xref: /honee/src/differential_filter.c (revision 9ed3d70d58d93bd474ae216081539cf94addd4d0) 
1 // Copyright (c) 2017-2023, Lawrence Livermore National Security, LLC and other CEED contributors.
2 // All Rights Reserved. See the top-level LICENSE and NOTICE files for details.
3 //
4 // SPDX-License-Identifier: BSD-2-Clause
5 //
6 // This file is part of CEED:  http://github.com/ceed
7 /// @file
8 /// Functions for setting up and performing differential filtering
9 
10 #include "../qfunctions/differential_filter.h"
11 
12 #include <petscdmplex.h>
13 
14 #include "../navierstokes.h"
15 
16 // @brief Create RHS and LHS operators for differential filtering
17 PetscErrorCode DifferentialFilterCreateOperators(Ceed ceed, User user, CeedData ceed_data, CeedQFunctionContext diff_filter_qfctx) {
18   DiffFilterData diff_filter = user->diff_filter;
19   DM             dm_filter   = diff_filter->dm_filter;
20   CeedInt        num_comp_q, num_comp_qd, num_comp_x;
21   PetscInt       dim;
22 
23   PetscFunctionBeginUser;
24   PetscCall(DMGetDimension(user->dm, &dim));
25   PetscCallCeed(ceed, CeedElemRestrictionGetNumComponents(ceed_data->elem_restr_x, &num_comp_x));
26   PetscCallCeed(ceed, CeedElemRestrictionGetNumComponents(ceed_data->elem_restr_q, &num_comp_q));
27   PetscCallCeed(ceed, CeedElemRestrictionGetNumComponents(ceed_data->elem_restr_qd_i, &num_comp_qd));
28 
29   {  // -- Create RHS MatopApplyContext
30     CeedQFunction qf_rhs;
31     CeedOperator  op_rhs;
32     switch (user->phys->state_var) {
33       case STATEVAR_PRIMITIVE:
34         PetscCallCeed(ceed, CeedQFunctionCreateInterior(ceed, 1, DifferentialFilter_RHS_Prim, DifferentialFilter_RHS_Prim_loc, &qf_rhs));
35         break;
36       case STATEVAR_CONSERVATIVE:
37         PetscCallCeed(ceed, CeedQFunctionCreateInterior(ceed, 1, DifferentialFilter_RHS_Conserv, DifferentialFilter_RHS_Conserv_loc, &qf_rhs));
38         break;
39       default:
40         SETERRQ(PetscObjectComm((PetscObject)user->dm), PETSC_ERR_SUP, "Differential filtering not available for chosen state variable");
41     }
42     if (diff_filter->do_mms_test) {
43       PetscCallCeed(ceed, CeedQFunctionDestroy(&qf_rhs));
44       PetscCallCeed(ceed, CeedQFunctionCreateInterior(ceed, 1, DifferentialFilter_MMS_RHS, DifferentialFilter_MMS_RHS_loc, &qf_rhs));
45     }
46 
47     PetscCallCeed(ceed, CeedQFunctionSetContext(qf_rhs, diff_filter_qfctx));
48     PetscCallCeed(ceed, CeedQFunctionAddInput(qf_rhs, "q", num_comp_q, CEED_EVAL_INTERP));
49     PetscCallCeed(ceed, CeedQFunctionAddInput(qf_rhs, "qdata", num_comp_qd, CEED_EVAL_NONE));
50     PetscCallCeed(ceed, CeedQFunctionAddInput(qf_rhs, "x", num_comp_x, CEED_EVAL_INTERP));
51     for (PetscInt i = 0; i < diff_filter->num_filtered_fields; i++) {
52       char field_name[PETSC_MAX_PATH_LEN];
53       PetscCall(PetscSNPrintf(field_name, PETSC_MAX_PATH_LEN, "v%" PetscInt_FMT, i));
54       PetscCallCeed(ceed, CeedQFunctionAddOutput(qf_rhs, field_name, diff_filter->num_field_components[i], CEED_EVAL_INTERP));
55     }
56 
57     PetscCallCeed(ceed, CeedOperatorCreate(ceed, qf_rhs, NULL, NULL, &op_rhs));
58     PetscCallCeed(ceed, CeedOperatorSetField(op_rhs, "q", ceed_data->elem_restr_q, ceed_data->basis_q, CEED_VECTOR_ACTIVE));
59     PetscCallCeed(ceed, CeedOperatorSetField(op_rhs, "qdata", ceed_data->elem_restr_qd_i, CEED_BASIS_NONE, ceed_data->q_data));
60     PetscCallCeed(ceed, CeedOperatorSetField(op_rhs, "x", ceed_data->elem_restr_x, ceed_data->basis_x, ceed_data->x_coord));
61     for (PetscInt dm_field = 0; dm_field < diff_filter->num_filtered_fields; dm_field++) {
62       char                field_name[PETSC_MAX_PATH_LEN];
63       CeedElemRestriction elem_restr_filter;
64       CeedBasis           basis_filter;
65       DMLabel             domain_label = NULL;
66       PetscInt            label_value = 0, height = 0;
67       PetscCall(DMPlexCeedElemRestrictionCreate(ceed, dm_filter, domain_label, label_value, height, dm_field, &elem_restr_filter));
68       PetscCall(CreateBasisFromPlex(ceed, dm_filter, domain_label, label_value, height, dm_field, &basis_filter));
69 
70       PetscCall(PetscSNPrintf(field_name, PETSC_MAX_PATH_LEN, "v%" PetscInt_FMT, dm_field));
71       PetscCallCeed(ceed, CeedOperatorSetField(op_rhs, field_name, elem_restr_filter, basis_filter, CEED_VECTOR_ACTIVE));
72     }
73 
74     PetscCall(OperatorApplyContextCreate(user->dm, dm_filter, ceed, op_rhs, NULL, NULL, user->Q_loc, NULL, &diff_filter->op_rhs_ctx));
75 
76     PetscCallCeed(ceed, CeedQFunctionDestroy(&qf_rhs));
77     PetscCallCeed(ceed, CeedOperatorDestroy(&op_rhs));
78   }
79 
80   {  // Setup LHS Operator and KSP for the differential filtering solve
81     CeedOperator         op_lhs;
82     OperatorApplyContext mat_ctx;
83     Mat                  mat_lhs;
84     CeedInt              num_comp_qd;
85     PetscInt             dim, num_comp_grid_aniso;
86     CeedElemRestriction  elem_restr_grid_aniso;
87     CeedVector           grid_aniso_ceed;
88 
89     PetscCall(DMGetDimension(user->dm, &dim));
90     PetscCallCeed(ceed, CeedElemRestrictionGetNumComponents(ceed_data->elem_restr_qd_i, &num_comp_qd));
91 
92     // -- Get Grid anisotropy tensor
93     PetscCall(GridAnisotropyTensorCalculateCollocatedVector(ceed, user, ceed_data, &elem_restr_grid_aniso, &grid_aniso_ceed, &num_comp_grid_aniso));
94 
95     PetscCallCeed(ceed, CeedCompositeOperatorCreate(ceed, &op_lhs));
96     for (PetscInt i = 0; i < diff_filter->num_filtered_fields; i++) {
97       CeedQFunction       qf_lhs;
98       PetscInt            num_comp_filter = diff_filter->num_field_components[i];
99       CeedOperator        op_lhs_sub;
100       CeedElemRestriction elem_restr_filter;
101       CeedBasis           basis_filter;
102 
103       switch (num_comp_filter) {
104         case 1:
105           PetscCallCeed(ceed, CeedQFunctionCreateInterior(ceed, 1, DifferentialFilter_LHS_1, DifferentialFilter_LHS_1_loc, &qf_lhs));
106           break;
107         case 5:
108           PetscCallCeed(ceed, CeedQFunctionCreateInterior(ceed, 1, DifferentialFilter_LHS_5, DifferentialFilter_LHS_5_loc, &qf_lhs));
109           break;
110         case 6:
111           PetscCallCeed(ceed, CeedQFunctionCreateInterior(ceed, 1, DifferentialFilter_LHS_6, DifferentialFilter_LHS_6_loc, &qf_lhs));
112           break;
113         case 11:
114           PetscCallCeed(ceed, CeedQFunctionCreateInterior(ceed, 1, DifferentialFilter_LHS_11, DifferentialFilter_LHS_11_loc, &qf_lhs));
115           break;
116         default:
117           SETERRQ(PetscObjectComm((PetscObject)user->dm), PETSC_ERR_SUP, "Differential filtering not available for (%" PetscInt_FMT ") components",
118                   num_comp_filter);
119       }
120 
121       PetscCallCeed(ceed, CeedQFunctionSetContext(qf_lhs, diff_filter_qfctx));
122       PetscCallCeed(ceed, CeedQFunctionAddInput(qf_lhs, "q", num_comp_filter, CEED_EVAL_INTERP));
123       PetscCallCeed(ceed, CeedQFunctionAddInput(qf_lhs, "Grad_q", num_comp_filter * dim, CEED_EVAL_GRAD));
124       PetscCallCeed(ceed, CeedQFunctionAddInput(qf_lhs, "anisotropy tensor", num_comp_grid_aniso, CEED_EVAL_NONE));
125       PetscCallCeed(ceed, CeedQFunctionAddInput(qf_lhs, "x", num_comp_x, CEED_EVAL_INTERP));
126       PetscCallCeed(ceed, CeedQFunctionAddInput(qf_lhs, "qdata", num_comp_qd, CEED_EVAL_NONE));
127       PetscCallCeed(ceed, CeedQFunctionAddOutput(qf_lhs, "v", num_comp_filter, CEED_EVAL_INTERP));
128       PetscCallCeed(ceed, CeedQFunctionAddOutput(qf_lhs, "Grad_v", num_comp_filter * dim, CEED_EVAL_GRAD));
129 
130       {
131         CeedOperatorField op_field;
132         char              field_name[PETSC_MAX_PATH_LEN];
133         PetscCall(PetscSNPrintf(field_name, PETSC_MAX_PATH_LEN, "v%" PetscInt_FMT, i));
134         PetscCallCeed(ceed, CeedOperatorGetFieldByName(diff_filter->op_rhs_ctx->op, field_name, &op_field));
135         PetscCallCeed(ceed, CeedOperatorFieldGetElemRestriction(op_field, &elem_restr_filter));
136         PetscCallCeed(ceed, CeedOperatorFieldGetBasis(op_field, &basis_filter));
137       }
138 
139       PetscCallCeed(ceed, CeedOperatorCreate(ceed, qf_lhs, NULL, NULL, &op_lhs_sub));
140       PetscCallCeed(ceed, CeedOperatorSetField(op_lhs_sub, "q", elem_restr_filter, basis_filter, CEED_VECTOR_ACTIVE));
141       PetscCallCeed(ceed, CeedOperatorSetField(op_lhs_sub, "Grad_q", elem_restr_filter, basis_filter, CEED_VECTOR_ACTIVE));
142       PetscCallCeed(ceed, CeedOperatorSetField(op_lhs_sub, "anisotropy tensor", elem_restr_grid_aniso, CEED_BASIS_NONE, grid_aniso_ceed));
143       PetscCallCeed(ceed, CeedOperatorSetField(op_lhs_sub, "x", ceed_data->elem_restr_x, ceed_data->basis_x, ceed_data->x_coord));
144       PetscCallCeed(ceed, CeedOperatorSetField(op_lhs_sub, "qdata", ceed_data->elem_restr_qd_i, CEED_BASIS_NONE, ceed_data->q_data));
145       PetscCallCeed(ceed, CeedOperatorSetField(op_lhs_sub, "v", elem_restr_filter, basis_filter, CEED_VECTOR_ACTIVE));
146       PetscCallCeed(ceed, CeedOperatorSetField(op_lhs_sub, "Grad_v", elem_restr_filter, basis_filter, CEED_VECTOR_ACTIVE));
147 
148       PetscCallCeed(ceed, CeedCompositeOperatorAddSub(op_lhs, op_lhs_sub));
149       PetscCallCeed(ceed, CeedQFunctionDestroy(&qf_lhs));
150       PetscCallCeed(ceed, CeedOperatorDestroy(&op_lhs_sub));
151     }
152     PetscCall(OperatorApplyContextCreate(dm_filter, dm_filter, ceed, op_lhs, NULL, NULL, NULL, NULL, &mat_ctx));
153     PetscCall(CreateMatShell_Ceed(mat_ctx, &mat_lhs));
154 
155     PetscCall(KSPCreate(PetscObjectComm((PetscObject)dm_filter), &diff_filter->ksp));
156     PetscCall(KSPSetOptionsPrefix(diff_filter->ksp, "diff_filter_"));
157     {
158       PC pc;
159       PetscCall(KSPGetPC(diff_filter->ksp, &pc));
160       PetscCall(PCSetType(pc, PCJACOBI));
161       PetscCall(PCJacobiSetType(pc, PC_JACOBI_DIAGONAL));
162       PetscCall(KSPSetType(diff_filter->ksp, KSPCG));
163       PetscCall(KSPSetNormType(diff_filter->ksp, KSP_NORM_NATURAL));
164       PetscCall(KSPSetTolerances(diff_filter->ksp, 1e-10, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT));
165     }
166     PetscCall(KSPSetOperators(diff_filter->ksp, mat_lhs, mat_lhs));
167     PetscCall(KSPSetFromOptions(diff_filter->ksp));
168 
169     PetscCall(MatDestroy(&mat_lhs));
170     PetscCallCeed(ceed, CeedOperatorDestroy(&op_lhs));
171   }
172   PetscFunctionReturn(PETSC_SUCCESS);
173 }
174 
175 // @brief Setup DM, operators, contexts, etc. for performing differential filtering
176 PetscErrorCode DifferentialFilterSetup(Ceed ceed, User user, CeedData ceed_data, ProblemData *problem) {
177   MPI_Comm                  comm = user->comm;
178   NewtonianIdealGasContext  gas;
179   DifferentialFilterContext diff_filter_ctx;
180   CeedQFunctionContext      diff_filter_qfctx;
181 
182   PetscFunctionBeginUser;
183   PetscCall(PetscNew(&user->diff_filter));
184   DiffFilterData diff_filter = user->diff_filter;
185   PetscCall(PetscOptionsGetBool(NULL, NULL, "-diff_filter_mms", &diff_filter->do_mms_test, NULL));
186 
187   {  // Create DM for filtered quantities
188     PetscSection section;
189 
190     PetscCall(DMClone(user->dm, &diff_filter->dm_filter));
191     PetscCall(PetscObjectSetName((PetscObject)diff_filter->dm_filter, "Differential Filtering"));
192 
193     diff_filter->num_filtered_fields = diff_filter->do_mms_test ? 1 : 2;
194     PetscCall(PetscMalloc1(diff_filter->num_filtered_fields, &diff_filter->num_field_components));
195 
196     if (diff_filter->do_mms_test) {
197       PetscInt field_components;
198       diff_filter->num_field_components[0] = field_components = 1;
199       PetscCall(DMSetupByOrder_FEM(PETSC_TRUE, PETSC_TRUE, user->app_ctx->degree, 1, user->app_ctx->q_extra, diff_filter->num_filtered_fields,
200                                    &field_components, diff_filter->dm_filter));
201 
202       PetscCall(DMGetLocalSection(diff_filter->dm_filter, &section));
203       PetscCall(PetscSectionSetFieldName(section, 0, ""));
204       PetscCall(PetscSectionSetComponentName(section, 0, 0, "FilteredPhi"));
205     } else {
206       PetscInt field_components[2];
207       diff_filter->num_field_components[0] = field_components[0] = DIFF_FILTER_STATE_NUM;
208       diff_filter->num_field_components[1] = field_components[1] = DIFF_FILTER_VELOCITY_SQUARED_NUM;
209       PetscCall(DMSetupByOrder_FEM(PETSC_TRUE, PETSC_TRUE, user->app_ctx->degree, 1, user->app_ctx->q_extra, diff_filter->num_filtered_fields,
210                                    field_components, diff_filter->dm_filter));
211 
212       diff_filter->field_prim_state = 0;
213       diff_filter->field_velo_prod  = 1;
214       PetscCall(DMGetLocalSection(diff_filter->dm_filter, &section));
215       PetscCall(PetscSectionSetFieldName(section, diff_filter->field_prim_state, "Filtered Primitive State Variables"));
216       PetscCall(PetscSectionSetComponentName(section, 0, DIFF_FILTER_PRESSURE, "FilteredPressure"));
217       PetscCall(PetscSectionSetComponentName(section, 0, DIFF_FILTER_VELOCITY_X, "FilteredVelocityX"));
218       PetscCall(PetscSectionSetComponentName(section, 0, DIFF_FILTER_VELOCITY_Y, "FilteredVelocityY"));
219       PetscCall(PetscSectionSetComponentName(section, 0, DIFF_FILTER_VELOCITY_Z, "FilteredVelocityZ"));
220       PetscCall(PetscSectionSetComponentName(section, 0, DIFF_FILTER_TEMPERATURE, "FilteredTemperature"));
221       PetscCall(PetscSectionSetFieldName(section, diff_filter->field_velo_prod, "Filtered Velocity Products"));
222       PetscCall(PetscSectionSetComponentName(section, 1, DIFF_FILTER_VELOCITY_SQUARED_XX, "FilteredVelocitySquaredXX"));
223       PetscCall(PetscSectionSetComponentName(section, 1, DIFF_FILTER_VELOCITY_SQUARED_YY, "FilteredVelocitySquaredYY"));
224       PetscCall(PetscSectionSetComponentName(section, 1, DIFF_FILTER_VELOCITY_SQUARED_ZZ, "FilteredVelocitySquaredZZ"));
225       PetscCall(PetscSectionSetComponentName(section, 1, DIFF_FILTER_VELOCITY_SQUARED_YZ, "FilteredVelocitySquaredYZ"));
226       PetscCall(PetscSectionSetComponentName(section, 1, DIFF_FILTER_VELOCITY_SQUARED_XZ, "FilteredVelocitySquaredXZ"));
227       PetscCall(PetscSectionSetComponentName(section, 1, DIFF_FILTER_VELOCITY_SQUARED_XY, "FilteredVelocitySquaredXY"));
228     }
229   }
230 
231   PetscCall(PetscNew(&diff_filter_ctx));
232   diff_filter_ctx->grid_based_width = false;
233   for (int i = 0; i < 3; i++) diff_filter_ctx->width_scaling[i] = 1;
234   diff_filter_ctx->kernel_scaling   = 0.1;
235   diff_filter_ctx->damping_function = DIFF_FILTER_DAMP_NONE;
236   diff_filter_ctx->friction_length  = 0;
237   diff_filter_ctx->damping_constant = 25;
238 
239   PetscOptionsBegin(comm, NULL, "Differential Filtering Options", NULL);
240   PetscInt narray = 3;
241   PetscCall(PetscOptionsBool("-diff_filter_grid_based_width", "Use filter width based on the grid size", NULL, diff_filter_ctx->grid_based_width,
242                              (PetscBool *)&diff_filter_ctx->grid_based_width, NULL));
243   PetscCall(PetscOptionsRealArray("-diff_filter_width_scaling", "Anisotropic scaling of filter width tensor", NULL, diff_filter_ctx->width_scaling,
244                                   &narray, NULL));
245   PetscCall(PetscOptionsReal("-diff_filter_kernel_scaling", "Scaling to make differential kernel size \"equivalent\" to other filter kernels", NULL,
246                              diff_filter_ctx->kernel_scaling, &diff_filter_ctx->kernel_scaling, NULL));
247   PetscCall(PetscOptionsEnum("-diff_filter_wall_damping_function", "Damping function to use at the wall", NULL, DifferentialFilterDampingFunctions,
248                              (PetscEnum)(diff_filter_ctx->damping_function), (PetscEnum *)&diff_filter_ctx->damping_function, NULL));
249   PetscCall(PetscOptionsReal("-diff_filter_wall_damping_constant", "Contant for the wall-damping function", NULL, diff_filter_ctx->damping_constant,
250                              &diff_filter_ctx->damping_constant, NULL));
251   PetscCall(PetscOptionsReal("-diff_filter_friction_length", "Friction length associated with the flow, \\delta_\\nu. For wall-damping functions",
252                              NULL, diff_filter_ctx->friction_length, &diff_filter_ctx->friction_length, NULL));
253   PetscOptionsEnd();
254 
255   Units units = user->units;
256   for (int i = 0; i < 3; i++) diff_filter_ctx->width_scaling[i] *= units->meter;
257   diff_filter_ctx->kernel_scaling *= units->meter;
258   diff_filter_ctx->friction_length *= units->meter;
259 
260   // -- Create QFContext
261   PetscCallCeed(ceed, CeedQFunctionContextGetDataRead(problem->apply_vol_ifunction.qfunction_context, CEED_MEM_HOST, &gas));
262   diff_filter_ctx->gas = *gas;
263   PetscCallCeed(ceed, CeedQFunctionContextRestoreDataRead(problem->apply_vol_ifunction.qfunction_context, &gas));
264 
265   PetscCallCeed(ceed, CeedQFunctionContextCreate(ceed, &diff_filter_qfctx));
266   PetscCallCeed(ceed, CeedQFunctionContextSetData(diff_filter_qfctx, CEED_MEM_HOST, CEED_USE_POINTER, sizeof(*diff_filter_ctx), diff_filter_ctx));
267   PetscCallCeed(ceed, CeedQFunctionContextSetDataDestroy(diff_filter_qfctx, CEED_MEM_HOST, FreeContextPetsc));
268 
269   // -- Setup Operators
270   PetscCall(DifferentialFilterCreateOperators(ceed, user, ceed_data, diff_filter_qfctx));
271 
272   PetscCallCeed(ceed, CeedQFunctionContextDestroy(&diff_filter_qfctx));
273   PetscFunctionReturn(PETSC_SUCCESS);
274 }
275 
276 // @brief Apply differential filter to the solution given by Q
277 PetscErrorCode DifferentialFilterApply(User user, const PetscReal solution_time, const Vec Q, Vec Filtered_Solution) {
278   DiffFilterData diff_filter = user->diff_filter;
279 
280   PetscFunctionBeginUser;
281   PetscCall(PetscLogEventBegin(FLUIDS_DifferentialFilter, Q, Filtered_Solution, 0, 0));
282   PetscCall(UpdateBoundaryValues(user, diff_filter->op_rhs_ctx->X_loc, solution_time));
283   ApplyCeedOperatorGlobalToGlobal(Q, Filtered_Solution, diff_filter->op_rhs_ctx);
284   PetscCall(VecViewFromOptions(Filtered_Solution, NULL, "-diff_filter_rhs_view"));
285 
286   PetscCall(KSPSolve(diff_filter->ksp, Filtered_Solution, Filtered_Solution));
287   PetscCall(PetscLogEventEnd(FLUIDS_DifferentialFilter, Q, Filtered_Solution, 0, 0));
288   PetscFunctionReturn(PETSC_SUCCESS);
289 }
290 
291 // @brief TSMonitor for just applying differential filtering to the simulation
292 // This runs every time step and is primarily for testing purposes
293 PetscErrorCode TSMonitor_DifferentialFilter(TS ts, PetscInt steps, PetscReal solution_time, Vec Q, void *ctx) {
294   User           user        = (User)ctx;
295   DiffFilterData diff_filter = user->diff_filter;
296   Vec            Filtered_Field;
297 
298   PetscFunctionBeginUser;
299   PetscCall(DMGetGlobalVector(diff_filter->dm_filter, &Filtered_Field));
300 
301   PetscCall(DifferentialFilterApply(user, solution_time, Q, Filtered_Field));
302   PetscCall(VecViewFromOptions(Filtered_Field, NULL, "-diff_filter_view"));
303   if (user->app_ctx->test_type == TESTTYPE_DIFF_FILTER) PetscCall(RegressionTest(user->app_ctx, Filtered_Field));
304 
305   PetscCall(DMRestoreGlobalVector(diff_filter->dm_filter, &Filtered_Field));
306   PetscFunctionReturn(PETSC_SUCCESS);
307 }
308 
309 PetscErrorCode DifferentialFilterDataDestroy(DiffFilterData diff_filter) {
310   PetscFunctionBeginUser;
311   if (!diff_filter) PetscFunctionReturn(PETSC_SUCCESS);
312 
313   PetscCall(OperatorApplyContextDestroy(diff_filter->op_rhs_ctx));
314   PetscCall(DMDestroy(&diff_filter->dm_filter));
315   PetscCall(KSPDestroy(&diff_filter->ksp));
316 
317   PetscCall(PetscFree(diff_filter->num_field_components));
318   PetscCall(PetscFree(diff_filter));
319   PetscFunctionReturn(PETSC_SUCCESS);
320 }
321 
322 PetscErrorCode DifferentialFilterMmsICSetup(ProblemData *problem) {
323   PetscFunctionBeginUser;
324   problem->ics.qfunction     = DifferentialFilter_MMS_IC;
325   problem->ics.qfunction_loc = DifferentialFilter_MMS_IC_loc;
326   PetscFunctionReturn(PETSC_SUCCESS);
327 }
328