4 # "Mike had an infinite amount to do and a negative amount of time in which
5 # to do it." - Before and After
8 # The following hash values are used:
9 # value: unsigned int with actual value (as a Math::BigInt::Calc or similiar)
10 # sign : +,-,NaN,+inf,-inf
13 # _f : flags, used by MBF to flag parts of a float as untouchable
15 # Remember not to take shortcuts ala $xs = $x->{value}; $CALC->foo($xs); since
16 # underlying lib might change the reference!
18 my $class = "Math::BigInt";
23 @ISA = qw( Exporter );
24 @EXPORT_OK = qw( objectify bgcd blcm);
26 # _trap_inf and _trap_nan are internal and should never be accessed from the
28 use vars qw/$round_mode $accuracy $precision $div_scale $rnd_mode
29 $upgrade $downgrade $_trap_nan $_trap_inf/;
32 # Inside overload, the first arg is always an object. If the original code had
33 # it reversed (like $x = 2 * $y), then the third paramater is true.
34 # In some cases (like add, $x = $x + 2 is the same as $x = 2 + $x) this makes
35 # no difference, but in some cases it does.
37 # For overloaded ops with only one argument we simple use $_[0]->copy() to
38 # preserve the argument.
40 # Thus inheritance of overload operators becomes possible and transparent for
41 # our subclasses without the need to repeat the entire overload section there.
44 '=' => sub { $_[0]->copy(); },
46 # some shortcuts for speed (assumes that reversed order of arguments is routed
47 # to normal '+' and we thus can always modify first arg. If this is changed,
48 # this breaks and must be adjusted.)
49 '+=' => sub { $_[0]->badd($_[1]); },
50 '-=' => sub { $_[0]->bsub($_[1]); },
51 '*=' => sub { $_[0]->bmul($_[1]); },
52 '/=' => sub { scalar $_[0]->bdiv($_[1]); },
53 '%=' => sub { $_[0]->bmod($_[1]); },
54 '^=' => sub { $_[0]->bxor($_[1]); },
55 '&=' => sub { $_[0]->band($_[1]); },
56 '|=' => sub { $_[0]->bior($_[1]); },
58 '**=' => sub { $_[0]->bpow($_[1]); },
59 '<<=' => sub { $_[0]->blsft($_[1]); },
60 '>>=' => sub { $_[0]->brsft($_[1]); },
62 # not supported by Perl yet
63 '..' => \&_pointpoint,
65 # we might need '==' and '!=' to get things like "NaN == NaN" right
66 '<=>' => sub { $_[2] ?
67 ref($_[0])->bcmp($_[1],$_[0]) :
68 $_[0]->bcmp($_[1]); },
71 "$_[1]" cmp $_[0]->bstr() :
72 $_[0]->bstr() cmp "$_[1]" },
74 # make cos()/sin()/exp() "work" with BigInt's or subclasses
75 'cos' => sub { cos($_[0]->numify()) },
76 'sin' => sub { sin($_[0]->numify()) },
77 'exp' => sub { exp($_[0]->numify()) },
78 'atan2' => sub { $_[2] ?
79 atan2($_[1],$_[0]->numify()) :
80 atan2($_[0]->numify(),$_[1]) },
82 # are not yet overloadable
83 #'hex' => sub { print "hex"; $_[0]; },
84 #'oct' => sub { print "oct"; $_[0]; },
86 'log' => sub { $_[0]->copy()->blog($_[1]); },
87 'int' => sub { $_[0]->copy(); },
88 'neg' => sub { $_[0]->copy()->bneg(); },
89 'abs' => sub { $_[0]->copy()->babs(); },
90 'sqrt' => sub { $_[0]->copy()->bsqrt(); },
91 '~' => sub { $_[0]->copy()->bnot(); },
93 # for subtract it's a bit tricky to not modify b: b-a => -a+b
94 '-' => sub { my $c = $_[0]->copy; $_[2] ?
95 $c->bneg()->badd( $_[1]) :
97 '+' => sub { $_[0]->copy()->badd($_[1]); },
98 '*' => sub { $_[0]->copy()->bmul($_[1]); },
101 $_[2] ? ref($_[0])->new($_[1])->bdiv($_[0]) : $_[0]->copy->bdiv($_[1]);
104 $_[2] ? ref($_[0])->new($_[1])->bmod($_[0]) : $_[0]->copy->bmod($_[1]);
107 $_[2] ? ref($_[0])->new($_[1])->bpow($_[0]) : $_[0]->copy->bpow($_[1]);
110 $_[2] ? ref($_[0])->new($_[1])->blsft($_[0]) : $_[0]->copy->blsft($_[1]);
113 $_[2] ? ref($_[0])->new($_[1])->brsft($_[0]) : $_[0]->copy->brsft($_[1]);
116 $_[2] ? ref($_[0])->new($_[1])->band($_[0]) : $_[0]->copy->band($_[1]);
119 $_[2] ? ref($_[0])->new($_[1])->bior($_[0]) : $_[0]->copy->bior($_[1]);
122 $_[2] ? ref($_[0])->new($_[1])->bxor($_[0]) : $_[0]->copy->bxor($_[1]);
125 # can modify arg of ++ and --, so avoid a copy() for speed, but don't
126 # use $_[0]->bone(), it would modify $_[0] to be 1!
127 '++' => sub { $_[0]->binc() },
128 '--' => sub { $_[0]->bdec() },
130 # if overloaded, O(1) instead of O(N) and twice as fast for small numbers
132 # this kludge is needed for perl prior 5.6.0 since returning 0 here fails :-/
133 # v5.6.1 dumps on this: return !$_[0]->is_zero() || undef; :-(
135 $t = 1 if !$_[0]->is_zero();
139 # the original qw() does not work with the TIESCALAR below, why?
140 # Order of arguments unsignificant
141 '""' => sub { $_[0]->bstr(); },
142 '0+' => sub { $_[0]->numify(); }
145 ##############################################################################
146 # global constants, flags and accessory
148 # These vars are public, but their direct usage is not recommended, use the
149 # accessor methods instead
151 $round_mode = 'even'; # one of 'even', 'odd', '+inf', '-inf', 'zero' or 'trunc'
156 $upgrade = undef; # default is no upgrade
157 $downgrade = undef; # default is no downgrade
159 # These are internally, and not to be used from the outside at all
161 $_trap_nan = 0; # are NaNs ok? set w/ config()
162 $_trap_inf = 0; # are infs ok? set w/ config()
163 my $nan = 'NaN'; # constants for easier life
165 my $CALC = 'Math::BigInt::Calc'; # module to do the low level math
167 my $IMPORT = 0; # was import() called yet?
168 # used to make require work
169 my %WARN; # warn only once for low-level libs
170 my %CAN; # cache for $CALC->can(...)
171 my %CALLBACKS; # callbacks to notify on lib loads
172 my $EMU_LIB = 'Math/BigInt/CalcEmu.pm'; # emulate low-level math
174 ##############################################################################
175 # the old code had $rnd_mode, so we need to support it, too
178 sub TIESCALAR { my ($class) = @_; bless \$round_mode, $class; }
179 sub FETCH { return $round_mode; }
180 sub STORE { $rnd_mode = $_[0]->round_mode($_[1]); }
184 # tie to enable $rnd_mode to work transparently
185 tie $rnd_mode, 'Math::BigInt';
187 # set up some handy alias names
188 *as_int = \&as_number;
189 *is_pos = \&is_positive;
190 *is_neg = \&is_negative;
193 ##############################################################################
198 # make Class->round_mode() work
200 my $class = ref($self) || $self || __PACKAGE__;
204 if ($m !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
206 require Carp; Carp::croak ("Unknown round mode '$m'");
208 return ${"${class}::round_mode"} = $m;
210 ${"${class}::round_mode"};
216 # make Class->upgrade() work
218 my $class = ref($self) || $self || __PACKAGE__;
219 # need to set new value?
222 return ${"${class}::upgrade"} = $_[0];
224 ${"${class}::upgrade"};
230 # make Class->downgrade() work
232 my $class = ref($self) || $self || __PACKAGE__;
233 # need to set new value?
236 return ${"${class}::downgrade"} = $_[0];
238 ${"${class}::downgrade"};
244 # make Class->div_scale() work
246 my $class = ref($self) || $self || __PACKAGE__;
251 require Carp; Carp::croak ('div_scale must be greater than zero');
253 ${"${class}::div_scale"} = $_[0];
255 ${"${class}::div_scale"};
260 # $x->accuracy($a); ref($x) $a
261 # $x->accuracy(); ref($x)
262 # Class->accuracy(); class
263 # Class->accuracy($a); class $a
266 my $class = ref($x) || $x || __PACKAGE__;
269 # need to set new value?
273 # convert objects to scalars to avoid deep recursion. If object doesn't
274 # have numify(), then hopefully it will have overloading for int() and
275 # boolean test without wandering into a deep recursion path...
276 $a = $a->numify() if ref($a) && $a->can('numify');
280 # also croak on non-numerical
284 Carp::croak ('Argument to accuracy must be greater than zero');
288 require Carp; Carp::croak ('Argument to accuracy must be an integer');
293 # $object->accuracy() or fallback to global
294 $x->bround($a) if $a; # not for undef, 0
295 $x->{_a} = $a; # set/overwrite, even if not rounded
296 delete $x->{_p}; # clear P
297 $a = ${"${class}::accuracy"} unless defined $a; # proper return value
301 ${"${class}::accuracy"} = $a; # set global A
302 ${"${class}::precision"} = undef; # clear global P
304 return $a; # shortcut
308 # $object->accuracy() or fallback to global
309 $a = $x->{_a} if ref($x);
310 # but don't return global undef, when $x's accuracy is 0!
311 $a = ${"${class}::accuracy"} if !defined $a;
317 # $x->precision($p); ref($x) $p
318 # $x->precision(); ref($x)
319 # Class->precision(); class
320 # Class->precision($p); class $p
323 my $class = ref($x) || $x || __PACKAGE__;
329 # convert objects to scalars to avoid deep recursion. If object doesn't
330 # have numify(), then hopefully it will have overloading for int() and
331 # boolean test without wandering into a deep recursion path...
332 $p = $p->numify() if ref($p) && $p->can('numify');
333 if ((defined $p) && (int($p) != $p))
335 require Carp; Carp::croak ('Argument to precision must be an integer');
339 # $object->precision() or fallback to global
340 $x->bfround($p) if $p; # not for undef, 0
341 $x->{_p} = $p; # set/overwrite, even if not rounded
342 delete $x->{_a}; # clear A
343 $p = ${"${class}::precision"} unless defined $p; # proper return value
347 ${"${class}::precision"} = $p; # set global P
348 ${"${class}::accuracy"} = undef; # clear global A
350 return $p; # shortcut
354 # $object->precision() or fallback to global
355 $p = $x->{_p} if ref($x);
356 # but don't return global undef, when $x's precision is 0!
357 $p = ${"${class}::precision"} if !defined $p;
363 # return (or set) configuration data as hash ref
364 my $class = shift || 'Math::BigInt';
369 # try to set given options as arguments from hash
372 if (ref($args) ne 'HASH')
376 # these values can be "set"
380 upgrade downgrade precision accuracy round_mode div_scale/
383 $set_args->{$key} = $args->{$key} if exists $args->{$key};
384 delete $args->{$key};
389 Carp::croak ("Illegal key(s) '",
390 join("','",keys %$args),"' passed to $class\->config()");
392 foreach my $key (keys %$set_args)
394 if ($key =~ /^trap_(inf|nan)\z/)
396 ${"${class}::_trap_$1"} = ($set_args->{"trap_$1"} ? 1 : 0);
399 # use a call instead of just setting the $variable to check argument
400 $class->$key($set_args->{$key});
404 # now return actual configuration
408 lib_version => ${"${CALC}::VERSION"},
410 trap_nan => ${"${class}::_trap_nan"},
411 trap_inf => ${"${class}::_trap_inf"},
412 version => ${"${class}::VERSION"},
415 upgrade downgrade precision accuracy round_mode div_scale
418 $cfg->{$key} = ${"${class}::$key"};
425 # select accuracy parameter based on precedence,
426 # used by bround() and bfround(), may return undef for scale (means no op)
427 my ($x,$scale,$mode) = @_;
429 $scale = $x->{_a} unless defined $scale;
434 $scale = ${ $class . '::accuracy' } unless defined $scale;
435 $mode = ${ $class . '::round_mode' } unless defined $mode;
442 # select precision parameter based on precedence,
443 # used by bround() and bfround(), may return undef for scale (means no op)
444 my ($x,$scale,$mode) = @_;
446 $scale = $x->{_p} unless defined $scale;
451 $scale = ${ $class . '::precision' } unless defined $scale;
452 $mode = ${ $class . '::round_mode' } unless defined $mode;
457 ##############################################################################
465 # if two arguments, the first one is the class to "swallow" subclasses
473 return unless ref($x); # only for objects
475 my $self = bless {}, $c;
477 $self->{sign} = $x->{sign};
478 $self->{value} = $CALC->_copy($x->{value});
479 $self->{_a} = $x->{_a} if defined $x->{_a};
480 $self->{_p} = $x->{_p} if defined $x->{_p};
486 # create a new BigInt object from a string or another BigInt object.
487 # see hash keys documented at top
489 # the argument could be an object, so avoid ||, && etc on it, this would
490 # cause costly overloaded code to be called. The only allowed ops are
493 my ($class,$wanted,$a,$p,$r) = @_;
495 # avoid numify-calls by not using || on $wanted!
496 return $class->bzero($a,$p) if !defined $wanted; # default to 0
497 return $class->copy($wanted,$a,$p,$r)
498 if ref($wanted) && $wanted->isa($class); # MBI or subclass
500 $class->import() if $IMPORT == 0; # make require work
502 my $self = bless {}, $class;
504 # shortcut for "normal" numbers
505 if ((!ref $wanted) && ($wanted =~ /^([+-]?)[1-9][0-9]*\z/))
507 $self->{sign} = $1 || '+';
509 if ($wanted =~ /^[+-]/)
511 # remove sign without touching wanted to make it work with constants
512 my $t = $wanted; $t =~ s/^[+-]//;
513 $self->{value} = $CALC->_new($t);
517 $self->{value} = $CALC->_new($wanted);
520 if ( (defined $a) || (defined $p)
521 || (defined ${"${class}::precision"})
522 || (defined ${"${class}::accuracy"})
525 $self->round($a,$p,$r) unless (@_ == 4 && !defined $a && !defined $p);
530 # handle '+inf', '-inf' first
531 if ($wanted =~ /^[+-]?inf$/)
533 $self->{value} = $CALC->_zero();
534 $self->{sign} = $wanted; $self->{sign} = '+inf' if $self->{sign} eq 'inf';
537 # split str in m mantissa, e exponent, i integer, f fraction, v value, s sign
538 my ($mis,$miv,$mfv,$es,$ev) = _split($wanted);
543 require Carp; Carp::croak("$wanted is not a number in $class");
545 $self->{value} = $CALC->_zero();
546 $self->{sign} = $nan;
551 # _from_hex or _from_bin
552 $self->{value} = $mis->{value};
553 $self->{sign} = $mis->{sign};
554 return $self; # throw away $mis
556 # make integer from mantissa by adjusting exp, then convert to bigint
557 $self->{sign} = $$mis; # store sign
558 $self->{value} = $CALC->_zero(); # for all the NaN cases
559 my $e = int("$$es$$ev"); # exponent (avoid recursion)
562 my $diff = $e - CORE::length($$mfv);
563 if ($diff < 0) # Not integer
567 require Carp; Carp::croak("$wanted not an integer in $class");
570 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
571 $self->{sign} = $nan;
575 # adjust fraction and add it to value
576 #print "diff > 0 $$miv\n";
577 $$miv = $$miv . ($$mfv . '0' x $diff);
582 if ($$mfv ne '') # e <= 0
584 # fraction and negative/zero E => NOI
587 require Carp; Carp::croak("$wanted not an integer in $class");
589 #print "NOI 2 \$\$mfv '$$mfv'\n";
590 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
591 $self->{sign} = $nan;
595 # xE-y, and empty mfv
598 if ($$miv !~ s/0{$e}$//) # can strip so many zero's?
602 require Carp; Carp::croak("$wanted not an integer in $class");
605 return $upgrade->new($wanted,$a,$p,$r) if defined $upgrade;
606 $self->{sign} = $nan;
610 $self->{sign} = '+' if $$miv eq '0'; # normalize -0 => +0
611 $self->{value} = $CALC->_new($$miv) if $self->{sign} =~ /^[+-]$/;
612 # if any of the globals is set, use them to round and store them inside $self
613 # do not round for new($x,undef,undef) since that is used by MBF to signal
615 $self->round($a,$p,$r) unless @_ == 4 && !defined $a && !defined $p;
621 # create a bigint 'NaN', if given a BigInt, set it to 'NaN'
623 $self = $class if !defined $self;
626 my $c = $self; $self = {}; bless $self, $c;
629 if (${"${class}::_trap_nan"})
632 Carp::croak ("Tried to set $self to NaN in $class\::bnan()");
634 $self->import() if $IMPORT == 0; # make require work
635 return if $self->modify('bnan');
636 if ($self->can('_bnan'))
638 # use subclass to initialize
643 # otherwise do our own thing
644 $self->{value} = $CALC->_zero();
646 $self->{sign} = $nan;
647 delete $self->{_a}; delete $self->{_p}; # rounding NaN is silly
653 # create a bigint '+-inf', if given a BigInt, set it to '+-inf'
654 # the sign is either '+', or if given, used from there
656 my $sign = shift; $sign = '+' if !defined $sign || $sign !~ /^-(inf)?$/;
657 $self = $class if !defined $self;
660 my $c = $self; $self = {}; bless $self, $c;
663 if (${"${class}::_trap_inf"})
666 Carp::croak ("Tried to set $self to +-inf in $class\::binfn()");
668 $self->import() if $IMPORT == 0; # make require work
669 return if $self->modify('binf');
670 if ($self->can('_binf'))
672 # use subclass to initialize
677 # otherwise do our own thing
678 $self->{value} = $CALC->_zero();
680 $sign = $sign . 'inf' if $sign !~ /inf$/; # - => -inf
681 $self->{sign} = $sign;
682 ($self->{_a},$self->{_p}) = @_; # take over requested rounding
688 # create a bigint '+0', if given a BigInt, set it to 0
690 $self = __PACKAGE__ if !defined $self;
694 my $c = $self; $self = {}; bless $self, $c;
696 $self->import() if $IMPORT == 0; # make require work
697 return if $self->modify('bzero');
699 if ($self->can('_bzero'))
701 # use subclass to initialize
706 # otherwise do our own thing
707 $self->{value} = $CALC->_zero();
714 # call like: $x->bzero($a,$p,$r,$y);
715 ($self,$self->{_a},$self->{_p}) = $self->_find_round_parameters(@_);
720 if ( (!defined $self->{_a}) || (defined $_[0] && $_[0] > $self->{_a}));
722 if ( (!defined $self->{_p}) || (defined $_[1] && $_[1] > $self->{_p}));
730 # create a bigint '+1' (or -1 if given sign '-'),
731 # if given a BigInt, set it to +1 or -1, respecively
733 my $sign = shift; $sign = '+' if !defined $sign || $sign ne '-';
734 $self = $class if !defined $self;
738 my $c = $self; $self = {}; bless $self, $c;
740 $self->import() if $IMPORT == 0; # make require work
741 return if $self->modify('bone');
743 if ($self->can('_bone'))
745 # use subclass to initialize
750 # otherwise do our own thing
751 $self->{value} = $CALC->_one();
753 $self->{sign} = $sign;
758 # call like: $x->bone($sign,$a,$p,$r,$y);
759 ($self,$self->{_a},$self->{_p}) = $self->_find_round_parameters(@_);
763 # call like: $x->bone($sign,$a,$p,$r);
765 if ( (!defined $self->{_a}) || (defined $_[0] && $_[0] > $self->{_a}));
767 if ( (!defined $self->{_p}) || (defined $_[1] && $_[1] > $self->{_p}));
773 ##############################################################################
774 # string conversation
778 # (ref to BFLOAT or num_str ) return num_str
779 # Convert number from internal format to scientific string format.
780 # internal format is always normalized (no leading zeros, "-0E0" => "+0E0")
781 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
783 if ($x->{sign} !~ /^[+-]$/)
785 return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
788 my ($m,$e) = $x->parts();
789 #$m->bstr() . 'e+' . $e->bstr(); # e can only be positive in BigInt
790 # 'e+' because E can only be positive in BigInt
791 $m->bstr() . 'e+' . $CALC->_str($e->{value});
796 # make a string from bigint object
797 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
799 if ($x->{sign} !~ /^[+-]$/)
801 return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
804 my $es = ''; $es = $x->{sign} if $x->{sign} eq '-';
805 $es.$CALC->_str($x->{value});
810 # Make a "normal" scalar from a BigInt object
811 my $x = shift; $x = $class->new($x) unless ref $x;
813 return $x->bstr() if $x->{sign} !~ /^[+-]$/;
814 my $num = $CALC->_num($x->{value});
815 return -$num if $x->{sign} eq '-';
819 ##############################################################################
820 # public stuff (usually prefixed with "b")
824 # return the sign of the number: +/-/-inf/+inf/NaN
825 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
830 sub _find_round_parameters
832 # After any operation or when calling round(), the result is rounded by
833 # regarding the A & P from arguments, local parameters, or globals.
835 # !!!!!!! If you change this, remember to change round(), too! !!!!!!!!!!
837 # This procedure finds the round parameters, but it is for speed reasons
838 # duplicated in round. Otherwise, it is tested by the testsuite and used
841 # returns ($self) or ($self,$a,$p,$r) - sets $self to NaN of both A and P
842 # were requested/defined (locally or globally or both)
844 my ($self,$a,$p,$r,@args) = @_;
845 # $a accuracy, if given by caller
846 # $p precision, if given by caller
847 # $r round_mode, if given by caller
848 # @args all 'other' arguments (0 for unary, 1 for binary ops)
850 my $c = ref($self); # find out class of argument(s)
853 # now pick $a or $p, but only if we have got "arguments"
856 foreach ($self,@args)
858 # take the defined one, or if both defined, the one that is smaller
859 $a = $_->{_a} if (defined $_->{_a}) && (!defined $a || $_->{_a} < $a);
864 # even if $a is defined, take $p, to signal error for both defined
865 foreach ($self,@args)
867 # take the defined one, or if both defined, the one that is bigger
869 $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} > $p);
872 # if still none defined, use globals (#2)
873 $a = ${"$c\::accuracy"} unless defined $a;
874 $p = ${"$c\::precision"} unless defined $p;
876 # A == 0 is useless, so undef it to signal no rounding
877 $a = undef if defined $a && $a == 0;
880 return ($self) unless defined $a || defined $p; # early out
882 # set A and set P is an fatal error
883 return ($self->bnan()) if defined $a && defined $p; # error
885 $r = ${"$c\::round_mode"} unless defined $r;
886 if ($r !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
888 require Carp; Carp::croak ("Unknown round mode '$r'");
896 # Round $self according to given parameters, or given second argument's
897 # parameters or global defaults
899 # for speed reasons, _find_round_parameters is embeded here:
901 my ($self,$a,$p,$r,@args) = @_;
902 # $a accuracy, if given by caller
903 # $p precision, if given by caller
904 # $r round_mode, if given by caller
905 # @args all 'other' arguments (0 for unary, 1 for binary ops)
907 my $c = ref($self); # find out class of argument(s)
910 # now pick $a or $p, but only if we have got "arguments"
913 foreach ($self,@args)
915 # take the defined one, or if both defined, the one that is smaller
916 $a = $_->{_a} if (defined $_->{_a}) && (!defined $a || $_->{_a} < $a);
921 # even if $a is defined, take $p, to signal error for both defined
922 foreach ($self,@args)
924 # take the defined one, or if both defined, the one that is bigger
926 $p = $_->{_p} if (defined $_->{_p}) && (!defined $p || $_->{_p} > $p);
929 # if still none defined, use globals (#2)
930 $a = ${"$c\::accuracy"} unless defined $a;
931 $p = ${"$c\::precision"} unless defined $p;
933 # A == 0 is useless, so undef it to signal no rounding
934 $a = undef if defined $a && $a == 0;
937 return $self unless defined $a || defined $p; # early out
939 # set A and set P is an fatal error
940 return $self->bnan() if defined $a && defined $p;
942 $r = ${"$c\::round_mode"} unless defined $r;
943 if ($r !~ /^(even|odd|\+inf|\-inf|zero|trunc)$/)
945 require Carp; Carp::croak ("Unknown round mode '$r'");
948 # now round, by calling either fround or ffround:
951 $self->bround($a,$r) if !defined $self->{_a} || $self->{_a} >= $a;
953 else # both can't be undefined due to early out
955 $self->bfround($p,$r) if !defined $self->{_p} || $self->{_p} <= $p;
957 # bround() or bfround() already callled bnorm() if necc.
963 # (numstr or BINT) return BINT
964 # Normalize number -- no-op here
965 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
971 # (BINT or num_str) return BINT
972 # make number absolute, or return absolute BINT from string
973 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
975 return $x if $x->modify('babs');
976 # post-normalized abs for internal use (does nothing for NaN)
977 $x->{sign} =~ s/^-/+/;
983 # (BINT or num_str) return BINT
984 # negate number or make a negated number from string
985 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
987 return $x if $x->modify('bneg');
989 # for +0 dont negate (to have always normalized +0). Does nothing for 'NaN'
990 $x->{sign} =~ tr/+-/-+/ unless ($x->{sign} eq '+' && $CALC->_is_zero($x->{value}));
996 # Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort)
997 # (BINT or num_str, BINT or num_str) return cond_code
1000 my ($self,$x,$y) = (ref($_[0]),@_);
1002 # objectify is costly, so avoid it
1003 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1005 ($self,$x,$y) = objectify(2,@_);
1008 return $upgrade->bcmp($x,$y) if defined $upgrade &&
1009 ((!$x->isa($self)) || (!$y->isa($self)));
1011 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1013 # handle +-inf and NaN
1014 return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1015 return 0 if $x->{sign} eq $y->{sign} && $x->{sign} =~ /^[+-]inf$/;
1016 return +1 if $x->{sign} eq '+inf';
1017 return -1 if $x->{sign} eq '-inf';
1018 return -1 if $y->{sign} eq '+inf';
1021 # check sign for speed first
1022 return 1 if $x->{sign} eq '+' && $y->{sign} eq '-'; # does also 0 <=> -y
1023 return -1 if $x->{sign} eq '-' && $y->{sign} eq '+'; # does also -x <=> 0
1025 # have same sign, so compare absolute values. Don't make tests for zero here
1026 # because it's actually slower than testin in Calc (especially w/ Pari et al)
1028 # post-normalized compare for internal use (honors signs)
1029 if ($x->{sign} eq '+')
1031 # $x and $y both > 0
1032 return $CALC->_acmp($x->{value},$y->{value});
1036 $CALC->_acmp($y->{value},$x->{value}); # swaped acmp (lib returns 0,1,-1)
1041 # Compares 2 values, ignoring their signs.
1042 # Returns one of undef, <0, =0, >0. (suitable for sort)
1043 # (BINT, BINT) return cond_code
1046 my ($self,$x,$y) = (ref($_[0]),@_);
1047 # objectify is costly, so avoid it
1048 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1050 ($self,$x,$y) = objectify(2,@_);
1053 return $upgrade->bacmp($x,$y) if defined $upgrade &&
1054 ((!$x->isa($self)) || (!$y->isa($self)));
1056 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1058 # handle +-inf and NaN
1059 return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1060 return 0 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} =~ /^[+-]inf$/;
1061 return 1 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} !~ /^[+-]inf$/;
1064 $CALC->_acmp($x->{value},$y->{value}); # lib does only 0,1,-1
1069 # add second arg (BINT or string) to first (BINT) (modifies first)
1070 # return result as BINT
1073 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1074 # objectify is costly, so avoid it
1075 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1077 ($self,$x,$y,@r) = objectify(2,@_);
1080 return $x if $x->modify('badd');
1081 return $upgrade->badd($upgrade->new($x),$upgrade->new($y),@r) if defined $upgrade &&
1082 ((!$x->isa($self)) || (!$y->isa($self)));
1084 $r[3] = $y; # no push!
1085 # inf and NaN handling
1086 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1089 return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1091 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1093 # +inf++inf or -inf+-inf => same, rest is NaN
1094 return $x if $x->{sign} eq $y->{sign};
1097 # +-inf + something => +inf
1098 # something +-inf => +-inf
1099 $x->{sign} = $y->{sign}, return $x if $y->{sign} =~ /^[+-]inf$/;
1103 my ($sx, $sy) = ( $x->{sign}, $y->{sign} ); # get signs
1107 $x->{value} = $CALC->_add($x->{value},$y->{value}); # same sign, abs add
1111 my $a = $CALC->_acmp ($y->{value},$x->{value}); # absolute compare
1114 $x->{value} = $CALC->_sub($y->{value},$x->{value},1); # abs sub w/ swap
1119 # speedup, if equal, set result to 0
1120 $x->{value} = $CALC->_zero();
1125 $x->{value} = $CALC->_sub($x->{value}, $y->{value}); # abs sub
1133 # (BINT or num_str, BINT or num_str) return BINT
1134 # subtract second arg from first, modify first
1137 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1138 # objectify is costly, so avoid it
1139 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1141 ($self,$x,$y,@r) = objectify(2,@_);
1144 return $x if $x->modify('bsub');
1146 return $upgrade->new($x)->bsub($upgrade->new($y),@r) if defined $upgrade &&
1147 ((!$x->isa($self)) || (!$y->isa($self)));
1149 return $x->round(@r) if $y->is_zero();
1151 # To correctly handle the lone special case $x->bsub($x), we note the sign
1152 # of $x, then flip the sign from $y, and if the sign of $x did change, too,
1153 # then we caught the special case:
1154 my $xsign = $x->{sign};
1155 $y->{sign} =~ tr/+\-/-+/; # does nothing for NaN
1156 if ($xsign ne $x->{sign})
1158 # special case of $x->bsub($x) results in 0
1159 return $x->bzero(@r) if $xsign =~ /^[+-]$/;
1160 return $x->bnan(); # NaN, -inf, +inf
1162 $x->badd($y,@r); # badd does not leave internal zeros
1163 $y->{sign} =~ tr/+\-/-+/; # refix $y (does nothing for NaN)
1164 $x; # already rounded by badd() or no round necc.
1169 # increment arg by one
1170 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1171 return $x if $x->modify('binc');
1173 if ($x->{sign} eq '+')
1175 $x->{value} = $CALC->_inc($x->{value});
1176 return $x->round($a,$p,$r);
1178 elsif ($x->{sign} eq '-')
1180 $x->{value} = $CALC->_dec($x->{value});
1181 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # -1 +1 => -0 => +0
1182 return $x->round($a,$p,$r);
1184 # inf, nan handling etc
1185 $x->badd($self->bone(),$a,$p,$r); # badd does round
1190 # decrement arg by one
1191 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1192 return $x if $x->modify('bdec');
1194 if ($x->{sign} eq '-')
1197 $x->{value} = $CALC->_inc($x->{value});
1201 return $x->badd($self->bone('-'),@r) unless $x->{sign} eq '+'; # inf or NaN
1203 if ($CALC->_is_zero($x->{value}))
1206 $x->{value} = $CALC->_one(); $x->{sign} = '-'; # 0 => -1
1211 $x->{value} = $CALC->_dec($x->{value});
1219 # calculate $x = $a ** $base + $b and return $a (e.g. the log() to base
1223 my ($self,$x,$base,@r) = (undef,@_);
1224 # objectify is costly, so avoid it
1225 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1227 ($self,$x,$base,@r) = objectify(1,ref($x),@_);
1230 return $x if $x->modify('blog');
1232 # inf, -inf, NaN, <0 => NaN
1234 if $x->{sign} ne '+' || (defined $base && $base->{sign} ne '+');
1236 return $upgrade->blog($upgrade->new($x),$base,@r) if
1239 my ($rc,$exact) = $CALC->_log_int($x->{value},$base->{value});
1240 return $x->bnan() unless defined $rc; # not possible to take log?
1247 # (BINT or num_str, BINT or num_str) return BINT
1248 # does not modify arguments, but returns new object
1249 # Lowest Common Multiplicator
1251 my $y = shift; my ($x);
1258 $x = $class->new($y);
1263 my $y = shift; $y = $self->new($y) if !ref ($y);
1271 # (BINT or num_str, BINT or num_str) return BINT
1272 # does not modify arguments, but returns new object
1273 # GCD -- Euclids algorithm, variant C (Knuth Vol 3, pg 341 ff)
1276 $y = $class->new($y) if !ref($y);
1278 my $x = $y->copy()->babs(); # keep arguments
1279 return $x->bnan() if $x->{sign} !~ /^[+-]$/; # x NaN?
1283 $y = shift; $y = $self->new($y) if !ref($y);
1284 return $x->bnan() if $y->{sign} !~ /^[+-]$/; # y NaN?
1285 $x->{value} = $CALC->_gcd($x->{value},$y->{value});
1286 last if $CALC->_is_one($x->{value});
1293 # (num_str or BINT) return BINT
1294 # represent ~x as twos-complement number
1295 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1296 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1298 return $x if $x->modify('bnot');
1299 $x->binc()->bneg(); # binc already does round
1302 ##############################################################################
1303 # is_foo test routines
1304 # we don't need $self, so undef instead of ref($_[0]) make it slightly faster
1308 # return true if arg (BINT or num_str) is zero (array '+', '0')
1309 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1311 return 0 if $x->{sign} !~ /^\+$/; # -, NaN & +-inf aren't
1312 $CALC->_is_zero($x->{value});
1317 # return true if arg (BINT or num_str) is NaN
1318 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1320 $x->{sign} eq $nan ? 1 : 0;
1325 # return true if arg (BINT or num_str) is +-inf
1326 my ($self,$x,$sign) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1330 $sign = '[+-]inf' if $sign eq ''; # +- doesn't matter, only that's inf
1331 $sign = "[$1]inf" if $sign =~ /^([+-])(inf)?$/; # extract '+' or '-'
1332 return $x->{sign} =~ /^$sign$/ ? 1 : 0;
1334 $x->{sign} =~ /^[+-]inf$/ ? 1 : 0; # only +-inf is infinity
1339 # return true if arg (BINT or num_str) is +1, or -1 if sign is given
1340 my ($self,$x,$sign) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1342 $sign = '+' if !defined $sign || $sign ne '-';
1344 return 0 if $x->{sign} ne $sign; # -1 != +1, NaN, +-inf aren't either
1345 $CALC->_is_one($x->{value});
1350 # return true when arg (BINT or num_str) is odd, false for even
1351 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1353 return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
1354 $CALC->_is_odd($x->{value});
1359 # return true when arg (BINT or num_str) is even, false for odd
1360 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1362 return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
1363 $CALC->_is_even($x->{value});
1368 # return true when arg (BINT or num_str) is positive (>= 0)
1369 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1371 return 1 if $x->{sign} eq '+inf'; # +inf is positive
1373 # 0+ is neither positive nor negative
1374 ($x->{sign} eq '+' && !$x->is_zero()) ? 1 : 0;
1379 # return true when arg (BINT or num_str) is negative (< 0)
1380 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1382 $x->{sign} =~ /^-/ ? 1 : 0; # -inf is negative, but NaN is not
1387 # return true when arg (BINT or num_str) is an integer
1388 # always true for BigInt, but different for BigFloats
1389 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1391 $x->{sign} =~ /^[+-]$/ ? 1 : 0; # inf/-inf/NaN aren't
1394 ###############################################################################
1398 # multiply two numbers -- stolen from Knuth Vol 2 pg 233
1399 # (BINT or num_str, BINT or num_str) return BINT
1402 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1403 # objectify is costly, so avoid it
1404 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1406 ($self,$x,$y,@r) = objectify(2,@_);
1409 return $x if $x->modify('bmul');
1411 return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1414 if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
1416 return $x->bnan() if $x->is_zero() || $y->is_zero();
1417 # result will always be +-inf:
1418 # +inf * +/+inf => +inf, -inf * -/-inf => +inf
1419 # +inf * -/-inf => -inf, -inf * +/+inf => -inf
1420 return $x->binf() if ($x->{sign} =~ /^\+/ && $y->{sign} =~ /^\+/);
1421 return $x->binf() if ($x->{sign} =~ /^-/ && $y->{sign} =~ /^-/);
1422 return $x->binf('-');
1425 return $upgrade->bmul($x,$upgrade->new($y),@r)
1426 if defined $upgrade && !$y->isa($self);
1428 $r[3] = $y; # no push here
1430 $x->{sign} = $x->{sign} eq $y->{sign} ? '+' : '-'; # +1 * +1 or -1 * -1 => +
1432 $x->{value} = $CALC->_mul($x->{value},$y->{value}); # do actual math
1433 $x->{sign} = '+' if $CALC->_is_zero($x->{value}); # no -0
1440 # helper function that handles +-inf cases for bdiv()/bmod() to reuse code
1441 my ($self,$x,$y) = @_;
1443 # NaN if x == NaN or y == NaN or x==y==0
1444 return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan()
1445 if (($x->is_nan() || $y->is_nan()) ||
1446 ($x->is_zero() && $y->is_zero()));
1448 # +-inf / +-inf == NaN, reminder also NaN
1449 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1451 return wantarray ? ($x->bnan(),$self->bnan()) : $x->bnan();
1453 # x / +-inf => 0, remainder x (works even if x == 0)
1454 if ($y->{sign} =~ /^[+-]inf$/)
1456 my $t = $x->copy(); # bzero clobbers up $x
1457 return wantarray ? ($x->bzero(),$t) : $x->bzero()
1460 # 5 / 0 => +inf, -6 / 0 => -inf
1461 # +inf / 0 = inf, inf, and -inf / 0 => -inf, -inf
1462 # exception: -8 / 0 has remainder -8, not 8
1463 # exception: -inf / 0 has remainder -inf, not inf
1466 # +-inf / 0 => special case for -inf
1467 return wantarray ? ($x,$x->copy()) : $x if $x->is_inf();
1468 if (!$x->is_zero() && !$x->is_inf())
1470 my $t = $x->copy(); # binf clobbers up $x
1472 ($x->binf($x->{sign}),$t) : $x->binf($x->{sign})
1476 # last case: +-inf / ordinary number
1478 $sign = '-inf' if substr($x->{sign},0,1) ne $y->{sign};
1480 return wantarray ? ($x,$self->bzero()) : $x;
1485 # (dividend: BINT or num_str, divisor: BINT or num_str) return
1486 # (BINT,BINT) (quo,rem) or BINT (only rem)
1489 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1490 # objectify is costly, so avoid it
1491 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1493 ($self,$x,$y,@r) = objectify(2,@_);
1496 return $x if $x->modify('bdiv');
1498 return $self->_div_inf($x,$y)
1499 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero());
1501 return $upgrade->bdiv($upgrade->new($x),$upgrade->new($y),@r)
1502 if defined $upgrade;
1504 $r[3] = $y; # no push!
1506 # calc new sign and in case $y == +/- 1, return $x
1507 my $xsign = $x->{sign}; # keep
1508 $x->{sign} = ($x->{sign} ne $y->{sign} ? '-' : '+');
1512 my $rem = $self->bzero();
1513 ($x->{value},$rem->{value}) = $CALC->_div($x->{value},$y->{value});
1514 $x->{sign} = '+' if $CALC->_is_zero($x->{value});
1515 $rem->{_a} = $x->{_a};
1516 $rem->{_p} = $x->{_p};
1518 if (! $CALC->_is_zero($rem->{value}))
1520 $rem->{sign} = $y->{sign};
1521 $rem = $y->copy()->bsub($rem) if $xsign ne $y->{sign}; # one of them '-'
1525 $rem->{sign} = '+'; # dont leave -0
1531 $x->{value} = $CALC->_div($x->{value},$y->{value});
1532 $x->{sign} = '+' if $CALC->_is_zero($x->{value});
1537 ###############################################################################
1542 # modulus (or remainder)
1543 # (BINT or num_str, BINT or num_str) return BINT
1546 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1547 # objectify is costly, so avoid it
1548 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1550 ($self,$x,$y,@r) = objectify(2,@_);
1553 return $x if $x->modify('bmod');
1554 $r[3] = $y; # no push!
1555 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero())
1557 my ($d,$r) = $self->_div_inf($x,$y);
1558 $x->{sign} = $r->{sign};
1559 $x->{value} = $r->{value};
1560 return $x->round(@r);
1563 # calc new sign and in case $y == +/- 1, return $x
1564 $x->{value} = $CALC->_mod($x->{value},$y->{value});
1565 if (!$CALC->_is_zero($x->{value}))
1567 $x->{value} = $CALC->_sub($y->{value},$x->{value},1) # $y-$x
1568 if ($x->{sign} ne $y->{sign});
1569 $x->{sign} = $y->{sign};
1573 $x->{sign} = '+'; # dont leave -0
1580 # Modular inverse. given a number which is (hopefully) relatively
1581 # prime to the modulus, calculate its inverse using Euclid's
1582 # alogrithm. If the number is not relatively prime to the modulus
1583 # (i.e. their gcd is not one) then NaN is returned.
1586 my ($self,$x,$y,@r) = (undef,@_);
1587 # objectify is costly, so avoid it
1588 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1590 ($self,$x,$y,@r) = objectify(2,@_);
1593 return $x if $x->modify('bmodinv');
1596 if ($y->{sign} ne '+' # -, NaN, +inf, -inf
1597 || $x->is_zero() # or num == 0
1598 || $x->{sign} !~ /^[+-]$/ # or num NaN, inf, -inf
1601 # put least residue into $x if $x was negative, and thus make it positive
1602 $x->bmod($y) if $x->{sign} eq '-';
1605 ($x->{value},$sign) = $CALC->_modinv($x->{value},$y->{value});
1606 return $x->bnan() if !defined $x->{value}; # in case no GCD found
1607 return $x if !defined $sign; # already real result
1608 $x->{sign} = $sign; # flip/flop see below
1609 $x->bmod($y); # calc real result
1615 # takes a very large number to a very large exponent in a given very
1616 # large modulus, quickly, thanks to binary exponentation. supports
1617 # negative exponents.
1618 my ($self,$num,$exp,$mod,@r) = objectify(3,@_);
1620 return $num if $num->modify('bmodpow');
1622 # check modulus for valid values
1623 return $num->bnan() if ($mod->{sign} ne '+' # NaN, - , -inf, +inf
1624 || $mod->is_zero());
1626 # check exponent for valid values
1627 if ($exp->{sign} =~ /\w/)
1629 # i.e., if it's NaN, +inf, or -inf...
1630 return $num->bnan();
1633 $num->bmodinv ($mod) if ($exp->{sign} eq '-');
1635 # check num for valid values (also NaN if there was no inverse but $exp < 0)
1636 return $num->bnan() if $num->{sign} !~ /^[+-]$/;
1638 # $mod is positive, sign on $exp is ignored, result also positive
1639 $num->{value} = $CALC->_modpow($num->{value},$exp->{value},$mod->{value});
1643 ###############################################################################
1647 # (BINT or num_str, BINT or num_str) return BINT
1648 # compute factorial number from $x, modify $x in place
1649 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1651 return $x if $x->modify('bfac') || $x->{sign} eq '+inf'; # inf => inf
1652 return $x->bnan() if $x->{sign} ne '+'; # NaN, <0 etc => NaN
1654 $x->{value} = $CALC->_fac($x->{value});
1660 # (BINT or num_str, BINT or num_str) return BINT
1661 # compute power of two numbers -- stolen from Knuth Vol 2 pg 233
1662 # modifies first argument
1665 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1666 # objectify is costly, so avoid it
1667 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1669 ($self,$x,$y,@r) = objectify(2,@_);
1672 return $x if $x->modify('bpow');
1674 return $x->bnan() if $x->{sign} eq $nan || $y->{sign} eq $nan;
1677 if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
1679 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
1685 if ($x->{sign} =~ /^[+-]inf/)
1688 return $x->bnan() if $y->is_zero();
1689 # -inf ** -1 => 1/inf => 0
1690 return $x->bzero() if $y->is_one('-') && $x->is_negative();
1693 return $x if $x->{sign} eq '+inf';
1695 # -inf ** Y => -inf if Y is odd
1696 return $x if $y->is_odd();
1702 return $x if $x->is_one();
1705 return $x if $x->is_zero() && $y->{sign} =~ /^[+]/;
1708 return $x->binf() if $x->is_zero();
1711 return $x->bnan() if $x->is_one('-') && $y->{sign} =~ /^[-]/;
1714 return $x->bzero() if $x->{sign} eq '-' && $y->{sign} =~ /^[-]/;
1717 return $x->bnan() if $x->{sign} eq '-';
1720 return $x->binf() if $y->{sign} =~ /^[+]/;
1725 return $upgrade->bpow($upgrade->new($x),$y,@r)
1726 if defined $upgrade && !$y->isa($self);
1728 $r[3] = $y; # no push!
1730 # cases 0 ** Y, X ** 0, X ** 1, 1 ** Y are handled by Calc or Emu
1733 $new_sign = $y->is_odd() ? '-' : '+' if ($x->{sign} ne '+');
1735 # 0 ** -7 => ( 1 / (0 ** 7)) => 1 / 0 => +inf
1737 if $y->{sign} eq '-' && $x->{sign} eq '+' && $CALC->_is_zero($x->{value});
1738 # 1 ** -y => 1 / (1 ** |y|)
1739 # so do test for negative $y after above's clause
1740 return $x->bnan() if $y->{sign} eq '-' && !$CALC->_is_one($x->{value});
1742 $x->{value} = $CALC->_pow($x->{value},$y->{value});
1743 $x->{sign} = $new_sign;
1744 $x->{sign} = '+' if $CALC->_is_zero($y->{value});
1750 # (BINT or num_str, BINT or num_str) return BINT
1751 # compute x << y, base n, y >= 0
1754 my ($self,$x,$y,$n,@r) = (ref($_[0]),@_);
1755 # objectify is costly, so avoid it
1756 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1758 ($self,$x,$y,$n,@r) = objectify(2,@_);
1761 return $x if $x->modify('blsft');
1762 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1763 return $x->round(@r) if $y->is_zero();
1765 $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
1767 $x->{value} = $CALC->_lsft($x->{value},$y->{value},$n);
1773 # (BINT or num_str, BINT or num_str) return BINT
1774 # compute x >> y, base n, y >= 0
1777 my ($self,$x,$y,$n,@r) = (ref($_[0]),@_);
1778 # objectify is costly, so avoid it
1779 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1781 ($self,$x,$y,$n,@r) = objectify(2,@_);
1784 return $x if $x->modify('brsft');
1785 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1786 return $x->round(@r) if $y->is_zero();
1787 return $x->bzero(@r) if $x->is_zero(); # 0 => 0
1789 $n = 2 if !defined $n; return $x->bnan() if $n <= 0 || $y->{sign} eq '-';
1791 # this only works for negative numbers when shifting in base 2
1792 if (($x->{sign} eq '-') && ($n == 2))
1794 return $x->round(@r) if $x->is_one('-'); # -1 => -1
1797 # although this is O(N*N) in calc (as_bin!) it is O(N) in Pari et al
1798 # but perhaps there is a better emulation for two's complement shift...
1799 # if $y != 1, we must simulate it by doing:
1800 # convert to bin, flip all bits, shift, and be done
1801 $x->binc(); # -3 => -2
1802 my $bin = $x->as_bin();
1803 $bin =~ s/^-0b//; # strip '-0b' prefix
1804 $bin =~ tr/10/01/; # flip bits
1806 if (CORE::length($bin) <= $y)
1808 $bin = '0'; # shifting to far right creates -1
1809 # 0, because later increment makes
1810 # that 1, attached '-' makes it '-1'
1811 # because -1 >> x == -1 !
1815 $bin =~ s/.{$y}$//; # cut off at the right side
1816 $bin = '1' . $bin; # extend left side by one dummy '1'
1817 $bin =~ tr/10/01/; # flip bits back
1819 my $res = $self->new('0b'.$bin); # add prefix and convert back
1820 $res->binc(); # remember to increment
1821 $x->{value} = $res->{value}; # take over value
1822 return $x->round(@r); # we are done now, magic, isn't?
1824 # x < 0, n == 2, y == 1
1825 $x->bdec(); # n == 2, but $y == 1: this fixes it
1828 $x->{value} = $CALC->_rsft($x->{value},$y->{value},$n);
1834 #(BINT or num_str, BINT or num_str) return BINT
1838 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1839 # objectify is costly, so avoid it
1840 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1842 ($self,$x,$y,@r) = objectify(2,@_);
1845 return $x if $x->modify('band');
1847 $r[3] = $y; # no push!
1849 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1851 my $sx = $x->{sign} eq '+' ? 1 : -1;
1852 my $sy = $y->{sign} eq '+' ? 1 : -1;
1854 if ($sx == 1 && $sy == 1)
1856 $x->{value} = $CALC->_and($x->{value},$y->{value});
1857 return $x->round(@r);
1860 if ($CAN{signed_and})
1862 $x->{value} = $CALC->_signed_and($x->{value},$y->{value},$sx,$sy);
1863 return $x->round(@r);
1867 __emu_band($self,$x,$y,$sx,$sy,@r);
1872 #(BINT or num_str, BINT or num_str) return BINT
1876 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1877 # objectify is costly, so avoid it
1878 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1880 ($self,$x,$y,@r) = objectify(2,@_);
1883 return $x if $x->modify('bior');
1884 $r[3] = $y; # no push!
1886 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1888 my $sx = $x->{sign} eq '+' ? 1 : -1;
1889 my $sy = $y->{sign} eq '+' ? 1 : -1;
1891 # the sign of X follows the sign of X, e.g. sign of Y irrelevant for bior()
1893 # don't use lib for negative values
1894 if ($sx == 1 && $sy == 1)
1896 $x->{value} = $CALC->_or($x->{value},$y->{value});
1897 return $x->round(@r);
1900 # if lib can do negative values, let it handle this
1901 if ($CAN{signed_or})
1903 $x->{value} = $CALC->_signed_or($x->{value},$y->{value},$sx,$sy);
1904 return $x->round(@r);
1908 __emu_bior($self,$x,$y,$sx,$sy,@r);
1913 #(BINT or num_str, BINT or num_str) return BINT
1917 my ($self,$x,$y,@r) = (ref($_[0]),@_);
1918 # objectify is costly, so avoid it
1919 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1921 ($self,$x,$y,@r) = objectify(2,@_);
1924 return $x if $x->modify('bxor');
1925 $r[3] = $y; # no push!
1927 return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/);
1929 my $sx = $x->{sign} eq '+' ? 1 : -1;
1930 my $sy = $y->{sign} eq '+' ? 1 : -1;
1932 # don't use lib for negative values
1933 if ($sx == 1 && $sy == 1)
1935 $x->{value} = $CALC->_xor($x->{value},$y->{value});
1936 return $x->round(@r);
1939 # if lib can do negative values, let it handle this
1940 if ($CAN{signed_xor})
1942 $x->{value} = $CALC->_signed_xor($x->{value},$y->{value},$sx,$sy);
1943 return $x->round(@r);
1947 __emu_bxor($self,$x,$y,$sx,$sy,@r);
1952 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1954 my $e = $CALC->_len($x->{value});
1955 wantarray ? ($e,0) : $e;
1960 # return the nth decimal digit, negative values count backward, 0 is right
1961 my ($self,$x,$n) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1963 $n = $n->numify() if ref($n);
1964 $CALC->_digit($x->{value},$n||0);
1969 # return the amount of trailing zeros in $x (as scalar)
1971 $x = $class->new($x) unless ref $x;
1973 return 0 if $x->{sign} !~ /^[+-]$/; # NaN, inf, -inf etc
1975 $CALC->_zeros($x->{value}); # must handle odd values, 0 etc
1980 # calculate square root of $x
1981 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1983 return $x if $x->modify('bsqrt');
1985 return $x->bnan() if $x->{sign} !~ /^\+/; # -x or -inf or NaN => NaN
1986 return $x if $x->{sign} eq '+inf'; # sqrt(+inf) == inf
1988 return $upgrade->bsqrt($x,@r) if defined $upgrade;
1990 $x->{value} = $CALC->_sqrt($x->{value});
1996 # calculate $y'th root of $x
1999 my ($self,$x,$y,@r) = (ref($_[0]),@_);
2001 $y = $self->new(2) unless defined $y;
2003 # objectify is costly, so avoid it
2004 if ((!ref($x)) || (ref($x) ne ref($y)))
2006 ($self,$x,$y,@r) = objectify(2,$self || $class,@_);
2009 return $x if $x->modify('broot');
2011 # NaN handling: $x ** 1/0, x or y NaN, or y inf/-inf or y == 0
2012 return $x->bnan() if $x->{sign} !~ /^\+/ || $y->is_zero() ||
2013 $y->{sign} !~ /^\+$/;
2015 return $x->round(@r)
2016 if $x->is_zero() || $x->is_one() || $x->is_inf() || $y->is_one();
2018 return $upgrade->new($x)->broot($upgrade->new($y),@r) if defined $upgrade;
2020 $x->{value} = $CALC->_root($x->{value},$y->{value});
2026 # return a copy of the exponent (here always 0, NaN or 1 for $m == 0)
2027 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2029 if ($x->{sign} !~ /^[+-]$/)
2031 my $s = $x->{sign}; $s =~ s/^[+-]//; # NaN, -inf,+inf => NaN or inf
2032 return $self->new($s);
2034 return $self->bone() if $x->is_zero();
2036 $self->new($x->_trailing_zeros());
2041 # return the mantissa (compatible to Math::BigFloat, e.g. reduced)
2042 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2044 if ($x->{sign} !~ /^[+-]$/)
2046 # for NaN, +inf, -inf: keep the sign
2047 return $self->new($x->{sign});
2049 my $m = $x->copy(); delete $m->{_p}; delete $m->{_a};
2050 # that's a bit inefficient:
2051 my $zeros = $m->_trailing_zeros();
2052 $m->brsft($zeros,10) if $zeros != 0;
2058 # return a copy of both the exponent and the mantissa
2059 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
2061 ($x->mantissa(),$x->exponent());
2064 ##############################################################################
2065 # rounding functions
2069 # precision: round to the $Nth digit left (+$n) or right (-$n) from the '.'
2070 # $n == 0 || $n == 1 => round to integer
2071 my $x = shift; my $self = ref($x) || $x; $x = $self->new($x) unless ref $x;
2073 my ($scale,$mode) = $x->_scale_p(@_);
2075 return $x if !defined $scale || $x->modify('bfround'); # no-op
2077 # no-op for BigInts if $n <= 0
2078 $x->bround( $x->length()-$scale, $mode) if $scale > 0;
2080 delete $x->{_a}; # delete to save memory
2081 $x->{_p} = $scale; # store new _p
2085 sub _scan_for_nonzero
2087 # internal, used by bround() to scan for non-zeros after a '5'
2088 my ($x,$pad,$xs,$len) = @_;
2090 return 0 if $len == 1; # "5" is trailed by invisible zeros
2091 my $follow = $pad - 1;
2092 return 0 if $follow > $len || $follow < 1;
2094 # use the string form to check whether only '0's follow or not
2095 substr ($xs,-$follow) =~ /[^0]/ ? 1 : 0;
2100 # Exists to make life easier for switch between MBF and MBI (should we
2101 # autoload fxxx() like MBF does for bxxx()?)
2102 my $x = shift; $x = $class->new($x) unless ref $x;
2108 # accuracy: +$n preserve $n digits from left,
2109 # -$n preserve $n digits from right (f.i. for 0.1234 style in MBF)
2111 # and overwrite the rest with 0's, return normalized number
2112 # do not return $x->bnorm(), but $x
2114 my $x = shift; $x = $class->new($x) unless ref $x;
2115 my ($scale,$mode) = $x->_scale_a(@_);
2116 return $x if !defined $scale || $x->modify('bround'); # no-op
2118 if ($x->is_zero() || $scale == 0)
2120 $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale; # 3 > 2
2123 return $x if $x->{sign} !~ /^[+-]$/; # inf, NaN
2125 # we have fewer digits than we want to scale to
2126 my $len = $x->length();
2127 # convert $scale to a scalar in case it is an object (put's a limit on the
2128 # number length, but this would already limited by memory constraints), makes
2130 $scale = $scale->numify() if ref ($scale);
2132 # scale < 0, but > -len (not >=!)
2133 if (($scale < 0 && $scale < -$len-1) || ($scale >= $len))
2135 $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale; # 3 > 2
2139 # count of 0's to pad, from left (+) or right (-): 9 - +6 => 3, or |-6| => 6
2140 my ($pad,$digit_round,$digit_after);
2141 $pad = $len - $scale;
2142 $pad = abs($scale-1) if $scale < 0;
2144 # do not use digit(), it is very costly for binary => decimal
2145 # getting the entire string is also costly, but we need to do it only once
2146 my $xs = $CALC->_str($x->{value});
2149 # pad: 123: 0 => -1, at 1 => -2, at 2 => -3, at 3 => -4
2150 # pad+1: 123: 0 => 0, at 1 => -1, at 2 => -2, at 3 => -3
2151 $digit_round = '0'; $digit_round = substr($xs,$pl,1) if $pad <= $len;
2152 $pl++; $pl ++ if $pad >= $len;
2153 $digit_after = '0'; $digit_after = substr($xs,$pl,1) if $pad > 0;
2155 # in case of 01234 we round down, for 6789 up, and only in case 5 we look
2156 # closer at the remaining digits of the original $x, remember decision
2157 my $round_up = 1; # default round up
2159 ($mode eq 'trunc') || # trunc by round down
2160 ($digit_after =~ /[01234]/) || # round down anyway,
2162 ($digit_after eq '5') && # not 5000...0000
2163 ($x->_scan_for_nonzero($pad,$xs,$len) == 0) &&
2165 ($mode eq 'even') && ($digit_round =~ /[24680]/) ||
2166 ($mode eq 'odd') && ($digit_round =~ /[13579]/) ||
2167 ($mode eq '+inf') && ($x->{sign} eq '-') ||
2168 ($mode eq '-inf') && ($x->{sign} eq '+') ||
2169 ($mode eq 'zero') # round down if zero, sign adjusted below
2171 my $put_back = 0; # not yet modified
2173 if (($pad > 0) && ($pad <= $len))
2175 substr($xs,-$pad,$pad) = '0' x $pad; # replace with '00...'
2176 $put_back = 1; # need to put back
2180 $x->bzero(); # round to '0'
2183 if ($round_up) # what gave test above?
2185 $put_back = 1; # need to put back
2186 $pad = $len, $xs = '0' x $pad if $scale < 0; # tlr: whack 0.51=>1.0
2188 # we modify directly the string variant instead of creating a number and
2189 # adding it, since that is faster (we already have the string)
2190 my $c = 0; $pad ++; # for $pad == $len case
2191 while ($pad <= $len)
2193 $c = substr($xs,-$pad,1) + 1; $c = '0' if $c eq '10';
2194 substr($xs,-$pad,1) = $c; $pad++;
2195 last if $c != 0; # no overflow => early out
2197 $xs = '1'.$xs if $c == 0;
2200 $x->{value} = $CALC->_new($xs) if $put_back == 1; # put back, if needed
2202 $x->{_a} = $scale if $scale >= 0;
2205 $x->{_a} = $len+$scale;
2206 $x->{_a} = 0 if $scale < -$len;
2213 # return integer less or equal then number; no-op since it's already integer
2214 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2221 # return integer greater or equal then number; no-op since it's already int
2222 my ($self,$x,@r) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
2229 # An object might be asked to return itself as bigint on certain overloaded
2230 # operations, this does exactly this, so that sub classes can simple inherit
2231 # it or override with their own integer conversion routine.
2237 # return as hex string, with prefixed 0x
2238 my $x = shift; $x = $class->new($x) if !ref($x);
2240 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2243 $s = $x->{sign} if $x->{sign} eq '-';
2244 $s . $CALC->_as_hex($x->{value});
2249 # return as binary string, with prefixed 0b
2250 my $x = shift; $x = $class->new($x) if !ref($x);
2252 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2254 my $s = ''; $s = $x->{sign} if $x->{sign} eq '-';
2255 return $s . $CALC->_as_bin($x->{value});
2258 ##############################################################################
2259 # private stuff (internal use only)
2263 # check for strings, if yes, return objects instead
2265 # the first argument is number of args objectify() should look at it will
2266 # return $count+1 elements, the first will be a classname. This is because
2267 # overloaded '""' calls bstr($object,undef,undef) and this would result in
2268 # useless objects beeing created and thrown away. So we cannot simple loop
2269 # over @_. If the given count is 0, all arguments will be used.
2271 # If the second arg is a ref, use it as class.
2272 # If not, try to use it as classname, unless undef, then use $class
2273 # (aka Math::BigInt). The latter shouldn't happen,though.
2276 # $x->badd(1); => ref x, scalar y
2277 # Class->badd(1,2); => classname x (scalar), scalar x, scalar y
2278 # Class->badd( Class->(1),2); => classname x (scalar), ref x, scalar y
2279 # Math::BigInt::badd(1,2); => scalar x, scalar y
2280 # In the last case we check number of arguments to turn it silently into
2281 # $class,1,2. (We can not take '1' as class ;o)
2282 # badd($class,1) is not supported (it should, eventually, try to add undef)
2283 # currently it tries 'Math::BigInt' + 1, which will not work.
2285 # some shortcut for the common cases
2287 return (ref($_[1]),$_[1]) if (@_ == 2) && ($_[0]||0 == 1) && ref($_[1]);
2289 my $count = abs(shift || 0);
2291 my (@a,$k,$d); # resulting array, temp, and downgrade
2294 # okay, got object as first
2299 # nope, got 1,2 (Class->xxx(1) => Class,1 and not supported)
2301 $a[0] = shift if $_[0] =~ /^[A-Z].*::/; # classname as first?
2305 # disable downgrading, because Math::BigFLoat->foo('1.0','2.0') needs floats
2306 if (defined ${"$a[0]::downgrade"})
2308 $d = ${"$a[0]::downgrade"};
2309 ${"$a[0]::downgrade"} = undef;
2312 my $up = ${"$a[0]::upgrade"};
2313 #print "Now in objectify, my class is today $a[0], count = $count\n";
2321 $k = $a[0]->new($k);
2323 elsif (!defined $up && ref($k) ne $a[0])
2325 # foreign object, try to convert to integer
2326 $k->can('as_number') ? $k = $k->as_number() : $k = $a[0]->new($k);
2339 $k = $a[0]->new($k);
2341 elsif (!defined $up && ref($k) ne $a[0])
2343 # foreign object, try to convert to integer
2344 $k->can('as_number') ? $k = $k->as_number() : $k = $a[0]->new($k);
2348 push @a,@_; # return other params, too
2352 require Carp; Carp::croak ("$class objectify needs list context");
2354 ${"$a[0]::downgrade"} = $d;
2358 sub _register_callback
2360 my ($class,$callback) = @_;
2362 if (ref($callback) ne 'CODE')
2365 Carp::croak ("$callback is not a coderef");
2367 $CALLBACKS{$class} = $callback;
2374 $IMPORT++; # remember we did import()
2375 my @a; my $l = scalar @_;
2376 for ( my $i = 0; $i < $l ; $i++ )
2378 if ($_[$i] eq ':constant')
2380 # this causes overlord er load to step in
2382 integer => sub { $self->new(shift) },
2383 binary => sub { $self->new(shift) };
2385 elsif ($_[$i] eq 'upgrade')
2387 # this causes upgrading
2388 $upgrade = $_[$i+1]; # or undef to disable
2391 elsif ($_[$i] =~ /^lib$/i)
2393 # this causes a different low lib to take care...
2394 $CALC = $_[$i+1] || '';
2402 # any non :constant stuff is handled by our parent, Exporter
2407 $self->SUPER::import(@a); # need it for subclasses
2408 $self->export_to_level(1,$self,@a); # need it for MBF
2411 # try to load core math lib
2412 my @c = split /\s*,\s*/,$CALC;
2415 $_ =~ tr/a-zA-Z0-9://cd; # limit to sane characters
2417 push @c,'Calc'; # if all fail, try this
2418 $CALC = ''; # signal error
2419 foreach my $lib (@c)
2421 next if ($lib || '') eq '';
2422 $lib = 'Math::BigInt::'.$lib if $lib !~ /^Math::BigInt/i;
2426 # Perl < 5.6.0 dies with "out of memory!" when eval("") and ':constant' is
2427 # used in the same script, or eval("") inside import().
2428 my @parts = split /::/, $lib; # Math::BigInt => Math BigInt
2429 my $file = pop @parts; $file .= '.pm'; # BigInt => BigInt.pm
2431 $file = File::Spec->catfile (@parts, $file);
2432 eval { require "$file"; $lib->import( @c ); }
2436 eval "use $lib qw/@c/;";
2441 # loaded it ok, see if the api_version() is high enough
2442 if ($lib->can('api_version') && $lib->api_version() >= 1.0)
2445 # api_version matches, check if it really provides anything we need
2449 add mul div sub dec inc
2450 acmp len digit is_one is_zero is_even is_odd
2452 new copy check from_hex from_bin as_hex as_bin zeros
2453 rsft lsft xor and or
2454 mod sqrt root fac pow modinv modpow log_int gcd
2457 if (!$lib->can("_$method"))
2459 if (($WARN{$lib}||0) < 2)
2462 Carp::carp ("$lib is missing method '_$method'");
2463 $WARN{$lib} = 1; # still warn about the lib
2472 last; # found a usable one, break
2476 if (($WARN{$lib}||0) < 2)
2478 my $ver = eval "\$$lib\::VERSION" || 'unknown';
2480 Carp::carp ("Cannot load outdated $lib v$ver, please upgrade");
2481 $WARN{$lib} = 2; # never warn again
2489 Carp::croak ("Couldn't load any math lib, not even 'Calc.pm'");
2493 foreach my $class (keys %CALLBACKS)
2495 &{$CALLBACKS{$class}}($CALC);
2498 # Fill $CAN with the results of $CALC->can(...) for emulating lower math lib
2502 for my $method (qw/ signed_and signed_or signed_xor /)
2504 $CAN{$method} = $CALC->can("_$method") ? 1 : 0;
2513 # convert a (ref to) big hex string to BigInt, return undef for error
2516 my $x = Math::BigInt->bzero();
2519 $hs =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
2520 $hs =~ s/([0-9a-fA-F])_([0-9a-fA-F])/$1$2/g;
2522 return $x->bnan() if $hs !~ /^[\-\+]?0x[0-9A-Fa-f]+$/;
2524 my $sign = '+'; $sign = '-' if $hs =~ /^-/;
2526 $hs =~ s/^[+-]//; # strip sign
2527 $x->{value} = $CALC->_from_hex($hs);
2528 $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
2535 # convert a (ref to) big binary string to BigInt, return undef for error
2538 my $x = Math::BigInt->bzero();
2540 $bs =~ s/([01])_([01])/$1$2/g;
2541 $bs =~ s/([01])_([01])/$1$2/g;
2542 return $x->bnan() if $bs !~ /^[+-]?0b[01]+$/;
2544 my $sign = '+'; $sign = '-' if $bs =~ /^\-/;
2545 $bs =~ s/^[+-]//; # strip sign
2547 $x->{value} = $CALC->_from_bin($bs);
2548 $x->{sign} = $sign unless $CALC->_is_zero($x->{value}); # no '-0'
2554 # input: num_str; output: undef for invalid or
2555 # (\$mantissa_sign,\$mantissa_value,\$mantissa_fraction,\$exp_sign,\$exp_value)
2556 # Internal, take apart a string and return the pieces.
2557 # Strip leading/trailing whitespace, leading zeros, underscore and reject
2561 # strip white space at front, also extranous leading zeros
2562 $x =~ s/^\s*([-]?)0*([0-9])/$1$2/g; # will not strip ' .2'
2563 $x =~ s/^\s+//; # but this will
2564 $x =~ s/\s+$//g; # strip white space at end
2566 # shortcut, if nothing to split, return early
2567 if ($x =~ /^[+-]?\d+\z/)
2569 $x =~ s/^([+-])0*([0-9])/$2/; my $sign = $1 || '+';
2570 return (\$sign, \$x, \'', \'', \0);
2573 # invalid starting char?
2574 return if $x !~ /^[+-]?(\.?[0-9]|0b[0-1]|0x[0-9a-fA-F])/;
2576 return __from_hex($x) if $x =~ /^[\-\+]?0x/; # hex string
2577 return __from_bin($x) if $x =~ /^[\-\+]?0b/; # binary string
2579 # strip underscores between digits
2580 $x =~ s/(\d)_(\d)/$1$2/g;
2581 $x =~ s/(\d)_(\d)/$1$2/g; # do twice for 1_2_3
2583 # some possible inputs:
2584 # 2.1234 # 0.12 # 1 # 1E1 # 2.134E1 # 434E-10 # 1.02009E-2
2585 # .2 # 1_2_3.4_5_6 # 1.4E1_2_3 # 1e3 # +.2 # 0e999
2587 my ($m,$e,$last) = split /[Ee]/,$x;
2588 return if defined $last; # last defined => 1e2E3 or others
2589 $e = '0' if !defined $e || $e eq "";
2591 # sign,value for exponent,mantint,mantfrac
2592 my ($es,$ev,$mis,$miv,$mfv);
2594 if ($e =~ /^([+-]?)0*(\d+)$/) # strip leading zeros
2598 return if $m eq '.' || $m eq '';
2599 my ($mi,$mf,$lastf) = split /\./,$m;
2600 return if defined $lastf; # lastf defined => 1.2.3 or others
2601 $mi = '0' if !defined $mi;
2602 $mi .= '0' if $mi =~ /^[\-\+]?$/;
2603 $mf = '0' if !defined $mf || $mf eq '';
2604 if ($mi =~ /^([+-]?)0*(\d+)$/) # strip leading zeros
2606 $mis = $1||'+'; $miv = $2;
2607 return unless ($mf =~ /^(\d*?)0*$/); # strip trailing zeros
2609 # handle the 0e999 case here
2610 $ev = 0 if $miv eq '0' && $mfv eq '';
2611 return (\$mis,\$miv,\$mfv,\$es,\$ev);
2614 return; # NaN, not a number
2617 ##############################################################################
2618 # internal calculation routines (others are in Math::BigInt::Calc etc)
2622 # (BINT or num_str, BINT or num_str) return BINT
2623 # does modify first argument
2627 return $x->bnan() if ($x->{sign} eq $nan) || ($ty->{sign} eq $nan);
2628 my $method = ref($x) . '::bgcd';
2630 $x * $ty / &$method($x,$ty);
2633 ###############################################################################
2634 # this method returns 0 if the object can be modified, or 1 if not.
2635 # We use a fast constant sub() here, to avoid costly calls. Subclasses
2636 # may override it with special code (f.i. Math::BigInt::Constant does so)
2638 sub modify () { 0; }
2645 Math::BigInt - Arbitrary size integer math package
2651 # or make it faster: install (optional) Math::BigInt::GMP
2652 # and always use (it will fall back to pure Perl if the
2653 # GMP library is not installed):
2655 use Math::BigInt lib => 'GMP';
2657 my $str = '1234567890';
2658 my @values = (64,74,18);
2659 my $n = 1; my $sign = '-';
2662 $x = Math::BigInt->new($str); # defaults to 0
2663 $y = $x->copy(); # make a true copy
2664 $nan = Math::BigInt->bnan(); # create a NotANumber
2665 $zero = Math::BigInt->bzero(); # create a +0
2666 $inf = Math::BigInt->binf(); # create a +inf
2667 $inf = Math::BigInt->binf('-'); # create a -inf
2668 $one = Math::BigInt->bone(); # create a +1
2669 $one = Math::BigInt->bone('-'); # create a -1
2671 # Testing (don't modify their arguments)
2672 # (return true if the condition is met, otherwise false)
2674 $x->is_zero(); # if $x is +0
2675 $x->is_nan(); # if $x is NaN
2676 $x->is_one(); # if $x is +1
2677 $x->is_one('-'); # if $x is -1
2678 $x->is_odd(); # if $x is odd
2679 $x->is_even(); # if $x is even
2680 $x->is_pos(); # if $x >= 0
2681 $x->is_neg(); # if $x < 0
2682 $x->is_inf($sign); # if $x is +inf, or -inf (sign is default '+')
2683 $x->is_int(); # if $x is an integer (not a float)
2685 # comparing and digit/sign extration
2686 $x->bcmp($y); # compare numbers (undef,<0,=0,>0)
2687 $x->bacmp($y); # compare absolutely (undef,<0,=0,>0)
2688 $x->sign(); # return the sign, either +,- or NaN
2689 $x->digit($n); # return the nth digit, counting from right
2690 $x->digit(-$n); # return the nth digit, counting from left
2692 # The following all modify their first argument. If you want to preserve
2693 # $x, use $z = $x->copy()->bXXX($y); See under L<CAVEATS> for why this is
2694 # neccessary when mixing $a = $b assigments with non-overloaded math.
2696 $x->bzero(); # set $x to 0
2697 $x->bnan(); # set $x to NaN
2698 $x->bone(); # set $x to +1
2699 $x->bone('-'); # set $x to -1
2700 $x->binf(); # set $x to inf
2701 $x->binf('-'); # set $x to -inf
2703 $x->bneg(); # negation
2704 $x->babs(); # absolute value
2705 $x->bnorm(); # normalize (no-op in BigInt)
2706 $x->bnot(); # two's complement (bit wise not)
2707 $x->binc(); # increment $x by 1
2708 $x->bdec(); # decrement $x by 1
2710 $x->badd($y); # addition (add $y to $x)
2711 $x->bsub($y); # subtraction (subtract $y from $x)
2712 $x->bmul($y); # multiplication (multiply $x by $y)
2713 $x->bdiv($y); # divide, set $x to quotient
2714 # return (quo,rem) or quo if scalar
2716 $x->bmod($y); # modulus (x % y)
2717 $x->bmodpow($exp,$mod); # modular exponentation (($num**$exp) % $mod))
2718 $x->bmodinv($mod); # the inverse of $x in the given modulus $mod
2720 $x->bpow($y); # power of arguments (x ** y)
2721 $x->blsft($y); # left shift
2722 $x->brsft($y); # right shift
2723 $x->blsft($y,$n); # left shift, by base $n (like 10)
2724 $x->brsft($y,$n); # right shift, by base $n (like 10)
2726 $x->band($y); # bitwise and
2727 $x->bior($y); # bitwise inclusive or
2728 $x->bxor($y); # bitwise exclusive or
2729 $x->bnot(); # bitwise not (two's complement)
2731 $x->bsqrt(); # calculate square-root
2732 $x->broot($y); # $y'th root of $x (e.g. $y == 3 => cubic root)
2733 $x->bfac(); # factorial of $x (1*2*3*4*..$x)
2735 $x->round($A,$P,$mode); # round to accuracy or precision using mode $mode
2736 $x->bround($n); # accuracy: preserve $n digits
2737 $x->bfround($n); # round to $nth digit, no-op for BigInts
2739 # The following do not modify their arguments in BigInt (are no-ops),
2740 # but do so in BigFloat:
2742 $x->bfloor(); # return integer less or equal than $x
2743 $x->bceil(); # return integer greater or equal than $x
2745 # The following do not modify their arguments:
2747 # greatest common divisor (no OO style)
2748 my $gcd = Math::BigInt::bgcd(@values);
2749 # lowest common multiplicator (no OO style)
2750 my $lcm = Math::BigInt::blcm(@values);
2752 $x->length(); # return number of digits in number
2753 ($xl,$f) = $x->length(); # length of number and length of fraction part,
2754 # latter is always 0 digits long for BigInts
2756 $x->exponent(); # return exponent as BigInt
2757 $x->mantissa(); # return (signed) mantissa as BigInt
2758 $x->parts(); # return (mantissa,exponent) as BigInt
2759 $x->copy(); # make a true copy of $x (unlike $y = $x;)
2760 $x->as_int(); # return as BigInt (in BigInt: same as copy())
2761 $x->numify(); # return as scalar (might overflow!)
2763 # conversation to string (do not modify their argument)
2764 $x->bstr(); # normalized string (e.g. '3')
2765 $x->bsstr(); # norm. string in scientific notation (e.g. '3E0')
2766 $x->as_hex(); # as signed hexadecimal string with prefixed 0x
2767 $x->as_bin(); # as signed binary string with prefixed 0b
2770 # precision and accuracy (see section about rounding for more)
2771 $x->precision(); # return P of $x (or global, if P of $x undef)
2772 $x->precision($n); # set P of $x to $n
2773 $x->accuracy(); # return A of $x (or global, if A of $x undef)
2774 $x->accuracy($n); # set A $x to $n
2777 Math::BigInt->precision(); # get/set global P for all BigInt objects
2778 Math::BigInt->accuracy(); # get/set global A for all BigInt objects
2779 Math::BigInt->round_mode(); # get/set global round mode, one of
2780 # 'even', 'odd', '+inf', '-inf', 'zero' or 'trunc'
2781 Math::BigInt->config(); # return hash containing configuration
2785 All operators (inlcuding basic math operations) are overloaded if you
2786 declare your big integers as
2788 $i = new Math::BigInt '123_456_789_123_456_789';
2790 Operations with overloaded operators preserve the arguments which is
2791 exactly what you expect.
2797 Input values to these routines may be any string, that looks like a number
2798 and results in an integer, including hexadecimal and binary numbers.
2800 Scalars holding numbers may also be passed, but note that non-integer numbers
2801 may already have lost precision due to the conversation to float. Quote
2802 your input if you want BigInt to see all the digits:
2804 $x = Math::BigInt->new(12345678890123456789); # bad
2805 $x = Math::BigInt->new('12345678901234567890'); # good
2807 You can include one underscore between any two digits.
2809 This means integer values like 1.01E2 or even 1000E-2 are also accepted.
2810 Non-integer values result in NaN.
2812 Currently, Math::BigInt::new() defaults to 0, while Math::BigInt::new('')
2813 results in 'NaN'. This might change in the future, so use always the following
2814 explicit forms to get a zero or NaN:
2816 $zero = Math::BigInt->bzero();
2817 $nan = Math::BigInt->bnan();
2819 C<bnorm()> on a BigInt object is now effectively a no-op, since the numbers
2820 are always stored in normalized form. If passed a string, creates a BigInt
2821 object from the input.
2825 Output values are BigInt objects (normalized), except for the methods which
2826 return a string (see L<SYNOPSIS>).
2828 Some routines (C<is_odd()>, C<is_even()>, C<is_zero()>, C<is_one()>,
2829 C<is_nan()>, etc.) return true or false, while others (C<bcmp()>, C<bacmp()>)
2830 return either undef (if NaN is involved), <0, 0 or >0 and are suited for sort.
2836 Each of the methods below (except config(), accuracy() and precision())
2837 accepts three additional parameters. These arguments C<$A>, C<$P> and C<$R>
2838 are C<accuracy>, C<precision> and C<round_mode>. Please see the section about
2839 L<ACCURACY and PRECISION> for more information.
2845 print Dumper ( Math::BigInt->config() );
2846 print Math::BigInt->config()->{lib},"\n";
2848 Returns a hash containing the configuration, e.g. the version number, lib
2849 loaded etc. The following hash keys are currently filled in with the
2850 appropriate information.
2854 ============================================================
2855 lib Name of the low-level math library
2857 lib_version Version of low-level math library (see 'lib')
2859 class The class name of config() you just called
2861 upgrade To which class math operations might be upgraded
2863 downgrade To which class math operations might be downgraded
2865 precision Global precision
2867 accuracy Global accuracy
2869 round_mode Global round mode
2871 version version number of the class you used
2873 div_scale Fallback acccuracy for div
2875 trap_nan If true, traps creation of NaN via croak()
2877 trap_inf If true, traps creation of +inf/-inf via croak()
2880 The following values can be set by passing C<config()> a reference to a hash:
2883 upgrade downgrade precision accuracy round_mode div_scale
2887 $new_cfg = Math::BigInt->config( { trap_inf => 1, precision => 5 } );
2891 $x->accuracy(5); # local for $x
2892 CLASS->accuracy(5); # global for all members of CLASS
2893 $A = $x->accuracy(); # read out
2894 $A = CLASS->accuracy(); # read out
2896 Set or get the global or local accuracy, aka how many significant digits the
2899 Please see the section about L<ACCURACY AND PRECISION> for further details.
2901 Value must be greater than zero. Pass an undef value to disable it:
2903 $x->accuracy(undef);
2904 Math::BigInt->accuracy(undef);
2906 Returns the current accuracy. For C<$x->accuracy()> it will return either the
2907 local accuracy, or if not defined, the global. This means the return value
2908 represents the accuracy that will be in effect for $x:
2910 $y = Math::BigInt->new(1234567); # unrounded
2911 print Math::BigInt->accuracy(4),"\n"; # set 4, print 4
2912 $x = Math::BigInt->new(123456); # will be automatically rounded
2913 print "$x $y\n"; # '123500 1234567'
2914 print $x->accuracy(),"\n"; # will be 4
2915 print $y->accuracy(),"\n"; # also 4, since global is 4
2916 print Math::BigInt->accuracy(5),"\n"; # set to 5, print 5
2917 print $x->accuracy(),"\n"; # still 4
2918 print $y->accuracy(),"\n"; # 5, since global is 5
2920 Note: Works also for subclasses like Math::BigFloat. Each class has it's own
2921 globals separated from Math::BigInt, but it is possible to subclass
2922 Math::BigInt and make the globals of the subclass aliases to the ones from
2927 $x->precision(-2); # local for $x, round right of the dot
2928 $x->precision(2); # ditto, but round left of the dot
2929 CLASS->accuracy(5); # global for all members of CLASS
2930 CLASS->precision(-5); # ditto
2931 $P = CLASS->precision(); # read out
2932 $P = $x->precision(); # read out
2934 Set or get the global or local precision, aka how many digits the result has
2935 after the dot (or where to round it when passing a positive number). In
2936 Math::BigInt, passing a negative number precision has no effect since no
2937 numbers have digits after the dot.
2939 Please see the section about L<ACCURACY AND PRECISION> for further details.
2941 Value must be greater than zero. Pass an undef value to disable it:
2943 $x->precision(undef);
2944 Math::BigInt->precision(undef);
2946 Returns the current precision. For C<$x->precision()> it will return either the
2947 local precision of $x, or if not defined, the global. This means the return
2948 value represents the accuracy that will be in effect for $x:
2950 $y = Math::BigInt->new(1234567); # unrounded
2951 print Math::BigInt->precision(4),"\n"; # set 4, print 4
2952 $x = Math::BigInt->new(123456); # will be automatically rounded
2954 Note: Works also for subclasses like Math::BigFloat. Each class has it's own
2955 globals separated from Math::BigInt, but it is possible to subclass
2956 Math::BigInt and make the globals of the subclass aliases to the ones from
2963 Shifts $x right by $y in base $n. Default is base 2, used are usually 10 and
2964 2, but others work, too.
2966 Right shifting usually amounts to dividing $x by $n ** $y and truncating the
2970 $x = Math::BigInt->new(10);
2971 $x->brsft(1); # same as $x >> 1: 5
2972 $x = Math::BigInt->new(1234);
2973 $x->brsft(2,10); # result 12
2975 There is one exception, and that is base 2 with negative $x:
2978 $x = Math::BigInt->new(-5);
2981 This will print -3, not -2 (as it would if you divide -5 by 2 and truncate the
2986 $x = Math::BigInt->new($str,$A,$P,$R);
2988 Creates a new BigInt object from a scalar or another BigInt object. The
2989 input is accepted as decimal, hex (with leading '0x') or binary (with leading
2992 See L<Input> for more info on accepted input formats.
2996 $x = Math::BigInt->bnan();
2998 Creates a new BigInt object representing NaN (Not A Number).
2999 If used on an object, it will set it to NaN:
3005 $x = Math::BigInt->bzero();
3007 Creates a new BigInt object representing zero.
3008 If used on an object, it will set it to zero:
3014 $x = Math::BigInt->binf($sign);
3016 Creates a new BigInt object representing infinity. The optional argument is
3017 either '-' or '+', indicating whether you want infinity or minus infinity.
3018 If used on an object, it will set it to infinity:
3025 $x = Math::BigInt->binf($sign);
3027 Creates a new BigInt object representing one. The optional argument is
3028 either '-' or '+', indicating whether you want one or minus one.
3029 If used on an object, it will set it to one:
3034 =head2 is_one()/is_zero()/is_nan()/is_inf()
3037 $x->is_zero(); # true if arg is +0
3038 $x->is_nan(); # true if arg is NaN
3039 $x->is_one(); # true if arg is +1
3040 $x->is_one('-'); # true if arg is -1
3041 $x->is_inf(); # true if +inf
3042 $x->is_inf('-'); # true if -inf (sign is default '+')
3044 These methods all test the BigInt for beeing one specific value and return
3045 true or false depending on the input. These are faster than doing something
3050 =head2 is_pos()/is_neg()
3052 $x->is_pos(); # true if > 0
3053 $x->is_neg(); # true if < 0
3055 The methods return true if the argument is positive or negative, respectively.
3056 C<NaN> is neither positive nor negative, while C<+inf> counts as positive, and
3057 C<-inf> is negative. A C<zero> is neither positive nor negative.
3059 These methods are only testing the sign, and not the value.
3061 C<is_positive()> and C<is_negative()> are aliase to C<is_pos()> and
3062 C<is_neg()>, respectively. C<is_positive()> and C<is_negative()> were
3063 introduced in v1.36, while C<is_pos()> and C<is_neg()> were only introduced
3066 =head2 is_odd()/is_even()/is_int()
3068 $x->is_odd(); # true if odd, false for even
3069 $x->is_even(); # true if even, false for odd
3070 $x->is_int(); # true if $x is an integer
3072 The return true when the argument satisfies the condition. C<NaN>, C<+inf>,
3073 C<-inf> are not integers and are neither odd nor even.
3075 In BigInt, all numbers except C<NaN>, C<+inf> and C<-inf> are integers.
3081 Compares $x with $y and takes the sign into account.
3082 Returns -1, 0, 1 or undef.
3088 Compares $x with $y while ignoring their. Returns -1, 0, 1 or undef.
3094 Return the sign, of $x, meaning either C<+>, C<->, C<-inf>, C<+inf> or NaN.
3096 If you want $x to have a certain sign, use one of the following methods:
3099 $x->babs()->bneg(); # '-'
3101 $x->binf(); # '+inf'
3102 $x->binf('-'); # '-inf'
3106 $x->digit($n); # return the nth digit, counting from right
3108 If C<$n> is negative, returns the digit counting from left.
3114 Negate the number, e.g. change the sign between '+' and '-', or between '+inf'
3115 and '-inf', respectively. Does nothing for NaN or zero.
3121 Set the number to it's absolute value, e.g. change the sign from '-' to '+'
3122 and from '-inf' to '+inf', respectively. Does nothing for NaN or positive
3127 $x->bnorm(); # normalize (no-op)
3133 Two's complement (bit wise not). This is equivalent to
3141 $x->binc(); # increment x by 1
3145 $x->bdec(); # decrement x by 1
3149 $x->badd($y); # addition (add $y to $x)
3153 $x->bsub($y); # subtraction (subtract $y from $x)
3157 $x->bmul($y); # multiplication (multiply $x by $y)
3161 $x->bdiv($y); # divide, set $x to quotient
3162 # return (quo,rem) or quo if scalar
3166 $x->bmod($y); # modulus (x % y)
3170 num->bmodinv($mod); # modular inverse
3172 Returns the inverse of C<$num> in the given modulus C<$mod>. 'C<NaN>' is
3173 returned unless C<$num> is relatively prime to C<$mod>, i.e. unless
3174 C<bgcd($num, $mod)==1>.
3178 $num->bmodpow($exp,$mod); # modular exponentation
3179 # ($num**$exp % $mod)
3181 Returns the value of C<$num> taken to the power C<$exp> in the modulus
3182 C<$mod> using binary exponentation. C<bmodpow> is far superior to
3187 because it is much faster - it reduces internal variables into
3188 the modulus whenever possible, so it operates on smaller numbers.
3190 C<bmodpow> also supports negative exponents.
3192 bmodpow($num, -1, $mod)
3194 is exactly equivalent to
3200 $x->bpow($y); # power of arguments (x ** y)
3204 $x->blsft($y); # left shift
3205 $x->blsft($y,$n); # left shift, in base $n (like 10)
3209 $x->brsft($y); # right shift
3210 $x->brsft($y,$n); # right shift, in base $n (like 10)
3214 $x->band($y); # bitwise and
3218 $x->bior($y); # bitwise inclusive or
3222 $x->bxor($y); # bitwise exclusive or
3226 $x->bnot(); # bitwise not (two's complement)
3230 $x->bsqrt(); # calculate square-root
3234 $x->bfac(); # factorial of $x (1*2*3*4*..$x)
3238 $x->round($A,$P,$round_mode);
3240 Round $x to accuracy C<$A> or precision C<$P> using the round mode
3245 $x->bround($N); # accuracy: preserve $N digits
3249 $x->bfround($N); # round to $Nth digit, no-op for BigInts
3255 Set $x to the integer less or equal than $x. This is a no-op in BigInt, but
3256 does change $x in BigFloat.
3262 Set $x to the integer greater or equal than $x. This is a no-op in BigInt, but
3263 does change $x in BigFloat.
3267 bgcd(@values); # greatest common divisor (no OO style)
3271 blcm(@values); # lowest common multiplicator (no OO style)
3276 ($xl,$fl) = $x->length();
3278 Returns the number of digits in the decimal representation of the number.
3279 In list context, returns the length of the integer and fraction part. For
3280 BigInt's, the length of the fraction part will always be 0.
3286 Return the exponent of $x as BigInt.
3292 Return the signed mantissa of $x as BigInt.
3296 $x->parts(); # return (mantissa,exponent) as BigInt
3300 $x->copy(); # make a true copy of $x (unlike $y = $x;)
3306 Returns $x as a BigInt (truncated towards zero). In BigInt this is the same as
3309 C<as_number()> is an alias to this method. C<as_number> was introduced in
3310 v1.22, while C<as_int()> was only introduced in v1.68.
3316 Returns a normalized string represantation of C<$x>.
3320 $x->bsstr(); # normalized string in scientific notation
3324 $x->as_hex(); # as signed hexadecimal string with prefixed 0x
3328 $x->as_bin(); # as signed binary string with prefixed 0b
3330 =head1 ACCURACY and PRECISION
3332 Since version v1.33, Math::BigInt and Math::BigFloat have full support for
3333 accuracy and precision based rounding, both automatically after every
3334 operation, as well as manually.
3336 This section describes the accuracy/precision handling in Math::Big* as it
3337 used to be and as it is now, complete with an explanation of all terms and
3340 Not yet implemented things (but with correct description) are marked with '!',
3341 things that need to be answered are marked with '?'.
3343 In the next paragraph follows a short description of terms used here (because
3344 these may differ from terms used by others people or documentation).
3346 During the rest of this document, the shortcuts A (for accuracy), P (for
3347 precision), F (fallback) and R (rounding mode) will be used.
3351 A fixed number of digits before (positive) or after (negative)
3352 the decimal point. For example, 123.45 has a precision of -2. 0 means an
3353 integer like 123 (or 120). A precision of 2 means two digits to the left
3354 of the decimal point are zero, so 123 with P = 1 becomes 120. Note that
3355 numbers with zeros before the decimal point may have different precisions,
3356 because 1200 can have p = 0, 1 or 2 (depending on what the inital value
3357 was). It could also have p < 0, when the digits after the decimal point
3360 The string output (of floating point numbers) will be padded with zeros:
3362 Initial value P A Result String
3363 ------------------------------------------------------------
3364 1234.01 -3 1000 1000
3367 1234.001 1 1234 1234.0
3369 1234.01 2 1234.01 1234.01
3370 1234.01 5 1234.01 1234.01000
3372 For BigInts, no padding occurs.
3376 Number of significant digits. Leading zeros are not counted. A
3377 number may have an accuracy greater than the non-zero digits
3378 when there are zeros in it or trailing zeros. For example, 123.456 has
3379 A of 6, 10203 has 5, 123.0506 has 7, 123.450000 has 8 and 0.000123 has 3.
3381 The string output (of floating point numbers) will be padded with zeros:
3383 Initial value P A Result String
3384 ------------------------------------------------------------
3386 1234.01 6 1234.01 1234.01
3387 1234.1 8 1234.1 1234.1000
3389 For BigInts, no padding occurs.
3393 When both A and P are undefined, this is used as a fallback accuracy when
3396 =head2 Rounding mode R
3398 When rounding a number, different 'styles' or 'kinds'
3399 of rounding are possible. (Note that random rounding, as in
3400 Math::Round, is not implemented.)
3406 truncation invariably removes all digits following the
3407 rounding place, replacing them with zeros. Thus, 987.65 rounded
3408 to tens (P=1) becomes 980, and rounded to the fourth sigdig
3409 becomes 987.6 (A=4). 123.456 rounded to the second place after the
3410 decimal point (P=-2) becomes 123.46.
3412 All other implemented styles of rounding attempt to round to the
3413 "nearest digit." If the digit D immediately to the right of the
3414 rounding place (skipping the decimal point) is greater than 5, the
3415 number is incremented at the rounding place (possibly causing a
3416 cascade of incrementation): e.g. when rounding to units, 0.9 rounds
3417 to 1, and -19.9 rounds to -20. If D < 5, the number is similarly
3418 truncated at the rounding place: e.g. when rounding to units, 0.4
3419 rounds to 0, and -19.4 rounds to -19.
3421 However the results of other styles of rounding differ if the
3422 digit immediately to the right of the rounding place (skipping the
3423 decimal point) is 5 and if there are no digits, or no digits other
3424 than 0, after that 5. In such cases:
3428 rounds the digit at the rounding place to 0, 2, 4, 6, or 8
3429 if it is not already. E.g., when rounding to the first sigdig, 0.45
3430 becomes 0.4, -0.55 becomes -0.6, but 0.4501 becomes 0.5.
3434 rounds the digit at the rounding place to 1, 3, 5, 7, or 9 if
3435 it is not already. E.g., when rounding to the first sigdig, 0.45
3436 becomes 0.5, -0.55 becomes -0.5, but 0.5501 becomes 0.6.
3440 round to plus infinity, i.e. always round up. E.g., when
3441 rounding to the first sigdig, 0.45 becomes 0.5, -0.55 becomes -0.5,
3442 and 0.4501 also becomes 0.5.
3446 round to minus infinity, i.e. always round down. E.g., when
3447 rounding to the first sigdig, 0.45 becomes 0.4, -0.55 becomes -0.6,
3448 but 0.4501 becomes 0.5.
3452 round to zero, i.e. positive numbers down, negative ones up.
3453 E.g., when rounding to the first sigdig, 0.45 becomes 0.4, -0.55
3454 becomes -0.5, but 0.4501 becomes 0.5.
3458 The handling of A & P in MBI/MBF (the old core code shipped with Perl
3459 versions <= 5.7.2) is like this:
3465 * ffround($p) is able to round to $p number of digits after the decimal
3467 * otherwise P is unused
3469 =item Accuracy (significant digits)
3471 * fround($a) rounds to $a significant digits
3472 * only fdiv() and fsqrt() take A as (optional) paramater
3473 + other operations simply create the same number (fneg etc), or more (fmul)
3475 + rounding/truncating is only done when explicitly calling one of fround
3476 or ffround, and never for BigInt (not implemented)
3477 * fsqrt() simply hands its accuracy argument over to fdiv.
3478 * the documentation and the comment in the code indicate two different ways
3479 on how fdiv() determines the maximum number of digits it should calculate,
3480 and the actual code does yet another thing
3482 max($Math::BigFloat::div_scale,length(dividend)+length(divisor))
3484 result has at most max(scale, length(dividend), length(divisor)) digits
3486 scale = max(scale, length(dividend)-1,length(divisor)-1);
3487 scale += length(divisior) - length(dividend);
3488 So for lx = 3, ly = 9, scale = 10, scale will actually be 16 (10+9-3).
3489 Actually, the 'difference' added to the scale is calculated from the
3490 number of "significant digits" in dividend and divisor, which is derived
3491 by looking at the length of the mantissa. Which is wrong, since it includes
3492 the + sign (oops) and actually gets 2 for '+100' and 4 for '+101'. Oops
3493 again. Thus 124/3 with div_scale=1 will get you '41.3' based on the strange
3494 assumption that 124 has 3 significant digits, while 120/7 will get you
3495 '17', not '17.1' since 120 is thought to have 2 significant digits.
3496 The rounding after the division then uses the remainder and $y to determine
3497 wether it must round up or down.
3498 ? I have no idea which is the right way. That's why I used a slightly more
3499 ? simple scheme and tweaked the few failing testcases to match it.
3503 This is how it works now:
3507 =item Setting/Accessing
3509 * You can set the A global via C<< Math::BigInt->accuracy() >> or
3510 C<< Math::BigFloat->accuracy() >> or whatever class you are using.
3511 * You can also set P globally by using C<< Math::SomeClass->precision() >>
3513 * Globals are classwide, and not inherited by subclasses.
3514 * to undefine A, use C<< Math::SomeCLass->accuracy(undef); >>
3515 * to undefine P, use C<< Math::SomeClass->precision(undef); >>
3516 * Setting C<< Math::SomeClass->accuracy() >> clears automatically
3517 C<< Math::SomeClass->precision() >>, and vice versa.
3518 * To be valid, A must be > 0, P can have any value.
3519 * If P is negative, this means round to the P'th place to the right of the
3520 decimal point; positive values mean to the left of the decimal point.
3521 P of 0 means round to integer.
3522 * to find out the current global A, use C<< Math::SomeClass->accuracy() >>
3523 * to find out the current global P, use C<< Math::SomeClass->precision() >>
3524 * use C<< $x->accuracy() >> respective C<< $x->precision() >> for the local
3525 setting of C<< $x >>.
3526 * Please note that C<< $x->accuracy() >> respecive C<< $x->precision() >>
3527 return eventually defined global A or P, when C<< $x >>'s A or P is not
3530 =item Creating numbers
3532 * When you create a number, you can give it's desired A or P via:
3533 $x = Math::BigInt->new($number,$A,$P);
3534 * Only one of A or P can be defined, otherwise the result is NaN
3535 * If no A or P is give ($x = Math::BigInt->new($number) form), then the
3536 globals (if set) will be used. Thus changing the global defaults later on
3537 will not change the A or P of previously created numbers (i.e., A and P of
3538 $x will be what was in effect when $x was created)
3539 * If given undef for A and P, B<no> rounding will occur, and the globals will
3540 B<not> be used. This is used by subclasses to create numbers without
3541 suffering rounding in the parent. Thus a subclass is able to have it's own
3542 globals enforced upon creation of a number by using
3543 C<< $x = Math::BigInt->new($number,undef,undef) >>:
3545 use Math::BigInt::SomeSubclass;
3548 Math::BigInt->accuracy(2);
3549 Math::BigInt::SomeSubClass->accuracy(3);
3550 $x = Math::BigInt::SomeSubClass->new(1234);
3552 $x is now 1230, and not 1200. A subclass might choose to implement
3553 this otherwise, e.g. falling back to the parent's A and P.
3557 * If A or P are enabled/defined, they are used to round the result of each
3558 operation according to the rules below
3559 * Negative P is ignored in Math::BigInt, since BigInts never have digits
3560 after the decimal point
3561 * Math::BigFloat uses Math::BigInt internally, but setting A or P inside
3562 Math::BigInt as globals does not tamper with the parts of a BigFloat.
3563 A flag is used to mark all Math::BigFloat numbers as 'never round'.
3567 * It only makes sense that a number has only one of A or P at a time.
3568 If you set either A or P on one object, or globally, the other one will
3569 be automatically cleared.
3570 * If two objects are involved in an operation, and one of them has A in
3571 effect, and the other P, this results in an error (NaN).
3572 * A takes precendence over P (Hint: A comes before P).
3573 If neither of them is defined, nothing is used, i.e. the result will have
3574 as many digits as it can (with an exception for fdiv/fsqrt) and will not
3576 * There is another setting for fdiv() (and thus for fsqrt()). If neither of
3577 A or P is defined, fdiv() will use a fallback (F) of $div_scale digits.
3578 If either the dividend's or the divisor's mantissa has more digits than
3579 the value of F, the higher value will be used instead of F.
3580 This is to limit the digits (A) of the result (just consider what would
3581 happen with unlimited A and P in the case of 1/3 :-)
3582 * fdiv will calculate (at least) 4 more digits than required (determined by
3583 A, P or F), and, if F is not used, round the result
3584 (this will still fail in the case of a result like 0.12345000000001 with A
3585 or P of 5, but this can not be helped - or can it?)
3586 * Thus you can have the math done by on Math::Big* class in two modi:
3587 + never round (this is the default):
3588 This is done by setting A and P to undef. No math operation
3589 will round the result, with fdiv() and fsqrt() as exceptions to guard
3590 against overflows. You must explicitely call bround(), bfround() or
3591 round() (the latter with parameters).
3592 Note: Once you have rounded a number, the settings will 'stick' on it
3593 and 'infect' all other numbers engaged in math operations with it, since
3594 local settings have the highest precedence. So, to get SaferRound[tm],
3595 use a copy() before rounding like this:
3597 $x = Math::BigFloat->new(12.34);
3598 $y = Math::BigFloat->new(98.76);
3599 $z = $x * $y; # 1218.6984
3600 print $x->copy()->fround(3); # 12.3 (but A is now 3!)
3601 $z = $x * $y; # still 1218.6984, without
3602 # copy would have been 1210!
3604 + round after each op:
3605 After each single operation (except for testing like is_zero()), the
3606 method round() is called and the result is rounded appropriately. By
3607 setting proper values for A and P, you can have all-the-same-A or
3608 all-the-same-P modes. For example, Math::Currency might set A to undef,
3609 and P to -2, globally.
3611 ?Maybe an extra option that forbids local A & P settings would be in order,
3612 ?so that intermediate rounding does not 'poison' further math?
3614 =item Overriding globals
3616 * you will be able to give A, P and R as an argument to all the calculation
3617 routines; the second parameter is A, the third one is P, and the fourth is
3618 R (shift right by one for binary operations like badd). P is used only if
3619 the first parameter (A) is undefined. These three parameters override the
3620 globals in the order detailed as follows, i.e. the first defined value
3622 (local: per object, global: global default, parameter: argument to sub)
3625 + local A (if defined on both of the operands: smaller one is taken)
3626 + local P (if defined on both of the operands: bigger one is taken)
3630 * fsqrt() will hand its arguments to fdiv(), as it used to, only now for two
3631 arguments (A and P) instead of one
3633 =item Local settings
3635 * You can set A or P locally by using C<< $x->accuracy() >> or
3636 C<< $x->precision() >>
3637 and thus force different A and P for different objects/numbers.
3638 * Setting A or P this way immediately rounds $x to the new value.
3639 * C<< $x->accuracy() >> clears C<< $x->precision() >>, and vice versa.
3643 * the rounding routines will use the respective global or local settings.
3644 fround()/bround() is for accuracy rounding, while ffround()/bfround()
3646 * the two rounding functions take as the second parameter one of the
3647 following rounding modes (R):
3648 'even', 'odd', '+inf', '-inf', 'zero', 'trunc'
3649 * you can set/get the global R by using C<< Math::SomeClass->round_mode() >>
3650 or by setting C<< $Math::SomeClass::round_mode >>
3651 * after each operation, C<< $result->round() >> is called, and the result may
3652 eventually be rounded (that is, if A or P were set either locally,
3653 globally or as parameter to the operation)
3654 * to manually round a number, call C<< $x->round($A,$P,$round_mode); >>
3655 this will round the number by using the appropriate rounding function
3656 and then normalize it.
3657 * rounding modifies the local settings of the number:
3659 $x = Math::BigFloat->new(123.456);
3663 Here 4 takes precedence over 5, so 123.5 is the result and $x->accuracy()
3664 will be 4 from now on.
3666 =item Default values
3675 * The defaults are set up so that the new code gives the same results as
3676 the old code (except in a few cases on fdiv):
3677 + Both A and P are undefined and thus will not be used for rounding
3678 after each operation.
3679 + round() is thus a no-op, unless given extra parameters A and P
3683 =head1 Infinity and Not a Number
3685 While BigInt has extensive handling of inf and NaN, certain quirks remain.
3691 These perl routines currently (as of Perl v.5.8.6) cannot handle passed
3694 te@linux:~> perl -wle 'print 2 ** 3333'
3696 te@linux:~> perl -wle 'print 2 ** 3333 == 2 ** 3333'
3698 te@linux:~> perl -wle 'print oct(2 ** 3333)'
3700 te@linux:~> perl -wle 'print hex(2 ** 3333)'
3701 Illegal hexadecimal digit 'i' ignored at -e line 1.
3704 The same problems occur if you pass them Math::BigInt->binf() objects. Since
3705 overloading these routines is not possible, this cannot be fixed from BigInt.
3707 =item ==, !=, <, >, <=, >= with NaNs
3709 BigInt's bcmp() routine currently returns undef to signal that a NaN was
3710 involved in a comparisation. However, the overload code turns that into
3711 either 1 or '' and thus operations like C<< NaN != NaN >> might return
3716 C<< log(-inf) >> is highly weird. Since log(-x)=pi*i+log(x), then
3717 log(-inf)=pi*i+inf. However, since the imaginary part is finite, the real
3718 infinity "overshadows" it, so the number might as well just be infinity.
3719 However, the result is a complex number, and since BigInt/BigFloat can only
3720 have real numbers as results, the result is NaN.
3722 =item exp(), cos(), sin(), atan2()
3724 These all might have problems handling infinity right.
3730 The actual numbers are stored as unsigned big integers (with seperate sign).
3732 You should neither care about nor depend on the internal representation; it
3733 might change without notice. Use B<ONLY> method calls like C<< $x->sign(); >>
3734 instead relying on the internal representation.
3738 Math with the numbers is done (by default) by a module called
3739 C<Math::BigInt::Calc>. This is equivalent to saying:
3741 use Math::BigInt lib => 'Calc';
3743 You can change this by using:
3745 use Math::BigInt lib => 'BitVect';
3747 The following would first try to find Math::BigInt::Foo, then
3748 Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
3750 use Math::BigInt lib => 'Foo,Math::BigInt::Bar';
3752 Since Math::BigInt::GMP is in almost all cases faster than Calc (especially in
3753 math involving really big numbers, where it is B<much> faster), and there is
3754 no penalty if Math::BigInt::GMP is not installed, it is a good idea to always
3757 use Math::BigInt lib => 'GMP';
3759 Different low-level libraries use different formats to store the
3760 numbers. You should B<NOT> depend on the number having a specific format
3763 See the respective math library module documentation for further details.
3767 The sign is either '+', '-', 'NaN', '+inf' or '-inf'.
3769 A sign of 'NaN' is used to represent the result when input arguments are not
3770 numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively
3771 minus infinity. You will get '+inf' when dividing a positive number by 0, and
3772 '-inf' when dividing any negative number by 0.
3774 =head2 mantissa(), exponent() and parts()
3776 C<mantissa()> and C<exponent()> return the said parts of the BigInt such
3779 $m = $x->mantissa();
3780 $e = $x->exponent();
3781 $y = $m * ( 10 ** $e );
3782 print "ok\n" if $x == $y;
3784 C<< ($m,$e) = $x->parts() >> is just a shortcut that gives you both of them
3785 in one go. Both the returned mantissa and exponent have a sign.
3787 Currently, for BigInts C<$e> is always 0, except for NaN, +inf and -inf,
3788 where it is C<NaN>; and for C<$x == 0>, where it is C<1> (to be compatible
3789 with Math::BigFloat's internal representation of a zero as C<0E1>).
3791 C<$m> is currently just a copy of the original number. The relation between
3792 C<$e> and C<$m> will stay always the same, though their real values might
3799 sub bint { Math::BigInt->new(shift); }
3801 $x = Math::BigInt->bstr("1234") # string "1234"
3802 $x = "$x"; # same as bstr()
3803 $x = Math::BigInt->bneg("1234"); # BigInt "-1234"
3804 $x = Math::BigInt->babs("-12345"); # BigInt "12345"
3805 $x = Math::BigInt->bnorm("-0 00"); # BigInt "0"
3806 $x = bint(1) + bint(2); # BigInt "3"
3807 $x = bint(1) + "2"; # ditto (auto-BigIntify of "2")
3808 $x = bint(1); # BigInt "1"
3809 $x = $x + 5 / 2; # BigInt "3"
3810 $x = $x ** 3; # BigInt "27"
3811 $x *= 2; # BigInt "54"
3812 $x = Math::BigInt->new(0); # BigInt "0"
3814 $x = Math::BigInt->badd(4,5) # BigInt "9"
3815 print $x->bsstr(); # 9e+0
3817 Examples for rounding:
3822 $x = Math::BigFloat->new(123.4567);
3823 $y = Math::BigFloat->new(123.456789);
3824 Math::BigFloat->accuracy(4); # no more A than 4
3826 ok ($x->copy()->fround(),123.4); # even rounding
3827 print $x->copy()->fround(),"\n"; # 123.4
3828 Math::BigFloat->round_mode('odd'); # round to odd
3829 print $x->copy()->fround(),"\n"; # 123.5
3830 Math::BigFloat->accuracy(5); # no more A than 5
3831 Math::BigFloat->round_mode('odd'); # round to odd
3832 print $x->copy()->fround(),"\n"; # 123.46
3833 $y = $x->copy()->fround(4),"\n"; # A = 4: 123.4
3834 print "$y, ",$y->accuracy(),"\n"; # 123.4, 4
3836 Math::BigFloat->accuracy(undef); # A not important now
3837 Math::BigFloat->precision(2); # P important
3838 print $x->copy()->bnorm(),"\n"; # 123.46
3839 print $x->copy()->fround(),"\n"; # 123.46
3841 Examples for converting:
3843 my $x = Math::BigInt->new('0b1'.'01' x 123);
3844 print "bin: ",$x->as_bin()," hex:",$x->as_hex()," dec: ",$x,"\n";
3846 =head1 Autocreating constants
3848 After C<use Math::BigInt ':constant'> all the B<integer> decimal, hexadecimal
3849 and binary constants in the given scope are converted to C<Math::BigInt>.
3850 This conversion happens at compile time.
3854 perl -MMath::BigInt=:constant -e 'print 2**100,"\n"'
3856 prints the integer value of C<2**100>. Note that without conversion of
3857 constants the expression 2**100 will be calculated as perl scalar.
3859 Please note that strings and floating point constants are not affected,
3862 use Math::BigInt qw/:constant/;
3864 $x = 1234567890123456789012345678901234567890
3865 + 123456789123456789;
3866 $y = '1234567890123456789012345678901234567890'
3867 + '123456789123456789';
3869 do not work. You need an explicit Math::BigInt->new() around one of the
3870 operands. You should also quote large constants to protect loss of precision:
3874 $x = Math::BigInt->new('1234567889123456789123456789123456789');
3876 Without the quotes Perl would convert the large number to a floating point
3877 constant at compile time and then hand the result to BigInt, which results in
3878 an truncated result or a NaN.
3880 This also applies to integers that look like floating point constants:
3882 use Math::BigInt ':constant';
3884 print ref(123e2),"\n";
3885 print ref(123.2e2),"\n";
3887 will print nothing but newlines. Use either L<bignum> or L<Math::BigFloat>
3888 to get this to work.
3892 Using the form $x += $y; etc over $x = $x + $y is faster, since a copy of $x
3893 must be made in the second case. For long numbers, the copy can eat up to 20%
3894 of the work (in the case of addition/subtraction, less for
3895 multiplication/division). If $y is very small compared to $x, the form
3896 $x += $y is MUCH faster than $x = $x + $y since making the copy of $x takes
3897 more time then the actual addition.
3899 With a technique called copy-on-write, the cost of copying with overload could
3900 be minimized or even completely avoided. A test implementation of COW did show
3901 performance gains for overloaded math, but introduced a performance loss due
3902 to a constant overhead for all other operatons. So Math::BigInt does currently
3905 The rewritten version of this module (vs. v0.01) is slower on certain
3906 operations, like C<new()>, C<bstr()> and C<numify()>. The reason are that it
3907 does now more work and handles much more cases. The time spent in these
3908 operations is usually gained in the other math operations so that code on
3909 the average should get (much) faster. If they don't, please contact the author.
3911 Some operations may be slower for small numbers, but are significantly faster
3912 for big numbers. Other operations are now constant (O(1), like C<bneg()>,
3913 C<babs()> etc), instead of O(N) and thus nearly always take much less time.
3914 These optimizations were done on purpose.
3916 If you find the Calc module to slow, try to install any of the replacement
3917 modules and see if they help you.
3919 =head2 Alternative math libraries
3921 You can use an alternative library to drive Math::BigInt via:
3923 use Math::BigInt lib => 'Module';
3925 See L<MATH LIBRARY> for more information.
3927 For more benchmark results see L<http://bloodgate.com/perl/benchmarks.html>.
3931 =head1 Subclassing Math::BigInt
3933 The basic design of Math::BigInt allows simple subclasses with very little
3934 work, as long as a few simple rules are followed:
3940 The public API must remain consistent, i.e. if a sub-class is overloading
3941 addition, the sub-class must use the same name, in this case badd(). The
3942 reason for this is that Math::BigInt is optimized to call the object methods
3947 The private object hash keys like C<$x->{sign}> may not be changed, but
3948 additional keys can be added, like C<$x->{_custom}>.
3952 Accessor functions are available for all existing object hash keys and should
3953 be used instead of directly accessing the internal hash keys. The reason for
3954 this is that Math::BigInt itself has a pluggable interface which permits it
3955 to support different storage methods.
3959 More complex sub-classes may have to replicate more of the logic internal of
3960 Math::BigInt if they need to change more basic behaviors. A subclass that
3961 needs to merely change the output only needs to overload C<bstr()>.
3963 All other object methods and overloaded functions can be directly inherited
3964 from the parent class.
3966 At the very minimum, any subclass will need to provide it's own C<new()> and can
3967 store additional hash keys in the object. There are also some package globals
3968 that must be defined, e.g.:
3972 $precision = -2; # round to 2 decimal places
3973 $round_mode = 'even';
3976 Additionally, you might want to provide the following two globals to allow
3977 auto-upgrading and auto-downgrading to work correctly:
3982 This allows Math::BigInt to correctly retrieve package globals from the
3983 subclass, like C<$SubClass::precision>. See t/Math/BigInt/Subclass.pm or
3984 t/Math/BigFloat/SubClass.pm completely functional subclass examples.
3990 in your subclass to automatically inherit the overloading from the parent. If
3991 you like, you can change part of the overloading, look at Math::String for an
3996 When used like this:
3998 use Math::BigInt upgrade => 'Foo::Bar';
4000 certain operations will 'upgrade' their calculation and thus the result to
4001 the class Foo::Bar. Usually this is used in conjunction with Math::BigFloat:
4003 use Math::BigInt upgrade => 'Math::BigFloat';
4005 As a shortcut, you can use the module C<bignum>:
4009 Also good for oneliners:
4011 perl -Mbignum -le 'print 2 ** 255'
4013 This makes it possible to mix arguments of different classes (as in 2.5 + 2)
4014 as well es preserve accuracy (as in sqrt(3)).
4016 Beware: This feature is not fully implemented yet.
4020 The following methods upgrade themselves unconditionally; that is if upgrade
4021 is in effect, they will always hand up their work:
4033 Beware: This list is not complete.
4035 All other methods upgrade themselves only when one (or all) of their
4036 arguments are of the class mentioned in $upgrade (This might change in later
4037 versions to a more sophisticated scheme):
4043 =item broot() does not work
4045 The broot() function in BigInt may only work for small values. This will be
4046 fixed in a later version.
4048 =item Out of Memory!
4050 Under Perl prior to 5.6.0 having an C<use Math::BigInt ':constant';> and
4051 C<eval()> in your code will crash with "Out of memory". This is probably an
4052 overload/exporter bug. You can workaround by not having C<eval()>
4053 and ':constant' at the same time or upgrade your Perl to a newer version.
4055 =item Fails to load Calc on Perl prior 5.6.0
4057 Since eval(' use ...') can not be used in conjunction with ':constant', BigInt
4058 will fall back to eval { require ... } when loading the math lib on Perls
4059 prior to 5.6.0. This simple replaces '::' with '/' and thus might fail on
4060 filesystems using a different seperator.
4066 Some things might not work as you expect them. Below is documented what is
4067 known to be troublesome:
4071 =item bstr(), bsstr() and 'cmp'
4073 Both C<bstr()> and C<bsstr()> as well as automated stringify via overload now
4074 drop the leading '+'. The old code would return '+3', the new returns '3'.
4075 This is to be consistent with Perl and to make C<cmp> (especially with
4076 overloading) to work as you expect. It also solves problems with C<Test.pm>,
4077 because it's C<ok()> uses 'eq' internally.
4079 Mark Biggar said, when asked about to drop the '+' altogether, or make only
4082 I agree (with the first alternative), don't add the '+' on positive
4083 numbers. It's not as important anymore with the new internal
4084 form for numbers. It made doing things like abs and neg easier,
4085 but those have to be done differently now anyway.
4087 So, the following examples will now work all as expected:
4090 BEGIN { plan tests => 1 }
4093 my $x = new Math::BigInt 3*3;
4094 my $y = new Math::BigInt 3*3;
4097 print "$x eq 9" if $x eq $y;
4098 print "$x eq 9" if $x eq '9';
4099 print "$x eq 9" if $x eq 3*3;
4101 Additionally, the following still works:
4103 print "$x == 9" if $x == $y;
4104 print "$x == 9" if $x == 9;
4105 print "$x == 9" if $x == 3*3;
4107 There is now a C<bsstr()> method to get the string in scientific notation aka
4108 C<1e+2> instead of C<100>. Be advised that overloaded 'eq' always uses bstr()
4109 for comparisation, but Perl will represent some numbers as 100 and others
4110 as 1e+308. If in doubt, convert both arguments to Math::BigInt before
4111 comparing them as strings:
4114 BEGIN { plan tests => 3 }
4117 $x = Math::BigInt->new('1e56'); $y = 1e56;
4118 ok ($x,$y); # will fail
4119 ok ($x->bsstr(),$y); # okay
4120 $y = Math::BigInt->new($y);
4123 Alternatively, simple use C<< <=> >> for comparisations, this will get it
4124 always right. There is not yet a way to get a number automatically represented
4125 as a string that matches exactly the way Perl represents it.
4127 See also the section about L<Infinity and Not a Number> for problems in
4132 C<int()> will return (at least for Perl v5.7.1 and up) another BigInt, not a
4135 $x = Math::BigInt->new(123);
4136 $y = int($x); # BigInt 123
4137 $x = Math::BigFloat->new(123.45);
4138 $y = int($x); # BigInt 123
4140 In all Perl versions you can use C<as_number()> or C<as_int> for the same
4143 $x = Math::BigFloat->new(123.45);
4144 $y = $x->as_number(); # BigInt 123
4145 $y = $x->as_int(); # ditto
4147 This also works for other subclasses, like Math::String.
4149 It is yet unlcear whether overloaded int() should return a scalar or a BigInt.
4151 If you want a real Perl scalar, use C<numify()>:
4153 $y = $x->numify(); # 123 as scalar
4155 This is seldom necessary, though, because this is done automatically, like
4156 when you access an array:
4158 $z = $array[$x]; # does work automatically
4162 The following will probably not do what you expect:
4164 $c = Math::BigInt->new(123);
4165 print $c->length(),"\n"; # prints 30
4167 It prints both the number of digits in the number and in the fraction part
4168 since print calls C<length()> in list context. Use something like:
4170 print scalar $c->length(),"\n"; # prints 3
4174 The following will probably not do what you expect:
4176 print $c->bdiv(10000),"\n";
4178 It prints both quotient and remainder since print calls C<bdiv()> in list
4179 context. Also, C<bdiv()> will modify $c, so be carefull. You probably want
4182 print $c / 10000,"\n";
4183 print scalar $c->bdiv(10000),"\n"; # or if you want to modify $c
4187 The quotient is always the greatest integer less than or equal to the
4188 real-valued quotient of the two operands, and the remainder (when it is
4189 nonzero) always has the same sign as the second operand; so, for
4199 As a consequence, the behavior of the operator % agrees with the
4200 behavior of Perl's built-in % operator (as documented in the perlop
4201 manpage), and the equation
4203 $x == ($x / $y) * $y + ($x % $y)
4205 holds true for any $x and $y, which justifies calling the two return
4206 values of bdiv() the quotient and remainder. The only exception to this rule
4207 are when $y == 0 and $x is negative, then the remainder will also be
4208 negative. See below under "infinity handling" for the reasoning behing this.
4210 Perl's 'use integer;' changes the behaviour of % and / for scalars, but will
4211 not change BigInt's way to do things. This is because under 'use integer' Perl
4212 will do what the underlying C thinks is right and this is different for each
4213 system. If you need BigInt's behaving exactly like Perl's 'use integer', bug
4214 the author to implement it ;)
4216 =item infinity handling
4218 Here are some examples that explain the reasons why certain results occur while
4221 The following table shows the result of the division and the remainder, so that
4222 the equation above holds true. Some "ordinary" cases are strewn in to show more
4223 clearly the reasoning:
4225 A / B = C, R so that C * B + R = A
4226 =========================================================
4227 5 / 8 = 0, 5 0 * 8 + 5 = 5
4228 0 / 8 = 0, 0 0 * 8 + 0 = 0
4229 0 / inf = 0, 0 0 * inf + 0 = 0
4230 0 /-inf = 0, 0 0 * -inf + 0 = 0
4231 5 / inf = 0, 5 0 * inf + 5 = 5
4232 5 /-inf = 0, 5 0 * -inf + 5 = 5
4233 -5/ inf = 0, -5 0 * inf + -5 = -5
4234 -5/-inf = 0, -5 0 * -inf + -5 = -5
4235 inf/ 5 = inf, 0 inf * 5 + 0 = inf
4236 -inf/ 5 = -inf, 0 -inf * 5 + 0 = -inf
4237 inf/ -5 = -inf, 0 -inf * -5 + 0 = inf
4238 -inf/ -5 = inf, 0 inf * -5 + 0 = -inf
4239 5/ 5 = 1, 0 1 * 5 + 0 = 5
4240 -5/ -5 = 1, 0 1 * -5 + 0 = -5
4241 inf/ inf = 1, 0 1 * inf + 0 = inf
4242 -inf/-inf = 1, 0 1 * -inf + 0 = -inf
4243 inf/-inf = -1, 0 -1 * -inf + 0 = inf
4244 -inf/ inf = -1, 0 1 * -inf + 0 = -inf
4245 8/ 0 = inf, 8 inf * 0 + 8 = 8
4246 inf/ 0 = inf, inf inf * 0 + inf = inf
4249 These cases below violate the "remainder has the sign of the second of the two
4250 arguments", since they wouldn't match up otherwise.
4252 A / B = C, R so that C * B + R = A
4253 ========================================================
4254 -inf/ 0 = -inf, -inf -inf * 0 + inf = -inf
4255 -8/ 0 = -inf, -8 -inf * 0 + 8 = -8
4257 =item Modifying and =
4261 $x = Math::BigFloat->new(5);
4264 It will not do what you think, e.g. making a copy of $x. Instead it just makes
4265 a second reference to the B<same> object and stores it in $y. Thus anything
4266 that modifies $x (except overloaded operators) will modify $y, and vice versa.
4267 Or in other words, C<=> is only safe if you modify your BigInts only via
4268 overloaded math. As soon as you use a method call it breaks:
4271 print "$x, $y\n"; # prints '10, 10'
4273 If you want a true copy of $x, use:
4277 You can also chain the calls like this, this will make first a copy and then
4280 $y = $x->copy()->bmul(2);
4282 See also the documentation for overload.pm regarding C<=>.
4286 C<bpow()> (and the rounding functions) now modifies the first argument and
4287 returns it, unlike the old code which left it alone and only returned the
4288 result. This is to be consistent with C<badd()> etc. The first three will
4289 modify $x, the last one won't:
4291 print bpow($x,$i),"\n"; # modify $x
4292 print $x->bpow($i),"\n"; # ditto
4293 print $x **= $i,"\n"; # the same
4294 print $x ** $i,"\n"; # leave $x alone
4296 The form C<$x **= $y> is faster than C<$x = $x ** $y;>, though.
4298 =item Overloading -$x
4308 since overload calls C<sub($x,0,1);> instead of C<neg($x)>. The first variant
4309 needs to preserve $x since it does not know that it later will get overwritten.
4310 This makes a copy of $x and takes O(N), but $x->bneg() is O(1).
4312 =item Mixing different object types
4314 In Perl you will get a floating point value if you do one of the following:
4320 With overloaded math, only the first two variants will result in a BigFloat:
4325 $mbf = Math::BigFloat->new(5);
4326 $mbi2 = Math::BigInteger->new(5);
4327 $mbi = Math::BigInteger->new(2);
4329 # what actually gets called:
4330 $float = $mbf + $mbi; # $mbf->badd()
4331 $float = $mbf / $mbi; # $mbf->bdiv()
4332 $integer = $mbi + $mbf; # $mbi->badd()
4333 $integer = $mbi2 / $mbi; # $mbi2->bdiv()
4334 $integer = $mbi2 / $mbf; # $mbi2->bdiv()
4336 This is because math with overloaded operators follows the first (dominating)
4337 operand, and the operation of that is called and returns thus the result. So,
4338 Math::BigInt::bdiv() will always return a Math::BigInt, regardless whether
4339 the result should be a Math::BigFloat or the second operant is one.
4341 To get a Math::BigFloat you either need to call the operation manually,
4342 make sure the operands are already of the proper type or casted to that type
4343 via Math::BigFloat->new():
4345 $float = Math::BigFloat->new($mbi2) / $mbi; # = 2.5
4347 Beware of simple "casting" the entire expression, this would only convert
4348 the already computed result:
4350 $float = Math::BigFloat->new($mbi2 / $mbi); # = 2.0 thus wrong!
4352 Beware also of the order of more complicated expressions like:
4354 $integer = ($mbi2 + $mbi) / $mbf; # int / float => int
4355 $integer = $mbi2 / Math::BigFloat->new($mbi); # ditto
4357 If in doubt, break the expression into simpler terms, or cast all operands
4358 to the desired resulting type.
4360 Scalar values are a bit different, since:
4365 will both result in the proper type due to the way the overloaded math works.
4367 This section also applies to other overloaded math packages, like Math::String.
4369 One solution to you problem might be autoupgrading|upgrading. See the
4370 pragmas L<bignum>, L<bigint> and L<bigrat> for an easy way to do this.
4374 C<bsqrt()> works only good if the result is a big integer, e.g. the square
4375 root of 144 is 12, but from 12 the square root is 3, regardless of rounding
4376 mode. The reason is that the result is always truncated to an integer.
4378 If you want a better approximation of the square root, then use:
4380 $x = Math::BigFloat->new(12);
4381 Math::BigFloat->precision(0);
4382 Math::BigFloat->round_mode('even');
4383 print $x->copy->bsqrt(),"\n"; # 4
4385 Math::BigFloat->precision(2);
4386 print $x->bsqrt(),"\n"; # 3.46
4387 print $x->bsqrt(3),"\n"; # 3.464
4391 For negative numbers in base see also L<brsft|brsft>.
4397 This program is free software; you may redistribute it and/or modify it under
4398 the same terms as Perl itself.
4402 L<Math::BigFloat>, L<Math::BigRat> and L<Math::Big> as well as
4403 L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>.
4405 The pragmas L<bignum>, L<bigint> and L<bigrat> also might be of interest
4406 because they solve the autoupgrading/downgrading issue, at least partly.
4409 L<http://search.cpan.org/search?mode=module&query=Math%3A%3ABigInt> contains
4410 more documentation including a full version history, testcases, empty
4411 subclass files and benchmarks.
4415 Original code by Mark Biggar, overloaded interface by Ilya Zakharevich.
4416 Completely rewritten by Tels http://bloodgate.com in late 2000, 2001 - 2004
4417 and still at it in 2005.
4419 Many people contributed in one or more ways to the final beast, see the file
4420 CREDITS for an (uncomplete) list. If you miss your name, please drop me a