> El 31 may 2017, a las 21:46, Kannan, Ramakrishnan <kann...@ornl.gov> escribió: > > Hello, > > I have got a sparse 1D row distributed matrix in which every MPI process owns > an m/p x n of the global matrix mxn. I am running NHEP with krylovschur on > it. It is throwing me some wrong error. For your reference, I have attached > the modified ex5.c in which I SetSizes on the matrix to emulate the 1D row > distribution and the log file with the error. > > In the unmodified ex5.c, for m=5, N=15, the local_m and the local_n is 3x3. > How is the global 15x15 matrix distributed locally as 3x3 matrices? When I > print the global matrix, it doesn’t appear to be diagonal as well. > > If slepc doesn’t support sparse 1D row distributed matrix, how do I need to > redistribute it such that I can run NHEP on this. > -- > Regards, > Ramki > > <ex5.c><slepc.o607511>
As explained in the manpage, the local columns size n must match the local size of the x vector, so it must also be N/mpisize http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatSetSizes.html But be warned that your code will not work when N is not divisible by mpisize. In that case, global and local dimensions won't match. Setting local sizes is not necessary in your case, since by default PETSc is already doing a 1D block-row distribution. Jose
