xref: /honee/src/diff_flux_projection.c (revision f2027640766d6972bdb921a7fd42c28c0ec88d42)
1 // SPDX-FileCopyrightText: Copyright (c) 2017-2024, HONEE contributors.
2 // SPDX-License-Identifier: Apache-2.0 OR BSD-2-Clause
3 /// @file
4 /// Functions for setting up and projecting the divergence of the diffusive flux
5 
6 #include "../qfunctions/diff_flux_projection.h"
7 
8 #include <petscdmplex.h>
9 
10 #include <navierstokes.h>
11 
12 const char *const DivDiffFluxProjectionMethods[] = {"NONE", "DIRECT", "INDIRECT", "DivDiffFluxProjectionMethod", "DIV_DIFF_FLUX_PROJ_", NULL};
13 
14 /**
15   @brief Create `DivDiffFluxProjectionData` for solution DM in `honee`
16 
17   @param[in]  honee               `Honee` context
18   @param[in]  divFdiffproj_method Method used to perform the divergence of diffusive flux method (can be `DIV_DIFF_FLUX_PROJ_NONE`)
19   @param[in]  num_diff_flux_comps Number of components that makes up the diffusive flux (e.g. 1 for scalar advection-diffusion)
20   @param[out] diff_flux_proj      The `DivDiffFluxProjectionData` object created, or set to `NULL` if `divFdiffproj_method = DIV_DIFF_FLUX_PROJ_NONE`
21 **/
22 PetscErrorCode DivDiffFluxProjectionCreate(Honee honee, DivDiffFluxProjectionMethod divFdiffproj_method, PetscInt num_diff_flux_comps,
23                                            DivDiffFluxProjectionData *diff_flux_proj) {
24   PetscInt                  label_value = 0, height = 0, dm_field = 0, dim, degree = honee->app_ctx->degree, q_extra = honee->app_ctx->q_extra;
25   DMLabel                   domain_label = NULL;
26   DivDiffFluxProjectionData diff_flux_proj_;
27   NodalProjectionData       projection;
28 
29   PetscFunctionBeginUser;
30   if (divFdiffproj_method == DIV_DIFF_FLUX_PROJ_NONE) {
31     *diff_flux_proj = NULL;
32     PetscFunctionReturn(PETSC_SUCCESS);
33   }
34   PetscCall(PetscNew(&projection));
35   PetscCall(PetscNew(&diff_flux_proj_));
36   *diff_flux_proj_ = (struct DivDiffFluxProjectionData_){
37       .method              = divFdiffproj_method,
38       .num_diff_flux_comps = num_diff_flux_comps,
39       .projection          = projection,
40   };
41 
42   PetscCall(DMClone(honee->dm, &projection->dm));
43   PetscCall(DMSetMatrixPreallocateSkip(projection->dm, PETSC_TRUE));
44   PetscCall(DMGetDimension(projection->dm, &dim));
45   switch (diff_flux_proj_->method) {
46     case DIV_DIFF_FLUX_PROJ_DIRECT: {
47       projection->num_comp = diff_flux_proj_->num_diff_flux_comps;
48       PetscCall(PetscObjectSetName((PetscObject)projection->dm, "DivDiffFluxProj"));
49       PetscCall(DMSetupByOrder_FEM(PETSC_TRUE, PETSC_TRUE, degree, 1, q_extra, 1, &projection->num_comp, projection->dm));
50 
51       PetscCall(DMPlexCeedElemRestrictionCreate(honee->ceed, projection->dm, domain_label, label_value, height, dm_field,
52                                                 &diff_flux_proj_->elem_restr_div_diff_flux));
53       PetscCallCeed(honee->ceed,
54                     CeedElemRestrictionCreateVector(diff_flux_proj_->elem_restr_div_diff_flux, &diff_flux_proj_->div_diff_flux_ceed, NULL));
55       PetscCall(CreateBasisFromPlex(honee->ceed, projection->dm, domain_label, label_value, height, dm_field, &diff_flux_proj_->basis_div_diff_flux));
56       diff_flux_proj_->eval_mode_div_diff_flux = CEED_EVAL_INTERP;
57 
58       {  // Create face labels on projection->dm for boundary integrals
59         DMLabel  face_sets_label;
60         PetscInt num_face_set_values, *face_set_values;
61 
62         PetscCall(DMGetLabel(honee->dm, "Face Sets", &face_sets_label));
63         PetscCall(DMLabelCreateGlobalValueArray(honee->dm, face_sets_label, &num_face_set_values, &face_set_values));
64         for (PetscInt f = 0; f < num_face_set_values; f++) {
65           DMLabel face_orientation_label;
66           char   *face_orientation_label_name;
67 
68           PetscCall(DMPlexCreateFaceLabel(honee->dm, face_set_values[f], &face_orientation_label_name));
69           PetscCall(DMGetLabel(honee->dm, face_orientation_label_name, &face_orientation_label));
70           PetscCall(DMAddLabel(projection->dm, face_orientation_label));
71           PetscCall(PetscFree(face_orientation_label_name));
72         }
73         PetscCall(PetscFree(face_set_values));
74       }
75     } break;
76     case DIV_DIFF_FLUX_PROJ_INDIRECT: {
77       projection->num_comp = diff_flux_proj_->num_diff_flux_comps * dim;
78       PetscCall(PetscObjectSetName((PetscObject)projection->dm, "DiffFluxProj"));
79       PetscCall(DMSetupByOrder_FEM(PETSC_TRUE, PETSC_TRUE, degree, 1, q_extra, 1, &projection->num_comp, projection->dm));
80 
81       PetscCall(DMPlexCeedElemRestrictionQDataCreate(honee->ceed, projection->dm, domain_label, label_value, height,
82                                                      diff_flux_proj_->num_diff_flux_comps, &diff_flux_proj_->elem_restr_div_diff_flux));
83       PetscCallCeed(honee->ceed,
84                     CeedElemRestrictionCreateVector(diff_flux_proj_->elem_restr_div_diff_flux, &diff_flux_proj_->div_diff_flux_ceed, NULL));
85       diff_flux_proj_->basis_div_diff_flux     = CEED_BASIS_NONE;
86       diff_flux_proj_->eval_mode_div_diff_flux = CEED_EVAL_NONE;
87     } break;
88     case DIV_DIFF_FLUX_PROJ_NONE:
89       SETERRQ(honee->comm, PETSC_ERR_ARG_WRONG, "Should not reach here with div_diff_flux_projection_method %s",
90               DivDiffFluxProjectionMethods[divFdiffproj_method]);
91       break;
92   }
93   *diff_flux_proj = diff_flux_proj_;
94   PetscFunctionReturn(PETSC_SUCCESS);
95 };
96 
97 /**
98   @brief Return the objects required for the Divergence of Diffusive flux to be read by a `CeedOperator`
99 
100   @param[in]  diff_flux_proj Projection object
101   @param[out] elem_restr     Element restriction for the divergence of diffusive flux, or `NULL`
102   @param[out] basis          Basis for the divergence of diffusive flux, or `NULL`
103   @param[out] vector         Vector for the divergence of diffusive flux, or `NULL`
104   @param[out] eval_mode      Eval mode for the divergence of diffusive flux, or `NULL`
105 **/
106 PetscErrorCode DivDiffFluxProjectionGetOperatorFieldData(DivDiffFluxProjectionData diff_flux_proj, CeedElemRestriction *elem_restr, CeedBasis *basis,
107                                                          CeedVector *vector, CeedEvalMode *eval_mode) {
108   Ceed ceed = CeedVectorReturnCeed(diff_flux_proj->div_diff_flux_ceed);
109 
110   PetscFunctionBeginUser;
111   if (elem_restr) PetscCallCeed(ceed, CeedElemRestrictionReferenceCopy(diff_flux_proj->elem_restr_div_diff_flux, elem_restr));
112   if (basis) PetscCallCeed(ceed, CeedBasisReferenceCopy(diff_flux_proj->basis_div_diff_flux, basis));
113   if (vector) PetscCallCeed(ceed, CeedVectorReferenceCopy(diff_flux_proj->div_diff_flux_ceed, vector));
114   if (eval_mode) *eval_mode = diff_flux_proj->eval_mode_div_diff_flux;
115   PetscFunctionReturn(PETSC_SUCCESS);
116 }
117 
118 /**
119   @brief Setup direct projection of divergence of diffusive flux
120 
121   @param[in]     honee          `Honee` context
122   @param[in,out] diff_flux_proj Flux projection object to setup
123 **/
124 static PetscErrorCode DivDiffFluxProjectionSetup_Direct(Honee honee, DivDiffFluxProjectionData diff_flux_proj) {
125   Ceed                ceed       = honee->ceed;
126   NodalProjectionData projection = diff_flux_proj->projection;
127   MPI_Comm            comm       = PetscObjectComm((PetscObject)projection->dm);
128 
129   PetscFunctionBeginUser;
130   {  // Create Projection RHS OperatorApplyContext
131     CeedOperator op_rhs;
132 
133     PetscCheck(diff_flux_proj->CreateRHSOperator_Direct, comm, PETSC_ERR_ARG_WRONGSTATE,
134                "Must define CreateRHSOperator_Direct to use indirect div_diff_flux projection");
135     PetscCall(diff_flux_proj->CreateRHSOperator_Direct(honee, diff_flux_proj, &op_rhs));
136     PetscCall(DMCreateLocalVector(projection->dm, &diff_flux_proj->DivDiffFlux_loc));
137     diff_flux_proj->ceed_vec_has_array = PETSC_FALSE;
138     PetscCall(OperatorApplyContextCreate(honee->dm, projection->dm, ceed, op_rhs, NULL, NULL, NULL, diff_flux_proj->DivDiffFlux_loc,
139                                          &projection->l2_rhs_ctx));
140     PetscCallCeed(ceed, CeedOperatorDestroy(&op_rhs));
141   }
142 
143   {  // -- Build Mass operator
144     CeedQFunction       qf_mass;
145     CeedOperator        op_mass;
146     CeedBasis           basis_div_diff_flux             = NULL;
147     CeedElemRestriction elem_restr_div_diff_flux_volume = NULL, elem_restr_qd;
148     CeedVector          q_data;
149     CeedInt             q_data_size;
150     PetscInt            label_value  = 0;
151     DMLabel             domain_label = NULL;
152 
153     PetscCall(DivDiffFluxProjectionGetOperatorFieldData(diff_flux_proj, &elem_restr_div_diff_flux_volume, &basis_div_diff_flux, NULL, NULL));
154     PetscCall(QDataGet(ceed, projection->dm, domain_label, label_value, honee->elem_restr_x, honee->basis_x, honee->x_coord, &elem_restr_qd, &q_data,
155                        &q_data_size));
156 
157     PetscCall(HoneeMassQFunctionCreate(ceed, projection->num_comp, q_data_size, &qf_mass));
158     PetscCallCeed(ceed, CeedOperatorCreate(ceed, qf_mass, NULL, NULL, &op_mass));
159     PetscCallCeed(ceed, CeedOperatorSetField(op_mass, "u", elem_restr_div_diff_flux_volume, basis_div_diff_flux, CEED_VECTOR_ACTIVE));
160     PetscCallCeed(ceed, CeedOperatorSetField(op_mass, "qdata", elem_restr_qd, CEED_BASIS_NONE, q_data));
161     PetscCallCeed(ceed, CeedOperatorSetField(op_mass, "v", elem_restr_div_diff_flux_volume, basis_div_diff_flux, CEED_VECTOR_ACTIVE));
162 
163     {  // -- Setup KSP for L^2 projection
164       Mat mat_mass;
165 
166       PetscCall(MatCreateCeed(projection->dm, projection->dm, op_mass, NULL, &mat_mass));
167 
168       PetscCall(KSPCreate(comm, &projection->ksp));
169       PetscCall(KSPSetOptionsPrefix(projection->ksp, "div_diff_flux_projection_"));
170       {  // lumped by default
171         PC pc;
172         PetscCall(KSPGetPC(projection->ksp, &pc));
173         PetscCall(PCSetType(pc, PCJACOBI));
174         PetscCall(PCJacobiSetType(pc, PC_JACOBI_ROWSUM));
175         PetscCall(KSPSetType(projection->ksp, KSPPREONLY));
176       }
177       PetscCall(KSPSetFromOptions_WithMatCeed(projection->ksp, mat_mass));
178       PetscCall(MatDestroy(&mat_mass));
179     }
180 
181     PetscCallCeed(ceed, CeedElemRestrictionDestroy(&elem_restr_div_diff_flux_volume));
182     PetscCallCeed(ceed, CeedBasisDestroy(&basis_div_diff_flux));
183     PetscCallCeed(ceed, CeedVectorDestroy(&q_data));
184     PetscCallCeed(ceed, CeedElemRestrictionDestroy(&elem_restr_qd));
185     PetscCallCeed(ceed, CeedQFunctionDestroy(&qf_mass));
186     PetscCallCeed(ceed, CeedOperatorDestroy(&op_mass));
187   }
188   PetscFunctionReturn(PETSC_SUCCESS);
189 }
190 
191 /**
192   @brief Setup indirect projection of divergence of diffusive flux
193 
194   @param[in]     honee          `Honee` context
195   @param[in,out] diff_flux_proj Flux projection object to setup
196 **/
197 static PetscErrorCode DivDiffFluxProjectionSetup_Indirect(Honee honee, DivDiffFluxProjectionData diff_flux_proj) {
198   Ceed                ceed       = honee->ceed;
199   NodalProjectionData projection = diff_flux_proj->projection;
200   CeedBasis           basis_diff_flux;
201   CeedElemRestriction elem_restr_diff_flux, elem_restr_qd;
202   CeedVector          q_data;
203   CeedInt             q_data_size;
204   MPI_Comm            comm = PetscObjectComm((PetscObject)projection->dm);
205 
206   PetscFunctionBeginUser;
207   {
208     PetscInt label_value = 0, height = 0, dm_field = 0;
209     DMLabel  domain_label = NULL;
210 
211     PetscCall(DMPlexCeedElemRestrictionCreate(ceed, projection->dm, domain_label, label_value, height, dm_field, &elem_restr_diff_flux));
212     PetscCall(CreateBasisFromPlex(ceed, projection->dm, domain_label, label_value, height, dm_field, &basis_diff_flux));
213     PetscCall(QDataGet(ceed, projection->dm, domain_label, label_value, honee->elem_restr_x, honee->basis_x, honee->x_coord, &elem_restr_qd, &q_data,
214                        &q_data_size));
215   }
216 
217   {
218     CeedOperator op_rhs;
219 
220     PetscCheck(diff_flux_proj->CreateRHSOperator_Indirect, comm, PETSC_ERR_ARG_WRONGSTATE,
221                "Must define CreateRHSOperator_Indirect to use indirect div_diff_flux projection");
222     PetscCall(diff_flux_proj->CreateRHSOperator_Indirect(honee, diff_flux_proj, &op_rhs));
223     PetscCall(OperatorApplyContextCreate(honee->dm, projection->dm, ceed, op_rhs, NULL, NULL, NULL, NULL, &projection->l2_rhs_ctx));
224     PetscCallCeed(ceed, CeedOperatorDestroy(&op_rhs));
225   }
226 
227   {  // -- Build Mass operator
228     CeedQFunction qf_mass;
229     CeedOperator  op_mass;
230 
231     PetscCall(HoneeMassQFunctionCreate(ceed, projection->num_comp, q_data_size, &qf_mass));
232     PetscCallCeed(ceed, CeedOperatorCreate(ceed, qf_mass, NULL, NULL, &op_mass));
233     PetscCallCeed(ceed, CeedOperatorSetField(op_mass, "u", elem_restr_diff_flux, basis_diff_flux, CEED_VECTOR_ACTIVE));
234     PetscCallCeed(ceed, CeedOperatorSetField(op_mass, "qdata", elem_restr_qd, CEED_BASIS_NONE, q_data));
235     PetscCallCeed(ceed, CeedOperatorSetField(op_mass, "v", elem_restr_diff_flux, basis_diff_flux, CEED_VECTOR_ACTIVE));
236 
237     {  // -- Setup KSP for L^2 projection
238       Mat mat_mass;
239 
240       PetscCall(MatCreateCeed(projection->dm, projection->dm, op_mass, NULL, &mat_mass));
241 
242       PetscCall(KSPCreate(comm, &projection->ksp));
243       PetscCall(KSPSetOptionsPrefix(projection->ksp, "div_diff_flux_projection_"));
244       {  // lumped by default
245         PC pc;
246         PetscCall(KSPGetPC(projection->ksp, &pc));
247         PetscCall(PCSetType(pc, PCJACOBI));
248         PetscCall(PCJacobiSetType(pc, PC_JACOBI_ROWSUM));
249         PetscCall(KSPSetType(projection->ksp, KSPPREONLY));
250       }
251       PetscCall(KSPSetFromOptions_WithMatCeed(projection->ksp, mat_mass));
252       PetscCall(MatDestroy(&mat_mass));
253     }
254     PetscCallCeed(ceed, CeedQFunctionDestroy(&qf_mass));
255     PetscCallCeed(ceed, CeedOperatorDestroy(&op_mass));
256   }
257 
258   {  // Create OperatorApplyContext to calculate divergence at quadrature points
259     CeedQFunction       qf_calc_divergence = NULL;
260     CeedOperator        op_calc_divergence;
261     CeedElemRestriction elem_restr_div_diff_flux = NULL;
262     PetscInt            dim;
263 
264     PetscCall(DMGetDimension(projection->dm, &dim));
265     PetscCall(DivDiffFluxProjectionGetOperatorFieldData(diff_flux_proj, &elem_restr_div_diff_flux, NULL, NULL, NULL));
266 
267     switch (dim) {
268       case 2:
269         switch (diff_flux_proj->num_diff_flux_comps) {
270           case 1:
271             PetscCallCeed(ceed,
272                           CeedQFunctionCreateInterior(ceed, 1, ComputeDivDiffusiveFlux2D_1, ComputeDivDiffusiveFlux2D_1_loc, &qf_calc_divergence));
273             break;
274         }
275         break;
276       case 3:
277         switch (diff_flux_proj->num_diff_flux_comps) {
278           case 1:
279             PetscCallCeed(ceed,
280                           CeedQFunctionCreateInterior(ceed, 1, ComputeDivDiffusiveFlux3D_1, ComputeDivDiffusiveFlux3D_1_loc, &qf_calc_divergence));
281             break;
282           case 4:
283             PetscCallCeed(ceed,
284                           CeedQFunctionCreateInterior(ceed, 1, ComputeDivDiffusiveFlux3D_4, ComputeDivDiffusiveFlux3D_4_loc, &qf_calc_divergence));
285             break;
286         }
287         break;
288     }
289     PetscCheck(qf_calc_divergence, comm, PETSC_ERR_SUP,
290                "QFunction for calculating divergence of diffusive flux does not exist for"
291                " %" PetscInt_FMT " dimensional grid and %" PetscInt_FMT
292                " number of components.\nA new qfunction can be easily added; see source code for pattern.",
293                dim, diff_flux_proj->num_diff_flux_comps);
294 
295     PetscCallCeed(ceed, CeedQFunctionAddInput(qf_calc_divergence, "Grad F_diff", projection->num_comp * dim, CEED_EVAL_GRAD));
296     PetscCallCeed(ceed, CeedQFunctionAddInput(qf_calc_divergence, "qdata", q_data_size, CEED_EVAL_NONE));
297     PetscCallCeed(ceed, CeedQFunctionAddOutput(qf_calc_divergence, "Div F_diff", diff_flux_proj->num_diff_flux_comps, CEED_EVAL_NONE));
298 
299     PetscCallCeed(ceed, CeedOperatorCreate(ceed, qf_calc_divergence, NULL, NULL, &op_calc_divergence));
300     PetscCallCeed(ceed, CeedOperatorSetField(op_calc_divergence, "Grad F_diff", elem_restr_diff_flux, basis_diff_flux, CEED_VECTOR_ACTIVE));
301     PetscCallCeed(ceed, CeedOperatorSetField(op_calc_divergence, "qdata", elem_restr_qd, CEED_BASIS_NONE, q_data));
302     PetscCallCeed(
303         ceed, CeedOperatorSetField(op_calc_divergence, "Div F_diff", elem_restr_div_diff_flux, CEED_BASIS_NONE, diff_flux_proj->div_diff_flux_ceed));
304 
305     PetscCall(OperatorApplyContextCreate(projection->dm, NULL, ceed, op_calc_divergence, NULL, CEED_VECTOR_NONE, NULL, NULL,
306                                          &diff_flux_proj->calc_div_diff_flux));
307 
308     PetscCallCeed(ceed, CeedElemRestrictionDestroy(&elem_restr_div_diff_flux));
309     PetscCallCeed(ceed, CeedQFunctionDestroy(&qf_calc_divergence));
310     PetscCallCeed(ceed, CeedOperatorDestroy(&op_calc_divergence));
311   }
312   PetscCallCeed(ceed, CeedBasisDestroy(&basis_diff_flux));
313   PetscCallCeed(ceed, CeedVectorDestroy(&q_data));
314   PetscCallCeed(ceed, CeedElemRestrictionDestroy(&elem_restr_qd));
315   PetscCallCeed(ceed, CeedElemRestrictionDestroy(&elem_restr_diff_flux));
316   PetscFunctionReturn(PETSC_SUCCESS);
317 }
318 
319 /**
320   @brief Setup projection of divergence of diffusive flux
321 
322   @param[in]     honee          `Honee` context
323   @param[in,out] diff_flux_proj Flux projection object to setup
324 **/
325 PetscErrorCode DivDiffFluxProjectionSetup(Honee honee, DivDiffFluxProjectionData diff_flux_proj) {
326   PetscFunctionBeginUser;
327   switch (honee->app_ctx->divFdiffproj_method) {
328     case DIV_DIFF_FLUX_PROJ_DIRECT:
329       PetscCall(DivDiffFluxProjectionSetup_Direct(honee, diff_flux_proj));
330       break;
331     case DIV_DIFF_FLUX_PROJ_INDIRECT:
332       PetscCall(DivDiffFluxProjectionSetup_Indirect(honee, diff_flux_proj));
333       break;
334     case DIV_DIFF_FLUX_PROJ_NONE:
335       SETERRQ(PetscObjectComm((PetscObject)honee->dm), PETSC_ERR_ARG_WRONG, "Should not reach here with div_diff_flux_projection_method %s",
336               DivDiffFluxProjectionMethods[honee->app_ctx->divFdiffproj_method]);
337       break;
338   }
339   PetscFunctionReturn(PETSC_SUCCESS);
340 }
341 
342 /**
343   @brief Project the divergence of diffusive flux
344 
345   This implicitly sets the `CeedVector` input (`div_diff_flux_ceed`) to the divergence of diffusive flux.
346 
347   @param[in]  diff_flux_proj `NodalProjectionData` for the projection
348   @param[in]  Q_loc          Localized solution vector
349 **/
350 PetscErrorCode DivDiffFluxProjectionApply(DivDiffFluxProjectionData diff_flux_proj, Vec Q_loc) {
351   NodalProjectionData projection = diff_flux_proj->projection;
352 
353   PetscFunctionBeginUser;
354   PetscCall(PetscLogEventBegin(HONEE_DivDiffFluxProjection, Q_loc, 0, 0, 0));
355   switch (diff_flux_proj->method) {
356     case DIV_DIFF_FLUX_PROJ_DIRECT: {
357       Vec DivDiffFlux, RHS;
358 
359       PetscCall(DMGetGlobalVector(projection->dm, &DivDiffFlux));
360       PetscCall(DMGetGlobalVector(projection->dm, &RHS));
361       if (diff_flux_proj->ceed_vec_has_array) {
362         PetscCall(VecReadCeedToPetsc(diff_flux_proj->div_diff_flux_ceed, diff_flux_proj->DivDiffFlux_memtype, diff_flux_proj->DivDiffFlux_loc));
363         diff_flux_proj->ceed_vec_has_array = PETSC_FALSE;
364       }
365       PetscCall(ApplyCeedOperatorLocalToGlobal(Q_loc, RHS, projection->l2_rhs_ctx));
366       PetscCall(VecViewFromOptions(DivDiffFlux, NULL, "-div_diff_flux_projection_rhs_view"));
367 
368       {
369         // Run PCApply manually if using ksp_type preonly -pc_type jacobi
370         // This is to avoid an AllReduce call in KSPSolve_Preonly, which causes significant slowdowns for lumped mass matrix solves.
371         // See https://gitlab.com/petsc/petsc/-/merge_requests/8048 for more details and a possible fix
372         PC        pc;
373         PetscBool ispreonly, isjacobi;
374         PetscCall(KSPGetPC(projection->ksp, &pc));
375         PetscCall(PetscObjectTypeCompare((PetscObject)projection->ksp, KSPPREONLY, &ispreonly));
376         PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCJACOBI, &isjacobi));
377         if (ispreonly && isjacobi) PetscCall(PCApply(pc, RHS, DivDiffFlux));
378         else PetscCall(KSPSolve(projection->ksp, RHS, DivDiffFlux));
379       }
380       PetscCall(VecViewFromOptions(DivDiffFlux, NULL, "-div_diff_flux_projection_view"));
381 
382       PetscCall(DMGlobalToLocal(projection->dm, DivDiffFlux, INSERT_VALUES, diff_flux_proj->DivDiffFlux_loc));
383       PetscCall(VecReadPetscToCeed(diff_flux_proj->DivDiffFlux_loc, &diff_flux_proj->DivDiffFlux_memtype, diff_flux_proj->div_diff_flux_ceed));
384       diff_flux_proj->ceed_vec_has_array = PETSC_TRUE;
385 
386       PetscCall(DMRestoreGlobalVector(projection->dm, &RHS));
387       PetscCall(DMRestoreGlobalVector(projection->dm, &DivDiffFlux));
388       break;
389     }
390     case DIV_DIFF_FLUX_PROJ_INDIRECT: {
391       Vec DiffFlux, RHS;
392 
393       PetscCall(DMGetGlobalVector(projection->dm, &DiffFlux));
394       PetscCall(DMGetGlobalVector(projection->dm, &RHS));
395       PetscCall(ApplyCeedOperatorLocalToGlobal(Q_loc, RHS, projection->l2_rhs_ctx));
396       PetscCall(VecViewFromOptions(DiffFlux, NULL, "-div_diff_flux_projection_rhs_view"));
397 
398       {
399         // Run PCApply manually if using -ksp_type preonly -pc_type jacobi
400         // This is to avoid an AllReduce call in KSPSolve_Preonly, which causes significant slowdowns for lumped mass matrix solves.
401         // See https://gitlab.com/petsc/petsc/-/merge_requests/8048 for more details and a possible fix
402         PC        pc;
403         PetscBool ispreonly, isjacobi;
404         PetscCall(KSPGetPC(projection->ksp, &pc));
405         PetscCall(PetscObjectTypeCompare((PetscObject)projection->ksp, KSPPREONLY, &ispreonly));
406         PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCJACOBI, &isjacobi));
407         if (ispreonly && isjacobi) PetscCall(PCApply(pc, RHS, DiffFlux));
408         else PetscCall(KSPSolve(projection->ksp, RHS, DiffFlux));
409       }
410       PetscCall(VecViewFromOptions(DiffFlux, NULL, "-div_diff_flux_projection_view"));
411 
412       PetscCall(ApplyCeedOperatorGlobalToLocal(DiffFlux, NULL, diff_flux_proj->calc_div_diff_flux));
413       PetscCall(DMRestoreGlobalVector(projection->dm, &RHS));
414       PetscCall(DMRestoreGlobalVector(projection->dm, &DiffFlux));
415     } break;
416     case DIV_DIFF_FLUX_PROJ_NONE:
417       SETERRQ(PetscObjectComm((PetscObject)projection->dm), PETSC_ERR_ARG_WRONG, "Should not reach here with div_diff_flux_projection_method %s",
418               DivDiffFluxProjectionMethods[diff_flux_proj->method]);
419       break;
420   }
421   PetscCall(PetscLogEventEnd(HONEE_DivDiffFluxProjection, Q_loc, 0, 0, 0));
422   PetscFunctionReturn(PETSC_SUCCESS);
423 }
424 
425 /**
426   @brief Destroy `DivDiffFluxProjectionData` object
427 
428   @param[in,out] diff_flux_proj Object to destroy
429 **/
430 PetscErrorCode DivDiffFluxProjectionDataDestroy(DivDiffFluxProjectionData diff_flux_proj) {
431   PetscFunctionBeginUser;
432   if (diff_flux_proj == NULL) PetscFunctionReturn(PETSC_SUCCESS);
433   Ceed ceed = CeedVectorReturnCeed(diff_flux_proj->div_diff_flux_ceed);
434 
435   PetscCall(NodalProjectionDataDestroy(&diff_flux_proj->projection));
436   PetscCall(OperatorApplyContextDestroy(diff_flux_proj->calc_div_diff_flux));
437   if (diff_flux_proj->ceed_vec_has_array) {
438     PetscCall(VecReadCeedToPetsc(diff_flux_proj->div_diff_flux_ceed, diff_flux_proj->DivDiffFlux_memtype, diff_flux_proj->DivDiffFlux_loc));
439     diff_flux_proj->ceed_vec_has_array = PETSC_FALSE;
440   }
441   PetscCallCeed(ceed, CeedVectorDestroy(&diff_flux_proj->div_diff_flux_ceed));
442   PetscCallCeed(ceed, CeedElemRestrictionDestroy(&diff_flux_proj->elem_restr_div_diff_flux));
443   PetscCallCeed(ceed, CeedBasisDestroy(&diff_flux_proj->basis_div_diff_flux));
444   PetscCall(VecDestroy(&diff_flux_proj->DivDiffFlux_loc));
445   PetscCall(PetscFree(diff_flux_proj));
446   PetscFunctionReturn(PETSC_SUCCESS);
447 }
448