Method to compute an approximation to the reciprocal of the square root of a floating point number in IEEE format

摘要

Approximations of reciprocal square roots are provided in IEEE floating point binary format by obtaining an index from an input value, accessing a pair of table values and performing a limited number of simple and rapidly performed manipulations. The maximum relative error in the approximation thus provided is less than 0.75/2^(2k+1) as compared with a maximum relative error of ½^k+2 of known methods, where 2^k is the number of table entries.