xref: /petsc/src/dm/dt/tests/ex6.c (revision c4762a1b19cd2af06abeed90e8f9d34fb975dd94)
1*c4762a1bSJed Brown static char help[] = "Tests 1D Gauss-Lobatto-Legendre discretization on [-1, 1].\n\n";
2*c4762a1bSJed Brown 
3*c4762a1bSJed Brown #include <petscdt.h>
4*c4762a1bSJed Brown #include <petscviewer.h>
5*c4762a1bSJed Brown 
6*c4762a1bSJed Brown int main(int argc,char **argv)
7*c4762a1bSJed Brown {
8*c4762a1bSJed Brown   PetscErrorCode ierr;
9*c4762a1bSJed Brown 
10*c4762a1bSJed Brown   PetscInt       n = 3,i;
11*c4762a1bSJed Brown   PetscReal      *la_nodes,*la_weights,*n_nodes,*n_weights;
12*c4762a1bSJed Brown 
13*c4762a1bSJed Brown   ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
14*c4762a1bSJed Brown   ierr = PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);CHKERRQ(ierr);
15*c4762a1bSJed Brown 
16*c4762a1bSJed Brown   ierr = PetscMalloc1(n,&la_nodes);CHKERRQ(ierr);
17*c4762a1bSJed Brown   ierr = PetscMalloc1(n,&la_weights);CHKERRQ(ierr);
18*c4762a1bSJed Brown   ierr = PetscMalloc1(n,&n_nodes);CHKERRQ(ierr);
19*c4762a1bSJed Brown   ierr = PetscMalloc1(n,&n_weights);CHKERRQ(ierr);
20*c4762a1bSJed Brown   ierr = PetscDTGaussLobattoLegendreQuadrature(n,PETSCGAUSSLOBATTOLEGENDRE_VIA_LINEAR_ALGEBRA,la_nodes,la_weights);CHKERRQ(ierr);
21*c4762a1bSJed Brown 
22*c4762a1bSJed Brown   ierr = PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF,"Gauss-Lobatto-Legendre nodes and weights computed via linear algebra: \n");CHKERRQ(ierr);
23*c4762a1bSJed Brown   ierr = PetscRealView(n,la_nodes,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
24*c4762a1bSJed Brown   ierr = PetscRealView(n,la_weights,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
25*c4762a1bSJed Brown   ierr = PetscDTGaussLobattoLegendreQuadrature(n,PETSCGAUSSLOBATTOLEGENDRE_VIA_NEWTON,n_nodes,n_weights);CHKERRQ(ierr);
26*c4762a1bSJed Brown   ierr = PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF,"Gauss-Lobatto-Legendre nodes and weights computed via Newton: \n");CHKERRQ(ierr);
27*c4762a1bSJed Brown   ierr = PetscRealView(n,n_nodes,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
28*c4762a1bSJed Brown   ierr = PetscRealView(n,n_weights,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
29*c4762a1bSJed Brown 
30*c4762a1bSJed Brown   for (i=0; i<n; i++) {
31*c4762a1bSJed Brown     la_nodes[i]   -= n_nodes[i];
32*c4762a1bSJed Brown     la_weights[i] -= n_weights[i];
33*c4762a1bSJed Brown   }
34*c4762a1bSJed Brown   ierr = PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF,"Difference: \n");CHKERRQ(ierr);
35*c4762a1bSJed Brown   ierr = PetscRealView(n,la_nodes,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
36*c4762a1bSJed Brown   ierr = PetscRealView(n,la_weights,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
37*c4762a1bSJed Brown 
38*c4762a1bSJed Brown   ierr = PetscFree(la_nodes);CHKERRQ(ierr);
39*c4762a1bSJed Brown   ierr = PetscFree(la_weights);CHKERRQ(ierr);
40*c4762a1bSJed Brown   ierr = PetscFree(n_nodes);CHKERRQ(ierr);
41*c4762a1bSJed Brown   ierr = PetscFree(n_weights);CHKERRQ(ierr);
42*c4762a1bSJed Brown 
43*c4762a1bSJed Brown   ierr = PetscFinalize();
44*c4762a1bSJed Brown   return ierr;
45*c4762a1bSJed Brown }
46*c4762a1bSJed Brown 
47*c4762a1bSJed Brown /*TEST
48*c4762a1bSJed Brown 
49*c4762a1bSJed Brown    test:
50*c4762a1bSJed Brown 
51*c4762a1bSJed Brown TEST*/
52