bigrat(3pm)

1bigrat(3pm)            Perl Programmers Reference Guide            bigrat(3pm)
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NAME

6       bigrat - Transparent BigNumber/BigRational support for Perl
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SYNOPSIS

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

15       All operators (inlcuding basic math operations) are overloaded. Integer
16       and floating-point constants are created as proper BigInts or
17       BigFloats, respectively.
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19       Other than bignum, this module upgrades to Math::BigRat, meaning that
20       instead of 2.5 you will get 2+1/2 as output.
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22       Modules Used
23
24       "bigrat" is just a thin wrapper around various modules of the
25       Math::BigInt family. Think of it as the head of the family, who runs
26       the shop, and orders the others to do the work.
27
28       The following modules are currently used by bignum:
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30               Math::BigInt::Lite      (for speed, and only if it is loadable)
31               Math::BigInt
32               Math::BigFloat
33               Math::BigRat
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35       Math Library
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37       Math with the numbers is done (by default) by a module called
38       Math::BigInt::Calc. This is equivalent to saying:
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40               use bigrat lib => 'Calc';
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42       You can change this by using:
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44               use bigrat lib => 'BitVect';
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46       The following would first try to find Math::BigInt::Foo, then
47       Math::BigInt::Bar, and when this also fails, revert to Math::Big‐
48       Int::Calc:
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50               use bigrat lib => 'Foo,Math::BigInt::Bar';
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52       Please see respective module documentation for further details.
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54       Sign
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56       The sign is either '+', '-', 'NaN', '+inf' or '-inf'.
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58       A sign of 'NaN' is used to represent the result when input arguments
59       are not numbers or as a result of 0/0. '+inf' and '-inf' represent plus
60       respectively minus infinity. You will get '+inf' when dividing a posi‐
61       tive number by 0, and '-inf' when dividing any negative number by 0.
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63       Methods
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65       Since all numbers are not objects, you can use all functions that are
66       part of the BigInt or BigFloat API. It is wise to use only the bxxx()
67       notation, and not the fxxx() notation, though. This makes you inde‐
68       pended on the fact that the underlying object might morph into a dif‐
69       ferent class than BigFloat.
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71       Cavaet
72
73       But a warning is in order. When using the following to make a copy of a
74       number, only a shallow copy will be made.
75
76               $x = 9; $y = $x;
77               $x = $y = 7;
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79       If you want to make a real copy, use the following:
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81               $y = $x->copy();
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83       Using the copy or the original with overloaded math is okay, e.g. the
84       following work:
85
86               $x = 9; $y = $x;
87               print $x + 1, " ", $y,"\n";     # prints 10 9
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89       but calling any method that modifies the number directly will result in
90       both the original and the copy beeing destroyed:
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92               $x = 9; $y = $x;
93               print $x->badd(1), " ", $y,"\n";        # prints 10 10
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95               $x = 9; $y = $x;
96               print $x->binc(1), " ", $y,"\n";        # prints 10 10
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98               $x = 9; $y = $x;
99               print $x->bmul(2), " ", $y,"\n";        # prints 18 18
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101       Using methods that do not modify, but testthe contents works:
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103               $x = 9; $y = $x;
104               $z = 9 if $x->is_zero();                # works fine
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106       See the documentation about the copy constructor and "=" in overload,
107       as well as the documentation in BigInt for further details.
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109       Options
110
111       bignum recognizes some options that can be passed while loading it via
112       use.  The options can (currently) be either a single letter form, or
113       the long form.  The following options exist:
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115       a or accuracy
116         This sets the accuracy for all math operations. The argument must be
117         greater than or equal to zero. See Math::BigInt's bround() function
118         for details.
119
120                 perl -Mbigrat=a,50 -le 'print sqrt(20)'
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122       p or precision
123         This sets the precision for all math operations. The argument can be
124         any integer. Negative values mean a fixed number of digits after the
125         dot, while a positive value rounds to this digit left from the dot. 0
126         or 1 mean round to integer. See Math::BigInt's bfround() function for
127         details.
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129                 perl -Mbigrat=p,-50 -le 'print sqrt(20)'
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131       t or trace
132         This enables a trace mode and is primarily for debugging bignum or
133         Math::BigInt/Math::BigFloat.
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135       l or lib
136         Load a different math lib, see "MATH LIBRARY".
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138                 perl -Mbigrat=l,GMP -e 'print 2 ** 512'
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140         Currently there is no way to specify more than one library on the
141         command line. This will be hopefully fixed soon ;)
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143       v or version
144         This prints out the name and version of all modules used and then
145         exits.
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147                 perl -Mbigrat=v
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EXAMPLES

150               perl -Mbigrat -le 'print sqrt(33)'
151               perl -Mbigrat -le 'print 2*255'
152               perl -Mbigrat -le 'print 4.5+2*255'
153               perl -Mbigrat -le 'print 3/7 + 5/7 + 8/3'
154               perl -Mbigrat -le 'print 12->is_odd()';
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LICENSE

157       This program is free software; you may redistribute it and/or modify it
158       under the same terms as Perl itself.
159

AUTHORS

167       (C) by Tels <http://bloodgate.com/> in early 2002 - 2005.
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171perl v5.8.8                       2001-09-21                       bigrat(3pm)

NAME

SYNOPSIS

DESCRIPTION

EXAMPLES

LICENSE

SEE ALSO

AUTHORS