Parallel algorithms for reduction of a symmetric matrix to tridiagonal form on a shared memory multiprocessor

Empirical comparison was carried out using C++ and the THREADS package on a shared memory Encore Multimax multiprocessor [Encore Computer Corporation, Encore Parallel Threads Manual No. 724-06210 Rev. A, 1988]. In this testing the final version which involves most overlap was found to be the most efficient algorithm, and its efficiency is very high when the algorithm has some minor changes did give some improvements.