Actual source code: ex1.c
1: static char help[] = "Define a simple field over the mesh\n\n";
3: #include <petscdmplex.h>
5: int main(int argc, char **argv)
6: {
7: DM dm;
8: Vec u;
9: PetscSection section;
10: PetscViewer viewer;
11: PetscInt dim, numFields, numBC, i;
12: PetscInt numComp[3];
13: PetscInt numDof[12];
14: PetscInt bcField[1];
15: IS bcPointIS[1];
17: PetscInitialize(&argc, &argv, NULL,help);
18: /* Create a mesh */
19: DMCreate(PETSC_COMM_WORLD, &dm);
20: DMSetType(dm, DMPLEX);
21: DMSetFromOptions(dm);
22: DMViewFromOptions(dm, NULL, "-dm_view");
23: DMGetDimension(dm, &dim);
24: /* Create a scalar field u, a vector field v, and a surface vector field w */
25: numFields = 3;
26: numComp[0] = 1;
27: numComp[1] = dim;
28: numComp[2] = dim-1;
29: for (i = 0; i < numFields*(dim+1); ++i) numDof[i] = 0;
30: /* Let u be defined on vertices */
31: numDof[0*(dim+1)+0] = 1;
32: /* Let v be defined on cells */
33: numDof[1*(dim+1)+dim] = dim;
34: /* Let w be defined on faces */
35: numDof[2*(dim+1)+dim-1] = dim-1;
36: /* Setup boundary conditions */
37: numBC = 1;
38: /* Prescribe a Dirichlet condition on u on the boundary
39: Label "marker" is made by the mesh creation routine */
40: bcField[0] = 0;
41: DMGetStratumIS(dm, "marker", 1, &bcPointIS[0]);
42: /* Create a PetscSection with this data layout */
43: DMSetNumFields(dm, numFields);
44: DMPlexCreateSection(dm, NULL, numComp, numDof, numBC, bcField, NULL, bcPointIS, NULL, §ion);
45: ISDestroy(&bcPointIS[0]);
46: /* Name the Field variables */
47: PetscSectionSetFieldName(section, 0, "u");
48: PetscSectionSetFieldName(section, 1, "v");
49: PetscSectionSetFieldName(section, 2, "w");
50: PetscSectionView(section, PETSC_VIEWER_STDOUT_WORLD);
51: /* Tell the DM to use this data layout */
52: DMSetLocalSection(dm, section);
53: /* Create a Vec with this layout and view it */
54: DMGetGlobalVector(dm, &u);
55: PetscViewerCreate(PETSC_COMM_WORLD, &viewer);
56: PetscViewerSetType(viewer, PETSCVIEWERVTK);
57: PetscViewerFileSetName(viewer, "sol.vtu");
58: VecView(u, viewer);
59: PetscViewerDestroy(&viewer);
60: DMRestoreGlobalVector(dm, &u);
61: /* Cleanup */
62: PetscSectionDestroy(§ion);
63: DMDestroy(&dm);
64: PetscFinalize();
65: return 0;
66: }
68: /*TEST
70: test:
71: suffix: 0
72: requires: triangle
73: args: -info :~sys,mat
74: test:
75: suffix: 1
76: requires: ctetgen
77: args: -dm_plex_dim 3 -info :~sys,mat
79: TEST*/