Actual source code: ex64.c

  1: static char help[] = "Saves 4by4 block matrix.\n\n";

  3: #include <petscmat.h>

  5: int main(int argc, char **args)
  6: {
  7:   Mat         A;
  8:   PetscInt    i, j;
  9:   PetscMPIInt size;
 10:   PetscViewer fd;
 11:   PetscScalar values[16], one = 1.0;
 12:   Vec         x;

 14:   PetscFunctionBeginUser;
 15:   PetscCall(PetscInitialize(&argc, &args, NULL, help));
 16:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
 17:   PetscCheck(size == 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, m "Can only run on one processor");

 19:   /*
 20:      Open binary file.  Note that we use FILE_MODE_WRITE to indicate
 21:      writing to this file.
 22:   */
 23:   PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD, "4by4", FILE_MODE_WRITE, &fd));

 25:   PetscCall(MatCreateSeqBAIJ(PETSC_COMM_WORLD, 4, 12, 12, 0, 0, &A));

 27:   for (i = 0; i < 16; i++) values[i] = i;
 28:   for (i = 0; i < 4; i++) values[4 * i + i] += 5;
 29:   i = 0;
 30:   j = 0;
 31:   PetscCall(MatSetValuesBlocked(A, 1, &i, 1, &j, values, INSERT_VALUES));

 33:   for (i = 0; i < 16; i++) values[i] = i;
 34:   i = 0;
 35:   j = 2;
 36:   PetscCall(MatSetValuesBlocked(A, 1, &i, 1, &j, values, INSERT_VALUES));

 38:   for (i = 0; i < 16; i++) values[i] = i;
 39:   i = 1;
 40:   j = 0;
 41:   PetscCall(MatSetValuesBlocked(A, 1, &i, 1, &j, values, INSERT_VALUES));

 43:   for (i = 0; i < 16; i++) values[i] = i;
 44:   for (i = 0; i < 4; i++) values[4 * i + i] += 6;
 45:   i = 1;
 46:   j = 1;
 47:   PetscCall(MatSetValuesBlocked(A, 1, &i, 1, &j, values, INSERT_VALUES));

 49:   for (i = 0; i < 16; i++) values[i] = i;
 50:   i = 2;
 51:   j = 0;
 52:   PetscCall(MatSetValuesBlocked(A, 1, &i, 1, &j, values, INSERT_VALUES));

 54:   for (i = 0; i < 16; i++) values[i] = i;
 55:   for (i = 0; i < 4; i++) values[4 * i + i] += 7;
 56:   i = 2;
 57:   j = 2;
 58:   PetscCall(MatSetValuesBlocked(A, 1, &i, 1, &j, values, INSERT_VALUES));

 60:   PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
 61:   PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
 62:   PetscCall(MatView(A, fd));
 63:   PetscCall(MatDestroy(&A));

 65:   PetscCall(VecCreateSeq(PETSC_COMM_WORLD, 12, &x));
 66:   PetscCall(VecSet(x, one));
 67:   PetscCall(VecView(x, fd));
 68:   PetscCall(VecDestroy(&x));

 70:   PetscCall(PetscViewerDestroy(&fd));
 71:   PetscCall(PetscFinalize());
 72:   return 0;
 73: }