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Math::BigRat
Math::BigRat - Arbitrary big rational numbers
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();
Math::BigRat complements Math::BigInt and Math::BigFloat by providing support
for arbitrary big rational numbers.
Math with the numbers is done (by default) by a module called
Math::BigInt::Calc. This is equivalent to saying:
use Math::BigRat lib => 'Calc';
You can change this by using:
use Math::BigRat lib => 'BitVect';
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 lib => 'Foo,Math::BigInt::Bar';
Calc.pm uses as internal format an array of elements of some decimal base (usually 1e7, but this might be different for some systems) with the least
significant digit first, while BitVect.pm uses a bit vector of base 2, most
significant bit first. Other modules might use even different means of
representing the numbers. See the respective module documentation for further
details.
Currently the following replacement libraries exist, search for them at CPAN:
Math::BigInt::BitVect
Math::BigInt::GMP
Math::BigInt::Pari
Math::BigInt::FastCalc
Any methods not listed here are dervied from Math::BigFloat (or
Math::BigInt), so make sure you check these two modules for further
information.
$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
$n = $x->numerator();
Returns a copy of the numerator (the part above the line) as signed BigInt.
$d = $x->denominator();
Returns a copy of the denominator (the part under the line) as positive BigInt.
($n,$d) = $x->parts();
Return a list consisting of (signed) numerator and (unsigned) denominator as
BigInts.
$x = Math::BigRat->new('13/7');
print $x->as_int(),"\n"; # '1'
Returns a copy of the object as BigInt, truncated to an integer.
as_number() is an alias for as_int().
$x = Math::BigRat->new('13');
print $x->as_hex(),"\n"; # '0xd'
Returns the BigRat as hexadecimal string. Works only for integers.
$x = Math::BigRat->new('13');
print $x->as_bin(),"\n"; # '0x1101'
Returns the BigRat as binary string. Works only for integers.
$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.
Is not yet implemented.
Are not yet implemented.
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 $y.
print "$x is 1\n" if $x->is_one();
Return true if $x is exactly one, otherwise false.
print "$x is 0\n" if $x->is_zero();
Return true if $x is exactly zero, otherwise false.
print "$x is >= 0\n" if $x->is_positive();
Return true if $x is positive (greater than or equal to zero), otherwise
false. Please note that '+inf' is also positive, while 'NaN' and '-inf' aren't.
is_positive() is an alias for is_pos().
print "$x is < 0\n" if $x->is_negative();
Return true if $x is negative (smaller than zero), otherwise false. Please
note that '-inf' is also negative, while 'NaN' and '+inf' aren't.
is_negative() is an alias for is_neg().
print "$x is an integer\n" if $x->is_int();
Return true if $x has a denominator of 1 (e.g. no fraction parts), otherwise
false. Please note that '-inf', 'inf' and 'NaN' aren't integer.
print "$x is odd\n" if $x->is_odd();
Return true if $x is odd, otherwise false.
print "$x is even\n" if $x->is_even();
Return true if $x is even, otherwise false.
$x->bceil();
Set $x to the next bigger integer value (e.g. truncate the number to integer and then increment it by one).
$x->bfloor();
Truncate $x to an integer value.
$x->bsqrt();
Calculate the square root of $x.
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 acccuracy 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 RW above, anything else is
read-only.
Some things are not yet implemented, or only implemented half-way:
inf handling (partial) NaN handling (partial)
rounding (not implemented except for bceil/bfloor) $x ** $y where $y is not an integer bmod(), blog(), bmodinv() and bmodpow() (partial)
This program is free software; you may redistribute it and/or modify it under
the same terms as Perl itself.
the Math::BigFloat manpage and the Math::Big manpage as well as the Math::BigInt::BitVect manpage ,
the Math::BigInt::Pari manpage and the Math::BigInt::GMP manpage .
See http://search.cpan.org/search for a way to use
Math::BigRat.
The package at http://search.cpan.org/search
may contain more documentation and examples as well as testcases.
(C) by Tels http://bloodgate.com/ 2001 - 2005.
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