1 static char help[] = "Tests reordering a matrix.\n\n"; 2 3 #include <petscmat.h> 4 5 int main(int argc, char **args) 6 { 7 Mat C; 8 PetscInt i, j, m = 5, n = 5, Ii, J; 9 PetscScalar v; 10 IS perm, iperm; 11 12 PetscFunctionBeginUser; 13 PetscCall(PetscInitialize(&argc, &args, (char *)0, help)); 14 PetscCall(MatCreate(PETSC_COMM_SELF, &C)); 15 PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n)); 16 PetscCall(MatSetFromOptions(C)); 17 PetscCall(MatSetUp(C)); 18 19 /* create the matrix for the five point stencil, YET AGAIN*/ 20 for (i = 0; i < m; i++) { 21 for (j = 0; j < n; j++) { 22 v = -1.0; 23 Ii = j + n * i; 24 if (i > 0) { 25 J = Ii - n; 26 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 27 } 28 if (i < m - 1) { 29 J = Ii + n; 30 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 31 } 32 if (j > 0) { 33 J = Ii - 1; 34 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 35 } 36 if (j < n - 1) { 37 J = Ii + 1; 38 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 39 } 40 v = 4.0; 41 PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES)); 42 } 43 } 44 PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY)); 45 PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY)); 46 47 PetscCall(MatGetOrdering(C, MATORDERINGND, &perm, &iperm)); 48 PetscCall(ISView(perm, PETSC_VIEWER_STDOUT_SELF)); 49 PetscCall(ISView(iperm, PETSC_VIEWER_STDOUT_SELF)); 50 PetscCall(MatView(C, PETSC_VIEWER_STDOUT_SELF)); 51 52 PetscCall(ISDestroy(&perm)); 53 PetscCall(ISDestroy(&iperm)); 54 PetscCall(MatDestroy(&C)); 55 PetscCall(PetscFinalize()); 56 return 0; 57 } 58 59 /*TEST 60 61 test: 62 63 TEST*/ 64