Solution of large Hermitian eigenproblems on virtual and cache memory computers
Roy L. Streit · ACM SIGNUM Newsletter · 1981
The impact of cache and virtual memories on the performance of state-of-the-art software has not yet been fully explored. This letter documents the truth of this statement by presenting the results of a computational experiment performed on the VAX 11/780 (a computer possessing both these features) with well established and documented FORTRAN subroutines designed for high accuracy numerical solution of the ordinary Hermitian eigenproblem Az = λ z. Easily implemented changes in the storage allocation of the complex matrix A resulted in roughly half an order of magnitude improvement in both elapsed CPU and wall clock time, as well as in significantly improved overall system throughput. These changes do not affect the numerical algorithm in any way.