Actual source code: ex162.c

  1: static char help[] = "Tests MatShift for SeqAIJ matrices with some missing diagonal entries\n\n";

  3: #include <petscmat.h>

  5: int main(int argc, char **argv)
  6: {
  7:   Mat         A;
  8:   PetscInt    coli[4], row;
  9:   PetscScalar vali[4];
 10:   PetscMPIInt size;

 12:   PetscFunctionBeginUser;
 13:   PetscCall(PetscInitialize(&argc, &argv, (char *)0, help));
 14:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
 15:   PetscCheck(size == 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "This is a uniprocessor example only!");

 17:   PetscCall(MatCreate(PETSC_COMM_SELF, &A));
 18:   PetscCall(MatSetSizes(A, 4, 4, 4, 4));
 19:   PetscCall(MatSetType(A, MATSEQAIJ));
 20:   PetscCall(MatSeqAIJSetPreallocation(A, 4, NULL));

 22:   row     = 0;
 23:   coli[0] = 1;
 24:   coli[1] = 3;
 25:   vali[0] = 1.0;
 26:   vali[1] = 2.0;
 27:   PetscCall(MatSetValues(A, 1, &row, 2, coli, vali, ADD_VALUES));

 29:   row     = 1;
 30:   coli[0] = 0;
 31:   coli[1] = 1;
 32:   coli[2] = 2;
 33:   coli[3] = 3;
 34:   vali[0] = 3.0;
 35:   vali[1] = 4.0;
 36:   vali[2] = 5.0;
 37:   vali[3] = 6.0;
 38:   PetscCall(MatSetValues(A, 1, &row, 4, coli, vali, ADD_VALUES));

 40:   row     = 2;
 41:   coli[0] = 0;
 42:   coli[1] = 3;
 43:   vali[0] = 7.0;
 44:   vali[1] = 8.0;
 45:   PetscCall(MatSetValues(A, 1, &row, 2, coli, vali, ADD_VALUES));

 47:   PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
 48:   PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
 49:   PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));

 51:   PetscCall(MatShift(A, 0.0));
 52:   PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));

 54:   PetscCall(MatDestroy(&A));
 55:   PetscCall(PetscFinalize());
 56:   return 0;
 57: }

 59: /*TEST

 61:    test:

 63: TEST*/