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 $class = "Math::BigInt";
23 @ISA = qw( Exporter );
24 @EXPORT_OK = qw( objectify _swap bgcd blcm);
25 use vars qw/$round_mode $accuracy $precision $div_scale $rnd_mode/;
26 use vars qw/$upgrade $downgrade/;
27 # the following are internal and should never be accessed from the outside
28 use vars qw/$_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 indicates this
33 # swapping. To make it work, we use a helper routine which not only reswaps the
34 # params, but also makes a new object in this case. See _swap() for details,
35 # especially the cases of operators with different classes.
37 # For overloaded ops with only one argument we simple use $_[0]->copy() to
38 # preserve the argument.
40 # Thus inheritance of overload operators becomes possible and transparent for
41 # our subclasses without the need to repeat the entire overload section there.
44 '=' => sub { $_[0]->copy(); },
46 # '+' and '-' do not use _swap, since it is a triffle slower. If you want to
47 # override _swap (if ever), then override overload of '+' and '-', too!
48 # for sub it is a bit tricky to keep b: b-a => -a+b
49 '-' => sub { my $c = $_[0]->copy; $_[2] ?
50 $c->bneg()->badd($_[1]) :
52 '+' => sub { $_[0]->copy()->badd($_[1]); },
54 # some shortcuts for speed (assumes that reversed order of arguments is routed
55 # to normal '+' and we thus can always modify first arg. If this is changed,
56 # this breaks and must be adjusted.)
57 '+=' => sub { $_[0]->badd($_[1]); },
58 '-=' => sub { $_[0]->bsub($_[1]); },
59 '*=' => sub { $_[0]->bmul($_[1]); },
60 '/=' => sub { scalar $_[0]->bdiv($_[1]); },
61 '%=' => sub { $_[0]->bmod($_[1]); },
62 '^=' => sub { $_[0]->bxor($_[1]); },
63 '&=' => sub { $_[0]->band($_[1]); },
64 '|=' => sub { $_[0]->bior($_[1]); },
65 '**=' => sub { $_[0]->bpow($_[1]); },
67 # not supported by Perl yet
68 '..' => \&_pointpoint,
70 '<=>' => sub { $_[2] ?
71 ref($_[0])->bcmp($_[1],$_[0]) :
75 "$_[1]" cmp $_[0]->bstr() :
76 $_[0]->bstr() cmp "$_[1]" },
78 'log' => sub { $_[0]->copy()->blog(); },
79 'int' => sub { $_[0]->copy(); },
80 'neg' => sub { $_[0]->copy()->bneg(); },
81 'abs' => sub { $_[0]->copy()->babs(); },
82 'sqrt' => sub { $_[0]->copy()->bsqrt(); },
83 '~' => sub { $_[0]->copy()->bnot(); },
85 '*' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->bmul($a[1]); },
86 '/' => sub { my @a = ref($_[0])->_swap(@_);scalar $a[0]->bdiv($a[1]);},
87 '%' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->bmod($a[1]); },
88 '**' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->bpow($a[1]); },
89 '<<' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->blsft($a[1]); },
90 '>>' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->brsft($a[1]); },
92 '&' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->band($a[1]); },
93 '|' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->bior($a[1]); },
94 '^' => sub { my @a = ref($_[0])->_swap(@_); $a[0]->bxor($a[1]); },
96 # can modify arg of ++ and --, so avoid a new-copy for speed, but don't
97 # use $_[0]->__one(), it modifies $_[0] to be 1!
98 '++' => sub { $_[0]->binc() },
99 '--' => sub { $_[0]->bdec() },
101 # if overloaded, O(1) instead of O(N) and twice as fast for small numbers
103 # this kludge is needed for perl prior 5.6.0 since returning 0 here fails :-/
104 # v5.6.1 dumps on that: return !$_[0]->is_zero() || undef; :-(
105 my $t = !$_[0]->is_zero();
110 # the original qw() does not work with the TIESCALAR below, why?
111 # Order of arguments unsignificant
112 '""' => sub { $_[0]->bstr(); },
113 '0+' => sub { $_[0]->numify(); }
116 ##############################################################################
117 # global constants, flags and accessory
119 # these are public, but their usage is not recommended, use the accessor
122 $round_mode = 'even'; # one of 'even', 'odd', '+inf', '-inf', 'zero' or 'trunc'
127 $upgrade = undef; # default is no upgrade
128 $downgrade = undef; # default is no downgrade
130 # these are internally, and not to be used from the outside
132 use constant MB_NEVER_ROUND => 0x0001;
134 $_trap_nan = 0; # are NaNs ok? set w/ config()
135 $_trap_inf = 0; # are infs ok? set w/ config()
136 my $nan = 'NaN'; # constants for easier life
138 my $CALC = 'Math::BigInt::Calc'; # module to do the low level math
139 my $IMPORT = 0; # was import() called yet?
140 # used to make require work
142 ##############################################################################
143 # the old code had $rnd_mode, so we need to support it, too
146 sub TIESCALAR { my ($class) = @_; bless \$round_mode, $class; }
147 sub FETCH { return $round_mode; }
148 sub STORE { $rnd_mode = $_[0]->round_mode($_[1]); }
150 BEGIN { tie $rnd_mode, 'Math::BigInt'; }
152 ##############################################################################
157 # make Class->round_mode() work
159 my $class = ref($self) || $self || __PACKAGE__;
163 if ($m !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
165 require Carp; Carp::croak ("Unknown round mode '$m'");
167 return ${"${class}::round_mode"} = $m;
169 ${"${class}::round_mode"};
175 # make Class->upgrade() work
177 my $class = ref($self) || $self || __PACKAGE__;
178 # need to set new value?
182 return ${"${class}::upgrade"} = $u;
184 ${"${class}::upgrade"};
190 # make Class->downgrade() work
192 my $class = ref($self) || $self || __PACKAGE__;
193 # need to set new value?
197 return ${"${class}::downgrade"} = $u;
199 ${"${class}::downgrade"};
205 # make Class->div_scale() work
207 my $class = ref($self) || $self || __PACKAGE__;
212 require Carp; Carp::croak ('div_scale must be greater than zero');
214 ${"${class}::div_scale"} = shift;
216 ${"${class}::div_scale"};
221 # $x->accuracy($a); ref($x) $a
222 # $x->accuracy(); ref($x)
223 # Class->accuracy(); class
224 # Class->accuracy($a); class $a
227 my $class = ref($x) || $x || __PACKAGE__;
230 # need to set new value?
234 # convert objects to scalars to avoid deep recursion. If object doesn't
235 # have numify(), then hopefully it will have overloading for int() and
236 # boolean test without wandering into a deep recursion path...
237 $a = $a->numify() if ref($a) && $a->can('numify');
241 # also croak on non-numerical
245 Carp::croak ('Argument to accuracy must be greater than zero');
249 require Carp; Carp::croak ('Argument to accuracy must be an integer');
254 # $object->accuracy() or fallback to global
255 $x->bround($a) if $a; # not for undef, 0
256 $x->{_a} = $a; # set/overwrite, even if not rounded
257 $x->{_p} = undef; # clear P
258 $a = ${"${class}::accuracy"} unless defined $a; # proper return value
263 ${"${class}::accuracy"} = $a;
264 ${"${class}::precision"} = undef; # clear P
266 return $a; # shortcut
270 # $object->accuracy() or fallback to global
271 $r = $x->{_a} if ref($x);
272 # but don't return global undef, when $x's accuracy is 0!
273 $r = ${"${class}::accuracy"} if !defined $r;
279 # $x->precision($p); ref($x) $p
280 # $x->precision(); ref($x)
281 # Class->precision(); class
282 # Class->precision($p); class $p
285 my $class = ref($x) || $x || __PACKAGE__;
291 # convert objects to scalars to avoid deep recursion. If object doesn't
292 # have numify(), then hopefully it will have overloading for int() and
293 # boolean test without wandering into a deep recursion path...
294 $p = $p->numify() if ref($p) && $p->can('numify');
295 if ((defined $p) && (int($p) != $p))
297 require Carp; Carp::croak ('Argument to precision must be an integer');
301 # $object->precision() or fallback to global
302 $x->bfround($p) if $p; # not for undef, 0
303 $x->{_p} = $p; # set/overwrite, even if not rounded
304 $x->{_a} = undef; # clear A
305 $p = ${"${class}::precision"} unless defined $p; # proper return value
310 ${"${class}::precision"} = $p;
311 ${"${class}::accuracy"} = undef; # clear A
313 return $p; # shortcut
317 # $object->precision() or fallback to global
318 $r = $x->{_p} if ref($x);
319 # but don't return global undef, when $x's precision is 0!
320 $r = ${"${class}::precision"} if !defined $r;
326 # return (or set) configuration data as hash ref
327 my $class = shift || 'Math::BigInt';
332 # try to set given options as arguments from hash
335 if (ref($args) ne 'HASH')
339 # these values can be "set"
343 upgrade downgrade precision accuracy round_mode div_scale/
346 $set_args->{$key} = $args->{$key} if exists $args->{$key};
347 delete $args->{$key};
352 Carp::croak ("Illegal key(s) '",
353 join("','",keys %$args),"' passed to $class\->config()");
355 foreach my $key (keys %$set_args)
357 if ($key =~ /^trap_(inf|nan)\z/)
359 ${"${class}::_trap_$1"} = ($set_args->{"trap_$1"} ? 1 : 0);
362 # use a call instead of just setting the $variable to check argument
363 $class->$key($set_args->{$key});
367 # now return actual configuration
371 lib_version => ${"${CALC}::VERSION"},
373 trap_nan => ${"${class}::_trap_nan"},
374 trap_inf => ${"${class}::_trap_inf"},
375 version => ${"${class}::VERSION"},
378 upgrade downgrade precision accuracy round_mode div_scale
381 $cfg->{$key} = ${"${class}::$key"};
388 # select accuracy parameter based on precedence,
389 # used by bround() and bfround(), may return undef for scale (means no op)
390 my ($x,$s,$m,$scale,$mode) = @_;
391 $scale = $x->{_a} if !defined $scale;
392 $scale = $s if (!defined $scale);
393 $mode = $m if !defined $mode;
394 return ($scale,$mode);
399 # select precision parameter based on precedence,
400 # used by bround() and bfround(), may return undef for scale (means no op)
401 my ($x,$s,$m,$scale,$mode) = @_;
402 $scale = $x->{_p} if !defined $scale;
403 $scale = $s if (!defined $scale);
404 $mode = $m if !defined $mode;
405 return ($scale,$mode);
408 ##############################################################################
416 # if two arguments, the first one is the class to "swallow" subclasses
424 return unless ref($x); # only for objects
426 my $self = {}; bless $self,$c;
428 foreach my $k (keys %$x)
432 $self->{value} = $CALC->_copy($x->{value}); next;
434 if (!($r = ref($x->{$k})))
436 $self->{$k} = $x->{$k}; next;
440 $self->{$k} = \${$x->{$k}};
442 elsif ($r eq 'ARRAY')
444 $self->{$k} = [ @{$x->{$k}} ];
448 # only one level deep!
449 foreach my $h (keys %{$x->{$k}})
451 $self->{$k}->{$h} = $x->{$k}->{$h};
457 if ($xk->can('copy'))
459 $self->{$k} = $xk->copy();
463 $self->{$k} = $xk->new($xk);
472 # create a new BigInt object from a string or another BigInt object.
473 # see hash keys documented at top
475 # the argument could be an object, so avoid ||, && etc on it, this would
476 # cause costly overloaded code to be called. The only allowed ops are
479 my ($class,$wanted,$a,$p,$r) = @_;
481 # avoid numify-calls by not using || on $wanted!
482 return $class->bzero($a,$p) if !defined $wanted; # default to 0
483 return $class->copy($wanted,$a,$p,$r)
484 if ref($wanted) && $wanted->isa($class); # MBI or subclass
486 $class->import() if $IMPORT == 0; # make require work
488 my $self = bless {}, $class;
490 # shortcut for "normal" numbers
491 if ((!ref $wanted) && ($wanted =~ /^([+-]?)[1-9][0-9]*\z/))
493 $self->{sign} = $1 || '+';
495 if ($wanted =~ /^[+-]/)
497 # remove sign without touching wanted to make it work with constants
498 my $t = $wanted; $t =~ s/^[+-]//; $ref = \$t;
500 # force to string version (otherwise Pari is unhappy about overflowed
501 # constants, for instance)
502 # not good, BigInt shouldn't need to know about alternative libs:
503 # $ref = \"$$ref" if $CALC eq 'Math::BigInt::Pari';
504 $self->{value} = $CALC->_new($ref);
506 if ( (defined $a) || (defined $p)
507 || (defined ${"${class}::precision"})
508 || (defined ${"${class}::accuracy"})
511 $self->round($a,$p,$r) unless (@_ == 4 && !defined $a && !defined $p);
516 # handle '+inf', '-inf' first
517 if ($wanted =~ /^[+-]?inf$/)
519 $self->{value} = $CALC->_zero();
520 $self->{sign} = $wanted; $self->{sign} = '+inf' if $self->{sign} eq 'inf';
523 # split str in m mantissa, e exponent, i integer, f fraction, v value, s sign
524 my ($mis,$miv,$mfv,$es,$ev) = _split(\$wanted);
529 require Carp; Carp::croak("$wanted is not a number in $class");
531 $self->{value} = $CALC->_zero();
532 $self->{sign} = $nan;
537 # _from_hex or _from_bin
538 $self->{value} = $mis->{value};
539 $self->{sign} = $mis->{sign};
540 return $self; # throw away $mis
542 # make integer from mantissa by adjusting exp, then convert to bigint
543 $self->{sign} = $$mis; # store sign
544 $self->{value} = $CALC->_zero(); # for all the NaN cases
545 my $e = int("$$es$$ev"); # exponent (avoid recursion)
548 my $diff = $e - CORE::length($$mfv);
549 if ($diff < 0) # Not integer
553 require Carp; Carp::croak("$wanted not an integer in $class");
556 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
557 $self->{sign} = $nan;
561 # adjust fraction and add it to value
562 #print "diff > 0 $$miv\n";
563 $$miv = $$miv . ($$mfv . '0' x $diff);
568 if ($$mfv ne '') # e <= 0
570 # fraction and negative/zero E => NOI
573 require Carp; Carp::croak("$wanted not an integer in $class");
575 #print "NOI 2 \$\$mfv '$$mfv'\n";
576 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
577 $self->{sign} = $nan;
581 # xE-y, and empty mfv
584 if ($$miv !~ s/0{$e}$//) # can strip so many zero's?
588 require Carp; Carp::croak("$wanted not an integer in $class");
591 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
592 $self->{sign} = $nan;
596 $self->{sign} = '+' if $$miv eq '0'; # normalize -0 => +0
597 $self->{value} = $CALC->_new($miv) if $self->{sign} =~ /^[+-]$/;
598 # if any of the globals is set, use them to round and store them inside $self
599 # do not round for new($x,undef,undef) since that is used by MBF to signal
601 $self->round($a,$p,$r) unless @_ == 4 && !defined $a && !defined $p;
607 # create a bigint 'NaN', if given a BigInt, set it to 'NaN'
609 $self = $class if !defined $self;
612 my $c = $self; $self = {}; bless $self, $c;
615 if (${"${class}::_trap_nan"})
618 Carp::croak ("Tried to set $self to NaN in $class\::bnan()");
620 $self->import() if $IMPORT == 0; # make require work
621 return if $self->modify('bnan');
622 if ($self->can('_bnan'))
624 # use subclass to initialize
629 # otherwise do our own thing
630 $self->{value} = $CALC->_zero();
632 $self->{sign} = $nan;
633 delete $self->{_a}; delete $self->{_p}; # rounding NaN is silly
639 # create a bigint '+-inf', if given a BigInt, set it to '+-inf'
640 # the sign is either '+', or if given, used from there
642 my $sign = shift; $sign = '+' if !defined $sign || $sign !~ /^-(inf)?$/;
643 $self = $class if !defined $self;
646 my $c = $self; $self = {}; bless $self, $c;
649 if (${"${class}::_trap_inf"})
652 Carp::croak ("Tried to set $self to +-inf in $class\::binfn()");
654 $self->import() if $IMPORT == 0; # make require work
655 return if $self->modify('binf');
656 if ($self->can('_binf'))
658 # use subclass to initialize
663 # otherwise do our own thing
664 $self->{value} = $CALC->_zero();
666 $sign = $sign . 'inf' if $sign !~ /inf$/; # - => -inf
667 $self->{sign} = $sign;
668 ($self->{_a},$self->{_p}) = @_; # take over requested rounding
674 # create a bigint '+0', if given a BigInt, set it to 0
676 $self = $class if !defined $self;
680 my $c = $self; $self = {}; bless $self, $c;
682 $self->import() if $IMPORT == 0; # make require work
683 return if $self->modify('bzero');
685 if ($self->can('_bzero'))
687 # use subclass to initialize
692 # otherwise do our own thing
693 $self->{value} = $CALC->_zero();
700 # call like: $x->bzero($a,$p,$r,$y);
701 ($self,$self->{_a},$self->{_p}) = $self->_find_round_parameters(@_);
706 if ( (!defined $self->{_a}) || (defined $_[0] && $_[0] > $self->{_a}));
708 if ( (!defined $self->{_p}) || (defined $_[1] && $_[1] > $self->{_p}));
716 # create a bigint '+1' (or -1 if given sign '-'),
717 # if given a BigInt, set it to +1 or -1, respecively
719 my $sign = shift; $sign = '+' if !defined $sign || $sign ne '-';
720 $self = $class if !defined $self;
724 my $c = $self; $self = {}; bless $self, $c;
726 $self->import() if $IMPORT == 0; # make require work
727 return if $self->modify('bone');
729 if ($self->can('_bone'))
731 # use subclass to initialize
736 # otherwise do our own thing
737 $self->{value} = $CALC->_one();
739 $self->{sign} = $sign;
744 # call like: $x->bone($sign,$a,$p,$r,$y);
745 ($self,$self->{_a},$self->{_p}) = $self->_find_round_parameters(@_);
750 if ( (!defined $self->{_a}) || (defined $_[0] && $_[0] > $self->{_a}));
752 if ( (!defined $self->{_p}) || (defined $_[1] && $_[1] > $self->{_p}));
758 ##############################################################################
759 # string conversation
763 # (ref to BFLOAT or num_str ) return num_str
764 # Convert number from internal format to scientific string format.
765 # internal format is always normalized (no leading zeros, "-0E0" => "+0E0")
766 my $x = shift; $class = ref($x) || $x; $x = $class->new(shift) if !ref($x);
767 # my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
769 if ($x->{sign} !~ /^[+-]$/)
771 return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
774 my ($m,$e) = $x->parts();
775 my $sign = 'e+'; # e can only be positive
776 return $m->bstr().$sign.$e->bstr();
781 # make a string from bigint object
782 my $x = shift; $class = ref($x) || $x; $x = $class->new(shift) if !ref($x);
783 # my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
785 if ($x->{sign} !~ /^[+-]$/)
787 return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
790 my $es = ''; $es = $x->{sign} if $x->{sign} eq '-';
791 return $es.${$CALC->_str($x->{value})};
796 # Make a "normal" scalar from a BigInt object
797 my $x = shift; $x = $class->new($x) unless ref $x;
799 return $x->bstr() if $x->{sign} !~ /^[+-]$/;
800 my $num = $CALC->_num($x->{value});
801 return -$num if $x->{sign} eq '-';
805 ##############################################################################
806 # public stuff (usually prefixed with "b")
810 # return the sign of the number: +/-/-inf/+inf/NaN
811 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
816 sub _find_round_parameters
818 # After any operation or when calling round(), the result is rounded by
819 # regarding the A & P from arguments, local parameters, or globals.
821 # !!!!!!! If you change this, remember to change round(), too! !!!!!!!!!!
823 # This procedure finds the round parameters, but it is for speed reasons
824 # duplicated in round. Otherwise, it is tested by the testsuite and used
827 # returns ($self) or ($self,$a,$p,$r) - sets $self to NaN of both A and P
828 # were requested/defined (locally or globally or both)
830 my ($self,$a,$p,$r,@args) = @_;
831 # $a accuracy, if given by caller
832 # $p precision, if given by caller
833 # $r round_mode, if given by caller
834 # @args all 'other' arguments (0 for unary, 1 for binary ops)
836 # leave bigfloat parts alone
837 return ($self) if exists $self->{_f} && ($self->{_f} & MB_NEVER_ROUND) != 0;
839 my $c = ref($self); # find out class of argument(s)
842 # now pick $a or $p, but only if we have got "arguments"
845 foreach ($self,@args)
847 # take the defined one, or if both defined, the one that is smaller
848 $a = $_->{_a} if (defined $_->{_a}) && (!defined $a || $_->{_a} < $a);
853 # even if $a is defined, take $p, to signal error for both defined
854 foreach ($self,@args)
856 # take the defined one, or if both defined, the one that is bigger
858 $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} > $p);
861 # if still none defined, use globals (#2)
862 $a = ${"$c\::accuracy"} unless defined $a;
863 $p = ${"$c\::precision"} unless defined $p;
865 # A == 0 is useless, so undef it to signal no rounding
866 $a = undef if defined $a && $a == 0;
869 return ($self) unless defined $a || defined $p; # early out
871 # set A and set P is an fatal error
872 return ($self->bnan()) if defined $a && defined $p; # error
874 $r = ${"$c\::round_mode"} unless defined $r;
875 if ($r !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
877 require Carp; Carp::croak ("Unknown round mode '$r'");
885 # Round $self according to given parameters, or given second argument's
886 # parameters or global defaults
888 # for speed reasons, _find_round_parameters is embeded here:
890 my ($self,$a,$p,$r,@args) = @_;
891 # $a accuracy, if given by caller
892 # $p precision, if given by caller
893 # $r round_mode, if given by caller
894 # @args all 'other' arguments (0 for unary, 1 for binary ops)
896 # leave bigfloat parts alone
897 return ($self) if exists $self->{_f} && ($self->{_f} & MB_NEVER_ROUND) != 0;
899 my $c = ref($self); # find out class of argument(s)
902 # now pick $a or $p, but only if we have got "arguments"
905 foreach ($self,@args)
907 # take the defined one, or if both defined, the one that is smaller
908 $a = $_->{_a} if (defined $_->{_a}) && (!defined $a || $_->{_a} < $a);
913 # even if $a is defined, take $p, to signal error for both defined
914 foreach ($self,@args)
916 # take the defined one, or if both defined, the one that is bigger
918 $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} > $p);
921 # if still none defined, use globals (#2)
922 $a = ${"$c\::accuracy"} unless defined $a;
923 $p = ${"$c\::precision"} unless defined $p;
925 # A == 0 is useless, so undef it to signal no rounding
926 $a = undef if defined $a && $a == 0;
929 return $self unless defined $a || defined $p; # early out
931 # set A and set P is an fatal error
932 return $self->bnan() if defined $a && defined $p;
934 $r = ${"$c\::round_mode"} unless defined $r;
935 if ($r !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
940 # now round, by calling either fround or ffround:
943 $self->bround($a,$r) if !defined $self->{_a} || $self->{_a} >= $a;
945 else # both can't be undefined due to early out
947 $self->bfround($p,$r) if !defined $self->{_p} || $self->{_p} <= $p;
949 $self->bnorm(); # after round, normalize
954 # (numstr or BINT) return BINT
955 # Normalize number -- no-op here
956 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
962 # (BINT or num_str) return BINT
963 # make number absolute, or return absolute BINT from string
964 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
966 return $x if $x->modify('babs');
967 # post-normalized abs for internal use (does nothing for NaN)
968 $x->{sign} =~ s/^-/+/;
974 # (BINT or num_str) return BINT
975 # negate number or make a negated number from string
976 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
978 return $x if $x->modify('bneg');
980 # for +0 dont negate (to have always normalized)
981 $x->{sign} =~ tr/+-/-+/ if !$x->is_zero(); # does nothing for NaN
987 # Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort)
988 # (BINT or num_str, BINT or num_str) return cond_code
991 my ($self,$x,$y) = (ref($_[0]),@_);
993 # objectify is costly, so avoid it
994 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
996 ($self,$x,$y) = objectify(2,@_);
999 return $upgrade->bcmp($x,$y) if defined $upgrade &&
1000 ((!$x->isa($self)) || (!$y->isa($self)));
1002 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1004 # handle +-inf and NaN
1005 return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1006 return 0 if $x->{sign} eq $y->{sign} && $x->{sign} =~ /^[+-]inf$/;
1007 return +1 if $x->{sign} eq '+inf';
1008 return -1 if $x->{sign} eq '-inf';
1009 return -1 if $y->{sign} eq '+inf';
1012 # check sign for speed first
1013 return 1 if $x->{sign} eq '+' && $y->{sign} eq '-'; # does also 0 <=> -y
1014 return -1 if $x->{sign} eq '-' && $y->{sign} eq '+'; # does also -x <=> 0
1016 # have same sign, so compare absolute values. Don't make tests for zero here
1017 # because it's actually slower than testin in Calc (especially w/ Pari et al)
1019 # post-normalized compare for internal use (honors signs)
1020 if ($x->{sign} eq '+')
1022 # $x and $y both > 0
1023 return $CALC->_acmp($x->{value},$y->{value});
1027 $CALC->_acmp($y->{value},$x->{value}); # swaped (lib returns 0,1,-1)
1032 # Compares 2 values, ignoring their signs.
1033 # Returns one of undef, <0, =0, >0. (suitable for sort)
1034 # (BINT, BINT) return cond_code
1037 my ($self,$x,$y) = (ref($_[0]),@_);
1038 # objectify is costly, so avoid it
1039 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1041 ($self,$x,$y) = objectify(2,@_);
1044 return $upgrade->bacmp($x,$y) if defined $upgrade &&
1045 ((!$x->isa($self)) || (!$y->isa($self)));
1047 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1049 # handle +-inf and NaN
1050 return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1051 return 0 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} =~ /^[+-]inf$/;
1052 return +1; # inf is always bigger
1054 $CALC->_acmp($x->{value},$y->{value}); # lib does only 0,1,-1
1059 # add second arg (BINT or string) to first (BINT) (modifies first)
1060 # return result as BINT
1063 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1064 # objectify is costly, so avoid it
1065 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1067 ($self,$x,$y,@r) = objectify(2,@_);
1070 return $x if $x->modify('badd');
1071 return $upgrade->badd($x,$y,@r) if defined $upgrade &&
1072 ((!$x->isa($self)) || (!$y->isa($self)));
1074 $r[3] = $y; # no push!
1075 # inf and NaN handling
1076 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1079 return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1081 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1083 # +inf++inf or -inf+-inf => same, rest is NaN
1084 return $x if $x->{sign} eq $y->{sign};
1087 # +-inf + something => +inf
1088 # something +-inf => +-inf
1089 $x->{sign} = $y->{sign}, return $x if $y->{sign} =~ /^[+-]inf$/;
1093 my ($sx, $sy) = ( $x->{sign}, $y->{sign} ); # get signs
1097 $x->{value} = $CALC->_add($x->{value},$y->{value}); # same sign, abs add
1102 my $a = $CALC->_acmp ($y->{value},$x->{value}); # absolute compare
1105 #print "swapped sub (a=$a)\n";
1106 $x->{value} = $CALC->_sub($y->{value},$x->{value},1); # abs sub w/ swap
1111 # speedup, if equal, set result to 0
1112 #print "equal sub, result = 0\n";
1113 $x->{value} = $CALC->_zero();
1118 #print "unswapped sub (a=$a)\n";
1119 $x->{value} = $CALC->_sub($x->{value}, $y->{value}); # abs sub
1123 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1129 # (BINT or num_str, BINT or num_str) return num_str
1130 # subtract second arg from first, modify first
1133 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1134 # objectify is costly, so avoid it
1135 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1137 ($self,$x,$y,@r) = objectify(2,@_);
1140 return $x if $x->modify('bsub');
1142 # upgrade done by badd():
1143 # return $upgrade->badd($x,$y,@r) if defined $upgrade &&
1144 # ((!$x->isa($self)) || (!$y->isa($self)));
1148 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1152 $y->{sign} =~ tr/+\-/-+/; # does nothing for NaN
1153 $x->badd($y,@r); # badd does not leave internal zeros
1154 $y->{sign} =~ tr/+\-/-+/; # refix $y (does nothing for NaN)
1155 $x; # already rounded by badd() or no round necc.
1160 # increment arg by one
1161 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1162 return $x if $x->modify('binc');
1164 if ($x->{sign} eq '+')
1166 $x->{value} = $CALC->_inc($x->{value});
1167 $x->round($a,$p,$r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1170 elsif ($x->{sign} eq '-')
1172 $x->{value} = $CALC->_dec($x->{value});
1173 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # -1 +1 => -0 => +0
1174 $x->round($a,$p,$r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1177 # inf, nan handling etc
1178 $x->badd($self->__one(),$a,$p,$r); # badd does round
1183 # decrement arg by one
1184 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1185 return $x if $x->modify('bdec');
1187 my $zero = $CALC->_is_zero($x->{value}) && $x->{sign} eq '+';
1189 if (($x->{sign} eq '-') || $zero)
1191 $x->{value} = $CALC->_inc($x->{value});
1192 $x->{sign} = '-' if $zero; # 0 => 1 => -1
1193 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # -1 +1 => -0 => +0
1194 $x->round($a,$p,$r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1198 elsif ($x->{sign} eq '+')
1200 $x->{value} = $CALC->_dec($x->{value});
1201 $x->round($a,$p,$r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1204 # inf, nan handling etc
1205 $x->badd($self->__one('-'),$a,$p,$r); # badd does round
1210 # not implemented yet
1211 my ($self,$x,$base,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1213 return $upgrade->blog($upgrade->new($x),$base,$a,$p,$r) if defined $upgrade;
1220 # (BINT or num_str, BINT or num_str) return BINT
1221 # does not modify arguments, but returns new object
1222 # Lowest Common Multiplicator
1224 my $y = shift; my ($x);
1231 $x = $class->new($y);
1233 while (@_) { $x = __lcm($x,shift); }
1239 # (BINT or num_str, BINT or num_str) return BINT
1240 # does not modify arguments, but returns new object
1241 # GCD -- Euclids algorithm, variant C (Knuth Vol 3, pg 341 ff)
1244 $y = __PACKAGE__->new($y) if !ref($y);
1246 my $x = $y->copy(); # keep arguments
1247 if ($CALC->can('_gcd'))
1251 $y = shift; $y = $self->new($y) if !ref($y);
1252 next if $y->is_zero();
1253 return $x->bnan() if $y->{sign} !~ /^[+-]$/; # y NaN?
1254 $x->{value} = $CALC->_gcd($x->{value},$y->{value}); last if $x->is_one();
1261 $y = shift; $y = $self->new($y) if !ref($y);
1262 $x = __gcd($x,$y->copy()); last if $x->is_one(); # _gcd handles NaN
1270 # (num_str or BINT) return BINT
1271 # represent ~x as twos-complement number
1272 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1273 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1275 return $x if $x->modify('bnot');
1276 $x->bneg()->bdec(); # bdec already does round
1279 # is_foo test routines
1283 # return true if arg (BINT or num_str) is zero (array '+', '0')
1284 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1285 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1287 return 0 if $x->{sign} !~ /^\+$/; # -, NaN & +-inf aren't
1288 $CALC->_is_zero($x->{value});
1293 # return true if arg (BINT or num_str) is NaN
1294 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
1296 return 1 if $x->{sign} eq $nan;
1302 # return true if arg (BINT or num_str) is +-inf
1303 my ($self,$x,$sign) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1305 $sign = '' if !defined $sign;
1306 return 1 if $sign eq $x->{sign}; # match ("+inf" eq "+inf")
1307 return 0 if $sign !~ /^([+-]|)$/;
1311 return 1 if ($x->{sign} =~ /^[+-]inf$/);
1314 $sign = quotemeta($sign.'inf');
1315 return 1 if ($x->{sign} =~ /^$sign$/);
1321 # return true if arg (BINT or num_str) is +1
1322 # or -1 if sign is given
1323 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1324 my ($self,$x,$sign) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1326 $sign = '+' if !defined $sign || $sign ne '-';
1328 return 0 if $x->{sign} ne $sign; # -1 != +1, NaN, +-inf aren't either
1329 $CALC->_is_one($x->{value});
1334 # return true when arg (BINT or num_str) is odd, false for even
1335 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1336 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1338 return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
1339 $CALC->_is_odd($x->{value});
1344 # return true when arg (BINT or num_str) is even, false for odd
1345 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1346 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1348 return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
1349 $CALC->_is_even($x->{value});
1354 # return true when arg (BINT or num_str) is positive (>= 0)
1355 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1356 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1358 return 1 if $x->{sign} =~ /^\+/;
1364 # return true when arg (BINT or num_str) is negative (< 0)
1365 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1366 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1368 return 1 if ($x->{sign} =~ /^-/);
1374 # return true when arg (BINT or num_str) is an integer
1375 # always true for BigInt, but different for Floats
1376 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1377 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1379 $x->{sign} =~ /^[+-]$/ ? 1 : 0; # inf/-inf/NaN aren't
1382 ###############################################################################
1386 # multiply two numbers -- stolen from Knuth Vol 2 pg 233
1387 # (BINT or num_str, BINT or num_str) return BINT
1390 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1391 # objectify is costly, so avoid it
1392 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1394 ($self,$x,$y,@r) = objectify(2,@_);
1397 return $x if $x->modify('bmul');
1399 return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1402 if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
1404 return $x->bnan() if $x->is_zero() || $y->is_zero();
1405 # result will always be +-inf:
1406 # +inf * +/+inf => +inf, -inf * -/-inf => +inf
1407 # +inf * -/-inf => -inf, -inf * +/+inf => -inf
1408 return $x->binf() if ($x->{sign} =~ /^\+/ && $y->{sign} =~ /^\+/);
1409 return $x->binf() if ($x->{sign} =~ /^-/ && $y->{sign} =~ /^-/);
1410 return $x->binf('-');
1413 return $upgrade->bmul($x,$y,@r)
1414 if defined $upgrade && $y->isa($upgrade);
1416 $r[3] = $y; # no push here
1418 $x->{sign} = $x->{sign} eq $y->{sign} ? '+' : '-'; # +1 * +1 or -1 * -1 => +
1420 $x->{value} = $CALC->_mul($x->{value},$y->{value}); # do actual math
1421 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # no -0
1423 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1429 # helper function that handles +-inf cases for bdiv()/bmod() to reuse code
1430 my ($self,$x,$y) = @_;
1432 # NaN if x == NaN or y == NaN or x==y==0
1433 return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan()
1434 if (($x->is_nan() || $y->is_nan()) ||
1435 ($x->is_zero() && $y->is_zero()));
1437 # +-inf / +-inf == NaN, reminder also NaN
1438 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1440 return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan();
1442 # x / +-inf => 0, remainder x (works even if x == 0)
1443 if ($y->{sign} =~ /^[+-]inf$/)
1445 my $t = $x->copy(); # bzero clobbers up $x
1446 return wantarray ? ($x->bzero(),$t) : $x->bzero()
1449 # 5 / 0 => +inf, -6 / 0 => -inf
1450 # +inf / 0 = inf, inf, and -inf / 0 => -inf, -inf
1451 # exception: -8 / 0 has remainder -8, not 8
1452 # exception: -inf / 0 has remainder -inf, not inf
1455 # +-inf / 0 => special case for -inf
1456 return wantarray ? ($x,$x->copy()) : $x if $x->is_inf();
1457 if (!$x->is_zero() && !$x->is_inf())
1459 my $t = $x->copy(); # binf clobbers up $x
1461 ($x->binf($x->{sign}),$t) : $x->binf($x->{sign})
1465 # last case: +-inf / ordinary number
1467 $sign = '-inf' if substr($x->{sign},0,1) ne $y->{sign};
1469 return wantarray ? ($x,$self->bzero()) : $x;
1474 # (dividend: BINT or num_str, divisor: BINT or num_str) return
1475 # (BINT,BINT) (quo,rem) or BINT (only rem)
1478 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1479 # objectify is costly, so avoid it
1480 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1482 ($self,$x,$y,@r) = objectify(2,@_);
1485 return $x if $x->modify('bdiv');
1487 return $self->_div_inf($x,$y)
1488 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero());
1490 return $upgrade->bdiv($upgrade->new($x),$upgrade->new($y),@r)
1491 if defined $upgrade;
1493 $r[3] = $y; # no push!
1495 # calc new sign and in case $y == +/- 1, return $x
1496 my $xsign = $x->{sign}; # keep
1497 $x->{sign} = ($x->{sign} ne $y->{sign} ? '-' : '+');
1501 my $rem = $self->bzero();
1502 ($x->{value},$rem->{value}) = $CALC->_div($x->{value},$y->{value});
1503 $x->{sign} = '+' if $CALC->_is_zero($x->{value});
1504 $rem->{_a} = $x->{_a};
1505 $rem->{_p} = $x->{_p};
1506 $x->round(@r) if !exists $x->{_f} || ($x->{_f} & MB_NEVER_ROUND) == 0;
1507 if (! $CALC->_is_zero($rem->{value}))
1509 $rem->{sign} = $y->{sign};
1510 $rem = $y->copy()->bsub($rem) if $xsign ne $y->{sign}; # one of them '-'
1514 $rem->{sign} = '+'; # dont leave -0
1516 $rem->round(@r) if !exists $rem->{_f} || ($rem->{_f} & MB_NEVER_ROUND) == 0;
1520 $x->{value} = $CALC->_div($x->{value},$y->{value});
1521 $x->{sign} = '+' if $CALC->_is_zero($x->{value});
1523 $x->round(@r) if !exists $x->{_f} || ($x->{_f} & MB_NEVER_ROUND) == 0;
1527 ###############################################################################
1532 # modulus (or remainder)
1533 # (BINT or num_str, BINT or num_str) return BINT
1536 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1537 # objectify is costly, so avoid it
1538 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1540 ($self,$x,$y,@r) = objectify(2,@_);
1543 return $x if $x->modify('bmod');
1544 $r[3] = $y; # no push!
1545 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero())
1547 my ($d,$r) = $self->_div_inf($x,$y);
1548 $x->{sign} = $r->{sign};
1549 $x->{value} = $r->{value};
1550 return $x->round(@r);
1553 if ($CALC->can('_mod'))
1555 # calc new sign and in case $y == +/- 1, return $x
1556 $x->{value} = $CALC->_mod($x->{value},$y->{value});
1557 if (!$CALC->_is_zero($x->{value}))
1559 my $xsign = $x->{sign};
1560 $x->{sign} = $y->{sign};
1561 if ($xsign ne $y->{sign})
1563 my $t = $CALC->_copy($x->{value}); # copy $x
1564 $x->{value} = $CALC->_copy($y->{value}); # copy $y to $x
1565 $x->{value} = $CALC->_sub($y->{value},$t,1); # $y-$x
1570 $x->{sign} = '+'; # dont leave -0
1572 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1575 my ($t,$rem) = $self->bdiv($x->copy(),$y,@r); # slow way (also rounds)
1577 foreach (qw/value sign _a _p/)
1579 $x->{$_} = $rem->{$_};
1586 # Modular inverse. given a number which is (hopefully) relatively
1587 # prime to the modulus, calculate its inverse using Euclid's
1588 # alogrithm. If the number is not relatively prime to the modulus
1589 # (i.e. their gcd is not one) then NaN is returned.
1592 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1593 # objectify is costly, so avoid it
1594 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1596 ($self,$x,$y,@r) = objectify(2,@_);
1599 return $x if $x->modify('bmodinv');
1602 if ($y->{sign} ne '+' # -, NaN, +inf, -inf
1603 || $x->is_zero() # or num == 0
1604 || $x->{sign} !~ /^[+-]$/ # or num NaN, inf, -inf
1607 # put least residue into $x if $x was negative, and thus make it positive
1608 $x->bmod($y) if $x->{sign} eq '-';
1610 if ($CALC->can('_modinv'))
1613 ($x->{value},$sign) = $CALC->_modinv($x->{value},$y->{value});
1614 $x->bnan() if !defined $x->{value}; # in case no GCD found
1615 return $x if !defined $sign; # already real result
1616 $x->{sign} = $sign; # flip/flop see below
1617 $x->bmod($y); # calc real result
1620 my ($u, $u1) = ($self->bzero(), $self->bone());
1621 my ($a, $b) = ($y->copy(), $x->copy());
1623 # first step need always be done since $num (and thus $b) is never 0
1624 # Note that the loop is aligned so that the check occurs between #2 and #1
1625 # thus saving us one step #2 at the loop end. Typical loop count is 1. Even
1626 # a case with 28 loops still gains about 3% with this layout.
1628 ($a, $q, $b) = ($b, $a->bdiv($b)); # step #1
1629 # Euclid's Algorithm (calculate GCD of ($a,$b) in $a and also calculate
1630 # two values in $u and $u1, we use only $u1 afterwards)
1631 my $sign = 1; # flip-flop
1632 while (!$b->is_zero()) # found GCD if $b == 0
1634 # the original algorithm had:
1635 # ($u, $u1) = ($u1, $u->bsub($u1->copy()->bmul($q))); # step #2
1636 # The following creates exact the same sequence of numbers in $u1,
1637 # except for the sign ($u1 is now always positive). Since formerly
1638 # the sign of $u1 was alternating between '-' and '+', the $sign
1639 # flip-flop will take care of that, so that at the end of the loop
1640 # we have the real sign of $u1. Keeping numbers positive gains us
1641 # speed since badd() is faster than bsub() and makes it possible
1642 # to have the algorithmn in Calc for even more speed.
1644 ($u, $u1) = ($u1, $u->badd($u1->copy()->bmul($q))); # step #2
1645 $sign = - $sign; # flip sign
1647 ($a, $q, $b) = ($b, $a->bdiv($b)); # step #1 again
1650 # If the gcd is not 1, then return NaN! It would be pointless to
1651 # have called bgcd to check this first, because we would then be
1652 # performing the same Euclidean Algorithm *twice*.
1653 return $x->bnan() unless $a->is_one();
1655 $u1->bneg() if $sign != 1; # need to flip?
1657 $u1->bmod($y); # calc result
1658 $x->{value} = $u1->{value}; # and copy over to $x
1659 $x->{sign} = $u1->{sign}; # to modify in place
1665 # takes a very large number to a very large exponent in a given very
1666 # large modulus, quickly, thanks to binary exponentation. supports
1667 # negative exponents.
1668 my ($self,$num,$exp,$mod,@r) = objectify(3,@_);
1670 return $num if $num->modify('bmodpow');
1672 # check modulus for valid values
1673 return $num->bnan() if ($mod->{sign} ne '+' # NaN, - , -inf, +inf
1674 || $mod->is_zero());
1676 # check exponent for valid values
1677 if ($exp->{sign} =~ /\w/)
1679 # i.e., if it's NaN, +inf, or -inf...
1680 return $num->bnan();
1683 $num->bmodinv ($mod) if ($exp->{sign} eq '-');
1685 # check num for valid values (also NaN if there was no inverse but $exp < 0)
1686 return $num->bnan() if $num->{sign} !~ /^[+-]$/;
1688 if ($CALC->can('_modpow'))
1690 # $mod is positive, sign on $exp is ignored, result also positive
1691 $num->{value} = $CALC->_modpow($num->{value},$exp->{value},$mod->{value});
1695 # in the trivial case,
1696 return $num->bzero(@r) if $mod->is_one();
1697 return $num->bone('+',@r) if $num->is_zero() or $num->is_one();
1699 # $num->bmod($mod); # if $x is large, make it smaller first
1700 my $acc = $num->copy(); # but this is not really faster...
1702 $num->bone(); # keep ref to $num
1704 my $expbin = $exp->as_bin(); $expbin =~ s/^[-]?0b//; # ignore sign and prefix
1705 my $len = CORE::length($expbin);
1708 if( substr($expbin,$len,1) eq '1')
1710 $num->bmul($acc)->bmod($mod);
1712 $acc->bmul($acc)->bmod($mod);
1718 ###############################################################################
1722 # (BINT or num_str, BINT or num_str) return BINT
1723 # compute factorial numbers
1724 # modifies first argument
1725 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1727 return $x if $x->modify('bfac');
1729 return $x->bnan() if $x->{sign} ne '+'; # inf, NnN, <0 etc => NaN
1730 return $x->bone('+',@r) if $x->is_zero() || $x->is_one(); # 0 or 1 => 1
1732 if ($CALC->can('_fac'))
1734 $x->{value} = $CALC->_fac($x->{value});
1735 return $x->round(@r);
1740 # seems we need not to temp. clear A/P of $x since the result is the same
1741 my $f = $self->new(2);
1742 while ($f->bacmp($n) < 0)
1744 $x->bmul($f); $f->binc();
1746 $x->bmul($f,@r); # last step and also round
1751 # (BINT or num_str, BINT or num_str) return BINT
1752 # compute power of two numbers -- stolen from Knuth Vol 2 pg 233
1753 # modifies first argument
1756 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1757 # objectify is costly, so avoid it
1758 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1760 ($self,$x,$y,@r) = objectify(2,@_);
1763 return $x if $x->modify('bpow');
1765 return $upgrade->bpow($upgrade->new($x),$y,@r)
1766 if defined $upgrade && !$y->isa($self);
1768 $r[3] = $y; # no push!
1769 return $x if $x->{sign} =~ /^[+-]inf$/; # -inf/+inf ** x
1770 return $x->bnan() if $x->{sign} eq $nan || $y->{sign} eq $nan;
1771 return $x->bone('+',@r) if $y->is_zero();
1772 return $x->round(@r) if $x->is_one() || $y->is_one();
1773 if ($x->{sign} eq '-' && $CALC->_is_one($x->{value}))
1775 # if $x == -1 and odd/even y => +1/-1
1776 return $y->is_odd() ? $x->round(@r) : $x->babs()->round(@r);
1777 # my Casio FX-5500L has a bug here: -1 ** 2 is -1, but -1 * -1 is 1;
1779 # 1 ** -y => 1 / (1 ** |y|)
1780 # so do test for negative $y after above's clause
1781 return $x->bnan() if $y->{sign} eq '-';
1782 return $x->round(@r) if $x->is_zero(); # 0**y => 0 (if not y <= 0)
1784 if ($CALC->can('_pow'))
1786 $x->{value} = $CALC->_pow($x->{value},$y->{value});
1787 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1791 # based on the assumption that shifting in base 10 is fast, and that mul
1792 # works faster if numbers are small: we count trailing zeros (this step is
1793 # O(1)..O(N), but in case of O(N) we save much more time due to this),
1794 # stripping them out of the multiplication, and add $count * $y zeros
1795 # afterwards like this:
1796 # 300 ** 3 == 300*300*300 == 3*3*3 . '0' x 2 * 3 == 27 . '0' x 6
1797 # creates deep recursion since brsft/blsft use bpow sometimes.
1798 # my $zeros = $x->_trailing_zeros();
1801 # $x->brsft($zeros,10); # remove zeros
1802 # $x->bpow($y); # recursion (will not branch into here again)
1803 # $zeros = $y * $zeros; # real number of zeros to add
1804 # $x->blsft($zeros,10);
1805 # return $x->round(@r);
1808 my $pow2 = $self->__one();
1809 my $y_bin = $y->as_bin(); $y_bin =~ s/^0b//;
1810 my $len = CORE::length($y_bin);
1813 $pow2->bmul($x) if substr($y_bin,$len,1) eq '1'; # is odd?
1817 $x->round(@r) if !exists $x->{_f} || $x->{_f} & MB_NEVER_ROUND == 0;
1823 # (BINT or num_str, BINT or num_str) return BINT
1824 # compute x << y, base n, y >= 0
1827 my ($self,$x,$y,$n,@r) = (ref($_[0]),@_);
1828 # objectify is costly, so avoid it
1829 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1831 ($self,$x,$y,$n,@r) = objectify(2,@_);
1834 return $x if $x->modify('blsft');
1835 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1836 return $x->round(@r) if $y->is_zero();
1838 $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
1840 my $t; $t = $CALC->_lsft($x->{value},$y->{value},$n) if $CALC->can('_lsft');
1843 $x->{value} = $t; return $x->round(@r);
1846 return $x->bmul( $self->bpow($n, $y, @r), @r );
1851 # (BINT or num_str, BINT or num_str) return BINT
1852 # compute x >> y, base n, y >= 0
1855 my ($self,$x,$y,$n,@r) = (ref($_[0]),@_);
1856 # objectify is costly, so avoid it
1857 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1859 ($self,$x,$y,$n,@r) = objectify(2,@_);
1862 return $x if $x->modify('brsft');
1863 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1864 return $x->round(@r) if $y->is_zero();
1865 return $x->bzero(@r) if $x->is_zero(); # 0 => 0
1867 $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
1869 # this only works for negative numbers when shifting in base 2
1870 if (($x->{sign} eq '-') && ($n == 2))
1872 return $x->round(@r) if $x->is_one('-'); # -1 => -1
1875 # although this is O(N*N) in calc (as_bin!) it is O(N) in Pari et al
1876 # but perhaps there is a better emulation for two's complement shift...
1877 # if $y != 1, we must simulate it by doing:
1878 # convert to bin, flip all bits, shift, and be done
1879 $x->binc(); # -3 => -2
1880 my $bin = $x->as_bin();
1881 $bin =~ s/^-0b//; # strip '-0b' prefix
1882 $bin =~ tr/10/01/; # flip bits
1884 if (CORE::length($bin) <= $y)
1886 $bin = '0'; # shifting to far right creates -1
1887 # 0, because later increment makes
1888 # that 1, attached '-' makes it '-1'
1889 # because -1 >> x == -1 !
1893 $bin =~ s/.{$y}$//; # cut off at the right side
1894 $bin = '1' . $bin; # extend left side by one dummy '1'
1895 $bin =~ tr/10/01/; # flip bits back
1897 my $res = $self->new('0b'.$bin); # add prefix and convert back
1898 $res->binc(); # remember to increment
1899 $x->{value} = $res->{value}; # take over value
1900 return $x->round(@r); # we are done now, magic, isn't?
1902 $x->bdec(); # n == 2, but $y == 1: this fixes it
1905 my $t; $t = $CALC->_rsft($x->{value},$y->{value},$n) if $CALC->can('_rsft');
1909 return $x->round(@r);
1912 $x->bdiv($self->bpow($n,$y, @r), @r);
1918 #(BINT or num_str, BINT or num_str) return BINT
1922 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1923 # objectify is costly, so avoid it
1924 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1926 ($self,$x,$y,@r) = objectify(2,@_);
1929 return $x if $x->modify('band');
1931 $r[3] = $y; # no push!
1932 local $Math::BigInt::upgrade = undef;
1934 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1935 return $x->bzero(@r) if $y->is_zero() || $x->is_zero();
1937 my $sign = 0; # sign of result
1938 $sign = 1 if ($x->{sign} eq '-') && ($y->{sign} eq '-');
1939 my $sx = 1; $sx = -1 if $x->{sign} eq '-';
1940 my $sy = 1; $sy = -1 if $y->{sign} eq '-';
1942 if ($CALC->can('_and') && $sx == 1 && $sy == 1)
1944 $x->{value} = $CALC->_and($x->{value},$y->{value});
1945 return $x->round(@r);
1948 my $m = $self->bone(); my ($xr,$yr);
1949 my $x10000 = $self->new (0x1000);
1950 my $y1 = copy(ref($x),$y); # make copy
1951 $y1->babs(); # and positive
1952 my $x1 = $x->copy()->babs(); $x->bzero(); # modify x in place!
1953 use integer; # need this for negative bools
1954 while (!$x1->is_zero() && !$y1->is_zero())
1956 ($x1, $xr) = bdiv($x1, $x10000);
1957 ($y1, $yr) = bdiv($y1, $x10000);
1958 # make both op's numbers!
1959 $x->badd( bmul( $class->new(
1960 abs($sx*int($xr->numify()) & $sy*int($yr->numify()))),
1964 $x->bneg() if $sign;
1970 #(BINT or num_str, BINT or num_str) return BINT
1974 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1975 # objectify is costly, so avoid it
1976 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1978 ($self,$x,$y,@r) = objectify(2,@_);
1981 return $x if $x->modify('bior');
1982 $r[3] = $y; # no push!
1984 local $Math::BigInt::upgrade = undef;
1986 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1987 return $x->round(@r) if $y->is_zero();
1989 my $sign = 0; # sign of result
1990 $sign = 1 if ($x->{sign} eq '-') || ($y->{sign} eq '-');
1991 my $sx = 1; $sx = -1 if $x->{sign} eq '-';
1992 my $sy = 1; $sy = -1 if $y->{sign} eq '-';
1994 # don't use lib for negative values
1995 if ($CALC->can('_or') && $sx == 1 && $sy == 1)
1997 $x->{value} = $CALC->_or($x->{value},$y->{value});
1998 return $x->round(@r);
2001 my $m = $self->bone(); my ($xr,$yr);
2002 my $x10000 = $self->new(0x10000);
2003 my $y1 = copy(ref($x),$y); # make copy
2004 $y1->babs(); # and positive
2005 my $x1 = $x->copy()->babs(); $x->bzero(); # modify x in place!
2006 use integer; # need this for negative bools
2007 while (!$x1->is_zero() || !$y1->is_zero())
2009 ($x1, $xr) = bdiv($x1,$x10000);
2010 ($y1, $yr) = bdiv($y1,$x10000);
2011 # make both op's numbers!
2012 $x->badd( bmul( $class->new(
2013 abs($sx*int($xr->numify()) | $sy*int($yr->numify()))),
2017 $x->bneg() if $sign;
2023 #(BINT or num_str, BINT or num_str) return BINT
2027 my ($self,$x,$y,@r) = (ref($_[0]),@_);
2028 # objectify is costly, so avoid it
2029 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
2031 ($self,$x,$y,@r) = objectify(2,@_);
2034 return $x if $x->modify('bxor');
2035 $r[3] = $y; # no push!
2037 local $Math::BigInt::upgrade = undef;
2039 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
2040 return $x->round(@r) if $y->is_zero();
2042 my $sign = 0; # sign of result
2043 $sign = 1 if $x->{sign} ne $y->{sign};
2044 my $sx = 1; $sx = -1 if $x->{sign} eq '-';
2045 my $sy = 1; $sy = -1 if $y->{sign} eq '-';
2047 # don't use lib for negative values
2048 if ($CALC->can('_xor') && $sx == 1 && $sy == 1)
2050 $x->{value} = $CALC->_xor($x->{value},$y->{value});
2051 return $x->round(@r);
2054 my $m = $self->bone(); my ($xr,$yr);
2055 my $x10000 = $self->new(0x10000);
2056 my $y1 = copy(ref($x),$y); # make copy
2057 $y1->babs(); # and positive
2058 my $x1 = $x->copy()->babs(); $x->bzero(); # modify x in place!
2059 use integer; # need this for negative bools
2060 while (!$x1->is_zero() || !$y1->is_zero())
2062 ($x1, $xr) = bdiv($x1, $x10000);
2063 ($y1, $yr) = bdiv($y1, $x10000);
2064 # make both op's numbers!
2065 $x->badd( bmul( $class->new(
2066 abs($sx*int($xr->numify()) ^ $sy*int($yr->numify()))),
2070 $x->bneg() if $sign;
2076 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2078 my $e = $CALC->_len($x->{value});
2079 return wantarray ? ($e,0) : $e;
2084 # return the nth decimal digit, negative values count backward, 0 is right
2085 my ($self,$x,$n) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
2087 $CALC->_digit($x->{value},$n||0);
2092 # return the amount of trailing zeros in $x
2094 $x = $class->new($x) unless ref $x;
2096 return 0 if $x->is_zero() || $x->is_odd() || $x->{sign} !~ /^[+-]$/;
2098 return $CALC->_zeros($x->{value}) if $CALC->can('_zeros');
2100 # if not: since we do not know underlying internal representation:
2101 my $es = "$x"; $es =~ /([0]*)$/;
2102 return 0 if !defined $1; # no zeros
2103 CORE::length("$1"); # as string, not as +0!
2108 # calculate square root of $x
2109 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
2111 return $x if $x->modify('bsqrt');
2113 return $x->bnan() if $x->{sign} !~ /^\+/; # -x or -inf or NaN => NaN
2114 return $x if $x->{sign} eq '+inf'; # sqrt(+inf) == inf
2115 return $x->round(@r) if $x->is_zero() || $x->is_one(); # 0,1 => 0,1
2117 return $upgrade->bsqrt($x,@r) if defined $upgrade;
2119 if ($CALC->can('_sqrt'))
2121 $x->{value} = $CALC->_sqrt($x->{value});
2122 return $x->round(@r);
2125 return $x->bone('+',@r) if $x < 4; # 2,3 => 1
2127 my $l = int($x->length()/2);
2129 $x->bone(); # keep ref($x), but modify it
2130 $x->blsft($l,10) if $l != 0; # first guess: 1.('0' x (l/2))
2132 my $last = $self->bzero();
2133 my $two = $self->new(2);
2134 my $lastlast = $self->bzero();
2135 #my $lastlast = $x+$two;
2136 while ($last != $x && $lastlast != $x)
2138 $lastlast = $last; $last = $x->copy();
2142 $x->bdec() if $x * $x > $y; # overshot?
2148 # calculate $y'th root of $x
2151 my ($self,$x,$y,@r) = (ref($_[0]),@_);
2153 $y = $self->new(2) unless defined $y;
2155 # objectify is costly, so avoid it
2156 if ((!ref($x)) || (ref($x) ne ref($y)))
2158 ($self,$x,$y,@r) = $self->objectify(2,@_);
2161 return $x if $x->modify('broot');
2163 # NaN handling: $x ** 1/0, x or y NaN, or y inf/-inf or y == 0
2164 return $x->bnan() if $x->{sign} !~ /^\+/ || $y->is_zero() ||
2165 $y->{sign} !~ /^\+$/;
2167 return $x->round(@r)
2168 if $x->is_zero() || $x->is_one() || $x->is_inf() || $y->is_one();
2170 return $upgrade->new($x)->broot($upgrade->new($y),@r) if defined $upgrade;
2172 if ($CALC->can('_root'))
2174 $x->{value} = $CALC->_root($x->{value},$y->{value});
2175 return $x->round(@r);
2178 return $x->bsqrt() if $y->bacmp(2) == 0; # 2 => square root
2180 # since we take at least a cubic root, and only 8 ** 1/3 >= 2 (==2):
2181 return $x->bone('+',@r) if $x < 8; # $x=2..7 => 1
2183 my $num = $x->numify();
2185 if ($num <= 1000000)
2187 $x = $self->new( int($num ** (1 / $y->numify()) ));
2188 return $x->round(@r);
2191 # if $n is a power of two, we can repeatedly take sqrt($X) and find the
2192 # proper result, because sqrt(sqrt($x)) == root($x,4)
2193 # See Calc.pm for more details
2194 my $b = $y->as_bin();
2195 if ($b =~ /0b1(0+)/)
2197 my $count = CORE::length($1); # 0b100 => len('00') => 2
2198 my $cnt = $count; # counter for loop
2199 my $shift = $self->new(6);
2200 $x->blsft($shift); # add some zeros (even amount)
2203 # 'inflate' $X by adding more zeros
2205 # calculate sqrt($x), $x is now a bit too big, again. In the next
2206 # round we make even bigger, again.
2209 # $x is still to big, so truncate result
2214 # Should compute a guess of the result (by rule of thumb), then improve it
2215 # via Newton's method or something similiar.
2217 warn ('broot() not fully implemented in BigInt.');
2219 return $x->round(@r);
2224 # return a copy of the exponent (here always 0, NaN or 1 for $m == 0)
2225 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2227 if ($x->{sign} !~ /^[+-]$/)
2229 my $s = $x->{sign}; $s =~ s/^[+-]//;
2230 return $self->new($s); # -inf,+inf => inf
2232 my $e = $class->bzero();
2233 return $e->binc() if $x->is_zero();
2234 $e += $x->_trailing_zeros();
2240 # return the mantissa (compatible to Math::BigFloat, e.g. reduced)
2241 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2243 if ($x->{sign} !~ /^[+-]$/)
2245 return $self->new($x->{sign}); # keep + or - sign
2248 # that's inefficient
2249 my $zeros = $m->_trailing_zeros();
2250 $m->brsft($zeros,10) if $zeros != 0;
2256 # return a copy of both the exponent and the mantissa
2257 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2259 return ($x->mantissa(),$x->exponent());
2262 ##############################################################################
2263 # rounding functions
2267 # precision: round to the $Nth digit left (+$n) or right (-$n) from the '.'
2268 # $n == 0 || $n == 1 => round to integer
2269 my $x = shift; $x = $class->new($x) unless ref $x;
2270 my ($scale,$mode) = $x->_scale_p($x->precision(),$x->round_mode(),@_);
2271 return $x if !defined $scale; # no-op
2272 return $x if $x->modify('bfround');
2274 # no-op for BigInts if $n <= 0
2277 $x->{_a} = undef; # clear an eventual set A
2278 $x->{_p} = $scale; return $x;
2281 $x->bround( $x->length()-$scale, $mode);
2282 $x->{_a} = undef; # bround sets {_a}
2283 $x->{_p} = $scale; # so correct it
2287 sub _scan_for_nonzero
2293 my $len = $x->length();
2294 return 0 if $len == 1; # '5' is trailed by invisible zeros
2295 my $follow = $pad - 1;
2296 return 0 if $follow > $len || $follow < 1;
2298 # since we do not know underlying represention of $x, use decimal string
2299 #my $r = substr ($$xs,-$follow);
2300 my $r = substr ("$x",-$follow);
2301 return 1 if $r =~ /[^0]/;
2307 # to make life easier for switch between MBF and MBI (autoload fxxx()
2308 # like MBF does for bxxx()?)
2310 return $x->bround(@_);
2315 # accuracy: +$n preserve $n digits from left,
2316 # -$n preserve $n digits from right (f.i. for 0.1234 style in MBF)
2318 # and overwrite the rest with 0's, return normalized number
2319 # do not return $x->bnorm(), but $x
2321 my $x = shift; $x = $class->new($x) unless ref $x;
2322 my ($scale,$mode) = $x->_scale_a($x->accuracy(),$x->round_mode(),@_);
2323 return $x if !defined $scale; # no-op
2324 return $x if $x->modify('bround');
2326 if ($x->is_zero() || $scale == 0)
2328 $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale; # 3 > 2
2331 return $x if $x->{sign} !~ /^[+-]$/; # inf, NaN
2333 # we have fewer digits than we want to scale to
2334 my $len = $x->length();
2335 # convert $scale to a scalar in case it is an object (put's a limit on the
2336 # number length, but this would already limited by memory constraints), makes
2338 $scale = $scale->numify() if ref ($scale);
2340 # scale < 0, but > -len (not >=!)
2341 if (($scale < 0 && $scale < -$len-1) || ($scale >= $len))
2343 $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale; # 3 > 2
2347 # count of 0's to pad, from left (+) or right (-): 9 - +6 => 3, or |-6| => 6
2348 my ($pad,$digit_round,$digit_after);
2349 $pad = $len - $scale;
2350 $pad = abs($scale-1) if $scale < 0;
2352 # do not use digit(), it is costly for binary => decimal
2354 my $xs = $CALC->_str($x->{value});
2357 # pad: 123: 0 => -1, at 1 => -2, at 2 => -3, at 3 => -4
2358 # pad+1: 123: 0 => 0, at 1 => -1, at 2 => -2, at 3 => -3
2359 $digit_round = '0'; $digit_round = substr($$xs,$pl,1) if $pad <= $len;
2360 $pl++; $pl ++ if $pad >= $len;
2361 $digit_after = '0'; $digit_after = substr($$xs,$pl,1) if $pad > 0;
2363 # in case of 01234 we round down, for 6789 up, and only in case 5 we look
2364 # closer at the remaining digits of the original $x, remember decision
2365 my $round_up = 1; # default round up
2367 ($mode eq 'trunc') || # trunc by round down
2368 ($digit_after =~ /[01234]/) || # round down anyway,
2370 ($digit_after eq '5') && # not 5000...0000
2371 ($x->_scan_for_nonzero($pad,$xs) == 0) &&
2373 ($mode eq 'even') && ($digit_round =~ /[24680]/) ||
2374 ($mode eq 'odd') && ($digit_round =~ /[13579]/) ||
2375 ($mode eq '+inf') && ($x->{sign} eq '-') ||
2376 ($mode eq '-inf') && ($x->{sign} eq '+') ||
2377 ($mode eq 'zero') # round down if zero, sign adjusted below
2379 my $put_back = 0; # not yet modified
2381 if (($pad > 0) && ($pad <= $len))
2383 substr($$xs,-$pad,$pad) = '0' x $pad;
2388 $x->bzero(); # round to '0'
2391 if ($round_up) # what gave test above?
2394 $pad = $len, $$xs = '0' x $pad if $scale < 0; # tlr: whack 0.51=>1.0
2396 # we modify directly the string variant instead of creating a number and
2397 # adding it, since that is faster (we already have the string)
2398 my $c = 0; $pad ++; # for $pad == $len case
2399 while ($pad <= $len)
2401 $c = substr($$xs,-$pad,1) + 1; $c = '0' if $c eq '10';
2402 substr($$xs,-$pad,1) = $c; $pad++;
2403 last if $c != 0; # no overflow => early out
2405 $$xs = '1'.$$xs if $c == 0;
2408 $x->{value} = $CALC->_new($xs) if $put_back == 1; # put back in if needed
2410 $x->{_a} = $scale if $scale >= 0;
2413 $x->{_a} = $len+$scale;
2414 $x->{_a} = 0 if $scale < -$len;
2421 # return integer less or equal then number, since it is already integer,
2422 # always returns $self
2423 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
2430 # return integer greater or equal then number, since it is already integer,
2431 # always returns $self
2432 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
2437 ##############################################################################
2438 # private stuff (internal use only)
2442 # internal speedup, set argument to 1, or create a +/- 1
2444 my $x = $self->bone(); # $x->{value} = $CALC->_one();
2445 $x->{sign} = shift || '+';
2451 # Overload will swap params if first one is no object ref so that the first
2452 # one is always an object ref. In this case, third param is true.
2453 # This routine is to overcome the effect of scalar,$object creating an object
2454 # of the class of this package, instead of the second param $object. This
2455 # happens inside overload, when the overload section of this package is
2456 # inherited by sub classes.
2457 # For overload cases (and this is used only there), we need to preserve the
2458 # args, hence the copy().
2459 # You can override this method in a subclass, the overload section will call
2460 # $object->_swap() to make sure it arrives at the proper subclass, with some
2461 # exceptions like '+' and '-'. To make '+' and '-' work, you also need to
2462 # specify your own overload for them.
2464 # object, (object|scalar) => preserve first and make copy
2465 # scalar, object => swapped, re-swap and create new from first
2466 # (using class of second object, not $class!!)
2467 my $self = shift; # for override in subclass
2470 my $c = ref ($_[0]) || $class; # fallback $class should not happen
2471 return ( $c->new($_[1]), $_[0] );
2473 return ( $_[0]->copy(), $_[1] );
2478 # check for strings, if yes, return objects instead
2480 # the first argument is number of args objectify() should look at it will
2481 # return $count+1 elements, the first will be a classname. This is because
2482 # overloaded '""' calls bstr($object,undef,undef) and this would result in
2483 # useless objects beeing created and thrown away. So we cannot simple loop
2484 # over @_. If the given count is 0, all arguments will be used.
2486 # If the second arg is a ref, use it as class.
2487 # If not, try to use it as classname, unless undef, then use $class
2488 # (aka Math::BigInt). The latter shouldn't happen,though.
2491 # $x->badd(1); => ref x, scalar y
2492 # Class->badd(1,2); => classname x (scalar), scalar x, scalar y
2493 # Class->badd( Class->(1),2); => classname x (scalar), ref x, scalar y
2494 # Math::BigInt::badd(1,2); => scalar x, scalar y
2495 # In the last case we check number of arguments to turn it silently into
2496 # $class,1,2. (We can not take '1' as class ;o)
2497 # badd($class,1) is not supported (it should, eventually, try to add undef)
2498 # currently it tries 'Math::BigInt' + 1, which will not work.
2500 # some shortcut for the common cases
2502 return (ref($_[1]),$_[1]) if (@_ == 2) && ($_[0]||0 == 1) && ref($_[1]);
2504 my $count = abs(shift || 0);
2506 my (@a,$k,$d); # resulting array, temp, and downgrade
2509 # okay, got object as first
2514 # nope, got 1,2 (Class->xxx(1) => Class,1 and not supported)
2516 $a[0] = shift if $_[0] =~ /^[A-Z].*::/; # classname as first?
2520 # disable downgrading, because Math::BigFLoat->foo('1.0','2.0') needs floats
2521 if (defined ${"$a[0]::downgrade"})
2523 $d = ${"$a[0]::downgrade"};
2524 ${"$a[0]::downgrade"} = undef;
2527 my $up = ${"$a[0]::upgrade"};
2528 #print "Now in objectify, my class is today $a[0], count = $count\n";
2536 $k = $a[0]->new($k);
2538 elsif (!defined $up && ref($k) ne $a[0])
2540 # foreign object, try to convert to integer
2541 $k->can('as_number') ? $k = $k->as_number() : $k = $a[0]->new($k);
2554 $k = $a[0]->new($k);
2556 elsif (!defined $up && ref($k) ne $a[0])
2558 # foreign object, try to convert to integer
2559 $k->can('as_number') ? $k = $k->as_number() : $k = $a[0]->new($k);
2563 push @a,@_; # return other params, too
2567 require Carp; Carp::croak ("$class objectify needs list context");
2569 ${"$a[0]::downgrade"} = $d;
2578 my @a; my $l = scalar @_;
2579 for ( my $i = 0; $i < $l ; $i++ )
2581 if ($_[$i] eq ':constant')
2583 # this causes overlord er load to step in
2584 overload::constant integer => sub { $self->new(shift) };
2585 overload::constant binary => sub { $self->new(shift) };
2587 elsif ($_[$i] eq 'upgrade')
2589 # this causes upgrading
2590 $upgrade = $_[$i+1]; # or undef to disable
2593 elsif ($_[$i] =~ /^lib$/i)
2595 # this causes a different low lib to take care...
2596 $CALC = $_[$i+1] || '';
2604 # any non :constant stuff is handled by our parent, Exporter
2605 # even if @_ is empty, to give it a chance
2606 $self->SUPER::import(@a); # need it for subclasses
2607 $self->export_to_level(1,$self,@a); # need it for MBF
2609 # try to load core math lib
2610 my @c = split /\s*,\s*/,$CALC;
2611 push @c,'Calc'; # if all fail, try this
2612 $CALC = ''; # signal error
2613 foreach my $lib (@c)
2615 next if ($lib || '') eq '';
2616 $lib = 'Math::BigInt::'.$lib if $lib !~ /^Math::BigInt/i;
2620 # Perl < 5.6.0 dies with "out of memory!" when eval() and ':constant' is
2621 # used in the same script, or eval inside import().
2622 my @parts = split /::/, $lib; # Math::BigInt => Math BigInt
2623 my $file = pop @parts; $file .= '.pm'; # BigInt => BigInt.pm
2625 $file = File::Spec->catfile (@parts, $file);
2626 eval { require "$file"; $lib->import( @c ); }
2630 eval "use $lib qw/@c/;";
2632 $CALC = $lib, last if $@ eq ''; # no error in loading lib?
2637 Carp::croak ("Couldn't load any math lib, not even the default");
2643 # convert a (ref to) big hex string to BigInt, return undef for error
2646 my $x = Math::BigInt->bzero();
2649 $$hs =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
2650 $$hs =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
2652 return $x->bnan() if $$hs !~ /^[\-\+]?0x[0-9A-Fa-f]+$/;
2654 my $sign = '+'; $sign = '-' if ($$hs =~ /^-/);
2656 $$hs =~ s/^[+-]//; # strip sign
2657 if ($CALC->can('_from_hex'))
2659 $x->{value} = $CALC->_from_hex($hs);
2663 # fallback to pure perl
2664 my $mul = Math::BigInt->bzero(); $mul++;
2665 my $x65536 = Math::BigInt->new(65536);
2666 my $len = CORE::length($$hs)-2;
2667 $len = int($len/4); # 4-digit parts, w/o '0x'
2668 my $val; my $i = -4;
2671 $val = substr($$hs,$i,4);
2672 $val =~ s/^[+-]?0x// if $len == 0; # for last part only because
2673 $val = hex($val); # hex does not like wrong chars
2675 $x += $mul * $val if $val != 0;
2676 $mul *= $x65536 if $len >= 0; # skip last mul
2679 $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
2685 # convert a (ref to) big binary string to BigInt, return undef for error
2688 my $x = Math::BigInt->bzero();
2690 $$bs =~ s/([01])_([01])/$1$2/g;
2691 $$bs =~ s/([01])_([01])/$1$2/g;
2692 return $x->bnan() if $$bs !~ /^[+-]?0b[01]+$/;
2694 my $sign = '+'; $sign = '-' if ($$bs =~ /^\-/);
2695 $$bs =~ s/^[+-]//; # strip sign
2696 if ($CALC->can('_from_bin'))
2698 $x->{value} = $CALC->_from_bin($bs);
2702 my $mul = Math::BigInt->bzero(); $mul++;
2703 my $x256 = Math::BigInt->new(256);
2704 my $len = CORE::length($$bs)-2;
2705 $len = int($len/8); # 8-digit parts, w/o '0b'
2706 my $val; my $i = -8;
2709 $val = substr($$bs,$i,8);
2710 $val =~ s/^[+-]?0b// if $len == 0; # for last part only
2711 #$val = oct('0b'.$val); # does not work on Perl prior to 5.6.0
2713 # $val = ('0' x (8-CORE::length($val))).$val if CORE::length($val) < 8;
2714 $val = ord(pack('B8',substr('00000000'.$val,-8,8)));
2716 $x += $mul * $val if $val != 0;
2717 $mul *= $x256 if $len >= 0; # skip last mul
2720 $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
2726 # (ref to num_str) return num_str
2727 # internal, take apart a string and return the pieces
2728 # strip leading/trailing whitespace, leading zeros, underscore and reject
2732 # strip white space at front, also extranous leading zeros
2733 $$x =~ s/^\s*([-]?)0*([0-9])/$1$2/g; # will not strip ' .2'
2734 $$x =~ s/^\s+//; # but this will
2735 $$x =~ s/\s+$//g; # strip white space at end
2737 # shortcut, if nothing to split, return early
2738 if ($$x =~ /^[+-]?\d+\z/)
2740 $$x =~ s/^([+-])0*([0-9])/$2/; my $sign = $1 || '+';
2741 return (\$sign, $x, \'', \'', \0);
2744 # invalid starting char?
2745 return if $$x !~ /^[+-]?(\.?[0-9]|0b[0-1]|0x[0-9a-fA-F])/;
2747 return __from_hex($x) if $$x =~ /^[\-\+]?0x/; # hex string
2748 return __from_bin($x) if $$x =~ /^[\-\+]?0b/; # binary string
2750 # strip underscores between digits
2751 $$x =~ s/(\d)_(\d)/$1$2/g;
2752 $$x =~ s/(\d)_(\d)/$1$2/g; # do twice for 1_2_3
2754 # some possible inputs:
2755 # 2.1234 # 0.12 # 1 # 1E1 # 2.134E1 # 434E-10 # 1.02009E-2
2756 # .2 # 1_2_3.4_5_6 # 1.4E1_2_3 # 1e3 # +.2 # 0e999
2758 #return if $$x =~ /[Ee].*[Ee]/; # more than one E => error
2760 my ($m,$e,$last) = split /[Ee]/,$$x;
2761 return if defined $last; # last defined => 1e2E3 or others
2762 $e = '0' if !defined $e || $e eq "";
2764 # sign,value for exponent,mantint,mantfrac
2765 my ($es,$ev,$mis,$miv,$mfv);
2767 if ($e =~ /^([+-]?)0*(\d+)$/) # strip leading zeros
2771 return if $m eq '.' || $m eq '';
2772 my ($mi,$mf,$lastf) = split /\./,$m;
2773 return if defined $lastf; # last defined => 1.2.3 or others
2774 $mi = '0' if !defined $mi;
2775 $mi .= '0' if $mi =~ /^[\-\+]?$/;
2776 $mf = '0' if !defined $mf || $mf eq '';
2777 if ($mi =~ /^([+-]?)0*(\d+)$/) # strip leading zeros
2779 $mis = $1||'+'; $miv = $2;
2780 return unless ($mf =~ /^(\d*?)0*$/); # strip trailing zeros
2782 # handle the 0e999 case here
2783 $ev = 0 if $miv eq '0' && $mfv eq '';
2784 return (\$mis,\$miv,\$mfv,\$es,\$ev);
2787 return; # NaN, not a number
2792 # an object might be asked to return itself as bigint on certain overloaded
2793 # operations, this does exactly this, so that sub classes can simple inherit
2794 # it or override with their own integer conversion routine
2802 # return as hex string, with prefixed 0x
2803 my $x = shift; $x = $class->new($x) if !ref($x);
2805 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2807 my $es = ''; my $s = '';
2808 $s = $x->{sign} if $x->{sign} eq '-';
2809 if ($CALC->can('_as_hex'))
2811 $es = ${$CALC->_as_hex($x->{value})};
2815 return '0x0' if $x->is_zero();
2817 my $x1 = $x->copy()->babs(); my ($xr,$x10000,$h);
2820 $x10000 = Math::BigInt->new (0x10000); $h = 'h4';
2824 $x10000 = Math::BigInt->new (0x1000); $h = 'h3';
2826 while (!$x1->is_zero())
2828 ($x1, $xr) = bdiv($x1,$x10000);
2829 $es .= unpack($h,pack('v',$xr->numify()));
2832 $es =~ s/^[0]+//; # strip leading zeros
2840 # return as binary string, with prefixed 0b
2841 my $x = shift; $x = $class->new($x) if !ref($x);
2843 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2845 my $es = ''; my $s = '';
2846 $s = $x->{sign} if $x->{sign} eq '-';
2847 if ($CALC->can('_as_bin'))
2849 $es = ${$CALC->_as_bin($x->{value})};
2853 return '0b0' if $x->is_zero();
2854 my $x1 = $x->copy()->babs(); my ($xr,$x10000,$b);
2857 $x10000 = Math::BigInt->new (0x10000); $b = 'b16';
2861 $x10000 = Math::BigInt->new (0x1000); $b = 'b12';
2863 while (!$x1->is_zero())
2865 ($x1, $xr) = bdiv($x1,$x10000);
2866 $es .= unpack($b,pack('v',$xr->numify()));
2869 $es =~ s/^[0]+//; # strip leading zeros
2875 ##############################################################################
2876 # internal calculation routines (others are in Math::BigInt::Calc etc)
2880 # (BINT or num_str, BINT or num_str) return BINT
2881 # does modify first argument
2884 my $x = shift; my $ty = shift;
2885 return $x->bnan() if ($x->{sign} eq $nan) || ($ty->{sign} eq $nan);
2886 return $x * $ty / bgcd($x,$ty);
2891 # (BINT or num_str, BINT or num_str) return BINT
2892 # does modify both arguments
2893 # GCD -- Euclids algorithm E, Knuth Vol 2 pg 296
2896 return $x->bnan() if $x->{sign} !~ /^[+-]$/ || $ty->{sign} !~ /^[+-]$/;
2898 while (!$ty->is_zero())
2900 ($x, $ty) = ($ty,bmod($x,$ty));
2905 ###############################################################################
2906 # this method return 0 if the object can be modified, or 1 for not
2907 # We use a fast use constant statement here, to avoid costly calls. Subclasses
2908 # may override it with special code (f.i. Math::BigInt::Constant does so)
2910 sub modify () { 0; }
2917 Math::BigInt - Arbitrary size integer math package
2923 # or make it faster: install (optional) Math::BigInt::GMP
2924 # and always use (it will fall back to pure Perl if the
2925 # GMP library is not installed):
2927 use Math::BigInt lib => 'GMP';
2930 $x = Math::BigInt->new($str); # defaults to 0
2931 $nan = Math::BigInt->bnan(); # create a NotANumber
2932 $zero = Math::BigInt->bzero(); # create a +0
2933 $inf = Math::BigInt->binf(); # create a +inf
2934 $inf = Math::BigInt->binf('-'); # create a -inf
2935 $one = Math::BigInt->bone(); # create a +1
2936 $one = Math::BigInt->bone('-'); # create a -1
2938 # Testing (don't modify their arguments)
2939 # (return true if the condition is met, otherwise false)
2941 $x->is_zero(); # if $x is +0
2942 $x->is_nan(); # if $x is NaN
2943 $x->is_one(); # if $x is +1
2944 $x->is_one('-'); # if $x is -1
2945 $x->is_odd(); # if $x is odd
2946 $x->is_even(); # if $x is even
2947 $x->is_positive(); # if $x >= 0
2948 $x->is_negative(); # if $x < 0
2949 $x->is_inf(sign); # if $x is +inf, or -inf (sign is default '+')
2950 $x->is_int(); # if $x is an integer (not a float)
2952 # comparing and digit/sign extration
2953 $x->bcmp($y); # compare numbers (undef,<0,=0,>0)
2954 $x->bacmp($y); # compare absolutely (undef,<0,=0,>0)
2955 $x->sign(); # return the sign, either +,- or NaN
2956 $x->digit($n); # return the nth digit, counting from right
2957 $x->digit(-$n); # return the nth digit, counting from left
2959 # The following all modify their first argument. If you want to preserve
2960 # $x, use $z = $x->copy()->bXXX($y); See under L<CAVEATS> for why this is
2961 # neccessary when mixing $a = $b assigments with non-overloaded math.
2963 $x->bzero(); # set $x to 0
2964 $x->bnan(); # set $x to NaN
2965 $x->bone(); # set $x to +1
2966 $x->bone('-'); # set $x to -1
2967 $x->binf(); # set $x to inf
2968 $x->binf('-'); # set $x to -inf
2970 $x->bneg(); # negation
2971 $x->babs(); # absolute value
2972 $x->bnorm(); # normalize (no-op in BigInt)
2973 $x->bnot(); # two's complement (bit wise not)
2974 $x->binc(); # increment $x by 1
2975 $x->bdec(); # decrement $x by 1
2977 $x->badd($y); # addition (add $y to $x)
2978 $x->bsub($y); # subtraction (subtract $y from $x)
2979 $x->bmul($y); # multiplication (multiply $x by $y)
2980 $x->bdiv($y); # divide, set $x to quotient
2981 # return (quo,rem) or quo if scalar
2983 $x->bmod($y); # modulus (x % y)
2984 $x->bmodpow($exp,$mod); # modular exponentation (($num**$exp) % $mod))
2985 $x->bmodinv($mod); # the inverse of $x in the given modulus $mod
2987 $x->bpow($y); # power of arguments (x ** y)
2988 $x->blsft($y); # left shift
2989 $x->brsft($y); # right shift
2990 $x->blsft($y,$n); # left shift, by base $n (like 10)
2991 $x->brsft($y,$n); # right shift, by base $n (like 10)
2993 $x->band($y); # bitwise and
2994 $x->bior($y); # bitwise inclusive or
2995 $x->bxor($y); # bitwise exclusive or
2996 $x->bnot(); # bitwise not (two's complement)
2998 $x->bsqrt(); # calculate square-root
2999 $x->broot($y); # $y'th root of $x (e.g. $y == 3 => cubic root)
3000 $x->bfac(); # factorial of $x (1*2*3*4*..$x)
3002 $x->round($A,$P,$mode); # round to accuracy or precision using mode $mode
3003 $x->bround($N); # accuracy: preserve $N digits
3004 $x->bfround($N); # round to $Nth digit, no-op for BigInts
3006 # The following do not modify their arguments in BigInt (are no-ops),
3007 # but do so in BigFloat:
3009 $x->bfloor(); # return integer less or equal than $x
3010 $x->bceil(); # return integer greater or equal than $x
3012 # The following do not modify their arguments:
3014 bgcd(@values); # greatest common divisor (no OO style)
3015 blcm(@values); # lowest common multiplicator (no OO style)
3017 $x->length(); # return number of digits in number
3018 ($x,$f) = $x->length(); # length of number and length of fraction part,
3019 # latter is always 0 digits long for BigInt's
3021 $x->exponent(); # return exponent as BigInt
3022 $x->mantissa(); # return (signed) mantissa as BigInt
3023 $x->parts(); # return (mantissa,exponent) as BigInt
3024 $x->copy(); # make a true copy of $x (unlike $y = $x;)
3025 $x->as_number(); # return as BigInt (in BigInt: same as copy())
3027 # conversation to string (do not modify their argument)
3028 $x->bstr(); # normalized string
3029 $x->bsstr(); # normalized string in scientific notation
3030 $x->as_hex(); # as signed hexadecimal string with prefixed 0x
3031 $x->as_bin(); # as signed binary string with prefixed 0b
3034 # precision and accuracy (see section about rounding for more)
3035 $x->precision(); # return P of $x (or global, if P of $x undef)
3036 $x->precision($n); # set P of $x to $n
3037 $x->accuracy(); # return A of $x (or global, if A of $x undef)
3038 $x->accuracy($n); # set A $x to $n
3041 Math::BigInt->precision(); # get/set global P for all BigInt objects
3042 Math::BigInt->accuracy(); # get/set global A for all BigInt objects
3043 Math::BigInt->config(); # return hash containing configuration
3047 All operators (inlcuding basic math operations) are overloaded if you
3048 declare your big integers as
3050 $i = new Math::BigInt '123_456_789_123_456_789';
3052 Operations with overloaded operators preserve the arguments which is
3053 exactly what you expect.
3059 Input values to these routines may be any string, that looks like a number
3060 and results in an integer, including hexadecimal and binary numbers.
3062 Scalars holding numbers may also be passed, but note that non-integer numbers
3063 may already have lost precision due to the conversation to float. Quote
3064 your input if you want BigInt to see all the digits.
3066 $x = Math::BigInt->new(12345678890123456789); # bad
3067 $x = Math::BigInt->new('12345678901234567890'); # good
3069 You can include one underscore between any two digits.
3071 This means integer values like 1.01E2 or even 1000E-2 are also accepted.
3072 Non-integer values result in NaN.
3074 Currently, Math::BigInt::new() defaults to 0, while Math::BigInt::new('')
3077 C<bnorm()> on a BigInt object is now effectively a no-op, since the numbers
3078 are always stored in normalized form. On a string, it creates a BigInt
3079 object from the input.
3083 Output values are BigInt objects (normalized), except for bstr(), which
3084 returns a string in normalized form.
3085 Some routines (C<is_odd()>, C<is_even()>, C<is_zero()>, C<is_one()>,
3086 C<is_nan()>) return true or false, while others (C<bcmp()>, C<bacmp()>)
3087 return either undef, <0, 0 or >0 and are suited for sort.
3093 Each of the methods below (except config(), accuracy() and precision())
3094 accepts three additional parameters. These arguments $A, $P and $R are
3095 accuracy, precision and round_mode. Please see the section about
3096 L<ACCURACY and PRECISION> for more information.
3102 print Dumper ( Math::BigInt->config() );
3103 print Math::BigInt->config()->{lib},"\n";
3105 Returns a hash containing the configuration, e.g. the version number, lib
3106 loaded etc. The following hash keys are currently filled in with the
3107 appropriate information.
3111 ============================================================
3112 lib Name of the Math library
3114 lib_version Version of 'lib'
3116 class The class of config you just called
3118 upgrade To which class numbers are upgraded
3120 downgrade To which class numbers are downgraded
3122 precision Global precision
3124 accuracy Global accuracy
3126 round_mode Global round mode
3128 version version number of the class you used
3130 div_scale Fallback acccuracy for div
3133 The following values can be set by passing C<config()> a reference to a hash:
3136 upgrade downgrade precision accuracy round_mode div_scale
3140 $new_cfg = Math::BigInt->config( { trap_inf => 1, precision => 5 } );
3144 $x->accuracy(5); # local for $x
3145 CLASS->accuracy(5); # global for all members of CLASS
3146 $A = $x->accuracy(); # read out
3147 $A = CLASS->accuracy(); # read out
3149 Set or get the global or local accuracy, aka how many significant digits the
3152 Please see the section about L<ACCURACY AND PRECISION> for further details.
3154 Value must be greater than zero. Pass an undef value to disable it:
3156 $x->accuracy(undef);
3157 Math::BigInt->accuracy(undef);
3159 Returns the current accuracy. For C<$x->accuracy()> it will return either the
3160 local accuracy, or if not defined, the global. This means the return value
3161 represents the accuracy that will be in effect for $x:
3163 $y = Math::BigInt->new(1234567); # unrounded
3164 print Math::BigInt->accuracy(4),"\n"; # set 4, print 4
3165 $x = Math::BigInt->new(123456); # will be automatically rounded
3166 print "$x $y\n"; # '123500 1234567'
3167 print $x->accuracy(),"\n"; # will be 4
3168 print $y->accuracy(),"\n"; # also 4, since global is 4
3169 print Math::BigInt->accuracy(5),"\n"; # set to 5, print 5
3170 print $x->accuracy(),"\n"; # still 4
3171 print $y->accuracy(),"\n"; # 5, since global is 5
3173 Note: Works also for subclasses like Math::BigFloat. Each class has it's own
3174 globals separated from Math::BigInt, but it is possible to subclass
3175 Math::BigInt and make the globals of the subclass aliases to the ones from
3180 $x->precision(-2); # local for $x, round right of the dot
3181 $x->precision(2); # ditto, but round left of the dot
3182 CLASS->accuracy(5); # global for all members of CLASS
3183 CLASS->precision(-5); # ditto
3184 $P = CLASS->precision(); # read out
3185 $P = $x->precision(); # read out
3187 Set or get the global or local precision, aka how many digits the result has
3188 after the dot (or where to round it when passing a positive number). In
3189 Math::BigInt, passing a negative number precision has no effect since no
3190 numbers have digits after the dot.
3192 Please see the section about L<ACCURACY AND PRECISION> for further details.
3194 Value must be greater than zero. Pass an undef value to disable it:
3196 $x->precision(undef);
3197 Math::BigInt->precision(undef);
3199 Returns the current precision. For C<$x->precision()> it will return either the
3200 local precision of $x, or if not defined, the global. This means the return
3201 value represents the accuracy that will be in effect for $x:
3203 $y = Math::BigInt->new(1234567); # unrounded
3204 print Math::BigInt->precision(4),"\n"; # set 4, print 4
3205 $x = Math::BigInt->new(123456); # will be automatically rounded
3207 Note: Works also for subclasses like Math::BigFloat. Each class has it's own
3208 globals separated from Math::BigInt, but it is possible to subclass
3209 Math::BigInt and make the globals of the subclass aliases to the ones from
3216 Shifts $x right by $y in base $n. Default is base 2, used are usually 10 and
3217 2, but others work, too.
3219 Right shifting usually amounts to dividing $x by $n ** $y and truncating the
3223 $x = Math::BigInt->new(10);
3224 $x->brsft(1); # same as $x >> 1: 5
3225 $x = Math::BigInt->new(1234);
3226 $x->brsft(2,10); # result 12
3228 There is one exception, and that is base 2 with negative $x:
3231 $x = Math::BigInt->new(-5);
3234 This will print -3, not -2 (as it would if you divide -5 by 2 and truncate the
3239 $x = Math::BigInt->new($str,$A,$P,$R);
3241 Creates a new BigInt object from a scalar or another BigInt object. The
3242 input is accepted as decimal, hex (with leading '0x') or binary (with leading
3245 See L<Input> for more info on accepted input formats.
3249 $x = Math::BigInt->bnan();
3251 Creates a new BigInt object representing NaN (Not A Number).
3252 If used on an object, it will set it to NaN:
3258 $x = Math::BigInt->bzero();
3260 Creates a new BigInt object representing zero.
3261 If used on an object, it will set it to zero:
3267 $x = Math::BigInt->binf($sign);
3269 Creates a new BigInt object representing infinity. The optional argument is
3270 either '-' or '+', indicating whether you want infinity or minus infinity.
3271 If used on an object, it will set it to infinity:
3278 $x = Math::BigInt->binf($sign);
3280 Creates a new BigInt object representing one. The optional argument is
3281 either '-' or '+', indicating whether you want one or minus one.
3282 If used on an object, it will set it to one:
3287 =head2 is_one()/is_zero()/is_nan()/is_inf()
3290 $x->is_zero(); # true if arg is +0
3291 $x->is_nan(); # true if arg is NaN
3292 $x->is_one(); # true if arg is +1
3293 $x->is_one('-'); # true if arg is -1
3294 $x->is_inf(); # true if +inf
3295 $x->is_inf('-'); # true if -inf (sign is default '+')
3297 These methods all test the BigInt for beeing one specific value and return
3298 true or false depending on the input. These are faster than doing something
3303 =head2 is_positive()/is_negative()
3305 $x->is_positive(); # true if >= 0
3306 $x->is_negative(); # true if < 0
3308 The methods return true if the argument is positive or negative, respectively.
3309 C<NaN> is neither positive nor negative, while C<+inf> counts as positive, and
3310 C<-inf> is negative. A C<zero> is positive.
3312 These methods are only testing the sign, and not the value.
3314 =head2 is_odd()/is_even()/is_int()
3316 $x->is_odd(); # true if odd, false for even
3317 $x->is_even(); # true if even, false for odd
3318 $x->is_int(); # true if $x is an integer
3320 The return true when the argument satisfies the condition. C<NaN>, C<+inf>,
3321 C<-inf> are not integers and are neither odd nor even.
3323 In BigInt, all numbers except C<NaN>, C<+inf> and C<-inf> are integers.
3329 Compares $x with $y and takes the sign into account.
3330 Returns -1, 0, 1 or undef.
3336 Compares $x with $y while ignoring their. Returns -1, 0, 1 or undef.
3342 Return the sign, of $x, meaning either C<+>, C<->, C<-inf>, C<+inf> or NaN.
3346 $x->digit($n); # return the nth digit, counting from right
3352 Negate the number, e.g. change the sign between '+' and '-', or between '+inf'
3353 and '-inf', respectively. Does nothing for NaN or zero.
3359 Set the number to it's absolute value, e.g. change the sign from '-' to '+'
3360 and from '-inf' to '+inf', respectively. Does nothing for NaN or positive
3365 $x->bnorm(); # normalize (no-op)
3369 $x->bnot(); # two's complement (bit wise not)
3373 $x->binc(); # increment x by 1
3377 $x->bdec(); # decrement x by 1
3381 $x->badd($y); # addition (add $y to $x)
3385 $x->bsub($y); # subtraction (subtract $y from $x)
3389 $x->bmul($y); # multiplication (multiply $x by $y)
3393 $x->bdiv($y); # divide, set $x to quotient
3394 # return (quo,rem) or quo if scalar
3398 $x->bmod($y); # modulus (x % y)
3402 num->bmodinv($mod); # modular inverse
3404 Returns the inverse of C<$num> in the given modulus C<$mod>. 'C<NaN>' is
3405 returned unless C<$num> is relatively prime to C<$mod>, i.e. unless
3406 C<bgcd($num, $mod)==1>.
3410 $num->bmodpow($exp,$mod); # modular exponentation
3411 # ($num**$exp % $mod)
3413 Returns the value of C<$num> taken to the power C<$exp> in the modulus
3414 C<$mod> using binary exponentation. C<bmodpow> is far superior to
3419 because C<bmodpow> is much faster--it reduces internal variables into
3420 the modulus whenever possible, so it operates on smaller numbers.
3422 C<bmodpow> also supports negative exponents.
3424 bmodpow($num, -1, $mod)
3426 is exactly equivalent to
3432 $x->bpow($y); # power of arguments (x ** y)
3436 $x->blsft($y); # left shift
3437 $x->blsft($y,$n); # left shift, in base $n (like 10)
3441 $x->brsft($y); # right shift
3442 $x->brsft($y,$n); # right shift, in base $n (like 10)
3446 $x->band($y); # bitwise and
3450 $x->bior($y); # bitwise inclusive or
3454 $x->bxor($y); # bitwise exclusive or
3458 $x->bnot(); # bitwise not (two's complement)
3462 $x->bsqrt(); # calculate square-root
3466 $x->bfac(); # factorial of $x (1*2*3*4*..$x)
3470 $x->round($A,$P,$round_mode);
3472 Round $x to accuracy C<$A> or precision C<$P> using the round mode
3477 $x->bround($N); # accuracy: preserve $N digits
3481 $x->bfround($N); # round to $Nth digit, no-op for BigInts
3487 Set $x to the integer less or equal than $x. This is a no-op in BigInt, but
3488 does change $x in BigFloat.
3494 Set $x to the integer greater or equal than $x. This is a no-op in BigInt, but
3495 does change $x in BigFloat.
3499 bgcd(@values); # greatest common divisor (no OO style)
3503 blcm(@values); # lowest common multiplicator (no OO style)
3508 ($xl,$fl) = $x->length();
3510 Returns the number of digits in the decimal representation of the number.
3511 In list context, returns the length of the integer and fraction part. For
3512 BigInt's, the length of the fraction part will always be 0.
3518 Return the exponent of $x as BigInt.
3524 Return the signed mantissa of $x as BigInt.
3528 $x->parts(); # return (mantissa,exponent) as BigInt
3532 $x->copy(); # make a true copy of $x (unlike $y = $x;)
3536 $x->as_number(); # return as BigInt (in BigInt: same as copy())
3540 $x->bstr(); # return normalized string
3544 $x->bsstr(); # normalized string in scientific notation
3548 $x->as_hex(); # as signed hexadecimal string with prefixed 0x
3552 $x->as_bin(); # as signed binary string with prefixed 0b
3554 =head1 ACCURACY and PRECISION
3556 Since version v1.33, Math::BigInt and Math::BigFloat have full support for
3557 accuracy and precision based rounding, both automatically after every
3558 operation as well as manually.
3560 This section describes the accuracy/precision handling in Math::Big* as it
3561 used to be and as it is now, complete with an explanation of all terms and
3564 Not yet implemented things (but with correct description) are marked with '!',
3565 things that need to be answered are marked with '?'.
3567 In the next paragraph follows a short description of terms used here (because
3568 these may differ from terms used by others people or documentation).
3570 During the rest of this document, the shortcuts A (for accuracy), P (for
3571 precision), F (fallback) and R (rounding mode) will be used.
3575 A fixed number of digits before (positive) or after (negative)
3576 the decimal point. For example, 123.45 has a precision of -2. 0 means an
3577 integer like 123 (or 120). A precision of 2 means two digits to the left
3578 of the decimal point are zero, so 123 with P = 1 becomes 120. Note that
3579 numbers with zeros before the decimal point may have different precisions,
3580 because 1200 can have p = 0, 1 or 2 (depending on what the inital value
3581 was). It could also have p < 0, when the digits after the decimal point
3584 The string output (of floating point numbers) will be padded with zeros:
3586 Initial value P A Result String
3587 ------------------------------------------------------------
3588 1234.01 -3 1000 1000
3591 1234.001 1 1234 1234.0
3593 1234.01 2 1234.01 1234.01
3594 1234.01 5 1234.01 1234.01000
3596 For BigInts, no padding occurs.
3600 Number of significant digits. Leading zeros are not counted. A
3601 number may have an accuracy greater than the non-zero digits
3602 when there are zeros in it or trailing zeros. For example, 123.456 has
3603 A of 6, 10203 has 5, 123.0506 has 7, 123.450000 has 8 and 0.000123 has 3.
3605 The string output (of floating point numbers) will be padded with zeros:
3607 Initial value P A Result String
3608 ------------------------------------------------------------
3610 1234.01 6 1234.01 1234.01
3611 1234.1 8 1234.1 1234.1000
3613 For BigInts, no padding occurs.
3617 When both A and P are undefined, this is used as a fallback accuracy when
3620 =head2 Rounding mode R
3622 When rounding a number, different 'styles' or 'kinds'
3623 of rounding are possible. (Note that random rounding, as in
3624 Math::Round, is not implemented.)
3630 truncation invariably removes all digits following the
3631 rounding place, replacing them with zeros. Thus, 987.65 rounded
3632 to tens (P=1) becomes 980, and rounded to the fourth sigdig
3633 becomes 987.6 (A=4). 123.456 rounded to the second place after the
3634 decimal point (P=-2) becomes 123.46.
3636 All other implemented styles of rounding attempt to round to the
3637 "nearest digit." If the digit D immediately to the right of the
3638 rounding place (skipping the decimal point) is greater than 5, the
3639 number is incremented at the rounding place (possibly causing a
3640 cascade of incrementation): e.g. when rounding to units, 0.9 rounds
3641 to 1, and -19.9 rounds to -20. If D < 5, the number is similarly
3642 truncated at the rounding place: e.g. when rounding to units, 0.4
3643 rounds to 0, and -19.4 rounds to -19.
3645 However the results of other styles of rounding differ if the
3646 digit immediately to the right of the rounding place (skipping the
3647 decimal point) is 5 and if there are no digits, or no digits other
3648 than 0, after that 5. In such cases:
3652 rounds the digit at the rounding place to 0, 2, 4, 6, or 8
3653 if it is not already. E.g., when rounding to the first sigdig, 0.45
3654 becomes 0.4, -0.55 becomes -0.6, but 0.4501 becomes 0.5.
3658 rounds the digit at the rounding place to 1, 3, 5, 7, or 9 if
3659 it is not already. E.g., when rounding to the first sigdig, 0.45
3660 becomes 0.5, -0.55 becomes -0.5, but 0.5501 becomes 0.6.
3664 round to plus infinity, i.e. always round up. E.g., when
3665 rounding to the first sigdig, 0.45 becomes 0.5, -0.55 becomes -0.5,
3666 and 0.4501 also becomes 0.5.
3670 round to minus infinity, i.e. always round down. E.g., when
3671 rounding to the first sigdig, 0.45 becomes 0.4, -0.55 becomes -0.6,
3672 but 0.4501 becomes 0.5.
3676 round to zero, i.e. positive numbers down, negative ones up.
3677 E.g., when rounding to the first sigdig, 0.45 becomes 0.4, -0.55
3678 becomes -0.5, but 0.4501 becomes 0.5.
3682 The handling of A & P in MBI/MBF (the old core code shipped with Perl
3683 versions <= 5.7.2) is like this:
3689 * ffround($p) is able to round to $p number of digits after the decimal
3691 * otherwise P is unused
3693 =item Accuracy (significant digits)
3695 * fround($a) rounds to $a significant digits
3696 * only fdiv() and fsqrt() take A as (optional) paramater
3697 + other operations simply create the same number (fneg etc), or more (fmul)
3699 + rounding/truncating is only done when explicitly calling one of fround
3700 or ffround, and never for BigInt (not implemented)
3701 * fsqrt() simply hands its accuracy argument over to fdiv.
3702 * the documentation and the comment in the code indicate two different ways
3703 on how fdiv() determines the maximum number of digits it should calculate,
3704 and the actual code does yet another thing
3706 max($Math::BigFloat::div_scale,length(dividend)+length(divisor))
3708 result has at most max(scale, length(dividend), length(divisor)) digits
3710 scale = max(scale, length(dividend)-1,length(divisor)-1);
3711 scale += length(divisior) - length(dividend);
3712 So for lx = 3, ly = 9, scale = 10, scale will actually be 16 (10+9-3).
3713 Actually, the 'difference' added to the scale is calculated from the
3714 number of "significant digits" in dividend and divisor, which is derived
3715 by looking at the length of the mantissa. Which is wrong, since it includes
3716 the + sign (oups) and actually gets 2 for '+100' and 4 for '+101'. Oups
3717 again. Thus 124/3 with div_scale=1 will get you '41.3' based on the strange
3718 assumption that 124 has 3 significant digits, while 120/7 will get you
3719 '17', not '17.1' since 120 is thought to have 2 significant digits.
3720 The rounding after the division then uses the remainder and $y to determine
3721 wether it must round up or down.
3722 ? I have no idea which is the right way. That's why I used a slightly more
3723 ? simple scheme and tweaked the few failing testcases to match it.
3727 This is how it works now:
3731 =item Setting/Accessing
3733 * You can set the A global via Math::BigInt->accuracy() or
3734 Math::BigFloat->accuracy() or whatever class you are using.
3735 * You can also set P globally by using Math::SomeClass->precision() likewise.
3736 * Globals are classwide, and not inherited by subclasses.
3737 * to undefine A, use Math::SomeCLass->accuracy(undef);
3738 * to undefine P, use Math::SomeClass->precision(undef);
3739 * Setting Math::SomeClass->accuracy() clears automatically
3740 Math::SomeClass->precision(), and vice versa.
3741 * To be valid, A must be > 0, P can have any value.
3742 * If P is negative, this means round to the P'th place to the right of the
3743 decimal point; positive values mean to the left of the decimal point.
3744 P of 0 means round to integer.
3745 * to find out the current global A, take Math::SomeClass->accuracy()
3746 * to find out the current global P, take Math::SomeClass->precision()
3747 * use $x->accuracy() respective $x->precision() for the local setting of $x.
3748 * Please note that $x->accuracy() respecive $x->precision() fall back to the
3749 defined globals, when $x's A or P is not set.
3751 =item Creating numbers
3753 * When you create a number, you can give it's desired A or P via:
3754 $x = Math::BigInt->new($number,$A,$P);
3755 * Only one of A or P can be defined, otherwise the result is NaN
3756 * If no A or P is give ($x = Math::BigInt->new($number) form), then the
3757 globals (if set) will be used. Thus changing the global defaults later on
3758 will not change the A or P of previously created numbers (i.e., A and P of
3759 $x will be what was in effect when $x was created)
3760 * If given undef for A and P, B<no> rounding will occur, and the globals will
3761 B<not> be used. This is used by subclasses to create numbers without
3762 suffering rounding in the parent. Thus a subclass is able to have it's own
3763 globals enforced upon creation of a number by using
3764 $x = Math::BigInt->new($number,undef,undef):
3766 use Math::BigInt::SomeSubclass;
3769 Math::BigInt->accuracy(2);
3770 Math::BigInt::SomeSubClass->accuracy(3);
3771 $x = Math::BigInt::SomeSubClass->new(1234);
3773 $x is now 1230, and not 1200. A subclass might choose to implement
3774 this otherwise, e.g. falling back to the parent's A and P.
3778 * If A or P are enabled/defined, they are used to round the result of each
3779 operation according to the rules below
3780 * Negative P is ignored in Math::BigInt, since BigInts never have digits
3781 after the decimal point
3782 * Math::BigFloat uses Math::BigInts internally, but setting A or P inside
3783 Math::BigInt as globals should not tamper with the parts of a BigFloat.
3784 Thus a flag is used to mark all Math::BigFloat numbers as 'never round'
3788 * It only makes sense that a number has only one of A or P at a time.
3789 Since you can set/get both A and P, there is a rule that will practically
3790 enforce only A or P to be in effect at a time, even if both are set.
3791 This is called precedence.
3792 * If two objects are involved in an operation, and one of them has A in
3793 effect, and the other P, this results in an error (NaN).
3794 * A takes precendence over P (Hint: A comes before P). If A is defined, it
3795 is used, otherwise P is used. If neither of them is defined, nothing is
3796 used, i.e. the result will have as many digits as it can (with an
3797 exception for fdiv/fsqrt) and will not be rounded.
3798 * There is another setting for fdiv() (and thus for fsqrt()). If neither of
3799 A or P is defined, fdiv() will use a fallback (F) of $div_scale digits.
3800 If either the dividend's or the divisor's mantissa has more digits than
3801 the value of F, the higher value will be used instead of F.
3802 This is to limit the digits (A) of the result (just consider what would
3803 happen with unlimited A and P in the case of 1/3 :-)
3804 * fdiv will calculate (at least) 4 more digits than required (determined by
3805 A, P or F), and, if F is not used, round the result
3806 (this will still fail in the case of a result like 0.12345000000001 with A
3807 or P of 5, but this can not be helped - or can it?)
3808 * Thus you can have the math done by on Math::Big* class in three modes:
3809 + never round (this is the default):
3810 This is done by setting A and P to undef. No math operation
3811 will round the result, with fdiv() and fsqrt() as exceptions to guard
3812 against overflows. You must explicitely call bround(), bfround() or
3813 round() (the latter with parameters).
3814 Note: Once you have rounded a number, the settings will 'stick' on it
3815 and 'infect' all other numbers engaged in math operations with it, since
3816 local settings have the highest precedence. So, to get SaferRound[tm],
3817 use a copy() before rounding like this:
3819 $x = Math::BigFloat->new(12.34);
3820 $y = Math::BigFloat->new(98.76);
3821 $z = $x * $y; # 1218.6984
3822 print $x->copy()->fround(3); # 12.3 (but A is now 3!)
3823 $z = $x * $y; # still 1218.6984, without
3824 # copy would have been 1210!
3826 + round after each op:
3827 After each single operation (except for testing like is_zero()), the
3828 method round() is called and the result is rounded appropriately. By
3829 setting proper values for A and P, you can have all-the-same-A or
3830 all-the-same-P modes. For example, Math::Currency might set A to undef,
3831 and P to -2, globally.
3833 ?Maybe an extra option that forbids local A & P settings would be in order,
3834 ?so that intermediate rounding does not 'poison' further math?
3836 =item Overriding globals
3838 * you will be able to give A, P and R as an argument to all the calculation
3839 routines; the second parameter is A, the third one is P, and the fourth is
3840 R (shift right by one for binary operations like badd). P is used only if
3841 the first parameter (A) is undefined. These three parameters override the
3842 globals in the order detailed as follows, i.e. the first defined value
3844 (local: per object, global: global default, parameter: argument to sub)
3847 + local A (if defined on both of the operands: smaller one is taken)
3848 + local P (if defined on both of the operands: bigger one is taken)
3852 * fsqrt() will hand its arguments to fdiv(), as it used to, only now for two
3853 arguments (A and P) instead of one
3855 =item Local settings
3857 * You can set A and P locally by using $x->accuracy() and $x->precision()
3858 and thus force different A and P for different objects/numbers.
3859 * Setting A or P this way immediately rounds $x to the new value.
3860 * $x->accuracy() clears $x->precision(), and vice versa.
3864 * the rounding routines will use the respective global or local settings.
3865 fround()/bround() is for accuracy rounding, while ffround()/bfround()
3867 * the two rounding functions take as the second parameter one of the
3868 following rounding modes (R):
3869 'even', 'odd', '+inf', '-inf', 'zero', 'trunc'
3870 * you can set and get the global R by using Math::SomeClass->round_mode()
3871 or by setting $Math::SomeClass::round_mode
3872 * after each operation, $result->round() is called, and the result may
3873 eventually be rounded (that is, if A or P were set either locally,
3874 globally or as parameter to the operation)
3875 * to manually round a number, call $x->round($A,$P,$round_mode);
3876 this will round the number by using the appropriate rounding function
3877 and then normalize it.
3878 * rounding modifies the local settings of the number:
3880 $x = Math::BigFloat->new(123.456);
3884 Here 4 takes precedence over 5, so 123.5 is the result and $x->accuracy()
3885 will be 4 from now on.
3887 =item Default values
3896 * The defaults are set up so that the new code gives the same results as
3897 the old code (except in a few cases on fdiv):
3898 + Both A and P are undefined and thus will not be used for rounding
3899 after each operation.
3900 + round() is thus a no-op, unless given extra parameters A and P
3906 The actual numbers are stored as unsigned big integers (with seperate sign).
3907 You should neither care about nor depend on the internal representation; it
3908 might change without notice. Use only method calls like C<< $x->sign(); >>
3909 instead relying on the internal hash keys like in C<< $x->{sign}; >>.
3913 Math with the numbers is done (by default) by a module called
3914 Math::BigInt::Calc. This is equivalent to saying:
3916 use Math::BigInt lib => 'Calc';
3918 You can change this by using:
3920 use Math::BigInt lib => 'BitVect';
3922 The following would first try to find Math::BigInt::Foo, then
3923 Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
3925 use Math::BigInt lib => 'Foo,Math::BigInt::Bar';
3927 Calc.pm uses as internal format an array of elements of some decimal base
3928 (usually 1e5 or 1e7) with the least significant digit first, while BitVect.pm
3929 uses a bit vector of base 2, most significant bit first. Other modules might
3930 use even different means of representing the numbers. See the respective
3931 module documentation for further details.
3935 The sign is either '+', '-', 'NaN', '+inf' or '-inf' and stored seperately.
3937 A sign of 'NaN' is used to represent the result when input arguments are not
3938 numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively
3939 minus infinity. You will get '+inf' when dividing a positive number by 0, and
3940 '-inf' when dividing any negative number by 0.
3942 =head2 mantissa(), exponent() and parts()
3944 C<mantissa()> and C<exponent()> return the said parts of the BigInt such
3947 $m = $x->mantissa();
3948 $e = $x->exponent();
3949 $y = $m * ( 10 ** $e );
3950 print "ok\n" if $x == $y;
3952 C<< ($m,$e) = $x->parts() >> is just a shortcut that gives you both of them
3953 in one go. Both the returned mantissa and exponent have a sign.
3955 Currently, for BigInts C<$e> will be always 0, except for NaN, +inf and -inf,
3956 where it will be NaN; and for $x == 0, where it will be 1
3957 (to be compatible with Math::BigFloat's internal representation of a zero as
3960 C<$m> will always be a copy of the original number. The relation between $e
3961 and $m might change in the future, but will always be equivalent in a
3962 numerical sense, e.g. $m might get minimized.
3968 sub bint { Math::BigInt->new(shift); }
3970 $x = Math::BigInt->bstr("1234") # string "1234"
3971 $x = "$x"; # same as bstr()
3972 $x = Math::BigInt->bneg("1234"); # BigInt "-1234"
3973 $x = Math::BigInt->babs("-12345"); # BigInt "12345"
3974 $x = Math::BigInt->bnorm("-0 00"); # BigInt "0"
3975 $x = bint(1) + bint(2); # BigInt "3"
3976 $x = bint(1) + "2"; # ditto (auto-BigIntify of "2")
3977 $x = bint(1); # BigInt "1"
3978 $x = $x + 5 / 2; # BigInt "3"
3979 $x = $x ** 3; # BigInt "27"
3980 $x *= 2; # BigInt "54"
3981 $x = Math::BigInt->new(0); # BigInt "0"
3983 $x = Math::BigInt->badd(4,5) # BigInt "9"
3984 print $x->bsstr(); # 9e+0
3986 Examples for rounding:
3991 $x = Math::BigFloat->new(123.4567);
3992 $y = Math::BigFloat->new(123.456789);
3993 Math::BigFloat->accuracy(4); # no more A than 4
3995 ok ($x->copy()->fround(),123.4); # even rounding
3996 print $x->copy()->fround(),"\n"; # 123.4
3997 Math::BigFloat->round_mode('odd'); # round to odd
3998 print $x->copy()->fround(),"\n"; # 123.5
3999 Math::BigFloat->accuracy(5); # no more A than 5
4000 Math::BigFloat->round_mode('odd'); # round to odd
4001 print $x->copy()->fround(),"\n"; # 123.46
4002 $y = $x->copy()->fround(4),"\n"; # A = 4: 123.4
4003 print "$y, ",$y->accuracy(),"\n"; # 123.4, 4
4005 Math::BigFloat->accuracy(undef); # A not important now
4006 Math::BigFloat->precision(2); # P important
4007 print $x->copy()->bnorm(),"\n"; # 123.46
4008 print $x->copy()->fround(),"\n"; # 123.46
4010 Examples for converting:
4012 my $x = Math::BigInt->new('0b1'.'01' x 123);
4013 print "bin: ",$x->as_bin()," hex:",$x->as_hex()," dec: ",$x,"\n";
4015 =head1 Autocreating constants
4017 After C<use Math::BigInt ':constant'> all the B<integer> decimal, hexadecimal
4018 and binary constants in the given scope are converted to C<Math::BigInt>.
4019 This conversion happens at compile time.
4023 perl -MMath::BigInt=:constant -e 'print 2**100,"\n"'
4025 prints the integer value of C<2**100>. Note that without conversion of
4026 constants the expression 2**100 will be calculated as perl scalar.
4028 Please note that strings and floating point constants are not affected,
4031 use Math::BigInt qw/:constant/;
4033 $x = 1234567890123456789012345678901234567890
4034 + 123456789123456789;
4035 $y = '1234567890123456789012345678901234567890'
4036 + '123456789123456789';
4038 do not work. You need an explicit Math::BigInt->new() around one of the
4039 operands. You should also quote large constants to protect loss of precision:
4043 $x = Math::BigInt->new('1234567889123456789123456789123456789');
4045 Without the quotes Perl would convert the large number to a floating point
4046 constant at compile time and then hand the result to BigInt, which results in
4047 an truncated result or a NaN.
4049 This also applies to integers that look like floating point constants:
4051 use Math::BigInt ':constant';
4053 print ref(123e2),"\n";
4054 print ref(123.2e2),"\n";
4056 will print nothing but newlines. Use either L<bignum> or L<Math::BigFloat>
4057 to get this to work.
4061 Using the form $x += $y; etc over $x = $x + $y is faster, since a copy of $x
4062 must be made in the second case. For long numbers, the copy can eat up to 20%
4063 of the work (in the case of addition/subtraction, less for
4064 multiplication/division). If $y is very small compared to $x, the form
4065 $x += $y is MUCH faster than $x = $x + $y since making the copy of $x takes
4066 more time then the actual addition.
4068 With a technique called copy-on-write, the cost of copying with overload could
4069 be minimized or even completely avoided. A test implementation of COW did show
4070 performance gains for overloaded math, but introduced a performance loss due
4071 to a constant overhead for all other operatons.
4073 The rewritten version of this module is slower on certain operations, like
4074 new(), bstr() and numify(). The reason are that it does now more work and
4075 handles more cases. The time spent in these operations is usually gained in
4076 the other operations so that programs on the average should get faster. If
4077 they don't, please contect the author.
4079 Some operations may be slower for small numbers, but are significantly faster
4080 for big numbers. Other operations are now constant (O(1), like bneg(), babs()
4081 etc), instead of O(N) and thus nearly always take much less time. These
4082 optimizations were done on purpose.
4084 If you find the Calc module to slow, try to install any of the replacement
4085 modules and see if they help you.
4087 =head2 Alternative math libraries
4089 You can use an alternative library to drive Math::BigInt via:
4091 use Math::BigInt lib => 'Module';
4093 See L<MATH LIBRARY> for more information.
4095 For more benchmark results see L<http://bloodgate.com/perl/benchmarks.html>.
4099 =head1 Subclassing Math::BigInt
4101 The basic design of Math::BigInt allows simple subclasses with very little
4102 work, as long as a few simple rules are followed:
4108 The public API must remain consistent, i.e. if a sub-class is overloading
4109 addition, the sub-class must use the same name, in this case badd(). The
4110 reason for this is that Math::BigInt is optimized to call the object methods
4115 The private object hash keys like C<$x->{sign}> may not be changed, but
4116 additional keys can be added, like C<$x->{_custom}>.
4120 Accessor functions are available for all existing object hash keys and should
4121 be used instead of directly accessing the internal hash keys. The reason for
4122 this is that Math::BigInt itself has a pluggable interface which permits it
4123 to support different storage methods.
4127 More complex sub-classes may have to replicate more of the logic internal of
4128 Math::BigInt if they need to change more basic behaviors. A subclass that
4129 needs to merely change the output only needs to overload C<bstr()>.
4131 All other object methods and overloaded functions can be directly inherited
4132 from the parent class.
4134 At the very minimum, any subclass will need to provide it's own C<new()> and can
4135 store additional hash keys in the object. There are also some package globals
4136 that must be defined, e.g.:
4140 $precision = -2; # round to 2 decimal places
4141 $round_mode = 'even';
4144 Additionally, you might want to provide the following two globals to allow
4145 auto-upgrading and auto-downgrading to work correctly:
4150 This allows Math::BigInt to correctly retrieve package globals from the
4151 subclass, like C<$SubClass::precision>. See t/Math/BigInt/Subclass.pm or
4152 t/Math/BigFloat/SubClass.pm completely functional subclass examples.
4158 in your subclass to automatically inherit the overloading from the parent. If
4159 you like, you can change part of the overloading, look at Math::String for an
4164 When used like this:
4166 use Math::BigInt upgrade => 'Foo::Bar';
4168 certain operations will 'upgrade' their calculation and thus the result to
4169 the class Foo::Bar. Usually this is used in conjunction with Math::BigFloat:
4171 use Math::BigInt upgrade => 'Math::BigFloat';
4173 As a shortcut, you can use the module C<bignum>:
4177 Also good for oneliners:
4179 perl -Mbignum -le 'print 2 ** 255'
4181 This makes it possible to mix arguments of different classes (as in 2.5 + 2)
4182 as well es preserve accuracy (as in sqrt(3)).
4184 Beware: This feature is not fully implemented yet.
4188 The following methods upgrade themselves unconditionally; that is if upgrade
4189 is in effect, they will always hand up their work:
4201 Beware: This list is not complete.
4203 All other methods upgrade themselves only when one (or all) of their
4204 arguments are of the class mentioned in $upgrade (This might change in later
4205 versions to a more sophisticated scheme):
4211 =item broot() does not work
4213 The broot() function in BigInt may only work for small values. This will be
4214 fixed in a later version.
4216 =item Out of Memory!
4218 Under Perl prior to 5.6.0 having an C<use Math::BigInt ':constant';> and
4219 C<eval()> in your code will crash with "Out of memory". This is probably an
4220 overload/exporter bug. You can workaround by not having C<eval()>
4221 and ':constant' at the same time or upgrade your Perl to a newer version.
4223 =item Fails to load Calc on Perl prior 5.6.0
4225 Since eval(' use ...') can not be used in conjunction with ':constant', BigInt
4226 will fall back to eval { require ... } when loading the math lib on Perls
4227 prior to 5.6.0. This simple replaces '::' with '/' and thus might fail on
4228 filesystems using a different seperator.
4234 Some things might not work as you expect them. Below is documented what is
4235 known to be troublesome:
4239 =item stringify, bstr(), bsstr() and 'cmp'
4241 Both stringify and bstr() now drop the leading '+'. The old code would return
4242 '+3', the new returns '3'. This is to be consistent with Perl and to make
4243 cmp (especially with overloading) to work as you expect. It also solves
4244 problems with Test.pm, it's ok() uses 'eq' internally.
4246 Mark said, when asked about to drop the '+' altogether, or make only cmp work:
4248 I agree (with the first alternative), don't add the '+' on positive
4249 numbers. It's not as important anymore with the new internal
4250 form for numbers. It made doing things like abs and neg easier,
4251 but those have to be done differently now anyway.
4253 So, the following examples will now work all as expected:
4256 BEGIN { plan tests => 1 }
4259 my $x = new Math::BigInt 3*3;
4260 my $y = new Math::BigInt 3*3;
4263 print "$x eq 9" if $x eq $y;
4264 print "$x eq 9" if $x eq '9';
4265 print "$x eq 9" if $x eq 3*3;
4267 Additionally, the following still works:
4269 print "$x == 9" if $x == $y;
4270 print "$x == 9" if $x == 9;
4271 print "$x == 9" if $x == 3*3;
4273 There is now a C<bsstr()> method to get the string in scientific notation aka
4274 C<1e+2> instead of C<100>. Be advised that overloaded 'eq' always uses bstr()
4275 for comparisation, but Perl will represent some numbers as 100 and others
4276 as 1e+308. If in doubt, convert both arguments to Math::BigInt before doing eq:
4279 BEGIN { plan tests => 3 }
4282 $x = Math::BigInt->new('1e56'); $y = 1e56;
4283 ok ($x,$y); # will fail
4284 ok ($x->bsstr(),$y); # okay
4285 $y = Math::BigInt->new($y);
4288 Alternatively, simple use <=> for comparisations, that will get it always
4289 right. There is not yet a way to get a number automatically represented as
4290 a string that matches exactly the way Perl represents it.
4294 C<int()> will return (at least for Perl v5.7.1 and up) another BigInt, not a
4297 $x = Math::BigInt->new(123);
4298 $y = int($x); # BigInt 123
4299 $x = Math::BigFloat->new(123.45);
4300 $y = int($x); # BigInt 123
4302 In all Perl versions you can use C<as_number()> for the same effect:
4304 $x = Math::BigFloat->new(123.45);
4305 $y = $x->as_number(); # BigInt 123
4307 This also works for other subclasses, like Math::String.
4309 It is yet unlcear whether overloaded int() should return a scalar or a BigInt.
4313 The following will probably not do what you expect:
4315 $c = Math::BigInt->new(123);
4316 print $c->length(),"\n"; # prints 30
4318 It prints both the number of digits in the number and in the fraction part
4319 since print calls C<length()> in list context. Use something like:
4321 print scalar $c->length(),"\n"; # prints 3
4325 The following will probably not do what you expect:
4327 print $c->bdiv(10000),"\n";
4329 It prints both quotient and remainder since print calls C<bdiv()> in list
4330 context. Also, C<bdiv()> will modify $c, so be carefull. You probably want
4333 print $c / 10000,"\n";
4334 print scalar $c->bdiv(10000),"\n"; # or if you want to modify $c
4338 The quotient is always the greatest integer less than or equal to the
4339 real-valued quotient of the two operands, and the remainder (when it is
4340 nonzero) always has the same sign as the second operand; so, for
4350 As a consequence, the behavior of the operator % agrees with the
4351 behavior of Perl's built-in % operator (as documented in the perlop
4352 manpage), and the equation
4354 $x == ($x / $y) * $y + ($x % $y)
4356 holds true for any $x and $y, which justifies calling the two return
4357 values of bdiv() the quotient and remainder. The only exception to this rule
4358 are when $y == 0 and $x is negative, then the remainder will also be
4359 negative. See below under "infinity handling" for the reasoning behing this.
4361 Perl's 'use integer;' changes the behaviour of % and / for scalars, but will
4362 not change BigInt's way to do things. This is because under 'use integer' Perl
4363 will do what the underlying C thinks is right and this is different for each
4364 system. If you need BigInt's behaving exactly like Perl's 'use integer', bug
4365 the author to implement it ;)
4367 =item infinity handling
4369 Here are some examples that explain the reasons why certain results occur while
4372 The following table shows the result of the division and the remainder, so that
4373 the equation above holds true. Some "ordinary" cases are strewn in to show more
4374 clearly the reasoning:
4376 A / B = C, R so that C * B + R = A
4377 =========================================================
4378 5 / 8 = 0, 5 0 * 8 + 5 = 5
4379 0 / 8 = 0, 0 0 * 8 + 0 = 0
4380 0 / inf = 0, 0 0 * inf + 0 = 0
4381 0 /-inf = 0, 0 0 * -inf + 0 = 0
4382 5 / inf = 0, 5 0 * inf + 5 = 5
4383 5 /-inf = 0, 5 0 * -inf + 5 = 5
4384 -5/ inf = 0, -5 0 * inf + -5 = -5
4385 -5/-inf = 0, -5 0 * -inf + -5 = -5
4386 inf/ 5 = inf, 0 inf * 5 + 0 = inf
4387 -inf/ 5 = -inf, 0 -inf * 5 + 0 = -inf
4388 inf/ -5 = -inf, 0 -inf * -5 + 0 = inf
4389 -inf/ -5 = inf, 0 inf * -5 + 0 = -inf
4390 5/ 5 = 1, 0 1 * 5 + 0 = 5
4391 -5/ -5 = 1, 0 1 * -5 + 0 = -5
4392 inf/ inf = 1, 0 1 * inf + 0 = inf
4393 -inf/-inf = 1, 0 1 * -inf + 0 = -inf
4394 inf/-inf = -1, 0 -1 * -inf + 0 = inf
4395 -inf/ inf = -1, 0 1 * -inf + 0 = -inf
4396 8/ 0 = inf, 8 inf * 0 + 8 = 8
4397 inf/ 0 = inf, inf inf * 0 + inf = inf
4400 These cases below violate the "remainder has the sign of the second of the two
4401 arguments", since they wouldn't match up otherwise.
4403 A / B = C, R so that C * B + R = A
4404 ========================================================
4405 -inf/ 0 = -inf, -inf -inf * 0 + inf = -inf
4406 -8/ 0 = -inf, -8 -inf * 0 + 8 = -8
4408 =item Modifying and =
4412 $x = Math::BigFloat->new(5);
4415 It will not do what you think, e.g. making a copy of $x. Instead it just makes
4416 a second reference to the B<same> object and stores it in $y. Thus anything
4417 that modifies $x (except overloaded operators) will modify $y, and vice versa.
4418 Or in other words, C<=> is only safe if you modify your BigInts only via
4419 overloaded math. As soon as you use a method call it breaks:
4422 print "$x, $y\n"; # prints '10, 10'
4424 If you want a true copy of $x, use:
4428 You can also chain the calls like this, this will make first a copy and then
4431 $y = $x->copy()->bmul(2);
4433 See also the documentation for overload.pm regarding C<=>.
4437 C<bpow()> (and the rounding functions) now modifies the first argument and
4438 returns it, unlike the old code which left it alone and only returned the
4439 result. This is to be consistent with C<badd()> etc. The first three will
4440 modify $x, the last one won't:
4442 print bpow($x,$i),"\n"; # modify $x
4443 print $x->bpow($i),"\n"; # ditto
4444 print $x **= $i,"\n"; # the same
4445 print $x ** $i,"\n"; # leave $x alone
4447 The form C<$x **= $y> is faster than C<$x = $x ** $y;>, though.
4449 =item Overloading -$x
4459 since overload calls C<sub($x,0,1);> instead of C<neg($x)>. The first variant
4460 needs to preserve $x since it does not know that it later will get overwritten.
4461 This makes a copy of $x and takes O(N), but $x->bneg() is O(1).
4463 With Copy-On-Write, this issue would be gone, but C-o-W is not implemented
4464 since it is slower for all other things.
4466 =item Mixing different object types
4468 In Perl you will get a floating point value if you do one of the following:
4474 With overloaded math, only the first two variants will result in a BigFloat:
4479 $mbf = Math::BigFloat->new(5);
4480 $mbi2 = Math::BigInteger->new(5);
4481 $mbi = Math::BigInteger->new(2);
4483 # what actually gets called:
4484 $float = $mbf + $mbi; # $mbf->badd()
4485 $float = $mbf / $mbi; # $mbf->bdiv()
4486 $integer = $mbi + $mbf; # $mbi->badd()
4487 $integer = $mbi2 / $mbi; # $mbi2->bdiv()
4488 $integer = $mbi2 / $mbf; # $mbi2->bdiv()
4490 This is because math with overloaded operators follows the first (dominating)
4491 operand, and the operation of that is called and returns thus the result. So,
4492 Math::BigInt::bdiv() will always return a Math::BigInt, regardless whether
4493 the result should be a Math::BigFloat or the second operant is one.
4495 To get a Math::BigFloat you either need to call the operation manually,
4496 make sure the operands are already of the proper type or casted to that type
4497 via Math::BigFloat->new():
4499 $float = Math::BigFloat->new($mbi2) / $mbi; # = 2.5
4501 Beware of simple "casting" the entire expression, this would only convert
4502 the already computed result:
4504 $float = Math::BigFloat->new($mbi2 / $mbi); # = 2.0 thus wrong!
4506 Beware also of the order of more complicated expressions like:
4508 $integer = ($mbi2 + $mbi) / $mbf; # int / float => int
4509 $integer = $mbi2 / Math::BigFloat->new($mbi); # ditto
4511 If in doubt, break the expression into simpler terms, or cast all operands
4512 to the desired resulting type.
4514 Scalar values are a bit different, since:
4519 will both result in the proper type due to the way the overloaded math works.
4521 This section also applies to other overloaded math packages, like Math::String.
4523 One solution to you problem might be autoupgrading|upgrading. See the
4524 pragmas L<bignum>, L<bigint> and L<bigrat> for an easy way to do this.
4528 C<bsqrt()> works only good if the result is a big integer, e.g. the square
4529 root of 144 is 12, but from 12 the square root is 3, regardless of rounding
4530 mode. The reason is that the result is always truncated to an integer.
4532 If you want a better approximation of the square root, then use:
4534 $x = Math::BigFloat->new(12);
4535 Math::BigFloat->precision(0);
4536 Math::BigFloat->round_mode('even');
4537 print $x->copy->bsqrt(),"\n"; # 4
4539 Math::BigFloat->precision(2);
4540 print $x->bsqrt(),"\n"; # 3.46
4541 print $x->bsqrt(3),"\n"; # 3.464
4545 For negative numbers in base see also L<brsft|brsft>.
4551 This program is free software; you may redistribute it and/or modify it under
4552 the same terms as Perl itself.
4556 L<Math::BigFloat>, L<Math::BigRat> and L<Math::Big> as well as
4557 L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>.
4559 The pragmas L<bignum>, L<bigint> and L<bigrat> also might be of interest
4560 because they solve the autoupgrading/downgrading issue, at least partly.
4563 L<http://search.cpan.org/search?mode=module&query=Math%3A%3ABigInt> contains
4564 more documentation including a full version history, testcases, empty
4565 subclass files and benchmarks.
4569 Original code by Mark Biggar, overloaded interface by Ilya Zakharevich.
4570 Completely rewritten by Tels http://bloodgate.com in late 2000, 2001, 2002
4571 and still at it in 2003.
4573 Many people contributed in one or more ways to the final beast, see the file
4574 CREDITS for an (uncomplete) list. If you miss your name, please drop me a