Could anyone help me with this one please? How could I copy the contents of a serial matrix into a parallel matrix? Would having a dof_map help me in this process? How could I build one?
Miguel On Fri, Aug 29, 2014 at 9:32 AM, Miguel Angel Salazar de Troya < [email protected]> wrote: > I started parallelizing my code. I have part of the code that is serial > because I need to have access to the whole mesh. In this part of the code, > I build a PetscMatrix. Once I'm done building it (in serial), I would like > to scatter it through the other processors. > > Now, given that I built the PetscMatrix in serial (the local dimensions > are the same than the global dimensions) I assume I should build another > matrix with local dimensions in parallel. I need to set this size equal to > a solution vector in one of my systems (that's what I found here, > http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatSetSizes.html) > If this system is called "densities", will I just set it equal > to densities.solution->local_size()? > > Once the local dimensions are set, I need to copy the contents. Because > the original matrix is run in serial in all the processors, I wouldn't need > to make any communication, right? I would copy the matrix value by value, > or there is a better way to do this? > > Thanks in advance > Miguel > > > On Thu, Aug 28, 2014 at 9:45 PM, Miguel Angel Salazar de Troya < > [email protected]> wrote: > >> Yeah, it says 4. I think I will try to parallelize my code with MPI to >> get better performance. >> >> >> On Thu, Aug 28, 2014 at 9:10 PM, Roy Stogner <[email protected]> >> wrote: >> >>> >>> >>> On Thu, 28 Aug 2014, Miguel Angel Salazar de Troya wrote: >>> >>> How can I give one MPI rank per shared-memory system in my own >>>> computer? I thought that running the program in serial with the >>>> option "--n_threads=4" would work, but it doesn't seem so. >>>> >>> >>> On a single computer, no clustering, that should have been sufficient. >>> >>> Do you have a mesh.print_info() in your app, and if so what does it >>> say n_threads is? >>> >>> If it says n_threads is 1, is it possible that you configured without >>> TBB installed? >>> >>> >>> It might be that the rest of my code that is not "threaded" is too >>>> slow. >>>> >>> >>> Yes, or it might be possible that the unthreaded parts of our code are >>> too slow. Getting the algebraic solver to run multithreaded is >>> tricky, and in a lot of codes the solve is the expensive part. >>> --- >>> Roy >> >> >> >> >> -- >> *Miguel Angel Salazar de Troya* >> >> Graduate Research Assistant >> Department of Mechanical Science and Engineering >> University of Illinois at Urbana-Champaign >> (217) 550-2360 >> [email protected] >> >> > > > -- > *Miguel Angel Salazar de Troya* > Graduate Research Assistant > Department of Mechanical Science and Engineering > University of Illinois at Urbana-Champaign > (217) 550-2360 > [email protected] > > -- *Miguel Angel Salazar de Troya* Graduate Research Assistant Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign (217) 550-2360 [email protected] ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that matters. http://tv.slashdot.org/ _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
