  Among many existing algorithms, convergence methods are the most popular
means of computing square root and the reciprocal of square root of numbers. An
initial approximation is required in these methods. Look up tables (LUT) are
employed to produce the initial approximation. In this paper a number of
methods are suggested to reduce the size of the look up tables. The precision
of the initial approximation plays an important role in the quality of the
final result. There are constraints for the use of a LUT in terms of its size
and its access time. Therefore, the optimization of the LUTs must be done in a
way to minimize hardware while offering acceptable convergence speed and
exactitude.
