With regard to weather codes. I looked at a program for local forecasting. Just six or eight computational nodes are used. The grid of physical data is not very dense because the initial conditions do not have high spatial resolution. The consequence is that each subdomain has alot of surface area, that is, alot of communication. Moreover, there are many variables, temperature and pressure for diffusion, momentum and pressure for convection, humidity and ground conditions. The typical structure is a simple finite-difference block then exchange of data, then a finite-difference block on another group of variables and on and on. There is no "kernel" of calculation but rather the code is "flat". The result is that alot of time is spent waiting for the exchange of data at the boundaries of subdomains on different compute nodes.
Best regards, Alan Scheinine Centro di Ricerca, Sviluppo e Studi Superiori in Sardegna Center for Advanced Studies, Research, and Development in Sardinia Postal Address: | Physical Address for FedEx, UPS, DHL: --------------- | ------------------------------------- Alan Scheinine | Alan Scheinine c/o CRS4 | c/o CRS4 C.P. n. 25 | Loc. Pixina Manna Edificio 1 09010 Pula (Cagliari), Italy | 09010 Pula (Cagliari), Italy Email: [EMAIL PROTECTED] Phone: 070 9250 238 [+39 070 9250 238] Fax: 070 9250 216 or 220 [+39 070 9250 216 or +39 070 9250 220] Operator at reception: 070 9250 1 [+39 070 9250 1] Mobile phone: 347 7990472 [+39 347 7990472] _______________________________________________ Beowulf mailing list, [email protected] To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
