Apparatus and method useful for evaluating periodic functions

摘要

A computer and a method of using the computer to reduce an original argument to obtain a periodic function of the argument. A special number Pj is employed that is close to a nontrivial even-integral multiple pi . The technique subtracts a non-negative integral multiple of Pj from the original argument to obtain a first reduced argument. Then, a second non-negative integer multiple of a floating-point representation of +E,fra pi /2+EE is subtracted from the first reduced argument to obtain a second reduced argument. Next, a periodic function of a third argument equal to a sum of the second reduced argument plus the product of the first non-negative integral multiple and a floating-point representation of an offset delta j is evaluated to obtain a result.