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bignum(3)


NAME

  bignum - Transparent BigNumber support for Perl


SYNOPSIS

    use bignum;

    $x = 2 + 4.5,"\n";			  # BigFloat 6.5
    print 2 ** 512 * 0.1;		  # really is what you think it is


DESCRIPTION

  All operators (including basic math operations) are overloaded. 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 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.

  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 functions 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
  underlying 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.

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