Hi, My libmesh progam, which uses SNES to solve a nonlinear equation, had different convergence behavior when running on a linux desktop and on a cluster machine.
All other running conditions were double checked to be identical: It was the same program running as a single thread on both machines. Both machines were using Libmesh 0.9.2.2. My program was solving a simple elastic model with good numerical/physical behavior. (The model consists of a 5*5*5 cubic mesh with a total of ~600 degress of freedom.) For the nonlinear solve, I was using the Newton method and line search (the default settings in Petsc SNES). The Newton method took 5 iterations to converge on my desktop (Ubutun 12.04), whereas it took 114 iterations to converge on the cluster. Moreover, both machines generated identical results in the first 2 Newton iterations, then they diverged from the 3rd iteration. I am wondering if such difference is common for Libmesh/Petsc programs running on different machines. Does anyone have similar experience of running programs on different clusters? Thanks, Dafang -- Dafang Wang, Ph.D. Postdoctoral Fellow Institute of Computational Medicine Hackerman Hall, Room 218 Johns Hopkins University, Baltimore, 21218 http://lagniappe.icm.jhu.edu/~dwang/ ------------------------------------------------------------------------------ Rapidly troubleshoot problems before they affect your business. Most IT organizations don't have a clear picture of how application performance affects their revenue. With AppDynamics, you get 100% visibility into your Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics Pro! http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
