As someone who is also working on this code, the problem is not uninitialized memory. Valgrind reports a clean bill of health.
On 01/02/2014 09:45 PM, Derek Gaston wrote: > This is almost definitely not a libMesh problem. It sounds like an > uninitialized variable. I recommend running your application using > valgrind ( http://valgrind.org ) . Use a debug (dbg) build of your > application and valgrind will point you right to the problem. > > Derek > > > On Thu, Jan 2, 2014 at 7:30 PM, Dafang Wang <[email protected]> wrote: > >> 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 >> > ------------------------------------------------------------------------------ > 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 ------------------------------------------------------------------------------ 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
