xref: /petsc/src/ksp/pc/impls/bddc/bddcschurs.c (revision 9221af80bf5c05d1484c22c2c5741111019a0a00)
1 #include <../src/ksp/pc/impls/bddc/bddc.h>
2 #include <../src/ksp/pc/impls/bddc/bddcprivate.h>
3 
4 static PetscErrorCode PCBDDCAdjGetNextLayer_Private(PetscInt*,PetscInt,PetscBT,PetscInt*,PetscInt*,PetscInt*);
5 
6 #undef __FUNCT__
7 #define __FUNCT__ "PCBDDCSubSchursSetUpNew"
8 PetscErrorCode PCBDDCSubSchursSetUpNew(PCBDDCSubSchurs sub_schurs, PetscInt xadj[], PetscInt adjncy[], PetscInt nlayers)
9 {
10   Mat                    A_II,A_IB,A_BI,A_BB;
11   Mat                    AE_II,*AE_IE,*AE_EI,*AE_EE;
12   Mat                    global_schur_subsets,*submat_global_schur_subsets,work_mat;
13   ISLocalToGlobalMapping l2gmap_subsets;
14   IS                     is_I,*is_subset_B,temp_is;
15   PetscInt               *nnz,*all_local_idx_G,*all_local_idx_B,*all_local_idx_N,*all_permutation_G;
16   PetscInt               i,subset_size,max_subset_size;
17   PetscInt               local_size,global_size;
18   PetscBool              implicit_schurs;
19   PetscErrorCode         ierr;
20 
21   PetscFunctionBegin;
22   //ierr = PetscObjectTypeCompare((PetscObject)sub_schurs->S,MATSCHURCOMPLEMENT,&implicit_schurs);CHKERRQ(ierr);
23   implicit_schurs = PETSC_TRUE;
24   /* allocate space for schur complements */
25   ierr = PetscMalloc5(sub_schurs->n_subs,&sub_schurs->is_AEj_I,
26                       sub_schurs->n_subs,&sub_schurs->is_AEj_B,
27                       sub_schurs->n_subs,&sub_schurs->S_Ej,
28                       sub_schurs->n_subs,&sub_schurs->work1,
29                       sub_schurs->n_subs,&sub_schurs->work2);CHKERRQ(ierr);
30 
31   /* get Schur complement matrices */
32   if (implicit_schurs) {
33     ierr = MatSchurComplementGetSubMatrices(sub_schurs->S,&A_II,NULL,&A_IB,&A_BI,&A_BB);CHKERRQ(ierr);
34     ierr = PetscMalloc4(sub_schurs->n_subs,&is_subset_B,
35                         sub_schurs->n_subs,&AE_IE,
36                         sub_schurs->n_subs,&AE_EI,
37                         sub_schurs->n_subs,&AE_EE);CHKERRQ(ierr);
38   }
39 
40   /* determine interior problems */
41   if (nlayers >= 0 && xadj != NULL && adjncy != NULL) { /* Interior problems can be different from the original one */
42     PetscBT                touched;
43     const PetscInt*        idx_B;
44     PetscInt               n_I,n_B,n_local_dofs,n_prev_added,j,layer,*local_numbering;
45 
46     /* get sizes */
47     ierr = ISGetLocalSize(sub_schurs->is_I,&n_I);CHKERRQ(ierr);
48     ierr = ISGetLocalSize(sub_schurs->is_B,&n_B);CHKERRQ(ierr);
49 
50     ierr = PetscMalloc1(n_I+n_B,&local_numbering);CHKERRQ(ierr);
51     ierr = PetscBTCreate(n_I+n_B,&touched);CHKERRQ(ierr);
52     ierr = PetscBTMemzero(n_I+n_B,touched);CHKERRQ(ierr);
53 
54     /* all boundary dofs must be skipped when adding layers */
55     ierr = ISGetIndices(sub_schurs->is_B,&idx_B);CHKERRQ(ierr);
56     for (j=0;j<n_B;j++) {
57       ierr = PetscBTSet(touched,idx_B[j]);CHKERRQ(ierr);
58     }
59     ierr = PetscMemcpy(local_numbering,idx_B,n_B*sizeof(PetscInt));CHKERRQ(ierr);
60     ierr = ISRestoreIndices(sub_schurs->is_B,&idx_B);CHKERRQ(ierr);
61 
62     /* add prescribed number of layers of dofs */
63     n_local_dofs = n_B;
64     n_prev_added = n_B;
65     for (layer=0;layer<nlayers;layer++) {
66       PetscInt n_added;
67       if (n_local_dofs == n_I+n_B) break;
68       if (n_local_dofs > n_I+n_B) {
69         SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Error querying layer %d. Out of bound access (%d > %d)",layer,n_local_dofs,n_I+n_B);
70       }
71       ierr = PCBDDCAdjGetNextLayer_Private(local_numbering+n_local_dofs,n_prev_added,touched,xadj,adjncy,&n_added);CHKERRQ(ierr);
72       n_prev_added = n_added;
73       n_local_dofs += n_added;
74       if (!n_added) break;
75     }
76     ierr = PetscBTDestroy(&touched);CHKERRQ(ierr);
77 
78     /* IS for I dofs in original numbering */
79     ierr = ISCreateGeneral(PetscObjectComm((PetscObject)sub_schurs->is_I),n_local_dofs-n_B,local_numbering+n_B,PETSC_COPY_VALUES,&sub_schurs->is_AEj_I[0]);CHKERRQ(ierr);
80     ierr = PetscFree(local_numbering);CHKERRQ(ierr);
81     ierr = ISSort(sub_schurs->is_AEj_I[0]);CHKERRQ(ierr);
82     /* IS for I dofs in boundary numbering */
83     if (implicit_schurs) {
84       ISLocalToGlobalMapping ItoNmap;
85       ierr = ISLocalToGlobalMappingCreateIS(sub_schurs->is_I,&ItoNmap);CHKERRQ(ierr);
86       ierr = ISGlobalToLocalMappingApplyIS(ItoNmap,IS_GTOLM_DROP,sub_schurs->is_AEj_I[0],&is_I);CHKERRQ(ierr);
87       ierr = ISLocalToGlobalMappingDestroy(&ItoNmap);CHKERRQ(ierr);
88 
89       /* II block */
90       ierr = MatGetSubMatrix(A_II,is_I,is_I,MAT_INITIAL_MATRIX,&AE_II);CHKERRQ(ierr);
91     }
92   } else {
93     PetscInt n_I;
94 
95     /* IS for I dofs in original numbering */
96     ierr = PetscObjectReference((PetscObject)sub_schurs->is_I);CHKERRQ(ierr);
97     sub_schurs->is_AEj_I[0] = sub_schurs->is_I;
98 
99     /* IS for I dofs in I numbering (strided 1) */
100     if (implicit_schurs) {
101       ierr = ISGetSize(sub_schurs->is_I,&n_I);CHKERRQ(ierr);
102       ierr = ISCreateStride(PetscObjectComm((PetscObject)sub_schurs->is_I),n_I,0,1,&is_I);CHKERRQ(ierr);
103 
104       /* II block is the same */
105       ierr = PetscObjectReference((PetscObject)A_II);CHKERRQ(ierr);
106       AE_II = A_II;
107     }
108   }
109 
110   /* TODO: just for compatibility with the previous version, needs to be fixed */
111   for (i=1;i<sub_schurs->n_subs;i++) {
112     ierr = PetscObjectReference((PetscObject)sub_schurs->is_AEj_I[0]);CHKERRQ(ierr);
113     sub_schurs->is_AEj_I[i] = sub_schurs->is_AEj_I[0];
114   }
115 
116   if (implicit_schurs) {
117     /* subsets in original and boundary numbering */
118     for (i=0;i<sub_schurs->n_subs;i++) {
119       ierr = ISDuplicate(sub_schurs->is_subs[i],&sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
120       ierr = ISSort(sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
121       ierr = ISGlobalToLocalMappingApplyIS(sub_schurs->BtoNmap,IS_GTOLM_DROP,sub_schurs->is_AEj_B[i],&is_subset_B[i]);CHKERRQ(ierr);
122     }
123 
124     /* EE block */
125     for (i=0;i<sub_schurs->n_subs;i++) {
126       ierr = MatGetSubMatrix(A_BB,is_subset_B[i],is_subset_B[i],MAT_INITIAL_MATRIX,&AE_EE[i]);CHKERRQ(ierr);
127     }
128     /* IE block */
129     for (i=0;i<sub_schurs->n_subs;i++) {
130       ierr = MatGetSubMatrix(A_IB,is_I,is_subset_B[i],MAT_INITIAL_MATRIX,&AE_IE[i]);CHKERRQ(ierr);
131     }
132     /* EI block */
133     for (i=0;i<sub_schurs->n_subs;i++) {
134       ierr = MatGetSubMatrix(A_BI,is_subset_B[i],is_I,MAT_INITIAL_MATRIX,&AE_EI[i]);CHKERRQ(ierr);
135     }
136 
137     /* setup Schur complements on subset */
138     for (i=0;i<sub_schurs->n_subs;i++) {
139       ierr = MatCreateSchurComplement(AE_II,AE_II,AE_IE[i],AE_EI[i],AE_EE[i],&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
140       if (AE_II == A_II) { /* we can reuse the same ksp */
141         KSP ksp;
142         ierr = MatSchurComplementGetKSP(sub_schurs->S,&ksp);CHKERRQ(ierr);
143         ierr = MatSchurComplementSetKSP(sub_schurs->S_Ej[i],ksp);CHKERRQ(ierr);
144       } else { /* build new ksp object which inherits ksp and pc types from the original one */
145         KSP      origksp,schurksp;
146         PC       origpc,schurpc;
147         KSPType  ksp_type;
148         PCType   pc_type;
149         PetscInt n_internal;
150 
151         ierr = MatSchurComplementGetKSP(sub_schurs->S,&origksp);CHKERRQ(ierr);
152         ierr = MatSchurComplementGetKSP(sub_schurs->S_Ej[i],&schurksp);CHKERRQ(ierr);
153         ierr = KSPGetType(origksp,&ksp_type);CHKERRQ(ierr);
154         ierr = KSPSetType(schurksp,ksp_type);CHKERRQ(ierr);
155         ierr = KSPGetPC(schurksp,&schurpc);CHKERRQ(ierr);
156         ierr = KSPGetPC(origksp,&origpc);CHKERRQ(ierr);
157         ierr = PCGetType(origpc,&pc_type);CHKERRQ(ierr);
158         ierr = PCSetType(schurpc,pc_type);CHKERRQ(ierr);
159         ierr = ISGetSize(is_I,&n_internal);CHKERRQ(ierr);
160         if (n_internal) { /* UMFPACK gives error with 0 sized problems */
161           MatSolverPackage solver=NULL;
162           ierr = PCFactorGetMatSolverPackage(origpc,(const MatSolverPackage*)&solver);CHKERRQ(ierr);
163           if (solver) {
164             ierr = PCFactorSetMatSolverPackage(schurpc,solver);CHKERRQ(ierr);
165           }
166         }
167         ierr = KSPSetUp(schurksp);CHKERRQ(ierr);
168       }
169     }
170     /* free */
171     ierr = ISDestroy(&is_I);CHKERRQ(ierr);
172     ierr = MatDestroy(&AE_II);CHKERRQ(ierr);
173     for (i=0;i<sub_schurs->n_subs;i++) {
174       ierr = MatDestroy(&AE_EE[i]);CHKERRQ(ierr);
175       ierr = MatDestroy(&AE_IE[i]);CHKERRQ(ierr);
176       ierr = MatDestroy(&AE_EI[i]);CHKERRQ(ierr);
177       ierr = ISDestroy(&is_subset_B[i]);CHKERRQ(ierr);
178     }
179     ierr = PetscFree4(is_subset_B,AE_IE,AE_EI,AE_EE);CHKERRQ(ierr);
180   }
181 
182   /* TODO: just for compatibility with the previous version, needs to be fixed */
183   for (i=0;i<sub_schurs->n_subs_par;i++) {
184     PetscInt j = sub_schurs->index_parallel[i];
185     ierr = MatCreateVecs(sub_schurs->S_Ej[j],&sub_schurs->work1[j],&sub_schurs->work2[j]);CHKERRQ(ierr);
186   }
187   for (i=0;i<sub_schurs->n_subs_seq;i++) {
188      sub_schurs->work1[sub_schurs->index_sequential[i]] = 0;
189      sub_schurs->work2[sub_schurs->index_sequential[i]] = 0;
190   }
191 
192   if (!sub_schurs->n_subs_seq_g) {
193     sub_schurs->S_Ej_all = 0;
194     sub_schurs->sum_S_Ej_all = 0;
195     sub_schurs->is_Ej_all = 0;
196     PetscFunctionReturn(0);
197   }
198 
199   /* Get info on subset sizes and sum of all subsets sizes */
200   max_subset_size = 0;
201   local_size = 0;
202   for (i=0;i<sub_schurs->n_subs_seq;i++) {
203     PetscInt j = sub_schurs->index_sequential[i];
204     ierr = ISGetLocalSize(sub_schurs->is_AEj_B[j],&subset_size);CHKERRQ(ierr);
205     max_subset_size = PetscMax(subset_size,max_subset_size);
206     local_size += subset_size;
207   }
208 
209   /* Work arrays for local indices */
210   ierr = PetscMalloc1(local_size,&all_local_idx_B);CHKERRQ(ierr);
211   ierr = PetscMalloc1(local_size,&all_local_idx_N);CHKERRQ(ierr);
212   ierr = PetscMalloc1(local_size,&nnz);CHKERRQ(ierr);
213 
214   /* Get local indices in local whole numbering and local boundary numbering */
215   local_size = 0;
216   for (i=0;i<sub_schurs->n_subs_seq;i++) {
217     PetscInt j;
218     const    PetscInt *idxs;
219 
220     PetscInt local_problem_index = sub_schurs->index_sequential[i];
221     ierr = ISGetLocalSize(sub_schurs->is_AEj_B[local_problem_index],&subset_size);CHKERRQ(ierr);
222     ierr = ISGetIndices(sub_schurs->is_AEj_B[local_problem_index],&idxs);CHKERRQ(ierr);
223     /* subset indices in local numbering */
224     ierr = PetscMemcpy(all_local_idx_N+local_size,idxs,subset_size*sizeof(PetscInt));CHKERRQ(ierr);
225     ierr = ISRestoreIndices(sub_schurs->is_AEj_B[local_problem_index],&idxs);CHKERRQ(ierr);
226     for (j=0;j<subset_size;j++) nnz[local_size+j] = subset_size;
227     local_size += subset_size;
228   }
229 
230   /* subset indices in local boundary numbering */
231   ierr = ISGlobalToLocalMappingApply(sub_schurs->BtoNmap,IS_GTOLM_DROP,local_size,all_local_idx_N,&subset_size,all_local_idx_B);CHKERRQ(ierr);
232   if (subset_size != local_size) {
233     SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Error in sub_schurs serial (BtoNmap)! %d != %d\n",subset_size,local_size);
234   }
235   ierr = ISCreateGeneral(PETSC_COMM_SELF,local_size,all_local_idx_B,PETSC_OWN_POINTER,&sub_schurs->is_Ej_all);CHKERRQ(ierr);
236 
237   /* Number dofs on all subsets (parallel) and sort numbering */
238   ierr = PCBDDCSubsetNumbering(PetscObjectComm((PetscObject)sub_schurs->l2gmap),sub_schurs->l2gmap,local_size,all_local_idx_N,PETSC_NULL,&global_size,&all_local_idx_G);CHKERRQ(ierr);
239   ierr = PetscMalloc1(local_size,&all_permutation_G);CHKERRQ(ierr);
240   for (i=0;i<local_size;i++) {
241     all_permutation_G[i]=i;
242   }
243   ierr = PetscSortIntWithPermutation(local_size,all_local_idx_G,all_permutation_G);CHKERRQ(ierr);
244 
245   /* Local matrix of all local Schur on subsets */
246   ierr = MatCreate(PETSC_COMM_SELF,&sub_schurs->S_Ej_all);CHKERRQ(ierr);
247   ierr = MatSetSizes(sub_schurs->S_Ej_all,PETSC_DECIDE,PETSC_DECIDE,local_size,local_size);CHKERRQ(ierr);
248   ierr = MatSetType(sub_schurs->S_Ej_all,MATAIJ);CHKERRQ(ierr);
249   ierr = MatSeqAIJSetPreallocation(sub_schurs->S_Ej_all,0,nnz);CHKERRQ(ierr);
250   ierr = PetscFree(nnz);CHKERRQ(ierr);
251 
252   if (implicit_schurs) {
253     PetscScalar *fill_vals;
254     PetscInt    *dummy_idx;
255 
256     ierr = MatSetOption(sub_schurs->S_Ej_all,MAT_ROW_ORIENTED,PETSC_FALSE);CHKERRQ(ierr);
257 
258     /* Work arrays */
259     ierr = PetscMalloc2(max_subset_size,&dummy_idx,max_subset_size*max_subset_size,&fill_vals);CHKERRQ(ierr);
260 
261     /* Loop on local problems to compute Schur complements explicitly (TODO; optimize)*/
262     local_size = 0;
263     for (i=0;i<sub_schurs->n_subs_seq;i++) {
264       Vec work1,work2;
265       PetscInt j,local_problem_index = sub_schurs->index_sequential[i];
266 
267       ierr = MatCreateVecs(sub_schurs->S_Ej[local_problem_index],&work1,&work2);CHKERRQ(ierr);
268       ierr = ISGetLocalSize(sub_schurs->is_AEj_B[local_problem_index],&subset_size);CHKERRQ(ierr);
269       /* local Schur */
270       for (j=0;j<subset_size;j++) {
271         ierr = VecSet(work1,0.0);CHKERRQ(ierr);
272         ierr = VecSetValue(work1,j,1.0,INSERT_VALUES);CHKERRQ(ierr);
273         ierr = VecPlaceArray(work2,&fill_vals[j*subset_size]);CHKERRQ(ierr);
274         ierr = MatMult(sub_schurs->S_Ej[local_problem_index],work1,work2);CHKERRQ(ierr);
275         ierr = VecResetArray(work2);CHKERRQ(ierr);
276       }
277       for (j=0;j<subset_size;j++) {
278         dummy_idx[j]=local_size+j;
279       }
280       ierr = MatSetValues(sub_schurs->S_Ej_all,subset_size,dummy_idx,subset_size,dummy_idx,fill_vals,INSERT_VALUES);CHKERRQ(ierr);
281       local_size += subset_size;
282       ierr = VecDestroy(&work1);CHKERRQ(ierr);
283       ierr = VecDestroy(&work2);CHKERRQ(ierr);
284     }
285     ierr = PetscFree2(dummy_idx,fill_vals);CHKERRQ(ierr);
286   }
287   ierr = MatAssemblyBegin(sub_schurs->S_Ej_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
288   ierr = MatAssemblyEnd(sub_schurs->S_Ej_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
289 
290   /* Global matrix of all assembled Schur on subsets */
291   ierr = ISLocalToGlobalMappingCreate(PetscObjectComm((PetscObject)sub_schurs->l2gmap),1,local_size,all_local_idx_G,PETSC_COPY_VALUES,&l2gmap_subsets);CHKERRQ(ierr);
292   ierr = MatCreateIS(PetscObjectComm((PetscObject)sub_schurs->l2gmap),1,PETSC_DECIDE,PETSC_DECIDE,global_size,global_size,l2gmap_subsets,&work_mat);CHKERRQ(ierr);
293   ierr = ISLocalToGlobalMappingDestroy(&l2gmap_subsets);CHKERRQ(ierr);
294   ierr = MatISSetLocalMat(work_mat,sub_schurs->S_Ej_all);CHKERRQ(ierr);
295   ierr = MatISGetMPIXAIJ(work_mat,MAT_INITIAL_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
296   ierr = MatDestroy(&work_mat);CHKERRQ(ierr);
297 
298   /* Get local part of (\sum_j S_Ej) */
299   for (i=0;i<local_size;i++) {
300     all_local_idx_N[i] = all_local_idx_G[all_permutation_G[i]];
301   }
302   ierr = ISCreateGeneral(PetscObjectComm((PetscObject)sub_schurs->l2gmap),local_size,all_local_idx_N,PETSC_OWN_POINTER,&temp_is);CHKERRQ(ierr);
303   ierr = MatGetSubMatrices(global_schur_subsets,1,&temp_is,&temp_is,MAT_INITIAL_MATRIX,&submat_global_schur_subsets);CHKERRQ(ierr);
304   ierr = MatDestroy(&global_schur_subsets);CHKERRQ(ierr);
305   ierr = ISDestroy(&temp_is);CHKERRQ(ierr);
306   for (i=0;i<local_size;i++) {
307     all_local_idx_G[all_permutation_G[i]] = i;
308   }
309   ierr = ISCreateGeneral(PETSC_COMM_SELF,local_size,all_local_idx_G,PETSC_OWN_POINTER,&temp_is);CHKERRQ(ierr);
310   ierr = ISSetPermutation(temp_is);CHKERRQ(ierr);
311   ierr = MatPermute(submat_global_schur_subsets[0],temp_is,temp_is,&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
312   ierr = MatDestroyMatrices(1,&submat_global_schur_subsets);CHKERRQ(ierr);
313   ierr = ISDestroy(&temp_is);CHKERRQ(ierr);
314   ierr = PetscFree(all_permutation_G);CHKERRQ(ierr);
315   PetscFunctionReturn(0);
316 }
317 
318 #undef __FUNCT__
319 #define __FUNCT__ "PCBDDCSubSchursInit"
320 PetscErrorCode PCBDDCSubSchursInit(PCBDDCSubSchurs sub_schurs, Mat A, Mat S, IS is_I, IS is_B, PCBDDCGraph graph, ISLocalToGlobalMapping BtoNmap, PetscInt seqthreshold)
321 {
322   IS                  *faces,*edges,*all_cc;
323   PetscInt            *index_sequential,*index_parallel;
324   PetscInt            *auxlocal_sequential,*auxlocal_parallel;
325   PetscInt            *auxglobal_sequential,*auxglobal_parallel;
326   PetscInt            *auxmapping;//,*idxs;
327   PetscInt            i,max_subset_size;
328   PetscInt            n_sequential_problems,n_local_sequential_problems,n_parallel_problems,n_local_parallel_problems;
329   PetscInt            n_faces,n_edges,n_all_cc;
330   PetscBool           is_sorted;
331   PetscErrorCode  ierr;
332 
333   PetscFunctionBegin;
334   ierr = ISSorted(is_I,&is_sorted);CHKERRQ(ierr);
335   if (!is_sorted) {
336     SETERRQ(PetscObjectComm((PetscObject)is_I),PETSC_ERR_PLIB,"IS for I dofs should be shorted");
337   }
338   ierr = ISSorted(is_B,&is_sorted);CHKERRQ(ierr);
339   if (!is_sorted) {
340     SETERRQ(PetscObjectComm((PetscObject)is_B),PETSC_ERR_PLIB,"IS for B dofs should be shorted");
341   }
342 
343   /* reset any previous data */
344   ierr = PCBDDCSubSchursReset(sub_schurs);CHKERRQ(ierr);
345 
346   /* get index sets for faces and edges */
347   ierr = PCBDDCGraphGetCandidatesIS(graph,&n_faces,&faces,&n_edges,&edges,NULL);CHKERRQ(ierr);
348   n_all_cc = n_faces+n_edges;
349   ierr = PetscMalloc1(n_all_cc,&all_cc);CHKERRQ(ierr);
350   for (i=0;i<n_faces;i++) {
351     all_cc[i] = faces[i];
352   }
353   for (i=0;i<n_edges;i++) {
354     all_cc[n_faces+i] = edges[i];
355   }
356   ierr = PetscFree(faces);CHKERRQ(ierr);
357   ierr = PetscFree(edges);CHKERRQ(ierr);
358 
359   /* map interface's subsets */
360   max_subset_size = 0;
361   for (i=0;i<n_all_cc;i++) {
362     PetscInt subset_size;
363     ierr = ISGetLocalSize(all_cc[i],&subset_size);CHKERRQ(ierr);
364     max_subset_size = PetscMax(max_subset_size,subset_size);
365   }
366   ierr = PetscMalloc1(max_subset_size,&auxmapping);CHKERRQ(ierr);
367   ierr = PetscMalloc2(graph->ncc,&auxlocal_sequential,
368                       graph->ncc,&auxlocal_parallel);CHKERRQ(ierr);
369   ierr = PetscMalloc2(graph->ncc,&index_sequential,
370                       graph->ncc,&index_parallel);CHKERRQ(ierr);
371 
372   /* if threshold is negative, uses all sequential problems */
373   if (seqthreshold < 0) seqthreshold = max_subset_size;
374 
375   /* determine which problem has to be solved in parallel or sequentially */
376   n_local_sequential_problems = 0;
377   n_local_parallel_problems = 0;
378   for (i=0;i<n_all_cc;i++) {
379     PetscInt       subset_size,j,min_loc = 0;
380     const PetscInt *idxs;
381 
382     ierr = ISGetLocalSize(all_cc[i],&subset_size);CHKERRQ(ierr);
383     ierr = ISGetIndices(all_cc[i],&idxs);CHKERRQ(ierr);
384     ierr = ISLocalToGlobalMappingApply(graph->l2gmap,subset_size,idxs,auxmapping);CHKERRQ(ierr);
385     for (j=1;j<subset_size;j++) {
386       if (auxmapping[j]<auxmapping[min_loc]) {
387         min_loc = j;
388       }
389     }
390     if (subset_size > seqthreshold) {
391       index_parallel[n_local_parallel_problems] = i;
392       auxlocal_parallel[n_local_parallel_problems] = idxs[min_loc];
393       n_local_parallel_problems++;
394     } else {
395       index_sequential[n_local_sequential_problems] = i;
396       auxlocal_sequential[n_local_sequential_problems] = idxs[min_loc];
397       n_local_sequential_problems++;
398     }
399     ierr = ISRestoreIndices(all_cc[i],&idxs);CHKERRQ(ierr);
400   }
401 
402   /* Number parallel problems */
403   auxglobal_parallel = 0;
404   ierr = PCBDDCSubsetNumbering(PetscObjectComm((PetscObject)graph->l2gmap),graph->l2gmap,n_local_parallel_problems,auxlocal_parallel,PETSC_NULL,&n_parallel_problems,&auxglobal_parallel);CHKERRQ(ierr);
405 
406   /* Number sequential problems */
407   auxglobal_sequential = 0;
408   ierr = PCBDDCSubsetNumbering(PetscObjectComm((PetscObject)graph->l2gmap),graph->l2gmap,n_local_sequential_problems,auxlocal_sequential,PETSC_NULL,&n_sequential_problems,&auxglobal_sequential);CHKERRQ(ierr);
409 
410   /* update info in sub_schurs */
411   if (A) {
412     ierr = PetscObjectReference((PetscObject)A);CHKERRQ(ierr);
413     sub_schurs->A = A;
414   }
415   ierr = PetscObjectReference((PetscObject)S);CHKERRQ(ierr);
416   sub_schurs->S = S;
417   ierr = PetscObjectReference((PetscObject)is_I);CHKERRQ(ierr);
418   sub_schurs->is_I = is_I;
419   ierr = PetscObjectReference((PetscObject)is_B);CHKERRQ(ierr);
420   sub_schurs->is_B = is_B;
421   ierr = PetscObjectReference((PetscObject)graph->l2gmap);CHKERRQ(ierr);
422   sub_schurs->l2gmap = graph->l2gmap;
423   ierr = PetscObjectReference((PetscObject)BtoNmap);CHKERRQ(ierr);
424   sub_schurs->BtoNmap = BtoNmap;
425   sub_schurs->n_subs_seq = n_local_sequential_problems;
426   sub_schurs->n_subs_par = n_local_parallel_problems;
427   sub_schurs->n_subs_seq_g = n_sequential_problems;
428   sub_schurs->n_subs_par_g = n_parallel_problems;
429   sub_schurs->n_subs = sub_schurs->n_subs_seq + sub_schurs->n_subs_par;
430   sub_schurs->is_subs = all_cc;
431   sub_schurs->index_sequential = index_sequential;
432   sub_schurs->index_parallel = index_parallel;
433   sub_schurs->auxglobal_sequential = auxglobal_sequential;
434   sub_schurs->auxglobal_parallel = auxglobal_parallel;
435 
436   /* free workspace */
437   ierr = PetscFree(auxmapping);CHKERRQ(ierr);
438   ierr = PetscFree2(auxlocal_sequential,auxlocal_parallel);CHKERRQ(ierr);
439 
440   PetscFunctionReturn(0);
441 }
442 
443 #undef __FUNCT__
444 #define __FUNCT__ "PCBDDCSubSchursCreate"
445 PetscErrorCode PCBDDCSubSchursCreate(PCBDDCSubSchurs *sub_schurs)
446 {
447   PCBDDCSubSchurs schurs_ctx;
448   PetscErrorCode  ierr;
449 
450   PetscFunctionBegin;
451   ierr = PetscNew(&schurs_ctx);CHKERRQ(ierr);
452   schurs_ctx->n_subs = 0;
453   *sub_schurs = schurs_ctx;
454   PetscFunctionReturn(0);
455 }
456 
457 #undef __FUNCT__
458 #define __FUNCT__ "PCBDDCSubSchursDestroy"
459 PetscErrorCode PCBDDCSubSchursDestroy(PCBDDCSubSchurs *sub_schurs)
460 {
461   PetscErrorCode ierr;
462 
463   PetscFunctionBegin;
464   ierr = PCBDDCSubSchursReset(*sub_schurs);CHKERRQ(ierr);
465   ierr = PetscFree(*sub_schurs);CHKERRQ(ierr);
466   PetscFunctionReturn(0);
467 }
468 
469 #undef __FUNCT__
470 #define __FUNCT__ "PCBDDCSubSchursReset"
471 PetscErrorCode PCBDDCSubSchursReset(PCBDDCSubSchurs sub_schurs)
472 {
473   PetscInt       i;
474   PetscErrorCode ierr;
475 
476   PetscFunctionBegin;
477   ierr = MatDestroy(&sub_schurs->A);CHKERRQ(ierr);
478   ierr = MatDestroy(&sub_schurs->S);CHKERRQ(ierr);
479   ierr = ISDestroy(&sub_schurs->is_I);CHKERRQ(ierr);
480   ierr = ISDestroy(&sub_schurs->is_B);CHKERRQ(ierr);
481   ierr = ISLocalToGlobalMappingDestroy(&sub_schurs->l2gmap);CHKERRQ(ierr);
482   ierr = ISLocalToGlobalMappingDestroy(&sub_schurs->BtoNmap);CHKERRQ(ierr);
483   ierr = MatDestroy(&sub_schurs->S_Ej_all);CHKERRQ(ierr);
484   ierr = MatDestroy(&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
485   ierr = ISDestroy(&sub_schurs->is_Ej_all);CHKERRQ(ierr);
486   for (i=0;i<sub_schurs->n_subs;i++) {
487     ierr = ISDestroy(&sub_schurs->is_subs[i]);CHKERRQ(ierr);
488     ierr = ISDestroy(&sub_schurs->is_AEj_I[i]);CHKERRQ(ierr);
489     ierr = ISDestroy(&sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
490     ierr = MatDestroy(&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
491     ierr = VecDestroy(&sub_schurs->work1[i]);CHKERRQ(ierr);
492     ierr = VecDestroy(&sub_schurs->work2[i]);CHKERRQ(ierr);
493   }
494   if (sub_schurs->n_subs) {
495     ierr = PetscFree(sub_schurs->is_subs);CHKERRQ(ierr);
496     ierr = PetscFree5(sub_schurs->is_AEj_I,sub_schurs->is_AEj_B,sub_schurs->S_Ej,sub_schurs->work1,sub_schurs->work2);CHKERRQ(ierr);
497     ierr = PetscFree2(sub_schurs->index_sequential,sub_schurs->index_parallel);CHKERRQ(ierr);
498     ierr = PetscFree(sub_schurs->auxglobal_sequential);CHKERRQ(ierr);
499     ierr = PetscFree(sub_schurs->auxglobal_parallel);CHKERRQ(ierr);
500   }
501   sub_schurs->n_subs = 0;
502   PetscFunctionReturn(0);
503 }
504 
505 #undef __FUNCT__
506 #define __FUNCT__ "PCBDDCAdjGetNextLayer_Private"
507 PETSC_STATIC_INLINE PetscErrorCode PCBDDCAdjGetNextLayer_Private(PetscInt* queue_tip,PetscInt n_prev,PetscBT touched,PetscInt* xadj,PetscInt* adjncy,PetscInt* n_added)
508 {
509   PetscInt       i,j,n;
510   PetscErrorCode ierr;
511 
512   PetscFunctionBegin;
513   n = 0;
514   for (i=-n_prev;i<0;i++) {
515     PetscInt start_dof = queue_tip[i];
516     for (j=xadj[start_dof];j<xadj[start_dof+1];j++) {
517       PetscInt dof = adjncy[j];
518       if (!PetscBTLookup(touched,dof)) {
519         ierr = PetscBTSet(touched,dof);CHKERRQ(ierr);
520         queue_tip[n] = dof;
521         n++;
522       }
523     }
524   }
525   *n_added = n;
526   PetscFunctionReturn(0);
527 }
528 
529 #undef __FUNCT__
530 #define __FUNCT__ "PCBDDCSubSchursSetUp"
531 PetscErrorCode PCBDDCSubSchursSetUp(PCBDDCSubSchurs sub_schurs, Mat S, IS is_A_I, IS is_A_B, PetscInt ncc, IS is_cc[], PetscInt xadj[], PetscInt adjncy[], PetscInt nlayers)
532 {
533   Mat                    A_II,A_IB,A_BI,A_BB;
534   Mat                    AE_II,*AE_IE,*AE_EI,*AE_EE;
535   IS                     is_I,*is_subset_B;
536   ISLocalToGlobalMapping BtoNmap;
537   PetscInt               i;
538   PetscBool              is_sorted;
539   PetscErrorCode         ierr;
540 
541   PetscFunctionBegin;
542   ierr = ISSorted(is_A_I,&is_sorted);CHKERRQ(ierr);
543   if (!is_sorted) {
544     SETERRQ(PetscObjectComm((PetscObject)is_A_I),PETSC_ERR_PLIB,"IS for I dofs should be shorted");
545   }
546   ierr = ISSorted(is_A_B,&is_sorted);CHKERRQ(ierr);
547   if (!is_sorted) {
548     SETERRQ(PetscObjectComm((PetscObject)is_A_B),PETSC_ERR_PLIB,"IS for B dofs should be shorted");
549   }
550 
551   /* get Schur complement matrices */
552   ierr = MatSchurComplementGetSubMatrices(S,&A_II,NULL,&A_IB,&A_BI,&A_BB);CHKERRQ(ierr);
553 
554   /* allocate space for schur complements */
555   ierr = PetscMalloc5(sub_schurs->n_subs,&sub_schurs->is_AEj_I,
556                       sub_schurs->n_subs,&sub_schurs->is_AEj_B,
557                       sub_schurs->n_subs,&sub_schurs->S_Ej,
558                       sub_schurs->n_subs,&sub_schurs->work1,
559                       sub_schurs->n_subs,&sub_schurs->work2);CHKERRQ(ierr);
560   ierr = PetscMalloc4(ncc,&is_subset_B,ncc,&AE_IE,ncc,&AE_EI,ncc,&AE_EE);CHKERRQ(ierr);
561   sub_schurs->n_subs = ncc;
562 
563   /* maps */
564   if (sub_schurs->n_subs && nlayers >= 0 && xadj != NULL && adjncy != NULL) { /* Interior problems can be different from the original one */
565     ISLocalToGlobalMapping ItoNmap;
566     PetscBT                touched;
567     const PetscInt*        idx_B;
568     PetscInt               n_I,n_B,n_local_dofs,n_prev_added,j,layer,*local_numbering;
569 
570     /* get sizes */
571     ierr = ISGetLocalSize(is_A_I,&n_I);CHKERRQ(ierr);
572     ierr = ISGetLocalSize(is_A_B,&n_B);CHKERRQ(ierr);
573 
574     ierr = ISLocalToGlobalMappingCreateIS(is_A_I,&ItoNmap);CHKERRQ(ierr);
575     ierr = PetscMalloc1(n_I+n_B,&local_numbering);CHKERRQ(ierr);
576     ierr = PetscBTCreate(n_I+n_B,&touched);CHKERRQ(ierr);
577     ierr = PetscBTMemzero(n_I+n_B,touched);CHKERRQ(ierr);
578 
579     /* all boundary dofs must be skipped when adding layers */
580     ierr = ISGetIndices(is_A_B,&idx_B);CHKERRQ(ierr);
581     for (j=0;j<n_B;j++) {
582       ierr = PetscBTSet(touched,idx_B[j]);CHKERRQ(ierr);
583     }
584     ierr = PetscMemcpy(local_numbering,idx_B,n_B*sizeof(PetscInt));CHKERRQ(ierr);
585     ierr = ISRestoreIndices(is_A_B,&idx_B);CHKERRQ(ierr);
586 
587     /* add next layers of dofs */
588     n_local_dofs = n_B;
589     n_prev_added = n_B;
590     for (layer=0;layer<nlayers;layer++) {
591       PetscInt n_added;
592       if (n_local_dofs == n_I+n_B) break;
593       if (n_local_dofs > n_I+n_B) {
594         SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Error querying layer %d. Out of bound access (%d > %d)",layer,n_local_dofs,n_I+n_B);
595       }
596       ierr = PCBDDCAdjGetNextLayer_Private(local_numbering+n_local_dofs,n_prev_added,touched,xadj,adjncy,&n_added);CHKERRQ(ierr);
597       n_prev_added = n_added;
598       n_local_dofs += n_added;
599       if (!n_added) break;
600     }
601     ierr = PetscBTDestroy(&touched);CHKERRQ(ierr);
602 
603     /* IS for I dofs in original numbering and in I numbering */
604     ierr = ISCreateGeneral(PetscObjectComm((PetscObject)ItoNmap),n_local_dofs-n_B,local_numbering+n_B,PETSC_COPY_VALUES,&sub_schurs->is_AEj_I[0]);CHKERRQ(ierr);
605     ierr = PetscFree(local_numbering);CHKERRQ(ierr);
606     ierr = ISSort(sub_schurs->is_AEj_I[0]);CHKERRQ(ierr);
607     ierr = ISGlobalToLocalMappingApplyIS(ItoNmap,IS_GTOLM_DROP,sub_schurs->is_AEj_I[0],&is_I);CHKERRQ(ierr);
608     ierr = ISLocalToGlobalMappingDestroy(&ItoNmap);CHKERRQ(ierr);
609 
610     /* II block */
611     ierr = MatGetSubMatrix(A_II,is_I,is_I,MAT_INITIAL_MATRIX,&AE_II);CHKERRQ(ierr);
612   } else {
613     PetscInt n_I;
614 
615     /* IS for I dofs in original numbering */
616     ierr = PetscObjectReference((PetscObject)is_A_I);CHKERRQ(ierr);
617     sub_schurs->is_AEj_I[0] = is_A_I;
618 
619     /* IS for I dofs in I numbering (strided 1) */
620     ierr = ISGetSize(is_A_I,&n_I);CHKERRQ(ierr);
621     ierr = ISCreateStride(PetscObjectComm((PetscObject)is_A_I),n_I,0,1,&is_I);CHKERRQ(ierr);
622 
623     /* II block is the same */
624     ierr = PetscObjectReference((PetscObject)A_II);CHKERRQ(ierr);
625     AE_II = A_II;
626   }
627 
628   /* TODO: just for compatibility with the previous version, needs to be fixed */
629   for (i=1;i<sub_schurs->n_subs;i++) {
630     ierr = PetscObjectReference((PetscObject)sub_schurs->is_AEj_I[0]);CHKERRQ(ierr);
631     sub_schurs->is_AEj_I[i] = sub_schurs->is_AEj_I[0];
632   }
633 
634   /* subsets in original and boundary numbering */
635   ierr = ISLocalToGlobalMappingCreateIS(is_A_B,&BtoNmap);CHKERRQ(ierr);
636   for (i=0;i<sub_schurs->n_subs;i++) {
637     ierr = ISDuplicate(is_cc[i],&sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
638     ierr = ISSort(sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
639     ierr = ISGlobalToLocalMappingApplyIS(BtoNmap,IS_GTOLM_DROP,sub_schurs->is_AEj_B[i],&is_subset_B[i]);CHKERRQ(ierr);
640   }
641   ierr = ISLocalToGlobalMappingDestroy(&BtoNmap);CHKERRQ(ierr);
642 
643   /* EE block */
644   for (i=0;i<sub_schurs->n_subs;i++) {
645     ierr = MatGetSubMatrix(A_BB,is_subset_B[i],is_subset_B[i],MAT_INITIAL_MATRIX,&AE_EE[i]);CHKERRQ(ierr);
646   }
647   /* IE block */
648   for (i=0;i<sub_schurs->n_subs;i++) {
649     ierr = MatGetSubMatrix(A_IB,is_I,is_subset_B[i],MAT_INITIAL_MATRIX,&AE_IE[i]);CHKERRQ(ierr);
650   }
651   /* EI block */
652   for (i=0;i<sub_schurs->n_subs;i++) {
653     ierr = MatGetSubMatrix(A_BI,is_subset_B[i],is_I,MAT_INITIAL_MATRIX,&AE_EI[i]);CHKERRQ(ierr);
654   }
655 
656   /* setup Schur complements on subset */
657   for (i=0;i<sub_schurs->n_subs;i++) {
658     ierr = MatCreateSchurComplement(AE_II,AE_II,AE_IE[i],AE_EI[i],AE_EE[i],&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
659     ierr = MatCreateVecs(sub_schurs->S_Ej[i],&sub_schurs->work1[i],&sub_schurs->work2[i]);CHKERRQ(ierr);
660     if (AE_II == A_II) { /* we can reuse the same ksp */
661       KSP ksp;
662       ierr = MatSchurComplementGetKSP(S,&ksp);CHKERRQ(ierr);
663       ierr = MatSchurComplementSetKSP(sub_schurs->S_Ej[i],ksp);CHKERRQ(ierr);
664     } else { /* build new ksp object which inherits ksp and pc types from the original one */
665       KSP      origksp,schurksp;
666       PC       origpc,schurpc;
667       KSPType  ksp_type;
668       PCType   pc_type;
669       PetscInt n_internal;
670 
671       ierr = MatSchurComplementGetKSP(S,&origksp);CHKERRQ(ierr);
672       ierr = MatSchurComplementGetKSP(sub_schurs->S_Ej[i],&schurksp);CHKERRQ(ierr);
673       ierr = KSPGetType(origksp,&ksp_type);CHKERRQ(ierr);
674       ierr = KSPSetType(schurksp,ksp_type);CHKERRQ(ierr);
675       ierr = KSPGetPC(schurksp,&schurpc);CHKERRQ(ierr);
676       ierr = KSPGetPC(origksp,&origpc);CHKERRQ(ierr);
677       ierr = PCGetType(origpc,&pc_type);CHKERRQ(ierr);
678       ierr = PCSetType(schurpc,pc_type);CHKERRQ(ierr);
679       ierr = ISGetSize(is_I,&n_internal);CHKERRQ(ierr);
680       if (n_internal) { /* UMFPACK gives error with 0 sized problems */
681         MatSolverPackage solver=NULL;
682         ierr = PCFactorGetMatSolverPackage(origpc,(const MatSolverPackage*)&solver);CHKERRQ(ierr);
683         if (solver) {
684           ierr = PCFactorSetMatSolverPackage(schurpc,solver);CHKERRQ(ierr);
685         }
686       }
687       ierr = KSPSetUp(schurksp);CHKERRQ(ierr);
688     }
689   }
690   /* free */
691   ierr = ISDestroy(&is_I);CHKERRQ(ierr);
692   ierr = MatDestroy(&AE_II);CHKERRQ(ierr);
693   for (i=0;i<sub_schurs->n_subs;i++) {
694     ierr = MatDestroy(&AE_EE[i]);CHKERRQ(ierr);
695     ierr = MatDestroy(&AE_IE[i]);CHKERRQ(ierr);
696     ierr = MatDestroy(&AE_EI[i]);CHKERRQ(ierr);
697     ierr = ISDestroy(&is_subset_B[i]);CHKERRQ(ierr);
698   }
699   ierr = PetscFree4(is_subset_B,AE_IE,AE_EI,AE_EE);CHKERRQ(ierr);
700   PetscFunctionReturn(0);
701 }
702