[p5sagit/p5-mst-13.2.git] / lib / bigrat.pm

package bigrat;
use 5.006002;

$VERSION = '0.10';
require Exporter;
@ISA		= qw( Exporter );
@EXPORT_OK	= qw( ); 
@EXPORT		= qw( inf NaN ); 

use strict;
use overload;

############################################################################## 

# These are all alike, and thus faked by AUTOLOAD

my @faked = qw/round_mode accuracy precision div_scale/;
use vars qw/$VERSION $AUTOLOAD $_lite/;		# _lite for testsuite

sub AUTOLOAD
  {
  my $name = $AUTOLOAD;

  $name =~ s/.*:://;    # split package
  no strict 'refs';
  foreach my $n (@faked)
    {
    if ($n eq $name)
      {
      *{"bigrat::$name"} = sub 
        {
        my $self = shift;
        no strict 'refs';
        if (defined $_[0])
          {
          Math::BigInt->$name($_[0]);
          Math::BigFloat->$name($_[0]);
          return Math::BigRat->$name($_[0]);
          }
        return Math::BigInt->$name();
        };
      return &$name;
      }
    }
 
  # delayed load of Carp and avoid recursion
  require Carp;
  Carp::croak ("Can't call bigrat\-\>$name, not a valid method");
  }

sub upgrade
  {
  my $self = shift;
  no strict 'refs';
#  if (defined $_[0])
#    {
#    $Math::BigInt::upgrade = $_[0];
#    $Math::BigFloat::upgrade = $_[0];
#    }
  $Math::BigInt::upgrade;
  }

sub _binary_constant
  {
  # this takes a binary/hexadecimal/octal constant string and returns it
  # as string suitable for new. Basically it converts octal to decimal, and
  # passes every thing else unmodified back.
  my $string = shift;

  return Math::BigInt->new($string) if $string =~ /^0[bx]/;

  # so it must be an octal constant
  Math::BigInt->from_oct($string);
  }

sub import 
  {
  my $self = shift;

  # see also bignum->import() for additional comments

  # some defaults
  my $lib = ''; my $lib_kind = 'try'; my $upgrade = 'Math::BigFloat';

  my @import = ( ':constant' );				# drive it w/ constant
  my @a = @_; my $l = scalar @_; my $j = 0;
  my ($a,$p);
  my ($ver,$trace);					# version? trace?
  for ( my $i = 0; $i < $l ; $i++,$j++ )
    {
    if ($_[$i] eq 'upgrade')
      {
      # this causes upgrading
      $upgrade = $_[$i+1];		# or undef to disable
      my $s = 2; $s = 1 if @a-$j < 2;	# avoid "can not modify non-existant..."
      splice @a, $j, $s; $j -= $s;
      }
    elsif ($_[$i] =~ /^(l|lib|try|only)$/)
      {
      # this causes a different low lib to take care...
      $lib_kind = $1; $lib_kind = 'lib' if $lib_kind eq 'l';
      $lib = $_[$i+1] || '';
      my $s = 2; $s = 1 if @a-$j < 2;	# avoid "can not modify non-existant..."
      splice @a, $j, $s; $j -= $s; $i++;
      }
    elsif ($_[$i] =~ /^(a|accuracy)$/)
      {
      $a = $_[$i+1];
      my $s = 2; $s = 1 if @a-$j < 2;   # avoid "can not modify non-existant..."
      splice @a, $j, $s; $j -= $s; $i++;
      }
    elsif ($_[$i] =~ /^(p|precision)$/)
      {
      $p = $_[$i+1];
      my $s = 2; $s = 1 if @a-$j < 2;   # avoid "can not modify non-existant..."
      splice @a, $j, $s; $j -= $s; $i++;
      }
    elsif ($_[$i] =~ /^(v|version)$/)
      {
      $ver = 1;
      splice @a, $j, 1; $j --;
      }
    elsif ($_[$i] =~ /^(t|trace)$/)
      {
      $trace = 1;
      splice @a, $j, 1; $j --;
      }
    else
      {
      die ("unknown option $_[$i]");
      }
    }
  my $class;
  $_lite = 0;                                   # using M::BI::L ?
  if ($trace)
    {
    require Math::BigInt::Trace; $class = 'Math::BigInt::Trace';
    $upgrade = 'Math::BigFloat::Trace';
    }
  else
    {
    # see if we can find Math::BigInt::Lite
    if (!defined $a && !defined $p)             # rounding won't work to well
      {
      eval 'require Math::BigInt::Lite;';
      if ($@ eq '')
        {
        @import = ( );                          # :constant in Lite, not MBI
        Math::BigInt::Lite->import( ':constant' );
        $_lite= 1;                              # signal okay
        }
      }
    require Math::BigInt if $_lite == 0;        # not already loaded?
    $class = 'Math::BigInt';                    # regardless of MBIL or not
    }
  push @import, $lib_kind => $lib if $lib ne ''; 
  # Math::BigInt::Trace or plain Math::BigInt
  $class->import(@import, upgrade => $upgrade);

  require Math::BigFloat;
  Math::BigFloat->import( upgrade => 'Math::BigRat', ':constant' );
  require Math::BigRat;

  bigrat->accuracy($a) if defined $a;
  bigrat->precision($p) if defined $p;
  if ($ver)
    {
    print "bigrat\t\t\t v$VERSION\n";
    print "Math::BigInt::Lite\t v$Math::BigInt::Lite::VERSION\n" if $_lite;  
    print "Math::BigInt\t\t v$Math::BigInt::VERSION";
    my $config = Math::BigInt->config();
    print " lib => $config->{lib} v$config->{lib_version}\n";
    print "Math::BigFloat\t\t v$Math::BigFloat::VERSION\n";
    print "Math::BigRat\t\t v$Math::BigRat::VERSION\n";
    exit;
    }

  # Take care of octal/hexadecimal constants
  overload::constant binary => sub { _binary_constant(shift) };

  $self->export_to_level(1,$self,@a);           # export inf and NaN
  }

sub inf () { Math::BigInt->binf(); }
sub NaN () { Math::BigInt->bnan(); }

1;

__END__

=head1 NAME

bigrat - Transparent BigNumber/BigRational support for Perl

=head1 SYNOPSIS

  use bigrat;

  $x = 2 + 4.5,"\n";			# BigFloat 6.5
  print 1/3 + 1/4,"\n";			# produces 7/12

=head1 DESCRIPTION

All operators (including basic math operations) are overloaded. Integer and
floating-point constants are created as proper BigInts or BigFloats,
respectively.

Other than L<bignum>, this module upgrades to Math::BigRat, meaning that
instead of 2.5 you will get 2+1/2 as output.

=head2 Modules Used

C<bigrat> is just a thin wrapper around various modules of the Math::BigInt
family. Think of it as the head of the family, who runs the shop, and orders
the others to do the work.

The following modules are currently used by bignum:

        Math::BigInt::Lite      (for speed, and only if it is loadable)
        Math::BigInt
        Math::BigFloat
        Math::BigRat

=head2 Math Library

Math with the numbers is done (by default) by a module called
Math::BigInt::Calc. This is equivalent to saying:

	use bigrat lib => 'Calc';

You can change this by using:

        use bignum lib => 'GMP';

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 bigrat lib => 'Foo,Math::BigInt::Bar';

Using C<lib> warns if none of the specified libraries can be found and
L<Math::BigInt> did fall back to one of the default libraries.
To supress this warning, use C<try> instead:

        use bignum try => 'GMP';

If you want the code to die instead of falling back, use C<only> instead:

        use bignum only => 'GMP';

Please see respective module documentation for further details.

=head2 Sign

The sign is either '+', '-', 'NaN', '+inf' or '-inf'.

A sign of 'NaN' is used to represent the result when input arguments are not
numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively
minus infinity. You will get '+inf' when dividing a positive number by 0, and
'-inf' when dividing any negative number by 0.

=head2 Methods

Since all numbers are not objects, you can use all functions that are part of
the BigInt or BigFloat API. It is wise to use only the bxxx() notation, and not
the fxxx() notation, though. This makes you independed on the fact that the
underlying object might morph into a different class than BigFloat.

=over 2

=item inf()

A shortcut to return Math::BigInt->binf(). Useful because Perl does not always
handle bareword C<inf> properly.

=item NaN()

A shortcut to return Math::BigInt->bnan(). Useful because Perl does not always
handle bareword C<NaN> properly.

=item upgrade()

Return the class that numbers are upgraded to, is in fact returning
C<$Math::BigInt::upgrade>.

=back

=head2 MATH LIBRARY

Math with the numbers is done (by default) by a module called

=head2 Cavaet

But a warning is in order. When using the following to make a copy of a number,
only a shallow copy will be made.

        $x = 9; $y = $x;
        $x = $y = 7;

If you want to make a real copy, use the following:

	$y = $x->copy();

Using the copy or the original with overloaded math is okay, e.g. the
following work:

        $x = 9; $y = $x;
        print $x + 1, " ", $y,"\n";     # prints 10 9

but calling any method that modifies the number directly will result in
B<both> the original and the copy being destroyed:

        $x = 9; $y = $x;
        print $x->badd(1), " ", $y,"\n";        # prints 10 10

        $x = 9; $y = $x;
        print $x->binc(1), " ", $y,"\n";        # prints 10 10

        $x = 9; $y = $x;
        print $x->bmul(2), " ", $y,"\n";        # prints 18 18

Using methods that do not modify, but testthe contents works:

        $x = 9; $y = $x;
        $z = 9 if $x->is_zero();                # works fine

See the documentation about the copy constructor and C<=> in overload, as
well as the documentation in BigInt for further details.

=head2 Options

bignum recognizes some options that can be passed while loading it via use.
The options can (currently) be either a single letter form, or the long form.
The following options exist:

=over 2

=item a or accuracy

This sets the accuracy for all math operations. The argument must be greater
than or equal to zero. See Math::BigInt's bround() function for details.

	perl -Mbigrat=a,50 -le 'print sqrt(20)'

Note that setting precision and accurary at the same time is not possible.

=item p or precision

This sets the precision for all math operations. The argument can be any
integer. Negative values mean a fixed number of digits after the dot, while
a positive value rounds to this digit left from the dot. 0 or 1 mean round to
integer. See Math::BigInt's bfround() function for details.

	perl -Mbigrat=p,-50 -le 'print sqrt(20)'

Note that setting precision and accurary at the same time is not possible.

=item t or trace

This enables a trace mode and is primarily for debugging bignum or
Math::BigInt/Math::BigFloat.

=item l or lib

Load a different math lib, see L<MATH LIBRARY>.

	perl -Mbigrat=l,GMP -e 'print 2 ** 512'

Currently there is no way to specify more than one library on the command
line. This means the following does not work:

	perl -Mbignum=l,GMP,Pari -e 'print 2 ** 512'

This will be hopefully fixed soon ;)

=item v or version

This prints out the name and version of all modules used and then exits.

	perl -Mbigrat=v

=back

=head1 EXAMPLES
 
	perl -Mbigrat -le 'print sqrt(33)'
	perl -Mbigrat -le 'print 2*255'
	perl -Mbigrat -le 'print 4.5+2*255'
	perl -Mbigrat -le 'print 3/7 + 5/7 + 8/3'	
	perl -Mbigrat -le 'print 12->is_odd()';
	perl -Mbignum=l,GMP -le 'print 7 ** 7777'

=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

Especially L<bignum>.

L<Math::BigFloat>, L<Math::BigInt>, L<Math::BigRat> and L<Math::Big> as well
as L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and  L<Math::BigInt::GMP>.

=head1 AUTHORS

(C) by Tels L<http://bloodgate.com/> in early 2002 - 2007.

=cut
Commit	Line	Data
126f3c5f	1	package bigrat;
95a2d02c	2	use 5.006002;
126f3c5f	3
bd49aa09	4	$VERSION = '0.10';
b68b7ab1	5	require Exporter;
b4bc5691	6	@ISA = qw( Exporter );
	7	@EXPORT_OK = qw( );
	8	@EXPORT = qw( inf NaN );
126f3c5f	9
126f3c5f	10	use strict;
95a2d02c	11	use overload;
126f3c5f	12
	13	##############################################################################
	14
	15	# These are all alike, and thus faked by AUTOLOAD
	16
	17	my @faked = qw/round_mode accuracy precision div_scale/;
	18	use vars qw/$VERSION $AUTOLOAD $_lite/; # _lite for testsuite
	19
	20	sub AUTOLOAD
	21	{
	22	my $name = $AUTOLOAD;
	23
	24	$name =~ s/.*:://; # split package
	25	no strict 'refs';
	26	foreach my $n (@faked)
	27	{
	28	if ($n eq $name)
	29	{
	30	*{"bigrat::$name"} = sub
	31	{
	32	my $self = shift;
	33	no strict 'refs';
	34	if (defined $_[0])
	35	{
	36	Math::BigInt->$name($_[0]);
	37	Math::BigFloat->$name($_[0]);
990fb837	38	return Math::BigRat->$name($_[0]);
126f3c5f	39	}
	40	return Math::BigInt->$name();
	41	};
	42	return &$name;
	43	}
	44	}
	45
	46	# delayed load of Carp and avoid recursion
	47	require Carp;
	48	Carp::croak ("Can't call bigrat\-\>$name, not a valid method");
	49	}
	50
	51	sub upgrade
	52	{
	53	my $self = shift;
	54	no strict 'refs';
	55	# if (defined $_[0])
	56	# {
	57	# $Math::BigInt::upgrade = $_[0];
	58	# $Math::BigFloat::upgrade = $_[0];
	59	# }
95a2d02c	60	$Math::BigInt::upgrade;
	61	}
	62
	63	sub _binary_constant
	64	{
	65	# this takes a binary/hexadecimal/octal constant string and returns it
	66	# as string suitable for new. Basically it converts octal to decimal, and
	67	# passes every thing else unmodified back.
	68	my $string = shift;
	69
	70	return Math::BigInt->new($string) if $string =~ /^0[bx]/;
	71
	72	# so it must be an octal constant
	73	Math::BigInt->from_oct($string);
126f3c5f	74	}
	75
	76	sub import
	77	{
	78	my $self = shift;
	79
	80	# see also bignum->import() for additional comments
	81
	82	# some defaults
bd49aa09	83	my $lib = ''; my $lib_kind = 'try'; my $upgrade = 'Math::BigFloat';
126f3c5f	84
	85	my @import = ( ':constant' ); # drive it w/ constant
	86	my @a = @_; my $l = scalar @_; my $j = 0;
	87	my ($a,$p);
	88	my ($ver,$trace); # version? trace?
	89	for ( my $i = 0; $i < $l ; $i++,$j++ )
	90	{
	91	if ($_[$i] eq 'upgrade')
	92	{
	93	# this causes upgrading
	94	$upgrade = $_[$i+1]; # or undef to disable
	95	my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..."
	96	splice @a, $j, $s; $j -= $s;
	97	}
bd49aa09	98	elsif ($_[$i] =~ /^(l\|lib\|try\|only)$/)
126f3c5f	99	{
126f3c5f	100	# this causes a different low lib to take care...
bd49aa09	101	$lib_kind = $1; $lib_kind = 'lib' if $lib_kind eq 'l';
126f3c5f	102	$lib = $_[$i+1] \|\| '';
126f3c5f	103	my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..."
b68b7ab1	104	splice @a, $j, $s; $j -= $s; $i++;
	105	}
	106	elsif ($_[$i] =~ /^(a\|accuracy)$/)
	107	{
	108	$a = $_[$i+1];
	109	my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..."
	110	splice @a, $j, $s; $j -= $s; $i++;
	111	}
	112	elsif ($_[$i] =~ /^(p\|precision)$/)
	113	{
	114	$p = $_[$i+1];
	115	my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..."
	116	splice @a, $j, $s; $j -= $s; $i++;
126f3c5f	117	}
	118	elsif ($_[$i] =~ /^(v\|version)$/)
	119	{
	120	$ver = 1;
	121	splice @a, $j, 1; $j --;
	122	}
	123	elsif ($_[$i] =~ /^(t\|trace)$/)
	124	{
	125	$trace = 1;
	126	splice @a, $j, 1; $j --;
	127	}
	128	else
	129	{
	130	die ("unknown option $_[$i]");
	131	}
	132	}
	133	my $class;
	134	$_lite = 0; # using M::BI::L ?
	135	if ($trace)
	136	{
	137	require Math::BigInt::Trace; $class = 'Math::BigInt::Trace';
	138	$upgrade = 'Math::BigFloat::Trace';
126f3c5f	139	}
	140	else
	141	{
	142	# see if we can find Math::BigInt::Lite
	143	if (!defined $a && !defined $p) # rounding won't work to well
	144	{
	145	eval 'require Math::BigInt::Lite;';
	146	if ($@ eq '')
	147	{
	148	@import = ( ); # :constant in Lite, not MBI
	149	Math::BigInt::Lite->import( ':constant' );
	150	$_lite= 1; # signal okay
	151	}
	152	}
	153	require Math::BigInt if $_lite == 0; # not already loaded?
	154	$class = 'Math::BigInt'; # regardless of MBIL or not
	155	}
bd49aa09	156	push @import, $lib_kind => $lib if $lib ne '';
126f3c5f	157	# Math::BigInt::Trace or plain Math::BigInt
233f7bc0	158	$class->import(@import, upgrade => $upgrade);
126f3c5f	159
	160	require Math::BigFloat;
	161	Math::BigFloat->import( upgrade => 'Math::BigRat', ':constant' );
	162	require Math::BigRat;
b68b7ab1	163
	164	bigrat->accuracy($a) if defined $a;
	165	bigrat->precision($p) if defined $p;
126f3c5f	166	if ($ver)
	167	{
	168	print "bigrat\t\t\t v$VERSION\n";
	169	print "Math::BigInt::Lite\t v$Math::BigInt::Lite::VERSION\n" if $_lite;
	170	print "Math::BigInt\t\t v$Math::BigInt::VERSION";
	171	my $config = Math::BigInt->config();
	172	print " lib => $config->{lib} v$config->{lib_version}\n";
	173	print "Math::BigFloat\t\t v$Math::BigFloat::VERSION\n";
	174	print "Math::BigRat\t\t v$Math::BigRat::VERSION\n";
	175	exit;
	176	}
95a2d02c	177
	178	# Take care of octal/hexadecimal constants
	179	overload::constant binary => sub { _binary_constant(shift) };
	180
b4bc5691	181	$self->export_to_level(1,$self,@a); # export inf and NaN
126f3c5f	182	}
126f3c5f	183
b4bc5691	184	sub inf () { Math::BigInt->binf(); }
	185	sub NaN () { Math::BigInt->bnan(); }
	186
126f3c5f	187	1;
	188
	189	__END__
	190
	191	=head1 NAME
	192
b1f79218	193	bigrat - Transparent BigNumber/BigRational support for Perl
126f3c5f	194
	195	=head1 SYNOPSIS
	196
	197	use bigrat;
	198
	199	$x = 2 + 4.5,"\n"; # BigFloat 6.5
	200	print 1/3 + 1/4,"\n"; # produces 7/12
	201
	202	=head1 DESCRIPTION
	203
3c4b39be	204	All operators (including basic math operations) are overloaded. Integer and
126f3c5f	205	floating-point constants are created as proper BigInts or BigFloats,
	206	respectively.
	207
	208	Other than L<bignum>, this module upgrades to Math::BigRat, meaning that
	209	instead of 2.5 you will get 2+1/2 as output.
	210
b68b7ab1	211	=head2 Modules Used
126f3c5f	212
	213	C<bigrat> is just a thin wrapper around various modules of the Math::BigInt
	214	family. Think of it as the head of the family, who runs the shop, and orders
	215	the others to do the work.
	216
	217	The following modules are currently used by bignum:
	218
	219	Math::BigInt::Lite (for speed, and only if it is loadable)
	220	Math::BigInt
	221	Math::BigFloat
	222	Math::BigRat
	223
b68b7ab1	224	=head2 Math Library
126f3c5f	225
	226	Math with the numbers is done (by default) by a module called
	227	Math::BigInt::Calc. This is equivalent to saying:
	228
	229	use bigrat lib => 'Calc';
	230
	231	You can change this by using:
	232
bd49aa09	233	use bignum lib => 'GMP';
126f3c5f	234
	235	The following would first try to find Math::BigInt::Foo, then
	236	Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
	237
	238	use bigrat lib => 'Foo,Math::BigInt::Bar';
	239
bd49aa09	240	Using C<lib> warns if none of the specified libraries can be found and
	241	L<Math::BigInt> did fall back to one of the default libraries.
	242	To supress this warning, use C<try> instead:
	243
	244	use bignum try => 'GMP';
	245
	246	If you want the code to die instead of falling back, use C<only> instead:
	247
	248	use bignum only => 'GMP';
	249
126f3c5f	250	Please see respective module documentation for further details.
126f3c5f	251
b68b7ab1	252	=head2 Sign
126f3c5f	253
b68b7ab1	254	The sign is either '+', '-', 'NaN', '+inf' or '-inf'.
126f3c5f	255
	256	A sign of 'NaN' is used to represent the result when input arguments are not
	257	numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively
	258	minus infinity. You will get '+inf' when dividing a positive number by 0, and
	259	'-inf' when dividing any negative number by 0.
	260
b68b7ab1	261	=head2 Methods
126f3c5f	262
	263	Since all numbers are not objects, you can use all functions that are part of
	264	the BigInt or BigFloat API. It is wise to use only the bxxx() notation, and not
	265	the fxxx() notation, though. This makes you independed on the fact that the
	266	underlying object might morph into a different class than BigFloat.
	267
95a2d02c	268	=over 2
	269
	270	=item inf()
	271
	272	A shortcut to return Math::BigInt->binf(). Useful because Perl does not always
	273	handle bareword C<inf> properly.
	274
	275	=item NaN()
	276
	277	A shortcut to return Math::BigInt->bnan(). Useful because Perl does not always
	278	handle bareword C<NaN> properly.
	279
	280	=item upgrade()
	281
	282	Return the class that numbers are upgraded to, is in fact returning
	283	C<$Math::BigInt::upgrade>.
	284
	285	=back
	286
	287	=head2 MATH LIBRARY
	288
	289	Math with the numbers is done (by default) by a module called
	290
	291	=head2 Cavaet
990fb837	292
	293	But a warning is in order. When using the following to make a copy of a number,
	294	only a shallow copy will be made.
	295
	296	$x = 9; $y = $x;
	297	$x = $y = 7;
	298
b68b7ab1	299	If you want to make a real copy, use the following:
	300
	301	$y = $x->copy();
	302
990fb837	303	Using the copy or the original with overloaded math is okay, e.g. the
	304	following work:
	305
	306	$x = 9; $y = $x;
	307	print $x + 1, " ", $y,"\n"; # prints 10 9
	308
	309	but calling any method that modifies the number directly will result in
3c4b39be	310	B<both> the original and the copy being destroyed:
990fb837	311
	312	$x = 9; $y = $x;
	313	print $x->badd(1), " ", $y,"\n"; # prints 10 10
	314
	315	$x = 9; $y = $x;
	316	print $x->binc(1), " ", $y,"\n"; # prints 10 10
	317
	318	$x = 9; $y = $x;
	319	print $x->bmul(2), " ", $y,"\n"; # prints 18 18
	320
	321	Using methods that do not modify, but testthe contents works:
	322
	323	$x = 9; $y = $x;
	324	$z = 9 if $x->is_zero(); # works fine
	325
	326	See the documentation about the copy constructor and C<=> in overload, as
	327	well as the documentation in BigInt for further details.
	328
b68b7ab1	329	=head2 Options
	330
	331	bignum recognizes some options that can be passed while loading it via use.
	332	The options can (currently) be either a single letter form, or the long form.
	333	The following options exist:
	334
	335	=over 2
	336
	337	=item a or accuracy
	338
	339	This sets the accuracy for all math operations. The argument must be greater
	340	than or equal to zero. See Math::BigInt's bround() function for details.
	341
	342	perl -Mbigrat=a,50 -le 'print sqrt(20)'
	343
95a2d02c	344	Note that setting precision and accurary at the same time is not possible.
95a2d02c	345
b68b7ab1	346	=item p or precision
	347
	348	This sets the precision for all math operations. The argument can be any
	349	integer. Negative values mean a fixed number of digits after the dot, while
	350	a positive value rounds to this digit left from the dot. 0 or 1 mean round to
	351	integer. See Math::BigInt's bfround() function for details.
	352
	353	perl -Mbigrat=p,-50 -le 'print sqrt(20)'
	354
95a2d02c	355	Note that setting precision and accurary at the same time is not possible.
95a2d02c	356
b68b7ab1	357	=item t or trace
	358
	359	This enables a trace mode and is primarily for debugging bignum or
	360	Math::BigInt/Math::BigFloat.
	361
	362	=item l or lib
	363
	364	Load a different math lib, see L<MATH LIBRARY>.
	365
	366	perl -Mbigrat=l,GMP -e 'print 2 ** 512'
	367
	368	Currently there is no way to specify more than one library on the command
95a2d02c	369	line. This means the following does not work:
	370
	371	perl -Mbignum=l,GMP,Pari -e 'print 2 ** 512'
	372
	373	This will be hopefully fixed soon ;)
b68b7ab1	374
	375	=item v or version
	376
	377	This prints out the name and version of all modules used and then exits.
	378
	379	perl -Mbigrat=v
	380
95a2d02c	381	=back
95a2d02c	382
126f3c5f	383	=head1 EXAMPLES
	384
	385	perl -Mbigrat -le 'print sqrt(33)'
	386	perl -Mbigrat -le 'print 2*255'
	387	perl -Mbigrat -le 'print 4.5+2*255'
	388	perl -Mbigrat -le 'print 3/7 + 5/7 + 8/3'
	389	perl -Mbigrat -le 'print 12->is_odd()';
95a2d02c	390	perl -Mbignum=l,GMP -le 'print 7 ** 7777'
126f3c5f	391
	392	=head1 LICENSE
	393
	394	This program is free software; you may redistribute it and/or modify it under
	395	the same terms as Perl itself.
	396
	397	=head1 SEE ALSO
	398
	399	Especially L<bignum>.
	400
	401	L<Math::BigFloat>, L<Math::BigInt>, L<Math::BigRat> and L<Math::Big> as well
	402	as L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>.
	403
	404	=head1 AUTHORS
	405
95a2d02c	406	(C) by Tels L<http://bloodgate.com/> in early 2002 - 2007.
126f3c5f	407
126f3c5f	408	=cut