Matrix Computations On The CM-200

. The parallel computer CM-200 consists of a very large number of simple processors connected in a mesh. The peak performance is very high, but it is not clear how easy it is to write efficient programs in high-level languages. A straight-forward implementation of the Householder QR algorithm in CM Fortran is shown to be slow. Another implementation is presented, with better performance, but still not comparable to the low-level implementation in CMSSL. AMS Subject Classification : 65F05, 65F25, 65Y10 Key words: Connection Machine, Matrix Computations, QR-decomposition Matrix Computations on the CM-200 1 Introduction The Connection Machine 200 (CM) is a massively parallel SIMD computer, i.e. a computer with a very large number of simple processors, all executing the same stream of instruction simultaneously. The processors are connected in a hypercubelike structure. The machine was originally developed by Thinking Machines for AI and image processing. It has later been equipped with..