Actual source code: bjkokkos.kokkos.cxx

  1: #define PETSC_SKIP_CXX_COMPLEX_FIX // Kokkos::complex does not need the PetscComplex fix

  3: #include <petsc/private/pcbjkokkosimpl.h>

  5: #include <petsc/private/kspimpl.h>
  6: #include <petscksp.h>
  7: #include <../src/mat/impls/aij/mpi/mpiaij.h>
  8: #include <../src/mat/impls/aij/seq/kokkos/aijkok.hpp>
  9: #include <petscsection.h>
 10: #include <petscdmcomposite.h>

 12: #include <../src/mat/impls/aij/seq/aij.h>
 13: #include <../src/mat/impls/aij/seq/kokkos/aijkok.hpp>

 15: #include <petscdevice_cupm.h>

 17: static PetscErrorCode PCBJKOKKOSCreateKSP_BJKOKKOS(PC pc)
 18: {
 19:   const char    *prefix;
 20:   PC_PCBJKOKKOS *jac = (PC_PCBJKOKKOS *)pc->data;
 21:   DM             dm;

 23:   PetscFunctionBegin;
 24:   PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc), &jac->ksp));
 25:   PetscCall(KSPSetNestLevel(jac->ksp, pc->kspnestlevel));
 26:   PetscCall(KSPSetErrorIfNotConverged(jac->ksp, pc->erroriffailure));
 27:   PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->ksp, (PetscObject)pc, 1));
 28:   PetscCall(PCGetOptionsPrefix(pc, &prefix));
 29:   PetscCall(KSPSetOptionsPrefix(jac->ksp, prefix));
 30:   PetscCall(KSPAppendOptionsPrefix(jac->ksp, "pc_bjkokkos_"));
 31:   PetscCall(PCGetDM(pc, &dm));
 32:   if (dm) {
 33:     PetscCall(KSPSetDM(jac->ksp, dm));
 34:     PetscCall(KSPSetDMActive(jac->ksp, PETSC_FALSE));
 35:   }
 36:   jac->reason       = PETSC_FALSE;
 37:   jac->monitor      = PETSC_FALSE;
 38:   jac->batch_target = 0;
 39:   jac->rank_target  = 0;
 40:   jac->nsolves_team = 1;
 41:   jac->ksp->max_it  = 50; // this is really for GMRES w/o restarts
 42:   PetscFunctionReturn(PETSC_SUCCESS);
 43: }

 45: // y <-- Ax
 46: KOKKOS_INLINE_FUNCTION PetscErrorCode MatMult(const team_member team, const PetscInt *glb_Aai, const PetscInt *glb_Aaj, const PetscScalar *glb_Aaa, const PetscInt *r, const PetscInt *ic, const PetscInt start, const PetscInt end, const PetscScalar *x_loc, PetscScalar *y_loc)
 47: {
 48:   Kokkos::parallel_for(Kokkos::TeamThreadRange(team, start, end), [=](const int rowb) {
 49:     int                rowa = ic[rowb];
 50:     int                n    = glb_Aai[rowa + 1] - glb_Aai[rowa];
 51:     const PetscInt    *aj   = glb_Aaj + glb_Aai[rowa]; // global
 52:     const PetscScalar *aa   = glb_Aaa + glb_Aai[rowa];
 53:     PetscScalar        sum;
 54:     Kokkos::parallel_reduce(Kokkos::ThreadVectorRange(team, n), [=](const int i, PetscScalar &lsum) { lsum += aa[i] * x_loc[r[aj[i]] - start]; }, sum);
 55:     Kokkos::single(Kokkos::PerThread(team), [=]() { y_loc[rowb - start] = sum; });
 56:   });
 57:   team.team_barrier();
 58:   return PETSC_SUCCESS;
 59: }

 61: // temp buffer per thread with reduction at end?
 62: KOKKOS_INLINE_FUNCTION PetscErrorCode MatMultTranspose(const team_member team, const PetscInt *glb_Aai, const PetscInt *glb_Aaj, const PetscScalar *glb_Aaa, const PetscInt *r, const PetscInt *ic, const PetscInt start, const PetscInt end, const PetscScalar *x_loc, PetscScalar *y_loc)
 63: {
 64:   Kokkos::parallel_for(Kokkos::TeamVectorRange(team, end - start), [=](int i) { y_loc[i] = 0; });
 65:   team.team_barrier();
 66:   Kokkos::parallel_for(Kokkos::TeamThreadRange(team, start, end), [=](const int rowb) {
 67:     int                rowa = ic[rowb];
 68:     int                n    = glb_Aai[rowa + 1] - glb_Aai[rowa];
 69:     const PetscInt    *aj   = glb_Aaj + glb_Aai[rowa]; // global
 70:     const PetscScalar *aa   = glb_Aaa + glb_Aai[rowa];
 71:     const PetscScalar  xx   = x_loc[rowb - start]; // rowb = ic[rowa] = ic[r[rowb]]
 72:     Kokkos::parallel_for(Kokkos::ThreadVectorRange(team, n), [=](const int &i) {
 73:       PetscScalar val = aa[i] * xx;
 74:       Kokkos::atomic_fetch_add(&y_loc[r[aj[i]] - start], val);
 75:     });
 76:   });
 77:   team.team_barrier();
 78:   return PETSC_SUCCESS;
 79: }

 81: typedef struct Batch_MetaData_TAG {
 82:   PetscInt           flops;
 83:   PetscInt           its;
 84:   KSPConvergedReason reason;
 85: } Batch_MetaData;

 87: // Solve A(BB^-1)x = y with TFQMR. Right preconditioned to get un-preconditioned residual
 88: static KOKKOS_INLINE_FUNCTION PetscErrorCode BJSolve_TFQMR(const team_member team, const PetscInt *glb_Aai, const PetscInt *glb_Aaj, const PetscScalar *glb_Aaa, const PetscInt *r, const PetscInt *ic, PetscScalar *work_space_global, const int stride_global, const int nShareVec, PetscScalar *work_space_shared, const int stride_shared, PetscReal rtol, PetscReal atol, PetscReal dtol, PetscInt maxit, Batch_MetaData *metad, const PetscInt start, const PetscInt end, const PetscScalar glb_idiag[], const PetscScalar *glb_b, PetscScalar *glb_x, bool monitor)
 89: {
 90:   using Kokkos::parallel_for;
 91:   using Kokkos::parallel_reduce;
 92:   int                Nblk = end - start, it, m, stride = stride_shared, idx = 0;
 93:   PetscReal          dp, dpold, w, dpest, tau, psi, cm, r0;
 94:   const PetscScalar *Diag = &glb_idiag[start];
 95:   PetscScalar       *ptr  = work_space_shared, rho, rhoold, a, s, b, eta, etaold, psiold, cf, dpi;

 97:   if (idx++ == nShareVec) {
 98:     ptr    = work_space_global;
 99:     stride = stride_global;
100:   }
101:   PetscScalar *XX = ptr;
102:   ptr += stride;
103:   if (idx++ == nShareVec) {
104:     ptr    = work_space_global;
105:     stride = stride_global;
106:   }
107:   PetscScalar *R = ptr;
108:   ptr += stride;
109:   if (idx++ == nShareVec) {
110:     ptr    = work_space_global;
111:     stride = stride_global;
112:   }
113:   PetscScalar *RP = ptr;
114:   ptr += stride;
115:   if (idx++ == nShareVec) {
116:     ptr    = work_space_global;
117:     stride = stride_global;
118:   }
119:   PetscScalar *V = ptr;
120:   ptr += stride;
121:   if (idx++ == nShareVec) {
122:     ptr    = work_space_global;
123:     stride = stride_global;
124:   }
125:   PetscScalar *T = ptr;
126:   ptr += stride;
127:   if (idx++ == nShareVec) {
128:     ptr    = work_space_global;
129:     stride = stride_global;
130:   }
131:   PetscScalar *Q = ptr;
132:   ptr += stride;
133:   if (idx++ == nShareVec) {
134:     ptr    = work_space_global;
135:     stride = stride_global;
136:   }
137:   PetscScalar *P = ptr;
138:   ptr += stride;
139:   if (idx++ == nShareVec) {
140:     ptr    = work_space_global;
141:     stride = stride_global;
142:   }
143:   PetscScalar *U = ptr;
144:   ptr += stride;
145:   if (idx++ == nShareVec) {
146:     ptr    = work_space_global;
147:     stride = stride_global;
148:   }
149:   PetscScalar *D = ptr;
150:   ptr += stride;
151:   if (idx++ == nShareVec) {
152:     ptr    = work_space_global;
153:     stride = stride_global;
154:   }
155:   PetscScalar *AUQ = V;

157:   // init: get b, zero x
158:   parallel_for(Kokkos::TeamVectorRange(team, start, end), [=](int rowb) {
159:     int rowa         = ic[rowb];
160:     R[rowb - start]  = glb_b[rowa];
161:     XX[rowb - start] = 0;
162:   });
163:   team.team_barrier();
164:   parallel_reduce(Kokkos::TeamVectorRange(team, Nblk), [=](const int idx, PetscScalar &lsum) { lsum += R[idx] * PetscConj(R[idx]); }, dpi);
165:   team.team_barrier();
166:   r0 = dp = PetscSqrtReal(PetscRealPart(dpi));
167:   // diagnostics
168: #if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_SYCL)
169:   if (monitor) Kokkos::single(Kokkos::PerTeam(team), [=]() { printf("%3d KSP Residual norm %14.12e\n", 0, (double)dp); });
170: #endif
171:   if (dp < atol) {
172:     metad->reason = KSP_CONVERGED_ATOL_NORMAL_EQUATIONS;
173:     it            = 0;
174:     goto done;
175:   }
176:   if (0 == maxit) {
177:     metad->reason = KSP_CONVERGED_ITS;
178:     it            = 0;
179:     goto done;
180:   }

182:   /* Make the initial Rp = R */
183:   parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) { RP[idx] = R[idx]; });
184:   team.team_barrier();
185:   /* Set the initial conditions */
186:   etaold = 0.0;
187:   psiold = 0.0;
188:   tau    = dp;
189:   dpold  = dp;

191:   /* rhoold = (r,rp)     */
192:   parallel_reduce(Kokkos::TeamVectorRange(team, Nblk), [=](const int idx, PetscScalar &dot) { dot += R[idx] * PetscConj(RP[idx]); }, rhoold);
193:   team.team_barrier();
194:   parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) {
195:     U[idx] = R[idx];
196:     P[idx] = R[idx];
197:     T[idx] = Diag[idx] * P[idx];
198:     D[idx] = 0;
199:   });
200:   team.team_barrier();
201:   static_cast<void>(MatMult(team, glb_Aai, glb_Aaj, glb_Aaa, r, ic, start, end, T, V));

203:   it = 0;
204:   do {
205:     /* s <- (v,rp)          */
206:     parallel_reduce(Kokkos::TeamVectorRange(team, Nblk), [=](const int idx, PetscScalar &dot) { dot += V[idx] * PetscConj(RP[idx]); }, s);
207:     team.team_barrier();
208:     if (s == 0) {
209:       metad->reason = KSP_CONVERGED_HAPPY_BREAKDOWN;
210:       goto done;
211:     }
212:     a = rhoold / s; /* a <- rho / s         */
213:     /* q <- u - a v    VecWAXPY(w,alpha,x,y): w = alpha x + y.     */
214:     /* t <- u + q           */
215:     parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) {
216:       Q[idx] = U[idx] - a * V[idx];
217:       T[idx] = U[idx] + Q[idx];
218:     });
219:     team.team_barrier();
220:     // KSP_PCApplyBAorAB
221:     parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) { T[idx] = Diag[idx] * T[idx]; });
222:     team.team_barrier();
223:     static_cast<void>(MatMult(team, glb_Aai, glb_Aaj, glb_Aaa, r, ic, start, end, T, AUQ));
224:     /* r <- r - a K (u + q) */
225:     parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) { R[idx] = R[idx] - a * AUQ[idx]; });
226:     team.team_barrier();
227:     parallel_reduce(Kokkos::TeamVectorRange(team, Nblk), [=](const int idx, PetscScalar &lsum) { lsum += R[idx] * PetscConj(R[idx]); }, dpi);
228:     team.team_barrier();
229:     dp = PetscSqrtReal(PetscRealPart(dpi));
230:     for (m = 0; m < 2; m++) {
231:       if (!m) w = PetscSqrtReal(dp * dpold);
232:       else w = dp;
233:       psi = w / tau;
234:       cm  = 1.0 / PetscSqrtReal(1.0 + psi * psi);
235:       tau = tau * psi * cm;
236:       eta = cm * cm * a;
237:       cf  = psiold * psiold * etaold / a;
238:       if (!m) {
239:         /* D = U + cf D */
240:         parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) { D[idx] = U[idx] + cf * D[idx]; });
241:       } else {
242:         /* D = Q + cf D */
243:         parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) { D[idx] = Q[idx] + cf * D[idx]; });
244:       }
245:       team.team_barrier();
246:       parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) { XX[idx] = XX[idx] + eta * D[idx]; });
247:       team.team_barrier();
248:       dpest = PetscSqrtReal(2 * it + m + 2.0) * tau;
249: #if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_SYCL)
250:       if (monitor && m == 1) Kokkos::single(Kokkos::PerTeam(team), [=]() { printf("%3d KSP Residual norm %14.12e\n", it + 1, (double)dpest); });
251: #endif
252:       if (dpest < atol) {
253:         metad->reason = KSP_CONVERGED_ATOL_NORMAL_EQUATIONS;
254:         goto done;
255:       }
256:       if (dpest / r0 < rtol) {
257:         metad->reason = KSP_CONVERGED_RTOL_NORMAL_EQUATIONS;
258:         goto done;
259:       }
260: #if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_SYCL)
261:       if (dpest / r0 > dtol) {
262:         metad->reason = KSP_DIVERGED_DTOL;
263:         Kokkos::single(Kokkos::PerTeam(team), [=]() { printf("ERROR block %d diverged: %d it, res=%e, r_0=%e\n", team.league_rank(), it, dpest, r0); });
264:         goto done;
265:       }
266: #else
267:       if (dpest / r0 > dtol) {
268:         metad->reason = KSP_DIVERGED_DTOL;
269:         goto done;
270:       }
271: #endif
272:       if (it + 1 == maxit) {
273:         metad->reason = KSP_CONVERGED_ITS;
274: #if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_SYCL)
275:         Kokkos::single(Kokkos::PerTeam(team), [=]() { printf("ERROR block %d diverged: TFQMR %d:%d it, res=%e, r_0=%e r_res=%e\n", team.league_rank(), it, m, dpest, r0, dpest / r0); });
276: #endif
277:         goto done;
278:       }
279:       etaold = eta;
280:       psiold = psi;
281:     }

283:     /* rho <- (r,rp)       */
284:     parallel_reduce(Kokkos::TeamVectorRange(team, Nblk), [=](const int idx, PetscScalar &dot) { dot += R[idx] * PetscConj(RP[idx]); }, rho);
285:     team.team_barrier();
286:     if (rho == 0) {
287:       metad->reason = KSP_CONVERGED_HAPPY_BREAKDOWN;
288:       goto done;
289:     }
290:     b = rho / rhoold; /* b <- rho / rhoold   */
291:     /* u <- r + b q        */
292:     /* p <- u + b(q + b p) */
293:     parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) {
294:       U[idx] = R[idx] + b * Q[idx];
295:       Q[idx] = Q[idx] + b * P[idx];
296:       P[idx] = U[idx] + b * Q[idx];
297:     });
298:     /* v <- K p  */
299:     team.team_barrier();
300:     parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) { T[idx] = Diag[idx] * P[idx]; });
301:     team.team_barrier();
302:     static_cast<void>(MatMult(team, glb_Aai, glb_Aaj, glb_Aaa, r, ic, start, end, T, V));

304:     rhoold = rho;
305:     dpold  = dp;

307:     it++;
308:   } while (it < maxit);
309: done:
310:   // KSPUnwindPreconditioner
311:   parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) { XX[idx] = Diag[idx] * XX[idx]; });
312:   team.team_barrier();
313:   // put x into Plex order
314:   parallel_for(Kokkos::TeamVectorRange(team, start, end), [=](int rowb) {
315:     int rowa    = ic[rowb];
316:     glb_x[rowa] = XX[rowb - start];
317:   });
318:   metad->its = it;
319:   if (1) {
320:     int nnz;
321:     parallel_reduce(Kokkos::TeamVectorRange(team, start, end), [=](const int idx, int &lsum) { lsum += (glb_Aai[idx + 1] - glb_Aai[idx]); }, nnz);
322:     metad->flops = 2 * (metad->its * (10 * Nblk + 2 * nnz) + 5 * Nblk);
323:   } else {
324:     metad->flops = 2 * (metad->its * (10 * Nblk + 2 * 50 * Nblk) + 5 * Nblk); // guess
325:   }
326:   return PETSC_SUCCESS;
327: }

329: // Solve Ax = y with biCG
330: static KOKKOS_INLINE_FUNCTION PetscErrorCode BJSolve_BICG(const team_member team, const PetscInt *glb_Aai, const PetscInt *glb_Aaj, const PetscScalar *glb_Aaa, const PetscInt *r, const PetscInt *ic, PetscScalar *work_space_global, const int stride_global, const int nShareVec, PetscScalar *work_space_shared, const int stride_shared, PetscReal rtol, PetscReal atol, PetscReal dtol, PetscInt maxit, Batch_MetaData *metad, const PetscInt start, const PetscInt end, const PetscScalar glb_idiag[], const PetscScalar *glb_b, PetscScalar *glb_x, bool monitor)
331: {
332:   using Kokkos::parallel_for;
333:   using Kokkos::parallel_reduce;
334:   int                Nblk = end - start, it, stride = stride_shared, idx = 0; // start in shared mem
335:   PetscReal          dp, r0;
336:   const PetscScalar *Di  = &glb_idiag[start];
337:   PetscScalar       *ptr = work_space_shared, dpi, a = 1.0, beta, betaold = 1.0, t1, t2;

339:   if (idx++ == nShareVec) {
340:     ptr    = work_space_global;
341:     stride = stride_global;
342:   }
343:   PetscScalar *XX = ptr;
344:   ptr += stride;
345:   if (idx++ == nShareVec) {
346:     ptr    = work_space_global;
347:     stride = stride_global;
348:   }
349:   PetscScalar *Rl = ptr;
350:   ptr += stride;
351:   if (idx++ == nShareVec) {
352:     ptr    = work_space_global;
353:     stride = stride_global;
354:   }
355:   PetscScalar *Zl = ptr;
356:   ptr += stride;
357:   if (idx++ == nShareVec) {
358:     ptr    = work_space_global;
359:     stride = stride_global;
360:   }
361:   PetscScalar *Pl = ptr;
362:   ptr += stride;
363:   if (idx++ == nShareVec) {
364:     ptr    = work_space_global;
365:     stride = stride_global;
366:   }
367:   PetscScalar *Rr = ptr;
368:   ptr += stride;
369:   if (idx++ == nShareVec) {
370:     ptr    = work_space_global;
371:     stride = stride_global;
372:   }
373:   PetscScalar *Zr = ptr;
374:   ptr += stride;
375:   if (idx++ == nShareVec) {
376:     ptr    = work_space_global;
377:     stride = stride_global;
378:   }
379:   PetscScalar *Pr = ptr;
380:   ptr += stride;

382:   /*     r <- b (x is 0) */
383:   parallel_for(Kokkos::TeamVectorRange(team, start, end), [=](int rowb) {
384:     int rowa         = ic[rowb];
385:     Rl[rowb - start] = Rr[rowb - start] = glb_b[rowa];
386:     XX[rowb - start]                    = 0;
387:   });
388:   team.team_barrier();
389:   /*     z <- Br         */
390:   parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) {
391:     Zr[idx] = Di[idx] * Rr[idx];
392:     Zl[idx] = Di[idx] * Rl[idx];
393:   });
394:   team.team_barrier();
395:   /*    dp <- r'*r       */
396:   parallel_reduce(Kokkos::TeamVectorRange(team, Nblk), [=](const int idx, PetscScalar &lsum) { lsum += Rr[idx] * PetscConj(Rr[idx]); }, dpi);
397:   team.team_barrier();
398:   r0 = dp = PetscSqrtReal(PetscRealPart(dpi));
399: #if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_SYCL)
400:   if (monitor) Kokkos::single(Kokkos::PerTeam(team), [=]() { printf("%3d KSP Residual norm %14.12e\n", 0, (double)dp); });
401: #endif
402:   if (dp < atol) {
403:     metad->reason = KSP_CONVERGED_ATOL_NORMAL_EQUATIONS;
404:     it            = 0;
405:     goto done;
406:   }
407:   if (0 == maxit) {
408:     metad->reason = KSP_CONVERGED_ITS;
409:     it            = 0;
410:     goto done;
411:   }

413:   it = 0;
414:   do {
415:     /*     beta <- r'z     */
416:     parallel_reduce(Kokkos::TeamVectorRange(team, Nblk), [=](const int idx, PetscScalar &dot) { dot += Zr[idx] * PetscConj(Rl[idx]); }, beta);
417:     team.team_barrier();
418: #if PCBJKOKKOS_VERBOSE_LEVEL >= 6
419:   #if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_SYCL)
420:     Kokkos::single(Kokkos::PerTeam(team), [=]() { printf("%7d beta = Z.R = %22.14e \n", i, (double)beta); });
421:   #endif
422: #endif
423:     if (beta == 0.0) {
424:       metad->reason = KSP_CONVERGED_HAPPY_BREAKDOWN;
425:       goto done;
426:     }
427:     if (it == 0) {
428:       /*     p <- z          */
429:       parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) {
430:         Pr[idx] = Zr[idx];
431:         Pl[idx] = Zl[idx];
432:       });
433:     } else {
434:       t1 = beta / betaold;
435:       /*     p <- z + b* p   */
436:       t2 = PetscConj(t1);
437:       parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) {
438:         Pr[idx] = t1 * Pr[idx] + Zr[idx];
439:         Pl[idx] = t2 * Pl[idx] + Zl[idx];
440:       });
441:     }
442:     team.team_barrier();
443:     betaold = beta;
444:     /*     z <- Kp         */
445:     static_cast<void>(MatMult(team, glb_Aai, glb_Aaj, glb_Aaa, r, ic, start, end, Pr, Zr));
446:     static_cast<void>(MatMultTranspose(team, glb_Aai, glb_Aaj, glb_Aaa, r, ic, start, end, Pl, Zl));
447:     /*     dpi <- z'p      */
448:     parallel_reduce(Kokkos::TeamVectorRange(team, Nblk), [=](const int idx, PetscScalar &lsum) { lsum += Zr[idx] * PetscConj(Pl[idx]); }, dpi);
449:     team.team_barrier();
450:     if (dpi == 0) {
451:       metad->reason = KSP_CONVERGED_HAPPY_BREAKDOWN;
452:       goto done;
453:     }
454:     //
455:     a  = beta / dpi; /*     a = beta/p'z    */
456:     t1 = -a;
457:     t2 = PetscConj(t1);
458:     /*     x <- x + ap     */
459:     parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) {
460:       XX[idx] = XX[idx] + a * Pr[idx];
461:       Rr[idx] = Rr[idx] + t1 * Zr[idx];
462:       Rl[idx] = Rl[idx] + t2 * Zl[idx];
463:     });
464:     team.team_barrier();
465:     team.team_barrier();
466:     /*    dp <- r'*r       */
467:     parallel_reduce(Kokkos::TeamVectorRange(team, Nblk), [=](const int idx, PetscScalar &lsum) { lsum += Rr[idx] * PetscConj(Rr[idx]); }, dpi);
468:     team.team_barrier();
469:     dp = PetscSqrtReal(PetscRealPart(dpi));
470: #if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_SYCL)
471:     if (monitor) Kokkos::single(Kokkos::PerTeam(team), [=]() { printf("%3d KSP Residual norm %14.12e\n", it + 1, (double)dp); });
472: #endif
473:     if (dp < atol) {
474:       metad->reason = KSP_CONVERGED_ATOL_NORMAL_EQUATIONS;
475:       goto done;
476:     }
477:     if (dp / r0 < rtol) {
478:       metad->reason = KSP_CONVERGED_RTOL_NORMAL_EQUATIONS;
479:       goto done;
480:     }
481: #if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_SYCL)
482:     if (dp / r0 > dtol) {
483:       metad->reason = KSP_DIVERGED_DTOL;
484:       Kokkos::single(Kokkos::PerTeam(team), [=]() { printf("ERROR block %d diverged: %d it, res=%e, r_0=%e (BICG does this)\n", team.league_rank(), it, dp, r0); });
485:       goto done;
486:     }
487: #else
488:     if (dp / r0 > dtol) {
489:       metad->reason = KSP_DIVERGED_DTOL;
490:       goto done;
491:     }
492: #endif
493:     if (it + 1 == maxit) {
494:       metad->reason = KSP_CONVERGED_ITS; // don't worry about hitting max iterations
495: #if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_SYCL)
496:       Kokkos::single(Kokkos::PerTeam(team), [=]() { printf("ERROR block %d diverged: BICG %d it, res=%e, r_0=%e r_res=%e\n", team.league_rank(), it, dp, r0, dp / r0); });
497: #endif
498:       goto done;
499:     }
500:     /* z <- Br  */
501:     parallel_for(Kokkos::TeamVectorRange(team, Nblk), [=](int idx) {
502:       Zr[idx] = Di[idx] * Rr[idx];
503:       Zl[idx] = Di[idx] * Rl[idx];
504:     });

506:     it++;
507:   } while (it < maxit);
508: done:
509:   // put x back into Plex order
510:   parallel_for(Kokkos::TeamVectorRange(team, start, end), [=](int rowb) {
511:     int rowa    = ic[rowb];
512:     glb_x[rowa] = XX[rowb - start];
513:   });
514:   metad->its = it;
515:   if (1) {
516:     int nnz;
517:     parallel_reduce(Kokkos::TeamVectorRange(team, start, end), [=](const int idx, int &lsum) { lsum += (glb_Aai[idx + 1] - glb_Aai[idx]); }, nnz);
518:     metad->flops = 2 * (metad->its * (10 * Nblk + 2 * nnz) + 5 * Nblk);
519:   } else {
520:     metad->flops = 2 * (metad->its * (10 * Nblk + 2 * 50 * Nblk) + 5 * Nblk); // guess
521:   }
522:   return PETSC_SUCCESS;
523: }

525: // KSP solver solve Ax = b; xout is output, bin is input
526: static PetscErrorCode PCApply_BJKOKKOS(PC pc, Vec bin, Vec xout)
527: {
528:   PC_PCBJKOKKOS *jac = (PC_PCBJKOKKOS *)pc->data;
529:   Mat            A = pc->pmat, Aseq = A;
530:   PetscMPIInt    rank;

532:   PetscFunctionBegin;
533:   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)A), &rank));
534:   if (!A->spptr) Aseq = ((Mat_MPIAIJ *)A->data)->A; // MPI
535:   PetscCall(MatSeqAIJKokkosSyncDevice(Aseq));
536:   {
537:     PetscInt           maxit = jac->ksp->max_it;
538:     const PetscInt     conc = Kokkos::DefaultExecutionSpace().concurrency(), openmp = !!(conc < 1000), team_size = (openmp == 0 && PCBJKOKKOS_VEC_SIZE != 1) ? PCBJKOKKOS_TEAM_SIZE : 1;
539:     const PetscInt     nwork = jac->nwork, nBlk = jac->nBlocks;
540:     PetscScalar       *glb_xdata = NULL, *dummy;
541:     PetscReal          rtol = jac->ksp->rtol, atol = jac->ksp->abstol, dtol = jac->ksp->divtol;
542:     const PetscScalar *glb_idiag = jac->d_idiag_k->data(), *glb_bdata = NULL;
543:     const PetscInt    *glb_Aai, *glb_Aaj, *d_bid_eqOffset = jac->d_bid_eqOffset_k->data();
544:     const PetscScalar *glb_Aaa;
545:     const PetscInt    *d_isicol = jac->d_isicol_k->data(), *d_isrow = jac->d_isrow_k->data();
546:     PCFailedReason     pcreason;
547:     KSPIndex           ksp_type_idx = jac->ksp_type_idx;
548:     PetscMemType       mtype;
549:     PetscContainer     container;
550:     PetscInt           batch_sz;                // the number of repeated DMs, [DM_e_1, DM_e_2, DM_e_batch_sz, DM_i_1, ...]
551:     VecScatter         plex_batch = NULL;       // not used
552:     Vec                bvec;                    // a copy of b for scatter (just alias to bin now)
553:     PetscBool          monitor  = jac->monitor; // captured
554:     PetscInt           view_bid = jac->batch_target;
555:     MatInfo            info;

557:     PetscCall(MatSeqAIJGetCSRAndMemType(Aseq, &glb_Aai, &glb_Aaj, &dummy, &mtype));
558:     jac->max_nits = 0;
559:     glb_Aaa       = dummy;
560:     if (jac->rank_target != rank) view_bid = -1; // turn off all but one process
561:     PetscCall(MatGetInfo(A, MAT_LOCAL, &info));
562:     // get field major is to map plex IO to/from block/field major
563:     PetscCall(PetscObjectQuery((PetscObject)A, "plex_batch_is", (PetscObject *)&container));
564:     if (container) {
565:       PetscCall(VecDuplicate(bin, &bvec));
566:       PetscCall(PetscContainerGetPointer(container, (void **)&plex_batch));
567:       PetscCall(VecScatterBegin(plex_batch, bin, bvec, INSERT_VALUES, SCATTER_FORWARD));
568:       PetscCall(VecScatterEnd(plex_batch, bin, bvec, INSERT_VALUES, SCATTER_FORWARD));
569:       SETERRQ(PetscObjectComm((PetscObject)A), PETSC_ERR_USER, "No plex_batch_is -- require NO field major ordering for now");
570:     } else {
571:       bvec = bin;
572:     }
573:     // get x
574:     PetscCall(VecGetArrayAndMemType(xout, &glb_xdata, &mtype));
575: #if defined(PETSC_HAVE_CUDA)
576:     PetscCheck(PetscMemTypeDevice(mtype), PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "No GPU data for x %d != %d", static_cast<int>(mtype), static_cast<int>(PETSC_MEMTYPE_DEVICE));
577: #endif
578:     PetscCall(VecGetArrayReadAndMemType(bvec, &glb_bdata, &mtype));
579: #if defined(PETSC_HAVE_CUDA)
580:     PetscCheck(PetscMemTypeDevice(mtype), PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "No GPU data for b");
581: #endif
582:     // get batch size
583:     PetscCall(PetscObjectQuery((PetscObject)A, "batch size", (PetscObject *)&container));
584:     if (container) {
585:       PetscInt *pNf = NULL;
586:       PetscCall(PetscContainerGetPointer(container, (void **)&pNf));
587:       batch_sz = *pNf; // number of times to repeat the DMs
588:     } else batch_sz = 1;
589:     PetscCheck(nBlk % batch_sz == 0, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "batch_sz = %" PetscInt_FMT ", nBlk = %" PetscInt_FMT, batch_sz, nBlk);
590:     if (ksp_type_idx == BATCH_KSP_GMRESKK_IDX) {
591:       // KK solver - move PETSc data into Kokkos Views, setup solver, solve, move data out of Kokkos, process metadata (convergence tests, etc.)
592: #if defined(PETSC_HAVE_KOKKOS_KERNELS_BATCH)
593:       PetscCall(PCApply_BJKOKKOSKERNELS(pc, glb_bdata, glb_xdata, glb_Aai, glb_Aaj, glb_Aaa, team_size, info, batch_sz, &pcreason));
594: #else
595:       PetscCheck(ksp_type_idx != BATCH_KSP_GMRESKK_IDX, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Type: BATCH_KSP_GMRES not supported for complex");
596: #endif
597:     } else { // Kokkos Krylov
598:       using scr_mem_t    = Kokkos::DefaultExecutionSpace::scratch_memory_space;
599:       using vect2D_scr_t = Kokkos::View<PetscScalar **, Kokkos::LayoutLeft, scr_mem_t>;
600:       Kokkos::View<Batch_MetaData *, Kokkos::DefaultExecutionSpace> d_metadata("solver meta data", nBlk);
601:       int                                                           stride_shared, stride_global, global_buff_words;
602:       d_bid_eqOffset = jac->d_bid_eqOffset_k->data();
603:       // solve each block independently
604:       int scr_bytes_team_shared = 0, nShareVec = 0, nGlobBVec = 0;
605:       if (jac->const_block_size) { // use shared memory for work vectors only if constant block size - TODO: test efficiency loss
606:         size_t      maximum_shared_mem_size = 64000;
607:         PetscDevice device;
608:         PetscCall(PetscDeviceGetDefault_Internal(&device));
609:         PetscCall(PetscDeviceGetAttribute(device, PETSC_DEVICE_ATTR_SIZE_T_SHARED_MEM_PER_BLOCK, &maximum_shared_mem_size));
610:         stride_shared = jac->const_block_size;                                                   // captured
611:         nShareVec     = maximum_shared_mem_size / (jac->const_block_size * sizeof(PetscScalar)); // integer floor, number of vectors that fit in shared
612:         if (nShareVec > nwork) nShareVec = nwork;
613:         else nGlobBVec = nwork - nShareVec;
614:         global_buff_words     = jac->n * nGlobBVec;
615:         scr_bytes_team_shared = jac->const_block_size * nShareVec * sizeof(PetscScalar);
616:       } else {
617:         scr_bytes_team_shared = 0;
618:         stride_shared         = 0;
619:         global_buff_words     = jac->n * nwork;
620:         nGlobBVec             = nwork; // not needed == fix
621:       }
622:       stride_global = jac->n; // captured
623: #if defined(PETSC_HAVE_CUDA)
624:       nvtxRangePushA("batch-kokkos-solve");
625: #endif
626:       Kokkos::View<PetscScalar *, Kokkos::DefaultExecutionSpace> d_work_vecs_k("workvectors", global_buff_words); // global work vectors
627: #if PCBJKOKKOS_VERBOSE_LEVEL > 1
628:       PetscCall(PetscInfo(pc, "\tn = %d. %d shared bytes/team, %d global mem bytes, rtol=%e, num blocks %d, team_size=%d, %d vector threads, %d shared vectors, %d global vectors\n", (int)jac->n, scr_bytes_team_shared, global_buff_words, rtol, (int)nBlk, (int)team_size, PCBJKOKKOS_VEC_SIZE, nShareVec, nGlobBVec));
629: #endif
630:       PetscScalar *d_work_vecs = d_work_vecs_k.data();
631:       Kokkos::parallel_for(
632:         "Solve", Kokkos::TeamPolicy<Kokkos::LaunchBounds<256, 4>>(nBlk, team_size, PCBJKOKKOS_VEC_SIZE).set_scratch_size(PCBJKOKKOS_SHARED_LEVEL, Kokkos::PerTeam(scr_bytes_team_shared)), KOKKOS_LAMBDA(const team_member team) {
633:           const int    blkID = team.league_rank(), start = d_bid_eqOffset[blkID], end = d_bid_eqOffset[blkID + 1];
634:           vect2D_scr_t work_vecs_shared(team.team_scratch(PCBJKOKKOS_SHARED_LEVEL), end - start, nShareVec);
635:           PetscScalar *work_buff_shared = work_vecs_shared.data();
636:           PetscScalar *work_buff_global = &d_work_vecs[start]; // start inc'ed in
637:           bool         print            = monitor && (blkID == view_bid);
638:           switch (ksp_type_idx) {
639:           case BATCH_KSP_BICG_IDX:
640:             static_cast<void>(BJSolve_BICG(team, glb_Aai, glb_Aaj, glb_Aaa, d_isrow, d_isicol, work_buff_global, stride_global, nShareVec, work_buff_shared, stride_shared, rtol, atol, dtol, maxit, &d_metadata[blkID], start, end, glb_idiag, glb_bdata, glb_xdata, print));
641:             break;
642:           case BATCH_KSP_TFQMR_IDX:
643:             static_cast<void>(BJSolve_TFQMR(team, glb_Aai, glb_Aaj, glb_Aaa, d_isrow, d_isicol, work_buff_global, stride_global, nShareVec, work_buff_shared, stride_shared, rtol, atol, dtol, maxit, &d_metadata[blkID], start, end, glb_idiag, glb_bdata, glb_xdata, print));
644:             break;
645:           default:
646: #if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_SYCL)
647:             printf("Unknown KSP type %d\n", ksp_type_idx);
648: #else
649:             /* void */;
650: #endif
651:           }
652:         });
653:       Kokkos::fence();
654: #if defined(PETSC_HAVE_CUDA)
655:       nvtxRangePop();
656:       nvtxRangePushA("Post-solve-metadata");
657: #endif
658:       auto h_metadata = Kokkos::create_mirror(Kokkos::HostSpace::memory_space(), d_metadata);
659:       Kokkos::deep_copy(h_metadata, d_metadata);
660:       PetscInt max_nnit = -1;
661: #if PCBJKOKKOS_VERBOSE_LEVEL > 1
662:       PetscInt mbid = 0;
663: #endif
664:       int in[2], out[2];
665:       if (jac->reason) { // -pc_bjkokkos_ksp_converged_reason
666: #if PCBJKOKKOS_VERBOSE_LEVEL >= 3
667:   #if PCBJKOKKOS_VERBOSE_LEVEL >= 4
668:         PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Iterations\n"));
669:   #endif
670:         // assume species major
671:   #if PCBJKOKKOS_VERBOSE_LEVEL == 3
672:         if (batch_sz != 1) PetscCall(PetscPrintf(PetscObjectComm((PetscObject)A), "%s: max iterations per species:", ksp_type_idx == BATCH_KSP_BICG_IDX ? "bicg" : "tfqmr"));
673:         else PetscCall(PetscPrintf(PetscObjectComm((PetscObject)A), "    Linear solve converged due to %s iterations ", ksp_type_idx == BATCH_KSP_BICG_IDX ? "bicg" : "tfqmr"));
674:   #endif
675:         for (PetscInt dmIdx = 0, head = 0, s = 0; dmIdx < jac->num_dms; dmIdx += batch_sz) {
676:           for (PetscInt f = 0, idx = head; f < jac->dm_Nf[dmIdx]; f++, idx++, s++) {
677:             for (int bid = 0; bid < batch_sz; bid++) {
678:   #if PCBJKOKKOS_VERBOSE_LEVEL >= 4
679:               jac->max_nits += h_metadata[idx + bid * jac->dm_Nf[dmIdx]].its; // report total number of iterations with high verbose
680:               if (h_metadata[idx + bid * jac->dm_Nf[dmIdx]].its > max_nnit) {
681:                 max_nnit = h_metadata[idx + bid * jac->dm_Nf[dmIdx]].its;
682:                 mbid     = bid;
683:               }
684:   #else
685:               if (h_metadata[idx + bid * jac->dm_Nf[dmIdx]].its > max_nnit) {
686:                 jac->max_nits = max_nnit = h_metadata[idx + bid * jac->dm_Nf[dmIdx]].its;
687:                 mbid                     = bid;
688:               }
689:   #endif
690:             }
691:   #if PCBJKOKKOS_VERBOSE_LEVEL >= 4
692:             PetscCall(PetscPrintf(PetscObjectComm((PetscObject)A), "%2" PetscInt_FMT ":", s));
693:             for (int bid = 0; bid < batch_sz; bid++) PetscCall(PetscPrintf(PetscObjectComm((PetscObject)A), "%3" PetscInt_FMT " ", h_metadata[idx + bid * jac->dm_Nf[dmIdx]].its));
694:             PetscCall(PetscPrintf(PetscObjectComm((PetscObject)A), "\n"));
695:   #else // == 3
696:             PetscCall(PetscPrintf(PetscObjectComm((PetscObject)A), "%3" PetscInt_FMT " ", max_nnit));
697:   #endif
698:           }
699:           head += batch_sz * jac->dm_Nf[dmIdx];
700:         }
701:   #if PCBJKOKKOS_VERBOSE_LEVEL == 3
702:         PetscCall(PetscPrintf(PetscObjectComm((PetscObject)A), "\n"));
703:   #endif
704: #endif
705:         if (max_nnit == -1) { // < 3
706:           for (int blkID = 0; blkID < nBlk; blkID++) {
707:             if (h_metadata[blkID].its > max_nnit) {
708:               jac->max_nits = max_nnit = h_metadata[blkID].its;
709: #if PCBJKOKKOS_VERBOSE_LEVEL > 1
710:               mbid = blkID;
711: #endif
712:             }
713:           }
714:         }
715:         in[0] = max_nnit;
716:         in[1] = rank;
717:         PetscCallMPI(MPIU_Allreduce(in, out, 1, MPI_2INT, MPI_MAXLOC, PetscObjectComm((PetscObject)A)));
718: #if PCBJKOKKOS_VERBOSE_LEVEL > 1
719:         if (0 == rank) {
720:           if (batch_sz != 1)
721:             PetscCall(PetscPrintf(PETSC_COMM_SELF, "[%d] Linear solve converged due to %s iterations %d (max), on block %" PetscInt_FMT ", species %" PetscInt_FMT " (max)\n", out[1], KSPConvergedReasons[h_metadata[mbid].reason], out[0], mbid % batch_sz, mbid / batch_sz));
722:           else PetscCall(PetscPrintf(PETSC_COMM_SELF, "[%d] Linear solve converged due to %s iterations %d (max), on block %" PetscInt_FMT "\n", out[1], KSPConvergedReasons[h_metadata[mbid].reason], out[0], mbid));
723:         }
724: #endif
725:       }
726:       for (int blkID = 0; blkID < nBlk; blkID++) {
727:         PetscCall(PetscLogGpuFlops((PetscLogDouble)h_metadata[blkID].flops));
728:         PetscCheck(h_metadata[blkID].reason >= 0 || !jac->ksp->errorifnotconverged, PetscObjectComm((PetscObject)pc), PETSC_ERR_CONV_FAILED, "ERROR reason=%s, its=%" PetscInt_FMT ". species %" PetscInt_FMT ", batch %" PetscInt_FMT,
729:                    KSPConvergedReasons[h_metadata[blkID].reason], h_metadata[blkID].its, blkID / batch_sz, blkID % batch_sz);
730:       }
731:       {
732:         int errsum;
733:         Kokkos::parallel_reduce(
734:           nBlk,
735:           KOKKOS_LAMBDA(const int idx, int &lsum) {
736:             if (d_metadata[idx].reason < 0) ++lsum;
737:           },
738:           errsum);
739:         pcreason = errsum ? PC_SUBPC_ERROR : PC_NOERROR;
740:         if (!errsum && !jac->max_nits) { // set max its to give back to top KSP
741:           for (int blkID = 0; blkID < nBlk; blkID++) {
742:             if (h_metadata[blkID].its > jac->max_nits) jac->max_nits = h_metadata[blkID].its;
743:           }
744:         } else if (errsum) {
745:           PetscCall(PetscPrintf(PETSC_COMM_SELF, "[%d] ERROR Kokkos batch solver did not converge in all solves\n", (int)rank));
746:         }
747:       }
748: #if defined(PETSC_HAVE_CUDA)
749:       nvtxRangePop();
750: #endif
751:     } // end of Kokkos (not Kernels) solvers block
752:     PetscCall(VecRestoreArrayAndMemType(xout, &glb_xdata));
753:     PetscCall(VecRestoreArrayReadAndMemType(bvec, &glb_bdata));
754:     PetscCall(PCSetFailedReason(pc, pcreason));
755:     // map back to Plex space - not used
756:     if (plex_batch) {
757:       PetscCall(VecCopy(xout, bvec));
758:       PetscCall(VecScatterBegin(plex_batch, bvec, xout, INSERT_VALUES, SCATTER_REVERSE));
759:       PetscCall(VecScatterEnd(plex_batch, bvec, xout, INSERT_VALUES, SCATTER_REVERSE));
760:       PetscCall(VecDestroy(&bvec));
761:     }
762:   }
763:   PetscFunctionReturn(PETSC_SUCCESS);
764: }

766: static PetscErrorCode PCSetUp_BJKOKKOS(PC pc)
767: {
768:   PC_PCBJKOKKOS *jac = (PC_PCBJKOKKOS *)pc->data;
769:   Mat            A = pc->pmat, Aseq = A; // use filtered block matrix, really "P"
770:   PetscBool      flg;

772:   PetscFunctionBegin;
773:   PetscCheck(A, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "No matrix - A is used above");
774:   PetscCall(PetscObjectTypeCompareAny((PetscObject)A, &flg, MATSEQAIJKOKKOS, MATMPIAIJKOKKOS, MATAIJKOKKOS, ""));
775:   PetscCheck(flg, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "must use '-[dm_]mat_type aijkokkos -[dm_]vec_type kokkos' for -pc_type bjkokkos");
776:   if (!A->spptr) Aseq = ((Mat_MPIAIJ *)A->data)->A; // MPI
777:   PetscCall(MatSeqAIJKokkosSyncDevice(Aseq));
778:   {
779:     PetscInt    Istart, Iend;
780:     PetscMPIInt rank;
781:     PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)A), &rank));
782:     PetscCall(MatGetOwnershipRange(A, &Istart, &Iend));
783:     if (!jac->vec_diag) {
784:       Vec     *subX = NULL;
785:       DM       pack, *subDM = NULL;
786:       PetscInt nDMs, n, *block_sizes = NULL;
787:       IS       isrow, isicol;
788:       { // Permute the matrix to get a block diagonal system: d_isrow_k, d_isicol_k
789:         MatOrderingType rtype;
790:         const PetscInt *rowindices, *icolindices;
791:         rtype = MATORDERINGRCM;
792:         // get permutation. And invert. should we convert to local indices?
793:         PetscCall(MatGetOrdering(Aseq, rtype, &isrow, &isicol)); // only seems to work for seq matrix
794:         PetscCall(ISDestroy(&isrow));
795:         PetscCall(ISInvertPermutation(isicol, PETSC_DECIDE, &isrow)); // THIS IS BACKWARD -- isrow is inverse
796:         // if (rank==1) PetscCall(ISView(isicol, PETSC_VIEWER_STDOUT_SELF));
797:         if (0) {
798:           Mat mat_block_order; // debug
799:           PetscCall(ISShift(isicol, Istart, isicol));
800:           PetscCall(MatCreateSubMatrix(A, isicol, isicol, MAT_INITIAL_MATRIX, &mat_block_order));
801:           PetscCall(ISShift(isicol, -Istart, isicol));
802:           PetscCall(MatViewFromOptions(mat_block_order, NULL, "-ksp_batch_reorder_view"));
803:           PetscCall(MatDestroy(&mat_block_order));
804:         }
805:         PetscCall(ISGetIndices(isrow, &rowindices)); // local idx
806:         PetscCall(ISGetIndices(isicol, &icolindices));
807:         const Kokkos::View<PetscInt *, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_isrow_k((PetscInt *)rowindices, A->rmap->n);
808:         const Kokkos::View<PetscInt *, Kokkos::HostSpace, Kokkos::MemoryTraits<Kokkos::Unmanaged>> h_isicol_k((PetscInt *)icolindices, A->rmap->n);
809:         jac->d_isrow_k  = new Kokkos::View<PetscInt *>(Kokkos::create_mirror(DefaultMemorySpace(), h_isrow_k));
810:         jac->d_isicol_k = new Kokkos::View<PetscInt *>(Kokkos::create_mirror(DefaultMemorySpace(), h_isicol_k));
811:         Kokkos::deep_copy(*jac->d_isrow_k, h_isrow_k);
812:         Kokkos::deep_copy(*jac->d_isicol_k, h_isicol_k);
813:         PetscCall(ISRestoreIndices(isrow, &rowindices));
814:         PetscCall(ISRestoreIndices(isicol, &icolindices));
815:         // if (rank==1) PetscCall(ISView(isicol, PETSC_VIEWER_STDOUT_SELF));
816:       }
817:       // get block sizes & allocate vec_diag
818:       PetscCall(PCGetDM(pc, &pack));
819:       if (pack) {
820:         PetscCall(PetscObjectTypeCompare((PetscObject)pack, DMCOMPOSITE, &flg));
821:         if (flg) {
822:           PetscCall(DMCompositeGetNumberDM(pack, &nDMs));
823:           PetscCall(DMCreateGlobalVector(pack, &jac->vec_diag));
824:         } else pack = NULL; // flag for no DM
825:       }
826:       if (!jac->vec_diag) { // get 'nDMs' and sizes 'block_sizes' w/o DMComposite. TODO: User could provide ISs
827:         PetscInt        bsrt, bend, ncols, ntot = 0;
828:         const PetscInt *colsA, nloc = Iend - Istart;
829:         const PetscInt *rowindices, *icolindices;
830:         PetscCall(PetscMalloc1(nloc, &block_sizes)); // very inefficient, to big
831:         PetscCall(ISGetIndices(isrow, &rowindices));
832:         PetscCall(ISGetIndices(isicol, &icolindices));
833:         nDMs = 0;
834:         bsrt = 0;
835:         bend = 1;
836:         for (PetscInt row_B = 0; row_B < nloc; row_B++) { // for all rows in block diagonal space
837:           PetscInt rowA = icolindices[row_B], minj = PETSC_INT_MAX, maxj = 0;
838:           //PetscCall(PetscPrintf(PETSC_COMM_SELF, "\t[%d] rowA = %d\n",rank,rowA));
839:           PetscCall(MatGetRow(Aseq, rowA, &ncols, &colsA, NULL)); // not sorted in permutation
840:           PetscCheck(ncols, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Empty row not supported: %" PetscInt_FMT, row_B);
841:           for (PetscInt colj = 0; colj < ncols; colj++) {
842:             PetscInt colB = rowindices[colsA[colj]]; // use local idx
843:             //PetscCall(PetscPrintf(PETSC_COMM_SELF, "\t\t[%d] colB = %d\n",rank,colB));
844:             PetscCheck(colB >= 0 && colB < nloc, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "colB < 0: %" PetscInt_FMT, colB);
845:             if (colB > maxj) maxj = colB;
846:             if (colB < minj) minj = colB;
847:           }
848:           PetscCall(MatRestoreRow(Aseq, rowA, &ncols, &colsA, NULL));
849:           if (minj >= bend) { // first column is > max of last block -- new block or last block
850:             //PetscCall(PetscPrintf(PetscObjectComm((PetscObject)A), "\t\t finish block %d, N loc = %d (%d,%d)\n", nDMs+1, bend - bsrt,bsrt,bend));
851:             block_sizes[nDMs] = bend - bsrt;
852:             ntot += block_sizes[nDMs];
853:             PetscCheck(minj == bend, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "minj != bend: %" PetscInt_FMT " != %" PetscInt_FMT, minj, bend);
854:             bsrt = bend;
855:             bend++; // start with size 1 in new block
856:             nDMs++;
857:           }
858:           if (maxj + 1 > bend) bend = maxj + 1;
859:           PetscCheck(minj >= bsrt || row_B == Iend - 1, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "%" PetscInt_FMT ") minj < bsrt: %" PetscInt_FMT " != %" PetscInt_FMT, rowA, minj, bsrt);
860:           //PetscCall(PetscPrintf(PETSC_COMM_SELF, "[%d] %d) row %d.%d) cols %d : %d ; bsrt = %d, bend = %d\n",rank,row_B,nDMs,rowA,minj,maxj,bsrt,bend));
861:         }
862:         // do last block
863:         //PetscCall(PetscPrintf(PETSC_COMM_SELF, "\t\t\t [%d] finish block %d, N loc = %d (%d,%d)\n", rank, nDMs+1, bend - bsrt,bsrt,bend));
864:         block_sizes[nDMs] = bend - bsrt;
865:         ntot += block_sizes[nDMs];
866:         nDMs++;
867:         // cleanup
868:         PetscCheck(ntot == nloc, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "n total != n local: %" PetscInt_FMT " != %" PetscInt_FMT, ntot, nloc);
869:         PetscCall(ISRestoreIndices(isrow, &rowindices));
870:         PetscCall(ISRestoreIndices(isicol, &icolindices));
871:         PetscCall(PetscRealloc(sizeof(PetscInt) * nDMs, &block_sizes));
872:         PetscCall(MatCreateVecs(A, &jac->vec_diag, NULL));
873:         PetscCall(PetscInfo(pc, "Setup Matrix based meta data (not DMComposite not attached to PC) %" PetscInt_FMT " sub domains\n", nDMs));
874:       }
875:       PetscCall(ISDestroy(&isrow));
876:       PetscCall(ISDestroy(&isicol));
877:       jac->num_dms = nDMs;
878:       PetscCall(VecGetLocalSize(jac->vec_diag, &n));
879:       jac->n         = n;
880:       jac->d_idiag_k = new Kokkos::View<PetscScalar *, Kokkos::LayoutRight>("idiag", n);
881:       // options
882:       PetscCall(PCBJKOKKOSCreateKSP_BJKOKKOS(pc));
883:       PetscCall(KSPSetFromOptions(jac->ksp));
884:       PetscCall(PetscObjectTypeCompareAny((PetscObject)jac->ksp, &flg, KSPBICG, ""));
885:       if (flg) {
886:         jac->ksp_type_idx = BATCH_KSP_BICG_IDX;
887:         jac->nwork        = 7;
888:       } else {
889:         PetscCall(PetscObjectTypeCompareAny((PetscObject)jac->ksp, &flg, KSPTFQMR, ""));
890:         if (flg) {
891:           jac->ksp_type_idx = BATCH_KSP_TFQMR_IDX;
892:           jac->nwork        = 10;
893:         } else {
894: #if defined(PETSC_HAVE_KOKKOS_KERNELS_BATCH)
895:           PetscCall(PetscObjectTypeCompareAny((PetscObject)jac->ksp, &flg, KSPGMRES, ""));
896:           PetscCheck(flg, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "Unsupported batch ksp type");
897:           jac->ksp_type_idx = BATCH_KSP_GMRESKK_IDX;
898:           jac->nwork        = 0;
899: #else
900:           KSPType ksptype;
901:           PetscCall(KSPGetType(jac->ksp, &ksptype));
902:           PetscCheck(flg, PetscObjectComm((PetscObject)pc), PETSC_ERR_ARG_WRONG, "Type: %s not supported in complex", ksptype);
903: #endif
904:         }
905:       }
906:       PetscOptionsBegin(PetscObjectComm((PetscObject)jac->ksp), ((PetscObject)jac->ksp)->prefix, "Options for Kokkos batch solver", "none");
907:       PetscCall(PetscOptionsBool("-ksp_converged_reason", "", "bjkokkos.kokkos.cxx.c", jac->reason, &jac->reason, NULL));
908:       PetscCall(PetscOptionsBool("-ksp_monitor", "", "bjkokkos.kokkos.cxx.c", jac->monitor, &jac->monitor, NULL));
909:       PetscCall(PetscOptionsInt("-ksp_batch_target", "", "bjkokkos.kokkos.cxx.c", jac->batch_target, &jac->batch_target, NULL));
910:       PetscCall(PetscOptionsInt("-ksp_rank_target", "", "bjkokkos.kokkos.cxx.c", jac->rank_target, &jac->rank_target, NULL));
911:       PetscCall(PetscOptionsInt("-ksp_batch_nsolves_team", "", "bjkokkos.kokkos.cxx.c", jac->nsolves_team, &jac->nsolves_team, NULL));
912:       PetscCheck(jac->batch_target < jac->num_dms, PETSC_COMM_WORLD, PETSC_ERR_ARG_WRONG, "-ksp_batch_target (%" PetscInt_FMT ") >= number of DMs (%" PetscInt_FMT ")", jac->batch_target, jac->num_dms);
913:       PetscOptionsEnd();
914:       // get blocks - jac->d_bid_eqOffset_k
915:       if (pack) {
916:         PetscCall(PetscMalloc(sizeof(*subX) * nDMs, &subX));
917:         PetscCall(PetscMalloc(sizeof(*subDM) * nDMs, &subDM));
918:       }
919:       PetscCall(PetscMalloc(sizeof(*jac->dm_Nf) * nDMs, &jac->dm_Nf));
920:       PetscCall(PetscInfo(pc, "Have %" PetscInt_FMT " blocks, n=%" PetscInt_FMT " rtol=%g type = %s\n", nDMs, n, (double)jac->ksp->rtol, ((PetscObject)jac->ksp)->type_name));
921:       if (pack) PetscCall(DMCompositeGetEntriesArray(pack, subDM));
922:       jac->nBlocks = 0;
923:       for (PetscInt ii = 0; ii < nDMs; ii++) {
924:         PetscInt Nf;
925:         if (subDM) {
926:           DM           dm = subDM[ii];
927:           PetscSection section;
928:           PetscCall(DMGetLocalSection(dm, &section));
929:           PetscCall(PetscSectionGetNumFields(section, &Nf));
930:         } else Nf = 1;
931:         jac->nBlocks += Nf;
932: #if PCBJKOKKOS_VERBOSE_LEVEL <= 2
933:         if (ii == 0) PetscCall(PetscInfo(pc, "%" PetscInt_FMT ") %" PetscInt_FMT " blocks (%" PetscInt_FMT " total)\n", ii, Nf, jac->nBlocks));
934: #else
935:         PetscCall(PetscInfo(pc, "%" PetscInt_FMT ") %" PetscInt_FMT " blocks (%" PetscInt_FMT " total)\n", ii, Nf, jac->nBlocks));
936: #endif
937:         jac->dm_Nf[ii] = Nf;
938:       }
939:       { // d_bid_eqOffset_k
940:         Kokkos::View<PetscInt *, Kokkos::LayoutRight, Kokkos::HostSpace> h_block_offsets("block_offsets", jac->nBlocks + 1);
941:         if (pack) PetscCall(DMCompositeGetAccessArray(pack, jac->vec_diag, nDMs, NULL, subX));
942:         h_block_offsets[0]    = 0;
943:         jac->const_block_size = -1;
944:         for (PetscInt ii = 0, idx = 0; ii < nDMs; ii++) {
945:           PetscInt nloc, nblk;
946:           if (pack) PetscCall(VecGetSize(subX[ii], &nloc));
947:           else nloc = block_sizes[ii];
948:           nblk = nloc / jac->dm_Nf[ii];
949:           PetscCheck(nloc % jac->dm_Nf[ii] == 0, PetscObjectComm((PetscObject)pc), PETSC_ERR_USER, "nloc%%jac->dm_Nf[ii] (%" PetscInt_FMT ") != 0 DMs", nloc % jac->dm_Nf[ii]);
950:           for (PetscInt jj = 0; jj < jac->dm_Nf[ii]; jj++, idx++) {
951:             h_block_offsets[idx + 1] = h_block_offsets[idx] + nblk;
952: #if PCBJKOKKOS_VERBOSE_LEVEL <= 2
953:             if (idx == 0) PetscCall(PetscInfo(pc, "Add first of %" PetscInt_FMT " blocks with %" PetscInt_FMT " equations\n", jac->nBlocks, nblk));
954: #else
955:             PetscCall(PetscInfo(pc, "\t%" PetscInt_FMT ") Add block with %" PetscInt_FMT " equations of %" PetscInt_FMT "\n", idx + 1, nblk, jac->nBlocks));
956: #endif
957:             if (jac->const_block_size == -1) jac->const_block_size = nblk;
958:             else if (jac->const_block_size > 0 && jac->const_block_size != nblk) jac->const_block_size = 0;
959:           }
960:         }
961:         if (pack) {
962:           PetscCall(DMCompositeRestoreAccessArray(pack, jac->vec_diag, jac->nBlocks, NULL, subX));
963:           PetscCall(PetscFree(subX));
964:           PetscCall(PetscFree(subDM));
965:         }
966:         jac->d_bid_eqOffset_k = new Kokkos::View<PetscInt *, Kokkos::LayoutRight>(Kokkos::create_mirror(Kokkos::DefaultExecutionSpace::memory_space(), h_block_offsets));
967:         Kokkos::deep_copy(*jac->d_bid_eqOffset_k, h_block_offsets);
968:       }
969:       if (!pack) PetscCall(PetscFree(block_sizes));
970:     }
971:     { // get jac->d_idiag_k (PC setup),
972:       const PetscInt    *d_ai, *d_aj;
973:       const PetscScalar *d_aa;
974:       const PetscInt     conc = Kokkos::DefaultExecutionSpace().concurrency(), openmp = !!(conc < 1000), team_size = (openmp == 0 && PCBJKOKKOS_VEC_SIZE != 1) ? PCBJKOKKOS_TEAM_SIZE : 1;
975:       const PetscInt    *d_bid_eqOffset = jac->d_bid_eqOffset_k->data(), *r = jac->d_isrow_k->data(), *ic = jac->d_isicol_k->data();
976:       PetscScalar       *d_idiag = jac->d_idiag_k->data(), *dummy;
977:       PetscMemType       mtype;
978:       PetscCall(MatSeqAIJGetCSRAndMemType(Aseq, &d_ai, &d_aj, &dummy, &mtype));
979:       d_aa = dummy;
980:       Kokkos::parallel_for(
981:         "Diag", Kokkos::TeamPolicy<>(jac->nBlocks, team_size, PCBJKOKKOS_VEC_SIZE), KOKKOS_LAMBDA(const team_member team) {
982:           const PetscInt blkID = team.league_rank();
983:           Kokkos::parallel_for(Kokkos::TeamThreadRange(team, d_bid_eqOffset[blkID], d_bid_eqOffset[blkID + 1]), [=](const int rowb) {
984:             const PetscInt     rowa = ic[rowb], ai = d_ai[rowa], *aj = d_aj + ai; // grab original data
985:             const PetscScalar *aa   = d_aa + ai;
986:             const PetscInt     nrow = d_ai[rowa + 1] - ai;
987:             int                found;
988:             Kokkos::parallel_reduce(
989:               Kokkos::ThreadVectorRange(team, nrow),
990:               [=](const int &j, int &count) {
991:                 const PetscInt colb = r[aj[j]];
992:                 if (colb == rowb) {
993:                   d_idiag[rowb] = 1. / aa[j];
994:                   count++;
995:                 }
996:               },
997:               found);
998: #if defined(PETSC_USE_DEBUG) && !defined(PETSC_HAVE_SYCL)
999:             if (found != 1) Kokkos::single(Kokkos::PerThread(team), [=]() { printf("ERRORrow %d) found = %d\n", rowb, found); });
1000: #endif
1001:           });
1002:         });
1003:     }
1004:   }
1005:   PetscFunctionReturn(PETSC_SUCCESS);
1006: }

1008: /* Default destroy, if it has never been setup */
1009: static PetscErrorCode PCReset_BJKOKKOS(PC pc)
1010: {
1011:   PC_PCBJKOKKOS *jac = (PC_PCBJKOKKOS *)pc->data;

1013:   PetscFunctionBegin;
1014:   PetscCall(KSPDestroy(&jac->ksp));
1015:   PetscCall(VecDestroy(&jac->vec_diag));
1016:   if (jac->d_bid_eqOffset_k) delete jac->d_bid_eqOffset_k;
1017:   if (jac->d_idiag_k) delete jac->d_idiag_k;
1018:   if (jac->d_isrow_k) delete jac->d_isrow_k;
1019:   if (jac->d_isicol_k) delete jac->d_isicol_k;
1020:   jac->d_bid_eqOffset_k = NULL;
1021:   jac->d_idiag_k        = NULL;
1022:   jac->d_isrow_k        = NULL;
1023:   jac->d_isicol_k       = NULL;
1024:   PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCBJKOKKOSGetKSP_C", NULL)); // not published now (causes configure errors)
1025:   PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCBJKOKKOSSetKSP_C", NULL));
1026:   PetscCall(PetscFree(jac->dm_Nf));
1027:   jac->dm_Nf = NULL;
1028:   if (jac->rowOffsets) delete jac->rowOffsets;
1029:   if (jac->colIndices) delete jac->colIndices;
1030:   if (jac->batch_b) delete jac->batch_b;
1031:   if (jac->batch_x) delete jac->batch_x;
1032:   if (jac->batch_values) delete jac->batch_values;
1033:   jac->rowOffsets   = NULL;
1034:   jac->colIndices   = NULL;
1035:   jac->batch_b      = NULL;
1036:   jac->batch_x      = NULL;
1037:   jac->batch_values = NULL;
1038:   PetscFunctionReturn(PETSC_SUCCESS);
1039: }

1041: static PetscErrorCode PCDestroy_BJKOKKOS(PC pc)
1042: {
1043:   PetscFunctionBegin;
1044:   PetscCall(PCReset_BJKOKKOS(pc));
1045:   PetscCall(PetscFree(pc->data));
1046:   PetscFunctionReturn(PETSC_SUCCESS);
1047: }

1049: static PetscErrorCode PCView_BJKOKKOS(PC pc, PetscViewer viewer)
1050: {
1051:   PC_PCBJKOKKOS *jac = (PC_PCBJKOKKOS *)pc->data;
1052:   PetscBool      isascii;

1054:   PetscFunctionBegin;
1055:   if (!jac->ksp) PetscCall(PCBJKOKKOSCreateKSP_BJKOKKOS(pc));
1056:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
1057:   if (isascii) {
1058:     PetscCall(PetscViewerASCIIPrintf(viewer, "  Batched device linear solver: Krylov (KSP) method with Jacobi preconditioning\n"));
1059:     PetscCall(PetscViewerASCIIPrintf(viewer, "\t\tnwork = %" PetscInt_FMT ", rel tol = %e, abs tol = %e, div tol = %e, max it =%" PetscInt_FMT ", type = %s\n", jac->nwork, jac->ksp->rtol, jac->ksp->abstol, jac->ksp->divtol, jac->ksp->max_it,
1060:                                      ((PetscObject)jac->ksp)->type_name));
1061:   }
1062:   PetscFunctionReturn(PETSC_SUCCESS);
1063: }

1065: static PetscErrorCode PCSetFromOptions_BJKOKKOS(PC pc, PetscOptionItems PetscOptionsObject)
1066: {
1067:   PetscFunctionBegin;
1068:   PetscOptionsHeadBegin(PetscOptionsObject, "PC BJKOKKOS options");
1069:   PetscOptionsHeadEnd();
1070:   PetscFunctionReturn(PETSC_SUCCESS);
1071: }

1073: static PetscErrorCode PCBJKOKKOSSetKSP_BJKOKKOS(PC pc, KSP ksp)
1074: {
1075:   PC_PCBJKOKKOS *jac = (PC_PCBJKOKKOS *)pc->data;

1077:   PetscFunctionBegin;
1078:   PetscCall(PetscObjectReference((PetscObject)ksp));
1079:   PetscCall(KSPDestroy(&jac->ksp));
1080:   jac->ksp = ksp;
1081:   PetscFunctionReturn(PETSC_SUCCESS);
1082: }

1084: /*@
1085:   PCBJKOKKOSSetKSP - Sets the `KSP` context for `PCBJKOKKOS`

1087:   Collective

1089:   Input Parameters:
1090: + pc  - the `PCBJKOKKOS` preconditioner context
1091: - ksp - the `KSP` solver

1093:   Level: advanced

1095:   Notes:
1096:   The `PC` and the `KSP` must have the same communicator

1098:   If the `PC` is not `PCBJKOKKOS` this function returns without doing anything

1100: .seealso: [](ch_ksp), `PCBJKOKKOSGetKSP()`, `PCBJKOKKOS`
1101: @*/
1102: PetscErrorCode PCBJKOKKOSSetKSP(PC pc, KSP ksp)
1103: {
1104:   PetscFunctionBegin;
1107:   PetscCheckSameComm(pc, 1, ksp, 2);
1108:   PetscTryMethod(pc, "PCBJKOKKOSSetKSP_C", (PC, KSP), (pc, ksp));
1109:   PetscFunctionReturn(PETSC_SUCCESS);
1110: }

1112: static PetscErrorCode PCBJKOKKOSGetKSP_BJKOKKOS(PC pc, KSP *ksp)
1113: {
1114:   PC_PCBJKOKKOS *jac = (PC_PCBJKOKKOS *)pc->data;

1116:   PetscFunctionBegin;
1117:   if (!jac->ksp) PetscCall(PCBJKOKKOSCreateKSP_BJKOKKOS(pc));
1118:   *ksp = jac->ksp;
1119:   PetscFunctionReturn(PETSC_SUCCESS);
1120: }

1122: /*@
1123:   PCBJKOKKOSGetKSP - Gets the `KSP` context for the `PCBJKOKKOS` preconditioner

1125:   Not Collective but `KSP` returned is parallel if `PC` was parallel

1127:   Input Parameter:
1128: . pc - the preconditioner context

1130:   Output Parameter:
1131: . ksp - the `KSP` solver

1133:   Level: advanced

1135:   Notes:
1136:   You must call `KSPSetUp()` before calling `PCBJKOKKOSGetKSP()`.

1138:   If the `PC` is not a `PCBJKOKKOS` object it raises an error

1140: .seealso: [](ch_ksp), `PCBJKOKKOS`, `PCBJKOKKOSSetKSP()`
1141: @*/
1142: PetscErrorCode PCBJKOKKOSGetKSP(PC pc, KSP *ksp)
1143: {
1144:   PetscFunctionBegin;
1146:   PetscAssertPointer(ksp, 2);
1147:   PetscUseMethod(pc, "PCBJKOKKOSGetKSP_C", (PC, KSP *), (pc, ksp));
1148:   PetscFunctionReturn(PETSC_SUCCESS);
1149: }

1151: static PetscErrorCode PCPostSolve_BJKOKKOS(PC pc, KSP ksp, Vec b, Vec x)
1152: {
1153:   PC_PCBJKOKKOS *jac = (PC_PCBJKOKKOS *)pc->data;

1155:   PetscFunctionBegin;
1157:   ksp->its = jac->max_nits;
1158:   PetscFunctionReturn(PETSC_SUCCESS);
1159: }

1161: static PetscErrorCode PCPreSolve_BJKOKKOS(PC pc, KSP ksp, Vec b, Vec x)
1162: {
1163:   PC_PCBJKOKKOS *jac = (PC_PCBJKOKKOS *)pc->data;

1165:   PetscFunctionBegin;
1167:   jac->ksp->errorifnotconverged = ksp->errorifnotconverged;
1168:   PetscFunctionReturn(PETSC_SUCCESS);
1169: }

1171: /*MC
1172:      PCBJKOKKOS - A batched Krylov/block Jacobi solver that runs a solve of each diagaonl block of a block diagonal `MATSEQAIJ` in a Kokkos thread group

1174:    Options Database Key:
1175: .  -pc_bjkokkos_ - options prefix for its `KSP` options

1177:    Level: intermediate

1179:    Note:
1180:    For use with `-ksp_type preonly` to bypass any computation on the CPU

1182:    Developer Notes:
1183:    The entire Krylov (TFQMR or BICG) with diagonal preconditioning for each block of a block diagnaol matrix runs in a Kokkos thread group (eg, one block per SM on NVIDIA). It supports taking a non-block diagonal matrix but this is not tested. One should create an explicit block diagonal matrix and use that as the matrix for constructing the preconditioner in the outer `KSP` solver. Variable block size are supported and tested in src/ts/utils/dmplexlandau/tutorials/ex[1|2].c

1185: .seealso: [](ch_ksp), `PCCreate()`, `PCSetType()`, `PCType`, `PC`, `PCBJACOBI`,
1186:           `PCSHELL`, `PCCOMPOSITE`, `PCSetUseAmat()`, `PCBJKOKKOSGetKSP()`
1187: M*/

1189: PETSC_EXTERN PetscErrorCode PCCreate_BJKOKKOS(PC pc)
1190: {
1191:   PC_PCBJKOKKOS *jac;

1193:   PetscFunctionBegin;
1194:   PetscCall(PetscNew(&jac));
1195:   pc->data = (void *)jac;

1197:   jac->ksp              = NULL;
1198:   jac->vec_diag         = NULL;
1199:   jac->d_bid_eqOffset_k = NULL;
1200:   jac->d_idiag_k        = NULL;
1201:   jac->d_isrow_k        = NULL;
1202:   jac->d_isicol_k       = NULL;
1203:   jac->nBlocks          = 1;
1204:   jac->max_nits         = 0;

1206:   PetscCall(PetscMemzero(pc->ops, sizeof(struct _PCOps)));
1207:   pc->ops->apply          = PCApply_BJKOKKOS;
1208:   pc->ops->applytranspose = NULL;
1209:   pc->ops->setup          = PCSetUp_BJKOKKOS;
1210:   pc->ops->reset          = PCReset_BJKOKKOS;
1211:   pc->ops->destroy        = PCDestroy_BJKOKKOS;
1212:   pc->ops->setfromoptions = PCSetFromOptions_BJKOKKOS;
1213:   pc->ops->view           = PCView_BJKOKKOS;
1214:   pc->ops->postsolve      = PCPostSolve_BJKOKKOS;
1215:   pc->ops->presolve       = PCPreSolve_BJKOKKOS;

1217:   jac->rowOffsets   = NULL;
1218:   jac->colIndices   = NULL;
1219:   jac->batch_b      = NULL;
1220:   jac->batch_x      = NULL;
1221:   jac->batch_values = NULL;

1223:   PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCBJKOKKOSGetKSP_C", PCBJKOKKOSGetKSP_BJKOKKOS));
1224:   PetscCall(PetscObjectComposeFunction((PetscObject)pc, "PCBJKOKKOSSetKSP_C", PCBJKOKKOSSetKSP_BJKOKKOS));
1225:   PetscFunctionReturn(PETSC_SUCCESS);
1226: }