1 static char help[] = "Tests 1D Gauss-Lobatto-Legendre discretization on [-1, 1].\n\n";
2
3 #include <petscdt.h>
4 #include <petscviewer.h>
5
main(int argc,char ** argv)6 int main(int argc, char **argv)
7 {
8 PetscInt n = 3, i;
9 PetscReal *la_nodes, *la_weights, *n_nodes, *n_weights;
10
11 PetscFunctionBeginUser;
12 PetscCall(PetscInitialize(&argc, &argv, NULL, help));
13 PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL));
14
15 PetscCall(PetscMalloc1(n, &la_nodes));
16 PetscCall(PetscMalloc1(n, &la_weights));
17 PetscCall(PetscMalloc1(n, &n_nodes));
18 PetscCall(PetscMalloc1(n, &n_weights));
19 PetscCall(PetscDTGaussLobattoLegendreQuadrature(n, PETSCGAUSSLOBATTOLEGENDRE_VIA_LINEAR_ALGEBRA, la_nodes, la_weights));
20
21 PetscCall(PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF, "Gauss-Lobatto-Legendre nodes and weights computed via linear algebra: \n"));
22 PetscCall(PetscRealView(n, la_nodes, PETSC_VIEWER_STDOUT_SELF));
23 PetscCall(PetscRealView(n, la_weights, PETSC_VIEWER_STDOUT_SELF));
24 PetscCall(PetscDTGaussLobattoLegendreQuadrature(n, PETSCGAUSSLOBATTOLEGENDRE_VIA_NEWTON, n_nodes, n_weights));
25 PetscCall(PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF, "Gauss-Lobatto-Legendre nodes and weights computed via Newton: \n"));
26 PetscCall(PetscRealView(n, n_nodes, PETSC_VIEWER_STDOUT_SELF));
27 PetscCall(PetscRealView(n, n_weights, PETSC_VIEWER_STDOUT_SELF));
28
29 for (i = 0; i < n; i++) {
30 la_nodes[i] -= n_nodes[i];
31 la_weights[i] -= n_weights[i];
32 }
33 PetscCall(PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF, "Difference: \n"));
34 PetscCall(PetscRealView(n, la_nodes, PETSC_VIEWER_STDOUT_SELF));
35 PetscCall(PetscRealView(n, la_weights, PETSC_VIEWER_STDOUT_SELF));
36
37 PetscCall(PetscFree(la_nodes));
38 PetscCall(PetscFree(la_weights));
39 PetscCall(PetscFree(n_nodes));
40 PetscCall(PetscFree(n_weights));
41
42 PetscCall(PetscFinalize());
43 return 0;
44 }
45
46 /*TEST
47
48 test:
49
50 TEST*/
51