xref: /petsc/src/ts/tests/ex30.c (revision f4f49eeac7efa77fffa46b7ff95a3ed169f659ed)
1 static char help[] = "Grid based Landau collision operator with PIC interface with OpenMP setup. (one species per grid)\n";
2 
3 /*
4    Support 2.5V with axisymmetric coordinates
5      - r,z coordinates
6      - Domain and species data input by Landau operator
7      - "radius" for each grid, normalized with electron thermal velocity
8      - Domain: (0,radius) x (-radius,radius), thus first coordinate x[0] is perpendicular velocity and 2pi*x[0] term is added for axisymmetric
9    Supports full 3V
10 
11  */
12 
13 #include <petscdmplex.h>
14 #include <petscds.h>
15 #include <petscdmswarm.h>
16 #include <petscksp.h>
17 #include <petsc/private/petscimpl.h>
18 #if defined(PETSC_HAVE_OPENMP) && defined(PETSC_HAVE_THREADSAFETY)
19   #include <omp.h>
20 #endif
21 #include <petsclandau.h>
22 #include <petscdmcomposite.h>
23 
24 typedef struct {
25   Mat MpTrans;
26   Mat Mp;
27   Vec ff;
28   Vec uu;
29 } MatShellCtx;
30 
31 typedef struct {
32   PetscInt   v_target;
33   PetscInt   g_target;
34   PetscInt   global_vertex_id_0;
35   DM        *globSwarmArray;
36   LandauCtx *ctx;
37   DM        *grid_dm;
38   Mat       *g_Mass;
39   Mat       *globMpArray;
40   Vec       *globXArray;
41   PetscBool  print;
42   PetscBool  print_entropy;
43 } PrintCtx;
44 
45 PetscErrorCode MatMultMtM_SeqAIJ(Mat MtM, Vec xx, Vec yy)
46 {
47   MatShellCtx *matshellctx;
48 
49   PetscFunctionBeginUser;
50   PetscCall(MatShellGetContext(MtM, &matshellctx));
51   PetscCheck(matshellctx, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "No context");
52   PetscCall(MatMult(matshellctx->Mp, xx, matshellctx->ff));
53   PetscCall(MatMult(matshellctx->MpTrans, matshellctx->ff, yy));
54   PetscFunctionReturn(PETSC_SUCCESS);
55 }
56 
57 PetscErrorCode MatMultAddMtM_SeqAIJ(Mat MtM, Vec xx, Vec yy, Vec zz)
58 {
59   MatShellCtx *matshellctx;
60 
61   PetscFunctionBeginUser;
62   PetscCall(MatShellGetContext(MtM, &matshellctx));
63   PetscCheck(matshellctx, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "No context");
64   PetscCall(MatMult(matshellctx->Mp, xx, matshellctx->ff));
65   PetscCall(MatMultAdd(matshellctx->MpTrans, matshellctx->ff, yy, zz));
66   PetscFunctionReturn(PETSC_SUCCESS);
67 }
68 
69 PetscErrorCode createSwarm(const DM dm, PetscInt dim, DM *sw)
70 {
71   PetscInt Nc = 1;
72 
73   PetscFunctionBeginUser;
74   PetscCall(DMCreate(PETSC_COMM_SELF, sw));
75   PetscCall(DMSetType(*sw, DMSWARM));
76   PetscCall(DMSetDimension(*sw, dim));
77   PetscCall(DMSwarmSetType(*sw, DMSWARM_PIC));
78   PetscCall(DMSwarmSetCellDM(*sw, dm));
79   PetscCall(DMSwarmRegisterPetscDatatypeField(*sw, "w_q", Nc, PETSC_REAL));
80   PetscCall(DMSwarmFinalizeFieldRegister(*sw));
81   PetscCall(DMSetFromOptions(*sw));
82   PetscCall(PetscObjectSetName((PetscObject)*sw, "Particle Grid"));
83   PetscFunctionReturn(PETSC_SUCCESS);
84 }
85 
86 static PetscErrorCode makeSwarm(DM sw, const PetscInt dim, const PetscInt Np, const PetscReal xx[], const PetscReal yy[], const PetscReal zz[])
87 {
88   PetscReal    *coords;
89   PetscDataType dtype;
90   PetscInt      bs, p, zero = 0;
91 
92   PetscFunctionBeginUser;
93   PetscCall(DMSwarmSetLocalSizes(sw, Np, zero));
94   PetscCall(DMSwarmGetField(sw, "DMSwarmPIC_coor", &bs, &dtype, (void **)&coords));
95   for (p = 0; p < Np; p++) {
96     coords[p * dim + 0] = xx[p];
97     coords[p * dim + 1] = yy[p];
98     if (dim == 3) coords[p * dim + 2] = zz[p];
99   }
100   PetscCall(DMSwarmRestoreField(sw, "DMSwarmPIC_coor", &bs, &dtype, (void **)&coords));
101   PetscFunctionReturn(PETSC_SUCCESS);
102 }
103 
104 static PetscErrorCode createMp(const DM dm, DM sw, Mat *Mp_out)
105 {
106   PetscBool removePoints = PETSC_TRUE;
107   Mat       M_p;
108 
109   PetscFunctionBeginUser;
110   // migrate after coords are set
111   PetscCall(DMSwarmMigrate(sw, removePoints));
112   PetscCall(PetscObjectSetName((PetscObject)sw, "Particle Grid"));
113   /* This gives M f = \int_\Omega \phi f, which looks like a rhs for a PDE */
114   PetscCall(DMCreateMassMatrix(sw, dm, &M_p));
115   PetscCall(DMViewFromOptions(sw, NULL, "-ex30_sw_view"));
116   // output
117   *Mp_out = M_p;
118   PetscFunctionReturn(PETSC_SUCCESS);
119 }
120 
121 static PetscErrorCode particlesToGrid(const DM dm, DM sw, const PetscInt a_tid, const PetscInt dim, const PetscReal a_wp[], Vec rho, Mat M_p)
122 {
123   PetscReal    *wq;
124   PetscDataType dtype;
125   Vec           ff;
126   PetscInt      bs, p, Np;
127 
128   PetscFunctionBeginUser;
129   PetscCall(DMSwarmGetField(sw, "w_q", &bs, &dtype, (void **)&wq));
130   PetscCall(DMSwarmGetLocalSize(sw, &Np));
131   for (p = 0; p < Np; p++) wq[p] = a_wp[p];
132   PetscCall(DMSwarmRestoreField(sw, "w_q", &bs, &dtype, (void **)&wq));
133   PetscCall(PetscObjectSetName((PetscObject)rho, "rho"));
134   PetscCall(DMSwarmCreateGlobalVectorFromField(sw, "w_q", &ff));
135   PetscCall(PetscObjectSetName((PetscObject)ff, "weights"));
136   PetscCall(MatMultTranspose(M_p, ff, rho));
137   PetscCall(DMSwarmDestroyGlobalVectorFromField(sw, "w_q", &ff));
138   PetscFunctionReturn(PETSC_SUCCESS);
139 }
140 
141 //
142 // add grid to arg 'sw.w_q'
143 //
144 PetscErrorCode gridToParticles(const DM dm, DM sw, const Vec rhs, Vec work, Mat M_p, Mat Mass)
145 {
146   PetscBool    is_lsqr;
147   KSP          ksp;
148   Mat          PM_p = NULL, MtM, D;
149   Vec          ff;
150   PetscInt     N, M, nzl;
151   MatShellCtx *matshellctx;
152   PC           pc;
153 
154   PetscFunctionBeginUser;
155   // (Mp Mp)^-1 M
156   PetscCall(MatMult(Mass, rhs, work));
157   // pseudo-inverse
158   PetscCall(KSPCreate(PETSC_COMM_SELF, &ksp));
159   PetscCall(KSPSetType(ksp, KSPCG));
160   PetscCall(KSPGetPC(ksp, &pc));
161   PetscCall(PCSetType(pc, PCJACOBI));
162   PetscCall(KSPSetOptionsPrefix(ksp, "ftop_"));
163   PetscCall(KSPSetFromOptions(ksp));
164   PetscCall(PetscObjectTypeCompare((PetscObject)ksp, KSPLSQR, &is_lsqr));
165   if (!is_lsqr) {
166     PetscCall(MatGetLocalSize(M_p, &M, &N));
167     if (N > M) {
168       PetscCall(PetscInfo(ksp, " M (%" PetscInt_FMT ") < M (%" PetscInt_FMT ") more vertices than particles: revert to lsqr\n", M, N));
169       is_lsqr = PETSC_TRUE;
170       PetscCall(KSPSetType(ksp, KSPLSQR));
171       PetscCall(PCSetType(pc, PCNONE)); // should not happen, but could solve stable (Mp Mp^T), move projection Mp before solve
172     } else {
173       PetscCall(PetscNew(&matshellctx));
174       PetscCall(MatCreateShell(PetscObjectComm((PetscObject)dm), N, N, PETSC_DECIDE, PETSC_DECIDE, matshellctx, &MtM));
175       PetscCall(MatTranspose(M_p, MAT_INITIAL_MATRIX, &matshellctx->MpTrans));
176       matshellctx->Mp = M_p;
177       PetscCall(MatShellSetOperation(MtM, MATOP_MULT, (void (*)(void))MatMultMtM_SeqAIJ));
178       PetscCall(MatShellSetOperation(MtM, MATOP_MULT_ADD, (void (*)(void))MatMultAddMtM_SeqAIJ));
179       PetscCall(MatCreateVecs(M_p, &matshellctx->uu, &matshellctx->ff));
180       PetscCall(MatCreateSeqAIJ(PETSC_COMM_SELF, N, N, 1, NULL, &D));
181       PetscCall(MatViewFromOptions(matshellctx->MpTrans, NULL, "-ftop2_Mp_mat_view"));
182       for (int i = 0; i < N; i++) {
183         const PetscScalar *vals;
184         const PetscInt    *cols;
185         PetscScalar        dot = 0;
186         PetscCall(MatGetRow(matshellctx->MpTrans, i, &nzl, &cols, &vals));
187         for (int ii = 0; ii < nzl; ii++) dot += PetscSqr(vals[ii]);
188         if (dot == 0.0) dot = 1; // empty rows
189         PetscCall(MatSetValue(D, i, i, dot, INSERT_VALUES));
190       }
191       PetscCall(MatAssemblyBegin(D, MAT_FINAL_ASSEMBLY));
192       PetscCall(MatAssemblyEnd(D, MAT_FINAL_ASSEMBLY));
193       PetscCall(PetscInfo(M_p, "createMtMKSP Have %" PetscInt_FMT " eqs, nzl = %" PetscInt_FMT "\n", N, nzl));
194       PetscCall(KSPSetOperators(ksp, MtM, D));
195       PetscCall(MatViewFromOptions(D, NULL, "-ftop2_D_mat_view"));
196       PetscCall(MatViewFromOptions(M_p, NULL, "-ftop2_Mp_mat_view"));
197       PetscCall(MatViewFromOptions(matshellctx->MpTrans, NULL, "-ftop2_MpTranspose_mat_view"));
198       PetscCall(MatViewFromOptions(MtM, NULL, "-ftop2_MtM_mat_view"));
199     }
200   }
201   if (is_lsqr) {
202     PC        pc;
203     PetscBool is_bjac;
204     PetscCall(KSPGetPC(ksp, &pc));
205     PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCBJACOBI, &is_bjac));
206     if (is_bjac) {
207       PetscCall(DMSwarmCreateMassMatrixSquare(sw, dm, &PM_p));
208       PetscCall(KSPSetOperators(ksp, M_p, PM_p));
209     } else {
210       PetscCall(KSPSetOperators(ksp, M_p, M_p));
211     }
212   }
213   PetscCall(DMSwarmCreateGlobalVectorFromField(sw, "w_q", &ff)); // this grabs access
214   if (!is_lsqr) {
215     PetscCall(KSPSolve(ksp, work, matshellctx->uu));
216     PetscCall(MatMult(M_p, matshellctx->uu, ff));
217     PetscCall(MatDestroy(&matshellctx->MpTrans));
218     PetscCall(VecDestroy(&matshellctx->ff));
219     PetscCall(VecDestroy(&matshellctx->uu));
220     PetscCall(MatDestroy(&D));
221     PetscCall(MatDestroy(&MtM));
222     PetscCall(PetscFree(matshellctx));
223   } else {
224     PetscCall(KSPSolveTranspose(ksp, work, ff));
225   }
226   PetscCall(KSPDestroy(&ksp));
227   PetscCall(MatDestroy(&PM_p));
228   PetscCall(DMSwarmDestroyGlobalVectorFromField(sw, "w_q", &ff));
229   PetscFunctionReturn(PETSC_SUCCESS);
230 }
231 
232 #define EX30_MAX_NUM_THRDS 12
233 #define EX30_MAX_BATCH_SZ  1024
234 //
235 // add grid to arg 'globSwarmArray[].w_q'
236 //
237 PetscErrorCode gridToParticles_private(DM grid_dm[], DM globSwarmArray[], const PetscInt dim, const PetscInt v_target, const PetscInt numthreads, const PetscInt num_vertices, const PetscInt global_vertex_id, Mat globMpArray[], Mat g_Mass[], Vec t_fhat[][EX30_MAX_NUM_THRDS], PetscReal moments[], Vec globXArray[], LandauCtx *ctx)
238 {
239   PetscErrorCode ierr = (PetscErrorCode)0; // used for inside thread loops
240 
241   PetscFunctionBeginUser;
242   // map back to particles
243   for (PetscInt v_id_0 = 0; v_id_0 < ctx->batch_sz; v_id_0 += numthreads) {
244     PetscCall(PetscInfo(grid_dm[0], "g2p: global batch %" PetscInt_FMT " of %" PetscInt_FMT ", Landau batch %" PetscInt_FMT " of %" PetscInt_FMT ": map back to particles\n", global_vertex_id + 1, num_vertices, v_id_0 + 1, ctx->batch_sz));
245     //PetscPragmaOMP(parallel for)
246     for (int tid = 0; tid < numthreads; tid++) {
247       const PetscInt v_id = v_id_0 + tid, glb_v_id = global_vertex_id + v_id;
248       if (glb_v_id < num_vertices) {
249         for (PetscInt grid = 0; grid < ctx->num_grids; grid++) { // add same particels for all grids
250           PetscErrorCode ierr_t;
251           ierr_t = PetscInfo(grid_dm[0], "gridToParticles: global batch %" PetscInt_FMT ", local batch b=%" PetscInt_FMT ", grid g=%" PetscInt_FMT ", index(b,g) %" PetscInt_FMT "\n", global_vertex_id, v_id, grid, LAND_PACK_IDX(v_id, grid));
252           ierr_t = gridToParticles(grid_dm[grid], globSwarmArray[LAND_PACK_IDX(v_id, grid)], globXArray[LAND_PACK_IDX(v_id, grid)], t_fhat[grid][tid], globMpArray[LAND_PACK_IDX(v_id, grid)], g_Mass[grid]);
253           if (ierr_t) ierr = ierr_t;
254         }
255       }
256     }
257     PetscCheck(!ierr, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Error in OMP loop. ierr = %d", (int)ierr);
258     /* Get moments */
259     PetscCall(PetscInfo(grid_dm[0], "Cleanup batches %" PetscInt_FMT " to %" PetscInt_FMT "\n", v_id_0, v_id_0 + numthreads));
260     for (int tid = 0; tid < numthreads; tid++) {
261       const PetscInt v_id = v_id_0 + tid, glb_v_id = global_vertex_id + v_id;
262       if (glb_v_id == v_target) {
263         for (PetscInt grid = 0; grid < ctx->num_grids; grid++) {
264           PetscDataType dtype;
265           PetscReal    *wp, *coords;
266           DM            sw = globSwarmArray[LAND_PACK_IDX(v_id, grid)];
267           PetscInt      npoints, bs = 1;
268           PetscCall(DMSwarmGetField(sw, "w_q", &bs, &dtype, (void **)&wp)); // take data out here
269           PetscCall(DMSwarmGetField(sw, "DMSwarmPIC_coor", &bs, &dtype, (void **)&coords));
270           PetscCall(DMSwarmGetLocalSize(sw, &npoints));
271           for (int p = 0; p < npoints; p++) {
272             PetscReal v2 = 0, fact = (dim == 2) ? 2.0 * PETSC_PI * coords[p * dim + 0] : 1, w = fact * wp[p] * ctx->n_0 * ctx->masses[ctx->species_offset[grid]];
273             for (int i = 0; i < dim; ++i) v2 += PetscSqr(coords[p * dim + i]);
274             moments[0] += w;
275             moments[1] += w * ctx->v_0 * coords[p * dim + 1]; // z-momentum
276             moments[2] += w * 0.5 * ctx->v_0 * ctx->v_0 * v2;
277           }
278           PetscCall(DMSwarmRestoreField(sw, "w_q", &bs, &dtype, (void **)&wp));
279           PetscCall(DMSwarmRestoreField(sw, "DMSwarmPIC_coor", &bs, &dtype, (void **)&coords));
280         }
281         const PetscReal N_inv = 1 / moments[0];
282         PetscCall(PetscInfo(grid_dm[0], "gridToParticles_private [%" PetscInt_FMT "], n = %g\n", v_id, (double)moments[0]));
283         for (PetscInt grid = 0; grid < ctx->num_grids; grid++) {
284           PetscDataType dtype;
285           PetscReal    *wp, *coords;
286           DM            sw = globSwarmArray[LAND_PACK_IDX(v_id, grid)];
287           PetscInt      npoints, bs = 1;
288           PetscCall(DMSwarmGetField(sw, "w_q", &bs, &dtype, (void **)&wp)); // take data out here
289           PetscCall(DMSwarmGetField(sw, "DMSwarmPIC_coor", &bs, &dtype, (void **)&coords));
290           PetscCall(DMSwarmGetLocalSize(sw, &npoints));
291           for (int p = 0; p < npoints; p++) {
292             const PetscReal fact = dim == 2 ? 2.0 * PETSC_PI * coords[p * dim + 0] : 1, w = fact * wp[p] * ctx->n_0 * ctx->masses[ctx->species_offset[grid]], ww = w * N_inv;
293             if (w > PETSC_REAL_MIN) {
294               moments[3] -= ww * PetscLogReal(ww);
295               PetscCheck(ww < 1 - PETSC_MACHINE_EPSILON, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "ww (%g) > 1", (double)ww);
296             } else moments[4] -= w;
297           }
298           PetscCall(DMSwarmRestoreField(sw, "w_q", &bs, &dtype, (void **)&wp));
299           PetscCall(DMSwarmRestoreField(sw, "DMSwarmPIC_coor", &bs, &dtype, (void **)&coords));
300         }
301       }
302     } // thread batch
303   }   // batch
304   PetscFunctionReturn(PETSC_SUCCESS);
305 }
306 
307 static void maxwellian(PetscInt dim, const PetscReal x[], PetscReal kt_m, PetscReal n, PetscReal shift, PetscScalar *u)
308 {
309   PetscInt  i;
310   PetscReal v2 = 0, theta = 2.0 * kt_m; /* theta = 2kT/mc^2 */
311 
312   if (shift != 0.) {
313     v2 = 0;
314     for (i = 0; i < dim - 1; ++i) v2 += x[i] * x[i];
315     v2 += (x[dim - 1] - shift) * (x[dim - 1] - shift);
316     /* evaluate the shifted Maxwellian */
317     u[0] += n * PetscPowReal(PETSC_PI * theta, -1.5) * (PetscExpReal(-v2 / theta));
318   } else {
319     /* compute the exponents, v^2 */
320     for (i = 0; i < dim; ++i) v2 += x[i] * x[i];
321     /* evaluate the Maxwellian */
322     u[0] += n * PetscPowReal(PETSC_PI * theta, -1.5) * (PetscExpReal(-v2 / theta));
323   }
324 }
325 
326 static PetscErrorCode PostStep(TS ts)
327 {
328   PetscInt   n, dim, nDMs, v_id;
329   PetscReal  t;
330   LandauCtx *ctx;
331   Vec        X;
332   PrintCtx  *printCtx;
333   DM         pack;
334   PetscReal  moments[5], e_grid[LANDAU_MAX_GRIDS];
335 
336   PetscFunctionBeginUser;
337   PetscCall(TSGetApplicationContext(ts, &printCtx));
338   if (!printCtx->print && !printCtx->print_entropy) PetscFunctionReturn(PETSC_SUCCESS);
339   ctx = printCtx->ctx;
340   if (printCtx->v_target < printCtx->global_vertex_id_0 || printCtx->v_target >= printCtx->global_vertex_id_0 + ctx->batch_sz) PetscFunctionReturn(PETSC_SUCCESS);
341   for (int i = 0; i < 5; i++) moments[i] = 0;
342   for (int i = 0; i < LANDAU_MAX_GRIDS; i++) e_grid[i] = 0;
343   v_id = printCtx->v_target % ctx->batch_sz;
344   PetscCall(TSGetDM(ts, &pack));
345   PetscCall(DMGetDimension(pack, &dim));
346   PetscCall(DMCompositeGetNumberDM(pack, &nDMs)); // number of vertices * number of grids
347   PetscCall(TSGetSolution(ts, &X));
348   PetscCall(TSGetStepNumber(ts, &n));
349   PetscCall(TSGetTime(ts, &t));
350   PetscCall(DMCompositeGetAccessArray(pack, X, nDMs, NULL, printCtx->globXArray));
351   if (printCtx->print_entropy && printCtx->v_target >= 0) {
352     for (PetscInt grid = 0; grid < ctx->num_grids; grid++) {
353       PetscDataType dtype;
354       PetscReal    *wp, *coords;
355       DM            sw = printCtx->globSwarmArray[LAND_PACK_IDX(v_id, grid)];
356       Vec           work, subX = printCtx->globXArray[LAND_PACK_IDX(v_id, grid)];
357       PetscInt      bs, NN;
358       // C-G moments
359       PetscCall(VecDuplicate(subX, &work));
360       PetscCall(gridToParticles(printCtx->grid_dm[grid], sw, subX, work, printCtx->globMpArray[LAND_PACK_IDX(v_id, grid)], printCtx->g_Mass[grid]));
361       PetscCall(VecDestroy(&work));
362       // moments
363       PetscCall(DMSwarmGetField(sw, "DMSwarmPIC_coor", &bs, &dtype, (void **)&coords));
364       PetscCall(DMSwarmGetLocalSize(sw, &NN));
365       PetscCall(DMSwarmGetField(sw, "w_q", &bs, &dtype, (void **)&wp));
366       for (int pp = 0; pp < NN; pp++) {
367         PetscReal v2 = 0, fact = (dim == 2) ? 2.0 * PETSC_PI * coords[pp * dim + 0] : 1, w = fact * wp[pp] * ctx->n_0 * ctx->masses[ctx->species_offset[grid]];
368         for (int i = 0; i < dim; ++i) v2 += PetscSqr(coords[pp * dim + i]);
369         moments[0] += w;
370         moments[1] += w * ctx->v_0 * coords[pp * dim + 1]; // z-momentum
371         moments[2] += w * 0.5 * ctx->v_0 * ctx->v_0 * v2;
372         e_grid[grid] += w * 0.5 * ctx->v_0 * ctx->v_0 * v2;
373       }
374       PetscCall(DMSwarmRestoreField(sw, "DMSwarmPIC_coor", &bs, &dtype, (void **)&coords));
375       PetscCall(DMSwarmRestoreField(sw, "w_q", &bs, &dtype, (void **)&wp));
376     }
377     // entropy
378     const PetscReal N_inv = 1 / moments[0];
379     for (PetscInt grid = 0; grid < ctx->num_grids; grid++) {
380       PetscDataType dtype;
381       PetscReal    *wp, *coords;
382       DM            sw = printCtx->globSwarmArray[LAND_PACK_IDX(v_id, grid)];
383       PetscInt      bs, NN;
384       PetscCall(DMSwarmGetField(sw, "DMSwarmPIC_coor", &bs, &dtype, (void **)&coords));
385       PetscCall(DMSwarmGetLocalSize(sw, &NN));
386       PetscCall(DMSwarmGetField(sw, "w_q", &bs, &dtype, (void **)&wp));
387       for (int pp = 0; pp < NN; pp++) {
388         PetscReal fact = (dim == 2) ? 2.0 * PETSC_PI * coords[pp * dim + 0] : 1, w = fact * wp[pp] * ctx->n_0 * ctx->masses[ctx->species_offset[grid]], ww = w * N_inv;
389         if (w > PETSC_REAL_MIN) {
390           moments[3] -= ww * PetscLogReal(ww);
391           PetscCheck(ww < 1 - PETSC_MACHINE_EPSILON, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "ww (%g) > 1", (double)ww);
392         } else moments[4] -= w;
393       }
394       PetscCall(DMSwarmRestoreField(sw, "DMSwarmPIC_coor", &bs, &dtype, (void **)&coords));
395       PetscCall(DMSwarmRestoreField(sw, "w_q", &bs, &dtype, (void **)&wp));
396     }
397     PetscCall(PetscInfo(X, "%4d) time %e, Landau particle moments: 0: %18.12e 1: %19.12e 2: %18.12e entropy: %e loss %e. energy = %e + %e + %e\n", (int)n, (double)t, (double)moments[0], (double)moments[1], (double)moments[2], (double)moments[3], (double)moments[4], (double)e_grid[0], (double)e_grid[1], (double)e_grid[2]));
398   }
399   if (printCtx->print && printCtx->g_target >= 0) {
400     PetscInt         grid   = printCtx->g_target, id;
401     static PetscReal last_t = -100000, period = .5;
402     if (last_t == -100000) last_t = -period + t;
403     if (t >= last_t + period) {
404       last_t = t;
405       PetscCall(DMGetOutputSequenceNumber(ctx->plex[grid], &id, NULL));
406       PetscCall(DMSetOutputSequenceNumber(ctx->plex[grid], id + 1, t));
407       PetscCall(VecViewFromOptions(printCtx->globXArray[LAND_PACK_IDX(v_id % ctx->batch_sz, grid)], NULL, "-ex30_vec_view"));
408       if (ctx->num_grids > grid + 1) {
409         PetscCall(DMSetOutputSequenceNumber(ctx->plex[grid + 1], id + 1, t));
410         PetscCall(VecViewFromOptions(printCtx->globXArray[LAND_PACK_IDX(v_id % ctx->batch_sz, grid + 1)], NULL, "-ex30_vec_view2"));
411       }
412       PetscCall(PetscInfo(X, "%4d) time %e View\n", (int)n, (double)t));
413     }
414   }
415   PetscCall(DMCompositeRestoreAccessArray(pack, X, nDMs, NULL, printCtx->globXArray));
416   PetscFunctionReturn(PETSC_SUCCESS);
417 }
418 
419 PetscErrorCode go(TS ts, Vec X, const PetscInt num_vertices, const PetscInt a_Np, const PetscInt dim, const PetscInt v_target, const PetscInt g_target, PetscReal shift, PetscBool use_uniform_particle_grid)
420 {
421   DM             pack, *globSwarmArray, grid_dm[LANDAU_MAX_GRIDS];
422   Mat           *globMpArray, g_Mass[LANDAU_MAX_GRIDS];
423   KSP            t_ksp[LANDAU_MAX_GRIDS][EX30_MAX_NUM_THRDS];
424   Vec            t_fhat[LANDAU_MAX_GRIDS][EX30_MAX_NUM_THRDS];
425   PetscInt       nDMs;
426   PetscErrorCode ierr = (PetscErrorCode)0; // used for inside thread loops
427 #if defined(PETSC_HAVE_OPENMP) && defined(PETSC_HAVE_THREADSAFETY)
428   PetscInt numthreads = PetscNumOMPThreads;
429 #else
430   PetscInt numthreads = 1;
431 #endif
432   LandauCtx *ctx;
433   Vec       *globXArray;
434   PetscReal  moments_0[5], moments_1a[5], moments_1b[5], dt_init;
435   PrintCtx  *printCtx;
436 
437   PetscFunctionBeginUser;
438   PetscCheck(numthreads <= EX30_MAX_NUM_THRDS, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Too many threads %" PetscInt_FMT " > %d", numthreads, EX30_MAX_NUM_THRDS);
439   PetscCheck(numthreads > 0, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Number threads %" PetscInt_FMT " > %d", numthreads, EX30_MAX_NUM_THRDS);
440   PetscCall(TSGetDM(ts, &pack));
441   PetscCall(DMGetApplicationContext(pack, &ctx));
442   PetscCheck(ctx->batch_sz % numthreads == 0, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "batch size (-dm_landau_batch_size) %" PetscInt_FMT "  mod #threads %" PetscInt_FMT " must equal zero", ctx->batch_sz, numthreads);
443   PetscCall(DMCompositeGetNumberDM(pack, &nDMs)); // number of vertices * number of grids
444   PetscCall(PetscInfo(pack, "Have %" PetscInt_FMT " total grids, with %" PetscInt_FMT " Landau local batched and %" PetscInt_FMT " global items (vertices) %d DMs\n", ctx->num_grids, ctx->batch_sz, num_vertices, (int)nDMs));
445   PetscCall(PetscMalloc(sizeof(*globXArray) * nDMs, &globXArray));
446   PetscCall(PetscMalloc(sizeof(*globMpArray) * nDMs, &globMpArray));
447   PetscCall(PetscMalloc(sizeof(*globSwarmArray) * nDMs, &globSwarmArray));
448   // print ctx
449   PetscCall(PetscNew(&printCtx));
450   PetscCall(TSSetApplicationContext(ts, printCtx));
451   printCtx->v_target       = v_target;
452   printCtx->g_target       = g_target;
453   printCtx->ctx            = ctx;
454   printCtx->globSwarmArray = globSwarmArray;
455   printCtx->grid_dm        = grid_dm;
456   printCtx->globMpArray    = globMpArray;
457   printCtx->g_Mass         = g_Mass;
458   printCtx->globXArray     = globXArray;
459   printCtx->print_entropy  = PETSC_FALSE;
460   PetscOptionsBegin(PETSC_COMM_SELF, "", "Print Options", "DMPLEX");
461   PetscCall(PetscOptionsBool("-print_entropy", "Print entropy and moments at each time step", "ex30.c", printCtx->print_entropy, &printCtx->print_entropy, NULL));
462   PetscOptionsEnd();
463   // view
464   PetscCall(DMViewFromOptions(ctx->plex[g_target], NULL, "-ex30_dm_view"));
465   if (ctx->num_grids > g_target + 1) { PetscCall(DMViewFromOptions(ctx->plex[g_target + 1], NULL, "-ex30_dm_view2")); }
466   // create mesh mass matrices
467   PetscCall(VecZeroEntries(X));
468   PetscCall(DMCompositeGetAccessArray(pack, X, nDMs, NULL, globXArray)); // just to duplicate
469   for (PetscInt grid = 0; grid < ctx->num_grids; grid++) {               // add same particels for all grids
470     Vec          subX = globXArray[LAND_PACK_IDX(0, grid)];
471     DM           dm   = ctx->plex[grid];
472     PetscSection s;
473     grid_dm[grid] = dm;
474     PetscCall(DMCreateMassMatrix(dm, dm, &g_Mass[grid]));
475     //
476     PetscCall(DMGetLocalSection(dm, &s));
477     PetscCall(DMPlexCreateClosureIndex(dm, s));
478     for (int tid = 0; tid < numthreads; tid++) {
479       PC pc;
480       PetscCall(VecDuplicate(subX, &t_fhat[grid][tid]));
481       PetscCall(KSPCreate(PETSC_COMM_SELF, &t_ksp[grid][tid]));
482       PetscCall(KSPSetType(t_ksp[grid][tid], KSPCG));
483       PetscCall(KSPGetPC(t_ksp[grid][tid], &pc));
484       PetscCall(PCSetType(pc, PCJACOBI));
485       PetscCall(KSPSetOptionsPrefix(t_ksp[grid][tid], "ptof_"));
486       PetscCall(KSPSetOperators(t_ksp[grid][tid], g_Mass[grid], g_Mass[grid]));
487       PetscCall(KSPSetFromOptions(t_ksp[grid][tid]));
488     }
489   }
490   PetscCall(DMCompositeRestoreAccessArray(pack, X, nDMs, NULL, globXArray));
491   PetscCall(TSGetTimeStep(ts, &dt_init)); // we could have an adaptive time stepper
492   // loop over all vertices in chucks that are batched for TSSolve
493   for (int i = 0; i < 5; i++) moments_0[i] = moments_1a[i] = moments_1b[i] = 0;
494   for (PetscInt global_vertex_id_0 = 0; global_vertex_id_0 < num_vertices; global_vertex_id_0 += ctx->batch_sz, shift /= 2) { // outer vertex loop
495     PetscCall(TSSetTime(ts, 0));
496     PetscCall(TSSetStepNumber(ts, 0));
497     PetscCall(TSSetTimeStep(ts, dt_init));
498     PetscCall(DMCompositeGetAccessArray(pack, X, nDMs, NULL, globXArray));
499     printCtx->global_vertex_id_0 = global_vertex_id_0;
500     if (v_target >= global_vertex_id_0 && v_target < global_vertex_id_0 + ctx->batch_sz) {
501       PetscCall(PetscObjectSetName((PetscObject)globXArray[LAND_PACK_IDX(v_target % ctx->batch_sz, g_target)], "rho"));
502       printCtx->print = PETSC_TRUE;
503     } else printCtx->print = PETSC_FALSE;
504     // create fake particles in batches with threads
505     for (PetscInt v_id_0 = 0; v_id_0 < ctx->batch_sz; v_id_0 += numthreads) {
506       PetscReal *xx_t[LANDAU_MAX_GRIDS][EX30_MAX_NUM_THRDS], *yy_t[LANDAU_MAX_GRIDS][EX30_MAX_NUM_THRDS], *zz_t[LANDAU_MAX_GRIDS][EX30_MAX_NUM_THRDS], *wp_t[LANDAU_MAX_GRIDS][EX30_MAX_NUM_THRDS];
507       PetscInt   Np_t[LANDAU_MAX_GRIDS][EX30_MAX_NUM_THRDS];
508       // make particles
509       for (int tid = 0; tid < numthreads; tid++) {
510         const PetscInt v_id = v_id_0 + tid, glb_v_id = global_vertex_id_0 + v_id;
511         if (glb_v_id < num_vertices) {                                                                                                                                            // the ragged edge (in last batch)
512           PetscInt Npp0 = a_Np + (glb_v_id % (a_Np / 10 + 1)), nTargetP[LANDAU_MAX_GRIDS];                                                                                        // n of particels in each dim with load imbalance
513           for (PetscInt grid = 0; grid < ctx->num_grids; grid++) {                                                                                                                // add same particels for all grids
514             const PetscReal kT_m  = ctx->k * ctx->thermal_temps[ctx->species_offset[grid]] / ctx->masses[ctx->species_offset[grid]] / (ctx->v_0 * ctx->v_0);                      /* theta = 2kT/mc^2 per species */
515             PetscReal       lo[3] = {-ctx->radius[grid], -ctx->radius[grid], -ctx->radius[grid]}, hi[3] = {ctx->radius[grid], ctx->radius[grid], ctx->radius[grid]}, hp[3], vole; // would be nice to get box from DM
516             PetscInt        Npi = Npp0, Npj = 2 * Npp0, Npk = 1;
517             PetscRandom     rand;
518             PetscReal       sigma = ctx->thermal_speed[grid] / ctx->thermal_speed[0], p2_shift = grid == 0 ? shift : -shift;
519             PetscCall(PetscRandomCreate(PETSC_COMM_SELF, &rand));
520             PetscCall(PetscRandomSetInterval(rand, 0., 1.));
521             PetscCall(PetscRandomSetFromOptions(rand));
522             if (dim == 2) lo[0] = 0; // Landau coordinate (r,z)
523             else Npi = Npj = Npk = Npp0;
524             // User: use glb_v_id to index into your data
525             const PetscInt NN = Npi * Npj * Npk; // make a regular grid of particles Npp x Npp
526             Np_t[grid][tid]   = NN;
527             if (glb_v_id == v_target) nTargetP[grid] = NN;
528             PetscCall(PetscMalloc4(NN, &xx_t[grid][tid], NN, &yy_t[grid][tid], NN, &wp_t[grid][tid], dim == 2 ? 1 : NN, &zz_t[grid][tid]));
529             hp[0] = (hi[0] - lo[0]) / Npi;
530             hp[1] = (hi[1] - lo[1]) / Npj;
531             hp[2] = (hi[2] - lo[2]) / Npk;
532             if (dim == 2) hp[2] = 1;
533             PetscCall(PetscInfo(pack, " lo = %14.7e, hi = %14.7e; hp = %14.7e, %14.7e; kT_m = %g; \n", (double)lo[1], (double)hi[1], (double)hp[0], (double)hp[1], (double)kT_m)); // temp
534             vole = hp[0] * hp[1] * hp[2] * ctx->n[grid];                                                                                                                           // fix for multi-species
535             PetscCall(PetscInfo(pack, "Vertex %" PetscInt_FMT ", grid %" PetscInt_FMT " with %" PetscInt_FMT " particles (diagnostic target = %" PetscInt_FMT ")\n", glb_v_id, grid, NN, v_target));
536             for (int pj = 0, pp = 0; pj < Npj; pj++) {
537               for (int pk = 0; pk < Npk; pk++) {
538                 for (int pi = 0; pi < Npi; pi++, pp++) {
539                   PetscReal p_shift   = p2_shift;
540                   wp_t[grid][tid][pp] = 0;
541                   if (use_uniform_particle_grid) {
542                     xx_t[grid][tid][pp] = lo[0] + hp[0] / 2.0 + pi * hp[0];
543                     yy_t[grid][tid][pp] = lo[1] + hp[1] / 2.0 + pj * hp[1];
544                     if (dim == 3) zz_t[grid][tid][pp] = lo[2] + hp[2] / 2.0 + pk * hp[2];
545                     PetscReal x[] = {xx_t[grid][tid][pp], yy_t[grid][tid][pp], dim == 2 ? 0 : zz_t[grid][tid][pp]};
546                     p_shift *= ctx->thermal_speed[grid] / ctx->v_0;
547                     maxwellian(dim, x, kT_m, vole, p_shift, &wp_t[grid][tid][pp]);
548                     if (ctx->num_grids == 1 && shift != 0) { // bi-maxwellian, electron plasma
549                       maxwellian(dim, x, kT_m, vole, -p_shift, &wp_t[grid][tid][pp]);
550                     }
551                   } else {
552                     PetscReal u1, u2;
553                     do {
554                       do {
555                         PetscCall(PetscRandomGetValueReal(rand, &u1));
556                       } while (u1 == 0);
557                       PetscCall(PetscRandomGetValueReal(rand, &u2));
558                       //compute z0 and z1
559                       PetscReal mag       = sigma * PetscSqrtReal(-2.0 * PetscLogReal(u1));
560                       xx_t[grid][tid][pp] = mag * PetscCosReal(2.0 * PETSC_PI * u2);
561                       yy_t[grid][tid][pp] = mag * PetscSinReal(2.0 * PETSC_PI * u2);
562                       if (dim == 2 && xx_t[grid][tid][pp] < lo[0]) xx_t[grid][tid][pp] = -xx_t[grid][tid][pp];
563                       if (dim == 3) zz_t[grid][tid][pp] = lo[2] + hp[2] / 2.0 + pk * hp[2];
564                       if (ctx->num_grids == 1 && pp % 2 == 0) p_shift = 0; // one species, split bi-max
565                       p_shift *= ctx->thermal_speed[grid] / ctx->v_0;
566                       if (dim == 3) zz_t[grid][tid][pp] += p_shift;
567                       else yy_t[grid][tid][pp] += p_shift;
568                       wp_t[grid][tid][pp] += ctx->n[grid] / NN * PetscSqrtReal(ctx->masses[ctx->species_offset[grid]] / ctx->masses[0]);
569                       if (p_shift <= 0) break; // add bi-max for electron plasma only
570                       p_shift = -p_shift;
571                     } while (ctx->num_grids == 1); // add bi-max for electron plasma only
572                   }
573                   {
574                     if (glb_v_id == v_target) {
575                       PetscReal x[] = {xx_t[grid][tid][pp], yy_t[grid][tid][pp], dim == 2 ? 0 : zz_t[grid][tid][pp]};
576                       PetscReal v2 = 0, fact = dim == 2 ? 2.0 * PETSC_PI * x[0] : 1, w = fact * wp_t[grid][tid][pp] * ctx->n_0 * ctx->masses[ctx->species_offset[grid]];
577                       for (int i = 0; i < dim; ++i) v2 += PetscSqr(x[i]);
578                       moments_0[0] += w;                   // not thread safe
579                       moments_0[1] += w * ctx->v_0 * x[1]; // z-momentum
580                       moments_0[2] += w * 0.5 * ctx->v_0 * ctx->v_0 * v2;
581                     }
582                   }
583                 }
584               }
585             }
586             PetscCall(PetscRandomDestroy(&rand));
587           }
588           // entropy init, need global n
589           if (glb_v_id == v_target) {
590             const PetscReal N_inv = 1 / moments_0[0];
591             PetscCall(PetscInfo(pack, "Target %" PetscInt_FMT " with %" PetscInt_FMT " particels\n", glb_v_id, nTargetP[0]));
592             for (PetscInt grid = 0; grid < ctx->num_grids; grid++) {
593               const PetscInt NN = nTargetP[grid];
594               for (int pp = 0; pp < NN; pp++) {
595                 const PetscReal fact = dim == 2 ? 2.0 * PETSC_PI * xx_t[grid][tid][pp] : 1, w = fact * ctx->n_0 * ctx->masses[ctx->species_offset[grid]] * wp_t[grid][tid][pp], ww = w * N_inv;
596                 if (w > PETSC_REAL_MIN) {
597                   moments_0[3] -= ww * PetscLogReal(ww);
598                   PetscCheck(ww < 1 - PETSC_MACHINE_EPSILON, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "ww (%g) > 1", (double)ww);
599                 } else moments_0[4] -= w;
600               }
601             } // grid
602           }   // target
603         }     // active
604       }       // threads
605       /* Create particle swarm */
606       for (int tid = 0; tid < numthreads; tid++) {
607         const PetscInt v_id = v_id_0 + tid, glb_v_id = global_vertex_id_0 + v_id;
608         if (glb_v_id < num_vertices) {                             // the ragged edge of the last batch
609           for (PetscInt grid = 0; grid < ctx->num_grids; grid++) { // add same particels for all grids
610             PetscErrorCode ierr_t;
611             PetscSection   section;
612             PetscInt       Nf;
613             DM             dm = grid_dm[grid];
614             ierr_t            = DMGetLocalSection(dm, &section);
615             ierr_t            = PetscSectionGetNumFields(section, &Nf);
616             if (Nf != 1) ierr_t = (PetscErrorCode)9999;
617             else {
618               ierr_t = DMViewFromOptions(dm, NULL, "-dm_view");
619               ierr_t = PetscInfo(pack, "call createSwarm [%" PetscInt_FMT ".%" PetscInt_FMT "] local block index %" PetscInt_FMT "\n", v_id, grid, LAND_PACK_IDX(v_id, grid));
620               ierr_t = createSwarm(dm, dim, &globSwarmArray[LAND_PACK_IDX(v_id, grid)]);
621             }
622             if (ierr_t) ierr = ierr_t;
623           }
624         } // active
625       }   // threads
626       PetscCheck(ierr != 9999, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Only support one species per grid");
627       PetscCheck(!ierr, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Error in OMP loop. ierr = %d", (int)ierr);
628       // make globMpArray
629       PetscPragmaOMP(parallel for)
630       for (int tid = 0; tid < numthreads; tid++) {
631         const PetscInt v_id = v_id_0 + tid, glb_v_id = global_vertex_id_0 + v_id;
632         if (glb_v_id < num_vertices) {
633           for (PetscInt grid = 0; grid < ctx->num_grids; grid++) { // add same particels for all grids
634             PetscErrorCode ierr_t;
635             DM             sw = globSwarmArray[LAND_PACK_IDX(v_id, grid)];
636             ierr_t            = PetscInfo(pack, "makeSwarm %" PetscInt_FMT ".%" PetscInt_FMT ") for block %" PetscInt_FMT "\n", v_id, grid, LAND_PACK_IDX(v_id, grid));
637             ierr_t            = makeSwarm(sw, dim, Np_t[grid][tid], xx_t[grid][tid], yy_t[grid][tid], zz_t[grid][tid]);
638             if (ierr_t) ierr = ierr_t;
639           }
640         }
641       }
642       //PetscPragmaOMP(parallel for)
643       for (int tid = 0; tid < numthreads; tid++) {
644         const PetscInt v_id = v_id_0 + tid, glb_v_id = global_vertex_id_0 + v_id;
645         if (glb_v_id < num_vertices) {
646           for (PetscInt grid = 0; grid < ctx->num_grids; grid++) { // add same particels for all grids
647             PetscErrorCode ierr_t;
648             DM             dm = grid_dm[grid];
649             DM             sw = globSwarmArray[LAND_PACK_IDX(v_id, grid)];
650             ierr_t            = PetscInfo(pack, "createMp %" PetscInt_FMT ".%" PetscInt_FMT ") for block %" PetscInt_FMT "\n", v_id, grid, LAND_PACK_IDX(v_id, grid));
651             ierr_t            = createMp(dm, sw, &globMpArray[LAND_PACK_IDX(v_id, grid)]);
652             if (ierr_t) ierr = ierr_t;
653           }
654         }
655       }
656       PetscCheck(!ierr, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Error in OMP loop. ierr = %d", (int)ierr);
657       // p --> g: set X
658       // PetscPragmaOMP(parallel for)
659       for (int tid = 0; tid < numthreads; tid++) {
660         const PetscInt v_id = v_id_0 + tid, glb_v_id = global_vertex_id_0 + v_id;
661         if (glb_v_id < num_vertices) {
662           for (PetscInt grid = 0; grid < ctx->num_grids; grid++) { // add same particels for all grids
663             PetscErrorCode ierr_t;
664             DM             dm   = grid_dm[grid];
665             DM             sw   = globSwarmArray[LAND_PACK_IDX(v_id, grid)];
666             Vec            subX = globXArray[LAND_PACK_IDX(v_id, grid)], work = t_fhat[grid][tid];
667             ierr_t = PetscInfo(pack, "particlesToGrid %" PetscInt_FMT ".%" PetscInt_FMT ") for block %" PetscInt_FMT "\n", v_id, grid, LAND_PACK_IDX(v_id, grid));
668             ierr_t = particlesToGrid(dm, sw, tid, dim, wp_t[grid][tid], subX, globMpArray[LAND_PACK_IDX(v_id, grid)]);
669             if (ierr_t) ierr = ierr_t;
670             // u = M^_1 f_w
671             ierr_t = VecCopy(subX, work);
672             ierr_t = KSPSolve(t_ksp[grid][tid], work, subX);
673             if (ierr_t) ierr = ierr_t;
674           }
675         }
676       }
677       PetscCheck(!ierr, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Error in OMP loop. ierr = %d", (int)ierr);
678       /* Cleanup */
679       for (int tid = 0; tid < numthreads; tid++) {
680         const PetscInt v_id = v_id_0 + tid, glb_v_id = global_vertex_id_0 + v_id;
681         if (glb_v_id < num_vertices) {
682           for (PetscInt grid = 0; grid < ctx->num_grids; grid++) { // add same particels for all grids
683             PetscCall(PetscFree4(xx_t[grid][tid], yy_t[grid][tid], wp_t[grid][tid], zz_t[grid][tid]));
684           }
685         } // active
686       }   // threads
687     }     // (fake) particle loop
688     // standard view of initial conditions
689     if (v_target >= global_vertex_id_0 && v_target < global_vertex_id_0 + ctx->batch_sz) {
690       PetscCall(DMSetOutputSequenceNumber(ctx->plex[g_target], 0, 0.0));
691       PetscCall(VecViewFromOptions(globXArray[LAND_PACK_IDX(v_target % ctx->batch_sz, g_target)], NULL, "-ex30_vec_view"));
692       if (ctx->num_grids > g_target + 1) {
693         PetscCall(DMSetOutputSequenceNumber(ctx->plex[g_target + 1], 0, 0.0));
694         PetscCall(VecViewFromOptions(globXArray[LAND_PACK_IDX(v_target % ctx->batch_sz, g_target + 1)], NULL, "-ex30_vec_view2"));
695       }
696     }
697     // coarse graining moments
698     if (v_target >= global_vertex_id_0 && v_target < global_vertex_id_0 + ctx->batch_sz && printCtx->print_entropy) {
699       const PetscInt v_id = v_target % ctx->batch_sz;
700       for (PetscInt grid = 0; grid < ctx->num_grids; grid++) {
701         PetscDataType dtype;
702         PetscReal    *wp, *coords;
703         DM            sw = globSwarmArray[LAND_PACK_IDX(v_id, grid)];
704         Vec           work, subX = globXArray[LAND_PACK_IDX(v_id, grid)];
705         PetscInt      bs, NN;
706         // C-G moments
707         PetscCall(VecDuplicate(subX, &work));
708         PetscCall(gridToParticles(grid_dm[grid], sw, subX, work, globMpArray[LAND_PACK_IDX(v_id, grid)], g_Mass[grid]));
709         PetscCall(VecDestroy(&work));
710         // moments
711         PetscCall(DMSwarmGetField(sw, "DMSwarmPIC_coor", &bs, &dtype, (void **)&coords));
712         PetscCall(DMSwarmGetLocalSize(sw, &NN));
713         PetscCall(DMSwarmGetField(sw, "w_q", &bs, &dtype, (void **)&wp));
714         for (int pp = 0; pp < NN; pp++) {
715           PetscReal v2 = 0, fact = (dim == 2) ? 2.0 * PETSC_PI * coords[pp * dim + 0] : 1, w = fact * wp[pp] * ctx->n_0 * ctx->masses[ctx->species_offset[grid]];
716           for (int i = 0; i < dim; ++i) v2 += PetscSqr(coords[pp * dim + i]);
717           moments_1a[0] += w;
718           moments_1a[1] += w * ctx->v_0 * coords[pp * dim + 1]; // z-momentum
719           moments_1a[2] += w * 0.5 * ctx->v_0 * ctx->v_0 * v2;
720         }
721         PetscCall(DMSwarmRestoreField(sw, "DMSwarmPIC_coor", &bs, &dtype, (void **)&coords));
722         PetscCall(DMSwarmRestoreField(sw, "w_q", &bs, &dtype, (void **)&wp));
723       }
724       // entropy
725       const PetscReal N_inv = 1 / moments_1a[0];
726       PetscCall(PetscInfo(pack, "Entropy batch %" PetscInt_FMT " of %" PetscInt_FMT ", n = %g\n", v_target, num_vertices, (double)(1 / N_inv)));
727       for (PetscInt grid = 0; grid < ctx->num_grids; grid++) {
728         PetscDataType dtype;
729         PetscReal    *wp, *coords;
730         DM            sw = globSwarmArray[LAND_PACK_IDX(v_id, grid)];
731         PetscInt      bs, NN;
732         PetscCall(DMSwarmGetLocalSize(sw, &NN));
733         PetscCall(DMSwarmGetField(sw, "w_q", &bs, &dtype, (void **)&wp));
734         PetscCall(DMSwarmGetField(sw, "DMSwarmPIC_coor", &bs, &dtype, (void **)&coords));
735         for (int pp = 0; pp < NN; pp++) {
736           PetscReal fact = (dim == 2) ? 2.0 * PETSC_PI * coords[pp * dim + 0] : 1, w = fact * wp[pp] * ctx->n_0 * ctx->masses[ctx->species_offset[grid]], ww = w * N_inv;
737           if (w > PETSC_REAL_MIN) {
738             moments_1a[3] -= ww * PetscLogReal(ww);
739             PetscCheck(ww < 1 - PETSC_MACHINE_EPSILON, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "ww (%g) > 1", (double)ww);
740           } else moments_1a[4] -= w;
741         }
742         PetscCall(DMSwarmRestoreField(sw, "w_q", &bs, &dtype, (void **)&wp));
743         PetscCall(DMSwarmRestoreField(sw, "DMSwarmPIC_coor", &bs, &dtype, (void **)&coords));
744       }
745     }
746     // restore vector
747     PetscCall(DMCompositeRestoreAccessArray(pack, X, nDMs, NULL, globXArray));
748     // view
749     if (v_target >= global_vertex_id_0 && v_target < global_vertex_id_0 + ctx->batch_sz) { PetscCall(DMPlexLandauPrintNorms(X, 0)); }
750     // advance
751     PetscCall(TSSetSolution(ts, X));
752     PetscCall(PetscInfo(pack, "Advance vertex %" PetscInt_FMT " to %" PetscInt_FMT "\n", global_vertex_id_0, global_vertex_id_0 + ctx->batch_sz));
753     PetscCall(TSSetPostStep(ts, PostStep));
754     PetscCall(PostStep(ts));
755     PetscCall(TSSolve(ts, X));
756     // view
757     PetscCall(DMCompositeGetAccessArray(pack, X, nDMs, NULL, globXArray));
758     if (v_target >= global_vertex_id_0 && v_target < global_vertex_id_0 + ctx->batch_sz) {
759       DM        sw = globSwarmArray[LAND_PACK_IDX(v_target % ctx->batch_sz, g_target)];
760       PetscInt  id;
761       PetscReal t;
762       PetscCall(DMPlexLandauPrintNorms(X, 1));
763       PetscCall(TSGetTime(ts, &t));
764       PetscCall(DMGetOutputSequenceNumber(ctx->plex[g_target], &id, NULL));
765       PetscCall(DMSetOutputSequenceNumber(ctx->plex[g_target], id + 1, t));
766       PetscCall(VecViewFromOptions(globXArray[LAND_PACK_IDX(v_target % ctx->batch_sz, g_target)], NULL, "-ex30_vec_view"));
767       if (ctx->num_grids > g_target + 1) {
768         PetscCall(DMSetOutputSequenceNumber(ctx->plex[g_target + 1], id + 1, t));
769         PetscCall(VecViewFromOptions(globXArray[LAND_PACK_IDX(v_target % ctx->batch_sz, g_target + 1)], NULL, "-ex30_vec_view2"));
770       }
771       /* Visualize particle field */
772       Vec f;
773       PetscCall(DMSetOutputSequenceNumber(sw, 0, 0.0));
774       PetscCall(DMViewFromOptions(grid_dm[g_target], NULL, "-weights_dm_view"));
775       PetscCall(DMViewFromOptions(sw, NULL, "-weights_sw_view"));
776       PetscCall(DMSwarmCreateGlobalVectorFromField(sw, "w_q", &f));
777       PetscCall(PetscObjectSetName((PetscObject)f, "weights"));
778       PetscCall(VecViewFromOptions(f, NULL, "-weights_vec_view"));
779       PetscCall(DMSwarmDestroyGlobalVectorFromField(sw, "w_q", &f));
780     }
781     // particles to grid, compute moments and entropy
782     if (v_target >= global_vertex_id_0 && v_target < global_vertex_id_0 + ctx->batch_sz && printCtx->print_entropy) {
783       PetscCall(gridToParticles_private(grid_dm, globSwarmArray, dim, v_target, numthreads, num_vertices, global_vertex_id_0, globMpArray, g_Mass, t_fhat, moments_1b, globXArray, ctx));
784       PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Particle Moments:\t number density      momentum (par)     energy             entropy      loss : # OMP threads %g\n", (double)numthreads));
785       PetscCall(PetscPrintf(PETSC_COMM_WORLD, "\tInitial:         %18.12e %19.12e %18.12e %e %e\n", (double)moments_0[0], (double)moments_0[1], (double)moments_0[2], (double)moments_0[3], (double)moments_0[4]));
786       PetscCall(PetscPrintf(PETSC_COMM_WORLD, "\tCoarse-graining: %18.12e %19.12e %18.12e %e %e\n", (double)moments_1a[0], (double)moments_1a[1], (double)moments_1a[2], (double)moments_1a[3], (double)moments_1a[4]));
787       PetscCall(PetscPrintf(PETSC_COMM_WORLD, "\tLandau:          %18.12e %19.12e %18.12e %e %e\n", (double)moments_1b[0], (double)moments_1b[1], (double)moments_1b[2], (double)moments_1b[3], (double)moments_1b[4]));
788       PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Coarse-graining entropy generation = %e ; Landau entropy generation = %e\n", (double)(moments_1a[3] - moments_0[3]), (double)(moments_1b[3] - moments_0[3])));
789       PetscCall(PetscPrintf(PETSC_COMM_WORLD, "(relative) energy conservation: Coarse-graining = %e ; Landau = %e\n", (double)(moments_1a[2] - moments_0[2]) / (double)moments_0[2], (double)(moments_1b[2] - moments_0[2]) / (double)moments_0[2]));
790     }
791     // restore vector
792     PetscCall(DMCompositeRestoreAccessArray(pack, X, nDMs, NULL, globXArray));
793     // cleanup
794     for (PetscInt v_id_0 = 0; v_id_0 < ctx->batch_sz; v_id_0 += numthreads) {
795       for (int tid = 0; tid < numthreads; tid++) {
796         const PetscInt v_id = v_id_0 + tid, glb_v_id = global_vertex_id_0 + v_id;
797         if (glb_v_id < num_vertices) {
798           for (PetscInt grid = 0; grid < ctx->num_grids; grid++) {
799             PetscCall(DMDestroy(&globSwarmArray[LAND_PACK_IDX(v_id, grid)]));
800             PetscCall(MatDestroy(&globMpArray[LAND_PACK_IDX(v_id, grid)]));
801           }
802         }
803       }
804     }
805   } // user batch, not used
806   /* Cleanup */
807   PetscCall(PetscFree(globXArray));
808   PetscCall(PetscFree(globSwarmArray));
809   PetscCall(PetscFree(globMpArray));
810   PetscCall(PetscFree(printCtx));
811   // clean up mass matrices
812   for (PetscInt grid = 0; grid < ctx->num_grids; grid++) { // add same particels for all grids
813     PetscCall(MatDestroy(&g_Mass[grid]));
814     for (int tid = 0; tid < numthreads; tid++) {
815       PetscCall(VecDestroy(&t_fhat[grid][tid]));
816       PetscCall(KSPDestroy(&t_ksp[grid][tid]));
817     }
818   }
819   PetscFunctionReturn(PETSC_SUCCESS);
820 }
821 
822 int main(int argc, char **argv)
823 {
824   DM         pack;
825   Vec        X;
826   PetscInt   dim = 2, num_vertices = 1, Np = 10, v_target = 0, g_target = 0;
827   TS         ts;
828   Mat        J;
829   LandauCtx *ctx;
830   PetscReal  shift                     = 0;
831   PetscBool  use_uniform_particle_grid = PETSC_TRUE;
832 
833   PetscFunctionBeginUser;
834   PetscCall(PetscInitialize(&argc, &argv, NULL, help));
835   // process args
836   PetscOptionsBegin(PETSC_COMM_SELF, "", "Collision Options", "DMPLEX");
837   PetscCall(PetscOptionsInt("-dim", "Velocity space dimension", "ex30.c", dim, &dim, NULL));
838   PetscCall(PetscOptionsInt("-number_spatial_vertices", "Number of user spatial vertices to be batched for Landau", "ex30.c", num_vertices, &num_vertices, NULL));
839   PetscCall(PetscOptionsInt("-number_particles_per_dimension", "Number of particles per grid, with slight modification per spatial vertex, in each dimension of base Cartesian grid", "ex30.c", Np, &Np, NULL));
840   PetscCall(PetscOptionsBool("-use_uniform_particle_grid", "Use uniform particle grid", "ex30.c", use_uniform_particle_grid, &use_uniform_particle_grid, NULL));
841   PetscCall(PetscOptionsInt("-vertex_view_target", "Global vertex for diagnostics", "ex30.c", v_target, &v_target, NULL));
842   PetscCall(PetscOptionsReal("-e_shift", "Bim-Maxwellian shift", "ex30.c", shift, &shift, NULL));
843   PetscCheck(v_target < num_vertices, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Batch to view %" PetscInt_FMT " should be < number of vertices %" PetscInt_FMT, v_target, num_vertices);
844   PetscCall(PetscOptionsInt("-grid_view_target", "Grid to view with diagnostics", "ex30.c", g_target, &g_target, NULL));
845   PetscOptionsEnd();
846   /* Create a mesh */
847   PetscCall(DMPlexLandauCreateVelocitySpace(PETSC_COMM_SELF, dim, "", &X, &J, &pack));
848   PetscCall(DMSetUp(pack));
849   PetscCall(DMSetOutputSequenceNumber(pack, 0, 0.0));
850   PetscCall(DMGetApplicationContext(pack, &ctx));
851   PetscCheck(g_target < ctx->num_grids, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Grid to view %" PetscInt_FMT " should be < number of grids %" PetscInt_FMT, g_target, ctx->num_grids);
852   PetscCheck(ctx->batch_view_idx == v_target % ctx->batch_sz, PETSC_COMM_WORLD, PETSC_ERR_ARG_OUTOFRANGE, "Global view index %" PetscInt_FMT " mode batch size %" PetscInt_FMT " != ctx->batch_view_idx %" PetscInt_FMT, v_target, ctx->batch_sz, ctx->batch_view_idx);
853   /* Create timestepping solver context */
854   PetscCall(TSCreate(PETSC_COMM_SELF, &ts));
855   PetscCall(TSSetDM(ts, pack));
856   PetscCall(TSSetIFunction(ts, NULL, DMPlexLandauIFunction, NULL));
857   PetscCall(TSSetIJacobian(ts, J, J, DMPlexLandauIJacobian, NULL));
858   PetscCall(TSSetExactFinalTime(ts, TS_EXACTFINALTIME_STEPOVER));
859   PetscCall(TSSetFromOptions(ts));
860   PetscCall(PetscObjectSetName((PetscObject)X, "X"));
861   // do particle advance
862   PetscCall(go(ts, X, num_vertices, Np, dim, v_target, g_target, shift, use_uniform_particle_grid));
863   PetscCall(MatZeroEntries(J)); // need to zero out so as to not reuse it in Landau's logic
864   /* clean up */
865   PetscCall(DMPlexLandauDestroyVelocitySpace(&pack));
866   PetscCall(TSDestroy(&ts));
867   PetscCall(VecDestroy(&X));
868   PetscCall(PetscFinalize());
869   return 0;
870 }
871 
872 /*TEST
873 
874   build:
875     requires: !complex
876 
877   testset:
878     requires: double defined(PETSC_USE_DMLANDAU_2D)
879     output_file: output/ex30_0.out
880     args: -dim 2 -petscspace_degree 3 -dm_landau_num_species_grid 1,1,1 -dm_refine 1 -number_particles_per_dimension 10 -dm_plex_hash_location \
881           -dm_landau_batch_size 4 -number_spatial_vertices 6 -vertex_view_target 5 -grid_view_target 1 -dm_landau_batch_view_idx 1 \
882           -dm_landau_n 1.000018,1,1e-6 -dm_landau_thermal_temps 2,1,1 -dm_landau_ion_masses 2,180 -dm_landau_ion_charges 1,18 \
883           -ftop_ksp_rtol 1e-10 -ftop_ksp_type lsqr -ftop_pc_type bjacobi -ftop_sub_pc_factor_shift_type nonzero -ftop_sub_pc_type lu \
884           -ksp_type preonly -pc_type lu -dm_landau_verbose 4 -print_entropy \
885           -ptof_ksp_type cg -ptof_pc_type jacobi -ptof_ksp_rtol 1e-12\
886           -snes_converged_reason -snes_monitor -snes_rtol 1e-14 -snes_stol 1e-14 \
887           -ts_dt 0.01 -ts_rtol 1e-1 -ts_exact_final_time stepover -ts_max_snes_failures -1 -ts_max_steps 1 -ts_monitor -ts_type beuler
888 
889     test:
890       suffix: cpu
891       args: -dm_landau_device_type cpu
892     test:
893       suffix: kokkos
894       requires: kokkos_kernels !openmp
895       args: -dm_landau_device_type kokkos -dm_mat_type aijkokkos -dm_vec_type kokkos -pc_type bjkokkos -pc_bjkokkos_ksp_type tfqmr -pc_bjkokkos_pc_type jacobi
896 
897   testset:
898     requires: double !defined(PETSC_USE_DMLANDAU_2D)
899     output_file: output/ex30_3d.out
900     args: -dim 3 -petscspace_degree 2 -dm_landau_num_species_grid 1,1,1 -dm_refine 0 -number_particles_per_dimension 10 -dm_plex_hash_location \
901           -dm_landau_batch_size 1 -number_spatial_vertices 1 -vertex_view_target 0 -grid_view_target 0 -dm_landau_batch_view_idx 0 \
902           -dm_landau_n 1.000018,1,1e-6 -dm_landau_thermal_temps 2,1,1 -dm_landau_ion_masses 2,180 -dm_landau_ion_charges 1,18 \
903           -ftop_ksp_rtol 1e-12 -ksp_type preonly -pc_type lu \
904           -ptof_ksp_type cg -ptof_pc_type jacobi -ptof_ksp_rtol 1e-12\
905           -snes_converged_reason -snes_monitor -snes_rtol 1e-12 -snes_stol 1e-12\
906           -ts_dt 0.1 -ts_exact_final_time stepover -ts_max_snes_failures -1 -ts_max_steps 1 -ts_monitor -ts_type beuler -print_entropy
907 
908     test:
909       suffix: cpu_3d
910       args: -dm_landau_device_type cpu
911     test:
912       suffix: kokkos_3d
913       requires: kokkos_kernels !openmp
914       args: -dm_landau_device_type kokkos -dm_mat_type aijkokkos -dm_vec_type kokkos -pc_type bjkokkos -pc_bjkokkos_ksp_type tfqmr -pc_bjkokkos_pc_type jacobi
915 
916   testset:
917     requires: !complex double defined(PETSC_USE_DMLANDAU_2D) !cuda
918     args: -dm_refine 1 -dm_landau_num_species_grid 1 -dm_landau_thermal_temps 1 -petscspace_degree 3 -snes_converged_reason -ts_type beuler -ts_dt .01 \
919           -ts_max_steps 1 -ksp_type preonly -pc_type lu -snes_rtol 1e-12 -snes_stol 1e-12 -dm_landau_device_type cpu -number_particles_per_dimension 40 \
920           -ptof_ksp_rtol 1e-12 -dm_landau_batch_size 4 -number_spatial_vertices 4 -grid_view_target 0 \
921           -vertex_view_target 3 -dm_landau_batch_view_idx 3
922     test:
923       suffix: simple
924       args: -ex30_dm_view
925     test:
926       requires: cgns
927       suffix: cgns
928       args: -ex30_vec_view cgns:cgnsDi.cgns
929     test:
930       suffix: normal
931       args: -ex30_dm_view -use_uniform_particle_grid false
932 
933 TEST*/
934