/*
There is a problem here with uninterpolated meshes. The index in numDof[] is not dimension in this case,
but sieve depth.
*/
PetscErrorCode SetupSection(DM dm, AppCtx *user)
{
PetscSection section;
const PetscInt numFields = NUM_FIELDS;
PetscInt dim = user->dim;
PetscInt numBC = 0;
PetscInt bcFields[1] = {0};
IS bcPoints[1] = {NULL};
PetscInt numComp[NUM_FIELDS];
const PetscInt *numFieldDof[NUM_FIELDS];
PetscInt *numDof;
PetscInt f, d;
PetscErrorCode ierr;
PetscFunctionBeginUser;
ierr = PetscFEGetNumComponents(user->fe[0], &numComp[0]);CHKERRQ(ierr);
ierr = PetscFEGetNumComponents(user->fe[1], &numComp[1]);CHKERRQ(ierr);
ierr = PetscFEGetNumDof(user->fe[0], &numFieldDof[0]);CHKERRQ(ierr);
ierr = PetscFEGetNumDof(user->fe[1], &numFieldDof[1]);CHKERRQ(ierr);
ierr = PetscMalloc(NUM_FIELDS*(dim+1) * sizeof(PetscInt), &numDof);CHKERRQ(ierr);
for (f = 0; f < NUM_FIELDS; ++f) {
for (d = 0; d <= dim; ++d) {
numDof[f*(dim+1)+d] = numFieldDof[f][d];
}
}
for (f = 0; f < numFields; ++f) {
for (d = 1; d < dim; ++d) {
if ((numDof[f*(dim+1)+d] > 0) && !user->interpolate) SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Mesh must be interpolated when unknowns are specified on edges or faces.");
}
}
if (user->bcType == DIRICHLET) {
numBC = 1;
ierr = DMPlexGetStratumIS(dm, "marker", 1, &bcPoints[0]);CHKERRQ(ierr);
}
ierr = DMPlexCreateSection(dm, dim, numFields, numComp, numDof, numBC, bcFields, bcPoints, §ion);CHKERRQ(ierr);
ierr = PetscSectionSetFieldName(section, 0, "velocity");CHKERRQ(ierr);
ierr = PetscSectionSetFieldName(section, 1, "pressure");CHKERRQ(ierr);
ierr = DMSetDefaultSection(dm, section);CHKERRQ(ierr);
ierr = PetscSectionDestroy(§ion);CHKERRQ(ierr);
if (user->bcType == DIRICHLET) {
ierr = ISDestroy(&bcPoints[0]);CHKERRQ(ierr);
}
ierr = PetscFree(numDof);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
/*
There is a problem here with uninterpolated meshes. The index in numDof[] is not dimension in this case,
but sieve depth.
*/
PetscErrorCode SetupSection(DM dm, AppCtx *user)
{
PetscSection section;
const PetscInt numFields = NUM_FIELDS;
PetscInt dim = user->dim;
PetscInt numBC = 0;
PetscInt numComp[NUM_FIELDS] = {NUM_BASIS_COMPONENTS_0, NUM_BASIS_COMPONENTS_1};
PetscInt bcFields[1] = {0};
IS bcPoints[1] = {NULL};
PetscInt numDof[NUM_FIELDS*(SPATIAL_DIM_0+1)];
PetscInt f, d;
PetscErrorCode ierr;
PetscFunctionBeginUser;
if (dim != SPATIAL_DIM_0) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_SIZ, "Spatial dimension %d should be %d", dim, SPATIAL_DIM_0);
if (dim != SPATIAL_DIM_1) SETERRQ2(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_SIZ, "Spatial dimension %d should be %d", dim, SPATIAL_DIM_1);
for (d = 0; d <= dim; ++d) {
numDof[0*(dim+1)+d] = numDof_0[d];
numDof[1*(dim+1)+d] = numDof_1[d];
}
for (f = 0; f < numFields; ++f) {
for (d = 1; d < dim; ++d) {
if ((numDof[f*(dim+1)+d] > 0) && !user->interpolate) SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONG, "Mesh must be interpolated when unknowns are specified on edges or faces.");
}
}
if (user->bcType == DIRICHLET) {
numBC = 1;
ierr = DMPlexGetStratumIS(dm, "marker", 1, &bcPoints[0]);CHKERRQ(ierr);
}
ierr = DMPlexCreateSection(dm, dim, numFields, numComp, numDof, numBC, bcFields, bcPoints, §ion);CHKERRQ(ierr);
ierr = PetscSectionSetFieldName(section, 0, "velocity");CHKERRQ(ierr);
ierr = PetscSectionSetFieldName(section, 1, "pressure");CHKERRQ(ierr);
ierr = DMSetDefaultSection(dm, section);CHKERRQ(ierr);
if (user->bcType == DIRICHLET) {
ierr = ISDestroy(&bcPoints[0]);CHKERRQ(ierr);
}
PetscFunctionReturn(0);
}
int main(int argc, char **argv)
{
DM dm, dmDist = NULL;
Vec u;
PetscSection section;
PetscViewer viewer;
PetscInt dim = 2, numFields, numBC, i;
PetscInt numComp[3];
PetscInt numDof[12];
PetscInt bcField[1];
IS bcPointIS[1];
PetscBool interpolate = PETSC_TRUE;
PetscErrorCode ierr;
ierr = PetscInitialize(&argc, &argv, NULL,help);if (ierr) return ierr;
ierr = PetscOptionsGetInt(NULL,NULL, "-dim", &dim, NULL);CHKERRQ(ierr);
/* Create a mesh */
ierr = DMPlexCreateBoxMesh(PETSC_COMM_WORLD, dim, PETSC_TRUE, NULL, NULL, NULL, NULL, interpolate, &dm);CHKERRQ(ierr);
/* Distribute mesh over processes */
ierr = DMPlexDistribute(dm, 0, NULL, &dmDist);CHKERRQ(ierr);
if (dmDist) {ierr = DMDestroy(&dm);CHKERRQ(ierr); dm = dmDist;}
/* Create a scalar field u, a vector field v, and a surface vector field w */
numFields = 3;
numComp[0] = 1;
numComp[1] = dim;
numComp[2] = dim-1;
for (i = 0; i < numFields*(dim+1); ++i) numDof[i] = 0;
/* Let u be defined on vertices */
numDof[0*(dim+1)+0] = 1;
/* Let v be defined on cells */
numDof[1*(dim+1)+dim] = dim;
/* Let v be defined on faces */
numDof[2*(dim+1)+dim-1] = dim-1;
/* Setup boundary conditions */
numBC = 1;
/* Prescribe a Dirichlet condition on u on the boundary
Label "marker" is made by the mesh creation routine */
bcField[0] = 0;
ierr = DMGetStratumIS(dm, "marker", 1, &bcPointIS[0]);CHKERRQ(ierr);
/* Create a PetscSection with this data layout */
ierr = DMSetNumFields(dm, numFields);CHKERRQ(ierr);
ierr = DMPlexCreateSection(dm, NULL, numComp, numDof, numBC, bcField, NULL, bcPointIS, NULL, §ion);CHKERRQ(ierr);
ierr = ISDestroy(&bcPointIS[0]);CHKERRQ(ierr);
/* Name the Field variables */
ierr = PetscSectionSetFieldName(section, 0, "u");CHKERRQ(ierr);
ierr = PetscSectionSetFieldName(section, 1, "v");CHKERRQ(ierr);
ierr = PetscSectionSetFieldName(section, 2, "w");CHKERRQ(ierr);
ierr = PetscSectionView(section, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
/* Tell the DM to use this data layout */
ierr = DMSetSection(dm, section);CHKERRQ(ierr);
/* Create a Vec with this layout and view it */
ierr = DMGetGlobalVector(dm, &u);CHKERRQ(ierr);
ierr = PetscViewerCreate(PETSC_COMM_WORLD, &viewer);CHKERRQ(ierr);
ierr = PetscViewerSetType(viewer, PETSCVIEWERVTK);CHKERRQ(ierr);
ierr = PetscViewerPushFormat(viewer, PETSC_VIEWER_ASCII_VTK);CHKERRQ(ierr);
ierr = PetscViewerFileSetName(viewer, "sol.vtk");CHKERRQ(ierr);
ierr = VecView(u, viewer);CHKERRQ(ierr);
ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
ierr = DMRestoreGlobalVector(dm, &u);CHKERRQ(ierr);
/* Cleanup */
ierr = PetscSectionDestroy(§ion);CHKERRQ(ierr);
ierr = DMDestroy(&dm);CHKERRQ(ierr);
ierr = PetscFinalize();
return ierr;
}
