C++ (Cpp) PetscSectionGetFieldComponents Examples

Example #1

File: plexinterpolate.c Project: tom-klotz/petsc

/*@
  DMPlexCopyCoordinates - Copy coordinates from one mesh to another with the same vertices

  Collective on DM

  Input Parameter:
. dmA - The DMPlex object with initial coordinates

  Output Parameter:
. dmB - The DMPlex object with copied coordinates

  Level: intermediate

  Note: This is typically used when adding pieces other than vertices to a mesh

.keywords: mesh
.seealso: DMCopyLabels(), DMGetCoordinates(), DMGetCoordinatesLocal(), DMGetCoordinateDM(), DMGetCoordinateSection()
@*/
PetscErrorCode DMPlexCopyCoordinates(DM dmA, DM dmB)
{
  Vec            coordinatesA, coordinatesB;
  PetscSection   coordSectionA, coordSectionB;
  PetscScalar   *coordsA, *coordsB;
  PetscInt       spaceDim, vStartA, vStartB, vEndA, vEndB, coordSizeB, v, d;
  PetscErrorCode ierr;

  PetscFunctionBegin;
  if (dmA == dmB) PetscFunctionReturn(0);
  ierr = DMPlexGetDepthStratum(dmA, 0, &vStartA, &vEndA);CHKERRQ(ierr);
  ierr = DMPlexGetDepthStratum(dmB, 0, &vStartB, &vEndB);CHKERRQ(ierr);
  if ((vEndA-vStartA) != (vEndB-vStartB)) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "The number of vertices in first DM %d != %d in the second DM", vEndA-vStartA, vEndB-vStartB);
  ierr = DMGetCoordinateSection(dmA, &coordSectionA);CHKERRQ(ierr);
  ierr = DMGetCoordinateSection(dmB, &coordSectionB);CHKERRQ(ierr);
  if (!coordSectionB) {
    PetscInt dim;

    ierr = PetscSectionCreate(PetscObjectComm((PetscObject) coordSectionA), &coordSectionB);CHKERRQ(ierr);
    ierr = DMGetCoordinateDim(dmA, &dim);CHKERRQ(ierr);
    ierr = DMSetCoordinateSection(dmB, dim, coordSectionB);CHKERRQ(ierr);
    ierr = PetscObjectDereference((PetscObject) coordSectionB);CHKERRQ(ierr);
  }
  ierr = PetscSectionSetNumFields(coordSectionB, 1);CHKERRQ(ierr);
  ierr = PetscSectionGetFieldComponents(coordSectionA, 0, &spaceDim);CHKERRQ(ierr);
  ierr = PetscSectionSetFieldComponents(coordSectionB, 0, spaceDim);CHKERRQ(ierr);
  ierr = PetscSectionSetChart(coordSectionB, vStartB, vEndB);CHKERRQ(ierr);
  for (v = vStartB; v < vEndB; ++v) {
    ierr = PetscSectionSetDof(coordSectionB, v, spaceDim);CHKERRQ(ierr);
    ierr = PetscSectionSetFieldDof(coordSectionB, v, 0, spaceDim);CHKERRQ(ierr);
  }
  ierr = PetscSectionSetUp(coordSectionB);CHKERRQ(ierr);
  ierr = PetscSectionGetStorageSize(coordSectionB, &coordSizeB);CHKERRQ(ierr);
  ierr = DMGetCoordinatesLocal(dmA, &coordinatesA);CHKERRQ(ierr);
  ierr = VecCreate(PetscObjectComm((PetscObject) dmB), &coordinatesB);CHKERRQ(ierr);
  ierr = PetscObjectSetName((PetscObject) coordinatesB, "coordinates");CHKERRQ(ierr);
  ierr = VecSetSizes(coordinatesB, coordSizeB, PETSC_DETERMINE);CHKERRQ(ierr);
  ierr = VecSetType(coordinatesB,VECSTANDARD);CHKERRQ(ierr);
  ierr = VecGetArray(coordinatesA, &coordsA);CHKERRQ(ierr);
  ierr = VecGetArray(coordinatesB, &coordsB);CHKERRQ(ierr);
  for (v = 0; v < vEndB-vStartB; ++v) {
    for (d = 0; d < spaceDim; ++d) {
      coordsB[v*spaceDim+d] = coordsA[v*spaceDim+d];
    }
  }
  ierr = VecRestoreArray(coordinatesA, &coordsA);CHKERRQ(ierr);
  ierr = VecRestoreArray(coordinatesB, &coordsB);CHKERRQ(ierr);
  ierr = DMSetCoordinatesLocal(dmB, coordinatesB);CHKERRQ(ierr);
  ierr = VecDestroy(&coordinatesB);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

Example #2

File: vsection.c Project: haubentaucher/petsc

PetscErrorCode PetscSectionGetField_Internal(PetscSection section, PetscSection sectionGlobal, Vec v, PetscInt field, PetscInt pStart, PetscInt pEnd, IS *is, Vec *subv)
{
  PetscInt      *subIndices;
  PetscInt       Nc, subSize = 0, subOff = 0, p;
  PetscErrorCode ierr;

  PetscFunctionBegin;
  ierr = PetscSectionGetFieldComponents(section, field, &Nc);CHKERRQ(ierr);
  for (p = pStart; p < pEnd; ++p) {
    PetscInt gdof, fdof = 0;

    ierr = PetscSectionGetDof(sectionGlobal, p, &gdof);CHKERRQ(ierr);
    if (gdof > 0) {ierr = PetscSectionGetFieldDof(section, p, field, &fdof);CHKERRQ(ierr);}
    subSize += fdof;
  }
  ierr = PetscMalloc1(subSize, &subIndices);CHKERRQ(ierr);
  for (p = pStart; p < pEnd; ++p) {
    PetscInt gdof, goff;

    ierr = PetscSectionGetDof(sectionGlobal, p, &gdof);CHKERRQ(ierr);
    if (gdof > 0) {
      PetscInt fdof, fc, f2, poff = 0;

      ierr = PetscSectionGetOffset(sectionGlobal, p, &goff);CHKERRQ(ierr);
      /* Can get rid of this loop by storing field information in the global section */
      for (f2 = 0; f2 < field; ++f2) {
        ierr  = PetscSectionGetFieldDof(section, p, f2, &fdof);CHKERRQ(ierr);
        poff += fdof;
      }
      ierr = PetscSectionGetFieldDof(section, p, field, &fdof);CHKERRQ(ierr);
      for (fc = 0; fc < fdof; ++fc, ++subOff) subIndices[subOff] = goff+poff+fc;
    }
  }
  ierr = ISCreateGeneral(PetscObjectComm((PetscObject) v), subSize, subIndices, PETSC_OWN_POINTER, is);CHKERRQ(ierr);
  ierr = VecGetSubVector(v, *is, subv);CHKERRQ(ierr);
  ierr = VecSetBlockSize(*subv, Nc);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}