
gcd(+Number1, +Number2, -U, -V, -GCD)

   Unifies GCD with the Greatest Common Divisor of
	Number1 and Number2, and gives appropriate coefficients U and
	V for the corresponding Bezout equation

Arguments
   Number1             Integer.
   Number2             Integer.
   U                   Output: integer.
   V                   Output: integer.
   GCD                 Output: integer.

Type
   Arithmetic

Description

   The Greatest Common Divisor operation is only defined on integer arguments.

   In coroutining mode, if Number1 or Number2 are uninstantiated, the call
   is delayed until these variables are instantiated.

   The Bezout equation is Number1*U + Number2*V = GCD.  These
   coefficients are calculated by an extended version of Euclid's
   algorithm.




Modes and Determinism
   gcd(+, +, -, -, -) is det

Exceptions
     4 --- Number1 or Number2 is not instantiated (non-coroutining mode    only).
     5 --- Number1 or Number2 is a number but not an integer.
    24 --- Number1 or Number2 is not of a numeric type.

Examples
   
Success:
      gcd(9, 15, 2, -1, 3).
      gcd(-9, 15, -2, -1, 3).
      gcd(2358352782,97895234896224,U,V,G).  % gives U = 2130001290117, V = -51312962, G = 6 

Error:
      gcd(A, 2, U, V, G).           (Error 4).
      gcd(1.0, 2, U, V, G).         (Error 5).
      gcd(4 + 2, 2, U, V, G).       (Error 24).


See Also
   gcd / 3, lcm / 3, is / 2
