1 2 static char help[] = "Tests sequential and parallel MatGetRow() and MatRestoreRow().\n"; 3 4 #include <petscmat.h> 5 6 int main(int argc, char **args) 7 { 8 Mat C; 9 PetscInt i, j, m = 5, n = 5, Ii, J, nz, rstart, rend; 10 PetscMPIInt rank; 11 const PetscInt *idx; 12 PetscScalar v; 13 const PetscScalar *values; 14 15 PetscFunctionBeginUser; 16 PetscCall(PetscInitialize(&argc, &args, (char *)0, help)); 17 /* Create the matrix for the five point stencil, YET AGAIN */ 18 PetscCall(MatCreate(PETSC_COMM_WORLD, &C)); 19 PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n)); 20 PetscCall(MatSetFromOptions(C)); 21 PetscCall(MatSetUp(C)); 22 for (i = 0; i < m; i++) { 23 for (j = 0; j < n; j++) { 24 v = -1.0; 25 Ii = j + n * i; 26 if (i > 0) { 27 J = Ii - n; 28 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 29 } 30 if (i < m - 1) { 31 J = Ii + n; 32 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 33 } 34 if (j > 0) { 35 J = Ii - 1; 36 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 37 } 38 if (j < n - 1) { 39 J = Ii + 1; 40 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 41 } 42 v = 4.0; 43 PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES)); 44 } 45 } 46 PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY)); 47 PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY)); 48 PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD)); 49 50 PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank)); 51 PetscCall(MatGetOwnershipRange(C, &rstart, &rend)); 52 for (i = rstart; i < rend; i++) { 53 PetscCall(MatGetRow(C, i, &nz, &idx, &values)); 54 if (rank == 0) { 55 for (j = 0; j < nz; j++) PetscCall(PetscPrintf(PETSC_COMM_SELF, "%" PetscInt_FMT " %g ", idx[j], (double)PetscRealPart(values[j]))); 56 PetscCall(PetscPrintf(PETSC_COMM_SELF, "\n")); 57 } 58 PetscCall(MatRestoreRow(C, i, &nz, &idx, &values)); 59 } 60 61 PetscCall(MatDestroy(&C)); 62 PetscCall(PetscFinalize()); 63 return 0; 64 } 65 66 /*TEST 67 68 test: 69 70 TEST*/ 71