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 # not supported by Perl yet
59 '..' => \&_pointpoint,
61 '<=>' => sub { $_[2] ?
62 ref($_[0])->bcmp($_[1],$_[0]) :
66 "$_[1]" cmp $_[0]->bstr() :
67 $_[0]->bstr() cmp "$_[1]" },
69 # make cos()/sin()/exp() "work" with BigInt's or subclasses
70 'cos' => sub { cos($_[0]->numify()) },
71 'sin' => sub { sin($_[0]->numify()) },
72 'exp' => sub { exp($_[0]->numify()) },
73 'atan2' => sub { atan2($_[0]->numify(),$_[1]) },
75 'log' => sub { $_[0]->copy()->blog($_[1]); },
76 'int' => sub { $_[0]->copy(); },
77 'neg' => sub { $_[0]->copy()->bneg(); },
78 'abs' => sub { $_[0]->copy()->babs(); },
79 'sqrt' => sub { $_[0]->copy()->bsqrt(); },
80 '~' => sub { $_[0]->copy()->bnot(); },
82 # for sub it is a bit tricky to keep b: b-a => -a+b
83 '-' => sub { my $c = $_[0]->copy; $_[2] ?
84 $c->bneg()->badd($_[1]) :
86 '+' => sub { $_[0]->copy()->badd($_[1]); },
87 '*' => sub { $_[0]->copy()->bmul($_[1]); },
90 $_[2] ? ref($_[0])->new($_[1])->bdiv($_[0]) : $_[0]->copy->bdiv($_[1]);
93 $_[2] ? ref($_[0])->new($_[1])->bmod($_[0]) : $_[0]->copy->bmod($_[1]);
96 $_[2] ? ref($_[0])->new($_[1])->bpow($_[0]) : $_[0]->copy->bpow($_[1]);
99 $_[2] ? ref($_[0])->new($_[1])->blsft($_[0]) : $_[0]->copy->blsft($_[1]);
102 $_[2] ? ref($_[0])->new($_[1])->brsft($_[0]) : $_[0]->copy->brsft($_[1]);
105 $_[2] ? ref($_[0])->new($_[1])->band($_[0]) : $_[0]->copy->band($_[1]);
108 $_[2] ? ref($_[0])->new($_[1])->bior($_[0]) : $_[0]->copy->bior($_[1]);
111 $_[2] ? ref($_[0])->new($_[1])->bxor($_[0]) : $_[0]->copy->bxor($_[1]);
114 # can modify arg of ++ and --, so avoid a copy() for speed, but don't
115 # use $_[0]->bone(), it would modify $_[0] to be 1!
116 '++' => sub { $_[0]->binc() },
117 '--' => sub { $_[0]->bdec() },
119 # if overloaded, O(1) instead of O(N) and twice as fast for small numbers
121 # this kludge is needed for perl prior 5.6.0 since returning 0 here fails :-/
122 # v5.6.1 dumps on this: return !$_[0]->is_zero() || undef; :-(
124 $t = 1 if !$_[0]->is_zero();
128 # the original qw() does not work with the TIESCALAR below, why?
129 # Order of arguments unsignificant
130 '""' => sub { $_[0]->bstr(); },
131 '0+' => sub { $_[0]->numify(); }
134 ##############################################################################
135 # global constants, flags and accessory
137 # these are public, but their usage is not recommended, use the accessor
140 $round_mode = 'even'; # one of 'even', 'odd', '+inf', '-inf', 'zero' or 'trunc'
145 $upgrade = undef; # default is no upgrade
146 $downgrade = undef; # default is no downgrade
148 # these are internally, and not to be used from the outside
150 sub MB_NEVER_ROUND () { 0x0001; }
152 $_trap_nan = 0; # are NaNs ok? set w/ config()
153 $_trap_inf = 0; # are infs ok? set w/ config()
154 my $nan = 'NaN'; # constants for easier life
156 my $CALC = 'Math::BigInt::Calc'; # module to do the low level math
158 my $IMPORT = 0; # was import() called yet?
159 # used to make require work
160 my %WARN; # warn only once for low-level libs
161 my %CAN; # cache for $CALC->can(...)
162 my $EMU_LIB = 'Math/BigInt/CalcEmu.pm'; # emulate low-level math
164 ##############################################################################
165 # the old code had $rnd_mode, so we need to support it, too
168 sub TIESCALAR { my ($class) = @_; bless \$round_mode, $class; }
169 sub FETCH { return $round_mode; }
170 sub STORE { $rnd_mode = $_[0]->round_mode($_[1]); }
174 # tie to enable $rnd_mode to work transparently
175 tie $rnd_mode, 'Math::BigInt';
177 # set up some handy alias names
178 *as_int = \&as_number;
179 *is_pos = \&is_positive;
180 *is_neg = \&is_negative;
183 ##############################################################################
188 # make Class->round_mode() work
190 my $class = ref($self) || $self || __PACKAGE__;
194 if ($m !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
196 require Carp; Carp::croak ("Unknown round mode '$m'");
198 return ${"${class}::round_mode"} = $m;
200 ${"${class}::round_mode"};
206 # make Class->upgrade() work
208 my $class = ref($self) || $self || __PACKAGE__;
209 # need to set new value?
213 return ${"${class}::upgrade"} = $u;
215 ${"${class}::upgrade"};
221 # make Class->downgrade() work
223 my $class = ref($self) || $self || __PACKAGE__;
224 # need to set new value?
228 return ${"${class}::downgrade"} = $u;
230 ${"${class}::downgrade"};
236 # make Class->div_scale() work
238 my $class = ref($self) || $self || __PACKAGE__;
243 require Carp; Carp::croak ('div_scale must be greater than zero');
245 ${"${class}::div_scale"} = shift;
247 ${"${class}::div_scale"};
252 # $x->accuracy($a); ref($x) $a
253 # $x->accuracy(); ref($x)
254 # Class->accuracy(); class
255 # Class->accuracy($a); class $a
258 my $class = ref($x) || $x || __PACKAGE__;
261 # need to set new value?
265 # convert objects to scalars to avoid deep recursion. If object doesn't
266 # have numify(), then hopefully it will have overloading for int() and
267 # boolean test without wandering into a deep recursion path...
268 $a = $a->numify() if ref($a) && $a->can('numify');
272 # also croak on non-numerical
276 Carp::croak ('Argument to accuracy must be greater than zero');
280 require Carp; Carp::croak ('Argument to accuracy must be an integer');
285 # $object->accuracy() or fallback to global
286 $x->bround($a) if $a; # not for undef, 0
287 $x->{_a} = $a; # set/overwrite, even if not rounded
288 delete $x->{_p}; # clear P
289 $a = ${"${class}::accuracy"} unless defined $a; # proper return value
293 ${"${class}::accuracy"} = $a; # set global A
294 ${"${class}::precision"} = undef; # clear global P
296 return $a; # shortcut
300 # $object->accuracy() or fallback to global
301 $r = $x->{_a} if ref($x);
302 # but don't return global undef, when $x's accuracy is 0!
303 $r = ${"${class}::accuracy"} if !defined $r;
309 # $x->precision($p); ref($x) $p
310 # $x->precision(); ref($x)
311 # Class->precision(); class
312 # Class->precision($p); class $p
315 my $class = ref($x) || $x || __PACKAGE__;
321 # convert objects to scalars to avoid deep recursion. If object doesn't
322 # have numify(), then hopefully it will have overloading for int() and
323 # boolean test without wandering into a deep recursion path...
324 $p = $p->numify() if ref($p) && $p->can('numify');
325 if ((defined $p) && (int($p) != $p))
327 require Carp; Carp::croak ('Argument to precision must be an integer');
331 # $object->precision() or fallback to global
332 $x->bfround($p) if $p; # not for undef, 0
333 $x->{_p} = $p; # set/overwrite, even if not rounded
334 delete $x->{_a}; # clear A
335 $p = ${"${class}::precision"} unless defined $p; # proper return value
339 ${"${class}::precision"} = $p; # set global P
340 ${"${class}::accuracy"} = undef; # clear global A
342 return $p; # shortcut
346 # $object->precision() or fallback to global
347 $r = $x->{_p} if ref($x);
348 # but don't return global undef, when $x's precision is 0!
349 $r = ${"${class}::precision"} if !defined $r;
355 # return (or set) configuration data as hash ref
356 my $class = shift || 'Math::BigInt';
361 # try to set given options as arguments from hash
364 if (ref($args) ne 'HASH')
368 # these values can be "set"
372 upgrade downgrade precision accuracy round_mode div_scale/
375 $set_args->{$key} = $args->{$key} if exists $args->{$key};
376 delete $args->{$key};
381 Carp::croak ("Illegal key(s) '",
382 join("','",keys %$args),"' passed to $class\->config()");
384 foreach my $key (keys %$set_args)
386 if ($key =~ /^trap_(inf|nan)\z/)
388 ${"${class}::_trap_$1"} = ($set_args->{"trap_$1"} ? 1 : 0);
391 # use a call instead of just setting the $variable to check argument
392 $class->$key($set_args->{$key});
396 # now return actual configuration
400 lib_version => ${"${CALC}::VERSION"},
402 trap_nan => ${"${class}::_trap_nan"},
403 trap_inf => ${"${class}::_trap_inf"},
404 version => ${"${class}::VERSION"},
407 upgrade downgrade precision accuracy round_mode div_scale
410 $cfg->{$key} = ${"${class}::$key"};
417 # select accuracy parameter based on precedence,
418 # used by bround() and bfround(), may return undef for scale (means no op)
419 my ($x,$s,$m,$scale,$mode) = @_;
420 $scale = $x->{_a} if !defined $scale;
421 $scale = $s if (!defined $scale);
422 $mode = $m if !defined $mode;
423 return ($scale,$mode);
428 # select precision parameter based on precedence,
429 # used by bround() and bfround(), may return undef for scale (means no op)
430 my ($x,$s,$m,$scale,$mode) = @_;
431 $scale = $x->{_p} if !defined $scale;
432 $scale = $s if (!defined $scale);
433 $mode = $m if !defined $mode;
434 return ($scale,$mode);
437 ##############################################################################
445 # if two arguments, the first one is the class to "swallow" subclasses
453 return unless ref($x); # only for objects
455 my $self = {}; bless $self,$c;
457 $self->{sign} = $x->{sign};
458 $self->{value} = $CALC->_copy($x->{value});
459 $self->{_a} = $x->{_a} if defined $x->{_a};
460 $self->{_p} = $x->{_p} if defined $x->{_p};
466 # create a new BigInt object from a string or another BigInt object.
467 # see hash keys documented at top
469 # the argument could be an object, so avoid ||, && etc on it, this would
470 # cause costly overloaded code to be called. The only allowed ops are
473 my ($class,$wanted,$a,$p,$r) = @_;
475 # avoid numify-calls by not using || on $wanted!
476 return $class->bzero($a,$p) if !defined $wanted; # default to 0
477 return $class->copy($wanted,$a,$p,$r)
478 if ref($wanted) && $wanted->isa($class); # MBI or subclass
480 $class->import() if $IMPORT == 0; # make require work
482 my $self = bless {}, $class;
484 # shortcut for "normal" numbers
485 if ((!ref $wanted) && ($wanted =~ /^([+-]?)[1-9][0-9]*\z/))
487 $self->{sign} = $1 || '+';
489 if ($wanted =~ /^[+-]/)
491 # remove sign without touching wanted to make it work with constants
492 my $t = $wanted; $t =~ s/^[+-]//;
493 $self->{value} = $CALC->_new($t);
497 $self->{value} = $CALC->_new($wanted);
500 if ( (defined $a) || (defined $p)
501 || (defined ${"${class}::precision"})
502 || (defined ${"${class}::accuracy"})
505 $self->round($a,$p,$r) unless (@_ == 4 && !defined $a && !defined $p);
510 # handle '+inf', '-inf' first
511 if ($wanted =~ /^[+-]?inf$/)
513 $self->{value} = $CALC->_zero();
514 $self->{sign} = $wanted; $self->{sign} = '+inf' if $self->{sign} eq 'inf';
517 # split str in m mantissa, e exponent, i integer, f fraction, v value, s sign
518 my ($mis,$miv,$mfv,$es,$ev) = _split($wanted);
523 require Carp; Carp::croak("$wanted is not a number in $class");
525 $self->{value} = $CALC->_zero();
526 $self->{sign} = $nan;
531 # _from_hex or _from_bin
532 $self->{value} = $mis->{value};
533 $self->{sign} = $mis->{sign};
534 return $self; # throw away $mis
536 # make integer from mantissa by adjusting exp, then convert to bigint
537 $self->{sign} = $$mis; # store sign
538 $self->{value} = $CALC->_zero(); # for all the NaN cases
539 my $e = int("$$es$$ev"); # exponent (avoid recursion)
542 my $diff = $e - CORE::length($$mfv);
543 if ($diff < 0) # Not integer
547 require Carp; Carp::croak("$wanted not an integer in $class");
550 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
551 $self->{sign} = $nan;
555 # adjust fraction and add it to value
556 #print "diff > 0 $$miv\n";
557 $$miv = $$miv . ($$mfv . '0' x $diff);
562 if ($$mfv ne '') # e <= 0
564 # fraction and negative/zero E => NOI
567 require Carp; Carp::croak("$wanted not an integer in $class");
569 #print "NOI 2 \$\$mfv '$$mfv'\n";
570 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
571 $self->{sign} = $nan;
575 # xE-y, and empty mfv
578 if ($$miv !~ s/0{$e}$//) # can strip so many zero's?
582 require Carp; Carp::croak("$wanted not an integer in $class");
585 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
586 $self->{sign} = $nan;
590 $self->{sign} = '+' if $$miv eq '0'; # normalize -0 => +0
591 $self->{value} = $CALC->_new($$miv) if $self->{sign} =~ /^[+-]$/;
592 # if any of the globals is set, use them to round and store them inside $self
593 # do not round for new($x,undef,undef) since that is used by MBF to signal
595 $self->round($a,$p,$r) unless @_ == 4 && !defined $a && !defined $p;
601 # create a bigint 'NaN', if given a BigInt, set it to 'NaN'
603 $self = $class if !defined $self;
606 my $c = $self; $self = {}; bless $self, $c;
609 if (${"${class}::_trap_nan"})
612 Carp::croak ("Tried to set $self to NaN in $class\::bnan()");
614 $self->import() if $IMPORT == 0; # make require work
615 return if $self->modify('bnan');
616 if ($self->can('_bnan'))
618 # use subclass to initialize
623 # otherwise do our own thing
624 $self->{value} = $CALC->_zero();
626 $self->{sign} = $nan;
627 delete $self->{_a}; delete $self->{_p}; # rounding NaN is silly
633 # create a bigint '+-inf', if given a BigInt, set it to '+-inf'
634 # the sign is either '+', or if given, used from there
636 my $sign = shift; $sign = '+' if !defined $sign || $sign !~ /^-(inf)?$/;
637 $self = $class if !defined $self;
640 my $c = $self; $self = {}; bless $self, $c;
643 if (${"${class}::_trap_inf"})
646 Carp::croak ("Tried to set $self to +-inf in $class\::binfn()");
648 $self->import() if $IMPORT == 0; # make require work
649 return if $self->modify('binf');
650 if ($self->can('_binf'))
652 # use subclass to initialize
657 # otherwise do our own thing
658 $self->{value} = $CALC->_zero();
660 $sign = $sign . 'inf' if $sign !~ /inf$/; # - => -inf
661 $self->{sign} = $sign;
662 ($self->{_a},$self->{_p}) = @_; # take over requested rounding
668 # create a bigint '+0', if given a BigInt, set it to 0
670 $self = $class if !defined $self;
674 my $c = $self; $self = {}; bless $self, $c;
676 $self->import() if $IMPORT == 0; # make require work
677 return if $self->modify('bzero');
679 if ($self->can('_bzero'))
681 # use subclass to initialize
686 # otherwise do our own thing
687 $self->{value} = $CALC->_zero();
694 # call like: $x->bzero($a,$p,$r,$y);
695 ($self,$self->{_a},$self->{_p}) = $self->_find_round_parameters(@_);
700 if ( (!defined $self->{_a}) || (defined $_[0] && $_[0] > $self->{_a}));
702 if ( (!defined $self->{_p}) || (defined $_[1] && $_[1] > $self->{_p}));
710 # create a bigint '+1' (or -1 if given sign '-'),
711 # if given a BigInt, set it to +1 or -1, respecively
713 my $sign = shift; $sign = '+' if !defined $sign || $sign ne '-';
714 $self = $class if !defined $self;
718 my $c = $self; $self = {}; bless $self, $c;
720 $self->import() if $IMPORT == 0; # make require work
721 return if $self->modify('bone');
723 if ($self->can('_bone'))
725 # use subclass to initialize
730 # otherwise do our own thing
731 $self->{value} = $CALC->_one();
733 $self->{sign} = $sign;
738 # call like: $x->bone($sign,$a,$p,$r,$y);
739 ($self,$self->{_a},$self->{_p}) = $self->_find_round_parameters(@_);
743 # call like: $x->bone($sign,$a,$p,$r);
745 if ( (!defined $self->{_a}) || (defined $_[0] && $_[0] > $self->{_a}));
747 if ( (!defined $self->{_p}) || (defined $_[1] && $_[1] > $self->{_p}));
753 ##############################################################################
754 # string conversation
758 # (ref to BFLOAT or num_str ) return num_str
759 # Convert number from internal format to scientific string format.
760 # internal format is always normalized (no leading zeros, "-0E0" => "+0E0")
761 my $x = shift; $class = ref($x) || $x; $x = $class->new(shift) if !ref($x);
762 # my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
764 if ($x->{sign} !~ /^[+-]$/)
766 return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
769 my ($m,$e) = $x->parts();
770 #$m->bstr() . 'e+' . $e->bstr(); # e can only be positive in BigInt
771 # 'e+' because E can only be positive in BigInt
772 $m->bstr() . 'e+' . $CALC->_str($e->{value});
777 # make a string from bigint object
778 my $x = shift; $class = ref($x) || $x; $x = $class->new(shift) if !ref($x);
779 # my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
781 if ($x->{sign} !~ /^[+-]$/)
783 return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
786 my $es = ''; $es = $x->{sign} if $x->{sign} eq '-';
787 $es.$CALC->_str($x->{value});
792 # Make a "normal" scalar from a BigInt object
793 my $x = shift; $x = $class->new($x) unless ref $x;
795 return $x->bstr() if $x->{sign} !~ /^[+-]$/;
796 my $num = $CALC->_num($x->{value});
797 return -$num if $x->{sign} eq '-';
801 ##############################################################################
802 # public stuff (usually prefixed with "b")
806 # return the sign of the number: +/-/-inf/+inf/NaN
807 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
812 sub _find_round_parameters
814 # After any operation or when calling round(), the result is rounded by
815 # regarding the A & P from arguments, local parameters, or globals.
817 # !!!!!!! If you change this, remember to change round(), too! !!!!!!!!!!
819 # This procedure finds the round parameters, but it is for speed reasons
820 # duplicated in round. Otherwise, it is tested by the testsuite and used
823 # returns ($self) or ($self,$a,$p,$r) - sets $self to NaN of both A and P
824 # were requested/defined (locally or globally or both)
826 my ($self,$a,$p,$r,@args) = @_;
827 # $a accuracy, if given by caller
828 # $p precision, if given by caller
829 # $r round_mode, if given by caller
830 # @args all 'other' arguments (0 for unary, 1 for binary ops)
832 # leave bigfloat parts alone
833 return ($self) if exists $self->{_f} && ($self->{_f} & MB_NEVER_ROUND) != 0;
835 my $c = ref($self); # find out class of argument(s)
838 # now pick $a or $p, but only if we have got "arguments"
841 foreach ($self,@args)
843 # take the defined one, or if both defined, the one that is smaller
844 $a = $_->{_a} if (defined $_->{_a}) && (!defined $a || $_->{_a} < $a);
849 # even if $a is defined, take $p, to signal error for both defined
850 foreach ($self,@args)
852 # take the defined one, or if both defined, the one that is bigger
854 $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} > $p);
857 # if still none defined, use globals (#2)
858 $a = ${"$c\::accuracy"} unless defined $a;
859 $p = ${"$c\::precision"} unless defined $p;
861 # A == 0 is useless, so undef it to signal no rounding
862 $a = undef if defined $a && $a == 0;
865 return ($self) unless defined $a || defined $p; # early out
867 # set A and set P is an fatal error
868 return ($self->bnan()) if defined $a && defined $p; # error
870 $r = ${"$c\::round_mode"} unless defined $r;
871 if ($r !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
873 require Carp; Carp::croak ("Unknown round mode '$r'");
881 # Round $self according to given parameters, or given second argument's
882 # parameters or global defaults
884 # for speed reasons, _find_round_parameters is embeded here:
886 my ($self,$a,$p,$r,@args) = @_;
887 # $a accuracy, if given by caller
888 # $p precision, if given by caller
889 # $r round_mode, if given by caller
890 # @args all 'other' arguments (0 for unary, 1 for binary ops)
892 # leave bigfloat parts alone
893 return ($self) if exists $self->{_f} && ($self->{_f} & MB_NEVER_ROUND) != 0;
895 my $c = ref($self); # find out class of argument(s)
898 # now pick $a or $p, but only if we have got "arguments"
901 foreach ($self,@args)
903 # take the defined one, or if both defined, the one that is smaller
904 $a = $_->{_a} if (defined $_->{_a}) && (!defined $a || $_->{_a} < $a);
909 # even if $a is defined, take $p, to signal error for both defined
910 foreach ($self,@args)
912 # take the defined one, or if both defined, the one that is bigger
914 $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} > $p);
917 # if still none defined, use globals (#2)
918 $a = ${"$c\::accuracy"} unless defined $a;
919 $p = ${"$c\::precision"} unless defined $p;
921 # A == 0 is useless, so undef it to signal no rounding
922 $a = undef if defined $a && $a == 0;
925 return $self unless defined $a || defined $p; # early out
927 # set A and set P is an fatal error
928 return $self->bnan() if defined $a && defined $p;
930 $r = ${"$c\::round_mode"} unless defined $r;
931 if ($r !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
933 require Carp; Carp::croak ("Unknown round mode '$r'");
936 # now round, by calling either fround or ffround:
939 $self->bround($a,$r) if !defined $self->{_a} || $self->{_a} >= $a;
941 else # both can't be undefined due to early out
943 $self->bfround($p,$r) if !defined $self->{_p} || $self->{_p} <= $p;
945 $self->bnorm(); # after round, normalize
950 # (numstr or BINT) return BINT
951 # Normalize number -- no-op here
952 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
958 # (BINT or num_str) return BINT
959 # make number absolute, or return absolute BINT from string
960 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
962 return $x if $x->modify('babs');
963 # post-normalized abs for internal use (does nothing for NaN)
964 $x->{sign} =~ s/^-/+/;
970 # (BINT or num_str) return BINT
971 # negate number or make a negated number from string
972 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
974 return $x if $x->modify('bneg');
976 # for +0 dont negate (to have always normalized)
977 $x->{sign} =~ tr/+-/-+/ if !$x->is_zero(); # does nothing for NaN
983 # Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort)
984 # (BINT or num_str, BINT or num_str) return cond_code
987 my ($self,$x,$y) = (ref($_[0]),@_);
989 # objectify is costly, so avoid it
990 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
992 ($self,$x,$y) = objectify(2,@_);
995 return $upgrade->bcmp($x,$y) if defined $upgrade &&
996 ((!$x->isa($self)) || (!$y->isa($self)));
998 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1000 # handle +-inf and NaN
1001 return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1002 return 0 if $x->{sign} eq $y->{sign} && $x->{sign} =~ /^[+-]inf$/;
1003 return +1 if $x->{sign} eq '+inf';
1004 return -1 if $x->{sign} eq '-inf';
1005 return -1 if $y->{sign} eq '+inf';
1008 # check sign for speed first
1009 return 1 if $x->{sign} eq '+' && $y->{sign} eq '-'; # does also 0 <=> -y
1010 return -1 if $x->{sign} eq '-' && $y->{sign} eq '+'; # does also -x <=> 0
1012 # have same sign, so compare absolute values. Don't make tests for zero here
1013 # because it's actually slower than testin in Calc (especially w/ Pari et al)
1015 # post-normalized compare for internal use (honors signs)
1016 if ($x->{sign} eq '+')
1018 # $x and $y both > 0
1019 return $CALC->_acmp($x->{value},$y->{value});
1023 $CALC->_acmp($y->{value},$x->{value}); # swaped acmp (lib returns 0,1,-1)
1028 # Compares 2 values, ignoring their signs.
1029 # Returns one of undef, <0, =0, >0. (suitable for sort)
1030 # (BINT, BINT) return cond_code
1033 my ($self,$x,$y) = (ref($_[0]),@_);
1034 # objectify is costly, so avoid it
1035 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1037 ($self,$x,$y) = objectify(2,@_);
1040 return $upgrade->bacmp($x,$y) if defined $upgrade &&
1041 ((!$x->isa($self)) || (!$y->isa($self)));
1043 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1045 # handle +-inf and NaN
1046 return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1047 return 0 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} =~ /^[+-]inf$/;
1048 return 1 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} !~ /^[+-]inf$/;
1051 $CALC->_acmp($x->{value},$y->{value}); # lib does only 0,1,-1
1056 # add second arg (BINT or string) to first (BINT) (modifies first)
1057 # return result as BINT
1060 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1061 # objectify is costly, so avoid it
1062 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1064 ($self,$x,$y,@r) = objectify(2,@_);
1067 return $x if $x->modify('badd');
1068 return $upgrade->badd($upgrade->new($x),$upgrade->new($y),@r) if defined $upgrade &&
1069 ((!$x->isa($self)) || (!$y->isa($self)));
1071 $r[3] = $y; # no push!
1072 # inf and NaN handling
1073 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1076 return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1078 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1080 # +inf++inf or -inf+-inf => same, rest is NaN
1081 return $x if $x->{sign} eq $y->{sign};
1084 # +-inf + something => +inf
1085 # something +-inf => +-inf
1086 $x->{sign} = $y->{sign}, return $x if $y->{sign} =~ /^[+-]inf$/;
1090 my ($sx, $sy) = ( $x->{sign}, $y->{sign} ); # get signs
1094 $x->{value} = $CALC->_add($x->{value},$y->{value}); # same sign, abs add
1098 my $a = $CALC->_acmp ($y->{value},$x->{value}); # absolute compare
1101 $x->{value} = $CALC->_sub($y->{value},$x->{value},1); # abs sub w/ swap
1106 # speedup, if equal, set result to 0
1107 $x->{value} = $CALC->_zero();
1112 $x->{value} = $CALC->_sub($x->{value}, $y->{value}); # abs sub
1115 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1121 # (BINT or num_str, BINT or num_str) return BINT
1122 # subtract second arg from first, modify first
1125 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1126 # objectify is costly, so avoid it
1127 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1129 ($self,$x,$y,@r) = objectify(2,@_);
1132 return $x if $x->modify('bsub');
1134 return $upgrade->new($x)->bsub($upgrade->new($y),@r) if defined $upgrade &&
1135 ((!$x->isa($self)) || (!$y->isa($self)));
1139 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1143 if (overload::StrVal($x) eq overload::StrVal($y))
1145 # if we get the same variable twice, the result must be zero (the code
1146 # below fails in that case)
1147 return $x->bzero(@r) if $x->{sign} =~ /^[+-]$/;
1148 return $x->bnan(); # NaN, -inf, +inf
1150 $y->{sign} =~ tr/+\-/-+/; # does nothing for NaN
1151 $x->badd($y,@r); # badd does not leave internal zeros
1152 $y->{sign} =~ tr/+\-/-+/; # refix $y (does nothing for NaN)
1153 $x; # already rounded by badd() or no round necc.
1158 # increment arg by one
1159 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1160 return $x if $x->modify('binc');
1162 if ($x->{sign} eq '+')
1164 $x->{value} = $CALC->_inc($x->{value});
1165 $x->round($a,$p,$r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1168 elsif ($x->{sign} eq '-')
1170 $x->{value} = $CALC->_dec($x->{value});
1171 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # -1 +1 => -0 => +0
1172 $x->round($a,$p,$r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1175 # inf, nan handling etc
1176 $x->badd($self->bone(),$a,$p,$r); # badd does round
1181 # decrement arg by one
1182 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1183 return $x if $x->modify('bdec');
1185 if ($x->{sign} eq '-')
1188 $x->{value} = $CALC->_inc($x->{value});
1192 return $x->badd($self->bone('-'),@r) unless $x->{sign} eq '+'; # inf/NaN
1194 if ($CALC->_is_zero($x->{value}))
1197 $x->{value} = $CALC->_one(); $x->{sign} = '-'; # 0 => -1
1202 $x->{value} = $CALC->_dec($x->{value});
1205 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1211 # calculate $x = $a ** $base + $b and return $a (e.g. the log() to base
1215 my ($self,$x,$base,@r) = (ref($_[0]),@_);
1216 # objectify is costly, so avoid it
1217 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1219 ($self,$x,$base,@r) = objectify(1,$class,@_);
1222 return $x if $x->modify('blog');
1224 # inf, -inf, NaN, <0 => NaN
1226 if $x->{sign} ne '+' || (defined $base && $base->{sign} ne '+');
1228 return $upgrade->blog($upgrade->new($x),$base,@r) if
1231 my ($rc,$exact) = $CALC->_log_int($x->{value},$base->{value});
1232 return $x->bnan() unless defined $rc; # not possible to take log?
1239 # (BINT or num_str, BINT or num_str) return BINT
1240 # does not modify arguments, but returns new object
1241 # Lowest Common Multiplicator
1243 my $y = shift; my ($x);
1250 $x = __PACKAGE__->new($y);
1255 my $y = shift; $y = $self->new($y) if !ref ($y);
1263 # (BINT or num_str, BINT or num_str) return BINT
1264 # does not modify arguments, but returns new object
1265 # GCD -- Euclids algorithm, variant C (Knuth Vol 3, pg 341 ff)
1268 $y = __PACKAGE__->new($y) if !ref($y);
1270 my $x = $y->copy()->babs(); # keep arguments
1271 return $x->bnan() if $x->{sign} !~ /^[+-]$/; # x NaN?
1275 $y = shift; $y = $self->new($y) if !ref($y);
1276 next if $y->is_zero();
1277 return $x->bnan() if $y->{sign} !~ /^[+-]$/; # y NaN?
1278 $x->{value} = $CALC->_gcd($x->{value},$y->{value}); last if $x->is_one();
1285 # (num_str or BINT) return BINT
1286 # represent ~x as twos-complement number
1287 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1288 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1290 return $x if $x->modify('bnot');
1291 $x->binc()->bneg(); # binc already does round
1294 ##############################################################################
1295 # is_foo test routines
1296 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1300 # return true if arg (BINT or num_str) is zero (array '+', '0')
1301 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1303 return 0 if $x->{sign} !~ /^\+$/; # -, NaN & +-inf aren't
1304 $CALC->_is_zero($x->{value});
1309 # return true if arg (BINT or num_str) is NaN
1310 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1312 $x->{sign} eq $nan ? 1 : 0;
1317 # return true if arg (BINT or num_str) is +-inf
1318 my ($self,$x,$sign) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1322 $sign = '[+-]inf' if $sign eq ''; # +- doesn't matter, only that's inf
1323 $sign = "[$1]inf" if $sign =~ /^([+-])(inf)?$/; # extract '+' or '-'
1324 return $x->{sign} =~ /^$sign$/ ? 1 : 0;
1326 $x->{sign} =~ /^[+-]inf$/ ? 1 : 0; # only +-inf is infinity
1331 # return true if arg (BINT or num_str) is +1, or -1 if sign is given
1332 my ($self,$x,$sign) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1334 $sign = '+' if !defined $sign || $sign ne '-';
1336 return 0 if $x->{sign} ne $sign; # -1 != +1, NaN, +-inf aren't either
1337 $CALC->_is_one($x->{value});
1342 # return true when arg (BINT or num_str) is odd, false for even
1343 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1345 return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
1346 $CALC->_is_odd($x->{value});
1351 # return true when arg (BINT or num_str) is even, false for odd
1352 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1354 return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
1355 $CALC->_is_even($x->{value});
1360 # return true when arg (BINT or num_str) is positive (>= 0)
1361 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1363 $x->{sign} =~ /^\+/ ? 1 : 0; # +inf is also positive, but NaN not
1368 # return true when arg (BINT or num_str) is negative (< 0)
1369 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1371 $x->{sign} =~ /^-/ ? 1 : 0; # -inf is also negative, but NaN not
1376 # return true when arg (BINT or num_str) is an integer
1377 # always true for BigInt, but different for BigFloats
1378 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1380 $x->{sign} =~ /^[+-]$/ ? 1 : 0; # inf/-inf/NaN aren't
1383 ###############################################################################
1387 # multiply two numbers -- stolen from Knuth Vol 2 pg 233
1388 # (BINT or num_str, BINT or num_str) return BINT
1391 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1392 # objectify is costly, so avoid it
1393 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1395 ($self,$x,$y,@r) = objectify(2,@_);
1398 return $x if $x->modify('bmul');
1400 return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1403 if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
1405 return $x->bnan() if $x->is_zero() || $y->is_zero();
1406 # result will always be +-inf:
1407 # +inf * +/+inf => +inf, -inf * -/-inf => +inf
1408 # +inf * -/-inf => -inf, -inf * +/+inf => -inf
1409 return $x->binf() if ($x->{sign} =~ /^\+/ && $y->{sign} =~ /^\+/);
1410 return $x->binf() if ($x->{sign} =~ /^-/ && $y->{sign} =~ /^-/);
1411 return $x->binf('-');
1414 return $upgrade->bmul($x,$upgrade->new($y),@r)
1415 if defined $upgrade && !$y->isa($self);
1417 $r[3] = $y; # no push here
1419 $x->{sign} = $x->{sign} eq $y->{sign} ? '+' : '-'; # +1 * +1 or -1 * -1 => +
1421 $x->{value} = $CALC->_mul($x->{value},$y->{value}); # do actual math
1422 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # no -0
1424 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1430 # helper function that handles +-inf cases for bdiv()/bmod() to reuse code
1431 my ($self,$x,$y) = @_;
1433 # NaN if x == NaN or y == NaN or x==y==0
1434 return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan()
1435 if (($x->is_nan() || $y->is_nan()) ||
1436 ($x->is_zero() && $y->is_zero()));
1438 # +-inf / +-inf == NaN, reminder also NaN
1439 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1441 return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan();
1443 # x / +-inf => 0, remainder x (works even if x == 0)
1444 if ($y->{sign} =~ /^[+-]inf$/)
1446 my $t = $x->copy(); # bzero clobbers up $x
1447 return wantarray ? ($x->bzero(),$t) : $x->bzero()
1450 # 5 / 0 => +inf, -6 / 0 => -inf
1451 # +inf / 0 = inf, inf, and -inf / 0 => -inf, -inf
1452 # exception: -8 / 0 has remainder -8, not 8
1453 # exception: -inf / 0 has remainder -inf, not inf
1456 # +-inf / 0 => special case for -inf
1457 return wantarray ? ($x,$x->copy()) : $x if $x->is_inf();
1458 if (!$x->is_zero() && !$x->is_inf())
1460 my $t = $x->copy(); # binf clobbers up $x
1462 ($x->binf($x->{sign}),$t) : $x->binf($x->{sign})
1466 # last case: +-inf / ordinary number
1468 $sign = '-inf' if substr($x->{sign},0,1) ne $y->{sign};
1470 return wantarray ? ($x,$self->bzero()) : $x;
1475 # (dividend: BINT or num_str, divisor: BINT or num_str) return
1476 # (BINT,BINT) (quo,rem) or BINT (only rem)
1479 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1480 # objectify is costly, so avoid it
1481 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1483 ($self,$x,$y,@r) = objectify(2,@_);
1486 return $x if $x->modify('bdiv');
1488 return $self->_div_inf($x,$y)
1489 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero());
1491 return $upgrade->bdiv($upgrade->new($x),$upgrade->new($y),@r)
1492 if defined $upgrade;
1494 $r[3] = $y; # no push!
1496 # calc new sign and in case $y == +/- 1, return $x
1497 my $xsign = $x->{sign}; # keep
1498 $x->{sign} = ($x->{sign} ne $y->{sign} ? '-' : '+');
1502 my $rem = $self->bzero();
1503 ($x->{value},$rem->{value}) = $CALC->_div($x->{value},$y->{value});
1504 $x->{sign} = '+' if $CALC->_is_zero($x->{value});
1505 $rem->{_a} = $x->{_a};
1506 $rem->{_p} = $x->{_p};
1507 $x->round(@r) if !exists $x->{_f} || ($x->{_f} & MB_NEVER_ROUND) == 0;
1508 if (! $CALC->_is_zero($rem->{value}))
1510 $rem->{sign} = $y->{sign};
1511 $rem = $y->copy()->bsub($rem) if $xsign ne $y->{sign}; # one of them '-'
1515 $rem->{sign} = '+'; # dont leave -0
1517 $rem->round(@r) if !exists $rem->{_f} || ($rem->{_f} & MB_NEVER_ROUND) == 0;
1521 $x->{value} = $CALC->_div($x->{value},$y->{value});
1522 $x->{sign} = '+' if $CALC->_is_zero($x->{value});
1524 $x->round(@r) if !exists $x->{_f} || ($x->{_f} & MB_NEVER_ROUND) == 0;
1528 ###############################################################################
1533 # modulus (or remainder)
1534 # (BINT or num_str, BINT or num_str) return BINT
1537 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1538 # objectify is costly, so avoid it
1539 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1541 ($self,$x,$y,@r) = objectify(2,@_);
1544 return $x if $x->modify('bmod');
1545 $r[3] = $y; # no push!
1546 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero())
1548 my ($d,$r) = $self->_div_inf($x,$y);
1549 $x->{sign} = $r->{sign};
1550 $x->{value} = $r->{value};
1551 return $x->round(@r);
1554 # calc new sign and in case $y == +/- 1, return $x
1555 $x->{value} = $CALC->_mod($x->{value},$y->{value});
1556 if (!$CALC->_is_zero($x->{value}))
1558 my $xsign = $x->{sign};
1559 $x->{sign} = $y->{sign};
1560 if ($xsign ne $y->{sign})
1562 my $t = $CALC->_copy($x->{value}); # copy $x
1563 $x->{value} = $CALC->_sub($y->{value},$t,1); # $y-$x
1568 $x->{sign} = '+'; # dont leave -0
1570 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1576 # Modular inverse. given a number which is (hopefully) relatively
1577 # prime to the modulus, calculate its inverse using Euclid's
1578 # alogrithm. If the number is not relatively prime to the modulus
1579 # (i.e. their gcd is not one) then NaN is returned.
1582 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1583 # objectify is costly, so avoid it
1584 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1586 ($self,$x,$y,@r) = objectify(2,@_);
1589 return $x if $x->modify('bmodinv');
1592 if ($y->{sign} ne '+' # -, NaN, +inf, -inf
1593 || $x->is_zero() # or num == 0
1594 || $x->{sign} !~ /^[+-]$/ # or num NaN, inf, -inf
1597 # put least residue into $x if $x was negative, and thus make it positive
1598 $x->bmod($y) if $x->{sign} eq '-';
1601 ($x->{value},$sign) = $CALC->_modinv($x->{value},$y->{value});
1602 return $x->bnan() if !defined $x->{value}; # in case no GCD found
1603 return $x if !defined $sign; # already real result
1604 $x->{sign} = $sign; # flip/flop see below
1605 $x->bmod($y); # calc real result
1611 # takes a very large number to a very large exponent in a given very
1612 # large modulus, quickly, thanks to binary exponentation. supports
1613 # negative exponents.
1614 my ($self,$num,$exp,$mod,@r) = objectify(3,@_);
1616 return $num if $num->modify('bmodpow');
1618 # check modulus for valid values
1619 return $num->bnan() if ($mod->{sign} ne '+' # NaN, - , -inf, +inf
1620 || $mod->is_zero());
1622 # check exponent for valid values
1623 if ($exp->{sign} =~ /\w/)
1625 # i.e., if it's NaN, +inf, or -inf...
1626 return $num->bnan();
1629 $num->bmodinv ($mod) if ($exp->{sign} eq '-');
1631 # check num for valid values (also NaN if there was no inverse but $exp < 0)
1632 return $num->bnan() if $num->{sign} !~ /^[+-]$/;
1634 # $mod is positive, sign on $exp is ignored, result also positive
1635 $num->{value} = $CALC->_modpow($num->{value},$exp->{value},$mod->{value});
1639 ###############################################################################
1643 # (BINT or num_str, BINT or num_str) return BINT
1644 # compute factorial number from $x, modify $x in place
1645 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1647 return $x if $x->modify('bfac');
1649 return $x if $x->{sign} eq '+inf'; # inf => inf
1650 return $x->bnan() if $x->{sign} ne '+'; # NaN, <0 etc => NaN
1652 $x->{value} = $CALC->_fac($x->{value});
1658 # (BINT or num_str, BINT or num_str) return BINT
1659 # compute power of two numbers -- stolen from Knuth Vol 2 pg 233
1660 # modifies first argument
1663 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1664 # objectify is costly, so avoid it
1665 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1667 ($self,$x,$y,@r) = objectify(2,@_);
1670 return $x if $x->modify('bpow');
1672 return $upgrade->bpow($upgrade->new($x),$y,@r)
1673 if defined $upgrade && !$y->isa($self);
1675 $r[3] = $y; # no push!
1676 return $x if $x->{sign} =~ /^[+-]inf$/; # -inf/+inf ** x
1677 return $x->bnan() if $x->{sign} eq $nan || $y->{sign} eq $nan;
1679 # cases 0 ** Y, X ** 0, X ** 1, 1 ** Y are handled by Calc or Emu
1682 $new_sign = $y->is_odd() ? '-' : '+' if ($x->{sign} ne '+');
1684 # 0 ** -7 => ( 1 / (0 ** 7)) => 1 / 0 => +inf
1686 if $y->{sign} eq '-' && $x->{sign} eq '+' && $CALC->_is_zero($x->{value});
1687 # 1 ** -y => 1 / (1 ** |y|)
1688 # so do test for negative $y after above's clause
1689 return $x->bnan() if $y->{sign} eq '-' && !$CALC->_is_one($x->{value});
1691 $x->{value} = $CALC->_pow($x->{value},$y->{value});
1692 $x->{sign} = $new_sign;
1693 $x->{sign} = '+' if $CALC->_is_zero($y->{value});
1694 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1700 # (BINT or num_str, BINT or num_str) return BINT
1701 # compute x << y, base n, y >= 0
1704 my ($self,$x,$y,$n,@r) = (ref($_[0]),@_);
1705 # objectify is costly, so avoid it
1706 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1708 ($self,$x,$y,$n,@r) = objectify(2,@_);
1711 return $x if $x->modify('blsft');
1712 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1713 return $x->round(@r) if $y->is_zero();
1715 $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
1717 $x->{value} = $CALC->_lsft($x->{value},$y->{value},$n);
1723 # (BINT or num_str, BINT or num_str) return BINT
1724 # compute x >> y, base n, y >= 0
1727 my ($self,$x,$y,$n,@r) = (ref($_[0]),@_);
1728 # objectify is costly, so avoid it
1729 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1731 ($self,$x,$y,$n,@r) = objectify(2,@_);
1734 return $x if $x->modify('brsft');
1735 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1736 return $x->round(@r) if $y->is_zero();
1737 return $x->bzero(@r) if $x->is_zero(); # 0 => 0
1739 $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
1741 # this only works for negative numbers when shifting in base 2
1742 if (($x->{sign} eq '-') && ($n == 2))
1744 return $x->round(@r) if $x->is_one('-'); # -1 => -1
1747 # although this is O(N*N) in calc (as_bin!) it is O(N) in Pari et al
1748 # but perhaps there is a better emulation for two's complement shift...
1749 # if $y != 1, we must simulate it by doing:
1750 # convert to bin, flip all bits, shift, and be done
1751 $x->binc(); # -3 => -2
1752 my $bin = $x->as_bin();
1753 $bin =~ s/^-0b//; # strip '-0b' prefix
1754 $bin =~ tr/10/01/; # flip bits
1756 if (CORE::length($bin) <= $y)
1758 $bin = '0'; # shifting to far right creates -1
1759 # 0, because later increment makes
1760 # that 1, attached '-' makes it '-1'
1761 # because -1 >> x == -1 !
1765 $bin =~ s/.{$y}$//; # cut off at the right side
1766 $bin = '1' . $bin; # extend left side by one dummy '1'
1767 $bin =~ tr/10/01/; # flip bits back
1769 my $res = $self->new('0b'.$bin); # add prefix and convert back
1770 $res->binc(); # remember to increment
1771 $x->{value} = $res->{value}; # take over value
1772 return $x->round(@r); # we are done now, magic, isn't?
1774 # x < 0, n == 2, y == 1
1775 $x->bdec(); # n == 2, but $y == 1: this fixes it
1778 $x->{value} = $CALC->_rsft($x->{value},$y->{value},$n);
1784 #(BINT or num_str, BINT or num_str) return BINT
1788 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1789 # objectify is costly, so avoid it
1790 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1792 ($self,$x,$y,@r) = objectify(2,@_);
1795 return $x if $x->modify('band');
1797 $r[3] = $y; # no push!
1799 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1801 my $sx = $x->{sign} eq '+' ? 1 : -1;
1802 my $sy = $y->{sign} eq '+' ? 1 : -1;
1804 if ($sx == 1 && $sy == 1)
1806 $x->{value} = $CALC->_and($x->{value},$y->{value});
1807 return $x->round(@r);
1810 if ($CAN{signed_and})
1812 $x->{value} = $CALC->_signed_and($x->{value},$y->{value},$sx,$sy);
1813 return $x->round(@r);
1817 __emu_band($self,$x,$y,$sx,$sy,@r);
1822 #(BINT or num_str, BINT or num_str) return BINT
1826 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1827 # objectify is costly, so avoid it
1828 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1830 ($self,$x,$y,@r) = objectify(2,@_);
1833 return $x if $x->modify('bior');
1834 $r[3] = $y; # no push!
1836 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1838 my $sx = $x->{sign} eq '+' ? 1 : -1;
1839 my $sy = $y->{sign} eq '+' ? 1 : -1;
1841 # the sign of X follows the sign of X, e.g. sign of Y irrelevant for bior()
1843 # don't use lib for negative values
1844 if ($sx == 1 && $sy == 1)
1846 $x->{value} = $CALC->_or($x->{value},$y->{value});
1847 return $x->round(@r);
1850 # if lib can do negative values, let it handle this
1851 if ($CAN{signed_or})
1853 $x->{value} = $CALC->_signed_or($x->{value},$y->{value},$sx,$sy);
1854 return $x->round(@r);
1858 __emu_bior($self,$x,$y,$sx,$sy,@r);
1863 #(BINT or num_str, BINT or num_str) return BINT
1867 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1868 # objectify is costly, so avoid it
1869 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1871 ($self,$x,$y,@r) = objectify(2,@_);
1874 return $x if $x->modify('bxor');
1875 $r[3] = $y; # no push!
1877 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1879 my $sx = $x->{sign} eq '+' ? 1 : -1;
1880 my $sy = $y->{sign} eq '+' ? 1 : -1;
1882 # don't use lib for negative values
1883 if ($sx == 1 && $sy == 1)
1885 $x->{value} = $CALC->_xor($x->{value},$y->{value});
1886 return $x->round(@r);
1889 # if lib can do negative values, let it handle this
1890 if ($CAN{signed_xor})
1892 $x->{value} = $CALC->_signed_xor($x->{value},$y->{value},$sx,$sy);
1893 return $x->round(@r);
1897 __emu_bxor($self,$x,$y,$sx,$sy,@r);
1902 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1904 my $e = $CALC->_len($x->{value});
1905 wantarray ? ($e,0) : $e;
1910 # return the nth decimal digit, negative values count backward, 0 is right
1911 my ($self,$x,$n) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1913 $n = $n->numify() if ref($n);
1914 $CALC->_digit($x->{value},$n||0);
1919 # return the amount of trailing zeros in $x (as scalar)
1921 $x = $class->new($x) unless ref $x;
1923 return 0 if $x->{sign} !~ /^[+-]$/; # NaN, inf, -inf etc
1925 $CALC->_zeros($x->{value}); # must handle odd values, 0 etc
1930 # calculate square root of $x
1931 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1933 return $x if $x->modify('bsqrt');
1935 return $x->bnan() if $x->{sign} !~ /^\+/; # -x or -inf or NaN => NaN
1936 return $x if $x->{sign} eq '+inf'; # sqrt(+inf) == inf
1938 return $upgrade->bsqrt($x,@r) if defined $upgrade;
1940 $x->{value} = $CALC->_sqrt($x->{value});
1946 # calculate $y'th root of $x
1949 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1951 $y = $self->new(2) unless defined $y;
1953 # objectify is costly, so avoid it
1954 if ((!ref($x)) || (ref($x) ne ref($y)))
1956 ($self,$x,$y,@r) = objectify(2,$self || $class,@_);
1959 return $x if $x->modify('broot');
1961 # NaN handling: $x ** 1/0, x or y NaN, or y inf/-inf or y == 0
1962 return $x->bnan() if $x->{sign} !~ /^\+/ || $y->is_zero() ||
1963 $y->{sign} !~ /^\+$/;
1965 return $x->round(@r)
1966 if $x->is_zero() || $x->is_one() || $x->is_inf() || $y->is_one();
1968 return $upgrade->new($x)->broot($upgrade->new($y),@r) if defined $upgrade;
1970 $x->{value} = $CALC->_root($x->{value},$y->{value});
1976 # return a copy of the exponent (here always 0, NaN or 1 for $m == 0)
1977 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
1979 if ($x->{sign} !~ /^[+-]$/)
1981 my $s = $x->{sign}; $s =~ s/^[+-]//; # NaN, -inf,+inf => NaN or inf
1982 return $self->new($s);
1984 return $self->bone() if $x->is_zero();
1986 $self->new($x->_trailing_zeros());
1991 # return the mantissa (compatible to Math::BigFloat, e.g. reduced)
1992 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
1994 if ($x->{sign} !~ /^[+-]$/)
1996 # for NaN, +inf, -inf: keep the sign
1997 return $self->new($x->{sign});
1999 my $m = $x->copy(); delete $m->{_p}; delete $m->{_a};
2000 # that's a bit inefficient:
2001 my $zeros = $m->_trailing_zeros();
2002 $m->brsft($zeros,10) if $zeros != 0;
2008 # return a copy of both the exponent and the mantissa
2009 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
2011 ($x->mantissa(),$x->exponent());
2014 ##############################################################################
2015 # rounding functions
2019 # precision: round to the $Nth digit left (+$n) or right (-$n) from the '.'
2020 # $n == 0 || $n == 1 => round to integer
2021 my $x = shift; my $self = ref($x) || $x; $x = $self->new($x) unless ref $x;
2023 my ($scale,$mode) = $x->_scale_p($x->precision(),$x->round_mode(),@_);
2025 return $x if !defined $scale || $x->modify('bfround'); # no-op
2027 # no-op for BigInts if $n <= 0
2028 $x->bround( $x->length()-$scale, $mode) if $scale > 0;
2030 delete $x->{_a}; # delete to save memory
2031 $x->{_p} = $scale; # store new _p
2035 sub _scan_for_nonzero
2037 # internal, used by bround()
2038 my ($x,$pad,$xs) = @_;
2040 my $len = $x->length();
2041 return 0 if $len == 1; # '5' is trailed by invisible zeros
2042 my $follow = $pad - 1;
2043 return 0 if $follow > $len || $follow < 1;
2045 # since we do not know underlying represention of $x, use decimal string
2046 my $r = substr ("$x",-$follow);
2047 $r =~ /[^0]/ ? 1 : 0;
2052 # Exists to make life easier for switch between MBF and MBI (should we
2053 # autoload fxxx() like MBF does for bxxx()?)
2060 # accuracy: +$n preserve $n digits from left,
2061 # -$n preserve $n digits from right (f.i. for 0.1234 style in MBF)
2063 # and overwrite the rest with 0's, return normalized number
2064 # do not return $x->bnorm(), but $x
2066 my $x = shift; $x = $class->new($x) unless ref $x;
2067 my ($scale,$mode) = $x->_scale_a($x->accuracy(),$x->round_mode(),@_);
2068 return $x if !defined $scale; # no-op
2069 return $x if $x->modify('bround');
2071 if ($x->is_zero() || $scale == 0)
2073 $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale; # 3 > 2
2076 return $x if $x->{sign} !~ /^[+-]$/; # inf, NaN
2078 # we have fewer digits than we want to scale to
2079 my $len = $x->length();
2080 # convert $scale to a scalar in case it is an object (put's a limit on the
2081 # number length, but this would already limited by memory constraints), makes
2083 $scale = $scale->numify() if ref ($scale);
2085 # scale < 0, but > -len (not >=!)
2086 if (($scale < 0 && $scale < -$len-1) || ($scale >= $len))
2088 $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale; # 3 > 2
2092 # count of 0's to pad, from left (+) or right (-): 9 - +6 => 3, or |-6| => 6
2093 my ($pad,$digit_round,$digit_after);
2094 $pad = $len - $scale;
2095 $pad = abs($scale-1) if $scale < 0;
2097 # do not use digit(), it is costly for binary => decimal
2099 my $xs = $CALC->_str($x->{value});
2102 # pad: 123: 0 => -1, at 1 => -2, at 2 => -3, at 3 => -4
2103 # pad+1: 123: 0 => 0, at 1 => -1, at 2 => -2, at 3 => -3
2104 $digit_round = '0'; $digit_round = substr($xs,$pl,1) if $pad <= $len;
2105 $pl++; $pl ++ if $pad >= $len;
2106 $digit_after = '0'; $digit_after = substr($xs,$pl,1) if $pad > 0;
2108 # in case of 01234 we round down, for 6789 up, and only in case 5 we look
2109 # closer at the remaining digits of the original $x, remember decision
2110 my $round_up = 1; # default round up
2112 ($mode eq 'trunc') || # trunc by round down
2113 ($digit_after =~ /[01234]/) || # round down anyway,
2115 ($digit_after eq '5') && # not 5000...0000
2116 ($x->_scan_for_nonzero($pad,$xs) == 0) &&
2118 ($mode eq 'even') && ($digit_round =~ /[24680]/) ||
2119 ($mode eq 'odd') && ($digit_round =~ /[13579]/) ||
2120 ($mode eq '+inf') && ($x->{sign} eq '-') ||
2121 ($mode eq '-inf') && ($x->{sign} eq '+') ||
2122 ($mode eq 'zero') # round down if zero, sign adjusted below
2124 my $put_back = 0; # not yet modified
2126 if (($pad > 0) && ($pad <= $len))
2128 substr($xs,-$pad,$pad) = '0' x $pad;
2133 $x->bzero(); # round to '0'
2136 if ($round_up) # what gave test above?
2139 $pad = $len, $xs = '0' x $pad if $scale < 0; # tlr: whack 0.51=>1.0
2141 # we modify directly the string variant instead of creating a number and
2142 # adding it, since that is faster (we already have the string)
2143 my $c = 0; $pad ++; # for $pad == $len case
2144 while ($pad <= $len)
2146 $c = substr($xs,-$pad,1) + 1; $c = '0' if $c eq '10';
2147 substr($xs,-$pad,1) = $c; $pad++;
2148 last if $c != 0; # no overflow => early out
2150 $xs = '1'.$xs if $c == 0;
2153 $x->{value} = $CALC->_new($xs) if $put_back == 1; # put back in if needed
2155 $x->{_a} = $scale if $scale >= 0;
2158 $x->{_a} = $len+$scale;
2159 $x->{_a} = 0 if $scale < -$len;
2166 # return integer less or equal then number; no-op since it's already integer
2167 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2174 # return integer greater or equal then number; no-op since it's already int
2175 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2182 # An object might be asked to return itself as bigint on certain overloaded
2183 # operations, this does exactly this, so that sub classes can simple inherit
2184 # it or override with their own integer conversion routine.
2190 # return as hex string, with prefixed 0x
2191 my $x = shift; $x = $class->new($x) if !ref($x);
2193 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2196 $s = $x->{sign} if $x->{sign} eq '-';
2197 $s . $CALC->_as_hex($x->{value});
2202 # return as binary string, with prefixed 0b
2203 my $x = shift; $x = $class->new($x) if !ref($x);
2205 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2207 my $s = ''; $s = $x->{sign} if $x->{sign} eq '-';
2208 return $s . $CALC->_as_bin($x->{value});
2211 ##############################################################################
2212 # private stuff (internal use only)
2216 # check for strings, if yes, return objects instead
2218 # the first argument is number of args objectify() should look at it will
2219 # return $count+1 elements, the first will be a classname. This is because
2220 # overloaded '""' calls bstr($object,undef,undef) and this would result in
2221 # useless objects beeing created and thrown away. So we cannot simple loop
2222 # over @_. If the given count is 0, all arguments will be used.
2224 # If the second arg is a ref, use it as class.
2225 # If not, try to use it as classname, unless undef, then use $class
2226 # (aka Math::BigInt). The latter shouldn't happen,though.
2229 # $x->badd(1); => ref x, scalar y
2230 # Class->badd(1,2); => classname x (scalar), scalar x, scalar y
2231 # Class->badd( Class->(1),2); => classname x (scalar), ref x, scalar y
2232 # Math::BigInt::badd(1,2); => scalar x, scalar y
2233 # In the last case we check number of arguments to turn it silently into
2234 # $class,1,2. (We can not take '1' as class ;o)
2235 # badd($class,1) is not supported (it should, eventually, try to add undef)
2236 # currently it tries 'Math::BigInt' + 1, which will not work.
2238 # some shortcut for the common cases
2240 return (ref($_[1]),$_[1]) if (@_ == 2) && ($_[0]||0 == 1) && ref($_[1]);
2242 my $count = abs(shift || 0);
2244 my (@a,$k,$d); # resulting array, temp, and downgrade
2247 # okay, got object as first
2252 # nope, got 1,2 (Class->xxx(1) => Class,1 and not supported)
2254 $a[0] = shift if $_[0] =~ /^[A-Z].*::/; # classname as first?
2258 # disable downgrading, because Math::BigFLoat->foo('1.0','2.0') needs floats
2259 if (defined ${"$a[0]::downgrade"})
2261 $d = ${"$a[0]::downgrade"};
2262 ${"$a[0]::downgrade"} = undef;
2265 my $up = ${"$a[0]::upgrade"};
2266 #print "Now in objectify, my class is today $a[0], count = $count\n";
2274 $k = $a[0]->new($k);
2276 elsif (!defined $up && ref($k) ne $a[0])
2278 # foreign object, try to convert to integer
2279 $k->can('as_number') ? $k = $k->as_number() : $k = $a[0]->new($k);
2292 $k = $a[0]->new($k);
2294 elsif (!defined $up && ref($k) ne $a[0])
2296 # foreign object, try to convert to integer
2297 $k->can('as_number') ? $k = $k->as_number() : $k = $a[0]->new($k);
2301 push @a,@_; # return other params, too
2305 require Carp; Carp::croak ("$class objectify needs list context");
2307 ${"$a[0]::downgrade"} = $d;
2315 $IMPORT++; # remember we did import()
2316 my @a; my $l = scalar @_;
2317 for ( my $i = 0; $i < $l ; $i++ )
2319 if ($_[$i] eq ':constant')
2321 # this causes overlord er load to step in
2323 integer => sub { $self->new(shift) },
2324 binary => sub { $self->new(shift) };
2326 elsif ($_[$i] eq 'upgrade')
2328 # this causes upgrading
2329 $upgrade = $_[$i+1]; # or undef to disable
2332 elsif ($_[$i] =~ /^lib$/i)
2334 # this causes a different low lib to take care...
2335 $CALC = $_[$i+1] || '';
2343 # any non :constant stuff is handled by our parent, Exporter
2344 # even if @_ is empty, to give it a chance
2345 $self->SUPER::import(@a); # need it for subclasses
2346 $self->export_to_level(1,$self,@a); # need it for MBF
2348 # try to load core math lib
2349 my @c = split /\s*,\s*/,$CALC;
2350 push @c,'Calc'; # if all fail, try this
2351 $CALC = ''; # signal error
2352 foreach my $lib (@c)
2354 next if ($lib || '') eq '';
2355 $lib = 'Math::BigInt::'.$lib if $lib !~ /^Math::BigInt/i;
2359 # Perl < 5.6.0 dies with "out of memory!" when eval() and ':constant' is
2360 # used in the same script, or eval inside import().
2361 my @parts = split /::/, $lib; # Math::BigInt => Math BigInt
2362 my $file = pop @parts; $file .= '.pm'; # BigInt => BigInt.pm
2364 $file = File::Spec->catfile (@parts, $file);
2365 eval { require "$file"; $lib->import( @c ); }
2369 eval "use $lib qw/@c/;";
2374 # loaded it ok, see if the api_version() is high enough
2375 if ($lib->can('api_version') && $lib->api_version() >= 1.0)
2378 # api_version matches, check if it really provides anything we need
2382 add mul div sub dec inc
2383 acmp len digit is_one is_zero is_even is_odd
2385 new copy check from_hex from_bin as_hex as_bin zeros
2386 rsft lsft xor and or
2387 mod sqrt root fac pow modinv modpow log_int gcd
2390 if (!$lib->can("_$method"))
2392 if (($WARN{$lib}||0) < 2)
2395 Carp::carp ("$lib is missing method '_$method'");
2396 $WARN{$lib} = 1; # still warn about the lib
2405 last; # found a usable one, break
2409 if (($WARN{$lib}||0) < 2)
2411 my $ver = eval "\$$lib\::VERSION";
2413 Carp::carp ("Cannot load outdated $lib v$ver, please upgrade");
2414 $WARN{$lib} = 2; # never warn again
2422 Carp::croak ("Couldn't load any math lib, not even 'Calc.pm'");
2424 _fill_can_cache(); # for emulating lower math lib functions
2429 # fill $CAN with the results of $CALC->can(...)
2432 for my $method (qw/ signed_and or signed_or xor signed_xor /)
2434 $CAN{$method} = $CALC->can("_$method") ? 1 : 0;
2440 # convert a (ref to) big hex string to BigInt, return undef for error
2443 my $x = Math::BigInt->bzero();
2446 $hs =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
2447 $hs =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
2449 return $x->bnan() if $hs !~ /^[\-\+]?0x[0-9A-Fa-f]+$/;
2451 my $sign = '+'; $sign = '-' if $hs =~ /^-/;
2453 $hs =~ s/^[+-]//; # strip sign
2454 $x->{value} = $CALC->_from_hex($hs);
2455 $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
2461 # convert a (ref to) big binary string to BigInt, return undef for error
2464 my $x = Math::BigInt->bzero();
2466 $bs =~ s/([01])_([01])/$1$2/g;
2467 $bs =~ s/([01])_([01])/$1$2/g;
2468 return $x->bnan() if $bs !~ /^[+-]?0b[01]+$/;
2470 my $sign = '+'; $sign = '-' if $bs =~ /^\-/;
2471 $bs =~ s/^[+-]//; # strip sign
2473 $x->{value} = $CALC->_from_bin($bs);
2474 $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
2480 # (ref to num_str) return num_str
2481 # internal, take apart a string and return the pieces
2482 # strip leading/trailing whitespace, leading zeros, underscore and reject
2486 # strip white space at front, also extranous leading zeros
2487 $x =~ s/^\s*([-]?)0*([0-9])/$1$2/g; # will not strip ' .2'
2488 $x =~ s/^\s+//; # but this will
2489 $x =~ s/\s+$//g; # strip white space at end
2491 # shortcut, if nothing to split, return early
2492 if ($x =~ /^[+-]?\d+\z/)
2494 $x =~ s/^([+-])0*([0-9])/$2/; my $sign = $1 || '+';
2495 return (\$sign, \$x, \'', \'', \0);
2498 # invalid starting char?
2499 return if $x !~ /^[+-]?(\.?[0-9]|0b[0-1]|0x[0-9a-fA-F])/;
2501 return __from_hex($x) if $x =~ /^[\-\+]?0x/; # hex string
2502 return __from_bin($x) if $x =~ /^[\-\+]?0b/; # binary string
2504 # strip underscores between digits
2505 $x =~ s/(\d)_(\d)/$1$2/g;
2506 $x =~ s/(\d)_(\d)/$1$2/g; # do twice for 1_2_3
2508 # some possible inputs:
2509 # 2.1234 # 0.12 # 1 # 1E1 # 2.134E1 # 434E-10 # 1.02009E-2
2510 # .2 # 1_2_3.4_5_6 # 1.4E1_2_3 # 1e3 # +.2 # 0e999
2512 my ($m,$e,$last) = split /[Ee]/,$x;
2513 return if defined $last; # last defined => 1e2E3 or others
2514 $e = '0' if !defined $e || $e eq "";
2516 # sign,value for exponent,mantint,mantfrac
2517 my ($es,$ev,$mis,$miv,$mfv);
2519 if ($e =~ /^([+-]?)0*(\d+)$/) # strip leading zeros
2523 return if $m eq '.' || $m eq '';
2524 my ($mi,$mf,$lastf) = split /\./,$m;
2525 return if defined $lastf; # lastf defined => 1.2.3 or others
2526 $mi = '0' if !defined $mi;
2527 $mi .= '0' if $mi =~ /^[\-\+]?$/;
2528 $mf = '0' if !defined $mf || $mf eq '';
2529 if ($mi =~ /^([+-]?)0*(\d+)$/) # strip leading zeros
2531 $mis = $1||'+'; $miv = $2;
2532 return unless ($mf =~ /^(\d*?)0*$/); # strip trailing zeros
2534 # handle the 0e999 case here
2535 $ev = 0 if $miv eq '0' && $mfv eq '';
2536 return (\$mis,\$miv,\$mfv,\$es,\$ev);
2539 return; # NaN, not a number
2542 ##############################################################################
2543 # internal calculation routines (others are in Math::BigInt::Calc etc)
2547 # (BINT or num_str, BINT or num_str) return BINT
2548 # does modify first argument
2551 my $x = shift; my $ty = shift;
2552 return $x->bnan() if ($x->{sign} eq $nan) || ($ty->{sign} eq $nan);
2553 $x * $ty / bgcd($x,$ty);
2556 ###############################################################################
2557 # this method return 0 if the object can be modified, or 1 for not
2558 # We use a fast constant sub() here, to avoid costly calls. Subclasses
2559 # may override it with special code (f.i. Math::BigInt::Constant does so)
2561 sub modify () { 0; }
2568 Math::BigInt - Arbitrary size integer math package
2574 # or make it faster: install (optional) Math::BigInt::GMP
2575 # and always use (it will fall back to pure Perl if the
2576 # GMP library is not installed):
2578 use Math::BigInt lib => 'GMP';
2580 my $str = '1234567890';
2581 my @values = (64,74,18);
2582 my $n = 1; my $sign = '-';
2585 $x = Math::BigInt->new($str); # defaults to 0
2586 $y = $x->copy(); # make a true copy
2587 $nan = Math::BigInt->bnan(); # create a NotANumber
2588 $zero = Math::BigInt->bzero(); # create a +0
2589 $inf = Math::BigInt->binf(); # create a +inf
2590 $inf = Math::BigInt->binf('-'); # create a -inf
2591 $one = Math::BigInt->bone(); # create a +1
2592 $one = Math::BigInt->bone('-'); # create a -1
2594 # Testing (don't modify their arguments)
2595 # (return true if the condition is met, otherwise false)
2597 $x->is_zero(); # if $x is +0
2598 $x->is_nan(); # if $x is NaN
2599 $x->is_one(); # if $x is +1
2600 $x->is_one('-'); # if $x is -1
2601 $x->is_odd(); # if $x is odd
2602 $x->is_even(); # if $x is even
2603 $x->is_pos(); # if $x >= 0
2604 $x->is_neg(); # if $x < 0
2605 $x->is_inf($sign); # if $x is +inf, or -inf (sign is default '+')
2606 $x->is_int(); # if $x is an integer (not a float)
2608 # comparing and digit/sign extration
2609 $x->bcmp($y); # compare numbers (undef,<0,=0,>0)
2610 $x->bacmp($y); # compare absolutely (undef,<0,=0,>0)
2611 $x->sign(); # return the sign, either +,- or NaN
2612 $x->digit($n); # return the nth digit, counting from right
2613 $x->digit(-$n); # return the nth digit, counting from left
2615 # The following all modify their first argument. If you want to preserve
2616 # $x, use $z = $x->copy()->bXXX($y); See under L<CAVEATS> for why this is
2617 # neccessary when mixing $a = $b assigments with non-overloaded math.
2619 $x->bzero(); # set $x to 0
2620 $x->bnan(); # set $x to NaN
2621 $x->bone(); # set $x to +1
2622 $x->bone('-'); # set $x to -1
2623 $x->binf(); # set $x to inf
2624 $x->binf('-'); # set $x to -inf
2626 $x->bneg(); # negation
2627 $x->babs(); # absolute value
2628 $x->bnorm(); # normalize (no-op in BigInt)
2629 $x->bnot(); # two's complement (bit wise not)
2630 $x->binc(); # increment $x by 1
2631 $x->bdec(); # decrement $x by 1
2633 $x->badd($y); # addition (add $y to $x)
2634 $x->bsub($y); # subtraction (subtract $y from $x)
2635 $x->bmul($y); # multiplication (multiply $x by $y)
2636 $x->bdiv($y); # divide, set $x to quotient
2637 # return (quo,rem) or quo if scalar
2639 $x->bmod($y); # modulus (x % y)
2640 $x->bmodpow($exp,$mod); # modular exponentation (($num**$exp) % $mod))
2641 $x->bmodinv($mod); # the inverse of $x in the given modulus $mod
2643 $x->bpow($y); # power of arguments (x ** y)
2644 $x->blsft($y); # left shift
2645 $x->brsft($y); # right shift
2646 $x->blsft($y,$n); # left shift, by base $n (like 10)
2647 $x->brsft($y,$n); # right shift, by base $n (like 10)
2649 $x->band($y); # bitwise and
2650 $x->bior($y); # bitwise inclusive or
2651 $x->bxor($y); # bitwise exclusive or
2652 $x->bnot(); # bitwise not (two's complement)
2654 $x->bsqrt(); # calculate square-root
2655 $x->broot($y); # $y'th root of $x (e.g. $y == 3 => cubic root)
2656 $x->bfac(); # factorial of $x (1*2*3*4*..$x)
2658 $x->round($A,$P,$mode); # round to accuracy or precision using mode $mode
2659 $x->bround($n); # accuracy: preserve $n digits
2660 $x->bfround($n); # round to $nth digit, no-op for BigInts
2662 # The following do not modify their arguments in BigInt (are no-ops),
2663 # but do so in BigFloat:
2665 $x->bfloor(); # return integer less or equal than $x
2666 $x->bceil(); # return integer greater or equal than $x
2668 # The following do not modify their arguments:
2670 # greatest common divisor (no OO style)
2671 my $gcd = Math::BigInt::bgcd(@values);
2672 # lowest common multiplicator (no OO style)
2673 my $lcm = Math::BigInt::blcm(@values);
2675 $x->length(); # return number of digits in number
2676 ($xl,$f) = $x->length(); # length of number and length of fraction part,
2677 # latter is always 0 digits long for BigInt's
2679 $x->exponent(); # return exponent as BigInt
2680 $x->mantissa(); # return (signed) mantissa as BigInt
2681 $x->parts(); # return (mantissa,exponent) as BigInt
2682 $x->copy(); # make a true copy of $x (unlike $y = $x;)
2683 $x->as_int(); # return as BigInt (in BigInt: same as copy())
2684 $x->numify(); # return as scalar (might overflow!)
2686 # conversation to string (do not modify their argument)
2687 $x->bstr(); # normalized string
2688 $x->bsstr(); # normalized string in scientific notation
2689 $x->as_hex(); # as signed hexadecimal string with prefixed 0x
2690 $x->as_bin(); # as signed binary string with prefixed 0b
2693 # precision and accuracy (see section about rounding for more)
2694 $x->precision(); # return P of $x (or global, if P of $x undef)
2695 $x->precision($n); # set P of $x to $n
2696 $x->accuracy(); # return A of $x (or global, if A of $x undef)
2697 $x->accuracy($n); # set A $x to $n
2700 Math::BigInt->precision(); # get/set global P for all BigInt objects
2701 Math::BigInt->accuracy(); # get/set global A for all BigInt objects
2702 Math::BigInt->config(); # return hash containing configuration
2706 All operators (inlcuding basic math operations) are overloaded if you
2707 declare your big integers as
2709 $i = new Math::BigInt '123_456_789_123_456_789';
2711 Operations with overloaded operators preserve the arguments which is
2712 exactly what you expect.
2718 Input values to these routines may be any string, that looks like a number
2719 and results in an integer, including hexadecimal and binary numbers.
2721 Scalars holding numbers may also be passed, but note that non-integer numbers
2722 may already have lost precision due to the conversation to float. Quote
2723 your input if you want BigInt to see all the digits:
2725 $x = Math::BigInt->new(12345678890123456789); # bad
2726 $x = Math::BigInt->new('12345678901234567890'); # good
2728 You can include one underscore between any two digits.
2730 This means integer values like 1.01E2 or even 1000E-2 are also accepted.
2731 Non-integer values result in NaN.
2733 Currently, Math::BigInt::new() defaults to 0, while Math::BigInt::new('')
2734 results in 'NaN'. This might change in the future, so use always the following
2735 explicit forms to get a zero or NaN:
2737 $zero = Math::BigInt->bzero();
2738 $nan = Math::BigInt->bnan();
2740 C<bnorm()> on a BigInt object is now effectively a no-op, since the numbers
2741 are always stored in normalized form. If passed a string, creates a BigInt
2742 object from the input.
2746 Output values are BigInt objects (normalized), except for bstr(), which
2747 returns a string in normalized form.
2748 Some routines (C<is_odd()>, C<is_even()>, C<is_zero()>, C<is_one()>,
2749 C<is_nan()>) return true or false, while others (C<bcmp()>, C<bacmp()>)
2750 return either undef, <0, 0 or >0 and are suited for sort.
2756 Each of the methods below (except config(), accuracy() and precision())
2757 accepts three additional parameters. These arguments $A, $P and $R are
2758 accuracy, precision and round_mode. Please see the section about
2759 L<ACCURACY and PRECISION> for more information.
2765 print Dumper ( Math::BigInt->config() );
2766 print Math::BigInt->config()->{lib},"\n";
2768 Returns a hash containing the configuration, e.g. the version number, lib
2769 loaded etc. The following hash keys are currently filled in with the
2770 appropriate information.
2774 ============================================================
2775 lib Name of the low-level math library
2777 lib_version Version of low-level math library (see 'lib')
2779 class The class name of config() you just called
2781 upgrade To which class math operations might be upgraded
2783 downgrade To which class math operations might be downgraded
2785 precision Global precision
2787 accuracy Global accuracy
2789 round_mode Global round mode
2791 version version number of the class you used
2793 div_scale Fallback acccuracy for div
2795 trap_nan If true, traps creation of NaN via croak()
2797 trap_inf If true, traps creation of +inf/-inf via croak()
2800 The following values can be set by passing C<config()> a reference to a hash:
2803 upgrade downgrade precision accuracy round_mode div_scale
2807 $new_cfg = Math::BigInt->config( { trap_inf => 1, precision => 5 } );
2811 $x->accuracy(5); # local for $x
2812 CLASS->accuracy(5); # global for all members of CLASS
2813 $A = $x->accuracy(); # read out
2814 $A = CLASS->accuracy(); # read out
2816 Set or get the global or local accuracy, aka how many significant digits the
2819 Please see the section about L<ACCURACY AND PRECISION> for further details.
2821 Value must be greater than zero. Pass an undef value to disable it:
2823 $x->accuracy(undef);
2824 Math::BigInt->accuracy(undef);
2826 Returns the current accuracy. For C<$x->accuracy()> it will return either the
2827 local accuracy, or if not defined, the global. This means the return value
2828 represents the accuracy that will be in effect for $x:
2830 $y = Math::BigInt->new(1234567); # unrounded
2831 print Math::BigInt->accuracy(4),"\n"; # set 4, print 4
2832 $x = Math::BigInt->new(123456); # will be automatically rounded
2833 print "$x $y\n"; # '123500 1234567'
2834 print $x->accuracy(),"\n"; # will be 4
2835 print $y->accuracy(),"\n"; # also 4, since global is 4
2836 print Math::BigInt->accuracy(5),"\n"; # set to 5, print 5
2837 print $x->accuracy(),"\n"; # still 4
2838 print $y->accuracy(),"\n"; # 5, since global is 5
2840 Note: Works also for subclasses like Math::BigFloat. Each class has it's own
2841 globals separated from Math::BigInt, but it is possible to subclass
2842 Math::BigInt and make the globals of the subclass aliases to the ones from
2847 $x->precision(-2); # local for $x, round right of the dot
2848 $x->precision(2); # ditto, but round left of the dot
2849 CLASS->accuracy(5); # global for all members of CLASS
2850 CLASS->precision(-5); # ditto
2851 $P = CLASS->precision(); # read out
2852 $P = $x->precision(); # read out
2854 Set or get the global or local precision, aka how many digits the result has
2855 after the dot (or where to round it when passing a positive number). In
2856 Math::BigInt, passing a negative number precision has no effect since no
2857 numbers have digits after the dot.
2859 Please see the section about L<ACCURACY AND PRECISION> for further details.
2861 Value must be greater than zero. Pass an undef value to disable it:
2863 $x->precision(undef);
2864 Math::BigInt->precision(undef);
2866 Returns the current precision. For C<$x->precision()> it will return either the
2867 local precision of $x, or if not defined, the global. This means the return
2868 value represents the accuracy that will be in effect for $x:
2870 $y = Math::BigInt->new(1234567); # unrounded
2871 print Math::BigInt->precision(4),"\n"; # set 4, print 4
2872 $x = Math::BigInt->new(123456); # will be automatically rounded
2874 Note: Works also for subclasses like Math::BigFloat. Each class has it's own
2875 globals separated from Math::BigInt, but it is possible to subclass
2876 Math::BigInt and make the globals of the subclass aliases to the ones from
2883 Shifts $x right by $y in base $n. Default is base 2, used are usually 10 and
2884 2, but others work, too.
2886 Right shifting usually amounts to dividing $x by $n ** $y and truncating the
2890 $x = Math::BigInt->new(10);
2891 $x->brsft(1); # same as $x >> 1: 5
2892 $x = Math::BigInt->new(1234);
2893 $x->brsft(2,10); # result 12
2895 There is one exception, and that is base 2 with negative $x:
2898 $x = Math::BigInt->new(-5);
2901 This will print -3, not -2 (as it would if you divide -5 by 2 and truncate the
2906 $x = Math::BigInt->new($str,$A,$P,$R);
2908 Creates a new BigInt object from a scalar or another BigInt object. The
2909 input is accepted as decimal, hex (with leading '0x') or binary (with leading
2912 See L<Input> for more info on accepted input formats.
2916 $x = Math::BigInt->bnan();
2918 Creates a new BigInt object representing NaN (Not A Number).
2919 If used on an object, it will set it to NaN:
2925 $x = Math::BigInt->bzero();
2927 Creates a new BigInt object representing zero.
2928 If used on an object, it will set it to zero:
2934 $x = Math::BigInt->binf($sign);
2936 Creates a new BigInt object representing infinity. The optional argument is
2937 either '-' or '+', indicating whether you want infinity or minus infinity.
2938 If used on an object, it will set it to infinity:
2945 $x = Math::BigInt->binf($sign);
2947 Creates a new BigInt object representing one. The optional argument is
2948 either '-' or '+', indicating whether you want one or minus one.
2949 If used on an object, it will set it to one:
2954 =head2 is_one()/is_zero()/is_nan()/is_inf()
2957 $x->is_zero(); # true if arg is +0
2958 $x->is_nan(); # true if arg is NaN
2959 $x->is_one(); # true if arg is +1
2960 $x->is_one('-'); # true if arg is -1
2961 $x->is_inf(); # true if +inf
2962 $x->is_inf('-'); # true if -inf (sign is default '+')
2964 These methods all test the BigInt for beeing one specific value and return
2965 true or false depending on the input. These are faster than doing something
2970 =head2 is_pos()/is_neg()
2972 $x->is_pos(); # true if >= 0
2973 $x->is_neg(); # true if < 0
2975 The methods return true if the argument is positive or negative, respectively.
2976 C<NaN> is neither positive nor negative, while C<+inf> counts as positive, and
2977 C<-inf> is negative. A C<zero> is positive.
2979 These methods are only testing the sign, and not the value.
2981 C<is_positive()> and C<is_negative()> are aliase to C<is_pos()> and
2982 C<is_neg()>, respectively. C<is_positive()> and C<is_negative()> were
2983 introduced in v1.36, while C<is_pos()> and C<is_neg()> were only introduced
2986 =head2 is_odd()/is_even()/is_int()
2988 $x->is_odd(); # true if odd, false for even
2989 $x->is_even(); # true if even, false for odd
2990 $x->is_int(); # true if $x is an integer
2992 The return true when the argument satisfies the condition. C<NaN>, C<+inf>,
2993 C<-inf> are not integers and are neither odd nor even.
2995 In BigInt, all numbers except C<NaN>, C<+inf> and C<-inf> are integers.
3001 Compares $x with $y and takes the sign into account.
3002 Returns -1, 0, 1 or undef.
3008 Compares $x with $y while ignoring their. Returns -1, 0, 1 or undef.
3014 Return the sign, of $x, meaning either C<+>, C<->, C<-inf>, C<+inf> or NaN.
3018 $x->digit($n); # return the nth digit, counting from right
3020 If C<$n> is negative, returns the digit counting from left.
3026 Negate the number, e.g. change the sign between '+' and '-', or between '+inf'
3027 and '-inf', respectively. Does nothing for NaN or zero.
3033 Set the number to it's absolute value, e.g. change the sign from '-' to '+'
3034 and from '-inf' to '+inf', respectively. Does nothing for NaN or positive
3039 $x->bnorm(); # normalize (no-op)
3045 Two's complement (bit wise not). This is equivalent to
3053 $x->binc(); # increment x by 1
3057 $x->bdec(); # decrement x by 1
3061 $x->badd($y); # addition (add $y to $x)
3065 $x->bsub($y); # subtraction (subtract $y from $x)
3069 $x->bmul($y); # multiplication (multiply $x by $y)
3073 $x->bdiv($y); # divide, set $x to quotient
3074 # return (quo,rem) or quo if scalar
3078 $x->bmod($y); # modulus (x % y)
3082 num->bmodinv($mod); # modular inverse
3084 Returns the inverse of C<$num> in the given modulus C<$mod>. 'C<NaN>' is
3085 returned unless C<$num> is relatively prime to C<$mod>, i.e. unless
3086 C<bgcd($num, $mod)==1>.
3090 $num->bmodpow($exp,$mod); # modular exponentation
3091 # ($num**$exp % $mod)
3093 Returns the value of C<$num> taken to the power C<$exp> in the modulus
3094 C<$mod> using binary exponentation. C<bmodpow> is far superior to
3099 because it is much faster - it reduces internal variables into
3100 the modulus whenever possible, so it operates on smaller numbers.
3102 C<bmodpow> also supports negative exponents.
3104 bmodpow($num, -1, $mod)
3106 is exactly equivalent to
3112 $x->bpow($y); # power of arguments (x ** y)
3116 $x->blsft($y); # left shift
3117 $x->blsft($y,$n); # left shift, in base $n (like 10)
3121 $x->brsft($y); # right shift
3122 $x->brsft($y,$n); # right shift, in base $n (like 10)
3126 $x->band($y); # bitwise and
3130 $x->bior($y); # bitwise inclusive or
3134 $x->bxor($y); # bitwise exclusive or
3138 $x->bnot(); # bitwise not (two's complement)
3142 $x->bsqrt(); # calculate square-root
3146 $x->bfac(); # factorial of $x (1*2*3*4*..$x)
3150 $x->round($A,$P,$round_mode);
3152 Round $x to accuracy C<$A> or precision C<$P> using the round mode
3157 $x->bround($N); # accuracy: preserve $N digits
3161 $x->bfround($N); # round to $Nth digit, no-op for BigInts
3167 Set $x to the integer less or equal than $x. This is a no-op in BigInt, but
3168 does change $x in BigFloat.
3174 Set $x to the integer greater or equal than $x. This is a no-op in BigInt, but
3175 does change $x in BigFloat.
3179 bgcd(@values); # greatest common divisor (no OO style)
3183 blcm(@values); # lowest common multiplicator (no OO style)
3188 ($xl,$fl) = $x->length();
3190 Returns the number of digits in the decimal representation of the number.
3191 In list context, returns the length of the integer and fraction part. For
3192 BigInt's, the length of the fraction part will always be 0.
3198 Return the exponent of $x as BigInt.
3204 Return the signed mantissa of $x as BigInt.
3208 $x->parts(); # return (mantissa,exponent) as BigInt
3212 $x->copy(); # make a true copy of $x (unlike $y = $x;)
3218 Returns $x as a BigInt (truncated towards zero). In BigInt this is the same as
3221 C<as_number()> is an alias to this method. C<as_number> was introduced in
3222 v1.22, while C<as_int()> was only introduced in v1.68.
3228 Returns a normalized string represantation of C<$x>.
3232 $x->bsstr(); # normalized string in scientific notation
3236 $x->as_hex(); # as signed hexadecimal string with prefixed 0x
3240 $x->as_bin(); # as signed binary string with prefixed 0b
3242 =head1 ACCURACY and PRECISION
3244 Since version v1.33, Math::BigInt and Math::BigFloat have full support for
3245 accuracy and precision based rounding, both automatically after every
3246 operation, as well as manually.
3248 This section describes the accuracy/precision handling in Math::Big* as it
3249 used to be and as it is now, complete with an explanation of all terms and
3252 Not yet implemented things (but with correct description) are marked with '!',
3253 things that need to be answered are marked with '?'.
3255 In the next paragraph follows a short description of terms used here (because
3256 these may differ from terms used by others people or documentation).
3258 During the rest of this document, the shortcuts A (for accuracy), P (for
3259 precision), F (fallback) and R (rounding mode) will be used.
3263 A fixed number of digits before (positive) or after (negative)
3264 the decimal point. For example, 123.45 has a precision of -2. 0 means an
3265 integer like 123 (or 120). A precision of 2 means two digits to the left
3266 of the decimal point are zero, so 123 with P = 1 becomes 120. Note that
3267 numbers with zeros before the decimal point may have different precisions,
3268 because 1200 can have p = 0, 1 or 2 (depending on what the inital value
3269 was). It could also have p < 0, when the digits after the decimal point
3272 The string output (of floating point numbers) will be padded with zeros:
3274 Initial value P A Result String
3275 ------------------------------------------------------------
3276 1234.01 -3 1000 1000
3279 1234.001 1 1234 1234.0
3281 1234.01 2 1234.01 1234.01
3282 1234.01 5 1234.01 1234.01000
3284 For BigInts, no padding occurs.
3288 Number of significant digits. Leading zeros are not counted. A
3289 number may have an accuracy greater than the non-zero digits
3290 when there are zeros in it or trailing zeros. For example, 123.456 has
3291 A of 6, 10203 has 5, 123.0506 has 7, 123.450000 has 8 and 0.000123 has 3.
3293 The string output (of floating point numbers) will be padded with zeros:
3295 Initial value P A Result String
3296 ------------------------------------------------------------
3298 1234.01 6 1234.01 1234.01
3299 1234.1 8 1234.1 1234.1000
3301 For BigInts, no padding occurs.
3305 When both A and P are undefined, this is used as a fallback accuracy when
3308 =head2 Rounding mode R
3310 When rounding a number, different 'styles' or 'kinds'
3311 of rounding are possible. (Note that random rounding, as in
3312 Math::Round, is not implemented.)
3318 truncation invariably removes all digits following the
3319 rounding place, replacing them with zeros. Thus, 987.65 rounded
3320 to tens (P=1) becomes 980, and rounded to the fourth sigdig
3321 becomes 987.6 (A=4). 123.456 rounded to the second place after the
3322 decimal point (P=-2) becomes 123.46.
3324 All other implemented styles of rounding attempt to round to the
3325 "nearest digit." If the digit D immediately to the right of the
3326 rounding place (skipping the decimal point) is greater than 5, the
3327 number is incremented at the rounding place (possibly causing a
3328 cascade of incrementation): e.g. when rounding to units, 0.9 rounds
3329 to 1, and -19.9 rounds to -20. If D < 5, the number is similarly
3330 truncated at the rounding place: e.g. when rounding to units, 0.4
3331 rounds to 0, and -19.4 rounds to -19.
3333 However the results of other styles of rounding differ if the
3334 digit immediately to the right of the rounding place (skipping the
3335 decimal point) is 5 and if there are no digits, or no digits other
3336 than 0, after that 5. In such cases:
3340 rounds the digit at the rounding place to 0, 2, 4, 6, or 8
3341 if it is not already. E.g., when rounding to the first sigdig, 0.45
3342 becomes 0.4, -0.55 becomes -0.6, but 0.4501 becomes 0.5.
3346 rounds the digit at the rounding place to 1, 3, 5, 7, or 9 if
3347 it is not already. E.g., when rounding to the first sigdig, 0.45
3348 becomes 0.5, -0.55 becomes -0.5, but 0.5501 becomes 0.6.
3352 round to plus infinity, i.e. always round up. E.g., when
3353 rounding to the first sigdig, 0.45 becomes 0.5, -0.55 becomes -0.5,
3354 and 0.4501 also becomes 0.5.
3358 round to minus infinity, i.e. always round down. E.g., when
3359 rounding to the first sigdig, 0.45 becomes 0.4, -0.55 becomes -0.6,
3360 but 0.4501 becomes 0.5.
3364 round to zero, i.e. positive numbers down, negative ones up.
3365 E.g., when rounding to the first sigdig, 0.45 becomes 0.4, -0.55
3366 becomes -0.5, but 0.4501 becomes 0.5.
3370 The handling of A & P in MBI/MBF (the old core code shipped with Perl
3371 versions <= 5.7.2) is like this:
3377 * ffround($p) is able to round to $p number of digits after the decimal
3379 * otherwise P is unused
3381 =item Accuracy (significant digits)
3383 * fround($a) rounds to $a significant digits
3384 * only fdiv() and fsqrt() take A as (optional) paramater
3385 + other operations simply create the same number (fneg etc), or more (fmul)
3387 + rounding/truncating is only done when explicitly calling one of fround
3388 or ffround, and never for BigInt (not implemented)
3389 * fsqrt() simply hands its accuracy argument over to fdiv.
3390 * the documentation and the comment in the code indicate two different ways
3391 on how fdiv() determines the maximum number of digits it should calculate,
3392 and the actual code does yet another thing
3394 max($Math::BigFloat::div_scale,length(dividend)+length(divisor))
3396 result has at most max(scale, length(dividend), length(divisor)) digits
3398 scale = max(scale, length(dividend)-1,length(divisor)-1);
3399 scale += length(divisior) - length(dividend);
3400 So for lx = 3, ly = 9, scale = 10, scale will actually be 16 (10+9-3).
3401 Actually, the 'difference' added to the scale is calculated from the
3402 number of "significant digits" in dividend and divisor, which is derived
3403 by looking at the length of the mantissa. Which is wrong, since it includes
3404 the + sign (oops) and actually gets 2 for '+100' and 4 for '+101'. Oops
3405 again. Thus 124/3 with div_scale=1 will get you '41.3' based on the strange
3406 assumption that 124 has 3 significant digits, while 120/7 will get you
3407 '17', not '17.1' since 120 is thought to have 2 significant digits.
3408 The rounding after the division then uses the remainder and $y to determine
3409 wether it must round up or down.
3410 ? I have no idea which is the right way. That's why I used a slightly more
3411 ? simple scheme and tweaked the few failing testcases to match it.
3415 This is how it works now:
3419 =item Setting/Accessing
3421 * You can set the A global via C<< Math::BigInt->accuracy() >> or
3422 C<< Math::BigFloat->accuracy() >> or whatever class you are using.
3423 * You can also set P globally by using C<< Math::SomeClass->precision() >>
3425 * Globals are classwide, and not inherited by subclasses.
3426 * to undefine A, use C<< Math::SomeCLass->accuracy(undef); >>
3427 * to undefine P, use C<< Math::SomeClass->precision(undef); >>
3428 * Setting C<< Math::SomeClass->accuracy() >> clears automatically
3429 C<< Math::SomeClass->precision() >>, and vice versa.
3430 * To be valid, A must be > 0, P can have any value.
3431 * If P is negative, this means round to the P'th place to the right of the
3432 decimal point; positive values mean to the left of the decimal point.
3433 P of 0 means round to integer.
3434 * to find out the current global A, use C<< Math::SomeClass->accuracy() >>
3435 * to find out the current global P, use C<< Math::SomeClass->precision() >>
3436 * use C<< $x->accuracy() >> respective C<< $x->precision() >> for the local
3437 setting of C<< $x >>.
3438 * Please note that C<< $x->accuracy() >> respecive C<< $x->precision() >>
3439 return eventually defined global A or P, when C<< $x >>'s A or P is not
3442 =item Creating numbers
3444 * When you create a number, you can give it's desired A or P via:
3445 $x = Math::BigInt->new($number,$A,$P);
3446 * Only one of A or P can be defined, otherwise the result is NaN
3447 * If no A or P is give ($x = Math::BigInt->new($number) form), then the
3448 globals (if set) will be used. Thus changing the global defaults later on
3449 will not change the A or P of previously created numbers (i.e., A and P of
3450 $x will be what was in effect when $x was created)
3451 * If given undef for A and P, B<no> rounding will occur, and the globals will
3452 B<not> be used. This is used by subclasses to create numbers without
3453 suffering rounding in the parent. Thus a subclass is able to have it's own
3454 globals enforced upon creation of a number by using
3455 C<< $x = Math::BigInt->new($number,undef,undef) >>:
3457 use Math::BigInt::SomeSubclass;
3460 Math::BigInt->accuracy(2);
3461 Math::BigInt::SomeSubClass->accuracy(3);
3462 $x = Math::BigInt::SomeSubClass->new(1234);
3464 $x is now 1230, and not 1200. A subclass might choose to implement
3465 this otherwise, e.g. falling back to the parent's A and P.
3469 * If A or P are enabled/defined, they are used to round the result of each
3470 operation according to the rules below
3471 * Negative P is ignored in Math::BigInt, since BigInts never have digits
3472 after the decimal point
3473 * Math::BigFloat uses Math::BigInt internally, but setting A or P inside
3474 Math::BigInt as globals does not tamper with the parts of a BigFloat.
3475 A flag is used to mark all Math::BigFloat numbers as 'never round'.
3479 * It only makes sense that a number has only one of A or P at a time.
3480 If you set either A or P on one object, or globally, the other one will
3481 be automatically cleared.
3482 * If two objects are involved in an operation, and one of them has A in
3483 effect, and the other P, this results in an error (NaN).
3484 * A takes precendence over P (Hint: A comes before P).
3485 If neither of them is defined, nothing is used, i.e. the result will have
3486 as many digits as it can (with an exception for fdiv/fsqrt) and will not
3488 * There is another setting for fdiv() (and thus for fsqrt()). If neither of
3489 A or P is defined, fdiv() will use a fallback (F) of $div_scale digits.
3490 If either the dividend's or the divisor's mantissa has more digits than
3491 the value of F, the higher value will be used instead of F.
3492 This is to limit the digits (A) of the result (just consider what would
3493 happen with unlimited A and P in the case of 1/3 :-)
3494 * fdiv will calculate (at least) 4 more digits than required (determined by
3495 A, P or F), and, if F is not used, round the result
3496 (this will still fail in the case of a result like 0.12345000000001 with A
3497 or P of 5, but this can not be helped - or can it?)
3498 * Thus you can have the math done by on Math::Big* class in two modi:
3499 + never round (this is the default):
3500 This is done by setting A and P to undef. No math operation
3501 will round the result, with fdiv() and fsqrt() as exceptions to guard
3502 against overflows. You must explicitely call bround(), bfround() or
3503 round() (the latter with parameters).
3504 Note: Once you have rounded a number, the settings will 'stick' on it
3505 and 'infect' all other numbers engaged in math operations with it, since
3506 local settings have the highest precedence. So, to get SaferRound[tm],
3507 use a copy() before rounding like this:
3509 $x = Math::BigFloat->new(12.34);
3510 $y = Math::BigFloat->new(98.76);
3511 $z = $x * $y; # 1218.6984
3512 print $x->copy()->fround(3); # 12.3 (but A is now 3!)
3513 $z = $x * $y; # still 1218.6984, without
3514 # copy would have been 1210!
3516 + round after each op:
3517 After each single operation (except for testing like is_zero()), the
3518 method round() is called and the result is rounded appropriately. By
3519 setting proper values for A and P, you can have all-the-same-A or
3520 all-the-same-P modes. For example, Math::Currency might set A to undef,
3521 and P to -2, globally.
3523 ?Maybe an extra option that forbids local A & P settings would be in order,
3524 ?so that intermediate rounding does not 'poison' further math?
3526 =item Overriding globals
3528 * you will be able to give A, P and R as an argument to all the calculation
3529 routines; the second parameter is A, the third one is P, and the fourth is
3530 R (shift right by one for binary operations like badd). P is used only if
3531 the first parameter (A) is undefined. These three parameters override the
3532 globals in the order detailed as follows, i.e. the first defined value
3534 (local: per object, global: global default, parameter: argument to sub)
3537 + local A (if defined on both of the operands: smaller one is taken)
3538 + local P (if defined on both of the operands: bigger one is taken)
3542 * fsqrt() will hand its arguments to fdiv(), as it used to, only now for two
3543 arguments (A and P) instead of one
3545 =item Local settings
3547 * You can set A or P locally by using C<< $x->accuracy() >> or
3548 C<< $x->precision() >>
3549 and thus force different A and P for different objects/numbers.
3550 * Setting A or P this way immediately rounds $x to the new value.
3551 * C<< $x->accuracy() >> clears C<< $x->precision() >>, and vice versa.
3555 * the rounding routines will use the respective global or local settings.
3556 fround()/bround() is for accuracy rounding, while ffround()/bfround()
3558 * the two rounding functions take as the second parameter one of the
3559 following rounding modes (R):
3560 'even', 'odd', '+inf', '-inf', 'zero', 'trunc'
3561 * you can set/get the global R by using C<< Math::SomeClass->round_mode() >>
3562 or by setting C<< $Math::SomeClass::round_mode >>
3563 * after each operation, C<< $result->round() >> is called, and the result may
3564 eventually be rounded (that is, if A or P were set either locally,
3565 globally or as parameter to the operation)
3566 * to manually round a number, call C<< $x->round($A,$P,$round_mode); >>
3567 this will round the number by using the appropriate rounding function
3568 and then normalize it.
3569 * rounding modifies the local settings of the number:
3571 $x = Math::BigFloat->new(123.456);
3575 Here 4 takes precedence over 5, so 123.5 is the result and $x->accuracy()
3576 will be 4 from now on.
3578 =item Default values
3587 * The defaults are set up so that the new code gives the same results as
3588 the old code (except in a few cases on fdiv):
3589 + Both A and P are undefined and thus will not be used for rounding
3590 after each operation.
3591 + round() is thus a no-op, unless given extra parameters A and P
3597 The actual numbers are stored as unsigned big integers (with seperate sign).
3598 You should neither care about nor depend on the internal representation; it
3599 might change without notice. Use only method calls like C<< $x->sign(); >>
3600 instead relying on the internal hash keys like in C<< $x->{sign}; >>.
3604 Math with the numbers is done (by default) by a module called
3605 C<Math::BigInt::Calc>. This is equivalent to saying:
3607 use Math::BigInt lib => 'Calc';
3609 You can change this by using:
3611 use Math::BigInt lib => 'BitVect';
3613 The following would first try to find Math::BigInt::Foo, then
3614 Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
3616 use Math::BigInt lib => 'Foo,Math::BigInt::Bar';
3618 Since Math::BigInt::GMP is in almost all cases faster than Calc (especially in
3619 cases involving really big numbers, where it is B<much> faster), and there is
3620 no penalty if Math::BigInt::GMP is not installed, it is a good idea to always
3623 use Math::BigInt lib => 'GMP';
3625 Different low-level libraries use different formats to store the
3626 numbers. You should not depend on the number having a specific format.
3628 See the respective math library module documentation for further details.
3632 The sign is either '+', '-', 'NaN', '+inf' or '-inf' and stored seperately.
3634 A sign of 'NaN' is used to represent the result when input arguments are not
3635 numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively
3636 minus infinity. You will get '+inf' when dividing a positive number by 0, and
3637 '-inf' when dividing any negative number by 0.
3639 =head2 mantissa(), exponent() and parts()
3641 C<mantissa()> and C<exponent()> return the said parts of the BigInt such
3644 $m = $x->mantissa();
3645 $e = $x->exponent();
3646 $y = $m * ( 10 ** $e );
3647 print "ok\n" if $x == $y;
3649 C<< ($m,$e) = $x->parts() >> is just a shortcut that gives you both of them
3650 in one go. Both the returned mantissa and exponent have a sign.
3652 Currently, for BigInts C<$e> is always 0, except for NaN, +inf and -inf,
3653 where it is C<NaN>; and for C<$x == 0>, where it is C<1> (to be compatible
3654 with Math::BigFloat's internal representation of a zero as C<0E1>).
3656 C<$m> is currently just a copy of the original number. The relation between
3657 C<$e> and C<$m> will stay always the same, though their real values might
3664 sub bint { Math::BigInt->new(shift); }
3666 $x = Math::BigInt->bstr("1234") # string "1234"
3667 $x = "$x"; # same as bstr()
3668 $x = Math::BigInt->bneg("1234"); # BigInt "-1234"
3669 $x = Math::BigInt->babs("-12345"); # BigInt "12345"
3670 $x = Math::BigInt->bnorm("-0 00"); # BigInt "0"
3671 $x = bint(1) + bint(2); # BigInt "3"
3672 $x = bint(1) + "2"; # ditto (auto-BigIntify of "2")
3673 $x = bint(1); # BigInt "1"
3674 $x = $x + 5 / 2; # BigInt "3"
3675 $x = $x ** 3; # BigInt "27"
3676 $x *= 2; # BigInt "54"
3677 $x = Math::BigInt->new(0); # BigInt "0"
3679 $x = Math::BigInt->badd(4,5) # BigInt "9"
3680 print $x->bsstr(); # 9e+0
3682 Examples for rounding:
3687 $x = Math::BigFloat->new(123.4567);
3688 $y = Math::BigFloat->new(123.456789);
3689 Math::BigFloat->accuracy(4); # no more A than 4
3691 ok ($x->copy()->fround(),123.4); # even rounding
3692 print $x->copy()->fround(),"\n"; # 123.4
3693 Math::BigFloat->round_mode('odd'); # round to odd
3694 print $x->copy()->fround(),"\n"; # 123.5
3695 Math::BigFloat->accuracy(5); # no more A than 5
3696 Math::BigFloat->round_mode('odd'); # round to odd
3697 print $x->copy()->fround(),"\n"; # 123.46
3698 $y = $x->copy()->fround(4),"\n"; # A = 4: 123.4
3699 print "$y, ",$y->accuracy(),"\n"; # 123.4, 4
3701 Math::BigFloat->accuracy(undef); # A not important now
3702 Math::BigFloat->precision(2); # P important
3703 print $x->copy()->bnorm(),"\n"; # 123.46
3704 print $x->copy()->fround(),"\n"; # 123.46
3706 Examples for converting:
3708 my $x = Math::BigInt->new('0b1'.'01' x 123);
3709 print "bin: ",$x->as_bin()," hex:",$x->as_hex()," dec: ",$x,"\n";
3711 =head1 Autocreating constants
3713 After C<use Math::BigInt ':constant'> all the B<integer> decimal, hexadecimal
3714 and binary constants in the given scope are converted to C<Math::BigInt>.
3715 This conversion happens at compile time.
3719 perl -MMath::BigInt=:constant -e 'print 2**100,"\n"'
3721 prints the integer value of C<2**100>. Note that without conversion of
3722 constants the expression 2**100 will be calculated as perl scalar.
3724 Please note that strings and floating point constants are not affected,
3727 use Math::BigInt qw/:constant/;
3729 $x = 1234567890123456789012345678901234567890
3730 + 123456789123456789;
3731 $y = '1234567890123456789012345678901234567890'
3732 + '123456789123456789';
3734 do not work. You need an explicit Math::BigInt->new() around one of the
3735 operands. You should also quote large constants to protect loss of precision:
3739 $x = Math::BigInt->new('1234567889123456789123456789123456789');
3741 Without the quotes Perl would convert the large number to a floating point
3742 constant at compile time and then hand the result to BigInt, which results in
3743 an truncated result or a NaN.
3745 This also applies to integers that look like floating point constants:
3747 use Math::BigInt ':constant';
3749 print ref(123e2),"\n";
3750 print ref(123.2e2),"\n";
3752 will print nothing but newlines. Use either L<bignum> or L<Math::BigFloat>
3753 to get this to work.
3757 Using the form $x += $y; etc over $x = $x + $y is faster, since a copy of $x
3758 must be made in the second case. For long numbers, the copy can eat up to 20%
3759 of the work (in the case of addition/subtraction, less for
3760 multiplication/division). If $y is very small compared to $x, the form
3761 $x += $y is MUCH faster than $x = $x + $y since making the copy of $x takes
3762 more time then the actual addition.
3764 With a technique called copy-on-write, the cost of copying with overload could
3765 be minimized or even completely avoided. A test implementation of COW did show
3766 performance gains for overloaded math, but introduced a performance loss due
3767 to a constant overhead for all other operatons. So Math::BigInt does currently
3770 The rewritten version of this module (vs. v0.01) is slower on certain
3771 operations, like C<new()>, C<bstr()> and C<numify()>. The reason are that it
3772 does now more work and handles much more cases. The time spent in these
3773 operations is usually gained in the other math operations so that code on
3774 the average should get (much) faster. If they don't, please contact the author.
3776 Some operations may be slower for small numbers, but are significantly faster
3777 for big numbers. Other operations are now constant (O(1), like C<bneg()>,
3778 C<babs()> etc), instead of O(N) and thus nearly always take much less time.
3779 These optimizations were done on purpose.
3781 If you find the Calc module to slow, try to install any of the replacement
3782 modules and see if they help you.
3784 =head2 Alternative math libraries
3786 You can use an alternative library to drive Math::BigInt via:
3788 use Math::BigInt lib => 'Module';
3790 See L<MATH LIBRARY> for more information.
3792 For more benchmark results see L<http://bloodgate.com/perl/benchmarks.html>.
3796 =head1 Subclassing Math::BigInt
3798 The basic design of Math::BigInt allows simple subclasses with very little
3799 work, as long as a few simple rules are followed:
3805 The public API must remain consistent, i.e. if a sub-class is overloading
3806 addition, the sub-class must use the same name, in this case badd(). The
3807 reason for this is that Math::BigInt is optimized to call the object methods
3812 The private object hash keys like C<$x->{sign}> may not be changed, but
3813 additional keys can be added, like C<$x->{_custom}>.
3817 Accessor functions are available for all existing object hash keys and should
3818 be used instead of directly accessing the internal hash keys. The reason for
3819 this is that Math::BigInt itself has a pluggable interface which permits it
3820 to support different storage methods.
3824 More complex sub-classes may have to replicate more of the logic internal of
3825 Math::BigInt if they need to change more basic behaviors. A subclass that
3826 needs to merely change the output only needs to overload C<bstr()>.
3828 All other object methods and overloaded functions can be directly inherited
3829 from the parent class.
3831 At the very minimum, any subclass will need to provide it's own C<new()> and can
3832 store additional hash keys in the object. There are also some package globals
3833 that must be defined, e.g.:
3837 $precision = -2; # round to 2 decimal places
3838 $round_mode = 'even';
3841 Additionally, you might want to provide the following two globals to allow
3842 auto-upgrading and auto-downgrading to work correctly:
3847 This allows Math::BigInt to correctly retrieve package globals from the
3848 subclass, like C<$SubClass::precision>. See t/Math/BigInt/Subclass.pm or
3849 t/Math/BigFloat/SubClass.pm completely functional subclass examples.
3855 in your subclass to automatically inherit the overloading from the parent. If
3856 you like, you can change part of the overloading, look at Math::String for an
3861 When used like this:
3863 use Math::BigInt upgrade => 'Foo::Bar';
3865 certain operations will 'upgrade' their calculation and thus the result to
3866 the class Foo::Bar. Usually this is used in conjunction with Math::BigFloat:
3868 use Math::BigInt upgrade => 'Math::BigFloat';
3870 As a shortcut, you can use the module C<bignum>:
3874 Also good for oneliners:
3876 perl -Mbignum -le 'print 2 ** 255'
3878 This makes it possible to mix arguments of different classes (as in 2.5 + 2)
3879 as well es preserve accuracy (as in sqrt(3)).
3881 Beware: This feature is not fully implemented yet.
3885 The following methods upgrade themselves unconditionally; that is if upgrade
3886 is in effect, they will always hand up their work:
3898 Beware: This list is not complete.
3900 All other methods upgrade themselves only when one (or all) of their
3901 arguments are of the class mentioned in $upgrade (This might change in later
3902 versions to a more sophisticated scheme):
3908 =item broot() does not work
3910 The broot() function in BigInt may only work for small values. This will be
3911 fixed in a later version.
3913 =item Out of Memory!
3915 Under Perl prior to 5.6.0 having an C<use Math::BigInt ':constant';> and
3916 C<eval()> in your code will crash with "Out of memory". This is probably an
3917 overload/exporter bug. You can workaround by not having C<eval()>
3918 and ':constant' at the same time or upgrade your Perl to a newer version.
3920 =item Fails to load Calc on Perl prior 5.6.0
3922 Since eval(' use ...') can not be used in conjunction with ':constant', BigInt
3923 will fall back to eval { require ... } when loading the math lib on Perls
3924 prior to 5.6.0. This simple replaces '::' with '/' and thus might fail on
3925 filesystems using a different seperator.
3931 Some things might not work as you expect them. Below is documented what is
3932 known to be troublesome:
3936 =item bstr(), bsstr() and 'cmp'
3938 Both C<bstr()> and C<bsstr()> as well as automated stringify via overload now
3939 drop the leading '+'. The old code would return '+3', the new returns '3'.
3940 This is to be consistent with Perl and to make C<cmp> (especially with
3941 overloading) to work as you expect. It also solves problems with C<Test.pm>,
3942 because it's C<ok()> uses 'eq' internally.
3944 Mark Biggar said, when asked about to drop the '+' altogether, or make only
3947 I agree (with the first alternative), don't add the '+' on positive
3948 numbers. It's not as important anymore with the new internal
3949 form for numbers. It made doing things like abs and neg easier,
3950 but those have to be done differently now anyway.
3952 So, the following examples will now work all as expected:
3955 BEGIN { plan tests => 1 }
3958 my $x = new Math::BigInt 3*3;
3959 my $y = new Math::BigInt 3*3;
3962 print "$x eq 9" if $x eq $y;
3963 print "$x eq 9" if $x eq '9';
3964 print "$x eq 9" if $x eq 3*3;
3966 Additionally, the following still works:
3968 print "$x == 9" if $x == $y;
3969 print "$x == 9" if $x == 9;
3970 print "$x == 9" if $x == 3*3;
3972 There is now a C<bsstr()> method to get the string in scientific notation aka
3973 C<1e+2> instead of C<100>. Be advised that overloaded 'eq' always uses bstr()
3974 for comparisation, but Perl will represent some numbers as 100 and others
3975 as 1e+308. If in doubt, convert both arguments to Math::BigInt before
3976 comparing them as strings:
3979 BEGIN { plan tests => 3 }
3982 $x = Math::BigInt->new('1e56'); $y = 1e56;
3983 ok ($x,$y); # will fail
3984 ok ($x->bsstr(),$y); # okay
3985 $y = Math::BigInt->new($y);
3988 Alternatively, simple use C<< <=> >> for comparisations, this will get it
3989 always right. There is not yet a way to get a number automatically represented
3990 as a string that matches exactly the way Perl represents it.
3994 C<int()> will return (at least for Perl v5.7.1 and up) another BigInt, not a
3997 $x = Math::BigInt->new(123);
3998 $y = int($x); # BigInt 123
3999 $x = Math::BigFloat->new(123.45);
4000 $y = int($x); # BigInt 123
4002 In all Perl versions you can use C<as_number()> for the same effect:
4004 $x = Math::BigFloat->new(123.45);
4005 $y = $x->as_number(); # BigInt 123
4007 This also works for other subclasses, like Math::String.
4009 It is yet unlcear whether overloaded int() should return a scalar or a BigInt.
4013 The following will probably not do what you expect:
4015 $c = Math::BigInt->new(123);
4016 print $c->length(),"\n"; # prints 30
4018 It prints both the number of digits in the number and in the fraction part
4019 since print calls C<length()> in list context. Use something like:
4021 print scalar $c->length(),"\n"; # prints 3
4025 The following will probably not do what you expect:
4027 print $c->bdiv(10000),"\n";
4029 It prints both quotient and remainder since print calls C<bdiv()> in list
4030 context. Also, C<bdiv()> will modify $c, so be carefull. You probably want
4033 print $c / 10000,"\n";
4034 print scalar $c->bdiv(10000),"\n"; # or if you want to modify $c
4038 The quotient is always the greatest integer less than or equal to the
4039 real-valued quotient of the two operands, and the remainder (when it is
4040 nonzero) always has the same sign as the second operand; so, for
4050 As a consequence, the behavior of the operator % agrees with the
4051 behavior of Perl's built-in % operator (as documented in the perlop
4052 manpage), and the equation
4054 $x == ($x / $y) * $y + ($x % $y)
4056 holds true for any $x and $y, which justifies calling the two return
4057 values of bdiv() the quotient and remainder. The only exception to this rule
4058 are when $y == 0 and $x is negative, then the remainder will also be
4059 negative. See below under "infinity handling" for the reasoning behing this.
4061 Perl's 'use integer;' changes the behaviour of % and / for scalars, but will
4062 not change BigInt's way to do things. This is because under 'use integer' Perl
4063 will do what the underlying C thinks is right and this is different for each
4064 system. If you need BigInt's behaving exactly like Perl's 'use integer', bug
4065 the author to implement it ;)
4067 =item infinity handling
4069 Here are some examples that explain the reasons why certain results occur while
4072 The following table shows the result of the division and the remainder, so that
4073 the equation above holds true. Some "ordinary" cases are strewn in to show more
4074 clearly the reasoning:
4076 A / B = C, R so that C * B + R = A
4077 =========================================================
4078 5 / 8 = 0, 5 0 * 8 + 5 = 5
4079 0 / 8 = 0, 0 0 * 8 + 0 = 0
4080 0 / inf = 0, 0 0 * inf + 0 = 0
4081 0 /-inf = 0, 0 0 * -inf + 0 = 0
4082 5 / inf = 0, 5 0 * inf + 5 = 5
4083 5 /-inf = 0, 5 0 * -inf + 5 = 5
4084 -5/ inf = 0, -5 0 * inf + -5 = -5
4085 -5/-inf = 0, -5 0 * -inf + -5 = -5
4086 inf/ 5 = inf, 0 inf * 5 + 0 = inf
4087 -inf/ 5 = -inf, 0 -inf * 5 + 0 = -inf
4088 inf/ -5 = -inf, 0 -inf * -5 + 0 = inf
4089 -inf/ -5 = inf, 0 inf * -5 + 0 = -inf
4090 5/ 5 = 1, 0 1 * 5 + 0 = 5
4091 -5/ -5 = 1, 0 1 * -5 + 0 = -5
4092 inf/ inf = 1, 0 1 * inf + 0 = inf
4093 -inf/-inf = 1, 0 1 * -inf + 0 = -inf
4094 inf/-inf = -1, 0 -1 * -inf + 0 = inf
4095 -inf/ inf = -1, 0 1 * -inf + 0 = -inf
4096 8/ 0 = inf, 8 inf * 0 + 8 = 8
4097 inf/ 0 = inf, inf inf * 0 + inf = inf
4100 These cases below violate the "remainder has the sign of the second of the two
4101 arguments", since they wouldn't match up otherwise.
4103 A / B = C, R so that C * B + R = A
4104 ========================================================
4105 -inf/ 0 = -inf, -inf -inf * 0 + inf = -inf
4106 -8/ 0 = -inf, -8 -inf * 0 + 8 = -8
4108 =item Modifying and =
4112 $x = Math::BigFloat->new(5);
4115 It will not do what you think, e.g. making a copy of $x. Instead it just makes
4116 a second reference to the B<same> object and stores it in $y. Thus anything
4117 that modifies $x (except overloaded operators) will modify $y, and vice versa.
4118 Or in other words, C<=> is only safe if you modify your BigInts only via
4119 overloaded math. As soon as you use a method call it breaks:
4122 print "$x, $y\n"; # prints '10, 10'
4124 If you want a true copy of $x, use:
4128 You can also chain the calls like this, this will make first a copy and then
4131 $y = $x->copy()->bmul(2);
4133 See also the documentation for overload.pm regarding C<=>.
4137 C<bpow()> (and the rounding functions) now modifies the first argument and
4138 returns it, unlike the old code which left it alone and only returned the
4139 result. This is to be consistent with C<badd()> etc. The first three will
4140 modify $x, the last one won't:
4142 print bpow($x,$i),"\n"; # modify $x
4143 print $x->bpow($i),"\n"; # ditto
4144 print $x **= $i,"\n"; # the same
4145 print $x ** $i,"\n"; # leave $x alone
4147 The form C<$x **= $y> is faster than C<$x = $x ** $y;>, though.
4149 =item Overloading -$x
4159 since overload calls C<sub($x,0,1);> instead of C<neg($x)>. The first variant
4160 needs to preserve $x since it does not know that it later will get overwritten.
4161 This makes a copy of $x and takes O(N), but $x->bneg() is O(1).
4163 With Copy-On-Write, this issue would be gone, but C-o-W is not implemented
4164 since it is slower for all other things.
4166 =item Mixing different object types
4168 In Perl you will get a floating point value if you do one of the following:
4174 With overloaded math, only the first two variants will result in a BigFloat:
4179 $mbf = Math::BigFloat->new(5);
4180 $mbi2 = Math::BigInteger->new(5);
4181 $mbi = Math::BigInteger->new(2);
4183 # what actually gets called:
4184 $float = $mbf + $mbi; # $mbf->badd()
4185 $float = $mbf / $mbi; # $mbf->bdiv()
4186 $integer = $mbi + $mbf; # $mbi->badd()
4187 $integer = $mbi2 / $mbi; # $mbi2->bdiv()
4188 $integer = $mbi2 / $mbf; # $mbi2->bdiv()
4190 This is because math with overloaded operators follows the first (dominating)
4191 operand, and the operation of that is called and returns thus the result. So,
4192 Math::BigInt::bdiv() will always return a Math::BigInt, regardless whether
4193 the result should be a Math::BigFloat or the second operant is one.
4195 To get a Math::BigFloat you either need to call the operation manually,
4196 make sure the operands are already of the proper type or casted to that type
4197 via Math::BigFloat->new():
4199 $float = Math::BigFloat->new($mbi2) / $mbi; # = 2.5
4201 Beware of simple "casting" the entire expression, this would only convert
4202 the already computed result:
4204 $float = Math::BigFloat->new($mbi2 / $mbi); # = 2.0 thus wrong!
4206 Beware also of the order of more complicated expressions like:
4208 $integer = ($mbi2 + $mbi) / $mbf; # int / float => int
4209 $integer = $mbi2 / Math::BigFloat->new($mbi); # ditto
4211 If in doubt, break the expression into simpler terms, or cast all operands
4212 to the desired resulting type.
4214 Scalar values are a bit different, since:
4219 will both result in the proper type due to the way the overloaded math works.
4221 This section also applies to other overloaded math packages, like Math::String.
4223 One solution to you problem might be autoupgrading|upgrading. See the
4224 pragmas L<bignum>, L<bigint> and L<bigrat> for an easy way to do this.
4228 C<bsqrt()> works only good if the result is a big integer, e.g. the square
4229 root of 144 is 12, but from 12 the square root is 3, regardless of rounding
4230 mode. The reason is that the result is always truncated to an integer.
4232 If you want a better approximation of the square root, then use:
4234 $x = Math::BigFloat->new(12);
4235 Math::BigFloat->precision(0);
4236 Math::BigFloat->round_mode('even');
4237 print $x->copy->bsqrt(),"\n"; # 4
4239 Math::BigFloat->precision(2);
4240 print $x->bsqrt(),"\n"; # 3.46
4241 print $x->bsqrt(3),"\n"; # 3.464
4245 For negative numbers in base see also L<brsft|brsft>.
4251 This program is free software; you may redistribute it and/or modify it under
4252 the same terms as Perl itself.
4256 L<Math::BigFloat>, L<Math::BigRat> and L<Math::Big> as well as
4257 L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>.
4259 The pragmas L<bignum>, L<bigint> and L<bigrat> also might be of interest
4260 because they solve the autoupgrading/downgrading issue, at least partly.
4263 L<http://search.cpan.org/search?mode=module&query=Math%3A%3ABigInt> contains
4264 more documentation including a full version history, testcases, empty
4265 subclass files and benchmarks.
4269 Original code by Mark Biggar, overloaded interface by Ilya Zakharevich.
4270 Completely rewritten by Tels http://bloodgate.com in late 2000, 2001 - 2003
4271 and still at it in 2004.
4273 Many people contributed in one or more ways to the final beast, see the file
4274 CREDITS for an (uncomplete) list. If you miss your name, please drop me a