Dear Siesta Developers Team and Users, I would like to show positive information of the parallel Siesta code. Recently, I have installed a low latency communication software GAMMA (Genoa Active Message Machine) to my Beowulf cluster machine of Pentium 4 (3.0GHz), and measured timing of the parallel Siesta code v1.3.
The results for a 181 atom system (slab /gamma point) tell us that there is a massive communication overhead when TCP/IP is used with Siesta. This overhead is almost completely slashed by means of the low latency communication software (only with small additional cost for the second Gigabit network). Furthermore, I have used Portland's c/Fortran compilers with GAMMA, where the parallel Siesta is found to scale reasonably well. The speedup ratio in comparison with the uni-processor case is 3 for four processors, and is about 4.5 for eight processors. (This may depend on the problem size). These timing results and the method of introducing the GAMMA system are shown at http://dphysique.nifs.ac.jp/. Click on "PC Cluster with High-Speed Communication $B!I (B; the first of two PDF files is written in English. Sincerely yours, Motohiko Tanaka *********************************** Coordinated Research Center Institute for Fusion Science Toki 509-5292, Japan Email: [EMAIL PROTECTED] URL: http://dphysique.nifs.ac.jp/ ***********************************
