MirOS Manual: Math::BigRat(3p)


Math::BigRat(3p)Perl Programmers Reference Guide Math::BigRat(3p)

NAME

     Math::BigRat - Arbitrary big rational numbers

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();

DESCRIPTION

     Math::BigRat complements Math::BigInt and Math::BigFloat by
     providing support for arbitrary big rational numbers.

     MATH LIBRARY

     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 documen-
     tation 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

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METHODS

     Any methods not listed here are dervied from Math::BigFloat
     (or Math::BigInt), so make sure you check these two modules
     for further information.

     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

     numerator()

             $n = $x->numerator();

     Returns a copy of the numerator (the part above the line) as
     signed BigInt.

     denominator()

             $d = $x->denominator();

     Returns a copy of the denominator (the part under the line)
     as positive BigInt.

     parts()

             ($n,$d) = $x->parts();

     Return a list consisting of (signed) numerator and
     (unsigned) denominator as BigInts.

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     as_int()

             $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()".

     as_hex()

             $x = Math::BigRat->new('13');
             print $x->as_hex(),"\n";                # '0xd'

     Returns the BigRat as hexadecimal string. Works only for
     integers.

     as_bin()

             $x = Math::BigRat->new('13');
             print $x->as_bin(),"\n";                # '0x1101'

     Returns the BigRat as binary string. Works only for
     integers.

     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.

     blog()

     Is not yet implemented.

     bround()/round()/bfround()

     Are not yet implemented.

     bmod()

             use Math::BigRat;
             my $x = Math::BigRat->new('7/4');
             my $y = Math::BigRat->new('4/3');
             print $x->bmod($y);

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     Set $x to the remainder of the division of $x by $y.

     is_one()

             print "$x is 1\n" if $x->is_one();

     Return true if $x is exactly one, otherwise false.

     is_zero()

             print "$x is 0\n" if $x->is_zero();

     Return true if $x is exactly zero, otherwise false.

     is_pos()

             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()".

     is_neg()

             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()".

     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.

     is_odd()

             print "$x is odd\n" if $x->is_odd();

     Return true if $x is odd, otherwise false.

     is_even()

             print "$x is even\n" if $x->is_even();

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     Return true if $x is even, otherwise false.

     bceil()

             $x->bceil();

     Set $x to the next bigger integer value (e.g. truncate the
     number to integer and then increment it by one).

     bfloor()

             $x->bfloor();

     Truncate $x to an integer value.

     bsqrt()

             $x->bsqrt();

     Calculate the square root of $x.

     config

             use Data::Dumper;

             print Dumper ( Math::BigRat->config() );
             print Math::BigRat->config()->{lib},"\n";

     Returns a hash containing the configuration, e.g. the ver-
     sion number, lib loaded etc. The following hash keys are
     currently filled in with the appropriate information.

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             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 configura-
     tion values. This works only for values that a marked with a
     "RW" above, anything else is read-only.

BUGS

     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)

LICENSE

     This program is free software; you may redistribute it
     and/or modify it under the same terms as Perl itself.

SEE ALSO

     Math::BigFloat and Math::Big as well as
     Math::BigInt::BitVect, Math::BigInt::Pari and
     Math::BigInt::GMP.

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     See <http://search.cpan.org/search?dist=bignum> for a way to
     use Math::BigRat.

     The package at
     <http://search.cpan.org/search?dist=Math%3A%3ABigRat> may
     contain more documentation and examples as well as test-
     cases.

AUTHORS

     (C) by Tels <http://bloodgate.com/> 2001 - 2005.

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