xref: /honee/src/setupts.c (revision 2eb7bf1f053ac0d88882dea063c972b858799d42)
1 // Copyright (c) 2017-2022, 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 
8 /// @file
9 /// Time-stepping functions for Navier-Stokes example using PETSc
10 
11 #include <ceed.h>
12 #include <petscdmplex.h>
13 #include <petscts.h>
14 
15 #include "../navierstokes.h"
16 #include "../qfunctions/newtonian_state.h"
17 
18 // Compute mass matrix for explicit scheme
19 PetscErrorCode ComputeLumpedMassMatrix(Ceed ceed, DM dm, CeedData ceed_data, Vec M) {
20   Vec           M_loc;
21   CeedQFunction qf_mass;
22   CeedOperator  op_mass;
23   CeedVector    m_ceed, ones_vec;
24   CeedInt       num_comp_q, q_data_size;
25   PetscFunctionBeginUser;
26 
27   // CEED Restriction
28   CeedElemRestrictionGetNumComponents(ceed_data->elem_restr_q, &num_comp_q);
29   CeedElemRestrictionGetNumComponents(ceed_data->elem_restr_qd_i, &q_data_size);
30   CeedElemRestrictionCreateVector(ceed_data->elem_restr_q, &m_ceed, NULL);
31   CeedElemRestrictionCreateVector(ceed_data->elem_restr_q, &ones_vec, NULL);
32   CeedVectorSetValue(ones_vec, 1.0);
33 
34   // CEED QFunction
35   PetscCall(CreateMassQFunction(ceed, num_comp_q, q_data_size, &qf_mass));
36 
37   // CEED Operator
38   CeedOperatorCreate(ceed, qf_mass, NULL, NULL, &op_mass);
39   CeedOperatorSetField(op_mass, "u", ceed_data->elem_restr_q, ceed_data->basis_q, CEED_VECTOR_ACTIVE);
40   CeedOperatorSetField(op_mass, "qdata", ceed_data->elem_restr_qd_i, CEED_BASIS_COLLOCATED, ceed_data->q_data);
41   CeedOperatorSetField(op_mass, "v", ceed_data->elem_restr_q, ceed_data->basis_q, CEED_VECTOR_ACTIVE);
42 
43   // Place PETSc vector in CEED vector
44   PetscMemType m_mem_type;
45   PetscCall(DMGetLocalVector(dm, &M_loc));
46   PetscCall(VecP2C(M_loc, &m_mem_type, m_ceed));
47 
48   // Apply CEED Operator
49   CeedOperatorApply(op_mass, ones_vec, m_ceed, CEED_REQUEST_IMMEDIATE);
50 
51   // Restore vectors
52   PetscCall(VecC2P(m_ceed, m_mem_type, M_loc));
53 
54   // Local-to-Global
55   PetscCall(VecZeroEntries(M));
56   PetscCall(DMLocalToGlobal(dm, M_loc, ADD_VALUES, M));
57   PetscCall(DMRestoreLocalVector(dm, &M_loc));
58 
59   // Invert diagonally lumped mass vector for RHS function
60   PetscCall(VecReciprocal(M));
61 
62   // Cleanup
63   CeedVectorDestroy(&ones_vec);
64   CeedVectorDestroy(&m_ceed);
65   CeedQFunctionDestroy(&qf_mass);
66   CeedOperatorDestroy(&op_mass);
67 
68   PetscFunctionReturn(0);
69 }
70 
71 // Insert Boundary values if it's a new time
72 PetscErrorCode UpdateBoundaryValues(User user, Vec Q_loc, PetscReal t) {
73   PetscFunctionBeginUser;
74   if (user->time_bc_set != t) {
75     PetscCall(DMPlexInsertBoundaryValues(user->dm, PETSC_TRUE, Q_loc, t, NULL, NULL, NULL));
76     user->time_bc_set = t;
77   }
78   PetscFunctionReturn(0);
79 }
80 
81 // @brief Update the context label value to new value if necessary.
82 // @note This only supports labels with scalar label values (ie. not arrays)
83 PetscErrorCode UpdateContextLabel(MPI_Comm comm, PetscScalar update_value, CeedOperator op, CeedContextFieldLabel label) {
84   PetscScalar label_value;
85 
86   PetscFunctionBeginUser;
87   PetscCheck(label, comm, PETSC_ERR_ARG_BADPTR, "Label should be non-NULL");
88 
89   {
90     size_t             num_elements;
91     const PetscScalar *label_values;
92     CeedOperatorGetContextDoubleRead(op, label, &num_elements, &label_values);
93     PetscCheck(num_elements == 1, comm, PETSC_ERR_SUP, "%s does not support labels with more than 1 value. Label has %zu values", __func__,
94                num_elements);
95     label_value = *label_values;
96     CeedOperatorRestoreContextDoubleRead(op, label, &label_values);
97   }
98 
99   if (label_value != update_value) {
100     CeedOperatorSetContextDouble(op, label, &update_value);
101   }
102   PetscFunctionReturn(0);
103 }
104 
105 // RHS (Explicit time-stepper) function setup
106 //   This is the RHS of the ODE, given as u_t = G(t,u)
107 //   This function takes in a state vector Q and writes into G
108 PetscErrorCode RHS_NS(TS ts, PetscReal t, Vec Q, Vec G, void *user_data) {
109   User         user = *(User *)user_data;
110   MPI_Comm     comm = PetscObjectComm((PetscObject)ts);
111   PetscScalar  dt;
112   Vec          Q_loc = user->Q_loc, G_loc;
113   PetscMemType q_mem_type, g_mem_type;
114   PetscFunctionBeginUser;
115 
116   // Get local vector
117   PetscCall(DMGetLocalVector(user->dm, &G_loc));
118 
119   // Update time dependent data
120   PetscCall(UpdateBoundaryValues(user, Q_loc, t));
121   if (user->phys->solution_time_label) PetscCall(UpdateContextLabel(comm, t, user->op_rhs, user->phys->solution_time_label));
122   PetscCall(TSGetTimeStep(ts, &dt));
123   if (user->phys->timestep_size_label) PetscCall(UpdateContextLabel(comm, dt, user->op_rhs, user->phys->timestep_size_label));
124 
125   // Global-to-local
126   PetscCall(DMGlobalToLocal(user->dm, Q, INSERT_VALUES, Q_loc));
127 
128   // Place PETSc vectors in CEED vectors
129   PetscCall(VecReadP2C(Q_loc, &q_mem_type, user->q_ceed));
130   PetscCall(VecP2C(G_loc, &g_mem_type, user->g_ceed));
131 
132   // Apply CEED operator
133   CeedOperatorApply(user->op_rhs, user->q_ceed, user->g_ceed, CEED_REQUEST_IMMEDIATE);
134 
135   // Restore vectors
136   PetscCall(VecReadC2P(user->q_ceed, q_mem_type, Q_loc));
137   PetscCall(VecC2P(user->g_ceed, g_mem_type, G_loc));
138 
139   // Local-to-Global
140   PetscCall(VecZeroEntries(G));
141   PetscCall(DMLocalToGlobal(user->dm, G_loc, ADD_VALUES, G));
142 
143   // Inverse of the lumped mass matrix (M is Minv)
144   PetscCall(VecPointwiseMult(G, G, user->M));
145 
146   // Restore vectors
147   PetscCall(DMRestoreLocalVector(user->dm, &G_loc));
148 
149   PetscFunctionReturn(0);
150 }
151 
152 // Surface forces function setup
153 static PetscErrorCode Surface_Forces_NS(DM dm, Vec G_loc, PetscInt num_walls, const PetscInt walls[], PetscScalar *reaction_force) {
154   DMLabel            face_label;
155   const PetscScalar *g;
156   PetscInt           dof, dim = 3;
157   MPI_Comm           comm;
158   PetscSection       s;
159 
160   PetscFunctionBeginUser;
161   PetscCall(PetscArrayzero(reaction_force, num_walls * dim));
162   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
163   PetscCall(DMGetLabel(dm, "Face Sets", &face_label));
164   PetscCall(VecGetArrayRead(G_loc, &g));
165   for (PetscInt w = 0; w < num_walls; w++) {
166     const PetscInt wall = walls[w];
167     IS             wall_is;
168     PetscCall(DMGetLocalSection(dm, &s));
169     PetscCall(DMLabelGetStratumIS(face_label, wall, &wall_is));
170     if (wall_is) {  // There exist such points on this process
171       PetscInt        num_points;
172       PetscInt        num_comp = 0;
173       const PetscInt *points;
174       PetscCall(PetscSectionGetFieldComponents(s, 0, &num_comp));
175       PetscCall(ISGetSize(wall_is, &num_points));
176       PetscCall(ISGetIndices(wall_is, &points));
177       for (PetscInt i = 0; i < num_points; i++) {
178         const PetscInt           p = points[i];
179         const StateConservative *r;
180         PetscCall(DMPlexPointLocalRead(dm, p, g, &r));
181         PetscCall(PetscSectionGetDof(s, p, &dof));
182         for (PetscInt node = 0; node < dof / num_comp; node++) {
183           for (PetscInt j = 0; j < 3; j++) {
184             reaction_force[w * dim + j] -= r[node].momentum[j];
185           }
186         }
187       }
188       PetscCall(ISRestoreIndices(wall_is, &points));
189     }
190     PetscCall(ISDestroy(&wall_is));
191   }
192   PetscCallMPI(MPI_Allreduce(MPI_IN_PLACE, reaction_force, dim * num_walls, MPIU_SCALAR, MPI_SUM, comm));
193   //  Restore Vectors
194   PetscCall(VecRestoreArrayRead(G_loc, &g));
195 
196   PetscFunctionReturn(0);
197 }
198 
199 // Implicit time-stepper function setup
200 PetscErrorCode IFunction_NS(TS ts, PetscReal t, Vec Q, Vec Q_dot, Vec G, void *user_data) {
201   User         user = *(User *)user_data;
202   MPI_Comm     comm = PetscObjectComm((PetscObject)ts);
203   PetscScalar  dt;
204   Vec          Q_loc = user->Q_loc, Q_dot_loc = user->Q_dot_loc, G_loc;
205   PetscMemType q_mem_type, q_dot_mem_type, g_mem_type;
206   PetscFunctionBeginUser;
207 
208   // Get local vectors
209   PetscCall(DMGetNamedLocalVector(user->dm, "ResidualLocal", &G_loc));
210 
211   // Update time dependent data
212   PetscCall(UpdateBoundaryValues(user, Q_loc, t));
213   if (user->phys->solution_time_label) PetscCall(UpdateContextLabel(comm, t, user->op_ifunction, user->phys->solution_time_label));
214   PetscCall(TSGetTimeStep(ts, &dt));
215   if (user->phys->timestep_size_label) PetscCall(UpdateContextLabel(comm, dt, user->op_ifunction, user->phys->timestep_size_label));
216 
217   // Global-to-local
218   PetscCall(DMGlobalToLocalBegin(user->dm, Q, INSERT_VALUES, Q_loc));
219   PetscCall(DMGlobalToLocalBegin(user->dm, Q_dot, INSERT_VALUES, Q_dot_loc));
220   PetscCall(DMGlobalToLocalEnd(user->dm, Q, INSERT_VALUES, Q_loc));
221   PetscCall(DMGlobalToLocalEnd(user->dm, Q_dot, INSERT_VALUES, Q_dot_loc));
222 
223   // Place PETSc vectors in CEED vectors
224   PetscCall(VecReadP2C(Q_loc, &q_mem_type, user->q_ceed));
225   PetscCall(VecReadP2C(Q_dot_loc, &q_dot_mem_type, user->q_dot_ceed));
226   PetscCall(VecP2C(G_loc, &g_mem_type, user->g_ceed));
227 
228   // Apply CEED operator
229   CeedOperatorApply(user->op_ifunction, user->q_ceed, user->g_ceed, CEED_REQUEST_IMMEDIATE);
230 
231   // Restore vectors
232   PetscCall(VecReadC2P(user->q_ceed, q_mem_type, Q_loc));
233   PetscCall(VecReadC2P(user->q_dot_ceed, q_dot_mem_type, Q_dot_loc));
234   PetscCall(VecC2P(user->g_ceed, g_mem_type, G_loc));
235 
236   if (user->app_ctx->sgs_model_type == SGS_MODEL_DATA_DRIVEN) {
237     PetscCall(SGS_DD_ModelApplyIFunction(user, Q_loc, G_loc));
238   }
239 
240   // Local-to-Global
241   PetscCall(VecZeroEntries(G));
242   PetscCall(DMLocalToGlobal(user->dm, G_loc, ADD_VALUES, G));
243 
244   // Restore vectors
245   PetscCall(DMRestoreNamedLocalVector(user->dm, "ResidualLocal", &G_loc));
246 
247   PetscFunctionReturn(0);
248 }
249 
250 static PetscErrorCode FormPreallocation(User user, PetscBool pbdiagonal, Mat J, CeedVector *coo_values) {
251   PetscCount ncoo;
252   PetscInt  *rows, *cols;
253 
254   PetscFunctionBeginUser;
255   if (pbdiagonal) {
256     CeedSize l_size;
257     CeedOperatorGetActiveVectorLengths(user->op_ijacobian, &l_size, NULL);
258     ncoo = l_size * 5;
259     rows = malloc(ncoo * sizeof(rows[0]));
260     cols = malloc(ncoo * sizeof(cols[0]));
261     for (PetscCount n = 0; n < l_size / 5; n++) {
262       for (PetscInt i = 0; i < 5; i++) {
263         for (PetscInt j = 0; j < 5; j++) {
264           rows[(n * 5 + i) * 5 + j] = n * 5 + i;
265           cols[(n * 5 + i) * 5 + j] = n * 5 + j;
266         }
267       }
268     }
269   } else {
270     PetscCall(CeedOperatorLinearAssembleSymbolic(user->op_ijacobian, &ncoo, &rows, &cols));
271   }
272   PetscCall(MatSetPreallocationCOOLocal(J, ncoo, rows, cols));
273   free(rows);
274   free(cols);
275   CeedVectorCreate(user->ceed, ncoo, coo_values);
276   PetscFunctionReturn(0);
277 }
278 
279 static PetscErrorCode FormSetValues(User user, PetscBool pbdiagonal, Mat J, CeedVector coo_values) {
280   CeedMemType        mem_type = CEED_MEM_HOST;
281   const PetscScalar *values;
282   MatType            mat_type;
283 
284   PetscFunctionBeginUser;
285   PetscCall(MatGetType(J, &mat_type));
286   if (strstr(mat_type, "kokkos") || strstr(mat_type, "cusparse")) mem_type = CEED_MEM_DEVICE;
287   if (user->app_ctx->pmat_pbdiagonal) {
288     CeedOperatorLinearAssemblePointBlockDiagonal(user->op_ijacobian, coo_values, CEED_REQUEST_IMMEDIATE);
289   } else {
290     CeedOperatorLinearAssemble(user->op_ijacobian, coo_values);
291   }
292   CeedVectorGetArrayRead(coo_values, mem_type, &values);
293   PetscCall(MatSetValuesCOO(J, values, INSERT_VALUES));
294   CeedVectorRestoreArrayRead(coo_values, &values);
295   PetscFunctionReturn(0);
296 }
297 
298 PetscErrorCode FormIJacobian_NS(TS ts, PetscReal t, Vec Q, Vec Q_dot, PetscReal shift, Mat J, Mat J_pre, void *user_data) {
299   User      user = *(User *)user_data;
300   PetscBool J_is_shell, J_is_mffd, J_pre_is_shell;
301   PetscFunctionBeginUser;
302   if (user->phys->ijacobian_time_shift_label) CeedOperatorSetContextDouble(user->op_ijacobian, user->phys->ijacobian_time_shift_label, &shift);
303   PetscCall(PetscObjectTypeCompare((PetscObject)J, MATMFFD, &J_is_mffd));
304   PetscCall(PetscObjectTypeCompare((PetscObject)J, MATSHELL, &J_is_shell));
305   PetscCall(PetscObjectTypeCompare((PetscObject)J_pre, MATSHELL, &J_pre_is_shell));
306   if (!user->matrices_set_up) {
307     if (J_is_shell) {
308       OperatorApplyContext op_ijacobian_ctx;
309       OperatorApplyContextCreate(user->dm, user->dm, user->ceed, user->op_ijacobian, user->q_ceed, user->g_ceed, user->Q_dot_loc, NULL,
310                                  &op_ijacobian_ctx);
311       PetscCall(MatShellSetContext(J, op_ijacobian_ctx));
312       PetscCall(MatShellSetContextDestroy(J, (PetscErrorCode(*)(void *))OperatorApplyContextDestroy));
313       PetscCall(MatShellSetOperation(J, MATOP_MULT, (void (*)(void))MatMult_Ceed));
314       PetscCall(MatShellSetOperation(J, MATOP_GET_DIAGONAL, (void (*)(void))MatGetDiag_Ceed));
315       PetscCall(MatSetUp(J));
316     }
317     if (!J_pre_is_shell) {
318       PetscCall(FormPreallocation(user, user->app_ctx->pmat_pbdiagonal, J_pre, &user->coo_values_pmat));
319     }
320     if (J != J_pre && !J_is_shell && !J_is_mffd) {
321       PetscCall(FormPreallocation(user, PETSC_FALSE, J, &user->coo_values_amat));
322     }
323     user->matrices_set_up = true;
324   }
325   if (!J_pre_is_shell) {
326     PetscCall(FormSetValues(user, user->app_ctx->pmat_pbdiagonal, J_pre, user->coo_values_pmat));
327   }
328   if (user->coo_values_amat) {
329     PetscCall(FormSetValues(user, PETSC_FALSE, J, user->coo_values_amat));
330   } else if (J_is_mffd) {
331     PetscCall(MatAssemblyBegin(J, MAT_FINAL_ASSEMBLY));
332     PetscCall(MatAssemblyEnd(J, MAT_FINAL_ASSEMBLY));
333   }
334   PetscFunctionReturn(0);
335 }
336 
337 PetscErrorCode WriteOutput(User user, Vec Q, PetscInt step_no, PetscScalar time) {
338   Vec         Q_loc;
339   char        file_path[PETSC_MAX_PATH_LEN];
340   PetscViewer viewer;
341   PetscFunctionBeginUser;
342 
343   if (user->app_ctx->checkpoint_vtk) {
344     // Set up output
345     PetscCall(DMGetLocalVector(user->dm, &Q_loc));
346     PetscCall(PetscObjectSetName((PetscObject)Q_loc, "StateVec"));
347     PetscCall(VecZeroEntries(Q_loc));
348     PetscCall(DMGlobalToLocal(user->dm, Q, INSERT_VALUES, Q_loc));
349 
350     // Output
351     PetscCall(PetscSNPrintf(file_path, sizeof file_path, "%s/ns-%03" PetscInt_FMT ".vtu", user->app_ctx->output_dir, step_no));
352 
353     PetscCall(PetscViewerVTKOpen(PetscObjectComm((PetscObject)Q), file_path, FILE_MODE_WRITE, &viewer));
354     PetscCall(VecView(Q_loc, viewer));
355     PetscCall(PetscViewerDestroy(&viewer));
356     if (user->dm_viz) {
357       Vec         Q_refined, Q_refined_loc;
358       char        file_path_refined[PETSC_MAX_PATH_LEN];
359       PetscViewer viewer_refined;
360 
361       PetscCall(DMGetGlobalVector(user->dm_viz, &Q_refined));
362       PetscCall(DMGetLocalVector(user->dm_viz, &Q_refined_loc));
363       PetscCall(PetscObjectSetName((PetscObject)Q_refined_loc, "Refined"));
364 
365       PetscCall(MatInterpolate(user->interp_viz, Q, Q_refined));
366       PetscCall(VecZeroEntries(Q_refined_loc));
367       PetscCall(DMGlobalToLocal(user->dm_viz, Q_refined, INSERT_VALUES, Q_refined_loc));
368 
369       PetscCall(
370           PetscSNPrintf(file_path_refined, sizeof file_path_refined, "%s/nsrefined-%03" PetscInt_FMT ".vtu", user->app_ctx->output_dir, step_no));
371 
372       PetscCall(PetscViewerVTKOpen(PetscObjectComm((PetscObject)Q_refined), file_path_refined, FILE_MODE_WRITE, &viewer_refined));
373       PetscCall(VecView(Q_refined_loc, viewer_refined));
374       PetscCall(DMRestoreLocalVector(user->dm_viz, &Q_refined_loc));
375       PetscCall(DMRestoreGlobalVector(user->dm_viz, &Q_refined));
376       PetscCall(PetscViewerDestroy(&viewer_refined));
377     }
378     PetscCall(DMRestoreLocalVector(user->dm, &Q_loc));
379   }
380 
381   // Save data in a binary file for continuation of simulations
382   if (user->app_ctx->add_stepnum2bin) {
383     PetscCall(PetscSNPrintf(file_path, sizeof file_path, "%s/ns-solution-%" PetscInt_FMT ".bin", user->app_ctx->output_dir, step_no));
384   } else {
385     PetscCall(PetscSNPrintf(file_path, sizeof file_path, "%s/ns-solution.bin", user->app_ctx->output_dir));
386   }
387   PetscCall(PetscViewerBinaryOpen(user->comm, file_path, FILE_MODE_WRITE, &viewer));
388 
389   PetscInt token = FLUIDS_FILE_TOKEN;
390   PetscCall(PetscViewerBinaryWrite(viewer, &token, 1, PETSC_INT));
391   PetscCall(PetscViewerBinaryWrite(viewer, &step_no, 1, PETSC_INT));
392   time /= user->units->second;  // Dimensionalize time back
393   PetscCall(PetscViewerBinaryWrite(viewer, &time, 1, PETSC_REAL));
394   PetscCall(VecView(Q, viewer));
395   PetscCall(PetscViewerDestroy(&viewer));
396   PetscFunctionReturn(0);
397 }
398 
399 // CSV Monitor
400 PetscErrorCode TSMonitor_WallForce(TS ts, PetscInt step_no, PetscReal time, Vec Q, void *ctx) {
401   User              user = ctx;
402   Vec               G_loc;
403   PetscInt          num_wall = user->app_ctx->wall_forces.num_wall, dim = 3;
404   const PetscInt   *walls  = user->app_ctx->wall_forces.walls;
405   PetscViewer       viewer = user->app_ctx->wall_forces.viewer;
406   PetscViewerFormat format = user->app_ctx->wall_forces.viewer_format;
407   PetscScalar      *reaction_force;
408   PetscBool         iascii;
409 
410   PetscFunctionBeginUser;
411   if (!viewer) PetscFunctionReturn(0);
412   PetscCall(DMGetNamedLocalVector(user->dm, "ResidualLocal", &G_loc));
413   PetscCall(PetscMalloc1(num_wall * dim, &reaction_force));
414   PetscCall(Surface_Forces_NS(user->dm, G_loc, num_wall, walls, reaction_force));
415   PetscCall(DMRestoreNamedLocalVector(user->dm, "ResidualLocal", &G_loc));
416 
417   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii));
418 
419   if (iascii) {
420     if (format == PETSC_VIEWER_ASCII_CSV && !user->app_ctx->wall_forces.header_written) {
421       PetscCall(PetscViewerASCIIPrintf(viewer, "Step,Time,Wall,ForceX,ForceY,ForceZ\n"));
422       user->app_ctx->wall_forces.header_written = PETSC_TRUE;
423     }
424     for (PetscInt w = 0; w < num_wall; w++) {
425       PetscInt wall = walls[w];
426       if (format == PETSC_VIEWER_ASCII_CSV) {
427         PetscCall(PetscViewerASCIIPrintf(viewer, "%" PetscInt_FMT ",%g,%" PetscInt_FMT ",%g,%g,%g\n", step_no, time, wall,
428                                          reaction_force[w * dim + 0], reaction_force[w * dim + 1], reaction_force[w * dim + 2]));
429 
430       } else {
431         PetscCall(PetscViewerASCIIPrintf(viewer, "Wall %" PetscInt_FMT " Forces: Force_x = %12g, Force_y = %12g, Force_z = %12g\n", wall,
432                                          reaction_force[w * dim + 0], reaction_force[w * dim + 1], reaction_force[w * dim + 2]));
433       }
434     }
435   }
436   PetscCall(PetscFree(reaction_force));
437   PetscFunctionReturn(0);
438 }
439 
440 // User provided TS Monitor
441 PetscErrorCode TSMonitor_NS(TS ts, PetscInt step_no, PetscReal time, Vec Q, void *ctx) {
442   User user = ctx;
443   PetscFunctionBeginUser;
444 
445   // Print every 'checkpoint_interval' steps
446   if (user->app_ctx->checkpoint_interval <= 0 || step_no % user->app_ctx->checkpoint_interval != 0 ||
447       (user->app_ctx->cont_steps == step_no && step_no != 0)) {
448     PetscFunctionReturn(0);
449   }
450 
451   PetscCall(WriteOutput(user, Q, step_no, time));
452 
453   PetscFunctionReturn(0);
454 }
455 
456 // TS: Create, setup, and solve
457 PetscErrorCode TSSolve_NS(DM dm, User user, AppCtx app_ctx, Physics phys, Vec *Q, PetscScalar *f_time, TS *ts) {
458   MPI_Comm    comm = user->comm;
459   TSAdapt     adapt;
460   PetscScalar final_time;
461   PetscFunctionBeginUser;
462 
463   PetscCall(TSCreate(comm, ts));
464   PetscCall(TSSetDM(*ts, dm));
465   if (phys->implicit) {
466     PetscCall(TSSetType(*ts, TSBDF));
467     if (user->op_ifunction) {
468       PetscCall(TSSetIFunction(*ts, NULL, IFunction_NS, &user));
469     } else {  // Implicit integrators can fall back to using an RHSFunction
470       PetscCall(TSSetRHSFunction(*ts, NULL, RHS_NS, &user));
471     }
472     if (user->op_ijacobian) {
473       PetscCall(DMTSSetIJacobian(dm, FormIJacobian_NS, &user));
474       if (app_ctx->amat_type) {
475         Mat Pmat, Amat;
476         PetscCall(DMCreateMatrix(dm, &Pmat));
477         PetscCall(DMSetMatType(dm, app_ctx->amat_type));
478         PetscCall(DMCreateMatrix(dm, &Amat));
479         PetscCall(TSSetIJacobian(*ts, Amat, Pmat, NULL, NULL));
480         PetscCall(MatDestroy(&Amat));
481         PetscCall(MatDestroy(&Pmat));
482       }
483     }
484   } else {
485     PetscCheck(user->op_rhs, comm, PETSC_ERR_ARG_NULL, "Problem does not provide RHSFunction");
486     PetscCall(TSSetType(*ts, TSRK));
487     PetscCall(TSRKSetType(*ts, TSRK5F));
488     PetscCall(TSSetRHSFunction(*ts, NULL, RHS_NS, &user));
489   }
490   PetscCall(TSSetMaxTime(*ts, 500. * user->units->second));
491   PetscCall(TSSetExactFinalTime(*ts, TS_EXACTFINALTIME_STEPOVER));
492   if (app_ctx->test_type == TESTTYPE_NONE) PetscCall(TSSetErrorIfStepFails(*ts, PETSC_FALSE));
493   PetscCall(TSSetTimeStep(*ts, 1.e-2 * user->units->second));
494   if (app_ctx->test_type != TESTTYPE_NONE) {
495     PetscCall(TSSetMaxSteps(*ts, 10));
496   }
497   PetscCall(TSGetAdapt(*ts, &adapt));
498   PetscCall(TSAdaptSetStepLimits(adapt, 1.e-12 * user->units->second, 1.e2 * user->units->second));
499   PetscCall(TSSetFromOptions(*ts));
500   user->time_bc_set = -1.0;    // require all BCs be updated
501   if (!app_ctx->cont_steps) {  // print initial condition
502     if (app_ctx->test_type == TESTTYPE_NONE) {
503       PetscCall(TSMonitor_NS(*ts, 0, 0., *Q, user));
504     }
505   } else {  // continue from time of last output
506     PetscInt    count;
507     PetscViewer viewer;
508 
509     if (app_ctx->cont_time <= 0) {  // Legacy files did not include step number and time
510       PetscCall(PetscViewerBinaryOpen(comm, app_ctx->cont_time_file, FILE_MODE_READ, &viewer));
511       PetscCall(PetscViewerBinaryRead(viewer, &app_ctx->cont_time, 1, &count, PETSC_REAL));
512       PetscCall(PetscViewerDestroy(&viewer));
513       PetscCheck(app_ctx->cont_steps != -1, comm, PETSC_ERR_ARG_INCOMP,
514                  "-continue step number not specified, but checkpoint file does not contain a step number (likely written by older code version)");
515     }
516     PetscCall(TSSetTime(*ts, app_ctx->cont_time * user->units->second));
517     PetscCall(TSSetStepNumber(*ts, app_ctx->cont_steps));
518   }
519   if (app_ctx->test_type == TESTTYPE_NONE) {
520     PetscCall(TSMonitorSet(*ts, TSMonitor_NS, user, NULL));
521   }
522   if (app_ctx->wall_forces.viewer) {
523     PetscCall(TSMonitorSet(*ts, TSMonitor_WallForce, user, NULL));
524   }
525   if (app_ctx->turb_spanstats_enable) {
526     PetscCall(TSMonitorSet(*ts, TSMonitor_Statistics, user, NULL));
527     CeedScalar previous_time = app_ctx->cont_time * user->units->second;
528     CeedOperatorSetContextDouble(user->spanstats.op_stats_collect_ctx->op, user->spanstats.previous_time_label, &previous_time);
529   }
530 
531   // Solve
532   PetscReal start_time;
533   PetscInt  start_step;
534   PetscCall(TSGetTime(*ts, &start_time));
535   PetscCall(TSGetStepNumber(*ts, &start_step));
536 
537   PetscPreLoadBegin(PETSC_FALSE, "Fluids Solve");
538   PetscCall(TSSetTime(*ts, start_time));
539   PetscCall(TSSetStepNumber(*ts, start_step));
540   if (PetscPreLoadingOn) {
541     // LCOV_EXCL_START
542     SNES      snes;
543     Vec       Q_preload;
544     PetscReal rtol;
545     PetscCall(VecDuplicate(*Q, &Q_preload));
546     PetscCall(VecCopy(*Q, Q_preload));
547     PetscCall(TSGetSNES(*ts, &snes));
548     PetscCall(SNESGetTolerances(snes, NULL, &rtol, NULL, NULL, NULL));
549     PetscCall(SNESSetTolerances(snes, PETSC_DEFAULT, .99, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT));
550     PetscCall(TSSetSolution(*ts, *Q));
551     PetscCall(TSStep(*ts));
552     PetscCall(SNESSetTolerances(snes, PETSC_DEFAULT, rtol, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT));
553     PetscCall(VecDestroy(&Q_preload));
554     // LCOV_EXCL_STOP
555   } else {
556     PetscCall(PetscBarrier((PetscObject)*ts));
557     PetscCall(TSSolve(*ts, *Q));
558   }
559   PetscPreLoadEnd();
560 
561   PetscCall(TSGetSolveTime(*ts, &final_time));
562   *f_time = final_time;
563 
564   if (app_ctx->test_type == TESTTYPE_NONE) {
565     PetscInt step_no;
566     PetscCall(TSGetStepNumber(*ts, &step_no));
567     if (user->app_ctx->checkpoint_interval > 0 || user->app_ctx->checkpoint_interval == -1) {
568       PetscCall(WriteOutput(user, *Q, step_no, final_time));
569     }
570 
571     PetscLogEvent stage_id;
572     PetscStageLog stage_log;
573 
574     PetscCall(PetscLogStageGetId("Fluids Solve", &stage_id));
575     PetscCall(PetscLogGetStageLog(&stage_log));
576     PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Time taken for solution (sec): %g\n", stage_log->stageInfo[stage_id].perfInfo.time));
577   }
578   PetscFunctionReturn(0);
579 }
580