static PetscErrorCode BuildGradientReconstruction(DM dm, PetscFV fvm, DM dmFace, PetscScalar *fgeom, DM dmCell, PetscScalar *cgeom)
{
DMLabel ghostLabel;
PetscScalar *dx, *grad, **gref;
PetscInt dim, cStart, cEnd, c, cEndInterior, maxNumFaces;
PetscErrorCode ierr;
PetscFunctionBegin;
ierr = DMPlexGetDimension(dm, &dim);CHKERRQ(ierr);
ierr = DMPlexGetHeightStratum(dm, 0, &cStart, &cEnd);CHKERRQ(ierr);
ierr = DMPlexGetHybridBounds(dm, &cEndInterior, NULL, NULL, NULL);CHKERRQ(ierr);
ierr = DMPlexGetMaxSizes(dm, &maxNumFaces, NULL);CHKERRQ(ierr);
ierr = PetscFVLeastSquaresSetMaxFaces(fvm, maxNumFaces);CHKERRQ(ierr);
ierr = DMPlexGetLabel(dm, "ghost", &ghostLabel);CHKERRQ(ierr);
ierr = PetscMalloc3(maxNumFaces*dim, &dx, maxNumFaces*dim, &grad, maxNumFaces, &gref);CHKERRQ(ierr);
for (c = cStart; c < cEndInterior; c++) {
const PetscInt *faces;
PetscInt numFaces, usedFaces, f, d;
const CellGeom *cg;
PetscBool boundary;
PetscInt ghost;
ierr = DMPlexPointLocalRead(dmCell, c, cgeom, &cg);CHKERRQ(ierr);
ierr = DMPlexGetConeSize(dm, c, &numFaces);CHKERRQ(ierr);
ierr = DMPlexGetCone(dm, c, &faces);CHKERRQ(ierr);
if (numFaces < dim) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_INCOMP,"Cell %D has only %D faces, not enough for gradient reconstruction", c, numFaces);
for (f = 0, usedFaces = 0; f < numFaces; ++f) {
const CellGeom *cg1;
FaceGeom *fg;
const PetscInt *fcells;
PetscInt ncell, side;
ierr = DMLabelGetValue(ghostLabel, faces[f], &ghost);CHKERRQ(ierr);
ierr = DMPlexIsBoundaryPoint(dm, faces[f], &boundary);CHKERRQ(ierr);
if ((ghost >= 0) || boundary) continue;
ierr = DMPlexGetSupport(dm, faces[f], &fcells);CHKERRQ(ierr);
side = (c != fcells[0]); /* c is on left=0 or right=1 of face */
ncell = fcells[!side]; /* the neighbor */
ierr = DMPlexPointLocalRef(dmFace, faces[f], fgeom, &fg);CHKERRQ(ierr);
ierr = DMPlexPointLocalRead(dmCell, ncell, cgeom, &cg1);CHKERRQ(ierr);
for (d = 0; d < dim; ++d) dx[usedFaces*dim+d] = cg1->centroid[d] - cg->centroid[d];
gref[usedFaces++] = fg->grad[side]; /* Gradient reconstruction term will go here */
}
if (!usedFaces) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_USER, "Mesh contains isolated cell (no neighbors). Is it intentional?");
ierr = PetscFVComputeGradient(fvm, usedFaces, dx, grad);CHKERRQ(ierr);
for (f = 0, usedFaces = 0; f < numFaces; ++f) {
ierr = DMLabelGetValue(ghostLabel, faces[f], &ghost);CHKERRQ(ierr);
ierr = DMPlexIsBoundaryPoint(dm, faces[f], &boundary);CHKERRQ(ierr);
if ((ghost >= 0) || boundary) continue;
for (d = 0; d < dim; ++d) gref[usedFaces][d] = grad[usedFaces*dim+d];
++usedFaces;
}
}
ierr = PetscFree3(dx, grad, gref);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
PETSC_EXTERN void PETSC_STDCALL petscfvleastsquaressetmaxfaces_(PetscFV fvm,PetscInt *maxFaces, int *__ierr ){
*__ierr = PetscFVLeastSquaresSetMaxFaces(
(PetscFV)PetscToPointer((fvm) ),*maxFaces);
}
