1: static const char help[] = "Test parallel assembly of SBAIJ matrices\n\n";

  3:  #include <petscmat.h>

  5: PetscErrorCode Assemble(MPI_Comm comm,PetscInt n,MatType mtype)
  6: {
  7:   Mat            A;
  8:   PetscInt       first,last,i;
 10:   PetscMPIInt    rank,size;

 13:   MatCreate(PETSC_COMM_WORLD,&A);
 14:   MatSetSizes(A, PETSC_DECIDE,PETSC_DECIDE,n,n);
 15:   MatSetType(A,MATMPISBAIJ);
 16:   MatSetFromOptions(A);
 17:   MPI_Comm_size(comm,&size);
 18:   MPI_Comm_rank(comm,&rank);
 19:   if (rank < size-1) {
 20:     MatMPISBAIJSetPreallocation(A,1,1,NULL,1,NULL);
 21:   } else {
 22:     MatMPISBAIJSetPreallocation(A,1,2,NULL,0,NULL);
 23:   }
 24:   MatGetOwnershipRange(A,&first,&last);
 25:   MatSetOption(A,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_TRUE);
 26:   last--;
 27:   for (i=first; i<=last; i++) {
 28:     MatSetValue(A,i,i,2.,INSERT_VALUES);
 29:     if (i != n-1) {MatSetValue(A,i,n-1,-1.,INSERT_VALUES);}
 30:   }
 31:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
 32:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
 33:   MatDestroy(&A);
 34:   return(0);
 35: }

 37: int main(int argc,char *argv[])
 38: {
 40:   MPI_Comm       comm;
 41:   PetscInt       n = 6;

 43:   PetscInitialize(&argc,&argv,NULL,help);if (ierr) return ierr;
 44:   comm = PETSC_COMM_WORLD;
 45:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 46:   Assemble(comm,n,MATMPISBAIJ);
 47:   PetscFinalize();
 48:   return ierr;
 49: }


 52: /*TEST

 54:    test:
 55:       nsize: 4
 56:       args: -n 1000 -mat_view ascii::ascii_info_detail
 57:       requires: double !complex !define(PETSC_USE_64BIT_INDICES)

 59: TEST*/