Actual source code: ex6.c
1: static char help[] = "Tests 1D Gauss-Lobatto-Legendre discretization on [-1, 1].\n\n";
3: #include <petscdt.h>
4: #include <petscviewer.h>
6: int main(int argc, char **argv)
7: {
8: PetscInt n = 3, i;
9: PetscReal *la_nodes, *la_weights, *n_nodes, *n_weights;
12: PetscInitialize(&argc, &argv, (char *)0, help);
13: PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL);
15: PetscMalloc1(n, &la_nodes);
16: PetscMalloc1(n, &la_weights);
17: PetscMalloc1(n, &n_nodes);
18: PetscMalloc1(n, &n_weights);
19: PetscDTGaussLobattoLegendreQuadrature(n, PETSCGAUSSLOBATTOLEGENDRE_VIA_LINEAR_ALGEBRA, la_nodes, la_weights);
21: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF, "Gauss-Lobatto-Legendre nodes and weights computed via linear algebra: \n");
22: PetscRealView(n, la_nodes, PETSC_VIEWER_STDOUT_SELF);
23: PetscRealView(n, la_weights, PETSC_VIEWER_STDOUT_SELF);
24: PetscDTGaussLobattoLegendreQuadrature(n, PETSCGAUSSLOBATTOLEGENDRE_VIA_NEWTON, n_nodes, n_weights);
25: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF, "Gauss-Lobatto-Legendre nodes and weights computed via Newton: \n");
26: PetscRealView(n, n_nodes, PETSC_VIEWER_STDOUT_SELF);
27: PetscRealView(n, n_weights, PETSC_VIEWER_STDOUT_SELF);
29: for (i = 0; i < n; i++) {
30: la_nodes[i] -= n_nodes[i];
31: la_weights[i] -= n_weights[i];
32: }
33: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF, "Difference: \n");
34: PetscRealView(n, la_nodes, PETSC_VIEWER_STDOUT_SELF);
35: PetscRealView(n, la_weights, PETSC_VIEWER_STDOUT_SELF);
37: PetscFree(la_nodes);
38: PetscFree(la_weights);
39: PetscFree(n_nodes);
40: PetscFree(n_weights);
42: PetscFinalize();
43: return 0;
44: }
46: /*TEST
48: test:
50: TEST*/