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 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