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 PetscErrorCode ierr; 9 10 PetscInt n = 3,i; 11 PetscReal *la_nodes,*la_weights,*n_nodes,*n_weights; 12 13 ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr; 14 ierr = PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);CHKERRQ(ierr); 15 16 ierr = PetscMalloc1(n,&la_nodes);CHKERRQ(ierr); 17 ierr = PetscMalloc1(n,&la_weights);CHKERRQ(ierr); 18 ierr = PetscMalloc1(n,&n_nodes);CHKERRQ(ierr); 19 ierr = PetscMalloc1(n,&n_weights);CHKERRQ(ierr); 20 ierr = PetscDTGaussLobattoLegendreQuadrature(n,PETSCGAUSSLOBATTOLEGENDRE_VIA_LINEAR_ALGEBRA,la_nodes,la_weights);CHKERRQ(ierr); 21 22 ierr = PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF,"Gauss-Lobatto-Legendre nodes and weights computed via linear algebra: \n");CHKERRQ(ierr); 23 ierr = PetscRealView(n,la_nodes,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr); 24 ierr = PetscRealView(n,la_weights,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr); 25 ierr = PetscDTGaussLobattoLegendreQuadrature(n,PETSCGAUSSLOBATTOLEGENDRE_VIA_NEWTON,n_nodes,n_weights);CHKERRQ(ierr); 26 ierr = PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF,"Gauss-Lobatto-Legendre nodes and weights computed via Newton: \n");CHKERRQ(ierr); 27 ierr = PetscRealView(n,n_nodes,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr); 28 ierr = PetscRealView(n,n_weights,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr); 29 30 for (i=0; i<n; i++) { 31 la_nodes[i] -= n_nodes[i]; 32 la_weights[i] -= n_weights[i]; 33 } 34 ierr = PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF,"Difference: \n");CHKERRQ(ierr); 35 ierr = PetscRealView(n,la_nodes,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr); 36 ierr = PetscRealView(n,la_weights,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr); 37 38 ierr = PetscFree(la_nodes);CHKERRQ(ierr); 39 ierr = PetscFree(la_weights);CHKERRQ(ierr); 40 ierr = PetscFree(n_nodes);CHKERRQ(ierr); 41 ierr = PetscFree(n_weights);CHKERRQ(ierr); 42 43 ierr = PetscFinalize(); 44 return ierr; 45 } 46 47 /*TEST 48 49 test: 50 51 TEST*/ 52