diff options
Diffstat (limited to 'cpan/Math-BigRat/lib/Math/BigRat.pm')
| -rw-r--r-- | cpan/Math-BigRat/lib/Math/BigRat.pm | 2020 |
1 files changed, 2020 insertions, 0 deletions
diff --git a/cpan/Math-BigRat/lib/Math/BigRat.pm b/cpan/Math-BigRat/lib/Math/BigRat.pm new file mode 100644 index 0000000000..2460d1c7d4 --- /dev/null +++ b/cpan/Math-BigRat/lib/Math/BigRat.pm @@ -0,0 +1,2020 @@ + +# +# "Tax the rat farms." - Lord Vetinari +# + +# The following hash values are used: +# sign : +,-,NaN,+inf,-inf +# _d : denominator +# _n : numeraotr (value = _n/_d) +# _a : accuracy +# _p : precision +# You should not look at the innards of a BigRat - use the methods for this. + +package Math::BigRat; + +# anythig older is untested, and unlikely to work +use 5.006; +use strict; + +use Math::BigFloat; +use vars qw($VERSION @ISA $upgrade $downgrade + $accuracy $precision $round_mode $div_scale $_trap_nan $_trap_inf); + +@ISA = qw(Math::BigFloat); + +$VERSION = '0.24'; +$VERSION = eval $VERSION; + +use overload; # inherit overload from Math::BigFloat + +BEGIN + { + *objectify = \&Math::BigInt::objectify; # inherit this from BigInt + *AUTOLOAD = \&Math::BigFloat::AUTOLOAD; # can't inherit AUTOLOAD + # we inherit these from BigFloat because currently it is not possible + # that MBF has a different $MBI variable than we, because MBF also uses + # Math::BigInt::config->('lib'); (there is always only one library loaded) + *_e_add = \&Math::BigFloat::_e_add; + *_e_sub = \&Math::BigFloat::_e_sub; + *as_int = \&as_number; + *is_pos = \&is_positive; + *is_neg = \&is_negative; + } + +############################################################################## +# Global constants and flags. Access these only via the accessor methods! + +$accuracy = $precision = undef; +$round_mode = 'even'; +$div_scale = 40; +$upgrade = undef; +$downgrade = undef; + +# These are internally, and not to be used from the outside at all! + +$_trap_nan = 0; # are NaNs ok? set w/ config() +$_trap_inf = 0; # are infs ok? set w/ config() + +# the package we are using for our private parts, defaults to: +# Math::BigInt->config()->{lib} +my $MBI = 'Math::BigInt::Calc'; + +my $nan = 'NaN'; +my $class = 'Math::BigRat'; + +sub isa + { + return 0 if $_[1] =~ /^Math::Big(Int|Float)/; # we aren't + UNIVERSAL::isa(@_); + } + +############################################################################## + +sub _new_from_float + { + # turn a single float input into a rational number (like '0.1') + my ($self,$f) = @_; + + return $self->bnan() if $f->is_nan(); + return $self->binf($f->{sign}) if $f->{sign} =~ /^[+-]inf$/; + + $self->{_n} = $MBI->_copy( $f->{_m} ); # mantissa + $self->{_d} = $MBI->_one(); + $self->{sign} = $f->{sign} || '+'; + if ($f->{_es} eq '-') + { + # something like Math::BigRat->new('0.1'); + # 1 / 1 => 1/10 + $MBI->_lsft ( $self->{_d}, $f->{_e} ,10); + } + else + { + # something like Math::BigRat->new('10'); + # 1 / 1 => 10/1 + $MBI->_lsft ( $self->{_n}, $f->{_e} ,10) unless + $MBI->_is_zero($f->{_e}); + } + $self; + } + +sub new + { + # create a Math::BigRat + my $class = shift; + + my ($n,$d) = @_; + + my $self = { }; bless $self,$class; + + # input like (BigInt) or (BigFloat): + if ((!defined $d) && (ref $n) && (!$n->isa('Math::BigRat'))) + { + if ($n->isa('Math::BigFloat')) + { + $self->_new_from_float($n); + } + if ($n->isa('Math::BigInt')) + { + # TODO: trap NaN, inf + $self->{_n} = $MBI->_copy($n->{value}); # "mantissa" = N + $self->{_d} = $MBI->_one(); # d => 1 + $self->{sign} = $n->{sign}; + } + if ($n->isa('Math::BigInt::Lite')) + { + # TODO: trap NaN, inf + $self->{sign} = '+'; $self->{sign} = '-' if $$n < 0; + $self->{_n} = $MBI->_new(abs($$n)); # "mantissa" = N + $self->{_d} = $MBI->_one(); # d => 1 + } + return $self->bnorm(); # normalize (120/1 => 12/10) + } + + # input like (BigInt,BigInt) or (BigLite,BigLite): + if (ref($d) && ref($n)) + { + # do N first (for $self->{sign}): + if ($n->isa('Math::BigInt')) + { + # TODO: trap NaN, inf + $self->{_n} = $MBI->_copy($n->{value}); # "mantissa" = N + $self->{sign} = $n->{sign}; + } + elsif ($n->isa('Math::BigInt::Lite')) + { + # TODO: trap NaN, inf + $self->{sign} = '+'; $self->{sign} = '-' if $$n < 0; + $self->{_n} = $MBI->_new(abs($$n)); # "mantissa" = $n + } + else + { + require Carp; + Carp::croak(ref($n) . " is not a recognized object format for Math::BigRat->new"); + } + # now D: + if ($d->isa('Math::BigInt')) + { + # TODO: trap NaN, inf + $self->{_d} = $MBI->_copy($d->{value}); # "mantissa" = D + # +/+ or -/- => +, +/- or -/+ => - + $self->{sign} = $d->{sign} ne $self->{sign} ? '-' : '+'; + } + elsif ($d->isa('Math::BigInt::Lite')) + { + # TODO: trap NaN, inf + $self->{_d} = $MBI->_new(abs($$d)); # "mantissa" = D + my $ds = '+'; $ds = '-' if $$d < 0; + # +/+ or -/- => +, +/- or -/+ => - + $self->{sign} = $ds ne $self->{sign} ? '-' : '+'; + } + else + { + require Carp; + Carp::croak(ref($d) . " is not a recognized object format for Math::BigRat->new"); + } + return $self->bnorm(); # normalize (120/1 => 12/10) + } + return $n->copy() if ref $n; # already a BigRat + + if (!defined $n) + { + $self->{_n} = $MBI->_zero(); # undef => 0 + $self->{_d} = $MBI->_one(); + $self->{sign} = '+'; + return $self; + } + + # string input with / delimiter + if ($n =~ /\s*\/\s*/) + { + return $class->bnan() if $n =~ /\/.*\//; # 1/2/3 isn't valid + return $class->bnan() if $n =~ /\/\s*$/; # 1/ isn't valid + ($n,$d) = split (/\//,$n); + # try as BigFloats first + if (($n =~ /[\.eE]/) || ($d =~ /[\.eE]/)) + { + local $Math::BigFloat::accuracy = undef; + local $Math::BigFloat::precision = undef; + + # one of them looks like a float + my $nf = Math::BigFloat->new($n,undef,undef); + $self->{sign} = '+'; + return $self->bnan() if $nf->is_nan(); + + $self->{_n} = $MBI->_copy( $nf->{_m} ); # get mantissa + + # now correct $self->{_n} due to $n + my $f = Math::BigFloat->new($d,undef,undef); + return $self->bnan() if $f->is_nan(); + $self->{_d} = $MBI->_copy( $f->{_m} ); + + # calculate the difference between nE and dE + my $diff_e = $nf->exponent()->bsub( $f->exponent); + if ($diff_e->is_negative()) + { + # < 0: mul d with it + $MBI->_lsft( $self->{_d}, $MBI->_new( $diff_e->babs()), 10); + } + elsif (!$diff_e->is_zero()) + { + # > 0: mul n with it + $MBI->_lsft( $self->{_n}, $MBI->_new( $diff_e), 10); + } + } + else + { + # both d and n look like (big)ints + + $self->{sign} = '+'; # no sign => '+' + $self->{_n} = undef; + $self->{_d} = undef; + if ($n =~ /^([+-]?)0*([0-9]+)\z/) # first part ok? + { + $self->{sign} = $1 || '+'; # no sign => '+' + $self->{_n} = $MBI->_new($2 || 0); + } + + if ($d =~ /^([+-]?)0*([0-9]+)\z/) # second part ok? + { + $self->{sign} =~ tr/+-/-+/ if ($1 || '') eq '-'; # negate if second part neg. + $self->{_d} = $MBI->_new($2 || 0); + } + + if (!defined $self->{_n} || !defined $self->{_d}) + { + $d = Math::BigInt->new($d,undef,undef) unless ref $d; + $n = Math::BigInt->new($n,undef,undef) unless ref $n; + + if ($n->{sign} =~ /^[+-]$/ && $d->{sign} =~ /^[+-]$/) + { + # both parts are ok as integers (wierd things like ' 1e0' + $self->{_n} = $MBI->_copy($n->{value}); + $self->{_d} = $MBI->_copy($d->{value}); + $self->{sign} = $n->{sign}; + $self->{sign} =~ tr/+-/-+/ if $d->{sign} eq '-'; # -1/-2 => 1/2 + return $self->bnorm(); + } + + $self->{sign} = '+'; # a default sign + return $self->bnan() if $n->is_nan() || $d->is_nan(); + + # handle inf cases: + if ($n->is_inf() || $d->is_inf()) + { + if ($n->is_inf()) + { + return $self->bnan() if $d->is_inf(); # both are inf => NaN + my $s = '+'; # '+inf/+123' or '-inf/-123' + $s = '-' if substr($n->{sign},0,1) ne $d->{sign}; + # +-inf/123 => +-inf + return $self->binf($s); + } + # 123/inf => 0 + return $self->bzero(); + } + } + } + + return $self->bnorm(); + } + + # simple string input + if (($n =~ /[\.eE]/) && $n !~ /^0x/) + { + # looks like a float, quacks like a float, so probably is a float + $self->{sign} = 'NaN'; + local $Math::BigFloat::accuracy = undef; + local $Math::BigFloat::precision = undef; + $self->_new_from_float(Math::BigFloat->new($n,undef,undef)); + } + else + { + # for simple forms, use $MBI directly + if ($n =~ /^([+-]?)0*([0-9]+)\z/) + { + $self->{sign} = $1 || '+'; + $self->{_n} = $MBI->_new($2 || 0); + $self->{_d} = $MBI->_one(); + } + else + { + my $n = Math::BigInt->new($n,undef,undef); + $self->{_n} = $MBI->_copy($n->{value}); + $self->{_d} = $MBI->_one(); + $self->{sign} = $n->{sign}; + return $self->bnan() if $self->{sign} eq 'NaN'; + return $self->binf($self->{sign}) if $self->{sign} =~ /^[+-]inf$/; + } + } + $self->bnorm(); + } + +sub copy + { + # if two arguments, the first one is the class to "swallow" subclasses + my ($c,$x) = @_; + + if (scalar @_ == 1) + { + $x = $_[0]; + $c = ref($x); + } + return unless ref($x); # only for objects + + my $self = bless {}, $c; + + $self->{sign} = $x->{sign}; + $self->{_d} = $MBI->_copy($x->{_d}); + $self->{_n} = $MBI->_copy($x->{_n}); + $self->{_a} = $x->{_a} if defined $x->{_a}; + $self->{_p} = $x->{_p} if defined $x->{_p}; + $self; + } + +############################################################################## + +sub config + { + # return (later set?) configuration data as hash ref + my $class = shift || 'Math::BigRat'; + + if (@_ == 1 && ref($_[0]) ne 'HASH') + { + my $cfg = $class->SUPER::config(); + return $cfg->{$_[0]}; + } + + my $cfg = $class->SUPER::config(@_); + + # now we need only to override the ones that are different from our parent + $cfg->{class} = $class; + $cfg->{with} = $MBI; + $cfg; + } + +############################################################################## + +sub bstr + { + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + if ($x->{sign} !~ /^[+-]$/) # inf, NaN etc + { + my $s = $x->{sign}; $s =~ s/^\+//; # +inf => inf + return $s; + } + + my $s = ''; $s = $x->{sign} if $x->{sign} ne '+'; # '+3/2' => '3/2' + + return $s . $MBI->_str($x->{_n}) if $MBI->_is_one($x->{_d}); + $s . $MBI->_str($x->{_n}) . '/' . $MBI->_str($x->{_d}); + } + +sub bsstr + { + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + if ($x->{sign} !~ /^[+-]$/) # inf, NaN etc + { + my $s = $x->{sign}; $s =~ s/^\+//; # +inf => inf + return $s; + } + + my $s = ''; $s = $x->{sign} if $x->{sign} ne '+'; # +3 vs 3 + $s . $MBI->_str($x->{_n}) . '/' . $MBI->_str($x->{_d}); + } + +sub bnorm + { + # reduce the number to the shortest form + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + # Both parts must be objects of whatever we are using today. + if ( my $c = $MBI->_check($x->{_n}) ) + { + require Carp; Carp::croak ("n did not pass the self-check ($c) in bnorm()"); + } + if ( my $c = $MBI->_check($x->{_d}) ) + { + require Carp; Carp::croak ("d did not pass the self-check ($c) in bnorm()"); + } + + # no normalize for NaN, inf etc. + return $x if $x->{sign} !~ /^[+-]$/; + + # normalize zeros to 0/1 + if ($MBI->_is_zero($x->{_n})) + { + $x->{sign} = '+'; # never leave a -0 + $x->{_d} = $MBI->_one() unless $MBI->_is_one($x->{_d}); + return $x; + } + + return $x if $MBI->_is_one($x->{_d}); # no need to reduce + + # reduce other numbers + my $gcd = $MBI->_copy($x->{_n}); + $gcd = $MBI->_gcd($gcd,$x->{_d}); + + if (!$MBI->_is_one($gcd)) + { + $x->{_n} = $MBI->_div($x->{_n},$gcd); + $x->{_d} = $MBI->_div($x->{_d},$gcd); + } + $x; + } + +############################################################################## +# sign manipulation + +sub bneg + { + # (BRAT or num_str) return BRAT + # negate number or make a negated number from string + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + return $x if $x->modify('bneg'); + + # for +0 dont negate (to have always normalized +0). Does nothing for 'NaN' + $x->{sign} =~ tr/+-/-+/ unless ($x->{sign} eq '+' && $MBI->_is_zero($x->{_n})); + $x; + } + +############################################################################## +# special values + +sub _bnan + { + # used by parent class bnan() to initialize number to NaN + my $self = shift; + + if ($_trap_nan) + { + require Carp; + my $class = ref($self); + # "$self" below will stringify the object, this blows up if $self is a + # partial object (happens under trap_nan), so fix it beforehand + $self->{_d} = $MBI->_zero() unless defined $self->{_d}; + $self->{_n} = $MBI->_zero() unless defined $self->{_n}; + Carp::croak ("Tried to set $self to NaN in $class\::_bnan()"); + } + $self->{_n} = $MBI->_zero(); + $self->{_d} = $MBI->_zero(); + } + +sub _binf + { + # used by parent class bone() to initialize number to +inf/-inf + my $self = shift; + + if ($_trap_inf) + { + require Carp; + my $class = ref($self); + # "$self" below will stringify the object, this blows up if $self is a + # partial object (happens under trap_nan), so fix it beforehand + $self->{_d} = $MBI->_zero() unless defined $self->{_d}; + $self->{_n} = $MBI->_zero() unless defined $self->{_n}; + Carp::croak ("Tried to set $self to inf in $class\::_binf()"); + } + $self->{_n} = $MBI->_zero(); + $self->{_d} = $MBI->_zero(); + } + +sub _bone + { + # used by parent class bone() to initialize number to +1/-1 + my $self = shift; + $self->{_n} = $MBI->_one(); + $self->{_d} = $MBI->_one(); + } + +sub _bzero + { + # used by parent class bzero() to initialize number to 0 + my $self = shift; + $self->{_n} = $MBI->_zero(); + $self->{_d} = $MBI->_one(); + } + +############################################################################## +# mul/add/div etc + +sub badd + { + # add two rational numbers + + # set up parameters + my ($self,$x,$y,@r) = (ref($_[0]),@_); + # objectify is costly, so avoid it + if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1]))) + { + ($self,$x,$y,@r) = objectify(2,@_); + } + + # +inf + +inf => +inf, -inf + -inf => -inf + return $x->binf(substr($x->{sign},0,1)) + if $x->{sign} eq $y->{sign} && $x->{sign} =~ /^[+-]inf$/; + + # +inf + -inf or -inf + +inf => NaN + return $x->bnan() if ($x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/); + + # 1 1 gcd(3,4) = 1 1*3 + 1*4 7 + # - + - = --------- = -- + # 4 3 4*3 12 + + # we do not compute the gcd() here, but simple do: + # 5 7 5*3 + 7*4 43 + # - + - = --------- = -- + # 4 3 4*3 12 + + # and bnorm() will then take care of the rest + + # 5 * 3 + $x->{_n} = $MBI->_mul( $x->{_n}, $y->{_d}); + + # 7 * 4 + my $m = $MBI->_mul( $MBI->_copy( $y->{_n} ), $x->{_d} ); + + # 5 * 3 + 7 * 4 + ($x->{_n}, $x->{sign}) = _e_add( $x->{_n}, $m, $x->{sign}, $y->{sign}); + + # 4 * 3 + $x->{_d} = $MBI->_mul( $x->{_d}, $y->{_d}); + + # normalize result, and possible round + $x->bnorm()->round(@r); + } + +sub bsub + { + # subtract two rational numbers + + # set up parameters + my ($self,$x,$y,@r) = (ref($_[0]),@_); + # objectify is costly, so avoid it + if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1]))) + { + ($self,$x,$y,@r) = objectify(2,@_); + } + + # flip sign of $x, call badd(), then flip sign of result + $x->{sign} =~ tr/+-/-+/ + unless $x->{sign} eq '+' && $MBI->_is_zero($x->{_n}); # not -0 + $x->badd($y,@r); # does norm and round + $x->{sign} =~ tr/+-/-+/ + unless $x->{sign} eq '+' && $MBI->_is_zero($x->{_n}); # not -0 + $x; + } + +sub bmul + { + # multiply two rational numbers + + # set up parameters + my ($self,$x,$y,@r) = (ref($_[0]),@_); + # objectify is costly, so avoid it + if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1]))) + { + ($self,$x,$y,@r) = objectify(2,@_); + } + + return $x->bnan() if ($x->{sign} eq 'NaN' || $y->{sign} eq 'NaN'); + + # inf handling + if (($x->{sign} =~ /^[+-]inf$/) || ($y->{sign} =~ /^[+-]inf$/)) + { + return $x->bnan() if $x->is_zero() || $y->is_zero(); + # result will always be +-inf: + # +inf * +/+inf => +inf, -inf * -/-inf => +inf + # +inf * -/-inf => -inf, -inf * +/+inf => -inf + return $x->binf() if ($x->{sign} =~ /^\+/ && $y->{sign} =~ /^\+/); + return $x->binf() if ($x->{sign} =~ /^-/ && $y->{sign} =~ /^-/); + return $x->binf('-'); + } + + # x== 0 # also: or y == 1 or y == -1 + return wantarray ? ($x,$self->bzero()) : $x if $x->is_zero(); + + # XXX TODO: + # According to Knuth, this can be optimized by doing gcd twice (for d and n) + # and reducing in one step. This would save us the bnorm() at the end. + + # 1 2 1 * 2 2 1 + # - * - = ----- = - = - + # 4 3 4 * 3 12 6 + + $x->{_n} = $MBI->_mul( $x->{_n}, $y->{_n}); + $x->{_d} = $MBI->_mul( $x->{_d}, $y->{_d}); + + # compute new sign + $x->{sign} = $x->{sign} eq $y->{sign} ? '+' : '-'; + + $x->bnorm()->round(@r); + } + +sub bdiv + { + # (dividend: BRAT or num_str, divisor: BRAT or num_str) return + # (BRAT,BRAT) (quo,rem) or BRAT (only rem) + + # set up parameters + my ($self,$x,$y,@r) = (ref($_[0]),@_); + # objectify is costly, so avoid it + if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1]))) + { + ($self,$x,$y,@r) = objectify(2,@_); + } + + return $self->_div_inf($x,$y) + if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero()); + + # x== 0 # also: or y == 1 or y == -1 + return wantarray ? ($x,$self->bzero()) : $x if $x->is_zero(); + + # XXX TODO: list context, upgrade + # According to Knuth, this can be optimized by doing gcd twice (for d and n) + # and reducing in one step. This would save us the bnorm() at the end. + + # 1 1 1 3 + # - / - == - * - + # 4 3 4 1 + + $x->{_n} = $MBI->_mul( $x->{_n}, $y->{_d}); + $x->{_d} = $MBI->_mul( $x->{_d}, $y->{_n}); + + # compute new sign + $x->{sign} = $x->{sign} eq $y->{sign} ? '+' : '-'; + + $x->bnorm()->round(@r); + $x; + } + +sub bmod + { + # compute "remainder" (in Perl way) of $x / $y + + # set up parameters + my ($self,$x,$y,@r) = (ref($_[0]),@_); + # objectify is costly, so avoid it + if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1]))) + { + ($self,$x,$y,@r) = objectify(2,@_); + } + + return $self->_div_inf($x,$y) + if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/) || $y->is_zero()); + + return $x if $x->is_zero(); # 0 / 7 = 0, mod 0 + + # compute $x - $y * floor($x/$y), keeping the sign of $x + + # copy x to u, make it positive and then do a normal division ($u/$y) + my $u = bless { sign => '+' }, $self; + $u->{_n} = $MBI->_mul( $MBI->_copy($x->{_n}), $y->{_d} ); + $u->{_d} = $MBI->_mul( $MBI->_copy($x->{_d}), $y->{_n} ); + + # compute floor(u) + if (! $MBI->_is_one($u->{_d})) + { + $u->{_n} = $MBI->_div($u->{_n},$u->{_d}); # 22/7 => 3/1 w/ truncate + # no need to set $u->{_d} to 1, since below we set it to $y->{_d} anyway + } + + # now compute $y * $u + $u->{_d} = $MBI->_copy($y->{_d}); # 1 * $y->{_d}, see floor above + $u->{_n} = $MBI->_mul($u->{_n},$y->{_n}); + + my $xsign = $x->{sign}; $x->{sign} = '+'; # remember sign and make x positive + # compute $x - $u + $x->bsub($u); + $x->{sign} = $xsign; # put sign back + + $x->bnorm()->round(@r); + } + +############################################################################## +# bdec/binc + +sub bdec + { + # decrement value (subtract 1) + my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_); + + return $x if $x->{sign} !~ /^[+-]$/; # NaN, inf, -inf + + if ($x->{sign} eq '-') + { + $x->{_n} = $MBI->_add( $x->{_n}, $x->{_d}); # -5/2 => -7/2 + } + else + { + if ($MBI->_acmp($x->{_n},$x->{_d}) < 0) # n < d? + { + # 1/3 -- => -2/3 + $x->{_n} = $MBI->_sub( $MBI->_copy($x->{_d}), $x->{_n}); + $x->{sign} = '-'; + } + else + { + $x->{_n} = $MBI->_sub($x->{_n}, $x->{_d}); # 5/2 => 3/2 + } + } + $x->bnorm()->round(@r); + } + +sub binc + { + # increment value (add 1) + my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_); + + return $x if $x->{sign} !~ /^[+-]$/; # NaN, inf, -inf + + if ($x->{sign} eq '-') + { + if ($MBI->_acmp($x->{_n},$x->{_d}) < 0) + { + # -1/3 ++ => 2/3 (overflow at 0) + $x->{_n} = $MBI->_sub( $MBI->_copy($x->{_d}), $x->{_n}); + $x->{sign} = '+'; + } + else + { + $x->{_n} = $MBI->_sub($x->{_n}, $x->{_d}); # -5/2 => -3/2 + } + } + else + { + $x->{_n} = $MBI->_add($x->{_n},$x->{_d}); # 5/2 => 7/2 + } + $x->bnorm()->round(@r); + } + +############################################################################## +# is_foo methods (the rest is inherited) + +sub is_int + { + # return true if arg (BRAT or num_str) is an integer + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + return 1 if ($x->{sign} =~ /^[+-]$/) && # NaN and +-inf aren't + $MBI->_is_one($x->{_d}); # x/y && y != 1 => no integer + 0; + } + +sub is_zero + { + # return true if arg (BRAT or num_str) is zero + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + return 1 if $x->{sign} eq '+' && $MBI->_is_zero($x->{_n}); + 0; + } + +sub is_one + { + # return true if arg (BRAT or num_str) is +1 or -1 if signis given + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + my $sign = $_[2] || ''; $sign = '+' if $sign ne '-'; + return 1 + if ($x->{sign} eq $sign && $MBI->_is_one($x->{_n}) && $MBI->_is_one($x->{_d})); + 0; + } + +sub is_odd + { + # return true if arg (BFLOAT or num_str) is odd or false if even + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + return 1 if ($x->{sign} =~ /^[+-]$/) && # NaN & +-inf aren't + ($MBI->_is_one($x->{_d}) && $MBI->_is_odd($x->{_n})); # x/2 is not, but 3/1 + 0; + } + +sub is_even + { + # return true if arg (BINT or num_str) is even or false if odd + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + return 0 if $x->{sign} !~ /^[+-]$/; # NaN & +-inf aren't + return 1 if ($MBI->_is_one($x->{_d}) # x/3 is never + && $MBI->_is_even($x->{_n})); # but 4/1 is + 0; + } + +############################################################################## +# parts() and friends + +sub numerator + { + my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_); + + # NaN, inf, -inf + return Math::BigInt->new($x->{sign}) if ($x->{sign} !~ /^[+-]$/); + + my $n = Math::BigInt->new($MBI->_str($x->{_n})); $n->{sign} = $x->{sign}; + $n; + } + +sub denominator + { + my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_); + + # NaN + return Math::BigInt->new($x->{sign}) if $x->{sign} eq 'NaN'; + # inf, -inf + return Math::BigInt->bone() if $x->{sign} !~ /^[+-]$/; + + Math::BigInt->new($MBI->_str($x->{_d})); + } + +sub parts + { + my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_); + + my $c = 'Math::BigInt'; + + return ($c->bnan(),$c->bnan()) if $x->{sign} eq 'NaN'; + return ($c->binf(),$c->binf()) if $x->{sign} eq '+inf'; + return ($c->binf('-'),$c->binf()) if $x->{sign} eq '-inf'; + + my $n = $c->new( $MBI->_str($x->{_n})); + $n->{sign} = $x->{sign}; + my $d = $c->new( $MBI->_str($x->{_d})); + ($n,$d); + } + +sub length + { + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + return $nan unless $x->is_int(); + $MBI->_len($x->{_n}); # length(-123/1) => length(123) + } + +sub digit + { + my ($self,$x,$n) = ref($_[0]) ? (undef,$_[0],$_[1]) : objectify(1,@_); + + return $nan unless $x->is_int(); + $MBI->_digit($x->{_n},$n || 0); # digit(-123/1,2) => digit(123,2) + } + +############################################################################## +# special calc routines + +sub bceil + { + my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_); + + return $x if $x->{sign} !~ /^[+-]$/ || # not for NaN, inf + $MBI->_is_one($x->{_d}); # 22/1 => 22, 0/1 => 0 + + $x->{_n} = $MBI->_div($x->{_n},$x->{_d}); # 22/7 => 3/1 w/ truncate + $x->{_d} = $MBI->_one(); # d => 1 + $x->{_n} = $MBI->_inc($x->{_n}) + if $x->{sign} eq '+'; # +22/7 => 4/1 + $x->{sign} = '+' if $MBI->_is_zero($x->{_n}); # -0 => 0 + $x; + } + +sub bfloor + { + my ($self,$x) = ref($_[0]) ? (ref($_[0]),$_[0]) : objectify(1,@_); + + return $x if $x->{sign} !~ /^[+-]$/ || # not for NaN, inf + $MBI->_is_one($x->{_d}); # 22/1 => 22, 0/1 => 0 + + $x->{_n} = $MBI->_div($x->{_n},$x->{_d}); # 22/7 => 3/1 w/ truncate + $x->{_d} = $MBI->_one(); # d => 1 + $x->{_n} = $MBI->_inc($x->{_n}) + if $x->{sign} eq '-'; # -22/7 => -4/1 + $x; + } + +sub bfac + { + my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_); + + # if $x is not an integer + if (($x->{sign} ne '+') || (!$MBI->_is_one($x->{_d}))) + { + return $x->bnan(); + } + + $x->{_n} = $MBI->_fac($x->{_n}); + # since _d is 1, we don't need to reduce/norm the result + $x->round(@r); + } + +sub bpow + { + # power ($x ** $y) + + # set up parameters + my ($self,$x,$y,@r) = (ref($_[0]),@_); + # objectify is costly, so avoid it + if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1]))) + { + ($self,$x,$y,@r) = objectify(2,@_); + } + + return $x if $x->{sign} =~ /^[+-]inf$/; # -inf/+inf ** x + return $x->bnan() if $x->{sign} eq $nan || $y->{sign} eq $nan; + return $x->bone(@r) if $y->is_zero(); + return $x->round(@r) if $x->is_one() || $y->is_one(); + + if ($x->{sign} eq '-' && $MBI->_is_one($x->{_n}) && $MBI->_is_one($x->{_d})) + { + # if $x == -1 and odd/even y => +1/-1 + return $y->is_odd() ? $x->round(@r) : $x->babs()->round(@r); + # my Casio FX-5500L has a bug here: -1 ** 2 is -1, but -1 * -1 is 1; + } + # 1 ** -y => 1 / (1 ** |y|) + # so do test for negative $y after above's clause + + return $x->round(@r) if $x->is_zero(); # 0**y => 0 (if not y <= 0) + + # shortcut if y == 1/N (is then sqrt() respective broot()) + if ($MBI->_is_one($y->{_n})) + { + return $x->bsqrt(@r) if $MBI->_is_two($y->{_d}); # 1/2 => sqrt + return $x->broot($MBI->_str($y->{_d}),@r); # 1/N => root(N) + } + + # shortcut y/1 (and/or x/1) + if ($MBI->_is_one($y->{_d})) + { + # shortcut for x/1 and y/1 + if ($MBI->_is_one($x->{_d})) + { + $x->{_n} = $MBI->_pow($x->{_n},$y->{_n}); # x/1 ** y/1 => (x ** y)/1 + if ($y->{sign} eq '-') + { + # 0.2 ** -3 => 1/(0.2 ** 3) + ($x->{_n},$x->{_d}) = ($x->{_d},$x->{_n}); # swap + } + # correct sign; + ** + => + + if ($x->{sign} eq '-') + { + # - * - => +, - * - * - => - + $x->{sign} = '+' if $MBI->_is_even($y->{_n}); + } + return $x->round(@r); + } + # x/z ** y/1 + $x->{_n} = $MBI->_pow($x->{_n},$y->{_n}); # 5/2 ** y/1 => 5 ** y / 2 ** y + $x->{_d} = $MBI->_pow($x->{_d},$y->{_n}); + if ($y->{sign} eq '-') + { + # 0.2 ** -3 => 1/(0.2 ** 3) + ($x->{_n},$x->{_d}) = ($x->{_d},$x->{_n}); # swap + } + # correct sign; + ** + => + + if ($x->{sign} eq '-') + { + # - * - => +, - * - * - => - + $x->{sign} = '+' if $MBI->_is_even($y->{_n}); + } + return $x->round(@r); + } + +# print STDERR "# $x $y\n"; + + # otherwise: + + # n/d n ______________ + # a/b = -\/ (a/b) ** d + + # (a/b) ** n == (a ** n) / (b ** n) + $MBI->_pow($x->{_n}, $y->{_n} ); + $MBI->_pow($x->{_d}, $y->{_n} ); + + return $x->broot($MBI->_str($y->{_d}),@r); # n/d => root(n) + } + +sub blog + { + # set up parameters + my ($self,$x,$y,@r) = (ref($_[0]),@_); + + # objectify is costly, so avoid it + if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1]))) + { + ($self,$x,$y,@r) = objectify(2,$class,@_); + } + + # blog(1,Y) => 0 + return $x->bzero() if $x->is_one() && $y->{sign} eq '+'; + + # $x <= 0 => NaN + return $x->bnan() if $x->is_zero() || $x->{sign} ne '+' || $y->{sign} ne '+'; + + if ($x->is_int() && $y->is_int()) + { + return $self->new($x->as_number()->blog($y->as_number(),@r)); + } + + # do it with floats + $x->_new_from_float( $x->_as_float()->blog(Math::BigFloat->new("$y"),@r) ); + } + +sub bexp + { + # set up parameters + my ($self,$x,$y,@r) = (ref($_[0]),@_); + + # objectify is costly, so avoid it + if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1]))) + { + ($self,$x,$y,@r) = objectify(2,$class,@_); + } + + return $x->binf(@r) if $x->{sign} eq '+inf'; + return $x->bzero(@r) if $x->{sign} eq '-inf'; + + # we need to limit the accuracy to protect against overflow + my $fallback = 0; + my ($scale,@params); + ($x,@params) = $x->_find_round_parameters(@r); + + # also takes care of the "error in _find_round_parameters?" case + return $x if $x->{sign} eq 'NaN'; + + # no rounding at all, so must use fallback + if (scalar @params == 0) + { + # simulate old behaviour + $params[0] = $self->div_scale(); # and round to it as accuracy + $params[1] = undef; # P = undef + $scale = $params[0]+4; # at least four more for proper round + $params[2] = $r[2]; # round mode by caller or undef + $fallback = 1; # to clear a/p afterwards + } + else + { + # the 4 below is empirical, and there might be cases where it's not enough... + $scale = abs($params[0] || $params[1]) + 4; # take whatever is defined + } + + return $x->bone(@params) if $x->is_zero(); + + # See the comments in Math::BigFloat on how this algorithm works. + # Basically we calculate A and B (where B is faculty(N)) so that A/B = e + + my $x_org = $x->copy(); + if ($scale <= 75) + { + # set $x directly from a cached string form + $x->{_n} = $MBI->_new("90933395208605785401971970164779391644753259799242"); + $x->{_d} = $MBI->_new("33452526613163807108170062053440751665152000000000"); + $x->{sign} = '+'; + } + else + { + # compute A and B so that e = A / B. + + # After some terms we end up with this, so we use it as a starting point: + my $A = $MBI->_new("90933395208605785401971970164779391644753259799242"); + my $F = $MBI->_new(42); my $step = 42; + + # Compute how many steps we need to take to get $A and $B sufficiently big + my $steps = Math::BigFloat::_len_to_steps($scale - 4); +# print STDERR "# Doing $steps steps for ", $scale-4, " digits\n"; + while ($step++ <= $steps) + { + # calculate $a * $f + 1 + $A = $MBI->_mul($A, $F); + $A = $MBI->_inc($A); + # increment f + $F = $MBI->_inc($F); + } + # compute $B as factorial of $steps (this is faster than doing it manually) + my $B = $MBI->_fac($MBI->_new($steps)); + +# print "A ", $MBI->_str($A), "\nB ", $MBI->_str($B), "\n"; + + $x->{_n} = $A; + $x->{_d} = $B; + $x->{sign} = '+'; + } + + # $x contains now an estimate of e, with some surplus digits, so we can round + if (!$x_org->is_one()) + { + # raise $x to the wanted power and round it in one step: + $x->bpow($x_org, @params); + } + else + { + # else just round the already computed result + delete $x->{_a}; delete $x->{_p}; + # shortcut to not run through _find_round_parameters again + if (defined $params[0]) + { + $x->bround($params[0],$params[2]); # then round accordingly + } + else + { + $x->bfround($params[1],$params[2]); # then round accordingly + } + } + if ($fallback) + { + # clear a/p after round, since user did not request it + delete $x->{_a}; delete $x->{_p}; + } + + $x; + } + +sub bnok + { + # set up parameters + my ($self,$x,$y,@r) = (ref($_[0]),@_); + + # objectify is costly, so avoid it + if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1]))) + { + ($self,$x,$y,@r) = objectify(2,$class,@_); + } + + # do it with floats + $x->_new_from_float( $x->_as_float()->bnok(Math::BigFloat->new("$y"),@r) ); + } + +sub _float_from_part + { + my $x = shift; + + my $f = Math::BigFloat->bzero(); + $f->{_m} = $MBI->_copy($x); + $f->{_e} = $MBI->_zero(); + + $f; + } + +sub _as_float + { + my $x = shift; + + local $Math::BigFloat::upgrade = undef; + local $Math::BigFloat::accuracy = undef; + local $Math::BigFloat::precision = undef; + # 22/7 => 3.142857143.. + + my $a = $x->accuracy() || 0; + if ($a != 0 || !$MBI->_is_one($x->{_d})) + { + # n/d + return scalar Math::BigFloat->new($x->{sign} . $MBI->_str($x->{_n}))->bdiv( $MBI->_str($x->{_d}), $x->accuracy()); + } + # just n + Math::BigFloat->new($x->{sign} . $MBI->_str($x->{_n})); + } + +sub broot + { + # set up parameters + my ($self,$x,$y,@r) = (ref($_[0]),@_); + # objectify is costly, so avoid it + if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1]))) + { + ($self,$x,$y,@r) = objectify(2,@_); + } + + if ($x->is_int() && $y->is_int()) + { + return $self->new($x->as_number()->broot($y->as_number(),@r)); + } + + # do it with floats + $x->_new_from_float( $x->_as_float()->broot($y->_as_float(),@r) )->bnorm()->bround(@r); + } + +sub bmodpow + { + # set up parameters + my ($self,$x,$y,$m,@r) = (ref($_[0]),@_); + # objectify is costly, so avoid it + if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1]))) + { + ($self,$x,$y,$m,@r) = objectify(3,@_); + } + + # $x or $y or $m are NaN or +-inf => NaN + return $x->bnan() + if $x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/ || + $m->{sign} !~ /^[+-]$/; + + if ($x->is_int() && $y->is_int() && $m->is_int()) + { + return $self->new($x->as_number()->bmodpow($y->as_number(),$m,@r)); + } + + warn ("bmodpow() not fully implemented"); + $x->bnan(); + } + +sub bmodinv + { + # set up parameters + my ($self,$x,$y,@r) = (ref($_[0]),@_); + # objectify is costly, so avoid it + if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1]))) + { + ($self,$x,$y,@r) = objectify(2,@_); + } + + # $x or $y are NaN or +-inf => NaN + return $x->bnan() + if $x->{sign} !~ /^[+-]$/ || $y->{sign} !~ /^[+-]$/; + + if ($x->is_int() && $y->is_int()) + { + return $self->new($x->as_number()->bmodinv($y->as_number(),@r)); + } + + warn ("bmodinv() not fully implemented"); + $x->bnan(); + } + +sub bsqrt + { + my ($self,$x,@r) = ref($_[0]) ? (ref($_[0]),@_) : objectify(1,@_); + + return $x->bnan() if $x->{sign} !~ /^[+]/; # NaN, -inf or < 0 + return $x if $x->{sign} eq '+inf'; # sqrt(inf) == inf + return $x->round(@r) if $x->is_zero() || $x->is_one(); + + local $Math::BigFloat::upgrade = undef; + local $Math::BigFloat::downgrade = undef; + local $Math::BigFloat::precision = undef; + local $Math::BigFloat::accuracy = undef; + local $Math::BigInt::upgrade = undef; + local $Math::BigInt::precision = undef; + local $Math::BigInt::accuracy = undef; + + $x->{_n} = _float_from_part( $x->{_n} )->bsqrt(); + $x->{_d} = _float_from_part( $x->{_d} )->bsqrt(); + + # XXX TODO: we probably can optimze this: + + # if sqrt(D) was not integer + if ($x->{_d}->{_es} ne '+') + { + $x->{_n}->blsft($x->{_d}->exponent()->babs(),10); # 7.1/4.51 => 7.1/45.1 + $x->{_d} = $MBI->_copy( $x->{_d}->{_m} ); # 7.1/45.1 => 71/45.1 + } + # if sqrt(N) was not integer + if ($x->{_n}->{_es} ne '+') + { + $x->{_d}->blsft($x->{_n}->exponent()->babs(),10); # 71/45.1 => 710/45.1 + $x->{_n} = $MBI->_copy( $x->{_n}->{_m} ); # 710/45.1 => 710/451 + } + + # convert parts to $MBI again + $x->{_n} = $MBI->_lsft( $MBI->_copy( $x->{_n}->{_m} ), $x->{_n}->{_e}, 10) + if ref($x->{_n}) ne $MBI && ref($x->{_n}) ne 'ARRAY'; + $x->{_d} = $MBI->_lsft( $MBI->_copy( $x->{_d}->{_m} ), $x->{_d}->{_e}, 10) + if ref($x->{_d}) ne $MBI && ref($x->{_d}) ne 'ARRAY'; + + $x->bnorm()->round(@r); + } + +sub blsft + { + my ($self,$x,$y,$b,@r) = objectify(3,@_); + + $b = 2 unless defined $b; + $b = $self->new($b) unless ref ($b); + $x->bmul( $b->copy()->bpow($y), @r); + $x; + } + +sub brsft + { + my ($self,$x,$y,$b,@r) = objectify(3,@_); + + $b = 2 unless defined $b; + $b = $self->new($b) unless ref ($b); + $x->bdiv( $b->copy()->bpow($y), @r); + $x; + } + +############################################################################## +# round + +sub round + { + $_[0]; + } + +sub bround + { + $_[0]; + } + +sub bfround + { + $_[0]; + } + +############################################################################## +# comparing + +sub bcmp + { + # compare two signed numbers + + # set up parameters + my ($self,$x,$y) = (ref($_[0]),@_); + # objectify is costly, so avoid it + if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1]))) + { + ($self,$x,$y) = objectify(2,@_); + } + + if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/)) + { + # handle +-inf and NaN + return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan)); + return 0 if $x->{sign} eq $y->{sign} && $x->{sign} =~ /^[+-]inf$/; + return +1 if $x->{sign} eq '+inf'; + return -1 if $x->{sign} eq '-inf'; + return -1 if $y->{sign} eq '+inf'; + return +1; + } + # check sign for speed first + return 1 if $x->{sign} eq '+' && $y->{sign} eq '-'; # does also 0 <=> -y + return -1 if $x->{sign} eq '-' && $y->{sign} eq '+'; # does also -x <=> 0 + + # shortcut + my $xz = $MBI->_is_zero($x->{_n}); + my $yz = $MBI->_is_zero($y->{_n}); + return 0 if $xz && $yz; # 0 <=> 0 + return -1 if $xz && $y->{sign} eq '+'; # 0 <=> +y + return 1 if $yz && $x->{sign} eq '+'; # +x <=> 0 + + my $t = $MBI->_mul( $MBI->_copy($x->{_n}), $y->{_d}); + my $u = $MBI->_mul( $MBI->_copy($y->{_n}), $x->{_d}); + + my $cmp = $MBI->_acmp($t,$u); # signs are equal + $cmp = -$cmp if $x->{sign} eq '-'; # both are '-' => reverse + $cmp; + } + +sub bacmp + { + # compare two numbers (as unsigned) + + # set up parameters + my ($self,$x,$y) = (ref($_[0]),@_); + # objectify is costly, so avoid it + if ((!ref($_[0])) || (ref($_[0]) ne ref($_[1]))) + { + ($self,$x,$y) = objectify(2,$class,@_); + } + + if (($x->{sign} !~ /^[+-]$/) || ($y->{sign} !~ /^[+-]$/)) + { + # handle +-inf and NaN + return undef if (($x->{sign} eq $nan) || ($y->{sign} eq $nan)); + return 0 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} =~ /^[+-]inf$/; + return 1 if $x->{sign} =~ /^[+-]inf$/ && $y->{sign} !~ /^[+-]inf$/; + return -1; + } + + my $t = $MBI->_mul( $MBI->_copy($x->{_n}), $y->{_d}); + my $u = $MBI->_mul( $MBI->_copy($y->{_n}), $x->{_d}); + $MBI->_acmp($t,$u); # ignore signs + } + +############################################################################## +# output conversation + +sub numify + { + # convert 17/8 => float (aka 2.125) + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + return $x->bstr() if $x->{sign} !~ /^[+-]$/; # inf, NaN, etc + + # N/1 => N + my $neg = ''; $neg = '-' if $x->{sign} eq '-'; + return $neg . $MBI->_num($x->{_n}) if $MBI->_is_one($x->{_d}); + + $x->_as_float()->numify() + 0.0; + } + +sub as_number + { + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + # NaN, inf etc + return Math::BigInt->new($x->{sign}) if $x->{sign} !~ /^[+-]$/; + + my $u = Math::BigInt->bzero(); + $u->{sign} = $x->{sign}; + $u->{value} = $MBI->_div( $MBI->_copy($x->{_n}), $x->{_d}); # 22/7 => 3 + $u; + } + +sub as_float + { + # return N/D as Math::BigFloat + + # set up parameters + my ($self,$x,@r) = (ref($_[0]),@_); + # objectify is costly, so avoid it + ($self,$x,@r) = objectify(1,$class,@_) unless ref $_[0]; + + # NaN, inf etc + return Math::BigFloat->new($x->{sign}) if $x->{sign} !~ /^[+-]$/; + + my $u = Math::BigFloat->bzero(); + $u->{sign} = $x->{sign}; + # n + $u->{_m} = $MBI->_copy($x->{_n}); + $u->{_e} = $MBI->_zero(); + $u->bdiv( $MBI->_str($x->{_d}), @r); + # return $u + $u; + } + +sub as_bin + { + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + return $x unless $x->is_int(); + + my $s = $x->{sign}; $s = '' if $s eq '+'; + $s . $MBI->_as_bin($x->{_n}); + } + +sub as_hex + { + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + return $x unless $x->is_int(); + + my $s = $x->{sign}; $s = '' if $s eq '+'; + $s . $MBI->_as_hex($x->{_n}); + } + +sub as_oct + { + my ($self,$x) = ref($_[0]) ? (undef,$_[0]) : objectify(1,@_); + + return $x unless $x->is_int(); + + my $s = $x->{sign}; $s = '' if $s eq '+'; + $s . $MBI->_as_oct($x->{_n}); + } + +############################################################################## + +sub from_hex + { + my $class = shift; + + $class->new(@_); + } + +sub from_bin + { + my $class = shift; + + $class->new(@_); + } + +sub from_oct + { + my $class = shift; + + my @parts; + for my $c (@_) + { + push @parts, Math::BigInt->from_oct($c); + } + $class->new ( @parts ); + } + +############################################################################## +# import + +sub import + { + my $self = shift; + my $l = scalar @_; + my $lib = ''; my @a; + my $try = 'try'; + + for ( my $i = 0; $i < $l ; $i++) + { + if ( $_[$i] eq ':constant' ) + { + # this rest causes overlord er load to step in + overload::constant float => sub { $self->new(shift); }; + } +# elsif ($_[$i] eq 'upgrade') +# { +# # this causes upgrading +# $upgrade = $_[$i+1]; # or undef to disable +# $i++; +# } + elsif ($_[$i] eq 'downgrade') + { + # this causes downgrading + $downgrade = $_[$i+1]; # or undef to disable + $i++; + } + elsif ($_[$i] =~ /^(lib|try|only)\z/) + { + $lib = $_[$i+1] || ''; # default Calc + $try = $1; # lib, try or only + $i++; + } + elsif ($_[$i] eq 'with') + { + # this argument is no longer used + #$MBI = $_[$i+1] || 'Math::BigInt::Calc'; # default Math::BigInt::Calc + $i++; + } + else + { + push @a, $_[$i]; + } + } + require Math::BigInt; + + # let use Math::BigInt lib => 'GMP'; use Math::BigRat; still have GMP + if ($lib ne '') + { + my @c = split /\s*,\s*/, $lib; + foreach (@c) + { + $_ =~ tr/a-zA-Z0-9://cd; # limit to sane characters + } + $lib = join(",", @c); + } + my @import = ('objectify'); + push @import, $try => $lib if $lib ne ''; + + # MBI already loaded, so feed it our lib arguments + Math::BigInt->import( @import ); + + $MBI = Math::BigFloat->config()->{lib}; + + # register us with MBI to get notified of future lib changes + Math::BigInt::_register_callback( $self, sub { $MBI = $_[0]; } ); + + # any non :constant stuff is handled by our parent, Exporter (loaded + # by Math::BigFloat, even if @_ is empty, to give it a chance + $self->SUPER::import(@a); # for subclasses + $self->export_to_level(1,$self,@a); # need this, too + } + +1; + +__END__ + +=head1 NAME + +Math::BigRat - Arbitrary big rational numbers + +=head1 SYNOPSIS + + use Math::BigRat; + + my $x = Math::BigRat->new('3/7'); $x += '5/9'; + + print $x->bstr(),"\n"; + print $x ** 2,"\n"; + + my $y = Math::BigRat->new('inf'); + print "$y ", ($y->is_inf ? 'is' : 'is not') , " infinity\n"; + + my $z = Math::BigRat->new(144); $z->bsqrt(); + +=head1 DESCRIPTION + +Math::BigRat complements Math::BigInt and Math::BigFloat by providing support +for arbitrary big rational numbers. + +=head2 MATH LIBRARY + +You can change the underlying module that does the low-level +math operations by using: + + use Math::BigRat try => 'GMP'; + +Note: This needs Math::BigInt::GMP installed. + +The following would first try to find Math::BigInt::Foo, then +Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc: + + use Math::BigRat try => 'Foo,Math::BigInt::Bar'; + +If you want to get warned when the fallback occurs, replace "try" with +"lib": + + use Math::BigRat lib => 'Foo,Math::BigInt::Bar'; + +If you want the code to die instead, replace "try" with +"only": + + use Math::BigRat only => 'Foo,Math::BigInt::Bar'; + +=head1 METHODS + +Any methods not listed here are derived from Math::BigFloat (or +Math::BigInt), so make sure you check these two modules for further +information. + +=head2 new() + + $x = Math::BigRat->new('1/3'); + +Create a new Math::BigRat object. Input can come in various forms: + + $x = Math::BigRat->new(123); # scalars + $x = Math::BigRat->new('inf'); # infinity + $x = Math::BigRat->new('123.3'); # float + $x = Math::BigRat->new('1/3'); # simple string + $x = Math::BigRat->new('1 / 3'); # spaced + $x = Math::BigRat->new('1 / 0.1'); # w/ floats + $x = Math::BigRat->new(Math::BigInt->new(3)); # BigInt + $x = Math::BigRat->new(Math::BigFloat->new('3.1')); # BigFloat + $x = Math::BigRat->new(Math::BigInt::Lite->new('2')); # BigLite + + # You can also give D and N as different objects: + $x = Math::BigRat->new( + Math::BigInt->new(-123), + Math::BigInt->new(7), + ); # => -123/7 + +=head2 numerator() + + $n = $x->numerator(); + +Returns a copy of the numerator (the part above the line) as signed BigInt. + +=head2 denominator() + + $d = $x->denominator(); + +Returns a copy of the denominator (the part under the line) as positive BigInt. + +=head2 parts() + + ($n,$d) = $x->parts(); + +Return a list consisting of (signed) numerator and (unsigned) denominator as +BigInts. + +=head2 numify() + + my $y = $x->numify(); + +Returns the object as a scalar. This will lose some data if the object +cannot be represented by a normal Perl scalar (integer or float), so +use L<as_int()> or L<as_float()> instead. + +This routine is automatically used whenever a scalar is required: + + my $x = Math::BigRat->new('3/1'); + @array = (0,1,2,3); + $y = $array[$x]; # set $y to 3 + +=head2 as_int()/as_number() + + $x = Math::BigRat->new('13/7'); + print $x->as_int(),"\n"; # '1' + +Returns a copy of the object as BigInt, truncated to an integer. + +C<as_number()> is an alias for C<as_int()>. + +=head2 as_float() + + $x = Math::BigRat->new('13/7'); + print $x->as_float(),"\n"; # '1' + + $x = Math::BigRat->new('2/3'); + print $x->as_float(5),"\n"; # '0.66667' + +Returns a copy of the object as BigFloat, preserving the +accuracy as wanted, or the default of 40 digits. + +This method was added in v0.22 of Math::BigRat (April 2008). + +=head2 as_hex() + + $x = Math::BigRat->new('13'); + print $x->as_hex(),"\n"; # '0xd' + +Returns the BigRat as hexadecimal string. Works only for integers. + +=head2 as_bin() + + $x = Math::BigRat->new('13'); + print $x->as_bin(),"\n"; # '0x1101' + +Returns the BigRat as binary string. Works only for integers. + +=head2 as_oct() + + $x = Math::BigRat->new('13'); + print $x->as_oct(),"\n"; # '015' + +Returns the BigRat as octal string. Works only for integers. + +=head2 from_hex()/from_bin()/from_oct() + + my $h = Math::BigRat->from_hex('0x10'); + my $b = Math::BigRat->from_bin('0b10000000'); + my $o = Math::BigRat->from_oct('020'); + +Create a BigRat from an hexadecimal, binary or octal number +in string form. + +=head2 length() + + $len = $x->length(); + +Return the length of $x in digitis for integer values. + +=head2 digit() + + print Math::BigRat->new('123/1')->digit(1); # 1 + print Math::BigRat->new('123/1')->digit(-1); # 3 + +Return the N'ths digit from X when X is an integer value. + +=head2 bnorm() + + $x->bnorm(); + +Reduce the number to the shortest form. This routine is called +automatically whenever it is needed. + +=head2 bfac() + + $x->bfac(); + +Calculates the factorial of $x. For instance: + + print Math::BigRat->new('3/1')->bfac(),"\n"; # 1*2*3 + print Math::BigRat->new('5/1')->bfac(),"\n"; # 1*2*3*4*5 + +Works currently only for integers. + +=head2 bround()/round()/bfround() + +Are not yet implemented. + +=head2 bmod() + + use Math::BigRat; + my $x = Math::BigRat->new('7/4'); + my $y = Math::BigRat->new('4/3'); + print $x->bmod($y); + +Set $x to the remainder of the division of $x by $y. + +=head2 bneg() + + $x->bneg(); + +Used to negate the object in-place. + +=head2 is_one() + + print "$x is 1\n" if $x->is_one(); + +Return true if $x is exactly one, otherwise false. + +=head2 is_zero() + + print "$x is 0\n" if $x->is_zero(); + +Return true if $x is exactly zero, otherwise false. + +=head2 is_pos()/is_positive() + + print "$x is >= 0\n" if $x->is_positive(); + +Return true if $x is positive (greater than or equal to zero), otherwise +false. Please note that '+inf' is also positive, while 'NaN' and '-inf' aren't. + +C<is_positive()> is an alias for C<is_pos()>. + +=head2 is_neg()/is_negative() + + print "$x is < 0\n" if $x->is_negative(); + +Return true if $x is negative (smaller than zero), otherwise false. Please +note that '-inf' is also negative, while 'NaN' and '+inf' aren't. + +C<is_negative()> is an alias for C<is_neg()>. + +=head2 is_int() + + print "$x is an integer\n" if $x->is_int(); + +Return true if $x has a denominator of 1 (e.g. no fraction parts), otherwise +false. Please note that '-inf', 'inf' and 'NaN' aren't integer. + +=head2 is_odd() + + print "$x is odd\n" if $x->is_odd(); + +Return true if $x is odd, otherwise false. + +=head2 is_even() + + print "$x is even\n" if $x->is_even(); + +Return true if $x is even, otherwise false. + +=head2 bceil() + + $x->bceil(); + +Set $x to the next bigger integer value (e.g. truncate the number to integer +and then increment it by one). + +=head2 bfloor() + + $x->bfloor(); + +Truncate $x to an integer value. + +=head2 bsqrt() + + $x->bsqrt(); + +Calculate the square root of $x. + +=head2 broot() + + $x->broot($n); + +Calculate the N'th root of $x. + +=head2 badd()/bmul()/bsub()/bdiv()/bdec()/binc() + +Please see the documentation in L<Math::BigInt>. + +=head2 copy() + + my $z = $x->copy(); + +Makes a deep copy of the object. + +Please see the documentation in L<Math::BigInt> for further details. + +=head2 bstr()/bsstr() + + my $x = Math::BigInt->new('8/4'); + print $x->bstr(),"\n"; # prints 1/2 + print $x->bsstr(),"\n"; # prints 1/2 + +Return a string representating this object. + +=head2 bacmp()/bcmp() + +Used to compare numbers. + +Please see the documentation in L<Math::BigInt> for further details. + +=head2 blsft()/brsft() + +Used to shift numbers left/right. + +Please see the documentation in L<Math::BigInt> for further details. + +=head2 bpow() + + $x->bpow($y); + +Compute $x ** $y. + +Please see the documentation in L<Math::BigInt> for further details. + +=head2 bexp() + + $x->bexp($accuracy); # calculate e ** X + +Calculates two integers A and B so that A/B is equal to C<e ** $x>, where C<e> is +Euler's number. + +This method was added in v0.20 of Math::BigRat (May 2007). + +See also L<blog()>. + +=head2 bnok() + + $x->bnok($y); # x over y (binomial coefficient n over k) + +Calculates the binomial coefficient n over k, also called the "choose" +function. The result is equivalent to: + + ( n ) n! + | - | = ------- + ( k ) k!(n-k)! + +This method was added in v0.20 of Math::BigRat (May 2007). + +=head2 config() + + use Data::Dumper; + + print Dumper ( Math::BigRat->config() ); + print Math::BigRat->config()->{lib},"\n"; + +Returns a hash containing the configuration, e.g. the version number, lib +loaded etc. The following hash keys are currently filled in with the +appropriate information. + + key RO/RW Description + Example + ============================================================ + lib RO Name of the Math library + Math::BigInt::Calc + lib_version RO Version of 'lib' + 0.30 + class RO The class of config you just called + Math::BigRat + version RO version number of the class you used + 0.10 + upgrade RW To which class numbers are upgraded + undef + downgrade RW To which class numbers are downgraded + undef + precision RW Global precision + undef + accuracy RW Global accuracy + undef + round_mode RW Global round mode + even + div_scale RW Fallback accuracy for div + 40 + trap_nan RW Trap creation of NaN (undef = no) + undef + trap_inf RW Trap creation of +inf/-inf (undef = no) + undef + +By passing a reference to a hash you may set the configuration values. This +works only for values that a marked with a C<RW> above, anything else is +read-only. + +=head2 objectify() + +This is an internal routine that turns scalars into objects. + +=head1 BUGS + +Some things are not yet implemented, or only implemented half-way: + +=over 2 + +=item inf handling (partial) + +=item NaN handling (partial) + +=item rounding (not implemented except for bceil/bfloor) + +=item $x ** $y where $y is not an integer + +=item bmod(), blog(), bmodinv() and bmodpow() (partial) + +=back + +=head1 LICENSE + +This program is free software; you may redistribute it and/or modify it under +the same terms as Perl itself. + +=head1 SEE ALSO + +L<Math::BigFloat> and L<Math::Big> as well as L<Math::BigInt::BitVect>, +L<Math::BigInt::Pari> and L<Math::BigInt::GMP>. + +See L<http://search.cpan.org/search?dist=bignum> for a way to use +Math::BigRat. + +The package at L<http://search.cpan.org/search?dist=Math%3A%3ABigRat> +may contain more documentation and examples as well as testcases. + +=head1 AUTHORS + +(C) by Tels L<http://bloodgate.com/> 2001 - 2009. + +Currently maintained by Jonathan "Duke" Leto <jonathan@leto.net> L<http://leto.net> + +=cut |