1 2 static char help[] = "Tests reordering a matrix.\n\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; 10 PetscScalar v; 11 IS perm, iperm; 12 13 PetscFunctionBeginUser; 14 PetscCall(PetscInitialize(&argc, &args, (char *)0, help)); 15 PetscCall(MatCreate(PETSC_COMM_SELF, &C)); 16 PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n)); 17 PetscCall(MatSetFromOptions(C)); 18 PetscCall(MatSetUp(C)); 19 20 /* create the matrix for the five point stencil, YET AGAIN*/ 21 for (i = 0; i < m; i++) { 22 for (j = 0; j < n; j++) { 23 v = -1.0; 24 Ii = j + n * i; 25 if (i > 0) { 26 J = Ii - n; 27 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 28 } 29 if (i < m - 1) { 30 J = Ii + n; 31 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 32 } 33 if (j > 0) { 34 J = Ii - 1; 35 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 36 } 37 if (j < n - 1) { 38 J = Ii + 1; 39 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES)); 40 } 41 v = 4.0; 42 PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES)); 43 } 44 } 45 PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY)); 46 PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY)); 47 48 PetscCall(MatGetOrdering(C, MATORDERINGND, &perm, &iperm)); 49 PetscCall(ISView(perm, PETSC_VIEWER_STDOUT_SELF)); 50 PetscCall(ISView(iperm, PETSC_VIEWER_STDOUT_SELF)); 51 PetscCall(MatView(C, PETSC_VIEWER_STDOUT_SELF)); 52 53 PetscCall(ISDestroy(&perm)); 54 PetscCall(ISDestroy(&iperm)); 55 PetscCall(MatDestroy(&C)); 56 PetscCall(PetscFinalize()); 57 return 0; 58 } 59 60 /*TEST 61 62 test: 63 64 TEST*/ 65