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.\" ========================================================================
.\"
.IX Title "bigint 3"
.TH bigint 3 "2002-11-24" "perl v5.8.0" "Perl Programmers Reference Guide"
.SH "NAME"
bigint \- Transparent big integer support for Perl
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&  use bignt;
.Ve
.PP
.Vb 2
\&  $x = 2 + 4.5,"\en";                    # BigInt 6
\&  print 2 ** 512;                       # really is what you think it is
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
All operators (including basic math operations) are overloaded. Integer
constants are created as proper BigInts.
.PP
Floating point constants are truncated to integer. All results are also
trunctaed.
.Sh "\s-1OPTIONS\s0"
.IX Subsection "OPTIONS"
bigint 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 -Mbigint=a,2 -le 'print 12345+1'
.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, and
are <B>ignored</B> since all operations happen in integer space.
A positive value rounds to this digit left from the dot. 0 or 1 mean round to
integer and are ignore like negative values.
.Sp
See Math::BigInt's \fIbfround()\fR function for details.
.Sp
.Vb 1
\&        perl -Mbignum=p,5 -le 'print 123456789+123'
.Ve
.IP "t or trace" 2
.IX Item "t or trace"
This enables a trace mode and is primarily for debugging bigint or
Math::BigInt.
.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 -Mbigint=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 -Mbigint=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 bigint lib => 'Calc';
.Ve
.Sp
You can change this by using:
.Sp
.Vb 1
\&        use bigint 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 bigint 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::BigInt::Lite. 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 hash key, 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 \s-1API\s0. You can only use the \fIbxxx()\fR notation, and not the \fIfxxx()\fR
notation, though. 
.SH "MODULES USED"
.IX Header "MODULES USED"
\&\f(CW\*(C`bigint\*(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 bigint:
.Sp
.Vb 2
\&        Math::BigInt::Lite      (for speed, and only if it is loadable)
\&        Math::BigInt
.Ve
.SH "EXAMPLES"
.IX Header "EXAMPLES"
Some cool command line examples to impress the Python crowd ;) You might want
to compare them to the results under \-Mbignum or \-Mbigrat:
.Sp
.Vb 8
\&        perl -Mbigint -le 'print sqrt(33)'
\&        perl -Mbigint -le 'print 2*255'
\&        perl -Mbigint -le 'print 4.5+2*255'
\&        perl -Mbigint -le 'print 3/7 + 5/7 + 8/3'
\&        perl -Mbigint -le 'print 123->is_odd()'
\&        perl -Mbigint -le 'print log(2)'
\&        perl -Mbigint -le 'print 2 ** 0.5'
\&        perl -Mbigint=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 and
bignum as in \f(CW\*(C`perl \-Mbignum \-le 'print sqrt(2)'\*(C'\fR.
.Sp
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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