xref: /petsc/src/dm/dt/tests/ex2.c (revision ccb4e88a40f0b86eaeca07ff64c64e4de2fae686)
1 static char help[] = "Tests 1D cell-based discretization tools.\n\n";
2 
3 #include <petscdt.h>
4 #include <petscviewer.h>
5 
6 int main(int argc,char **argv)
7 {
8   PetscErrorCode ierr;
9   PetscInt       i,j,degrees[1000],ndegrees,nsrc_points,ntarget_points;
10   PetscReal      src_points[1000],target_points[1000],*R;
11   PetscBool      flg;
12 
13   ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
14   ierr = PetscOptionsBegin(PETSC_COMM_WORLD,NULL,"Discretization tools test options",NULL);CHKERRQ(ierr);
15   {
16     ndegrees   = 1000;
17     degrees[0] = 1;
18     degrees[1] = 2;
19     degrees[2] = 3;
20     ierr = PetscOptionsIntArray("-degrees","list of max degrees to evaluate","",degrees,&ndegrees,&flg);CHKERRQ(ierr);
21     if (!flg) ndegrees = 3;
22 
23     nsrc_points   = 1000;
24     src_points[0] = -1.;
25     src_points[1] = 0.;
26     src_points[2] = 1.;
27     ierr = PetscOptionsRealArray("-src_points","list of points defining intervals on which to integrate","",src_points,&nsrc_points,&flg);CHKERRQ(ierr);
28     if (!flg) nsrc_points = 3;
29 
30     ntarget_points   = 1000;
31     target_points[0] = -1.;
32     target_points[1] = 0.;
33     target_points[2] = 1.;
34     ierr = PetscOptionsRealArray("-target_points","list of points defining intervals on which to integrate","",target_points,&ntarget_points,&flg);CHKERRQ(ierr);
35     if (!flg) ntarget_points = 3;
36   }
37   ierr = PetscOptionsEnd();CHKERRQ(ierr);
38 
39   ierr = PetscMalloc1((nsrc_points-1)*(ntarget_points-1),&R);CHKERRQ(ierr);
40   for (i=0; i<ndegrees; i++) {
41     ierr = PetscDTReconstructPoly(degrees[i],nsrc_points-1,src_points,ntarget_points-1,target_points,R);CHKERRQ(ierr);
42     for (j=0; j<(ntarget_points-1)*(nsrc_points-1); j++) { /* Truncate to zero for nicer output */
43       if (PetscAbs(R[j]) < 10*PETSC_MACHINE_EPSILON) R[j] = 0;
44     }
45     for (j=0; j<ntarget_points-1; j++) {
46       ierr = PetscPrintf(PETSC_COMM_WORLD,"Degree %D target interval (%g,%g)\n",degrees[i],(double)target_points[j],(double)target_points[j+1]);CHKERRQ(ierr);
47       ierr = PetscRealView(nsrc_points-1,R+j*(nsrc_points-1),PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
48     }
49   }
50   ierr = PetscFree(R);CHKERRQ(ierr);
51   ierr = PetscFinalize();
52   return ierr;
53 }
54 
55 /*TEST
56   test:
57     suffix: 1
58     args: -degrees 1,2,3 -target_points -0.3,0,.2 -src_points -1,-.3,0,.2,1
59 TEST*/
60