Patent ID: 6560623
Filing Date: 2003-05-06
Classification: G06F

Abstract:
A method of creating a numerical evaluator, the method comprising:(a) providing a plurality of operands x which produce results f(x) for a given function f(x) when using a rounding mode, the plurality of operands x and the results f(x) each being represented by a binary format having 48 or more total bits; (b) designing the numerical evaluator to approximate f(x) given at least one x value, the numerical evaluator having an error tolerance; (c) processing a set of the operands x using the numerical evaluator to obtain test results f(x); (d) checking the test results f(x) to determine if all the test results f(x) from the set of operands x were all properly rounded according to a predetermined standard result of the rounding mode in step (c); and (e) changing the numerical evaluator to have a different error tolerance and repeating steps (c) through (e) until no rounding errors are detected in step (d) whereby an optimal numerical evaluator is found.