1 package Math::BigFloat;
4 # Mike grinned. 'Two down, infinity to go' - Mike Nostrus in 'Before and After'
7 # The following hash values are internally used:
8 # _e : exponent (ref to $CALC object)
9 # _m : mantissa (ref to $CALC object)
11 # sign : +,-,+inf,-inf, or "NaN" if not a number
19 @ISA = qw(Exporter Math::BigInt);
22 # $_trap_inf and $_trap_nan are internal and should never be accessed from the outside
23 use vars qw/$AUTOLOAD $accuracy $precision $div_scale $round_mode $rnd_mode
24 $upgrade $downgrade $_trap_nan $_trap_inf/;
25 my $class = "Math::BigFloat";
28 '<=>' => sub { $_[2] ?
29 ref($_[0])->bcmp($_[1],$_[0]) :
30 ref($_[0])->bcmp($_[0],$_[1])},
31 'int' => sub { $_[0]->as_number() }, # 'trunc' to bigint
34 ##############################################################################
35 # global constants, flags and assorted stuff
37 # the following are public, but their usage is not recommended. Use the
38 # accessor methods instead.
40 # class constants, use Class->constant_name() to access
41 $round_mode = 'even'; # one of 'even', 'odd', '+inf', '-inf', 'zero' or 'trunc'
48 # the package we are using for our private parts, defaults to:
49 # Math::BigInt->config()->{lib}
50 my $MBI = 'Math::BigInt::Calc';
52 # are NaNs ok? (otherwise it dies when encountering an NaN) set w/ config()
54 # the same for infinity
57 # constant for easier life
60 my $IMPORT = 0; # was import() called yet? used to make require work
62 # some digits of accuracy for blog(undef,10); which we use in blog() for speed
64 '2.3025850929940456840179914546843642076011014886287729760333279009675726097';
65 my $LOG_10_A = length($LOG_10)-1;
68 '0.6931471805599453094172321214581765680755001343602552541206800094933936220';
69 my $LOG_2_A = length($LOG_2)-1;
71 ##############################################################################
72 # the old code had $rnd_mode, so we need to support it, too
74 sub TIESCALAR { my ($class) = @_; bless \$round_mode, $class; }
75 sub FETCH { return $round_mode; }
76 sub STORE { $rnd_mode = $_[0]->round_mode($_[1]); }
80 # when someone set's $rnd_mode, we catch this and check the value to see
81 # whether it is valid or not.
82 $rnd_mode = 'even'; tie $rnd_mode, 'Math::BigFloat';
85 ##############################################################################
88 # valid method aliases for AUTOLOAD
89 my %methods = map { $_ => 1 }
90 qw / fadd fsub fmul fdiv fround ffround fsqrt fmod fstr fsstr fpow fnorm
91 fint facmp fcmp fzero fnan finf finc fdec flog ffac
92 fceil ffloor frsft flsft fone flog froot
94 # valid method's that can be hand-ed up (for AUTOLOAD)
95 my %hand_ups = map { $_ => 1 }
96 qw / is_nan is_inf is_negative is_positive is_pos is_neg
97 accuracy precision div_scale round_mode fneg fabs fnot
98 objectify upgrade downgrade
102 sub method_alias { exists $methods{$_[0]||''}; }
103 sub method_hand_up { exists $hand_ups{$_[0]||''}; }
106 ##############################################################################
111 # create a new BigFloat object from a string or another bigfloat object.
114 # sign => sign (+/-), or "NaN"
116 my ($class,$wanted,@r) = @_;
118 # avoid numify-calls by not using || on $wanted!
119 return $class->bzero() if !defined $wanted; # default to 0
120 return $wanted->copy() if UNIVERSAL::isa($wanted,'Math::BigFloat');
122 $class->import() if $IMPORT == 0; # make require work
124 my $self = {}; bless $self, $class;
125 # shortcut for bigints and its subclasses
126 if ((ref($wanted)) && (ref($wanted) ne $class))
128 $self->{_m} = $wanted->as_number()->{value}; # get us a bigint copy
129 $self->{_e} = $MBI->_zero();
131 $self->{sign} = $wanted->sign();
132 return $self->bnorm();
135 # handle '+inf', '-inf' first
136 if ($wanted =~ /^[+-]?inf$/)
138 return $downgrade->new($wanted) if $downgrade;
140 $self->{_e} = $MBI->_zero();
142 $self->{_m} = $MBI->_zero();
143 $self->{sign} = $wanted;
144 $self->{sign} = '+inf' if $self->{sign} eq 'inf';
145 return $self->bnorm();
148 my ($mis,$miv,$mfv,$es,$ev) = Math::BigInt::_split($wanted);
154 Carp::croak ("$wanted is not a number initialized to $class");
157 return $downgrade->bnan() if $downgrade;
159 $self->{_e} = $MBI->_zero();
161 $self->{_m} = $MBI->_zero();
162 $self->{sign} = $nan;
166 # make integer from mantissa by adjusting exp, then convert to int
167 $self->{_e} = $MBI->_new($$ev); # exponent
168 $self->{_es} = $$es || '+';
169 my $mantissa = "$$miv$$mfv"; # create mant.
170 $mantissa =~ s/^0+(\d)/$1/; # strip leading zeros
171 $self->{_m} = $MBI->_new($mantissa); # create mant.
173 # 3.123E0 = 3123E-3, and 3.123E-2 => 3123E-5
174 if (CORE::length($$mfv) != 0)
176 my $len = $MBI->_new( CORE::length($$mfv));
177 ($self->{_e}, $self->{_es}) =
178 _e_sub ($self->{_e}, $len, $self->{_es}, '+');
180 $self->{sign} = $$mis;
182 # we can only have trailing zeros on the mantissa of $$mfv eq ''
183 if (CORE::length($$mfv) == 0)
185 my $zeros = $MBI->_zeros($self->{_m}); # correct for trailing zeros
188 my $z = $MBI->_new($zeros);
189 $MBI->_rsft ( $self->{_m}, $z, 10);
190 _e_add ( $self->{_e}, $z, $self->{_es}, '+');
193 # for something like 0Ey, set y to 1, and -0 => +0
194 $self->{sign} = '+', $self->{_e} = $MBI->_one()
195 if $MBI->_is_zero($self->{_m});
196 return $self->round(@r) if !$downgrade;
198 # if downgrade, inf, NaN or integers go down
200 if ($downgrade && $self->{_es} eq '+')
202 if ($MBI->_is_zero( $self->{_e} ))
204 return $downgrade->new($$mis . $MBI->_str( $self->{_m} ));
206 return $downgrade->new($self->bsstr());
208 $self->bnorm()->round(@r); # first normalize, then round
216 # if two arguments, the first one is the class to "swallow" subclasses
224 return unless ref($x); # only for objects
226 my $self = {}; bless $self,$c;
228 $self->{sign} = $x->{sign};
229 $self->{_es} = $x->{_es};
230 $self->{_m} = $MBI->_copy($x->{_m});
231 $self->{_e} = $MBI->_copy($x->{_e});
232 $self->{_a} = $x->{_a} if defined $x->{_a};
233 $self->{_p} = $x->{_p} if defined $x->{_p};
239 # used by parent class bone() to initialize number to NaN
245 my $class = ref($self);
246 Carp::croak ("Tried to set $self to NaN in $class\::_bnan()");
249 $IMPORT=1; # call our import only once
250 $self->{_m} = $MBI->_zero();
251 $self->{_e} = $MBI->_zero();
257 # used by parent class bone() to initialize number to +-inf
263 my $class = ref($self);
264 Carp::croak ("Tried to set $self to +-inf in $class\::_binf()");
267 $IMPORT=1; # call our import only once
268 $self->{_m} = $MBI->_zero();
269 $self->{_e} = $MBI->_zero();
275 # used by parent class bone() to initialize number to 1
277 $IMPORT=1; # call our import only once
278 $self->{_m} = $MBI->_one();
279 $self->{_e} = $MBI->_zero();
285 # used by parent class bone() to initialize number to 0
287 $IMPORT=1; # call our import only once
288 $self->{_m} = $MBI->_zero();
289 $self->{_e} = $MBI->_one();
295 my ($self,$class) = @_;
296 return if $class =~ /^Math::BigInt/; # we aren't one of these
297 UNIVERSAL::isa($self,$class);
302 # return (later set?) configuration data as hash ref
303 my $class = shift || 'Math::BigFloat';
305 my $cfg = $class->SUPER::config(@_);
307 # now we need only to override the ones that are different from our parent
308 $cfg->{class} = $class;
313 ##############################################################################
314 # string conversation
318 # (ref to BFLOAT or num_str ) return num_str
319 # Convert number from internal format to (non-scientific) string format.
320 # internal format is always normalized (no leading zeros, "-0" => "+0")
321 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
323 if ($x->{sign} !~ /^[+-]$/)
325 return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
329 my $es = '0'; my $len = 1; my $cad = 0; my $dot = '.';
332 my $not_zero = !($x->{sign} eq '+' && $MBI->_is_zero($x->{_m}));
335 $es = $MBI->_str($x->{_m});
336 $len = CORE::length($es);
337 my $e = $MBI->_num($x->{_e});
338 $e = -$e if $x->{_es} eq '-';
342 # if _e is bigger than a scalar, the following will blow your memory
345 my $r = abs($e) - $len;
346 $es = '0.'. ('0' x $r) . $es; $cad = -($len+$r);
350 substr($es,$e,0) = '.'; $cad = $MBI->_num($x->{_e});
351 $cad = -$cad if $x->{_es} eq '-';
357 $es .= '0' x $e; $len += $e; $cad = 0;
361 $es = '-'.$es if $x->{sign} eq '-';
362 # if set accuracy or precision, pad with zeros on the right side
363 if ((defined $x->{_a}) && ($not_zero))
365 # 123400 => 6, 0.1234 => 4, 0.001234 => 4
366 my $zeros = $x->{_a} - $cad; # cad == 0 => 12340
367 $zeros = $x->{_a} - $len if $cad != $len;
368 $es .= $dot.'0' x $zeros if $zeros > 0;
370 elsif ((($x->{_p} || 0) < 0))
372 # 123400 => 6, 0.1234 => 4, 0.001234 => 6
373 my $zeros = -$x->{_p} + $cad;
374 $es .= $dot.'0' x $zeros if $zeros > 0;
381 # (ref to BFLOAT or num_str ) return num_str
382 # Convert number from internal format to scientific string format.
383 # internal format is always normalized (no leading zeros, "-0E0" => "+0E0")
384 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
386 if ($x->{sign} !~ /^[+-]$/)
388 return $x->{sign} unless $x->{sign} eq '+inf'; # -inf, NaN
391 my $sep = 'e'.$x->{_es};
392 my $sign = $x->{sign}; $sign = '' if $sign eq '+';
393 $sign . $MBI->_str($x->{_m}) . $sep . $MBI->_str($x->{_e});
398 # Make a number from a BigFloat object
399 # simple return a string and let Perl's atoi()/atof() handle the rest
400 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
404 ##############################################################################
405 # public stuff (usually prefixed with "b")
408 # XXX TODO this must be overwritten and return NaN for non-integer values
409 # band(), bior(), bxor(), too
412 # $class->SUPER::bnot($class,@_);
417 # Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort)
420 my ($self,$x,$y) = (ref($_[0]),@_);
421 # objectify is costly, so avoid it
422 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
424 ($self,$x,$y) = objectify(2,@_);
427 return $upgrade->bcmp($x,$y) if defined $upgrade &&
428 ((!$x->isa($self)) || (!$y->isa($self)));
430 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
432 # handle +-inf and NaN
433 return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
434 return 0 if ($x->{sign} eq $y->{sign}) && ($x->{sign} =~ /^[+-]inf$/);
435 return +1 if $x->{sign} eq '+inf';
436 return -1 if $x->{sign} eq '-inf';
437 return -1 if $y->{sign} eq '+inf';
441 # check sign for speed first
442 return 1 if $x->{sign} eq '+' && $y->{sign} eq '-'; # does also 0 <=> -y
443 return -1 if $x->{sign} eq '-' && $y->{sign} eq '+'; # does also -x <=> 0
446 my $xz = $x->is_zero();
447 my $yz = $y->is_zero();
448 return 0 if $xz && $yz; # 0 <=> 0
449 return -1 if $xz && $y->{sign} eq '+'; # 0 <=> +y
450 return 1 if $yz && $x->{sign} eq '+'; # +x <=> 0
452 # adjust so that exponents are equal
453 my $lxm = $MBI->_len($x->{_m});
454 my $lym = $MBI->_len($y->{_m});
455 # the numify somewhat limits our length, but makes it much faster
456 my ($xes,$yes) = (1,1);
457 $xes = -1 if $x->{_es} ne '+';
458 $yes = -1 if $y->{_es} ne '+';
459 my $lx = $lxm + $xes * $MBI->_num($x->{_e});
460 my $ly = $lym + $yes * $MBI->_num($y->{_e});
461 my $l = $lx - $ly; $l = -$l if $x->{sign} eq '-';
462 return $l <=> 0 if $l != 0;
464 # lengths (corrected by exponent) are equal
465 # so make mantissa equal length by padding with zero (shift left)
466 my $diff = $lxm - $lym;
467 my $xm = $x->{_m}; # not yet copy it
471 $ym = $MBI->_copy($y->{_m});
472 $ym = $MBI->_lsft($ym, $MBI->_new($diff), 10);
476 $xm = $MBI->_copy($x->{_m});
477 $xm = $MBI->_lsft($xm, $MBI->_new(-$diff), 10);
479 my $rc = $MBI->_acmp($xm,$ym);
480 $rc = -$rc if $x->{sign} eq '-'; # -124 < -123
486 # Compares 2 values, ignoring their signs.
487 # Returns one of undef, <0, =0, >0. (suitable for sort)
490 my ($self,$x,$y) = (ref($_[0]),@_);
491 # objectify is costly, so avoid it
492 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
494 ($self,$x,$y) = objectify(2,@_);
497 return $upgrade->bacmp($x,$y) if defined $upgrade &&
498 ((!$x->isa($self)) || (!$y->isa($self)));
500 # handle +-inf and NaN's
501 if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/)
503 return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
504 return 0 if ($x->is_inf() && $y->is_inf());
505 return 1 if ($x->is_inf() && !$y->is_inf());
510 my $xz = $x->is_zero();
511 my $yz = $y->is_zero();
512 return 0 if $xz && $yz; # 0 <=> 0
513 return -1 if $xz && !$yz; # 0 <=> +y
514 return 1 if $yz && !$xz; # +x <=> 0
516 # adjust so that exponents are equal
517 my $lxm = $MBI->_len($x->{_m});
518 my $lym = $MBI->_len($y->{_m});
519 my ($xes,$yes) = (1,1);
520 $xes = -1 if $x->{_es} ne '+';
521 $yes = -1 if $y->{_es} ne '+';
522 # the numify somewhat limits our length, but makes it much faster
523 my $lx = $lxm + $xes * $MBI->_num($x->{_e});
524 my $ly = $lym + $yes * $MBI->_num($y->{_e});
526 return $l <=> 0 if $l != 0;
528 # lengths (corrected by exponent) are equal
529 # so make mantissa equal-length by padding with zero (shift left)
530 my $diff = $lxm - $lym;
531 my $xm = $x->{_m}; # not yet copy it
535 $ym = $MBI->_copy($y->{_m});
536 $ym = $MBI->_lsft($ym, $MBI->_new($diff), 10);
540 $xm = $MBI->_copy($x->{_m});
541 $xm = $MBI->_lsft($xm, $MBI->_new(-$diff), 10);
543 $MBI->_acmp($xm,$ym);
548 # add second arg (BFLOAT or string) to first (BFLOAT) (modifies first)
549 # return result as BFLOAT
552 my ($self,$x,$y,$a,$p,$r) = (ref($_[0]),@_);
553 # objectify is costly, so avoid it
554 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
556 ($self,$x,$y,$a,$p,$r) = objectify(2,@_);
559 # inf and NaN handling
560 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
563 return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
565 if (($x->{sign} =~ /^[+-]inf$/) && ($y->{sign} =~ /^[+-]inf$/))
567 # +inf++inf or -inf+-inf => same, rest is NaN
568 return $x if $x->{sign} eq $y->{sign};
571 # +-inf + something => +inf; something +-inf => +-inf
572 $x->{sign} = $y->{sign}, return $x if $y->{sign} =~ /^[+-]inf$/;
576 return $upgrade->badd($x,$y,$a,$p,$r) if defined $upgrade &&
577 ((!$x->isa($self)) || (!$y->isa($self)));
579 # speed: no add for 0+y or x+0
580 return $x->bround($a,$p,$r) if $y->is_zero(); # x+0
581 if ($x->is_zero()) # 0+y
583 # make copy, clobbering up x (modify in place!)
584 $x->{_e} = $MBI->_copy($y->{_e});
585 $x->{_es} = $y->{_es};
586 $x->{_m} = $MBI->_copy($y->{_m});
587 $x->{sign} = $y->{sign} || $nan;
588 return $x->round($a,$p,$r,$y);
591 # take lower of the two e's and adapt m1 to it to match m2
593 $e = $MBI->_zero() if !defined $e; # if no BFLOAT?
594 $e = $MBI->_copy($e); # make copy (didn't do it yet)
598 ($e,$es) = _e_sub($e, $x->{_e}, $y->{_es} || '+', $x->{_es});
600 my $add = $MBI->_copy($y->{_m});
602 if ($es eq '-') # < 0
604 $MBI->_lsft( $x->{_m}, $e, 10);
605 ($x->{_e},$x->{_es}) = _e_add($x->{_e}, $e, $x->{_es}, $es);
607 elsif (!$MBI->_is_zero($e)) # > 0
609 $MBI->_lsft($add, $e, 10);
611 # else: both e are the same, so just leave them
613 if ($x->{sign} eq $y->{sign})
616 $x->{_m} = $MBI->_add($x->{_m}, $add);
620 ($x->{_m}, $x->{sign}) =
621 _e_add($x->{_m}, $add, $x->{sign}, $y->{sign});
624 # delete trailing zeros, then round
625 $x->bnorm()->round($a,$p,$r,$y);
630 # (BigFloat or num_str, BigFloat or num_str) return BigFloat
631 # subtract second arg from first, modify first
634 my ($self,$x,$y,$a,$p,$r) = (ref($_[0]),@_);
635 # objectify is costly, so avoid it
636 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
638 ($self,$x,$y,$a,$p,$r) = objectify(2,@_);
641 if ($y->is_zero()) # still round for not adding zero
643 return $x->round($a,$p,$r);
647 $y->{sign} =~ tr/+-/-+/; # does nothing for NaN
648 $x->badd($y,$a,$p,$r); # badd does not leave internal zeros
649 $y->{sign} =~ tr/+-/-+/; # refix $y (does nothing for NaN)
650 $x; # already rounded by badd()
655 # increment arg by one
656 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
658 if ($x->{_es} eq '-')
660 return $x->badd($self->bone(),@r); # digits after dot
663 if (!$MBI->_is_zero($x->{_e})) # _e == 0 for NaN, inf, -inf
665 # 1e2 => 100, so after the shift below _m has a '0' as last digit
666 $x->{_m} = $MBI->_lsft($x->{_m}, $x->{_e},10); # 1e2 => 100
667 $x->{_e} = $MBI->_zero(); # normalize
669 # we know that the last digit of $x will be '1' or '9', depending on the
673 if ($x->{sign} eq '+')
675 $MBI->_inc($x->{_m});
676 return $x->bnorm()->bround(@r);
678 elsif ($x->{sign} eq '-')
680 $MBI->_dec($x->{_m});
681 $x->{sign} = '+' if $MBI->_is_zero($x->{_m}); # -1 +1 => -0 => +0
682 return $x->bnorm()->bround(@r);
684 # inf, nan handling etc
685 $x->badd($self->bone(),@r); # badd() does round
690 # decrement arg by one
691 my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
693 if ($x->{_es} eq '-')
695 return $x->badd($self->bone('-'),@r); # digits after dot
698 if (!$MBI->_is_zero($x->{_e}))
700 $x->{_m} = $MBI->_lsft($x->{_m}, $x->{_e},10); # 1e2 => 100
701 $x->{_e} = $MBI->_zero(); # normalize
705 my $zero = $x->is_zero();
707 if (($x->{sign} eq '-') || $zero)
709 $MBI->_inc($x->{_m});
710 $x->{sign} = '-' if $zero; # 0 => 1 => -1
711 $x->{sign} = '+' if $MBI->_is_zero($x->{_m}); # -1 +1 => -0 => +0
712 return $x->bnorm()->round(@r);
715 elsif ($x->{sign} eq '+')
717 $MBI->_dec($x->{_m});
718 return $x->bnorm()->round(@r);
720 # inf, nan handling etc
721 $x->badd($self->bone('-'),@r); # does round
728 my ($self,$x,$base,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
730 # $base > 0, $base != 1; if $base == undef default to $base == e
733 # we need to limit the accuracy to protect against overflow
736 ($x,@params) = $x->_find_round_parameters($a,$p,$r);
738 # also takes care of the "error in _find_round_parameters?" case
739 return $x->bnan() if $x->{sign} ne '+' || $x->is_zero();
742 # no rounding at all, so must use fallback
743 if (scalar @params == 0)
745 # simulate old behaviour
746 $params[0] = $self->div_scale(); # and round to it as accuracy
747 $params[1] = undef; # P = undef
748 $scale = $params[0]+4; # at least four more for proper round
749 $params[2] = $r; # round mode by caller or undef
750 $fallback = 1; # to clear a/p afterwards
754 # the 4 below is empirical, and there might be cases where it is not
756 $scale = abs($params[0] || $params[1]) + 4; # take whatever is defined
759 return $x->bzero(@params) if $x->is_one();
760 # base not defined => base == Euler's constant e
763 # make object, since we don't feed it through objectify() to still get the
764 # case of $base == undef
765 $base = $self->new($base) unless ref($base);
766 # $base > 0; $base != 1
767 return $x->bnan() if $base->is_zero() || $base->is_one() ||
768 $base->{sign} ne '+';
769 # if $x == $base, we know the result must be 1.0
770 return $x->bone('+',@params) if $x->bcmp($base) == 0;
773 # when user set globals, they would interfere with our calculation, so
774 # disable them and later re-enable them
776 my $abr = "$self\::accuracy"; my $ab = $$abr; $$abr = undef;
777 my $pbr = "$self\::precision"; my $pb = $$pbr; $$pbr = undef;
778 # we also need to disable any set A or P on $x (_find_round_parameters took
779 # them already into account), since these would interfere, too
780 delete $x->{_a}; delete $x->{_p};
781 # need to disable $upgrade in BigInt, to avoid deep recursion
782 local $Math::BigInt::upgrade = undef;
783 local $Math::BigFloat::downgrade = undef;
785 # upgrade $x if $x is not a BigFloat (handle BigInt input)
786 if (!$x->isa('Math::BigFloat'))
788 $x = Math::BigFloat->new($x);
794 # If the base is defined and an integer, try to calculate integer result
795 # first. This is very fast, and in case the real result was found, we can
797 if (defined $base && $base->is_int() && $x->is_int())
799 my $i = $MBI->_copy( $x->{_m} );
800 $MBI->_lsft( $i, $x->{_e}, 10 ) unless $MBI->_is_zero($x->{_e});
801 my $int = Math::BigInt->bzero();
803 $int->blog($base->as_number());
805 if ($base->as_number()->bpow($int) == $x)
807 # found result, return it
808 $x->{_m} = $int->{value};
809 $x->{_e} = $MBI->_zero();
818 # first calculate the log to base e (using reduction by 10 (and probably 2))
819 $self->_log_10($x,$scale);
821 # and if a different base was requested, convert it
824 $base = Math::BigFloat->new($base) unless $base->isa('Math::BigFloat');
825 # not ln, but some other base (don't modify $base)
826 $x->bdiv( $base->copy()->blog(undef,$scale), $scale );
830 # shortcut to not run through _find_round_parameters again
831 if (defined $params[0])
833 $x->bround($params[0],$params[2]); # then round accordingly
837 $x->bfround($params[1],$params[2]); # then round accordingly
841 # clear a/p after round, since user did not request it
842 delete $x->{_a}; delete $x->{_p};
845 $$abr = $ab; $$pbr = $pb;
852 # internal log function to calculate ln() based on Taylor series.
853 # Modifies $x in place.
854 my ($self,$x,$scale) = @_;
856 # in case of $x == 1, result is 0
857 return $x->bzero() if $x->is_one();
859 # http://www.efunda.com/math/taylor_series/logarithmic.cfm?search_string=log
863 # Taylor: | u 1 u^3 1 u^5 |
864 # ln (x) = 2 | --- + - * --- + - * --- + ... | x > 0
865 # |_ v 3 v^3 5 v^5 _|
867 # This takes much more steps to calculate the result and is thus not used
870 # Taylor: | u 1 u^2 1 u^3 |
871 # ln (x) = 2 | --- + - * --- + - * --- + ... | x > 1/2
872 # |_ x 2 x^2 3 x^3 _|
874 my ($limit,$v,$u,$below,$factor,$two,$next,$over,$f);
876 $v = $x->copy(); $v->binc(); # v = x+1
877 $x->bdec(); $u = $x->copy(); # u = x-1; x = x-1
878 $x->bdiv($v,$scale); # first term: u/v
881 $u *= $u; $v *= $v; # u^2, v^2
882 $below->bmul($v); # u^3, v^3
884 $factor = $self->new(3); $f = $self->new(2);
886 my $steps = 0 if DEBUG;
887 $limit = $self->new("1E-". ($scale-1));
890 # we calculate the next term, and add it to the last
891 # when the next term is below our limit, it won't affect the outcome
892 # anymore, so we stop
894 # calculating the next term simple from over/below will result in quite
895 # a time hog if the input has many digits, since over and below will
896 # accumulate more and more digits, and the result will also have many
897 # digits, but in the end it is rounded to $scale digits anyway. So if we
898 # round $over and $below first, we save a lot of time for the division
899 # (not with log(1.2345), but try log (123**123) to see what I mean. This
900 # can introduce a rounding error if the division result would be f.i.
901 # 0.1234500000001 and we round it to 5 digits it would become 0.12346, but
902 # if we truncated $over and $below we might get 0.12345. Does this matter
903 # for the end result? So we give $over and $below 4 more digits to be
904 # on the safe side (unscientific error handling as usual... :+D
906 $next = $over->copy->bround($scale+4)->bdiv(
907 $below->copy->bmul($factor)->bround($scale+4),
911 ## $next = $over->copy()->bdiv($below->copy()->bmul($factor),$scale);
913 last if $next->bacmp($limit) <= 0;
915 delete $next->{_a}; delete $next->{_p};
917 # calculate things for the next term
918 $over *= $u; $below *= $v; $factor->badd($f);
921 $steps++; print "step $steps = $x\n" if $steps % 10 == 0;
924 $x->bmul($f); # $x *= 2
925 print "took $steps steps\n" if DEBUG;
930 # Internal log function based on reducing input to the range of 0.1 .. 9.99
931 # and then "correcting" the result to the proper one. Modifies $x in place.
932 my ($self,$x,$scale) = @_;
934 # taking blog() from numbers greater than 10 takes a *very long* time, so we
935 # break the computation down into parts based on the observation that:
936 # blog(x*y) = blog(x) + blog(y)
937 # We set $y here to multiples of 10 so that $x is below 1 (the smaller $x is
938 # the faster it get's, especially because 2*$x takes about 10 times as long,
939 # so by dividing $x by 10 we make it at least factor 100 faster...)
941 # The same observation is valid for numbers smaller than 0.1 (e.g. computing
942 # log(1) is fastest, and the farther away we get from 1, the longer it takes)
943 # so we also 'break' this down by multiplying $x with 10 and subtract the
944 # log(10) afterwards to get the correct result.
946 # calculate nr of digits before dot
947 my $dbd = $MBI->_num($x->{_e});
948 $dbd = -$dbd if $x->{_es} eq '-';
949 $dbd += $MBI->_len($x->{_m});
951 # more than one digit (e.g. at least 10), but *not* exactly 10 to avoid
954 my $calc = 1; # do some calculation?
956 # disable the shortcut for 10, since we need log(10) and this would recurse
958 if ($x->{_es} eq '+' && $MBI->_is_one($x->{_e}) && $MBI->_is_one($x->{_m}))
960 $dbd = 0; # disable shortcut
961 # we can use the cached value in these cases
962 if ($scale <= $LOG_10_A)
964 $x->bzero(); $x->badd($LOG_10);
965 $calc = 0; # no need to calc, but round
970 # disable the shortcut for 2, since we maybe have it cached
971 if (($MBI->_is_zero($x->{_e}) && $MBI->_is_two($x->{_m})))
973 $dbd = 0; # disable shortcut
974 # we can use the cached value in these cases
975 if ($scale <= $LOG_2_A)
977 $x->bzero(); $x->badd($LOG_2);
978 $calc = 0; # no need to calc, but round
983 # if $x = 0.1, we know the result must be 0-log(10)
984 if ($calc != 0 && $x->{_es} eq '-' && $MBI->_is_one($x->{_e}) &&
985 $MBI->_is_one($x->{_m}))
987 $dbd = 0; # disable shortcut
988 # we can use the cached value in these cases
989 if ($scale <= $LOG_10_A)
991 $x->bzero(); $x->bsub($LOG_10);
992 $calc = 0; # no need to calc, but round
996 return if $calc == 0; # already have the result
998 # default: these correction factors are undef and thus not used
999 my $l_10; # value of ln(10) to A of $scale
1000 my $l_2; # value of ln(2) to A of $scale
1002 # $x == 2 => 1, $x == 13 => 2, $x == 0.1 => 0, $x == 0.01 => -1
1003 # so don't do this shortcut for 1 or 0
1004 if (($dbd > 1) || ($dbd < 0))
1006 # convert our cached value to an object if not already (avoid doing this
1007 # at import() time, since not everybody needs this)
1008 $LOG_10 = $self->new($LOG_10,undef,undef) unless ref $LOG_10;
1010 #print "x = $x, dbd = $dbd, calc = $calc\n";
1011 # got more than one digit before the dot, or more than one zero after the
1013 # log(123) == log(1.23) + log(10) * 2
1014 # log(0.0123) == log(1.23) - log(10) * 2
1016 if ($scale <= $LOG_10_A)
1019 $l_10 = $LOG_10->copy(); # copy for mul
1023 # else: slower, compute it (but don't cache it, because it could be big)
1024 # also disable downgrade for this code path
1025 local $Math::BigFloat::downgrade = undef;
1026 $l_10 = $self->new(10)->blog(undef,$scale); # scale+4, actually
1028 $dbd-- if ($dbd > 1); # 20 => dbd=2, so make it dbd=1
1029 $l_10->bmul( $self->new($dbd)); # log(10) * (digits_before_dot-1)
1036 ($x->{_e}, $x->{_es}) =
1037 _e_sub( $x->{_e}, $MBI->_new($dbd), $x->{_es}, $dbd_sign); # 123 => 1.23
1041 # Now: 0.1 <= $x < 10 (and possible correction in l_10)
1043 ### Since $x in the range 0.5 .. 1.5 is MUCH faster, we do a repeated div
1044 ### or mul by 2 (maximum times 3, since x < 10 and x > 0.1)
1046 my $half = $self->new('0.5');
1047 my $twos = 0; # default: none (0 times)
1048 my $two = $self->new(2);
1049 while ($x->bacmp($half) <= 0)
1051 $twos--; $x->bmul($two);
1053 while ($x->bacmp($two) >= 0)
1055 $twos++; $x->bdiv($two,$scale+4); # keep all digits
1057 # $twos > 0 => did mul 2, < 0 => did div 2 (never both)
1058 # calculate correction factor based on ln(2)
1061 $LOG_2 = $self->new($LOG_2,undef,undef) unless ref $LOG_2;
1062 if ($scale <= $LOG_2_A)
1065 $l_2 = $LOG_2->copy(); # copy for mul
1069 # else: slower, compute it (but don't cache it, because it could be big)
1070 # also disable downgrade for this code path
1071 local $Math::BigFloat::downgrade = undef;
1072 $l_2 = $two->blog(undef,$scale); # scale+4, actually
1074 $l_2->bmul($twos); # * -2 => subtract, * 2 => add
1077 $self->_log($x,$scale); # need to do the "normal" way
1078 $x->badd($l_10) if defined $l_10; # correct it by ln(10)
1079 $x->badd($l_2) if defined $l_2; # and maybe by ln(2)
1080 # all done, $x contains now the result
1085 # (BFLOAT or num_str, BFLOAT or num_str) return BFLOAT
1086 # does not modify arguments, but returns new object
1087 # Lowest Common Multiplicator
1089 my ($self,@arg) = objectify(0,@_);
1090 my $x = $self->new(shift @arg);
1091 while (@arg) { $x = _lcm($x,shift @arg); }
1097 # (BFLOAT or num_str, BFLOAT or num_str) return BINT
1098 # does not modify arguments, but returns new object
1099 # GCD -- Euclids algorithm Knuth Vol 2 pg 296
1101 my ($self,@arg) = objectify(0,@_);
1102 my $x = $self->new(shift @arg);
1103 while (@arg) { $x = _gcd($x,shift @arg); }
1107 ##############################################################################
1111 # Internal helper sub to take two positive integers and their signs and
1112 # then add them. Input ($CALC,$CALC,('+'|'-'),('+'|'-')),
1113 # output ($CALC,('+'|'-'))
1114 my ($x,$y,$xs,$ys) = @_;
1116 # if the signs are equal we can add them (-5 + -3 => -(5 + 3) => -8)
1119 $x = $MBI->_add ($x, $y ); # a+b
1120 # the sign follows $xs
1124 my $a = $MBI->_acmp($x,$y);
1127 $x = $MBI->_sub ($x , $y); # abs sub
1131 $x = $MBI->_zero(); # result is 0
1136 $x = $MBI->_sub ( $y, $x, 1 ); # abs sub
1144 # Internal helper sub to take two positive integers and their signs and
1145 # then subtract them. Input ($CALC,$CALC,('+'|'-'),('+'|'-')),
1146 # output ($CALC,('+'|'-'))
1147 my ($x,$y,$xs,$ys) = @_;
1151 _e_add($x,$y,$xs,$ys); # call add (does subtract now)
1154 ###############################################################################
1155 # is_foo methods (is_negative, is_positive are inherited from BigInt)
1159 # return true if arg (BFLOAT or num_str) is an integer
1160 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1162 return 1 if ($x->{sign} =~ /^[+-]$/) && # NaN and +-inf aren't
1163 $x->{_es} eq '+'; # 1e-1 => no integer
1169 # return true if arg (BFLOAT or num_str) is zero
1170 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1172 return 1 if $x->{sign} eq '+' && $MBI->_is_zero($x->{_m});
1178 # return true if arg (BFLOAT or num_str) is +1 or -1 if signis given
1179 my ($self,$x,$sign) = ref($_[0]) ? (undef,@_) : objectify(1,@_);
1181 $sign = '+' if !defined $sign || $sign ne '-';
1183 if ($x->{sign} eq $sign &&
1184 $MBI->_is_zero($x->{_e}) && $MBI->_is_one($x->{_m}));
1190 # return true if arg (BFLOAT or num_str) is odd or false if even
1191 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1193 return 1 if ($x->{sign} =~ /^[+-]$/) && # NaN & +-inf aren't
1194 ($MBI->_is_zero($x->{_e}) && $MBI->_is_odd($x->{_m}));
1200 # return true if arg (BINT or num_str) is even or false if odd
1201 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
1203 return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't
1204 return 1 if ($x->{_es} eq '+' # 123.45 is never
1205 && $MBI->_is_even($x->{_m})); # but 1200 is
1211 # multiply two numbers -- stolen from Knuth Vol 2 pg 233
1212 # (BINT or num_str, BINT or num_str) return BINT
1215 my ($self,$x,$y,$a,$p,$r) = (ref($_[0]),@_);
1216 # objectify is costly, so avoid it
1217 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1219 ($self,$x,$y,$a,$p,$r) = objectify(2,@_);
1222 return $x->bnan() if (($x->{sign} eq $nan) || ($y->{sign} eq $nan));
1225 if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/))
1227 return $x->bnan() if $x->is_zero() || $y->is_zero();
1228 # result will always be +-inf:
1229 # +inf * +/+inf => +inf, -inf * -/-inf => +inf
1230 # +inf * -/-inf => -inf, -inf * +/+inf => -inf
1231 return $x->binf() if ($x->{sign} =~ /^\+/ && $y->{sign} =~ /^\+/);
1232 return $x->binf() if ($x->{sign} =~ /^-/ && $y->{sign} =~ /^-/);
1233 return $x->binf('-');
1236 return $x->bzero() if $x->is_zero() || $y->is_zero();
1238 return $upgrade->bmul($x,$y,$a,$p,$r) if defined $upgrade &&
1239 ((!$x->isa($self)) || (!$y->isa($self)));
1241 # aEb * cEd = (a*c)E(b+d)
1242 $MBI->_mul($x->{_m},$y->{_m});
1243 ($x->{_e}, $x->{_es}) = _e_add($x->{_e}, $y->{_e}, $x->{_es}, $y->{_es});
1246 $x->{sign} = $x->{sign} ne $y->{sign} ? '-' : '+';
1247 return $x->bnorm()->round($a,$p,$r,$y);
1252 # (dividend: BFLOAT or num_str, divisor: BFLOAT or num_str) return
1253 # (BFLOAT,BFLOAT) (quo,rem) or BFLOAT (only rem)
1256 my ($self,$x,$y,$a,$p,$r) = (ref($_[0]),@_);
1257 # objectify is costly, so avoid it
1258 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1260 ($self,$x,$y,$a,$p,$r) = objectify(2,@_);
1263 return $self->_div_inf($x,$y)
1264 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero());
1266 # x== 0 # also: or y == 1 or y == -1
1267 return wantarray ? ($x,$self->bzero()) : $x if $x->is_zero();
1270 return $upgrade->bdiv($upgrade->new($x),$y,$a,$p,$r) if defined $upgrade;
1272 # we need to limit the accuracy to protect against overflow
1274 my (@params,$scale);
1275 ($x,@params) = $x->_find_round_parameters($a,$p,$r,$y);
1277 return $x if $x->is_nan(); # error in _find_round_parameters?
1279 # no rounding at all, so must use fallback
1280 if (scalar @params == 0)
1282 # simulate old behaviour
1283 $params[0] = $self->div_scale(); # and round to it as accuracy
1284 $scale = $params[0]+4; # at least four more for proper round
1285 $params[2] = $r; # round mode by caller or undef
1286 $fallback = 1; # to clear a/p afterwards
1290 # the 4 below is empirical, and there might be cases where it is not
1292 $scale = abs($params[0] || $params[1]) + 4; # take whatever is defined
1294 my $lx = $MBI->_len($x->{_m}); my $ly = $MBI->_len($y->{_m});
1295 $scale = $lx if $lx > $scale;
1296 $scale = $ly if $ly > $scale;
1297 my $diff = $ly - $lx;
1298 $scale += $diff if $diff > 0; # if lx << ly, but not if ly << lx!
1300 # make copy of $x in case of list context for later reminder calculation
1302 if (wantarray && !$y->is_one())
1307 $x->{sign} = $x->{sign} ne $y->sign() ? '-' : '+';
1309 # check for / +-1 ( +/- 1E0)
1312 # promote BigInts and it's subclasses (except when already a BigFloat)
1313 $y = $self->new($y) unless $y->isa('Math::BigFloat');
1315 # calculate the result to $scale digits and then round it
1316 # a * 10 ** b / c * 10 ** d => a/c * 10 ** (b-d)
1317 $MBI->_lsft($x->{_m},$MBI->_new($scale),10);
1318 $MBI->_div ($x->{_m},$y->{_m} ); # a/c
1320 ($x->{_e},$x->{_es}) =
1321 _e_sub($x->{_e}, $y->{_e}, $x->{_es}, $y->{_es});
1322 # correct for 10**scale
1323 ($x->{_e},$x->{_es}) =
1324 _e_sub($x->{_e}, $MBI->_new($scale), $x->{_es}, '+');
1325 $x->bnorm(); # remove trailing 0's
1328 # shortcut to not run through _find_round_parameters again
1329 if (defined $params[0])
1331 delete $x->{_a}; # clear before round
1332 $x->bround($params[0],$params[2]); # then round accordingly
1336 delete $x->{_p}; # clear before round
1337 $x->bfround($params[1],$params[2]); # then round accordingly
1341 # clear a/p after round, since user did not request it
1342 delete $x->{_a}; delete $x->{_p};
1349 $rem->bmod($y,@params); # copy already done
1353 $rem = $self->bzero();
1357 # clear a/p after round, since user did not request it
1358 delete $rem->{_a}; delete $rem->{_p};
1367 # (dividend: BFLOAT or num_str, divisor: BFLOAT or num_str) return reminder
1370 my ($self,$x,$y,$a,$p,$r) = (ref($_[0]),@_);
1371 # objectify is costly, so avoid it
1372 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1374 ($self,$x,$y,$a,$p,$r) = objectify(2,@_);
1377 # handle NaN, inf, -inf
1378 if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/))
1380 my ($d,$re) = $self->SUPER::_div_inf($x,$y);
1381 $x->{sign} = $re->{sign};
1382 $x->{_e} = $re->{_e};
1383 $x->{_m} = $re->{_m};
1384 return $x->round($a,$p,$r,$y);
1388 return $x->bnan() if $x->is_zero();
1391 return $x->bzero() if $y->is_one() || $x->is_zero();
1393 my $cmp = $x->bacmp($y); # equal or $x < $y?
1394 return $x->bzero($a,$p) if $cmp == 0; # $x == $y => result 0
1396 # only $y of the operands negative?
1397 my $neg = 0; $neg = 1 if $x->{sign} ne $y->{sign};
1399 $x->{sign} = $y->{sign}; # calc sign first
1400 return $x->round($a,$p,$r) if $cmp < 0 && $neg == 0; # $x < $y => result $x
1402 my $ym = $MBI->_copy($y->{_m});
1405 $MBI->_lsft( $ym, $y->{_e}, 10)
1406 if $y->{_es} eq '+' && !$MBI->_is_zero($y->{_e});
1408 # if $y has digits after dot
1409 my $shifty = 0; # correct _e of $x by this
1410 if ($y->{_es} eq '-') # has digits after dot
1412 # 123 % 2.5 => 1230 % 25 => 5 => 0.5
1413 $shifty = $MBI->_num($y->{_e}); # no more digits after dot
1414 $MBI->_lsft($x->{_m}, $y->{_e}, 10);# 123 => 1230, $y->{_m} is already 25
1416 # $ym is now mantissa of $y based on exponent 0
1418 my $shiftx = 0; # correct _e of $x by this
1419 if ($x->{_es} eq '-') # has digits after dot
1421 # 123.4 % 20 => 1234 % 200
1422 $shiftx = $MBI->_num($x->{_e}); # no more digits after dot
1423 $MBI->_lsft($ym, $x->{_e}, 10); # 123 => 1230
1425 # 123e1 % 20 => 1230 % 20
1426 if ($x->{_es} eq '+' && !$MBI->_is_zero($x->{_e}))
1428 $MBI->_lsft( $x->{_m}, $x->{_e},10); # es => '+' here
1431 $x->{_e} = $MBI->_new($shiftx);
1433 $x->{_es} = '-' if $shiftx != 0 || $shifty != 0;
1434 $MBI->_add( $x->{_e}, $MBI->_new($shifty)) if $shifty != 0;
1436 # now mantissas are equalized, exponent of $x is adjusted, so calc result
1438 $x->{_m} = $MBI->_mod( $x->{_m}, $ym);
1440 $x->{sign} = '+' if $MBI->_is_zero($x->{_m}); # fix sign for -0
1443 if ($neg != 0) # one of them negative => correct in place
1446 $x->{_m} = $r->{_m};
1447 $x->{_e} = $r->{_e};
1448 $x->{_es} = $r->{_es};
1449 $x->{sign} = '+' if $MBI->_is_zero($x->{_m}); # fix sign for -0
1453 $x->round($a,$p,$r,$y); # round and return
1458 # calculate $y'th root of $x
1461 my ($self,$x,$y,$a,$p,$r) = (ref($_[0]),@_);
1462 # objectify is costly, so avoid it
1463 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1465 ($self,$x,$y,$a,$p,$r) = objectify(2,@_);
1468 # NaN handling: $x ** 1/0, x or y NaN, or y inf/-inf or y == 0
1469 return $x->bnan() if $x->{sign} !~ /^\+/ || $y->is_zero() ||
1470 $y->{sign} !~ /^\+$/;
1472 return $x if $x->is_zero() || $x->is_one() || $x->is_inf() || $y->is_one();
1474 # we need to limit the accuracy to protect against overflow
1476 my (@params,$scale);
1477 ($x,@params) = $x->_find_round_parameters($a,$p,$r);
1479 return $x if $x->is_nan(); # error in _find_round_parameters?
1481 # no rounding at all, so must use fallback
1482 if (scalar @params == 0)
1484 # simulate old behaviour
1485 $params[0] = $self->div_scale(); # and round to it as accuracy
1486 $scale = $params[0]+4; # at least four more for proper round
1487 $params[2] = $r; # iound mode by caller or undef
1488 $fallback = 1; # to clear a/p afterwards
1492 # the 4 below is empirical, and there might be cases where it is not
1494 $scale = abs($params[0] || $params[1]) + 4; # take whatever is defined
1497 # when user set globals, they would interfere with our calculation, so
1498 # disable them and later re-enable them
1500 my $abr = "$self\::accuracy"; my $ab = $$abr; $$abr = undef;
1501 my $pbr = "$self\::precision"; my $pb = $$pbr; $$pbr = undef;
1502 # we also need to disable any set A or P on $x (_find_round_parameters took
1503 # them already into account), since these would interfere, too
1504 delete $x->{_a}; delete $x->{_p};
1505 # need to disable $upgrade in BigInt, to avoid deep recursion
1506 local $Math::BigInt::upgrade = undef; # should be really parent class vs MBI
1508 # remember sign and make $x positive, since -4 ** (1/2) => -2
1509 my $sign = 0; $sign = 1 if $x->{sign} eq '-'; $x->babs();
1511 if ($y->bcmp(2) == 0) # normal square root
1513 $x->bsqrt($scale+4);
1515 elsif ($y->is_one('-'))
1518 my $u = $self->bone()->bdiv($x,$scale);
1519 # copy private parts over
1520 $x->{_m} = $u->{_m};
1521 $x->{_e} = $u->{_e};
1522 $x->{_es} = $u->{_es};
1526 # calculate the broot() as integer result first, and if it fits, return
1527 # it rightaway (but only if $x and $y are integer):
1529 my $done = 0; # not yet
1530 if ($y->is_int() && $x->is_int())
1532 my $i = $MBI->_copy( $x->{_m} );
1533 $MBI->_lsft( $i, $x->{_e}, 10 ) unless $MBI->_is_zero($x->{_e});
1534 my $int = Math::BigInt->bzero();
1536 $int->broot($y->as_number());
1538 if ($int->copy()->bpow($y) == $x)
1540 # found result, return it
1541 $x->{_m} = $int->{value};
1542 $x->{_e} = $MBI->_zero();
1550 my $u = $self->bone()->bdiv($y,$scale+4);
1551 delete $u->{_a}; delete $u->{_p}; # otherwise it conflicts
1552 $x->bpow($u,$scale+4); # el cheapo
1555 $x->bneg() if $sign == 1;
1557 # shortcut to not run through _find_round_parameters again
1558 if (defined $params[0])
1560 $x->bround($params[0],$params[2]); # then round accordingly
1564 $x->bfround($params[1],$params[2]); # then round accordingly
1568 # clear a/p after round, since user did not request it
1569 delete $x->{_a}; delete $x->{_p};
1572 $$abr = $ab; $$pbr = $pb;
1578 # calculate square root
1579 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
1581 return $x->bnan() if $x->{sign} !~ /^[+]/; # NaN, -inf or < 0
1582 return $x if $x->{sign} eq '+inf'; # sqrt(inf) == inf
1583 return $x->round($a,$p,$r) if $x->is_zero() || $x->is_one();
1585 # we need to limit the accuracy to protect against overflow
1587 my (@params,$scale);
1588 ($x,@params) = $x->_find_round_parameters($a,$p,$r);
1590 return $x if $x->is_nan(); # error in _find_round_parameters?
1592 # no rounding at all, so must use fallback
1593 if (scalar @params == 0)
1595 # simulate old behaviour
1596 $params[0] = $self->div_scale(); # and round to it as accuracy
1597 $scale = $params[0]+4; # at least four more for proper round
1598 $params[2] = $r; # round mode by caller or undef
1599 $fallback = 1; # to clear a/p afterwards
1603 # the 4 below is empirical, and there might be cases where it is not
1605 $scale = abs($params[0] || $params[1]) + 4; # take whatever is defined
1608 # when user set globals, they would interfere with our calculation, so
1609 # disable them and later re-enable them
1611 my $abr = "$self\::accuracy"; my $ab = $$abr; $$abr = undef;
1612 my $pbr = "$self\::precision"; my $pb = $$pbr; $$pbr = undef;
1613 # we also need to disable any set A or P on $x (_find_round_parameters took
1614 # them already into account), since these would interfere, too
1615 delete $x->{_a}; delete $x->{_p};
1616 # need to disable $upgrade in BigInt, to avoid deep recursion
1617 local $Math::BigInt::upgrade = undef; # should be really parent class vs MBI
1619 my $i = $MBI->_copy( $x->{_m} );
1620 $MBI->_lsft( $i, $x->{_e}, 10 ) unless $MBI->_is_zero($x->{_e});
1621 my $xas = Math::BigInt->bzero();
1624 my $gs = $xas->copy()->bsqrt(); # some guess
1626 if (($x->{_es} ne '-') # guess can't be accurate if there are
1627 # digits after the dot
1628 && ($xas->bacmp($gs * $gs) == 0)) # guess hit the nail on the head?
1630 # exact result, copy result over to keep $x
1631 $x->{_m} = $gs->{value}; $x->{_e} = $MBI->_zero(); $x->{_es} = '+';
1633 # shortcut to not run through _find_round_parameters again
1634 if (defined $params[0])
1636 $x->bround($params[0],$params[2]); # then round accordingly
1640 $x->bfround($params[1],$params[2]); # then round accordingly
1644 # clear a/p after round, since user did not request it
1645 delete $x->{_a}; delete $x->{_p};
1647 # re-enable A and P, upgrade is taken care of by "local"
1648 ${"$self\::accuracy"} = $ab; ${"$self\::precision"} = $pb;
1652 # sqrt(2) = 1.4 because sqrt(2*100) = 1.4*10; so we can increase the accuracy
1653 # of the result by multipyling the input by 100 and then divide the integer
1654 # result of sqrt(input) by 10. Rounding afterwards returns the real result.
1656 # The following steps will transform 123.456 (in $x) into 123456 (in $y1)
1657 my $y1 = $MBI->_copy($x->{_m});
1659 my $length = $MBI->_len($y1);
1661 # Now calculate how many digits the result of sqrt(y1) would have
1662 my $digits = int($length / 2);
1664 # But we need at least $scale digits, so calculate how many are missing
1665 my $shift = $scale - $digits;
1667 # That should never happen (we take care of integer guesses above)
1668 # $shift = 0 if $shift < 0;
1670 # Multiply in steps of 100, by shifting left two times the "missing" digits
1671 my $s2 = $shift * 2;
1673 # We now make sure that $y1 has the same odd or even number of digits than
1674 # $x had. So when _e of $x is odd, we must shift $y1 by one digit left,
1675 # because we always must multiply by steps of 100 (sqrt(100) is 10) and not
1676 # steps of 10. The length of $x does not count, since an even or odd number
1677 # of digits before the dot is not changed by adding an even number of digits
1678 # after the dot (the result is still odd or even digits long).
1679 $s2++ if $MBI->_is_odd($x->{_e});
1681 $MBI->_lsft( $y1, $MBI->_new($s2), 10);
1683 # now take the square root and truncate to integer
1684 $y1 = $MBI->_sqrt($y1);
1686 # By "shifting" $y1 right (by creating a negative _e) we calculate the final
1687 # result, which is than later rounded to the desired scale.
1689 # calculate how many zeros $x had after the '.' (or before it, depending
1690 # on sign of $dat, the result should have half as many:
1691 my $dat = $MBI->_num($x->{_e});
1692 $dat = -$dat if $x->{_es} eq '-';
1697 # no zeros after the dot (e.g. 1.23, 0.49 etc)
1698 # preserve half as many digits before the dot than the input had
1699 # (but round this "up")
1700 $dat = int(($dat+1)/2);
1704 $dat = int(($dat)/2);
1706 $dat -= $MBI->_len($y1);
1710 $x->{_e} = $MBI->_new( $dat );
1715 $x->{_e} = $MBI->_new( $dat );
1721 # shortcut to not run through _find_round_parameters again
1722 if (defined $params[0])
1724 $x->bround($params[0],$params[2]); # then round accordingly
1728 $x->bfround($params[1],$params[2]); # then round accordingly
1732 # clear a/p after round, since user did not request it
1733 delete $x->{_a}; delete $x->{_p};
1736 $$abr = $ab; $$pbr = $pb;
1742 # (BFLOAT or num_str, BFLOAT or num_str) return BFLOAT
1743 # compute factorial number, modifies first argument
1746 my ($self,$x,@r) = (ref($_[0]),@_);
1747 # objectify is costly, so avoid it
1748 ($self,$x,@r) = objectify(1,@_) if !ref($x);
1750 return $x if $x->{sign} eq '+inf'; # inf => inf
1752 if (($x->{sign} ne '+') || # inf, NaN, <0 etc => NaN
1753 ($x->{_es} ne '+')); # digits after dot?
1755 # use BigInt's bfac() for faster calc
1756 if (! $MBI->_is_zero($x->{_e}))
1758 $MBI->_lsft($x->{_m}, $x->{_e},10); # change 12e1 to 120e0
1759 $x->{_e} = $MBI->_zero(); # normalize
1762 $MBI->_fac($x->{_m}); # calculate factorial
1763 $x->bnorm()->round(@r); # norm again and round result
1768 # Calculate a power where $y is a non-integer, like 2 ** 0.5
1769 my ($x,$y,$a,$p,$r) = @_;
1772 # if $y == 0.5, it is sqrt($x)
1773 return $x->bsqrt($a,$p,$r,$y) if $y->bcmp('0.5') == 0;
1776 # a ** x == e ** (x * ln a)
1780 # Taylor: | u u^2 u^3 |
1781 # x ** y = 1 + | --- + --- + ----- + ... |
1784 # we need to limit the accuracy to protect against overflow
1786 my ($scale,@params);
1787 ($x,@params) = $x->_find_round_parameters($a,$p,$r);
1789 return $x if $x->is_nan(); # error in _find_round_parameters?
1791 # no rounding at all, so must use fallback
1792 if (scalar @params == 0)
1794 # simulate old behaviour
1795 $params[0] = $self->div_scale(); # and round to it as accuracy
1796 $params[1] = undef; # disable P
1797 $scale = $params[0]+4; # at least four more for proper round
1798 $params[2] = $r; # round mode by caller or undef
1799 $fallback = 1; # to clear a/p afterwards
1803 # the 4 below is empirical, and there might be cases where it is not
1805 $scale = abs($params[0] || $params[1]) + 4; # take whatever is defined
1808 # when user set globals, they would interfere with our calculation, so
1809 # disable them and later re-enable them
1811 my $abr = "$self\::accuracy"; my $ab = $$abr; $$abr = undef;
1812 my $pbr = "$self\::precision"; my $pb = $$pbr; $$pbr = undef;
1813 # we also need to disable any set A or P on $x (_find_round_parameters took
1814 # them already into account), since these would interfere, too
1815 delete $x->{_a}; delete $x->{_p};
1816 # need to disable $upgrade in BigInt, to avoid deep recursion
1817 local $Math::BigInt::upgrade = undef;
1819 my ($limit,$v,$u,$below,$factor,$next,$over);
1821 $u = $x->copy()->blog(undef,$scale)->bmul($y);
1822 $v = $self->bone(); # 1
1823 $factor = $self->new(2); # 2
1824 $x->bone(); # first term: 1
1826 $below = $v->copy();
1829 $limit = $self->new("1E-". ($scale-1));
1833 # we calculate the next term, and add it to the last
1834 # when the next term is below our limit, it won't affect the outcome
1835 # anymore, so we stop
1836 $next = $over->copy()->bdiv($below,$scale);
1837 last if $next->bacmp($limit) <= 0;
1839 # calculate things for the next term
1840 $over *= $u; $below *= $factor; $factor->binc();
1842 last if $x->{sign} !~ /^[-+]$/;
1847 # shortcut to not run through _find_round_parameters again
1848 if (defined $params[0])
1850 $x->bround($params[0],$params[2]); # then round accordingly
1854 $x->bfround($params[1],$params[2]); # then round accordingly
1858 # clear a/p after round, since user did not request it
1859 delete $x->{_a}; delete $x->{_p};
1862 $$abr = $ab; $$pbr = $pb;
1868 # (BFLOAT or num_str, BFLOAT or num_str) return BFLOAT
1869 # compute power of two numbers, second arg is used as integer
1870 # modifies first argument
1873 my ($self,$x,$y,$a,$p,$r) = (ref($_[0]),@_);
1874 # objectify is costly, so avoid it
1875 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
1877 ($self,$x,$y,$a,$p,$r) = objectify(2,@_);
1880 return $x if $x->{sign} =~ /^[+-]inf$/;
1881 return $x->bnan() if $x->{sign} eq $nan || $y->{sign} eq $nan;
1882 return $x->bone() if $y->is_zero();
1883 return $x if $x->is_one() || $y->is_one();
1885 return $x->_pow($y,$a,$p,$r) if !$y->is_int(); # non-integer power
1887 my $y1 = $y->as_number()->{value}; # make CALC
1890 if ($x->{sign} eq '-' && $MBI->_is_one($x->{_m}) && $MBI->_is_zero($x->{_e}))
1892 # if $x == -1 and odd/even y => +1/-1 because +-1 ^ (+-1) => +-1
1893 return $MBI->_is_odd($y1) ? $x : $x->babs(1);
1897 return $x->bone() if $y->is_zero();
1898 return $x if $y->{sign} eq '+'; # 0**y => 0 (if not y <= 0)
1899 # 0 ** -y => 1 / (0 ** y) => 1 / 0! (1 / 0 => +inf)
1904 $new_sign = $y->is_odd() ? '-' : '+' if ($x->{sign} ne '+');
1906 # calculate $x->{_m} ** $y and $x->{_e} * $y separately (faster)
1907 $x->{_m} = $MBI->_pow( $x->{_m}, $y1);
1908 $MBI->_mul ($x->{_e}, $y1);
1910 $x->{sign} = $new_sign;
1912 if ($y->{sign} eq '-')
1914 # modify $x in place!
1915 my $z = $x->copy(); $x->bzero()->binc();
1916 return $x->bdiv($z,$a,$p,$r); # round in one go (might ignore y's A!)
1918 $x->round($a,$p,$r,$y);
1921 ###############################################################################
1922 # rounding functions
1926 # precision: round to the $Nth digit left (+$n) or right (-$n) from the '.'
1927 # $n == 0 means round to integer
1928 # expects and returns normalized numbers!
1929 my $x = shift; my $self = ref($x) || $x; $x = $self->new(shift) if !ref($x);
1931 return $x if $x->modify('bfround');
1933 my ($scale,$mode) = $x->_scale_p($self->precision(),$self->round_mode(),@_);
1934 return $x if !defined $scale; # no-op
1936 # never round a 0, +-inf, NaN
1939 $x->{_p} = $scale if !defined $x->{_p} || $x->{_p} < $scale; # -3 < -2
1942 return $x if $x->{sign} !~ /^[+-]$/;
1944 # don't round if x already has lower precision
1945 return $x if (defined $x->{_p} && $x->{_p} < 0 && $scale < $x->{_p});
1947 $x->{_p} = $scale; # remember round in any case
1948 delete $x->{_a}; # and clear A
1951 # round right from the '.'
1953 return $x if $x->{_es} eq '+'; # e >= 0 => nothing to round
1955 $scale = -$scale; # positive for simplicity
1956 my $len = $MBI->_len($x->{_m}); # length of mantissa
1958 # the following poses a restriction on _e, but if _e is bigger than a
1959 # scalar, you got other problems (memory etc) anyway
1960 my $dad = -(0+ ($x->{_es}.$MBI->_num($x->{_e}))); # digits after dot
1961 my $zad = 0; # zeros after dot
1962 $zad = $dad - $len if (-$dad < -$len); # for 0.00..00xxx style
1964 # p rint "scale $scale dad $dad zad $zad len $len\n";
1965 # number bsstr len zad dad
1966 # 0.123 123e-3 3 0 3
1967 # 0.0123 123e-4 3 1 4
1970 # 1.2345 12345e-4 5 0 4
1972 # do not round after/right of the $dad
1973 return $x if $scale > $dad; # 0.123, scale >= 3 => exit
1975 # round to zero if rounding inside the $zad, but not for last zero like:
1976 # 0.0065, scale -2, round last '0' with following '65' (scale == zad case)
1977 return $x->bzero() if $scale < $zad;
1978 if ($scale == $zad) # for 0.006, scale -3 and trunc
1984 # adjust round-point to be inside mantissa
1987 $scale = $scale-$zad;
1991 my $dbd = $len - $dad; $dbd = 0 if $dbd < 0; # digits before dot
1992 $scale = $dbd+$scale;
1998 # round left from the '.'
2000 # 123 => 100 means length(123) = 3 - $scale (2) => 1
2002 my $dbt = $MBI->_len($x->{_m});
2004 my $dbd = $dbt + ($x->{_es} . $MBI->_num($x->{_e}));
2005 # should be the same, so treat it as this
2006 $scale = 1 if $scale == 0;
2007 # shortcut if already integer
2008 return $x if $scale == 1 && $dbt <= $dbd;
2009 # maximum digits before dot
2014 # not enough digits before dot, so round to zero
2017 elsif ( $scale == $dbd )
2024 $scale = $dbd - $scale;
2027 # pass sign to bround for rounding modes '+inf' and '-inf'
2028 my $m = Math::BigInt->new( $x->{sign} . $MBI->_str($x->{_m}));
2029 $m->bround($scale,$mode);
2030 $x->{_m} = $m->{value}; # get our mantissa back
2036 # accuracy: preserve $N digits, and overwrite the rest with 0's
2037 my $x = shift; my $self = ref($x) || $x; $x = $self->new(shift) if !ref($x);
2039 if (($_[0] || 0) < 0)
2041 require Carp; Carp::croak ('bround() needs positive accuracy');
2044 my ($scale,$mode) = $x->_scale_a($self->accuracy(),$self->round_mode(),@_);
2045 return $x if !defined $scale; # no-op
2047 return $x if $x->modify('bround');
2049 # scale is now either $x->{_a}, $accuracy, or the user parameter
2050 # test whether $x already has lower accuracy, do nothing in this case
2051 # but do round if the accuracy is the same, since a math operation might
2052 # want to round a number with A=5 to 5 digits afterwards again
2053 return $x if defined $_[0] && defined $x->{_a} && $x->{_a} < $_[0];
2055 # scale < 0 makes no sense
2056 # never round a +-inf, NaN
2057 return $x if ($scale < 0) || $x->{sign} !~ /^[+-]$/;
2059 # 1: $scale == 0 => keep all digits
2060 # 2: never round a 0
2061 # 3: if we should keep more digits than the mantissa has, do nothing
2062 if ($scale == 0 || $x->is_zero() || $MBI->_len($x->{_m}) <= $scale)
2064 $x->{_a} = $scale if !defined $x->{_a} || $x->{_a} > $scale;
2068 # pass sign to bround for '+inf' and '-inf' rounding modes
2069 my $m = Math::BigInt->new( $x->{sign} . $MBI->_str($x->{_m}));
2071 $m->bround($scale,$mode); # round mantissa
2072 $x->{_m} = $m->{value}; # get our mantissa back
2073 $x->{_a} = $scale; # remember rounding
2074 delete $x->{_p}; # and clear P
2075 $x->bnorm(); # del trailing zeros gen. by bround()
2080 # return integer less or equal then $x
2081 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
2083 return $x if $x->modify('bfloor');
2085 return $x if $x->{sign} !~ /^[+-]$/; # nan, +inf, -inf
2087 # if $x has digits after dot
2088 if ($x->{_es} eq '-')
2090 $x->{_m} = $MBI->_rsft($x->{_m},$x->{_e},10); # cut off digits after dot
2091 $x->{_e} = $MBI->_zero(); # trunc/norm
2092 $x->{_es} = '+'; # abs e
2093 $MBI->_inc($x->{_m}) if $x->{sign} eq '-'; # increment if negative
2095 $x->round($a,$p,$r);
2100 # return integer greater or equal then $x
2101 my ($self,$x,$a,$p,$r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_);
2103 return $x if $x->modify('bceil');
2104 return $x if $x->{sign} !~ /^[+-]$/; # nan, +inf, -inf
2106 # if $x has digits after dot
2107 if ($x->{_es} eq '-')
2109 $x->{_m} = $MBI->_rsft($x->{_m},$x->{_e},10); # cut off digits after dot
2110 $x->{_e} = $MBI->_zero(); # trunc/norm
2111 $x->{_es} = '+'; # abs e
2112 $MBI->_inc($x->{_m}) if $x->{sign} eq '+'; # increment if positive
2114 $x->round($a,$p,$r);
2119 # shift right by $y (divide by power of $n)
2122 my ($self,$x,$y,$n,$a,$p,$r) = (ref($_[0]),@_);
2123 # objectify is costly, so avoid it
2124 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
2126 ($self,$x,$y,$n,$a,$p,$r) = objectify(2,@_);
2129 return $x if $x->modify('brsft');
2130 return $x if $x->{sign} !~ /^[+-]$/; # nan, +inf, -inf
2132 $n = 2 if !defined $n; $n = $self->new($n);
2133 $x->bdiv($n->bpow($y),$a,$p,$r,$y);
2138 # shift left by $y (multiply by power of $n)
2141 my ($self,$x,$y,$n,$a,$p,$r) = (ref($_[0]),@_);
2142 # objectify is costly, so avoid it
2143 if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1])))
2145 ($self,$x,$y,$n,$a,$p,$r) = objectify(2,@_);
2148 return $x if $x->modify('blsft');
2149 return $x if $x->{sign} !~ /^[+-]$/; # nan, +inf, -inf
2151 $n = 2 if !defined $n; $n = $self->new($n);
2152 $x->bmul($n->bpow($y),$a,$p,$r,$y);
2155 ###############################################################################
2159 # going through AUTOLOAD for every DESTROY is costly, avoid it by empty sub
2164 # make fxxx and bxxx both work by selectively mapping fxxx() to MBF::bxxx()
2165 # or falling back to MBI::bxxx()
2166 my $name = $AUTOLOAD;
2168 $name =~ s/(.*):://; # split package
2169 my $c = $1 || $class;
2171 $c->import() if $IMPORT == 0;
2172 if (!method_alias($name))
2176 # delayed load of Carp and avoid recursion
2178 Carp::croak ("$c: Can't call a method without name");
2180 if (!method_hand_up($name))
2182 # delayed load of Carp and avoid recursion
2184 Carp::croak ("Can't call $c\-\>$name, not a valid method");
2186 # try one level up, but subst. bxxx() for fxxx() since MBI only got bxxx()
2188 return &{"Math::BigInt"."::$name"}(@_);
2190 my $bname = $name; $bname =~ s/^f/b/;
2198 # return a copy of the exponent
2199 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2201 if ($x->{sign} !~ /^[+-]$/)
2203 my $s = $x->{sign}; $s =~ s/^[+-]//;
2204 return Math::BigInt->new($s); # -inf, +inf => +inf
2206 Math::BigInt->new( $x->{_es} . $MBI->_str($x->{_e}));
2211 # return a copy of the mantissa
2212 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2214 if ($x->{sign} !~ /^[+-]$/)
2216 my $s = $x->{sign}; $s =~ s/^[+]//;
2217 return Math::BigInt->new($s); # -inf, +inf => +inf
2219 my $m = Math::BigInt->new( $MBI->_str($x->{_m}));
2220 $m->bneg() if $x->{sign} eq '-';
2227 # return a copy of both the exponent and the mantissa
2228 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2230 if ($x->{sign} !~ /^[+-]$/)
2232 my $s = $x->{sign}; $s =~ s/^[+]//; my $se = $s; $se =~ s/^[-]//;
2233 return ($self->new($s),$self->new($se)); # +inf => inf and -inf,+inf => inf
2235 my $m = Math::BigInt->bzero();
2236 $m->{value} = $MBI->_copy($x->{_m});
2237 $m->bneg() if $x->{sign} eq '-';
2238 ($m, Math::BigInt->new( $x->{_es} . $MBI->_num($x->{_e}) ));
2241 ##############################################################################
2242 # private stuff (internal use only)
2248 my $lib = ''; my @a;
2250 for ( my $i = 0; $i < $l ; $i++)
2252 if ( $_[$i] eq ':constant' )
2254 # This causes overlord er load to step in. 'binary' and 'integer'
2255 # are handled by BigInt.
2256 overload::constant float => sub { $self->new(shift); };
2258 elsif ($_[$i] eq 'upgrade')
2260 # this causes upgrading
2261 $upgrade = $_[$i+1]; # or undef to disable
2264 elsif ($_[$i] eq 'downgrade')
2266 # this causes downgrading
2267 $downgrade = $_[$i+1]; # or undef to disable
2270 elsif ($_[$i] eq 'lib')
2272 # alternative library
2273 $lib = $_[$i+1] || ''; # default Calc
2276 elsif ($_[$i] eq 'with')
2278 # alternative class for our private parts()
2279 # XXX: no longer supported
2280 # $MBI = $_[$i+1] || 'Math::BigInt';
2289 # let use Math::BigInt lib => 'GMP'; use Math::BigFloat; still work
2290 my $mbilib = eval { Math::BigInt->config()->{lib} };
2291 if ((defined $mbilib) && ($MBI eq 'Math::BigInt::Calc'))
2293 # MBI already loaded
2294 Math::BigInt->import('lib',"$lib,$mbilib", 'objectify');
2298 # MBI not loaded, or with ne "Math::BigInt::Calc"
2299 $lib .= ",$mbilib" if defined $mbilib;
2300 $lib =~ s/^,//; # don't leave empty
2301 # replacement library can handle lib statement, but also could ignore it
2304 # Perl < 5.6.0 dies with "out of memory!" when eval() and ':constant' is
2305 # used in the same script, or eval inside import().
2306 require Math::BigInt;
2307 Math::BigInt->import( lib => $lib, 'objectify' );
2311 my $rc = "use Math::BigInt lib => '$lib', 'objectify';";
2317 require Carp; Carp::croak ("Couldn't load $lib: $! $@");
2319 $MBI = Math::BigInt->config()->{lib};
2321 # any non :constant stuff is handled by our parent, Exporter
2322 # even if @_ is empty, to give it a chance
2323 $self->SUPER::import(@a); # for subclasses
2324 $self->export_to_level(1,$self,@a); # need this, too
2329 # adjust m and e so that m is smallest possible
2330 # round number according to accuracy and precision settings
2331 my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_);
2333 return $x if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2335 my $zeros = $MBI->_zeros($x->{_m}); # correct for trailing zeros
2338 my $z = $MBI->_new($zeros);
2339 $x->{_m} = $MBI->_rsft ($x->{_m}, $z, 10);
2340 if ($x->{_es} eq '-')
2342 if ($MBI->_acmp($x->{_e},$z) >= 0)
2344 $x->{_e} = $MBI->_sub ($x->{_e}, $z);
2348 $x->{_e} = $MBI->_sub ( $MBI->_copy($z), $x->{_e});
2354 $x->{_e} = $MBI->_add ($x->{_e}, $z);
2359 # $x can only be 0Ey if there are no trailing zeros ('0' has 0 trailing
2360 # zeros). So, for something like 0Ey, set y to 1, and -0 => +0
2361 $x->{sign} = '+', $x->{_es} = '+', $x->{_e} = $MBI->_one()
2362 if $MBI->_is_zero($x->{_m});
2365 $x; # MBI bnorm is no-op, so dont call it
2368 ##############################################################################
2372 # return number as hexadecimal string (only for integers defined)
2373 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2375 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2376 return '0x0' if $x->is_zero();
2378 return $nan if $x->{_es} ne '+'; # how to do 1e-1 in hex!?
2380 my $z = $MBI->_copy($x->{_m});
2381 if (! $MBI->_is_zero($x->{_e})) # > 0
2383 $MBI->_lsft( $z, $x->{_e},10);
2385 $z = Math::BigInt->new( $x->{sign} . $MBI->_num($z));
2391 # return number as binary digit string (only for integers defined)
2392 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2394 return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, nan etc
2395 return '0b0' if $x->is_zero();
2397 return $nan if $x->{_es} ne '+'; # how to do 1e-1 in hex!?
2399 my $z = $MBI->_copy($x->{_m});
2400 if (! $MBI->_is_zero($x->{_e})) # > 0
2402 $MBI->_lsft( $z, $x->{_e},10);
2404 $z = Math::BigInt->new( $x->{sign} . $MBI->_num($z));
2410 # return copy as a bigint representation of this BigFloat number
2411 my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_);
2413 my $z = $MBI->_copy($x->{_m});
2414 if ($x->{_es} eq '-') # < 0
2416 $MBI->_rsft( $z, $x->{_e},10);
2418 elsif (! $MBI->_is_zero($x->{_e})) # > 0
2420 $MBI->_lsft( $z, $x->{_e},10);
2422 $z = Math::BigInt->new( $x->{sign} . $MBI->_num($z));
2429 my $class = ref($x) || $x;
2430 $x = $class->new(shift) unless ref($x);
2432 return 1 if $MBI->_is_zero($x->{_m});
2434 my $len = $MBI->_len($x->{_m});
2435 $len += $MBI->_num($x->{_e}) if $x->{_es} eq '+';
2439 $t = $MBI->_num($x->{_e}) if $x->{_es} eq '-';
2450 Math::BigFloat - Arbitrary size floating point math package
2457 $x = Math::BigFloat->new($str); # defaults to 0
2458 $nan = Math::BigFloat->bnan(); # create a NotANumber
2459 $zero = Math::BigFloat->bzero(); # create a +0
2460 $inf = Math::BigFloat->binf(); # create a +inf
2461 $inf = Math::BigFloat->binf('-'); # create a -inf
2462 $one = Math::BigFloat->bone(); # create a +1
2463 $one = Math::BigFloat->bone('-'); # create a -1
2466 $x->is_zero(); # true if arg is +0
2467 $x->is_nan(); # true if arg is NaN
2468 $x->is_one(); # true if arg is +1
2469 $x->is_one('-'); # true if arg is -1
2470 $x->is_odd(); # true if odd, false for even
2471 $x->is_even(); # true if even, false for odd
2472 $x->is_pos(); # true if >= 0
2473 $x->is_neg(); # true if < 0
2474 $x->is_inf(sign); # true if +inf, or -inf (default is '+')
2476 $x->bcmp($y); # compare numbers (undef,<0,=0,>0)
2477 $x->bacmp($y); # compare absolutely (undef,<0,=0,>0)
2478 $x->sign(); # return the sign, either +,- or NaN
2479 $x->digit($n); # return the nth digit, counting from right
2480 $x->digit(-$n); # return the nth digit, counting from left
2482 # The following all modify their first argument. If you want to preserve
2483 # $x, use $z = $x->copy()->bXXX($y); See under L<CAVEATS> for why this is
2484 # neccessary when mixing $a = $b assigments with non-overloaded math.
2487 $x->bzero(); # set $i to 0
2488 $x->bnan(); # set $i to NaN
2489 $x->bone(); # set $x to +1
2490 $x->bone('-'); # set $x to -1
2491 $x->binf(); # set $x to inf
2492 $x->binf('-'); # set $x to -inf
2494 $x->bneg(); # negation
2495 $x->babs(); # absolute value
2496 $x->bnorm(); # normalize (no-op)
2497 $x->bnot(); # two's complement (bit wise not)
2498 $x->binc(); # increment x by 1
2499 $x->bdec(); # decrement x by 1
2501 $x->badd($y); # addition (add $y to $x)
2502 $x->bsub($y); # subtraction (subtract $y from $x)
2503 $x->bmul($y); # multiplication (multiply $x by $y)
2504 $x->bdiv($y); # divide, set $x to quotient
2505 # return (quo,rem) or quo if scalar
2507 $x->bmod($y); # modulus ($x % $y)
2508 $x->bpow($y); # power of arguments ($x ** $y)
2509 $x->blsft($y); # left shift
2510 $x->brsft($y); # right shift
2511 # return (quo,rem) or quo if scalar
2513 $x->blog(); # logarithm of $x to base e (Euler's number)
2514 $x->blog($base); # logarithm of $x to base $base (f.i. 2)
2516 $x->band($y); # bit-wise and
2517 $x->bior($y); # bit-wise inclusive or
2518 $x->bxor($y); # bit-wise exclusive or
2519 $x->bnot(); # bit-wise not (two's complement)
2521 $x->bsqrt(); # calculate square-root
2522 $x->broot($y); # $y'th root of $x (e.g. $y == 3 => cubic root)
2523 $x->bfac(); # factorial of $x (1*2*3*4*..$x)
2525 $x->bround($N); # accuracy: preserve $N digits
2526 $x->bfround($N); # precision: round to the $Nth digit
2528 $x->bfloor(); # return integer less or equal than $x
2529 $x->bceil(); # return integer greater or equal than $x
2531 # The following do not modify their arguments:
2533 bgcd(@values); # greatest common divisor
2534 blcm(@values); # lowest common multiplicator
2536 $x->bstr(); # return string
2537 $x->bsstr(); # return string in scientific notation
2539 $x->as_int(); # return $x as BigInt
2540 $x->exponent(); # return exponent as BigInt
2541 $x->mantissa(); # return mantissa as BigInt
2542 $x->parts(); # return (mantissa,exponent) as BigInt
2544 $x->length(); # number of digits (w/o sign and '.')
2545 ($l,$f) = $x->length(); # number of digits, and length of fraction
2547 $x->precision(); # return P of $x (or global, if P of $x undef)
2548 $x->precision($n); # set P of $x to $n
2549 $x->accuracy(); # return A of $x (or global, if A of $x undef)
2550 $x->accuracy($n); # set A $x to $n
2552 # these get/set the appropriate global value for all BigFloat objects
2553 Math::BigFloat->precision(); # Precision
2554 Math::BigFloat->accuracy(); # Accuracy
2555 Math::BigFloat->round_mode(); # rounding mode
2559 All operators (inlcuding basic math operations) are overloaded if you
2560 declare your big floating point numbers as
2562 $i = new Math::BigFloat '12_3.456_789_123_456_789E-2';
2564 Operations with overloaded operators preserve the arguments, which is
2565 exactly what you expect.
2567 =head2 Canonical notation
2569 Input to these routines are either BigFloat objects, or strings of the
2570 following four forms:
2584 C</^[+-]\d+E[+-]?\d+$/>
2588 C</^[+-]\d*\.\d+E[+-]?\d+$/>
2592 all with optional leading and trailing zeros and/or spaces. Additonally,
2593 numbers are allowed to have an underscore between any two digits.
2595 Empty strings as well as other illegal numbers results in 'NaN'.
2597 bnorm() on a BigFloat object is now effectively a no-op, since the numbers
2598 are always stored in normalized form. On a string, it creates a BigFloat
2603 Output values are BigFloat objects (normalized), except for bstr() and bsstr().
2605 The string output will always have leading and trailing zeros stripped and drop
2606 a plus sign. C<bstr()> will give you always the form with a decimal point,
2607 while C<bsstr()> (s for scientific) gives you the scientific notation.
2609 Input bstr() bsstr()
2611 ' -123 123 123' '-123123123' '-123123123E0'
2612 '00.0123' '0.0123' '123E-4'
2613 '123.45E-2' '1.2345' '12345E-4'
2614 '10E+3' '10000' '1E4'
2616 Some routines (C<is_odd()>, C<is_even()>, C<is_zero()>, C<is_one()>,
2617 C<is_nan()>) return true or false, while others (C<bcmp()>, C<bacmp()>)
2618 return either undef, <0, 0 or >0 and are suited for sort.
2620 Actual math is done by using the class defined with C<with => Class;> (which
2621 defaults to BigInts) to represent the mantissa and exponent.
2623 The sign C</^[+-]$/> is stored separately. The string 'NaN' is used to
2624 represent the result when input arguments are not numbers, as well as
2625 the result of dividing by zero.
2627 =head2 C<mantissa()>, C<exponent()> and C<parts()>
2629 C<mantissa()> and C<exponent()> return the said parts of the BigFloat
2630 as BigInts such that:
2632 $m = $x->mantissa();
2633 $e = $x->exponent();
2634 $y = $m * ( 10 ** $e );
2635 print "ok\n" if $x == $y;
2637 C<< ($m,$e) = $x->parts(); >> is just a shortcut giving you both of them.
2639 A zero is represented and returned as C<0E1>, B<not> C<0E0> (after Knuth).
2641 Currently the mantissa is reduced as much as possible, favouring higher
2642 exponents over lower ones (e.g. returning 1e7 instead of 10e6 or 10000000e0).
2643 This might change in the future, so do not depend on it.
2645 =head2 Accuracy vs. Precision
2647 See also: L<Rounding|Rounding>.
2649 Math::BigFloat supports both precision and accuracy. For a full documentation,
2650 examples and tips on these topics please see the large section in
2653 Since things like sqrt(2) or 1/3 must presented with a limited precision lest
2654 a operation consumes all resources, each operation produces no more than
2655 the requested number of digits.
2657 Please refer to BigInt's documentation for the precedence rules of which
2658 accuracy/precision setting will be used.
2660 If there is no gloabl precision set, B<and> the operation inquestion was not
2661 called with a requested precision or accuracy, B<and> the input $x has no
2662 accuracy or precision set, then a fallback parameter will be used. For
2663 historical reasons, it is called C<div_scale> and can be accessed via:
2665 $d = Math::BigFloat->div_scale(); # query
2666 Math::BigFloat->div_scale($n); # set to $n digits
2668 The default value is 40 digits.
2670 In case the result of one operation has more precision than specified,
2671 it is rounded. The rounding mode taken is either the default mode, or the one
2672 supplied to the operation after the I<scale>:
2674 $x = Math::BigFloat->new(2);
2675 Math::BigFloat->precision(5); # 5 digits max
2676 $y = $x->copy()->bdiv(3); # will give 0.66666
2677 $y = $x->copy()->bdiv(3,6); # will give 0.666666
2678 $y = $x->copy()->bdiv(3,6,'odd'); # will give 0.666667
2679 Math::BigFloat->round_mode('zero');
2680 $y = $x->copy()->bdiv(3,6); # will give 0.666666
2686 =item ffround ( +$scale )
2688 Rounds to the $scale'th place left from the '.', counting from the dot.
2689 The first digit is numbered 1.
2691 =item ffround ( -$scale )
2693 Rounds to the $scale'th place right from the '.', counting from the dot.
2697 Rounds to an integer.
2699 =item fround ( +$scale )
2701 Preserves accuracy to $scale digits from the left (aka significant digits)
2702 and pads the rest with zeros. If the number is between 1 and -1, the
2703 significant digits count from the first non-zero after the '.'
2705 =item fround ( -$scale ) and fround ( 0 )
2707 These are effectively no-ops.
2711 All rounding functions take as a second parameter a rounding mode from one of
2712 the following: 'even', 'odd', '+inf', '-inf', 'zero' or 'trunc'.
2714 The default rounding mode is 'even'. By using
2715 C<< Math::BigFloat->round_mode($round_mode); >> you can get and set the default
2716 mode for subsequent rounding. The usage of C<$Math::BigFloat::$round_mode> is
2717 no longer supported.
2718 The second parameter to the round functions then overrides the default
2721 The C<as_number()> function returns a BigInt from a Math::BigFloat. It uses
2722 'trunc' as rounding mode to make it equivalent to:
2727 You can override this by passing the desired rounding mode as parameter to
2730 $x = Math::BigFloat->new(2.5);
2731 $y = $x->as_number('odd'); # $y = 3
2737 =head1 Autocreating constants
2739 After C<use Math::BigFloat ':constant'> all the floating point constants
2740 in the given scope are converted to C<Math::BigFloat>. This conversion
2741 happens at compile time.
2745 perl -MMath::BigFloat=:constant -e 'print 2E-100,"\n"'
2747 prints the value of C<2E-100>. Note that without conversion of
2748 constants the expression 2E-100 will be calculated as normal floating point
2751 Please note that ':constant' does not affect integer constants, nor binary
2752 nor hexadecimal constants. Use L<bignum> or L<Math::BigInt> to get this to
2757 Math with the numbers is done (by default) by a module called
2758 Math::BigInt::Calc. This is equivalent to saying:
2760 use Math::BigFloat lib => 'Calc';
2762 You can change this by using:
2764 use Math::BigFloat lib => 'BitVect';
2766 The following would first try to find Math::BigInt::Foo, then
2767 Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
2769 use Math::BigFloat lib => 'Foo,Math::BigInt::Bar';
2771 Calc.pm uses as internal format an array of elements of some decimal base
2772 (usually 1e7, but this might be differen for some systems) with the least
2773 significant digit first, while BitVect.pm uses a bit vector of base 2, most
2774 significant bit first. Other modules might use even different means of
2775 representing the numbers. See the respective module documentation for further
2778 Please note that Math::BigFloat does B<not> use the denoted library itself,
2779 but it merely passes the lib argument to Math::BigInt. So, instead of the need
2782 use Math::BigInt lib => 'GMP';
2785 you can roll it all into one line:
2787 use Math::BigFloat lib => 'GMP';
2789 It is also possible to just require Math::BigFloat:
2791 require Math::BigFloat;
2793 This will load the neccessary things (like BigInt) when they are needed, and
2796 Use the lib, Luke! And see L<Using Math::BigInt::Lite> for more details than
2797 you ever wanted to know about loading a different library.
2799 =head2 Using Math::BigInt::Lite
2801 It is possible to use L<Math::BigInt::Lite> with Math::BigFloat:
2804 use Math::BigFloat with => 'Math::BigInt::Lite';
2806 There is no need to "use Math::BigInt" or "use Math::BigInt::Lite", but you
2807 can combine these if you want. For instance, you may want to use
2808 Math::BigInt objects in your main script, too.
2812 use Math::BigFloat with => 'Math::BigInt::Lite';
2814 Of course, you can combine this with the C<lib> parameter.
2817 use Math::BigFloat with => 'Math::BigInt::Lite', lib => 'GMP,Pari';
2819 There is no need for a "use Math::BigInt;" statement, even if you want to
2820 use Math::BigInt's, since Math::BigFloat will needs Math::BigInt and thus
2821 always loads it. But if you add it, add it B<before>:
2825 use Math::BigFloat with => 'Math::BigInt::Lite', lib => 'GMP,Pari';
2827 Notice that the module with the last C<lib> will "win" and thus
2828 it's lib will be used if the lib is available:
2831 use Math::BigInt lib => 'Bar,Baz';
2832 use Math::BigFloat with => 'Math::BigInt::Lite', lib => 'Foo';
2834 That would try to load Foo, Bar, Baz and Calc (in that order). Or in other
2835 words, Math::BigFloat will try to retain previously loaded libs when you
2836 don't specify it onem but if you specify one, it will try to load them.
2838 Actually, the lib loading order would be "Bar,Baz,Calc", and then
2839 "Foo,Bar,Baz,Calc", but independend of which lib exists, the result is the
2840 same as trying the latter load alone, except for the fact that one of Bar or
2841 Baz might be loaded needlessly in an intermidiate step (and thus hang around
2842 and waste memory). If neither Bar nor Baz exist (or don't work/compile), they
2843 will still be tried to be loaded, but this is not as time/memory consuming as
2844 actually loading one of them. Still, this type of usage is not recommended due
2847 The old way (loading the lib only in BigInt) still works though:
2850 use Math::BigInt lib => 'Bar,Baz';
2853 You can even load Math::BigInt afterwards:
2857 use Math::BigInt lib => 'Bar,Baz';
2859 But this has the same problems like #5, it will first load Calc
2860 (Math::BigFloat needs Math::BigInt and thus loads it) and then later Bar or
2861 Baz, depending on which of them works and is usable/loadable. Since this
2862 loads Calc unnecc., it is not recommended.
2864 Since it also possible to just require Math::BigFloat, this poses the question
2865 about what libary this will use:
2867 require Math::BigFloat;
2868 my $x = Math::BigFloat->new(123); $x += 123;
2870 It will use Calc. Please note that the call to import() is still done, but
2871 only when you use for the first time some Math::BigFloat math (it is triggered
2872 via any constructor, so the first time you create a Math::BigFloat, the load
2873 will happen in the background). This means:
2875 require Math::BigFloat;
2876 Math::BigFloat->import ( lib => 'Foo,Bar' );
2878 would be the same as:
2880 use Math::BigFloat lib => 'Foo, Bar';
2882 But don't try to be clever to insert some operations in between:
2884 require Math::BigFloat;
2885 my $x = Math::BigFloat->bone() + 4; # load BigInt and Calc
2886 Math::BigFloat->import( lib => 'Pari' ); # load Pari, too
2887 $x = Math::BigFloat->bone()+4; # now use Pari
2889 While this works, it loads Calc needlessly. But maybe you just wanted that?
2891 B<Examples #3 is highly recommended> for daily usage.
2895 Please see the file BUGS in the CPAN distribution Math::BigInt for known bugs.
2901 =item stringify, bstr()
2903 Both stringify and bstr() now drop the leading '+'. The old code would return
2904 '+1.23', the new returns '1.23'. See the documentation in L<Math::BigInt> for
2905 reasoning and details.
2909 The following will probably not do what you expect:
2911 print $c->bdiv(123.456),"\n";
2913 It prints both quotient and reminder since print works in list context. Also,
2914 bdiv() will modify $c, so be carefull. You probably want to use
2916 print $c / 123.456,"\n";
2917 print scalar $c->bdiv(123.456),"\n"; # or if you want to modify $c
2921 =item Modifying and =
2925 $x = Math::BigFloat->new(5);
2928 It will not do what you think, e.g. making a copy of $x. Instead it just makes
2929 a second reference to the B<same> object and stores it in $y. Thus anything
2930 that modifies $x will modify $y (except overloaded math operators), and vice
2931 versa. See L<Math::BigInt> for details and how to avoid that.
2935 C<bpow()> now modifies the first argument, unlike the old code which left
2936 it alone and only returned the result. This is to be consistent with
2937 C<badd()> etc. The first will modify $x, the second one won't:
2939 print bpow($x,$i),"\n"; # modify $x
2940 print $x->bpow($i),"\n"; # ditto
2941 print $x ** $i,"\n"; # leave $x alone
2947 L<Math::BigInt>, L<Math::BigRat> and L<Math::Big> as well as
2948 L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>.
2950 The pragmas L<bignum>, L<bigint> and L<bigrat> might also be of interest
2951 because they solve the autoupgrading/downgrading issue, at least partly.
2954 L<http://search.cpan.org/search?mode=module&query=Math%3A%3ABigInt> contains
2955 more documentation including a full version history, testcases, empty
2956 subclass files and benchmarks.
2960 This program is free software; you may redistribute it and/or modify it under
2961 the same terms as Perl itself.
2965 Mark Biggar, overloaded interface by Ilya Zakharevich.
2966 Completely rewritten by Tels http://bloodgate.com in 2001, 2002, and still