bignum(3)
NAME
bignum - Transparent BigNumber support for Perl
SYNOPSIS
use bignum; $x = 2 + 4.5,"0; # BigFloat 6.5 print 2 ** 512 * 0.1; # really is what you think it is
DESCRIPTION
All operators (including basic math operations) are over
loaded. Integer and floating-point constants are created
as proper BigInts or BigFloats, respectively.
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:
- 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 -Mbignum=a,50 -le 'print sqrt(20)' - 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 -Mbignum=p,-50 -le 'print sqrt(20)' - t or trace
- This enables a trace mode and is primarily for debugging
bignum or Math::BigInt/Math::BigFloat. - l or lib
- Load a different math lib, see "MATH LIBRARY".
perl -Mbignum=l,GMP -e 'print 2 ** 512' - Currently there is no way to specify more than one
library on the command line. This will be hopefully
fixed soon ;) - v or version
- This prints out the name and version of all modules used
and then exits.
perl -Mbignum=v -e '' - MATH LIBRARY
- Math with the numbers is done (by default) by a module
called Math::BigInt::Calc. This is equivalent to saying:
use bignum lib => 'Calc';- You can change this by using:
use bignum 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 bignum lib => 'Foo,Math::BigInt::Bar';- Please see respective module documentation for further
details. - INTERNAL FORMAT
- The numbers are stored as objects, and their internals
might change at anytime, especially between math opera
tions. The objects also might belong to different classes,
like Math::BigInt, or Math::BigFLoat. Mixing them
together, even with normal scalars is not extraordinary,
but normal and expected. - You should not depend on the internal format, all accesses
must go through accessor methods. E.g. looking at
$x->{sign} is not a bright idea since there is no guaranty
that the object in question has such a hashkey, nor is a
hash underneath at all. - SIGN
- The sign is either '+', '-', 'NaN', '+inf' or '-inf' and
stored seperately. You can access it with the sign()
method. - 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. - METHODS
- Since all numbers are now objects, you can use all func
tions 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 it possible that the underly
ing object might morph into a different class than
BigFloat.
MODULES USED
"bignum" 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
EXAMPLES
- Some cool command line examples to impress the Python
crowd ;) - perl -Mbignum -le 'print sqrt(33)'
perl -Mbignum -le 'print 2*255'
perl -Mbignum -le 'print 4.5+2*255'
perl -Mbignum -le 'print 3/7 + 5/7 + 8/3'
perl -Mbignum -le 'print 123->is_odd()'
perl -Mbignum -le 'print log(2)'
perl -Mbignum -le 'print 2 ** 0.5'
perl -Mbignum=a,65 -le 'print 2 ** 0.2'
LICENSE
This program is free software; you may redistribute it
and/or modify it under the same terms as Perl itself.
SEE ALSO
Especially bigrat as in "perl -Mbigrat -le 'print
1/3+1/4'".
Math::BigFloat, Math::BigInt, Math::BigRat and Math::Big
as well as Math::BigInt::BitVect, Math::BigInt::Pari and
Math::BigInt::GMP.
AUTHORS
- (C) by Tels <http://bloodgate.com/> in early 2002.