373 decimal point (P=-2) becomes 123.46.
3375 All other implemented styles of rounding attempt to round to the
3376 "nearest digit." If the digit D immediately to the right of the
3377 rounding place (skipping the decimal point) is greater than 5, the
3378 number is incremented at the rounding place (possibly causing a
3379 cascade of incrementation): e.g. when rounding to units, 0.9 rounds
3380 to 1, and -19.9 rounds to -20. If D < 5, the number is similarly
3381 truncated at the rounding place: e.g. when rounding to units, 0.4
3382 rounds to 0, and -19.4 rounds to -19.
3384 However the results of other styles of rounding differ if the
3385 digit immediately to the right of the rounding place (skipping the
3386 decimal point) is 5 and if there are no digits, or no digits other
3387 than 0, after that 5. In such cases:
3391 rounds the digit at the rounding place to 0, 2, 4, 6, or 8
3392 if it is not already. E.g., when rounding to the first sigdig, 0.45
3393 becomes 0.4, -0.55 becomes -0.6, but 0.4501 becomes 0.5.
3397 rounds the digit at the rounding place to 1, 3, 5, 7, or 9 if
3398 it is not already. E.g., when rounding to the first sigdig, 0.45
3399 becomes 0.5, -0.55 becomes -0.5, but 0.5501 becomes 0.6.
3403 round to plus infinity, i.e. always round up. E.g., when
3404 rounding to the first sigdig, 0.45 becomes 0.5, -0.55 becomes -0.5,
3405 and 0.4501 also becomes 0.5.
3409 round to minus infinity, i.e. always round down. E.g., when
3410 rounding to the first sigdig, 0.45 becomes 0.4, -0.55 becomes -0.6,
3411 but 0.4501 becomes 0.5.
3415 round to zero, i.e. positive numbers down, negative ones up.
3416 E.g., when rounding to the first sigdig, 0.45 becomes 0.4, -0.55
3417 becomes -0.5, but 0.4501 becomes 0.5.
3421 The handling of A & P in MBI/MBF (the old core code shipped with Perl
3422 versions <= 5.7.2) is like this:
3428 * ffround($p) is able to round to $p number of digits after the decimal
3430 * otherwise P is unused
3432 =item Accuracy (significant digits)
3434 * fround($a) rounds to $a significant digits
3435 * only fdiv() and fsqrt() take A as (optional) paramater
3436 + other operations simply create the same number (fneg etc), or more (fmul)
3438 + rounding/truncating is only done when explicitly calling one of fround
3439 or ffround, and never for BigInt (not implemented)
3440 * fsqrt() simply hands its accuracy argument over to fdiv.
3441 * the documentation and the comment in the code indicate two different ways
3442 on how fdiv() determines the maximum number of digits it should calculate,
3443 and the actual code does yet another thing
3445 max($Math::BigFloat::div_scale,length(dividend)+length(divisor))
3447 result has at most max(scale, length(dividend), length(divisor)) digits
3449 scale = max(scale, length(dividend)-1,length(divisor)-1);
3450 scale += length(divisior) - length(dividend);
3451 So for lx = 3, ly = 9, scale = 10, scale will actually be 16 (10+9-3).
3452 Actually, the 'difference' added to the scale is calculated from the
3453 number of "significant digits" in dividend and divisor, which is derived
3454 by looking at the length of the mantissa. Which is wrong, since it includes
3455 the + sign (oops) and actually gets 2 for '+100' and 4 for '+101'. Oops
3456 again. Thus 124/3 with div_scale=1 will get you '41.3' based on the strange
3457 assumption that 124 has 3 significant digits, while 120/7 will get you
3458 '17', not '17.1' since 120 is thought to have 2 significant digits.
3459 The rounding after the division then uses the remainder and $y to determine
3460 wether it must round up or down.
3461 ? I have no idea which is the right way. That's why I used a slightly more
3462 ? simple scheme and tweaked the few failing testcases to match it.
3466 This is how it works now:
3470 =item Setting/Accessing
3472 * You can set the A global via C<< Math::BigInt->accuracy() >> or
3473 C<< Math::BigFloat->accuracy() >> or whatever class you are using.
3474 * You can also set P globally by using C<< Math::SomeClass->precision() >>
3476 * Globals are classwide, and not inherited by subclasses.
3477 * to undefine A, use C<< Math::SomeCLass->accuracy(undef); >>
3478 * to undefine P, use C<< Math::SomeClass->precision(undef); >>
3479 * Setting C<< Math::SomeClass->accuracy() >> clears automatically
3480 C<< Math::SomeClass->precision() >>, and vice versa.
3481 * To be valid, A must be > 0, P can have any value.
3482 * If P is negative, this means round to the P'th place to the right of the
3483 decimal point; positive values mean to the left of the decimal point.
3484 P of 0 means round to integer.
3485 * to find out the current global A, use C<< Math::SomeClass->accuracy() >>
3486 * to find out the current global P, use C<< Math::SomeClass->precision() >>
3487 * use C<< $x->accuracy() >> respective C<< $x->precision() >> for the local
3488 setting of C<< $x >>.
3489 * Please note that C<< $x->accuracy() >> respecive C<< $x->precision() >>
3490 return eventually defined global A or P, when C<< $x >>'s A or P is not
3493 =item Creating numbers
3495 * When you create a number, you can give it's desired A or P via:
3496 $x = Math::BigInt->new($number,$A,$P);
3497 * Only one of A or P can be defined, otherwise the result is NaN
3498 * If no A or P is give ($x = Math::BigInt->new($number) form), then the
3499 globals (if set) will be used. Thus changing the global defaults later on
3500 will not change the A or P of previously created numbers (i.e., A and P of
3501 $x will be what was in effect when $x was created)
3502 * If given undef for A and P, B<no> rounding will occur, and the globals will
3503 B<not> be used. This is used by subclasses to create numbers without
3504 suffering rounding in the parent. Thus a subclass is able to have it's own
3505 globals enforced upon creation of a number by using
3506 C<< $x = Math::BigInt->new($number,undef,undef) >>:
3508 use Math::BigInt::SomeSubclass;
3511 Math::BigInt->accuracy(2);
3512 Math::BigInt::SomeSubClass->accuracy(3);
3513 $x = Math::BigInt::SomeSubClass->new(1234);
3515 $x is now 1230, and not 1200. A subclass might choose to implement
3516 this otherwise, e.g. falling back to the parent's A and P.
3520 * If A or P are enabled/defined, they are used to round the result of each
3521 operation according to the rules below
3522 * Negative P is ignored in Math::BigInt, since BigInts never have digits
3523 after the decimal point
3524 * Math::BigFloat uses Math::BigInt internally, but setting A or P inside
3525 Math::BigInt as globals does not tamper with the parts of a BigFloat.
3526 A flag is used to mark all Math::BigFloat numbers as 'never round'.
3530 * It only makes sense that a number has only one of A or P at a time.
3531 If you set either A or P on one object, or globally, the other one will
3532 be automatically cleared.
3533 * If two objects are involved in an operation, and one of them has A in
3534 effect, and the other P, this results in an error (NaN).
3535 * A takes precendence over P (Hint: A comes before P).
3536 If neither of them is defined, nothing is used, i.e. the result will have
3537 as many digits as it can (with an exception for fdiv/fsqrt) and will not
3539 * There is another setting for fdiv() (and thus for fsqrt()). If neither of
3540 A or P is defined, fdiv() will use a fallback (F) of $div_scale digits.
3541 If either the dividend's or the divisor's mantissa has more digits than
3542 the value of F, the higher value will be used instead of F.
3543 This is to limit the digits (A) of the result (just consider what would
3544 happen with unlimited A and P in the case of 1/3 :-)
3545 * fdiv will calculate (at least) 4 more digits than required (determined by
3546 A, P or F), and, if F is not used, round the result
3547 (this will still fail in the case of a result like 0.12345000000001 with A
3548 or P of 5, but this can not be helped - or can it?)
3549 * Thus you can have the math done by on Math::Big* class in two modi:
3550 + never round (this is the default):
3551 This is done by setting A and P to undef. No math operation
3552 will round the result, with fdiv() and fsqrt() as exceptions to guard
3553 against overflows. You must explicitely call bround(), bfround() or
3554 round() (the latter with parameters).
3555 Note: Once you have rounded a number, the settings will 'stick' on it
3556 and 'infect' all other numbers engaged in math operations with it, since
3557 local settings have the highest precedence. So, to get SaferRound[tm],
3558 use a copy() before rounding like this:
3560 $x = Math::BigFloat->new(12.34);
3561 $y = Math::BigFloat->new(98.76);
3562 $z = $x * $y; # 1218.6984
3563 print $x->copy()->fround(3); # 12.3 (but A is now 3!)
3564 $z = $x * $y; # still 1218.6984, without
3565 # copy would have been 1210!
3567 + round after each op:
3568 After each single operation (except for testing like is_zero()), the
3569 method round() is called and the result is rounded appropriately. By
3570 setting proper values for A and P, you can have all-the-same-A or
3571 all-the-same-P modes. For example, Math::Currency might set A to undef,
3572 and P to -2, globally.
3574 ?Maybe an extra option that forbids local A & P settings would be in order,
3575 ?so that intermediate rounding does not 'poison' further math?
3577 =item Overriding globals
3579 * you will be able to give A, P and R as an argument to all the calculation
3580 routines; the second parameter is A, the third one is P, and the fourth is
3581 R (shift right by one for binary operations like badd). P is used only if
3582 the first parameter (A) is undefined. These three parameters override the
3583 globals in the order detailed as follows, i.e. the first defined value
3585 (local: per object, global: global default, parameter: argument to sub)
3588 + local A (if defined on both of the operands: smaller one is taken)
3589 + local P (if defined on both of the operands: bigger one is taken)
3593 * fsqrt() will hand its arguments to fdiv(), as it used to, only now for two
3594 arguments (A and P) instead of one
3596 =item Local settings
3598 * You can set A or P locally by using C<< $x->accuracy() >> or
3599 C<< $x->precision() >>
3600 and thus force different A and P for different objects/numbers.
3601 * Setting A or P this way immediately rounds $x to the new value.
3602 * C<< $x->accuracy() >> clears C<< $x->precision() >>, and vice versa.
3606 * the rounding routines will use the respective global or local settings.
3607 fround()/bround() is for accuracy rounding, while ffround()/bfround()
3609 * the two rounding functions take as the second parameter one of the
3610 following rounding modes (R):
3611 'even', 'odd', '+inf', '-inf', 'zero', 'trunc'
3612 * you can set/get the global R by using C<< Math::SomeClass->round_mode() >>
3613 or by setting C<< $Math::SomeClass::round_mode >>
3614 * after each operation, C<< $result->round() >> is called, and the result may
3615 eventually be rounded (that is, if A or P were set either locally,
3616 globally or as parameter to the operation)
3617 * to manually round a number, call C<< $x->round($A,$P,$round_mode); >>
3618 this will round the number by using the appropriate rounding function
3619 and then normalize it.
3620 * rounding modifies the local settings of the number:
3622 $x = Math::BigFloat->new(123.456);
3626 Here 4 takes precedence over 5, so 123.5 is the result and $x->accuracy()
3627 will be 4 from now on.
3629 =item Default values
3638 * The defaults are set up so that the new code gives the same results as
3639 the old code (except in a few cases on fdiv):
3640 + Both A and P are undefined and thus will not be used for rounding
3641 after each operation.
3642 + round() is thus a no-op, unless given extra parameters A and P
3648 The actual numbers are stored as unsigned big integers (with seperate sign).
3649 You should neither care about nor depend on the internal representation; it
3650 might change without notice. Use only method calls like C<< $x->sign(); >>
3651 instead relying on the internal hash keys like in C<< $x->{sign}; >>.
3655 Math with the numbers is done (by default) by a module called
3656 C<Math::BigInt::Calc>. This is equivalent to saying:
3658 use Math::BigInt lib => 'Calc';
3660 You can change this by using:
3662 use Math::BigInt lib => 'BitVect';
3664 The following would first try to find Math::BigInt::Foo, then
3665 Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
3667 use Math::BigInt lib => 'Foo,Math::BigInt::Bar';
3669 Since Math::BigInt::GMP is in almost all cases faster than Calc (especially in
3670 cases involving really big numbers, where it is B<much> faster), and there is
3671 no penalty if Math::BigInt::GMP is not installed, it is a good idea to always
3674 use Math::BigInt lib => 'GMP';
3676 Different low-level libraries use different formats to store the
3677 numbers. You should not depend on the number having a specific format.
3679 See the respective math library module documentation for further details.
3683 The sign is either '+', '-', 'NaN', '+inf' or '-inf' and stored seperately.
3685 A sign of 'NaN' is used to represent the result when input arguments are not
3686 numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively
3687 minus infinity. You will get '+inf' when dividing a positive number by 0, and
3688 '-inf' when dividing any negative number by 0.
3690 =head2 mantissa(), exponent() and parts()
3692 C<mantissa()> and C<exponent()> return the said parts of the BigInt such
3695 $m = $x->mantissa();
3696 $e = $x->exponent();
3697 $y = $m * ( 10 ** $e );
3698 print "ok\n" if $x == $y;
3700 C<< ($m,$e) = $x->parts() >> is just a shortcut that gives you both of them
3701 in one go. Both the returned mantissa and exponent have a sign.
3703 Currently, for BigInts C<$e> is always 0, except for NaN, +inf and -inf,
3704 where it is C<NaN>; and for C<$x == 0>, where it is C<1> (to be compatible
3705 with Math::BigFloat's internal representation of a zero as C<0E1>).
3707 C<$m> is currently just a copy of the original number. The relation between
3708 C<$e> and C<$m> will stay always the same, though their real values might
3715 sub bint { Math::BigInt->new(shift); }
3717 $x = Math::BigInt->bstr("1234") # string "1234"
3718 $x = "$x"; # same as bstr()
3719 $x = Math::BigInt->bneg("1234"); # BigInt "-1234"
3720 $x = Math::BigInt->babs("-12345"); # BigInt "12345"
3721 $x = Math::BigInt->bnorm("-0 00"); # BigInt "0"
3722 $x = bint(1) + bint(2); # BigInt "3"
3723 $x = bint(1) + "2"; # ditto (auto-BigIntify of "2")
3724 $x = bint(1); # BigInt "1"
3725 $x = $x + 5 / 2; # BigInt "3"
3726 $x = $x ** 3; # BigInt "27"
3727 $x *= 2; # BigInt "54"
3728 $x = Math::BigInt->new(0); # BigInt "0"
3730 $x = Math::BigInt->badd(4,5) # BigInt "9"
3731 print $x->bsstr(); # 9e+0
3733 Examples for rounding:
3738 $x = Math::BigFloat->new(123.4567);
3739 $y = Math::BigFloat->new(123.456789);
3740 Math::BigFloat->accuracy(4); # no more A than 4
3742 ok ($x->copy()->fround(),123.4); # even rounding
3743 print $x->copy()->fround(),"\n"; # 123.4
3744 Math::BigFloat->round_mode('odd'); # round to odd
3745 print $x->copy()->fround(),"\n"; # 123.5
3746 Math::BigFloat->accuracy(5); # no more A than 5
3747 Math::BigFloat->round_mode('odd'); # round to odd
3748 print $x->copy()->fround(),"\n"; # 123.46
3749 $y = $x->copy()->fround(4),"\n"; # A = 4: 123.4
3750 print "$y, ",$y->accuracy(),"\n"; # 123.4, 4
3752 Math::BigFloat->accuracy(undef); # A not important now
3753 Math::BigFloat->precision(2); # P important
3754 print $x->copy()->bnorm(),"\n"; # 123.46
3755 print $x->copy()->fround(),"\n"; # 123.46
3757 Examples for converting:
3759 my $x = Math::BigInt->new('0b1'.'01' x 123);
3760 print "bin: ",$x->as_bin()," hex:",$x->as_hex()," dec: ",$x,"\n";
3762 =head1 Autocreating constants
3764 After C<use Math::BigInt ':constant'> all the B<integer> decimal, hexadecimal
3765 and binary constants in the given scope are converted to C<Math::BigInt>.
3766 This conversion happens at compile time.
3770 perl -MMath::BigInt=:constant -e 'print 2**100,"\n"'
3772 prints the integer value of C<2**100>. Note that without conversion of
3773 constants the expression 2**100 will be calculated as perl scalar.
3775 Please note that strings and floating point constants are not affected,
3778 use Math::BigInt qw/:constant/;
3780 $x = 1234567890123456789012345678901234567890
3781 + 123456789123456789;
3782 $y = '1234567890123456789012345678901234567890'
3783 + '123456789123456789';
3785 do not work. You need an explicit Math::BigInt->new() around one of the
3786 operands. You should also quote large constants to protect loss of precision:
3790 $x = Math::BigInt->new('1234567889123456789123456789123456789');
3792 Without the quotes Perl would convert the large number to a floating point
3793 constant at compile time and then hand the result to BigInt, which results in
3794 an truncated result or a NaN.
3796 This also applies to integers that look like floating point constants:
3798 use Math::BigInt ':constant';
3800 print ref(123e2),"\n";
3801 print ref(123.2e2),"\n";
3803 will print nothing but newlines. Use either L<bignum> or L<Math::BigFloat>
3804 to get this to work.
3808 Using the form $x += $y; etc over $x = $x + $y is faster, since a copy of $x
3809 must be made in the second case. For long numbers, the copy can eat up to 20%
3810 of the work (in the case of addition/subtraction, less for
3811 multiplication/division). If $y is very small compared to $x, the form
3812 $x += $y is MUCH faster than $x = $x + $y since making the copy of $x takes
3813 more time then the actual addition.
3815 With a technique called copy-on-write, the cost of copying with overload could
3816 be minimized or even completely avoided. A test implementation of COW did show
3817 performance gains for overloaded math, but introduced a performance loss due
3818 to a constant overhead for all other operatons. So Math::BigInt does currently
3821 The rewritten version of this module (vs. v0.01) is slower on certain
3822 operations, like C<new()>, C<bstr()> and C<numify()>. The reason are that it
3823 does now more work and handles much more cases. The time spent in these
3824 operations is usually gained in the other math operations so that code on
3825 the average should get (much) faster. If they don't, please contact the author.
3827 Some operations may be slower for small numbers, but are significantly faster
3828 for big numbers. Other operations are now constant (O(1), like C<bneg()>,
3829 C<babs()> etc), instead of O(N) and thus nearly always take much less time.
3830 These optimizations were done on purpose.
3832 If you find the Calc module to slow, try to install any of the replacement
3833 modules and see if they help you.
3835 =head2 Alternative math libraries
3837 You can use an alternative library to drive Math::BigInt via:
3839 use Math::BigInt lib => 'Module';
3841 See L<MATH LIBRARY> for more information.
3843 For more benchmark results see L<http://bloodgate.com/perl/benchmarks.html>.
3847 =head1 Subclassing Math::BigInt
3849 The basic design of Math::BigInt allows simple subclasses with very little
3850 work, as long as a few simple rules are followed:
3856 The public API must remain consistent, i.e. if a sub-class is overloading
3857 addition, the sub-class must use the same name, in this case badd(). The
3858 reason for this is that Math::BigInt is optimized to call the object methods
3863 The private object hash keys like C<$x->{sign}> may not be changed, but
3864 additional keys can be added, like C<$x->{_custom}>.
3868 Accessor functions are available for all existing object hash keys and should
3869 be used instead of directly accessing the internal hash keys. The reason for
3870 this is that Math::BigInt itself has a pluggable interface which permits it
3871 to support different storage methods.
3875 More complex sub-classes may have to replicate more of the logic internal of
3876 Math::BigInt if they need to change more basic behaviors. A subclass that
3877 needs to merely change the output only needs to overload C<bstr()>.
3879 All other object methods and overloaded functions can be directly inherited
3880 from the parent class.
3882 At the very minimum, any subclass will need to provide it's own C<new()> and can
3883 store additional hash keys in the object. There are also some package globals
3884 that must be defined, e.g.:
3888 $precision = -2; # round to 2 decimal places
3889 $round_mode = 'even';
3892 Additionally, you might want to provide the following two globals to allow
3893 auto-upgrading and auto-downgrading to work correctly:
3898 This allows Math::BigInt to correctly retrieve package globals from the
3899 subclass, like C<$SubClass::precision>. See t/Math/BigInt/Subclass.pm or
3900 t/Math/BigFloat/SubClass.pm completely functional subclass examples.
3906 in your subclass to automatically inherit the overloading from the parent. If
3907 you like, you can change part of the overloading, look at Math::String for an
3912 When used like this:
3914 use Math::BigInt upgrade => 'Foo::Bar';
3916 certain operations will 'upgrade' their calculation and thus the result to
3917 the class Foo::Bar. Usually this is used in conjunction with Math::BigFloat:
3919 use Math::BigInt upgrade => 'Math::BigFloat';
3921 As a shortcut, you can use the module C<bignum>:
3925 Also good for oneliners:
3927 perl -Mbignum -le 'print 2 ** 255'
3929 This makes it possible to mix arguments of different classes (as in 2.5 + 2)
3930 as well es preserve accuracy (as in sqrt(3)).
3932 Beware: This feature is not fully implemented yet.
3936 The following methods upgrade themselves unconditionally; that is if upgrade
3937 is in effect, they will always hand up their work:
3949 Beware: This list is not complete.
3951 All other methods upgrade themselves only when one (or all) of their
3952 arguments are of the class mentioned in $upgrade (This might change in later
3953 versions to a more sophisticated scheme):
3959 =item broot() does not work
3961 The broot() function in BigInt may only work for small values. This will be
3962 fixed in a later version.
3964 =item Out of Memory!
3966 Under Perl prior to 5.6.0 having an C<use Math::BigInt ':constant';> and
3967 C<eval()> in your code will crash with "Out of memory". This is probably an
3968 overload/exporter bug. You can workaround by not having C<eval()>
3969 and ':constant' at the same time or upgrade your Perl to a newer version.
3971 =item Fails to load Calc on Perl prior 5.6.0
3973 Since eval(' use ...') can not be used in conjunction with ':constant', BigInt
3974 will fall back to eval { require ... } when loading the math lib on Perls
3975 prior to 5.6.0. This simple replaces '::' with '/' and thus might fail on
3976 filesystems using a different seperator.
3982 Some things might not work as you expect them. Below is documented what is
3983 known to be troublesome:
3987 =item bstr(), bsstr() and 'cmp'
3989 Both C<bstr()> and C<bsstr()> as well as automated stringify via overload now
3990 drop the leading '+'. The old code would return '+3', the new returns '3'.
3991 This is to be consistent with Perl and to make C<cmp> (especially with
3992 overloading) to work as you expect. It also solves problems with C<Test.pm>,
3993 because it's C<ok()> uses 'eq' internally.
3995 Mark Biggar said, when asked about to drop the '+' altogether, or make only
3998 I agree (with the first alternative), don't add the '+' on positive
3999 numbers. It's not as important anymore with the new internal
4000 form for numbers. It made doing things like abs and neg easier,
4001 but those have to be done differently now anyway.
4003 So, the following examples will now work all as expected:
4006 BEGIN { plan tests => 1 }
4009 my $x = new Math::BigInt 3*3;
4010 my $y = new Math::BigInt 3*3;
4013 print "$x eq 9" if $x eq $y;
4014 print "$x eq 9" if $x eq '9';
4015 print "$x eq 9" if $x eq 3*3;
4017 Additionally, the following still works:
4019 print "$x == 9" if $x == $y;
4020 print "$x == 9" if $x == 9;
4021 print "$x == 9" if $x == 3*3;
4023 There is now a C<bsstr()> method to get the string in scientific notation aka
4024 C<1e+2> instead of C<100>. Be advised that overloaded 'eq' always uses bstr()
4025 for comparisation, but Perl will represent some numbers as 100 and others
4026 as 1e+308. If in doubt, convert both arguments to Math::BigInt before
4027 comparing them as strings:
4030 BEGIN { plan tests => 3 }
4033 $x = Math::BigInt->new('1e56'); $y = 1e56;
4034 ok ($x,$y); # will fail
4035 ok ($x->bsstr(),$y); # okay
4036 $y = Math::BigInt->new($y);
4039 Alternatively, simple use C<< <=> >> for comparisations, this will get it
4040 always right. There is not yet a way to get a number automatically represented
4041 as a string that matches exactly the way Perl represents it.
4045 C<int()> will return (at least for Perl v5.7.1 and up) another BigInt, not a
4048 $x = Math::BigInt->new(123);
4049 $y = int($x); # BigInt 123
4050 $x = Math::BigFloat->new(123.45);
4051 $y = int($x); # BigInt 123
4053 In all Perl versions you can use C<as_number()> for the same effect:
4055 $x = Math::BigFloat->new(123.45);
4056 $y = $x->as_number(); # BigInt 123
4058 This also works for other subclasses, like Math::String.
4060 It is yet unlcear whether overloaded int() should return a scalar or a BigInt.
4064 The following will probably not do what you expect:
4066 $c = Math::BigInt->new(123);
4067 print $c->length(),"\n"; # prints 30
4069 It prints both the number of digits in the number and in the fraction part
4070 since print calls C<length()> in list context. Use something like:
4072 print scalar $c->length(),"\n"; # prints 3
4076 The following will probably not do what you expect:
4078 print $c->bdiv(10000),"\n";
4080 It prints both quotient and remainder since print calls C<bdiv()> in list
4081 context. Also, C<bdiv()> will modify $c, so be carefull. You probably want
4084 print $c / 10000,"\n";
4085 print scalar $c->bdiv(10000),"\n"; # or if you want to modify $c
4089 The quotient is always the greatest integer less than or equal to the
4090 real-valued quotient of the two operands, and the remainder (when it is
4091 nonzero) always has the same sign as the second operand; so, for
4101 As a consequence, the behavior of the operator % agrees with the
4102 behavior of Perl's built-in % operator (as documented in the perlop
4103 manpage), and the equation
4105 $x == ($x / $y) * $y + ($x % $y)
4107 holds true for any $x and $y, which justifies calling the two return
4108 values of bdiv() the quotient and remainder. The only exception to this rule
4109 are when $y == 0 and $x is negative, then the remainder will also be
4110 negative. See below under "infinity handling" for the reasoning behing this.
4112 Perl's 'use integer;' changes the behaviour of % and / for scalars, but will
4113 not change BigInt's way to do things. This is because under 'use integer' Perl
4114 will do what the underlying C thinks is right and this is different for each
4115 system. If you need BigInt's behaving exactly like Perl's 'use integer', bug
4116 the author to implement it ;)
4118 =item infinity handling
4120 Here are some examples that explain the reasons why certain results occur while
4123 The following table shows the result of the division and the remainder, so that
4124 the equation above holds true. Some "ordinary" cases are strewn in to show more
4125 clearly the reasoning:
4127 A / B = C, R so that C * B + R = A
4128 =========================================================
4129 5 / 8 = 0, 5 0 * 8 + 5 = 5
4130 0 / 8 = 0, 0 0 * 8 + 0 = 0
4131 0 / inf = 0, 0 0 * inf + 0 = 0
4132 0 /-inf = 0, 0 0 * -inf + 0 = 0
4133 5 / inf = 0, 5 0 * inf + 5 = 5
4134 5 /-inf = 0, 5 0 * -inf + 5 = 5
4135 -5/ inf = 0, -5 0 * inf + -5 = -5
4136 -5/-inf = 0, -5 0 * -inf + -5 = -5
4137 inf/ 5 = inf, 0 inf * 5 + 0 = inf
4138 -inf/ 5 = -inf, 0 -inf * 5 + 0 = -inf
4139 inf/ -5 = -inf, 0 -inf * -5 + 0 = inf
4140 -inf/ -5 = inf, 0 inf * -5 + 0 = -inf
4141 5/ 5 = 1, 0 1 * 5 + 0 = 5
4142 -5/ -5 = 1, 0 1 * -5 + 0 = -5
4143 inf/ inf = 1, 0 1 * inf + 0 = inf
4144 -inf/-inf = 1, 0 1 * -inf + 0 = -inf
4145 inf/-inf = -1, 0 -1 * -inf + 0 = inf
4146 -inf/ inf = -1, 0 1 * -inf + 0 = -inf
4147 8/ 0 = inf, 8 inf * 0 + 8 = 8
4148 inf/ 0 = inf, inf inf * 0 + inf = inf
4151 These cases below violate the "remainder has the sign of the second of the two
4152 arguments", since they wouldn't match up otherwise.
4154 A / B = C, R so that C * B + R = A
4155 ========================================================
4156 -inf/ 0 = -inf, -inf -inf * 0 + inf = -inf
4157 -8/ 0 = -inf, -8 -inf * 0 + 8 = -8
4159 =item Modifying and =
4163 $x = Math::BigFloat->new(5);
4166 It will not do what you think, e.g. making a copy of $x. Instead it just makes
4167 a second reference to the B<same> object and stores it in $y. Thus anything
4168 that modifies $x (except overloaded operators) will modify $y, and vice versa.
4169 Or in other words, C<=> is only safe if you modify your BigInts only via
4170 overloaded math. As soon as you use a method call it breaks:
4173 print "$x, $y\n"; # prints '10, 10'
4175 If you want a true copy of $x, use:
4179 You can also chain the calls like this, this will make first a copy and then
4182 $y = $x->copy()->bmul(2);
4184 See also the documentation for overload.pm regarding C<=>.
4188 C<bpow()> (and the rounding functions) now modifies the first argument and
4189 returns it, unlike the old code which left it alone and only returned the
4190 result. This is to be consistent with C<badd()> etc. The first three will
4191 modify $x, the last one won't:
4193 print bpow($x,$i),"\n"; # modify $x
4194 print $x->bpow($i),"\n"; # ditto
4195 print $x **= $i,"\n"; # the same
4196 print $x ** $i,"\n"; # leave $x alone
4198 The form C<$x **= $y> is faster than C<$x = $x ** $y;>, though.
4200 =item Overloading -$x
4210 since overload calls C<sub($x,0,1);> instead of C<neg($x)>. The first variant
4211 needs to preserve $x since it does not know that it later will get overwritten.
4212 This makes a copy of $x and takes O(N), but $x->bneg() is O(1).
4214 With Copy-On-Write, this issue would be gone, but C-o-W is not implemented
4215 since it is slower for all other things.
4217 =item Mixing different object types
4219 In Perl you will get a floating point value if you do one of the following:
4225 With overloaded math, only the first two variants will result in a BigFloat:
4230 $mbf = Math::BigFloat->new(5);
4231 $mbi2 = Math::BigInteger->new(5);
4232 $mbi = Math::BigInteger->new(2);
4234 # what actually gets called:
4235 $float = $mbf + $mbi; # $mbf->badd()
4236 $float = $mbf / $mbi; # $mbf->bdiv()
4237 $integer = $mbi + $mbf; # $mbi->badd()
4238 $integer = $mbi2 / $mbi; # $mbi2->bdiv()
4239 $integer = $mbi2 / $mbf; # $mbi2->bdiv()
4241 This is because math with overloaded operators follows the first (dominating)
4242 operand, and the operation of that is called and returns thus the result. So,
4243 Math::BigInt::bdiv() will always return a Math::BigInt, regardless whether
4244 the result should be a Math::BigFloat or the second operant is one.
4246 To get a Math::BigFloat you either need to call the operation manually,
4247 make sure the operands are already of the proper type or casted to that type
4248 via Math::BigFloat->new():
4250 $float = Math::BigFloat->new($mbi2) / $mbi; # = 2.5
4252 Beware of simple "casting" the entire expression, this would only convert
4253 the already computed result:
4255 $float = Math::BigFloat->new($mbi2 / $mbi); # = 2.0 thus wrong!
4257 Beware also of the order of more complicated expressions like:
4259 $integer = ($mbi2 + $mbi) / $mbf; # int / float => int
4260 $integer = $mbi2 / Math::BigFloat->new($mbi); # ditto
4262 If in doubt, break the expression into simpler terms, or cast all operands
4263 to the desired resulting type.
4265 Scalar values are a bit different, since:
4270 will both result in the proper type due to the way the overloaded math works.
4272 This section also applies to other overloaded math packages, like Math::String.
4274 One solution to you problem might be autoupgrading|upgrading. See the
4275 pragmas L<bignum>, L<bigint> and L<bigrat> for an easy way to do this.
4279 C<bsqrt()> works only good if the result is a big integer, e.g. the square
4280 root of 144 is 12, but from 12 the square root is 3, regardless of rounding
4281 mode. The reason is that the result is always truncated to an integer.
4283 If you want a better approximation of the square root, then use:
4285 $x = Math::BigFloat->new(12);
4286 Math::BigFloat->precision(0);
4287 Math::BigFloat->round_mode('even');
4288 print $x->copy->bsqrt(),"\n"; # 4
4290 Math::BigFloat->precision(2);
4291 print $x->bsqrt(),"\n"; # 3.46
4292 print $x->bsqrt(3),"\n"; # 3.464
4296 For negative numbers in base see also L<brsft|brsft>.
4302 This program is free software; you may redistribute it and/or modify it under
4303 the same terms as Perl itself.
4307 L<Math::BigFloat>, L<Math::BigRat> and L<Math::Big> as well as
4308 L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>.
4310 The pragmas L<bignum>, L<bigint> and L<bigrat> also might be of interest
4311 because they solve the autoupgrading/downgrading issue, at least partly.
4314 L<http://search.cpan.org/search?mode=module&query=Math%3A%3ABigInt> contains
4315 more documentation including a full version history, testcases, empty
4316 subclass files and benchmarks.
4320 Original code by Mark Biggar, overloaded interface by Ilya Zakharevich.
4321 Completely rewritten by Tels http://bloodgate.com in late 2000, 2001 - 2003
4322 and still at it in 2004.
4324 Many people contributed in one or more ways to the final beast, see the file
4325 CREDITS for an (uncomplete) list. If you miss your name, please drop me a