MirOS Manual: Math::BigInt::Calc(3p)


Math::BigInt::CalPerl)Programmers ReferenceMath::BigInt::Calc(3p)

NAME

     Math::BigInt::Calc - Pure Perl module to support
     Math::BigInt

SYNOPSIS

     Provides support for big integer calculations. Not intended
     to be used by other modules. Other modules which sport the
     same functions can also be used to support Math::BigInt,
     like Math::BigInt::GMP or Math::BigInt::Pari.

DESCRIPTION

     In order to allow for multiple big integer libraries,
     Math::BigInt was rewritten to use library modules for core
     math routines. Any module which follows the same API as this
     can be used instead by using the following:

             use Math::BigInt lib => 'libname';

     'libname' is either the long name ('Math::BigInt::Pari'), or
     only the short version like 'Pari'.

STORAGE

METHODS

     The following functions MUST be defined in order to support
     the use by Math::BigInt v1.70 or later:

             api_version()   return API version, minimum 1 for v1.70
             _new(string)    return ref to new object from ref to decimal string
             _zero()         return a new object with value 0
             _one()          return a new object with value 1
             _two()          return a new object with value 2
             _ten()          return a new object with value 10

             _str(obj)       return ref to a string representing the object
             _num(obj)       returns a Perl integer/floating point number
                             NOTE: because of Perl numeric notation defaults,
                             the _num'ified obj may lose accuracy due to
                             machine-dependend floating point size limitations

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             _add(obj,obj)   Simple addition of two objects
             _mul(obj,obj)   Multiplication of two objects
             _div(obj,obj)   Division of the 1st object by the 2nd
                             In list context, returns (result,remainder).
                             NOTE: this is integer math, so no
                             fractional part will be returned.
                             The second operand will be not be 0, so no need to
                             check for that.
             _sub(obj,obj)   Simple subtraction of 1 object from another
                             a third, optional parameter indicates that the params
                             are swapped. In this case, the first param needs to
                             be preserved, while you can destroy the second.
                             sub (x,y,1) => return x - y and keep x intact!
             _dec(obj)       decrement object by one (input is garant. to be > 0)
             _inc(obj)       increment object by one

             _acmp(obj,obj)  <=> operator for objects (return -1, 0 or 1)

             _len(obj)       returns count of the decimal digits of the object
             _digit(obj,n)   returns the n'th decimal digit of object

             _is_one(obj)    return true if argument is 1
             _is_two(obj)    return true if argument is 2
             _is_ten(obj)    return true if argument is 10
             _is_zero(obj)   return true if argument is 0
             _is_even(obj)   return true if argument is even (0,2,4,6..)
             _is_odd(obj)    return true if argument is odd (1,3,5,7..)

             _copy           return a ref to a true copy of the object

             _check(obj)     check whether internal representation is still intact
                             return 0 for ok, otherwise error message as string

             _from_hex(str)  return ref to new object from ref to hexadecimal string
             _from_bin(str)  return ref to new object from ref to binary string

             _as_hex(str)    return string containing the value as
                             unsigned hex string, with the '0x' prepended.
                             Leading zeros must be stripped.
             _as_bin(str)    Like as_hex, only as binary string containing only
                             zeros and ones. Leading zeros must be stripped and a
                             '0b' must be prepended.

             _rsft(obj,N,B)  shift object in base B by N 'digits' right
             _lsft(obj,N,B)  shift object in base B by N 'digits' left

             _xor(obj1,obj2) XOR (bit-wise) object 1 with object 2
                             Note: XOR, AND and OR pad with zeros if size mismatches
             _and(obj1,obj2) AND (bit-wise) object 1 with object 2
             _or(obj1,obj2)  OR (bit-wise) object 1 with object 2

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             _mod(obj,obj)   Return remainder of div of the 1st by the 2nd object
             _sqrt(obj)      return the square root of object (truncated to int)
             _root(obj)      return the n'th (n >= 3) root of obj (truncated to int)
             _fac(obj)       return factorial of object 1 (1*2*3*4..)
             _pow(obj,obj)   return object 1 to the power of object 2
                             return undef for NaN
             _zeros(obj)     return number of trailing decimal zeros
             _modinv         return inverse modulus
             _modpow         return modulus of power ($x ** $y) % $z
             _log_int(X,N)   calculate integer log() of X in base N
                             X >= 0, N >= 0 (return undef for NaN)
                             returns (RESULT, EXACT) where EXACT is:
                              1     : result is exactly RESULT
                              0     : result was truncated to RESULT
                              undef : unknown whether result is exactly RESULT
             _gcd(obj,obj)   return Greatest Common Divisor of two objects

     The following functions are optional, and can be defined if
     the underlying lib has a fast way to do them. If undefined,
     Math::BigInt will use pure Perl (hence slow) fallback rou-
     tines to emulate these:

             _signed_or
             _signed_and
             _signed_xor

     Input strings come in as unsigned but with prefix (i.e. as
     '123', '0xabc' or '0b1101').

     So the library needs only to deal with unsigned big
     integers. Testing of input parameter validity is done by the
     caller, so you need not worry about underflow (f.i. in
     "_sub()", "_dec()") nor about division by zero or similar
     cases.

     The first parameter can be modified, that includes the pos-
     sibility that you return a reference to a completely dif-
     ferent object instead. Although keeping the reference and
     just changing it's contents is prefered over creating and
     returning a different reference.

     Return values are always references to objects, strings, or
     true/false for comparisation routines.

WRAP YOUR OWN

     If you want to port your own favourite c-lib for big numbers
     to the Math::BigInt interface, you can take any of the
     already existing modules as a rough guideline. You should
     really wrap up the latest BigInt and BigFloat testsuites
     with your module, and replace in them any of the following:

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Math::BigInt::CalPerl)Programmers ReferenceMath::BigInt::Calc(3p)

             use Math::BigInt;

     by this:

             use Math::BigInt lib => 'yourlib';

     This way you ensure that your library really works 100%
     within Math::BigInt.

LICENSE

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

AUTHORS

     Original math code by Mark Biggar, rewritten by Tels
     <http://bloodgate.com/> in late 2000. Seperated from BigInt
     and shaped API with the help of John Peacock.

     Fixed, speed-up, streamlined and enhanced by Tels 2001 -
     2005.

SEE ALSO

     Math::BigInt, Math::BigFloat, Math::BigInt::BitVect,
     Math::BigInt::GMP, Math::BigInt::FastCalc and
     Math::BigInt::Pari.

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