PETSC_STATIC_INLINE PetscErrorCode DMPlexGetGlobalFieldOffset_Private(DM dm,PetscInt point,PetscInt field,PetscInt *offset)
{
PetscFunctionBegin;
#if defined(PETSC_USE_DEBUG)
{
PetscErrorCode ierr;
PetscInt loff,lfoff,dof,cdof;
ierr = PetscSectionGetOffset(dm->defaultGlobalSection,point,offset);CHKERRQ(ierr);
ierr = PetscSectionGetOffset(dm->defaultSection,point,&loff);CHKERRQ(ierr);
ierr = PetscSectionGetFieldOffset(dm->defaultSection,point,field,&lfoff);CHKERRQ(ierr);
ierr = PetscSectionGetFieldDof(dm->defaultSection,point,field,&dof);CHKERRQ(ierr);
ierr = PetscSectionGetFieldConstraintDof(dm->defaultSection,point,field,&cdof);CHKERRQ(ierr);
*offset += lfoff - loff;
if (dof-cdof <= 0) *offset = -1; /* Indicates no data */
}
#else
{
PetscSection s = dm->defaultSection;
PetscSection fs = dm->defaultSection->field[field];
PetscSection gs = dm->defaultGlobalSection;
PetscInt dof,cdof,loff,lfoff;
loff = s->atlasOff[point - s->pStart];
lfoff = fs->atlasOff[point - s->pStart];
dof = s->atlasDof[point - s->pStart];
cdof = s->bc ? s->bc->atlasDof[point - s->bc->pStart] : 0;
*offset = gs->atlasOff[point - s->pStart] + lfoff - loff;
if (dof-cdof <= 0) *offset = -1;
}
#endif
PetscFunctionReturn(0);
}
PetscErrorCode CreatePressureNullSpace(DM dm, AppCtx *user, MatNullSpace *nullSpace)
{
Vec vec, localVec;
PetscErrorCode ierr;
PetscFunctionBeginUser;
ierr = DMGetGlobalVector(dm, &vec);CHKERRQ(ierr);
ierr = DMGetLocalVector(dm, &localVec);CHKERRQ(ierr);
ierr = VecSet(vec, 0.0);CHKERRQ(ierr);
/* Put a constant in for all pressures
Could change this to project the constant function onto the pressure space (when that is finished) */
{
PetscSection section;
PetscInt pStart, pEnd, p;
PetscScalar *a;
ierr = DMGetDefaultSection(dm, §ion);CHKERRQ(ierr);
ierr = PetscSectionGetChart(section, &pStart, &pEnd);CHKERRQ(ierr);
ierr = VecGetArray(localVec, &a);CHKERRQ(ierr);
for (p = pStart; p < pEnd; ++p) {
PetscInt fDim, off, d;
ierr = PetscSectionGetFieldDof(section, p, 1, &fDim);CHKERRQ(ierr);
ierr = PetscSectionGetFieldOffset(section, p, 1, &off);CHKERRQ(ierr);
for (d = 0; d < fDim; ++d) a[off+d] = 1.0;
}
ierr = VecRestoreArray(localVec, &a);CHKERRQ(ierr);
}
ierr = DMLocalToGlobalBegin(dm, localVec, INSERT_VALUES, vec);CHKERRQ(ierr);
ierr = DMLocalToGlobalEnd(dm, localVec, INSERT_VALUES, vec);CHKERRQ(ierr);
ierr = DMRestoreLocalVector(dm, &localVec);CHKERRQ(ierr);
ierr = VecNormalize(vec, NULL);CHKERRQ(ierr);
if (user->debug) {
ierr = PetscPrintf(PetscObjectComm((PetscObject)dm), "Pressure Null Space\n");CHKERRQ(ierr);
ierr = VecView(vec, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
}
ierr = MatNullSpaceCreate(PetscObjectComm((PetscObject)dm), PETSC_FALSE, 1, &vec, nullSpace);CHKERRQ(ierr);
ierr = DMRestoreGlobalVector(dm, &vec);CHKERRQ(ierr);
/* New style for field null spaces */
{
PetscObject pressure;
MatNullSpace nullSpacePres;
ierr = DMGetField(dm, 1, &pressure);CHKERRQ(ierr);
ierr = MatNullSpaceCreate(PetscObjectComm(pressure), PETSC_TRUE, 0, NULL, &nullSpacePres);CHKERRQ(ierr);
ierr = PetscObjectCompose(pressure, "nullspace", (PetscObject) nullSpacePres);CHKERRQ(ierr);
ierr = MatNullSpaceDestroy(&nullSpacePres);CHKERRQ(ierr);
}
PetscFunctionReturn(0);
}
PETSC_STATIC_INLINE PetscErrorCode DMPlexGetLocalFieldOffset_Private(DM dm,PetscInt point,PetscInt field,PetscInt *offset)
{
PetscFunctionBegin;
#if defined(PETSC_USE_DEBUG)
{
PetscErrorCode ierr;
ierr = PetscSectionGetFieldOffset(dm->defaultSection,point,field,offset);CHKERRQ(ierr);
}
#else
{
PetscSection s = dm->defaultSection->field[field];
*offset = s->atlasOff[point - s->pStart];
}
#endif
PetscFunctionReturn(0);
}
void test(DM mesh) {
const int dim = 2;
const int field_count = 1;
int components[field_count];
int dof[field_count*(dim+1)];
// Field 0 - temperature
components[0] = 1;
dof[0*(dim+1) + 0] = 1; // vertices
dof[0*(dim+1) + 1] = 0; // faces
// Field 1 - pressure
components[1] = 1;
dof[1*(dim+1) + 0] = 64; // vertices
dof[1*(dim+1) + 1] = 0; // faces
PetscSection section;
DMPlexCreateSection(mesh,
dim, // Spatial dimension
field_count, // Number of fields
components, // Component count for each field
dof, // DoF for each field component
0, // Number of boundary conditions
NULL, // BC Field
NULL, // BC Points
§ion);
DMSetDefaultSection(mesh, section);
// Temperature
// Create a global vector
Vec temperature = NULL;
DMCreateGlobalVector(mesh, &temperature);
// Get a temporary local vector & a pointer to its data
Vec localTemp = NULL;
DMGetLocalVector(mesh, &localTemp);
PetscScalar * data = NULL;
VecGetArray(localTemp, &data);
// Loop over points in the section
int start, end;
DMGetDefaultSection(mesh, §ion);
PetscSectionGetChart(section, &start, &end);
for (int point=start; point<end; ++point) {
// Get the size & offset of field 0
int dof, offset;
PetscSectionGetFieldDof(section, point, 0, &dof);
PetscSectionGetFieldOffset(section, point, 0, &offset);
// Set values
for (int d=0; d<dof; ++d){
data[offset+d] = point * 100 + d;
}
}
VecRestoreArray(localTemp, &data);
// Broadcast values
DMLocalToGlobalBegin(mesh, localTemp, INSERT_VALUES, temperature);
DMLocalToGlobalEnd(mesh, localTemp, INSERT_VALUES, temperature);
// Now each node should have all temperature values
// Free the temp vector
DMRestoreLocalVector(mesh,&localTemp);
}
