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.\" ========================================================================
.\"
.IX Title "bignum 3"
.TH bignum 3 "2002-11-24" "perl v5.8.0" "Perl Programmers Reference Guide"
.SH "NAME"
bignum \- Transparent BigNumber support for Perl
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&  use bignum;
.Ve
.PP
.Vb 2
\&  $x = 2 + 4.5,"\en";                    # BigFloat 6.5
\&  print 2 ** 512 * 0.1;                 # really is what you think it is
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
All operators (including basic math operations) are overloaded. Integer and
floating-point constants are created as proper BigInts or BigFloats,
respectively.
.Sh "\s-1OPTIONS\s0"
.IX Subsection "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:
.IP "a or accuracy" 2
.IX 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 \fIbround()\fR function for details.
.Sp
.Vb 1
\&        perl -Mbignum=a,50 -le 'print sqrt(20)'
.Ve
.IP "p or precision" 2
.IX 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 \fIbfround()\fR function for details.
.Sp
.Vb 1
\&        perl -Mbignum=p,-50 -le 'print sqrt(20)'
.Ve
.IP "t or trace" 2
.IX Item "t or trace"
This enables a trace mode and is primarily for debugging bignum or
Math::BigInt/Math::BigFloat.
.IP "l or lib" 2
.IX Item "l or lib"
Load a different math lib, see \*(L"\s-1MATH\s0 \s-1LIBRARY\s0\*(R".
.Sp
.Vb 1
\&        perl -Mbignum=l,GMP -e 'print 2 ** 512'
.Ve
.Sp
Currently there is no way to specify more than one library on the command
line. This will be hopefully fixed soon ;)
.IP "v or version" 2
.IX Item "v or version"
This prints out the name and version of all modules used and then exits.
.Sp
.Vb 1
\&        perl -Mbignum=v -e ''
.Ve
.Sh "\s-1MATH\s0 \s-1LIBRARY\s0"
.IX Subsection "MATH LIBRARY"
Math with the numbers is done (by default) by a module called
Math::BigInt::Calc. This is equivalent to saying:
.Sp
.Vb 1
\&        use bignum lib => 'Calc';
.Ve
.Sp
You can change this by using:
.Sp
.Vb 1
\&        use bignum lib => 'BitVect';
.Ve
.Sp
The following would first try to find Math::BigInt::Foo, then
Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
.Sp
.Vb 1
\&        use bignum lib => 'Foo,Math::BigInt::Bar';
.Ve
.Sp
Please see respective module documentation for further details.
.Sh "\s-1INTERNAL\s0 \s-1FORMAT\s0"
.IX Subsection "INTERNAL FORMAT"
The numbers are stored as objects, and their internals might change at anytime,
especially between math operations. 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.
.Sp
You should not depend on the internal format, all accesses must go through
accessor methods. E.g. looking at \f(CW$x\fR\->{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.
.Sh "\s-1SIGN\s0"
.IX Subsection "SIGN"
The sign is either '+', '\-', 'NaN', '+inf' or '\-inf' and stored seperately.
You can access it with the \fIsign()\fR method.
.Sp
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.
.Sh "\s-1METHODS\s0"
.IX Subsection "METHODS"
Since all numbers are now objects, you can use all functions that are part of
the BigInt or BigFloat \s-1API\s0. It is wise to use only the \fIbxxx()\fR notation, and not
the \fIfxxx()\fR notation, though. This makes it possible that the underlying object
might morph into a different class than BigFloat.
.SH "MODULES USED"
.IX Header "MODULES USED"
\&\f(CW\*(C`bignum\*(C'\fR 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.
.Sp
The following modules are currently used by bignum:
.Sp
.Vb 3
\&        Math::BigInt::Lite      (for speed, and only if it is loadable)
\&        Math::BigInt
\&        Math::BigFloat
.Ve
.SH "EXAMPLES"
.IX Header "EXAMPLES"
Some cool command line examples to impress the Python crowd ;)
.Sp
.Vb 8
\&        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'
.Ve
.SH "LICENSE"
.IX Header "LICENSE"
This program is free software; you may redistribute it and/or modify it under
the same terms as Perl itself.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
Especially bigrat as in \f(CW\*(C`perl \-Mbigrat \-le 'print 1/3+1/4'\*(C'\fR.
.Sp
Math::BigFloat, Math::BigInt, Math::BigRat and Math::Big as well
as Math::BigInt::BitVect, Math::BigInt::Pari and  Math::BigInt::GMP.
.SH "AUTHORS"
.IX Header "AUTHORS"
(C) by Tels <http://bloodgate.com/> in early 2002.

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