Actual source code: ex64.c


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

  4: #include <petscmat.h>

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

 15:   PetscFunctionBeginUser;
 16:   PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
 17:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
 18:   PetscCheck(size == 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, m "Can only run on one processor");

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

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

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

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

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

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

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

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

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

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

 71:   PetscCall(PetscViewerDestroy(&fd));
 72:   PetscCall(PetscFinalize());
 73:   return 0;
 74: }