1 #include <petsc/private/dmpleximpl.h> /*I "petscdmplex.h" I*/ 2 #include <petscsf.h> 3 4 #include <petsc/private/petscfeimpl.h> 5 #include <petsc/private/petscfvimpl.h> 6 7 static PetscErrorCode DMPlexApplyLimiter_Internal(DM dm, DM dmCell, PetscLimiter lim, PetscInt dim, PetscInt dof, PetscInt cell, PetscInt field, PetscInt face, PetscInt fStart, PetscInt fEnd, PetscReal *cellPhi, const PetscScalar *x, const PetscScalar *cellgeom, const PetscFVCellGeom *cg, const PetscScalar *cx, const PetscScalar *cgrad) { 8 const PetscInt *children; 9 PetscInt numChildren; 10 11 PetscFunctionBegin; 12 PetscCall(DMPlexGetTreeChildren(dm, face, &numChildren, &children)); 13 if (numChildren) { 14 PetscInt c; 15 16 for (c = 0; c < numChildren; c++) { 17 PetscInt childFace = children[c]; 18 19 if (childFace >= fStart && childFace < fEnd) PetscCall(DMPlexApplyLimiter_Internal(dm, dmCell, lim, dim, dof, cell, field, childFace, fStart, fEnd, cellPhi, x, cellgeom, cg, cx, cgrad)); 20 } 21 } else { 22 PetscScalar *ncx; 23 PetscFVCellGeom *ncg; 24 const PetscInt *fcells; 25 PetscInt ncell, d; 26 PetscReal v[3]; 27 28 PetscCall(DMPlexGetSupport(dm, face, &fcells)); 29 ncell = cell == fcells[0] ? fcells[1] : fcells[0]; 30 if (field >= 0) { 31 PetscCall(DMPlexPointLocalFieldRead(dm, ncell, field, x, &ncx)); 32 } else { 33 PetscCall(DMPlexPointLocalRead(dm, ncell, x, &ncx)); 34 } 35 PetscCall(DMPlexPointLocalRead(dmCell, ncell, cellgeom, &ncg)); 36 DMPlex_WaxpyD_Internal(dim, -1, cg->centroid, ncg->centroid, v); 37 for (d = 0; d < dof; ++d) { 38 /* We use the symmetric slope limited form of Berger, Aftosmis, and Murman 2005 */ 39 PetscReal denom = DMPlex_DotD_Internal(dim, &cgrad[d * dim], v); 40 PetscReal phi, flim = 0.5 * PetscRealPart(ncx[d] - cx[d]) / denom; 41 42 PetscCall(PetscLimiterLimit(lim, flim, &phi)); 43 cellPhi[d] = PetscMin(cellPhi[d], phi); 44 } 45 } 46 PetscFunctionReturn(0); 47 } 48 49 PetscErrorCode DMPlexReconstructGradients_Internal(DM dm, PetscFV fvm, PetscInt fStart, PetscInt fEnd, Vec faceGeometry, Vec cellGeometry, Vec locX, Vec grad) { 50 DM dmFace, dmCell, dmGrad; 51 DMLabel ghostLabel; 52 PetscDS prob; 53 PetscLimiter lim; 54 const PetscScalar *facegeom, *cellgeom, *x; 55 PetscScalar *gr; 56 PetscReal *cellPhi; 57 PetscInt dim, face, cell, field, dof, cStart, cEnd, nFields; 58 59 PetscFunctionBegin; 60 PetscCall(DMGetDimension(dm, &dim)); 61 PetscCall(DMGetDS(dm, &prob)); 62 PetscCall(PetscDSGetNumFields(prob, &nFields)); 63 PetscCall(PetscDSGetFieldIndex(prob, (PetscObject)fvm, &field)); 64 PetscCall(PetscDSGetFieldSize(prob, field, &dof)); 65 PetscCall(DMGetLabel(dm, "ghost", &ghostLabel)); 66 PetscCall(PetscFVGetLimiter(fvm, &lim)); 67 PetscCall(VecGetDM(faceGeometry, &dmFace)); 68 PetscCall(VecGetArrayRead(faceGeometry, &facegeom)); 69 PetscCall(VecGetDM(cellGeometry, &dmCell)); 70 PetscCall(VecGetArrayRead(cellGeometry, &cellgeom)); 71 PetscCall(VecGetArrayRead(locX, &x)); 72 PetscCall(VecGetDM(grad, &dmGrad)); 73 PetscCall(VecZeroEntries(grad)); 74 PetscCall(VecGetArray(grad, &gr)); 75 /* Reconstruct gradients */ 76 for (face = fStart; face < fEnd; ++face) { 77 const PetscInt *cells; 78 PetscFVFaceGeom *fg; 79 PetscScalar *cx[2]; 80 PetscScalar *cgrad[2]; 81 PetscBool boundary; 82 PetscInt ghost, c, pd, d, numChildren, numCells; 83 84 PetscCall(DMLabelGetValue(ghostLabel, face, &ghost)); 85 PetscCall(DMIsBoundaryPoint(dm, face, &boundary)); 86 PetscCall(DMPlexGetTreeChildren(dm, face, &numChildren, NULL)); 87 if (ghost >= 0 || boundary || numChildren) continue; 88 PetscCall(DMPlexGetSupportSize(dm, face, &numCells)); 89 PetscCheck(numCells == 2, PETSC_COMM_SELF, PETSC_ERR_PLIB, "facet %" PetscInt_FMT " has %" PetscInt_FMT " support points: expected 2", face, numCells); 90 PetscCall(DMPlexGetSupport(dm, face, &cells)); 91 PetscCall(DMPlexPointLocalRead(dmFace, face, facegeom, &fg)); 92 for (c = 0; c < 2; ++c) { 93 if (nFields > 1) { 94 PetscCall(DMPlexPointLocalFieldRead(dm, cells[c], field, x, &cx[c])); 95 } else { 96 PetscCall(DMPlexPointLocalRead(dm, cells[c], x, &cx[c])); 97 } 98 PetscCall(DMPlexPointGlobalRef(dmGrad, cells[c], gr, &cgrad[c])); 99 } 100 for (pd = 0; pd < dof; ++pd) { 101 PetscScalar delta = cx[1][pd] - cx[0][pd]; 102 103 for (d = 0; d < dim; ++d) { 104 if (cgrad[0]) cgrad[0][pd * dim + d] += fg->grad[0][d] * delta; 105 if (cgrad[1]) cgrad[1][pd * dim + d] -= fg->grad[1][d] * delta; 106 } 107 } 108 } 109 /* Limit interior gradients (using cell-based loop because it generalizes better to vector limiters) */ 110 PetscCall(DMPlexGetSimplexOrBoxCells(dm, 0, &cStart, &cEnd)); 111 PetscCall(DMGetWorkArray(dm, dof, MPIU_REAL, &cellPhi)); 112 for (cell = (dmGrad && lim) ? cStart : cEnd; cell < cEnd; ++cell) { 113 const PetscInt *faces; 114 PetscScalar *cx; 115 PetscFVCellGeom *cg; 116 PetscScalar *cgrad; 117 PetscInt coneSize, f, pd, d; 118 119 PetscCall(DMPlexGetConeSize(dm, cell, &coneSize)); 120 PetscCall(DMPlexGetCone(dm, cell, &faces)); 121 if (nFields > 1) { 122 PetscCall(DMPlexPointLocalFieldRead(dm, cell, field, x, &cx)); 123 } else { 124 PetscCall(DMPlexPointLocalRead(dm, cell, x, &cx)); 125 } 126 PetscCall(DMPlexPointLocalRead(dmCell, cell, cellgeom, &cg)); 127 PetscCall(DMPlexPointGlobalRef(dmGrad, cell, gr, &cgrad)); 128 if (!cgrad) continue; /* Unowned overlap cell, we do not compute */ 129 /* Limiter will be minimum value over all neighbors */ 130 for (d = 0; d < dof; ++d) cellPhi[d] = PETSC_MAX_REAL; 131 for (f = 0; f < coneSize; ++f) PetscCall(DMPlexApplyLimiter_Internal(dm, dmCell, lim, dim, dof, cell, nFields > 1 ? field : -1, faces[f], fStart, fEnd, cellPhi, x, cellgeom, cg, cx, cgrad)); 132 /* Apply limiter to gradient */ 133 for (pd = 0; pd < dof; ++pd) /* Scalar limiter applied to each component separately */ 134 for (d = 0; d < dim; ++d) cgrad[pd * dim + d] *= cellPhi[pd]; 135 } 136 PetscCall(DMRestoreWorkArray(dm, dof, MPIU_REAL, &cellPhi)); 137 PetscCall(VecRestoreArrayRead(faceGeometry, &facegeom)); 138 PetscCall(VecRestoreArrayRead(cellGeometry, &cellgeom)); 139 PetscCall(VecRestoreArrayRead(locX, &x)); 140 PetscCall(VecRestoreArray(grad, &gr)); 141 PetscFunctionReturn(0); 142 } 143 144 /*@ 145 DMPlexReconstructGradientsFVM - reconstruct the gradient of a vector using a finite volume method. 146 147 Input Parameters: 148 + dm - the mesh 149 - locX - the local representation of the vector 150 151 Output Parameter: 152 . grad - the global representation of the gradient 153 154 Level: developer 155 156 .seealso: `DMPlexGetGradientDM()` 157 @*/ 158 PetscErrorCode DMPlexReconstructGradientsFVM(DM dm, Vec locX, Vec grad) { 159 PetscDS prob; 160 PetscInt Nf, f, fStart, fEnd; 161 PetscBool useFVM = PETSC_FALSE; 162 PetscFV fvm = NULL; 163 Vec faceGeometryFVM, cellGeometryFVM; 164 PetscFVCellGeom *cgeomFVM = NULL; 165 PetscFVFaceGeom *fgeomFVM = NULL; 166 DM dmGrad = NULL; 167 168 PetscFunctionBegin; 169 PetscCall(DMGetDS(dm, &prob)); 170 PetscCall(PetscDSGetNumFields(prob, &Nf)); 171 for (f = 0; f < Nf; ++f) { 172 PetscObject obj; 173 PetscClassId id; 174 175 PetscCall(PetscDSGetDiscretization(prob, f, &obj)); 176 PetscCall(PetscObjectGetClassId(obj, &id)); 177 if (id == PETSCFV_CLASSID) { 178 useFVM = PETSC_TRUE; 179 fvm = (PetscFV)obj; 180 } 181 } 182 PetscCheck(useFVM, PetscObjectComm((PetscObject)dm), PETSC_ERR_SUP, "This dm does not have a finite volume discretization"); 183 PetscCall(DMPlexGetDataFVM(dm, fvm, &cellGeometryFVM, &faceGeometryFVM, &dmGrad)); 184 PetscCheck(dmGrad, PetscObjectComm((PetscObject)dm), PETSC_ERR_SUP, "This dm's finite volume discretization does not reconstruct gradients"); 185 PetscCall(VecGetArrayRead(faceGeometryFVM, (const PetscScalar **)&fgeomFVM)); 186 PetscCall(VecGetArrayRead(cellGeometryFVM, (const PetscScalar **)&cgeomFVM)); 187 PetscCall(DMPlexGetHeightStratum(dm, 1, &fStart, &fEnd)); 188 PetscCall(DMPlexReconstructGradients_Internal(dm, fvm, fStart, fEnd, faceGeometryFVM, cellGeometryFVM, locX, grad)); 189 PetscFunctionReturn(0); 190 } 191