Returns an array whose first element contains the quotient and whose second element contains the "common residue". If the remainder would be positive, the "common residue" and the remainder are the same. If the remainder would be negative, the "common residue" is equal to the sum of the remainder and the divisor (basically, the "common residue" is the first positive modulo).
Calculates the greatest common divisor and Bezout's identity.
Say you have 693 and 609. The GCD is 21. Bezout's identity states that there exist integers x and y such that 693*x + 609*y == 21. In point of fact, there are actually an infinite number of x and y combinations and which combination is returned is dependant upon which mode is in use. See Bezout's identity - Wikipedia for more information.
Assuming the $t parameter is not set, this function has an error rate of 2**-80. The main motivation for the $t parameter is distributability. Math_BigInteger::randomPrime() can be distributed accross multiple pageloads on a website instead of just one.
Although you can call Math_BigInteger::__toString() directly in PHP5, you cannot call Math_BigInteger::__clone() directly in PHP5. You can in PHP4 since it's not a magic method, but in PHP5, you have to call it by using the PHP5 only syntax of $y = clone $x. As such, if you're trying to write an application that works on both PHP4 and PHP5, call Math_BigInteger::copy(), instead.