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