xref: /libCEED/examples/petsc/bps.c (revision 432a1099cb1d389d6aaa27cea90787a26d24ee77)
1 // Copyright (c) 2017, Lawrence Livermore National Security, LLC. Produced at
2 // the Lawrence Livermore National Laboratory. LLNL-CODE-734707. All Rights
3 // reserved. See files LICENSE and NOTICE for details.
4 //
5 // This file is part of CEED, a collection of benchmarks, miniapps, software
6 // libraries and APIs for efficient high-order finite element and spectral
7 // element discretizations for exascale applications. For more information and
8 // source code availability see http://github.com/ceed.
9 //
10 // The CEED research is supported by the Exascale Computing Project 17-SC-20-SC,
11 // a collaborative effort of two U.S. Department of Energy organizations (Office
12 // of Science and the National Nuclear Security Administration) responsible for
13 // the planning and preparation of a capable exascale ecosystem, including
14 // software, applications, hardware, advanced system engineering and early
15 // testbed platforms, in support of the nation's exascale computing imperative.
16 
17 //                        libCEED + PETSc Example: CEED BPs
18 //
19 // This example demonstrates a simple usage of libCEED with PETSc to solve the
20 // CEED BP benchmark problems, see http://ceed.exascaleproject.org/bps.
21 //
22 // The code is intentionally "raw", using only low-level communication
23 // primitives.
24 //
25 // Build with:
26 //
27 //     make bps [PETSC_DIR=</path/to/petsc>] [CEED_DIR=</path/to/libceed>]
28 //
29 // Sample runs:
30 //
31 //     bps -problem bp1
32 //     bps -problem bp2 -ceed /cpu/self
33 //     bps -problem bp3 -ceed /gpu/occa
34 //     bps -problem bp4 -ceed /cpu/occa
35 //     bps -problem bp5 -ceed /omp/occa
36 //     bps -problem bp6 -ceed /ocl/occa
37 //
38 //TESTARGS -ceed {ceed_resource} -test -problem bp2
39 
40 /// @file
41 /// CEED BPs example using PETSc
42 /// See bpsdmplex.c for an implementation using DMPlex unstructured grids.
43 const char help[] = "Solve CEED BPs using PETSc\n";
44 
45 #include <stdbool.h>
46 #include <string.h>
47 #include "common.h"
48 #include "bp1.h"
49 #include "bp2.h"
50 #include "bp3.h"
51 #include "bp4.h"
52 
53 #define PATH(BASE) __DIR__ #BASE
54 
55 static void Split3(PetscInt size, PetscInt m[3], bool reverse) {
56   for (PetscInt d=0,sizeleft=size; d<3; d++) {
57     PetscInt try = (PetscInt)PetscCeilReal(PetscPowReal(sizeleft, 1./(3 - d)));
58     while (try * (sizeleft / try) != sizeleft) try++;
59     m[reverse ? 2-d : d] = try;
60     sizeleft /= try;
61   }
62 }
63 
64 static PetscInt Max3(const PetscInt a[3]) {
65   return PetscMax(a[0], PetscMax(a[1], a[2]));
66 }
67 static PetscInt Min3(const PetscInt a[3]) {
68   return PetscMin(a[0], PetscMin(a[1], a[2]));
69 }
70 static void GlobalNodes(const PetscInt p[3], const PetscInt irank[3],
71                       PetscInt degree, const PetscInt melem[3],
72                       PetscInt mnodes[3]) {
73   for (int d=0; d<3; d++)
74     mnodes[d] = degree*melem[d] + (irank[d] == p[d]-1);
75 }
76 static PetscInt GlobalStart(const PetscInt p[3], const PetscInt irank[3],
77                             PetscInt degree, const PetscInt melem[3]) {
78   PetscInt start = 0;
79   // Dumb brute-force is easier to read
80   for (PetscInt i=0; i<p[0]; i++) {
81     for (PetscInt j=0; j<p[1]; j++) {
82       for (PetscInt k=0; k<p[2]; k++) {
83         PetscInt mnodes[3], ijkrank[] = {i,j,k};
84         if (i == irank[0] && j == irank[1] && k == irank[2]) return start;
85         GlobalNodes(p, ijkrank, degree, melem, mnodes);
86         start += mnodes[0] * mnodes[1] * mnodes[2];
87       }
88     }
89   }
90   return -1;
91 }
92 static int CreateRestriction(Ceed ceed, const CeedInt melem[3],
93                              CeedInt P, CeedInt ncomp,
94                              CeedElemRestriction *Erestrict) {
95   const PetscInt nelem = melem[0]*melem[1]*melem[2];
96   PetscInt mnodes[3], *idx, *idxp;
97 
98   // Get indicies
99   for (int d=0; d<3; d++) mnodes[d] = melem[d]*(P-1) + 1;
100   idxp = idx = malloc(nelem*P*P*P*sizeof idx[0]);
101   for (CeedInt i=0; i<melem[0]; i++) {
102     for (CeedInt j=0; j<melem[1]; j++) {
103       for (CeedInt k=0; k<melem[2]; k++,idxp += P*P*P) {
104         for (CeedInt ii=0; ii<P; ii++) {
105           for (CeedInt jj=0; jj<P; jj++) {
106             for (CeedInt kk=0; kk<P; kk++) {
107               if (0) { // This is the C-style (i,j,k) ordering that I prefer
108                 idxp[(ii*P+jj)*P+kk] = (((i*(P-1)+ii)*mnodes[1]
109                                          + (j*(P-1)+jj))*mnodes[2]
110                                         + (k*(P-1)+kk));
111               } else { // (k,j,i) ordering for consistency with MFEM example
112                 idxp[ii+P*(jj+P*kk)] = (((i*(P-1)+ii)*mnodes[1]
113                                          + (j*(P-1)+jj))*mnodes[2]
114                                         + (k*(P-1)+kk));
115               }
116             }
117           }
118         }
119       }
120     }
121   }
122 
123   // Setup CEED restriction
124   CeedElemRestrictionCreate(ceed, nelem, P*P*P, mnodes[0]*mnodes[1]*mnodes[2], ncomp,
125                             CEED_MEM_HOST, CEED_OWN_POINTER, idx, Erestrict);
126 
127   PetscFunctionReturn(0);
128 }
129 
130 // Data for PETSc
131 typedef struct User_ *User;
132 struct User_ {
133   MPI_Comm comm;
134   VecScatter ltog;              // Scatter for all entries
135   VecScatter ltog0;             // Skip Dirichlet values
136   VecScatter gtogD;             // global-to-global; only Dirichlet values
137   Vec Xloc, Yloc;
138   CeedVector xceed, yceed;
139   CeedOperator op;
140   CeedVector rho;
141   Ceed ceed;
142 };
143 
144 // BP Options
145 typedef enum {
146   CEED_BP1 = 0, CEED_BP2 = 1, CEED_BP3 = 2,
147   CEED_BP4 = 3, CEED_BP5 = 4, CEED_BP6 = 5
148 } bpType;
149 static const char *const bpTypes[] = {"bp1","bp2","bp3","bp4","bp5","bp6",
150                                       "bpType","CEED_BP",0};
151 
152 // BP specific data
153 typedef struct {
154   CeedInt vscale, qdatasize, qextra;
155   CeedQFunctionUser setup, apply, error;
156   const char setupfname[PETSC_MAX_PATH_LEN], applyfname[PETSC_MAX_PATH_LEN],
157         errorfname[PETSC_MAX_PATH_LEN];
158   CeedEvalMode inmode, outmode;
159   CeedQuadMode qmode;
160 } bpData;
161 
162 bpData bpOptions[6] = {
163   [CEED_BP1] = {
164     .vscale = 1,
165     .qdatasize = 1,
166     .qextra = 1,
167     .setup = SetupMass,
168     .apply = Mass,
169     .error = Error,
170     .setupfname = PATH(bp1.h:SetupMass),
171     .applyfname = PATH(bp1.h:Mass),
172     .errorfname = PATH(common.h:Error),
173     .inmode = CEED_EVAL_INTERP,
174     .outmode = CEED_EVAL_INTERP,
175     .qmode = CEED_GAUSS
176   },
177   [CEED_BP2] = {
178     .vscale = 3,
179     .qdatasize = 1,
180     .qextra = 1,
181     .setup = SetupMass3,
182     .apply = Mass3,
183     .error = Error3,
184     .setupfname = PATH(bp2.h:SetupMass3),
185     .applyfname = PATH(bp2.h:Mass3),
186     .errorfname = PATH(common.h:Error3),
187     .inmode = CEED_EVAL_INTERP,
188     .outmode = CEED_EVAL_INTERP,
189     .qmode = CEED_GAUSS
190   },
191   [CEED_BP3] = {
192     .vscale = 1,
193     .qdatasize = 6,
194     .qextra = 1,
195     .setup = SetupDiff,
196     .apply = Diff,
197     .error = Error,
198     .setupfname = PATH(bp3.h:SetupDiff),
199     .applyfname = PATH(bp3.h:Diff),
200     .errorfname = PATH(common.h:Error),
201     .inmode = CEED_EVAL_GRAD,
202     .outmode = CEED_EVAL_GRAD,
203     .qmode = CEED_GAUSS
204   },
205   [CEED_BP4] = {
206     .vscale = 3,
207     .qdatasize = 6,
208     .qextra = 1,
209     .setup = SetupDiff3,
210     .apply = Diff3,
211     .error = Error3,
212     .setupfname = PATH(bp4.h:SetupDiff3),
213     .applyfname = PATH(bp4.h:Diff3),
214     .errorfname = PATH(common.h:Error3),
215     .inmode = CEED_EVAL_GRAD,
216     .outmode = CEED_EVAL_GRAD,
217     .qmode = CEED_GAUSS
218   },
219   [CEED_BP5] = {
220     .vscale = 1,
221     .qdatasize = 6,
222     .qextra = 0,
223     .setup = SetupDiff,
224     .apply = Diff,
225     .error = Error,
226     .setupfname = PATH(bp3.h:SetupDiff),
227     .applyfname = PATH(bp3.h:Diff),
228     .errorfname = PATH(common.h:Error),
229     .inmode = CEED_EVAL_GRAD,
230     .outmode = CEED_EVAL_GRAD,
231     .qmode = CEED_GAUSS_LOBATTO
232   },
233   [CEED_BP6] = {
234     .vscale = 3,
235     .qdatasize = 6,
236     .qextra = 0,
237     .setup = SetupDiff3,
238     .apply = Diff3,
239     .error = Error3,
240     .setupfname = PATH(bp4.h:SetupDiff3),
241     .applyfname = PATH(bp4.h:Diff3),
242     .errorfname = PATH(common.h:Error3),
243     .inmode = CEED_EVAL_GRAD,
244     .outmode = CEED_EVAL_GRAD,
245     .qmode = CEED_GAUSS_LOBATTO
246   }
247 };
248 
249 // This function uses libCEED to compute the action of the mass matrix
250 static PetscErrorCode MatMult_Mass(Mat A, Vec X, Vec Y) {
251   PetscErrorCode ierr;
252   User user;
253   PetscScalar *x, *y;
254 
255   PetscFunctionBeginUser;
256   ierr = MatShellGetContext(A, &user); CHKERRQ(ierr);
257   ierr = VecScatterBegin(user->ltog, X, user->Xloc, INSERT_VALUES,
258                          SCATTER_REVERSE); CHKERRQ(ierr);
259   ierr = VecScatterEnd(user->ltog, X, user->Xloc, INSERT_VALUES, SCATTER_REVERSE);
260   CHKERRQ(ierr);
261   ierr = VecZeroEntries(user->Yloc); CHKERRQ(ierr);
262 
263   ierr = VecGetArrayRead(user->Xloc, (const PetscScalar **)&x); CHKERRQ(ierr);
264   ierr = VecGetArray(user->Yloc, &y); CHKERRQ(ierr);
265   CeedVectorSetArray(user->xceed, CEED_MEM_HOST, CEED_USE_POINTER, x);
266   CeedVectorSetArray(user->yceed, CEED_MEM_HOST, CEED_USE_POINTER, y);
267 
268   CeedOperatorApply(user->op, user->xceed, user->yceed,
269                     CEED_REQUEST_IMMEDIATE);
270   ierr = CeedVectorSyncArray(user->yceed, CEED_MEM_HOST); CHKERRQ(ierr);
271 
272   ierr = VecRestoreArrayRead(user->Xloc, (const PetscScalar **)&x); CHKERRQ(ierr);
273   ierr = VecRestoreArray(user->Yloc, &y); CHKERRQ(ierr);
274 
275   if (Y) {
276     ierr = VecZeroEntries(Y); CHKERRQ(ierr);
277     ierr = VecScatterBegin(user->ltog, user->Yloc, Y, ADD_VALUES, SCATTER_FORWARD);
278     CHKERRQ(ierr);
279     ierr = VecScatterEnd(user->ltog, user->Yloc, Y, ADD_VALUES, SCATTER_FORWARD);
280     CHKERRQ(ierr);
281   }
282   PetscFunctionReturn(0);
283 }
284 
285 // This function uses libCEED to compute the action of the Laplacian with
286 // Dirichlet boundary conditions
287 static PetscErrorCode MatMult_Diff(Mat A, Vec X, Vec Y) {
288   PetscErrorCode ierr;
289   User user;
290   PetscScalar *x, *y;
291 
292   PetscFunctionBeginUser;
293   ierr = MatShellGetContext(A, &user); CHKERRQ(ierr);
294 
295   // Global-to-local
296   ierr = VecScatterBegin(user->ltog0, X, user->Xloc, INSERT_VALUES,
297                          SCATTER_REVERSE); CHKERRQ(ierr);
298   ierr = VecScatterEnd(user->ltog0, X, user->Xloc, INSERT_VALUES,
299                        SCATTER_REVERSE);
300   CHKERRQ(ierr);
301   ierr = VecZeroEntries(user->Yloc); CHKERRQ(ierr);
302 
303   // Setup CEED vectors
304   ierr = VecGetArrayRead(user->Xloc, (const PetscScalar **)&x); CHKERRQ(ierr);
305   ierr = VecGetArray(user->Yloc, &y); CHKERRQ(ierr);
306   CeedVectorSetArray(user->xceed, CEED_MEM_HOST, CEED_USE_POINTER, x);
307   CeedVectorSetArray(user->yceed, CEED_MEM_HOST, CEED_USE_POINTER, y);
308 
309   // Apply CEED operator
310   CeedOperatorApply(user->op, user->xceed, user->yceed,
311                     CEED_REQUEST_IMMEDIATE);
312   ierr = CeedVectorSyncArray(user->yceed, CEED_MEM_HOST); CHKERRQ(ierr);
313 
314   // Restore PETSc vectors
315   ierr = VecRestoreArrayRead(user->Xloc, (const PetscScalar **)&x); CHKERRQ(ierr);
316   ierr = VecRestoreArray(user->Yloc, &y); CHKERRQ(ierr);
317 
318   // Local-to-global
319   ierr = VecZeroEntries(Y); CHKERRQ(ierr);
320   ierr = VecScatterBegin(user->gtogD, X, Y, INSERT_VALUES, SCATTER_FORWARD);
321   CHKERRQ(ierr);
322   ierr = VecScatterEnd(user->gtogD, X, Y, INSERT_VALUES, SCATTER_FORWARD);
323   CHKERRQ(ierr);
324   ierr = VecScatterBegin(user->ltog0, user->Yloc, Y, ADD_VALUES, SCATTER_FORWARD);
325   CHKERRQ(ierr);
326   ierr = VecScatterEnd(user->ltog0, user->Yloc, Y, ADD_VALUES, SCATTER_FORWARD);
327   CHKERRQ(ierr);
328 
329   PetscFunctionReturn(0);
330 }
331 
332 // This function calculates the error in the final solution
333 static PetscErrorCode ComputeErrorMax(User user, CeedOperator op_error, Vec X,
334                                       CeedVector target, PetscReal *maxerror) {
335   PetscErrorCode ierr;
336   PetscScalar *x;
337   CeedVector collocated_error;
338   CeedInt length;
339 
340   PetscFunctionBeginUser;
341   CeedVectorGetLength(target, &length);
342   CeedVectorCreate(user->ceed, length, &collocated_error);
343 
344   // Global-to-local
345   ierr = VecScatterBegin(user->ltog, X, user->Xloc, INSERT_VALUES,
346                          SCATTER_REVERSE); CHKERRQ(ierr);
347   ierr = VecScatterEnd(user->ltog, X, user->Xloc, INSERT_VALUES, SCATTER_REVERSE);
348   CHKERRQ(ierr);
349 
350   // Setup CEED vector
351   ierr = VecGetArrayRead(user->Xloc, (const PetscScalar **)&x); CHKERRQ(ierr);
352   CeedVectorSetArray(user->xceed, CEED_MEM_HOST, CEED_USE_POINTER, x);
353 
354   // Apply CEED operator
355   CeedOperatorApply(op_error, user->xceed, collocated_error,
356                     CEED_REQUEST_IMMEDIATE);
357 
358   // Restore PETSc vector
359   VecRestoreArrayRead(user->Xloc, (const PetscScalar **)&x); CHKERRQ(ierr);
360 
361   // Reduce max error
362   *maxerror = 0;
363   const CeedScalar *e;
364   CeedVectorGetArrayRead(collocated_error, CEED_MEM_HOST, &e);
365   for (CeedInt i=0; i<length; i++) {
366     *maxerror = PetscMax(*maxerror, PetscAbsScalar(e[i]));
367   }
368   CeedVectorRestoreArrayRead(collocated_error, &e);
369   ierr = MPI_Allreduce(MPI_IN_PLACE, maxerror,
370                        1, MPIU_REAL, MPIU_MAX, user->comm); CHKERRQ(ierr);
371 
372   // Cleanup
373   CeedVectorDestroy(&collocated_error);
374 
375   PetscFunctionReturn(0);
376 }
377 
378 int main(int argc, char **argv) {
379   PetscInt ierr;
380   MPI_Comm comm;
381   char ceedresource[PETSC_MAX_PATH_LEN] = "/cpu/self";
382   double my_rt_start, my_rt, rt_min, rt_max;
383   PetscInt degree, qextra, localnodes, localelem, melem[3], mnodes[3], p[3],
384            irank[3], lnodes[3], lsize, vscale = 1;
385   PetscScalar *r;
386   PetscBool test_mode, benchmark_mode, write_solution;
387   PetscMPIInt size, rank;
388   Vec X, Xloc, rhs, rhsloc;
389   Mat mat;
390   KSP ksp;
391   VecScatter ltog, ltog0, gtogD;
392   User user;
393   Ceed ceed;
394   CeedBasis basisx, basisu;
395   CeedElemRestriction Erestrictx, Erestrictu, Erestrictxi, Erestrictui,
396                       Erestrictqdi;
397   CeedQFunction qf_setup, qf_apply, qf_error;
398   CeedOperator op_setup, op_apply, op_error;
399   CeedVector xcoord, rho, rhsceed, target;
400   CeedInt P, Q;
401   bpType bpChoice;
402 
403   ierr = PetscInitialize(&argc, &argv, NULL, help);
404   if (ierr) return ierr;
405   comm = PETSC_COMM_WORLD;
406   ierr = PetscOptionsBegin(comm, NULL, "CEED BPs in PETSc", NULL); CHKERRQ(ierr);
407   bpChoice = CEED_BP1;
408   ierr = PetscOptionsEnum("-problem",
409                           "CEED benchmark problem to solve", NULL,
410                           bpTypes, (PetscEnum)bpChoice, (PetscEnum *)&bpChoice,
411                           NULL); CHKERRQ(ierr);
412   vscale = bpOptions[bpChoice].vscale;
413   test_mode = PETSC_FALSE;
414   ierr = PetscOptionsBool("-test",
415                           "Testing mode (do not print unless error is large)",
416                           NULL, test_mode, &test_mode, NULL); CHKERRQ(ierr);
417   benchmark_mode = PETSC_FALSE;
418   ierr = PetscOptionsBool("-benchmark",
419                           "Benchmarking mode (prints benchmark statistics)",
420                           NULL, benchmark_mode, &benchmark_mode, NULL);
421   CHKERRQ(ierr);
422   write_solution = PETSC_FALSE;
423   ierr = PetscOptionsBool("-write_solution",
424                           "Write solution for visualization",
425                           NULL, write_solution, &write_solution, NULL);
426   CHKERRQ(ierr);
427   degree = test_mode ? 3 : 1;
428   ierr = PetscOptionsInt("-degree", "Polynomial degree of tensor product basis",
429                          NULL, degree, &degree, NULL); CHKERRQ(ierr);
430   qextra = bpOptions[bpChoice].qextra;
431   ierr = PetscOptionsInt("-qextra", "Number of extra quadrature points",
432                          NULL, qextra, &qextra, NULL); CHKERRQ(ierr);
433   ierr = PetscOptionsString("-ceed", "CEED resource specifier",
434                             NULL, ceedresource, ceedresource,
435                             sizeof(ceedresource), NULL); CHKERRQ(ierr);
436   localnodes = 1000;
437   ierr = PetscOptionsInt("-local",
438                          "Target number of locally owned nodes per process",
439                          NULL, localnodes, &localnodes, NULL); CHKERRQ(ierr);
440   ierr = PetscOptionsEnd(); CHKERRQ(ierr);
441   P = degree + 1;
442   Q = P + qextra;
443 
444   // Determine size of process grid
445   ierr = MPI_Comm_size(comm, &size); CHKERRQ(ierr);
446   Split3(size, p, false);
447 
448   // Find a nicely composite number of elements no less than localnodes
449   for (localelem = PetscMax(1, localnodes / (degree*degree*degree)); ;
450        localelem++) {
451     Split3(localelem, melem, true);
452     if (Max3(melem) / Min3(melem) <= 2) break;
453   }
454 
455   // Find my location in the process grid
456   ierr = MPI_Comm_rank(comm, &rank); CHKERRQ(ierr);
457   for (int d=0,rankleft=rank; d<3; d++) {
458     const int pstride[3] = {p[1] *p[2], p[2], 1};
459     irank[d] = rankleft / pstride[d];
460     rankleft -= irank[d] * pstride[d];
461   }
462 
463   GlobalNodes(p, irank, degree, melem, mnodes);
464 
465   // Setup global vector
466   ierr = VecCreate(comm, &X); CHKERRQ(ierr);
467   ierr = VecSetSizes(X, mnodes[0]*mnodes[1]*mnodes[2]*vscale, PETSC_DECIDE);
468   CHKERRQ(ierr);
469   ierr = VecSetUp(X); CHKERRQ(ierr);
470 
471   // Print summary
472   if (!test_mode) {
473     CeedInt gsize;
474     ierr = VecGetSize(X, &gsize); CHKERRQ(ierr);
475     ierr = PetscPrintf(comm,
476                        "\n-- CEED Benchmark Problem %d -- libCEED + PETSc --\n"
477                        "  libCEED:\n"
478                        "    libCEED Backend                    : %s\n"
479                        "  Mesh:\n"
480                        "    Number of 1D Basis Nodes (p)       : %d\n"
481                        "    Number of 1D Quadrature Points (q) : %d\n"
482                        "    Global nodes                       : %D\n"
483                        "    Process Decomposition              : %D %D %D\n"
484                        "    Local Elements                     : %D = %D %D %D\n"
485                        "    Owned nodes                        : %D = %D %D %D\n",
486                        bpChoice+1, ceedresource, P, Q,  gsize/vscale, p[0],
487                        p[1], p[2], localelem, melem[0], melem[1], melem[2],
488                        mnodes[0]*mnodes[1]*mnodes[2], mnodes[0], mnodes[1], mnodes[2]);
489     CHKERRQ(ierr);
490   }
491 
492   {
493     lsize = 1;
494     for (int d=0; d<3; d++) {
495       lnodes[d] = melem[d]*degree + 1;
496       lsize *= lnodes[d];
497     }
498     ierr = VecCreate(PETSC_COMM_SELF, &Xloc); CHKERRQ(ierr);
499     ierr = VecSetSizes(Xloc, lsize*vscale, PETSC_DECIDE); CHKERRQ(ierr);
500     ierr = VecSetUp(Xloc); CHKERRQ(ierr);
501 
502     // Create local-to-global scatter
503     PetscInt *ltogind, *ltogind0, *locind, l0count;
504     IS ltogis, ltogis0, locis;
505     PetscInt gstart[2][2][2], gmnodes[2][2][2][3];
506 
507     for (int i=0; i<2; i++) {
508       for (int j=0; j<2; j++) {
509         for (int k=0; k<2; k++) {
510           PetscInt ijkrank[3] = {irank[0]+i, irank[1]+j, irank[2]+k};
511           gstart[i][j][k] = GlobalStart(p, ijkrank, degree, melem);
512           GlobalNodes(p, ijkrank, degree, melem, gmnodes[i][j][k]);
513         }
514       }
515     }
516 
517     ierr = PetscMalloc1(lsize, &ltogind); CHKERRQ(ierr);
518     ierr = PetscMalloc1(lsize, &ltogind0); CHKERRQ(ierr);
519     ierr = PetscMalloc1(lsize, &locind); CHKERRQ(ierr);
520     l0count = 0;
521     for (PetscInt i=0,ir,ii; ir=i>=mnodes[0], ii=i-ir*mnodes[0], i<lnodes[0]; i++) {
522       for (PetscInt j=0,jr,jj; jr=j>=mnodes[1], jj=j-jr*mnodes[1], j<lnodes[1]; j++) {
523         for (PetscInt k=0,kr,kk; kr=k>=mnodes[2], kk=k-kr*mnodes[2], k<lnodes[2]; k++) {
524           PetscInt here = (i*lnodes[1]+j)*lnodes[2]+k;
525           ltogind[here] =
526             gstart[ir][jr][kr] + (ii*gmnodes[ir][jr][kr][1]+jj)*gmnodes[ir][jr][kr][2]+kk;
527           if ((irank[0] == 0 && i == 0)
528               || (irank[1] == 0 && j == 0)
529               || (irank[2] == 0 && k == 0)
530               || (irank[0]+1 == p[0] && i+1 == lnodes[0])
531               || (irank[1]+1 == p[1] && j+1 == lnodes[1])
532               || (irank[2]+1 == p[2] && k+1 == lnodes[2]))
533             continue;
534           ltogind0[l0count] = ltogind[here];
535           locind[l0count++] = here;
536         }
537       }
538     }
539     ierr = ISCreateBlock(comm, vscale, lsize, ltogind, PETSC_OWN_POINTER,
540                          &ltogis); CHKERRQ(ierr);
541     ierr = VecScatterCreate(Xloc, NULL, X, ltogis, &ltog); CHKERRQ(ierr);
542     CHKERRQ(ierr);
543     ierr = ISCreateBlock(comm, vscale, l0count, ltogind0, PETSC_OWN_POINTER,
544                          &ltogis0); CHKERRQ(ierr);
545     ierr = ISCreateBlock(comm, vscale, l0count, locind, PETSC_OWN_POINTER,
546                          &locis); CHKERRQ(ierr);
547     ierr = VecScatterCreate(Xloc, locis, X, ltogis0, &ltog0); CHKERRQ(ierr);
548     {
549       // Create global-to-global scatter for Dirichlet values (everything not in
550       // ltogis0, which is the range of ltog0)
551       PetscInt xstart, xend, *indD, countD = 0;
552       IS isD;
553       const PetscScalar *x;
554       ierr = VecZeroEntries(Xloc); CHKERRQ(ierr);
555       ierr = VecSet(X, 1.0); CHKERRQ(ierr);
556       ierr = VecScatterBegin(ltog0, Xloc, X, INSERT_VALUES, SCATTER_FORWARD);
557       CHKERRQ(ierr);
558       ierr = VecScatterEnd(ltog0, Xloc, X, INSERT_VALUES, SCATTER_FORWARD);
559       CHKERRQ(ierr);
560       ierr = VecGetOwnershipRange(X, &xstart, &xend); CHKERRQ(ierr);
561       ierr = PetscMalloc1(xend-xstart, &indD); CHKERRQ(ierr);
562       ierr = VecGetArrayRead(X, &x); CHKERRQ(ierr);
563       for (PetscInt i=0; i<xend-xstart; i++) {
564         if (x[i] == 1.) indD[countD++] = xstart + i;
565       }
566       ierr = VecRestoreArrayRead(X, &x); CHKERRQ(ierr);
567       ierr = ISCreateGeneral(comm, countD, indD, PETSC_COPY_VALUES, &isD);
568       CHKERRQ(ierr);
569       ierr = PetscFree(indD); CHKERRQ(ierr);
570       ierr = VecScatterCreate(X, isD, X, isD, &gtogD); CHKERRQ(ierr);
571       ierr = ISDestroy(&isD); CHKERRQ(ierr);
572     }
573     ierr = ISDestroy(&ltogis); CHKERRQ(ierr);
574     ierr = ISDestroy(&ltogis0); CHKERRQ(ierr);
575     ierr = ISDestroy(&locis); CHKERRQ(ierr);
576   }
577 
578   // Set up libCEED
579   CeedInit(ceedresource, &ceed);
580   CeedBasisCreateTensorH1Lagrange(ceed, 3, vscale, P, Q,
581                                   bpOptions[bpChoice].qmode, &basisu);
582   CeedBasisCreateTensorH1Lagrange(ceed, 3, 3, 2, Q,
583                                   bpOptions[bpChoice].qmode, &basisx);
584 
585   CreateRestriction(ceed, melem, P, vscale, &Erestrictu);
586   CreateRestriction(ceed, melem, 2, 3, &Erestrictx);
587   CeedInt nelem = melem[0]*melem[1]*melem[2];
588   CeedElemRestrictionCreateIdentity(ceed, nelem, Q*Q*Q, nelem*Q*Q*Q, vscale,
589                                     &Erestrictui);
590   CeedElemRestrictionCreateIdentity(ceed, nelem,
591                                     Q*Q*Q,
592                                     nelem*Q*Q*Q,
593                                     bpOptions[bpChoice].qdatasize, &Erestrictqdi);
594   CeedElemRestrictionCreateIdentity(ceed, nelem, Q*Q*Q, nelem*Q*Q*Q, 1,
595                                     &Erestrictxi);
596   {
597     CeedScalar *xloc;
598     CeedInt shape[3] = {melem[0]+1, melem[1]+1, melem[2]+1}, len =
599                          shape[0]*shape[1]*shape[2];
600     xloc = malloc(len*3*sizeof xloc[0]);
601     for (CeedInt i=0; i<shape[0]; i++) {
602       for (CeedInt j=0; j<shape[1]; j++) {
603         for (CeedInt k=0; k<shape[2]; k++) {
604           xloc[((i*shape[1]+j)*shape[2]+k) + 0*len] = 1.*(irank[0]*melem[0]+i) /
605               (p[0]*melem[0]);
606           xloc[((i*shape[1]+j)*shape[2]+k) + 1*len] = 1.*(irank[1]*melem[1]+j) /
607               (p[1]*melem[1]);
608           xloc[((i*shape[1]+j)*shape[2]+k) + 2*len] = 1.*(irank[2]*melem[2]+k) /
609               (p[2]*melem[2]);
610         }
611       }
612     }
613     CeedVectorCreate(ceed, len*3, &xcoord);
614     CeedVectorSetArray(xcoord, CEED_MEM_HOST, CEED_OWN_POINTER, xloc);
615   }
616 
617   // Create the Q-function that builds the operator (i.e. computes its
618   // quadrature data) and set its context data
619   CeedQFunctionCreateInterior(ceed, 1, bpOptions[bpChoice].setup,
620                               bpOptions[bpChoice].setupfname, &qf_setup);
621   CeedQFunctionAddInput(qf_setup, "x", 3, CEED_EVAL_INTERP);
622   CeedQFunctionAddInput(qf_setup, "dx", 3, CEED_EVAL_GRAD);
623   CeedQFunctionAddInput(qf_setup, "weight", 1, CEED_EVAL_WEIGHT);
624   CeedQFunctionAddOutput(qf_setup, "rho", bpOptions[bpChoice].qdatasize,
625                          CEED_EVAL_NONE);
626   CeedQFunctionAddOutput(qf_setup, "true_soln", vscale, CEED_EVAL_NONE);
627   CeedQFunctionAddOutput(qf_setup, "rhs", vscale, CEED_EVAL_INTERP);
628 
629   // Set up PDE operator
630   CeedQFunctionCreateInterior(ceed, 1, bpOptions[bpChoice].apply,
631                               bpOptions[bpChoice].applyfname, &qf_apply);
632   // Add inputs and outputs
633   CeedQFunctionAddInput(qf_apply, "u", vscale, bpOptions[bpChoice].inmode);
634   CeedQFunctionAddInput(qf_apply, "rho", bpOptions[bpChoice].qdatasize,
635                         CEED_EVAL_NONE);
636   CeedQFunctionAddOutput(qf_apply, "v", vscale, bpOptions[bpChoice].outmode);
637 
638   // Create the error qfunction
639   CeedQFunctionCreateInterior(ceed, 1, bpOptions[bpChoice].error,
640                               bpOptions[bpChoice].errorfname, &qf_error);
641   CeedQFunctionAddInput(qf_error, "u", vscale, CEED_EVAL_INTERP);
642   CeedQFunctionAddInput(qf_error, "true_soln", vscale, CEED_EVAL_NONE);
643   CeedQFunctionAddOutput(qf_error, "error", vscale, CEED_EVAL_NONE);
644 
645   // Create the persistent vectors that will be needed in setup
646   CeedInt nqpts;
647   CeedBasisGetNumQuadraturePoints(basisu, &nqpts);
648   CeedVectorCreate(ceed, bpOptions[bpChoice].qdatasize*nelem*nqpts, &rho);
649   CeedVectorCreate(ceed, nelem*nqpts*vscale, &target);
650   CeedVectorCreate(ceed, lsize*vscale, &rhsceed);
651 
652   // Create the operator that builds the quadrature data for the ceed operator
653   CeedOperatorCreate(ceed, qf_setup, NULL, NULL, &op_setup);
654   CeedOperatorSetField(op_setup, "x", Erestrictx, CEED_NOTRANSPOSE,
655                        basisx, CEED_VECTOR_ACTIVE);
656   CeedOperatorSetField(op_setup, "dx", Erestrictx, CEED_NOTRANSPOSE,
657                        basisx, CEED_VECTOR_ACTIVE);
658   CeedOperatorSetField(op_setup, "weight", Erestrictxi, CEED_NOTRANSPOSE,
659                        basisx, CEED_VECTOR_NONE);
660   CeedOperatorSetField(op_setup, "rho", Erestrictqdi, CEED_NOTRANSPOSE,
661                        CEED_BASIS_COLLOCATED, CEED_VECTOR_ACTIVE);
662   CeedOperatorSetField(op_setup, "true_soln", Erestrictui, CEED_NOTRANSPOSE,
663                        CEED_BASIS_COLLOCATED, target);
664   CeedOperatorSetField(op_setup, "rhs", Erestrictu, CEED_TRANSPOSE,
665                        basisu, rhsceed);
666 
667   // Create the mass or diff operator
668   CeedOperatorCreate(ceed, qf_apply, NULL, NULL, &op_apply);
669   CeedOperatorSetField(op_apply, "u", Erestrictu, CEED_TRANSPOSE,
670                        basisu, CEED_VECTOR_ACTIVE);
671   CeedOperatorSetField(op_apply, "rho", Erestrictqdi, CEED_NOTRANSPOSE,
672                        CEED_BASIS_COLLOCATED, rho);
673   CeedOperatorSetField(op_apply, "v", Erestrictu, CEED_TRANSPOSE,
674                        basisu, CEED_VECTOR_ACTIVE);
675 
676   // Create the error operator
677   CeedOperatorCreate(ceed, qf_error, NULL, NULL, &op_error);
678   CeedOperatorSetField(op_error, "u", Erestrictu, CEED_TRANSPOSE,
679                        basisu, CEED_VECTOR_ACTIVE);
680   CeedOperatorSetField(op_error, "true_soln", Erestrictui, CEED_NOTRANSPOSE,
681                        CEED_BASIS_COLLOCATED, target);
682   CeedOperatorSetField(op_error, "error", Erestrictui, CEED_NOTRANSPOSE,
683                        CEED_BASIS_COLLOCATED, CEED_VECTOR_ACTIVE);
684 
685 
686   // Set up Mat
687   ierr = PetscMalloc1(1, &user); CHKERRQ(ierr);
688   user->comm = comm;
689   user->ltog = ltog;
690   if (bpChoice != CEED_BP1 && bpChoice != CEED_BP2) {
691     user->ltog0 = ltog0;
692     user->gtogD = gtogD;
693   }
694   user->Xloc = Xloc;
695   ierr = VecDuplicate(Xloc, &user->Yloc); CHKERRQ(ierr);
696   CeedVectorCreate(ceed, lsize*vscale, &user->xceed);
697   CeedVectorCreate(ceed, lsize*vscale, &user->yceed);
698   user->op = op_apply;
699   user->rho = rho;
700   user->ceed = ceed;
701 
702   ierr = MatCreateShell(comm, mnodes[0]*mnodes[1]*mnodes[2]*vscale,
703                         mnodes[0]*mnodes[1]*mnodes[2]*vscale,
704                         PETSC_DECIDE, PETSC_DECIDE, user, &mat); CHKERRQ(ierr);
705   if (bpChoice == CEED_BP1 || bpChoice == CEED_BP2) {
706     ierr = MatShellSetOperation(mat, MATOP_MULT, (void(*)(void))MatMult_Mass);
707     CHKERRQ(ierr);
708   } else {
709     ierr = MatShellSetOperation(mat, MATOP_MULT, (void(*)(void))MatMult_Diff);
710     CHKERRQ(ierr);
711   }
712   ierr = MatCreateVecs(mat, &rhs, NULL); CHKERRQ(ierr);
713 
714   // Get RHS vector
715   ierr = VecDuplicate(Xloc, &rhsloc); CHKERRQ(ierr);
716   ierr = VecZeroEntries(rhsloc); CHKERRQ(ierr);
717   ierr = VecGetArray(rhsloc, &r); CHKERRQ(ierr);
718   CeedVectorSetArray(rhsceed, CEED_MEM_HOST, CEED_USE_POINTER, r);
719 
720   // Setup rho, rhs, and target
721   CeedOperatorApply(op_setup, xcoord, rho, CEED_REQUEST_IMMEDIATE);
722   ierr = CeedVectorSyncArray(rhsceed, CEED_MEM_HOST); CHKERRQ(ierr);
723   CeedVectorDestroy(&xcoord);
724 
725   // Gather RHS
726   ierr = VecRestoreArray(rhsloc, &r); CHKERRQ(ierr);
727   ierr = VecZeroEntries(rhs); CHKERRQ(ierr);
728   ierr = VecScatterBegin(ltog, rhsloc, rhs, ADD_VALUES, SCATTER_FORWARD);
729   CHKERRQ(ierr);
730   ierr = VecScatterEnd(ltog, rhsloc, rhs, ADD_VALUES, SCATTER_FORWARD);
731   CHKERRQ(ierr);
732   CeedVectorDestroy(&rhsceed);
733 
734   ierr = KSPCreate(comm, &ksp); CHKERRQ(ierr);
735   {
736     PC pc;
737     ierr = KSPGetPC(ksp, &pc); CHKERRQ(ierr);
738     if (bpChoice == CEED_BP1 || bpChoice == CEED_BP2) {
739       ierr = PCSetType(pc, PCJACOBI); CHKERRQ(ierr);
740       ierr = PCJacobiSetType(pc, PC_JACOBI_ROWSUM); CHKERRQ(ierr);
741     } else {
742       ierr = PCSetType(pc, PCNONE); CHKERRQ(ierr);
743     }
744     ierr = KSPSetType(ksp, KSPCG); CHKERRQ(ierr);
745     ierr = KSPSetNormType(ksp, KSP_NORM_NATURAL); CHKERRQ(ierr);
746     ierr = KSPSetTolerances(ksp, 1e-10, PETSC_DEFAULT, PETSC_DEFAULT,
747                             PETSC_DEFAULT); CHKERRQ(ierr);
748   }
749   ierr = KSPSetFromOptions(ksp); CHKERRQ(ierr);
750   ierr = KSPSetOperators(ksp, mat, mat); CHKERRQ(ierr);
751   // First run, if benchmarking
752   if (benchmark_mode) {
753     ierr = KSPSetTolerances(ksp, 1e-10, PETSC_DEFAULT, PETSC_DEFAULT, 1);
754     CHKERRQ(ierr);
755     my_rt_start = MPI_Wtime();
756     ierr = KSPSolve(ksp, rhs, X); CHKERRQ(ierr);
757     my_rt = MPI_Wtime() - my_rt_start;
758     // Set maxits based on first iteration timing
759     if (my_rt > 0.02) {
760       ierr = KSPSetTolerances(ksp, 1e-10, PETSC_DEFAULT, PETSC_DEFAULT, 5);
761       CHKERRQ(ierr);
762     } else {
763       ierr = KSPSetTolerances(ksp, 1e-10, PETSC_DEFAULT, PETSC_DEFAULT, 20);
764       CHKERRQ(ierr);
765     }
766   }
767   // Timed solve
768   my_rt_start = MPI_Wtime();
769   ierr = KSPSolve(ksp, rhs, X); CHKERRQ(ierr);
770   my_rt = MPI_Wtime() - my_rt_start;
771   {
772     KSPType ksptype;
773     KSPConvergedReason reason;
774     PetscReal rnorm;
775     PetscInt its;
776     ierr = KSPGetType(ksp, &ksptype); CHKERRQ(ierr);
777     ierr = KSPGetConvergedReason(ksp, &reason); CHKERRQ(ierr);
778     ierr = KSPGetIterationNumber(ksp, &its); CHKERRQ(ierr);
779     ierr = KSPGetResidualNorm(ksp, &rnorm); CHKERRQ(ierr);
780     if (!test_mode || reason < 0 || rnorm > 1e-8) {
781       ierr = PetscPrintf(comm,
782                          "  KSP:\n"
783                          "    KSP Type                           : %s\n"
784                          "    KSP Convergence                    : %s\n"
785                          "    Total KSP Iterations               : %D\n"
786                          "    Final rnorm                        : %e\n",
787                          ksptype, KSPConvergedReasons[reason], its,
788                          (double)rnorm); CHKERRQ(ierr);
789     }
790     if (benchmark_mode && (!test_mode)) {
791       CeedInt gsize;
792       ierr = VecGetSize(X, &gsize); CHKERRQ(ierr);
793       MPI_Reduce(&my_rt, &rt_min, 1, MPI_DOUBLE, MPI_MIN, 0, comm);
794       MPI_Reduce(&my_rt, &rt_max, 1, MPI_DOUBLE, MPI_MAX, 0, comm);
795       ierr = PetscPrintf(comm,
796                          "  Performance:\n"
797                          "    CG Solve Time                      : %g (%g) sec\n"
798                          "    DoFs/Sec in CG                     : %g (%g) million\n",
799                          rt_max, rt_min, 1e-6*gsize*its/rt_max,
800                          1e-6*gsize*its/rt_min); CHKERRQ(ierr);
801     }
802   }
803 
804   {
805     PetscReal maxerror;
806     ierr = ComputeErrorMax(user, op_error, X, target, &maxerror); CHKERRQ(ierr);
807     PetscReal tol = (bpChoice == CEED_BP1 || bpChoice == CEED_BP2) ? 5e-3 : 5e-2;
808     if (!test_mode || maxerror > tol) {
809       ierr = PetscPrintf(comm,
810                          "    Pointwise Error (max)              : %e\n",
811                          (double)maxerror); CHKERRQ(ierr);
812     }
813   }
814 
815   if (write_solution) {
816     PetscViewer vtkviewersoln;
817 
818     ierr = PetscViewerCreate(comm, &vtkviewersoln); CHKERRQ(ierr);
819     ierr = PetscViewerSetType(vtkviewersoln, PETSCVIEWERVTK); CHKERRQ(ierr);
820     ierr = PetscViewerFileSetName(vtkviewersoln, "solution.vtk"); CHKERRQ(ierr);
821     ierr = VecView(X, vtkviewersoln); CHKERRQ(ierr);
822     ierr = PetscViewerDestroy(&vtkviewersoln); CHKERRQ(ierr);
823   }
824 
825   ierr = VecDestroy(&rhs); CHKERRQ(ierr);
826   ierr = VecDestroy(&rhsloc); CHKERRQ(ierr);
827   ierr = VecDestroy(&X); CHKERRQ(ierr);
828   ierr = VecDestroy(&user->Xloc); CHKERRQ(ierr);
829   ierr = VecDestroy(&user->Yloc); CHKERRQ(ierr);
830   ierr = VecScatterDestroy(&ltog); CHKERRQ(ierr);
831   ierr = VecScatterDestroy(&ltog0); CHKERRQ(ierr);
832   ierr = VecScatterDestroy(&gtogD); CHKERRQ(ierr);
833   ierr = MatDestroy(&mat); CHKERRQ(ierr);
834   ierr = KSPDestroy(&ksp); CHKERRQ(ierr);
835 
836   CeedVectorDestroy(&user->xceed);
837   CeedVectorDestroy(&user->yceed);
838   CeedVectorDestroy(&user->rho);
839   CeedVectorDestroy(&target);
840   CeedOperatorDestroy(&op_setup);
841   CeedOperatorDestroy(&op_apply);
842   CeedOperatorDestroy(&op_error);
843   CeedElemRestrictionDestroy(&Erestrictu);
844   CeedElemRestrictionDestroy(&Erestrictx);
845   CeedElemRestrictionDestroy(&Erestrictui);
846   CeedElemRestrictionDestroy(&Erestrictxi);
847   CeedElemRestrictionDestroy(&Erestrictqdi);
848   CeedQFunctionDestroy(&qf_setup);
849   CeedQFunctionDestroy(&qf_apply);
850   CeedQFunctionDestroy(&qf_error);
851   CeedBasisDestroy(&basisu);
852   CeedBasisDestroy(&basisx);
853   CeedDestroy(&ceed);
854   ierr = PetscFree(user); CHKERRQ(ierr);
855   return PetscFinalize();
856 }
857