On Fri, Apr 5, 2019 at 7:19 AM Diogo FERREIRA SABINO via petsc-users < petsc-users@mcs.anl.gov> wrote:
> Hi, > I'm new in petsc and I'm trying to construct a MATNEST in two procs, by > setting each block of the nested matrix with a MATMPIAIJ matrix defined in > each proc. > I'm trying to use MatCreateNest or MatNestSetSubMats, but I'm not being > able to do it. > Using MatNestSetSubMats, I'm trying to construct the MATNEST, giving a > pointer to the correct matrices depending on the MPIrank of that proc. > I'm obtaining the error message for the line > :MatNestSetSubMats(AfullNEST,1,&IS_ROW,2,&IS_COL,AfullNESTpointer); > [0]PETSC ERROR: Invalid argument > [0]PETSC ERROR: Wrong type of object: Parameter # 5 > > Is there a way of doing it, or all the blocks of the MATNEST have to exist > in the same communicator as the MATNEST matrix? > Yes, they must all have the same communicator. A matrix can be empty on a process, so you just create them with the global communicator, set the local sizes that you want (eg, 0 on some procs). > A simple test is given below, lunching it with: mpirun -n 2 > ./Main_petsc.exe > > static char help[] = "Create MPI Nest"; > #include <petscmat.h> > > #undef __FUNCT__ > #define __FUNCT__ "main" > int main(int argc,char **argv) > { > PetscInitialize(&argc,&argv,(char*)0,help); > > ////////////////////////////////////////////////////////////////////////////// > PetscErrorCode ierr; > PetscMPIInt MPIrank,MPIsize; > MPI_Comm_rank(PETSC_COMM_WORLD,&MPIrank); > MPI_Comm_size(PETSC_COMM_WORLD,&MPIsize); > > //////////////////////////////////////////////////////// Create Each > Matrix: > Mat Adiag; > > //Create a Adiag different on each proc: > ierr = MatCreate(PETSC_COMM_SELF,&Adiag); > CHKERRQ(ierr); > ierr = MatSetSizes(Adiag,2,2,PETSC_DECIDE,PETSC_DECIDE); > CHKERRQ(ierr); > ierr = MatSetType(Adiag,MATMPIAIJ); > CHKERRQ(ierr); > ierr = MatSetFromOptions(Adiag); > CHKERRQ(ierr); > ierr = MatMPIAIJSetPreallocation(Adiag,2,NULL,2,NULL); > CHKERRQ(ierr); > > MatSetValue(Adiag,0,0,(MPIrank+5),INSERT_VALUES); > MatSetValue(Adiag,0,1,(MPIrank+10),INSERT_VALUES); > MatSetValue(Adiag,1,0,(MPIrank+15),INSERT_VALUES); > MatSetValue(Adiag,1,1,(MPIrank+20),INSERT_VALUES); > MatAssemblyBegin(Adiag,MAT_FINAL_ASSEMBLY); > MatAssemblyEnd(Adiag,MAT_FINAL_ASSEMBLY); > > /////////////////////////////////////////////////////////////// Create > Nest: > MPI_Barrier(PETSC_COMM_WORLD); > Mat AfullNEST, *AfullNESTpointer; > > PetscMalloc1(2,&AfullNESTpointer); > AfullNESTpointer[0]=NULL; > AfullNESTpointer[1]=NULL; > AfullNESTpointer[MPIrank]=Adiag; > // Rank=0 --> AfullNESTpointer[0]=Adiag; AfullNESTpointer[1]=NULL; > // Rank=1 --> AfullNESTpointer[0]=NULL; AfullNESTpointer[1]=Adiag; > > IS IS_ROW,IS_COL; > ISCreateStride(PETSC_COMM_SELF,1,MPIrank,0,&IS_ROW); > ISCreateStride(PETSC_COMM_SELF,2,0,1,&IS_COL); > // Rank=0 --> IS_ROW= [ 0 ] ; IS_COL= [ 0, 1 ] ; > // Rank=1 --> IS_ROW= [ 1 ] ; IS_COL= [ 0, 1 ] ; > > MatCreate(PETSC_COMM_WORLD,&AfullNEST); > MatSetSizes(AfullNEST,2,2,PETSC_DECIDE,PETSC_DECIDE); > // MatSetSizes(AfullNEST,PETSC_DECIDE,PETSC_DECIDE,4,4); > // > MatCreateNest(PETSC_COMM_WORLD,1,&IS_ROW,1,&IS_COL,AfullNESTpointer,&AfullNEST); > ierr = > MatNestSetSubMats(AfullNEST,1,&IS_ROW,2,&IS_COL,AfullNESTpointer); > CHKERRQ(ierr); > > ierr = PetscFinalize(); CHKERRQ(ierr); > return 0; > } >