xref: /petsc/src/ksp/pc/impls/bddc/bddcschurs.c (revision 5db18549ef4e876dcd315358182a0a733898e86f)
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 #if 0
183 ?????
184   if (!sub_schurs->n_subs_seq_g) {
185     PetscFunctionReturn(0);
186   }
187 ?????
188 #endif
189 
190 
191   /* Get info on subset sizes and sum of all subsets sizes */
192   max_subset_size = 0;
193   local_size = 0;
194   for (i=0;i<sub_schurs->n_subs_seq;i++) {
195     PetscInt j = sub_schurs->index_sequential[i];
196     ierr = ISGetLocalSize(sub_schurs->is_AEj_B[j],&subset_size);CHKERRQ(ierr);
197     max_subset_size = PetscMax(subset_size,max_subset_size);
198     local_size += subset_size;
199   }
200 
201   /* Work arrays for local indices */
202   ierr = PetscMalloc1(local_size,&all_local_idx_B);CHKERRQ(ierr);
203   ierr = PetscMalloc1(local_size,&all_local_idx_N);CHKERRQ(ierr);
204   ierr = PetscMalloc1(local_size,&nnz);CHKERRQ(ierr);
205 
206   /* Get local indices in local whole numbering and local boundary numbering */
207   local_size = 0;
208   for (i=0;i<sub_schurs->n_subs_seq;i++) {
209     PetscInt j;
210     const    PetscInt *idxs;
211 
212     PetscInt local_problem_index = sub_schurs->index_sequential[i];
213     ierr = ISGetLocalSize(sub_schurs->is_AEj_B[local_problem_index],&subset_size);CHKERRQ(ierr);
214     ierr = ISGetIndices(sub_schurs->is_AEj_B[local_problem_index],&idxs);CHKERRQ(ierr);
215     /* subset indices in local numbering */
216     ierr = PetscMemcpy(all_local_idx_N+local_size,idxs,subset_size*sizeof(PetscInt));CHKERRQ(ierr);
217     ierr = ISRestoreIndices(sub_schurs->is_AEj_B[local_problem_index],&idxs);CHKERRQ(ierr);
218     for (j=0;j<subset_size;j++) nnz[local_size+j] = subset_size;
219     local_size += subset_size;
220   }
221 
222   /* subset indices in local boundary numbering */
223   ierr = ISGlobalToLocalMappingApply(sub_schurs->BtoNmap,IS_GTOLM_DROP,local_size,all_local_idx_N,&subset_size,all_local_idx_B);CHKERRQ(ierr);
224   if (subset_size != local_size) {
225     SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Error in sub_schurs serial (BtoNmap)! %d != %d\n",subset_size,local_size);
226   }
227   ierr = ISCreateGeneral(PETSC_COMM_SELF,local_size,all_local_idx_B,PETSC_OWN_POINTER,&sub_schurs->is_Ej_all);CHKERRQ(ierr);
228 
229   /* Number dofs on all subsets (parallel) and sort numbering */
230   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);
231   ierr = PetscMalloc1(local_size,&all_permutation_G);CHKERRQ(ierr);
232   for (i=0;i<local_size;i++) {
233     all_permutation_G[i]=i;
234   }
235   ierr = PetscSortIntWithPermutation(local_size,all_local_idx_G,all_permutation_G);CHKERRQ(ierr);
236 
237   /* Local matrix of all local Schur on subsets */
238   ierr = MatCreate(PETSC_COMM_SELF,&sub_schurs->S_Ej_all);CHKERRQ(ierr);
239   ierr = MatSetSizes(sub_schurs->S_Ej_all,PETSC_DECIDE,PETSC_DECIDE,local_size,local_size);CHKERRQ(ierr);
240   ierr = MatSetType(sub_schurs->S_Ej_all,MATAIJ);CHKERRQ(ierr);
241   ierr = MatSeqAIJSetPreallocation(sub_schurs->S_Ej_all,0,nnz);CHKERRQ(ierr);
242   ierr = PetscFree(nnz);CHKERRQ(ierr);
243 
244   if (implicit_schurs) {
245     PetscScalar *fill_vals;
246     PetscInt    *dummy_idx;
247 
248     ierr = MatSetOption(sub_schurs->S_Ej_all,MAT_ROW_ORIENTED,PETSC_FALSE);CHKERRQ(ierr);
249 
250     /* Work arrays */
251     ierr = PetscMalloc2(max_subset_size,&dummy_idx,max_subset_size*max_subset_size,&fill_vals);CHKERRQ(ierr);
252 
253     /* Loop on local problems to compute Schur complements explicitly (TODO; optimize)*/
254     local_size = 0;
255     for (i=0;i<sub_schurs->n_subs_seq;i++) {
256       Vec work1,work2;
257       PetscInt j,local_problem_index = sub_schurs->index_sequential[i];
258 
259       ierr = MatCreateVecs(sub_schurs->S_Ej[i],&work1,&work2);CHKERRQ(ierr);
260       ierr = ISGetLocalSize(sub_schurs->is_AEj_B[local_problem_index],&subset_size);CHKERRQ(ierr);
261       /* local Schur */
262       for (j=0;j<subset_size;j++) {
263         ierr = VecSet(work1,0.0);CHKERRQ(ierr);
264         ierr = VecSetValue(work1,j,1.0,INSERT_VALUES);CHKERRQ(ierr);
265         ierr = VecPlaceArray(work2,&fill_vals[j*subset_size]);CHKERRQ(ierr);
266         ierr = MatMult(sub_schurs->S_Ej[local_problem_index],work1,work2);CHKERRQ(ierr);
267         ierr = VecResetArray(work2);CHKERRQ(ierr);
268       }
269       for (j=0;j<subset_size;j++) {
270         dummy_idx[j]=local_size+j;
271       }
272       ierr = MatSetValues(sub_schurs->S_Ej_all,subset_size,dummy_idx,subset_size,dummy_idx,fill_vals,INSERT_VALUES);CHKERRQ(ierr);
273       local_size += subset_size;
274       ierr = VecDestroy(&work1);CHKERRQ(ierr);
275       ierr = VecDestroy(&work2);CHKERRQ(ierr);
276     }
277     ierr = PetscFree2(dummy_idx,fill_vals);CHKERRQ(ierr);
278   }
279   ierr = MatAssemblyBegin(sub_schurs->S_Ej_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
280   ierr = MatAssemblyEnd(sub_schurs->S_Ej_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
281 
282   /* Global matrix of all assembled Schur on subsets */
283   ierr = ISLocalToGlobalMappingCreate(PetscObjectComm((PetscObject)sub_schurs->l2gmap),1,local_size,all_local_idx_G,PETSC_COPY_VALUES,&l2gmap_subsets);CHKERRQ(ierr);
284   ierr = MatCreateIS(PetscObjectComm((PetscObject)sub_schurs->l2gmap),1,PETSC_DECIDE,PETSC_DECIDE,global_size,global_size,l2gmap_subsets,&work_mat);CHKERRQ(ierr);
285   ierr = ISLocalToGlobalMappingDestroy(&l2gmap_subsets);CHKERRQ(ierr);
286   ierr = MatISSetLocalMat(work_mat,sub_schurs->S_Ej_all);CHKERRQ(ierr);
287   ierr = MatISGetMPIXAIJ(work_mat,MAT_INITIAL_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
288   ierr = MatDestroy(&work_mat);CHKERRQ(ierr);
289 
290   /* Get local part of (\sum_j S_Ej) */
291   for (i=0;i<local_size;i++) {
292     all_local_idx_N[i] = all_local_idx_G[all_permutation_G[i]];
293   }
294   ierr = ISCreateGeneral(PetscObjectComm((PetscObject)sub_schurs->l2gmap),local_size,all_local_idx_N,PETSC_OWN_POINTER,&temp_is);CHKERRQ(ierr);
295   ierr = MatGetSubMatrices(global_schur_subsets,1,&temp_is,&temp_is,MAT_INITIAL_MATRIX,&submat_global_schur_subsets);CHKERRQ(ierr);
296   ierr = MatDestroy(&global_schur_subsets);CHKERRQ(ierr);
297   ierr = ISDestroy(&temp_is);CHKERRQ(ierr);
298   for (i=0;i<local_size;i++) {
299     all_local_idx_G[all_permutation_G[i]] = i;
300   }
301   ierr = ISCreateGeneral(PETSC_COMM_SELF,local_size,all_local_idx_G,PETSC_OWN_POINTER,&temp_is);CHKERRQ(ierr);
302   ierr = ISSetPermutation(temp_is);CHKERRQ(ierr);
303   ierr = MatPermute(submat_global_schur_subsets[0],temp_is,temp_is,&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
304   ierr = MatDestroyMatrices(1,&submat_global_schur_subsets);CHKERRQ(ierr);
305   ierr = ISDestroy(&temp_is);CHKERRQ(ierr);
306   ierr = PetscFree(all_permutation_G);CHKERRQ(ierr);
307   PetscFunctionReturn(0);
308 }
309 
310 #undef __FUNCT__
311 #define __FUNCT__ "PCBDDCSubSchursInit"
312 PetscErrorCode PCBDDCSubSchursInit(PCBDDCSubSchurs sub_schurs, Mat A, Mat S, IS is_I, IS is_B, PCBDDCGraph graph, ISLocalToGlobalMapping BtoNmap, PetscInt seqthreshold)
313 {
314   IS                  *faces,*edges,*all_cc;
315   PetscInt            *index_sequential,*index_parallel;
316   PetscInt            *auxlocal_sequential,*auxlocal_parallel;
317   PetscInt            *auxglobal_sequential,*auxglobal_parallel;
318   PetscInt            *auxmapping;//,*idxs;
319   PetscInt            i,max_subset_size;
320   PetscInt            n_sequential_problems,n_local_sequential_problems,n_parallel_problems,n_local_parallel_problems;
321   PetscInt            n_faces,n_edges,n_all_cc;
322   PetscBool           is_sorted;
323   PetscErrorCode  ierr;
324 
325   PetscFunctionBegin;
326   ierr = ISSorted(is_I,&is_sorted);CHKERRQ(ierr);
327   if (!is_sorted) {
328     SETERRQ(PetscObjectComm((PetscObject)is_I),PETSC_ERR_PLIB,"IS for I dofs should be shorted");
329   }
330   ierr = ISSorted(is_B,&is_sorted);CHKERRQ(ierr);
331   if (!is_sorted) {
332     SETERRQ(PetscObjectComm((PetscObject)is_B),PETSC_ERR_PLIB,"IS for B dofs should be shorted");
333   }
334 
335   /* reset any previous data */
336   ierr = PCBDDCSubSchursReset(sub_schurs);CHKERRQ(ierr);
337 
338   /* get index sets for faces and edges */
339   ierr = PCBDDCGraphGetCandidatesIS(graph,&n_faces,&faces,&n_edges,&edges,NULL);CHKERRQ(ierr);
340   n_all_cc = n_faces+n_edges;
341   ierr = PetscMalloc1(n_all_cc,&all_cc);CHKERRQ(ierr);
342   for (i=0;i<n_faces;i++) {
343     all_cc[i] = faces[i];
344   }
345   for (i=0;i<n_edges;i++) {
346     all_cc[n_faces+i] = edges[i];
347   }
348   ierr = PetscFree(faces);CHKERRQ(ierr);
349   ierr = PetscFree(edges);CHKERRQ(ierr);
350 
351   /* map interface's subsets */
352   max_subset_size = 0;
353   for (i=0;i<n_all_cc;i++) {
354     PetscInt subset_size;
355     ierr = ISGetLocalSize(all_cc[i],&subset_size);CHKERRQ(ierr);
356     max_subset_size = PetscMax(max_subset_size,subset_size);
357   }
358   ierr = PetscMalloc1(max_subset_size,&auxmapping);CHKERRQ(ierr);
359   ierr = PetscMalloc2(graph->ncc,&auxlocal_sequential,
360                       graph->ncc,&auxlocal_parallel);CHKERRQ(ierr);
361   ierr = PetscMalloc2(graph->ncc,&index_sequential,
362                       graph->ncc,&index_parallel);CHKERRQ(ierr);
363 
364   /* if threshold is negative, uses all sequential problems */
365   if (seqthreshold < 0) seqthreshold = max_subset_size;
366 
367   /* determine which problem has to be solved in parallel or sequentially */
368   n_local_sequential_problems = 0;
369   n_local_parallel_problems = 0;
370   for (i=0;i<n_all_cc;i++) {
371     PetscInt       subset_size,j,min_loc = 0;
372     const PetscInt *idxs;
373 
374     ierr = ISGetLocalSize(all_cc[i],&subset_size);CHKERRQ(ierr);
375     ierr = ISGetIndices(all_cc[i],&idxs);CHKERRQ(ierr);
376     ierr = ISLocalToGlobalMappingApply(graph->l2gmap,subset_size,idxs,auxmapping);CHKERRQ(ierr);
377     for (j=1;j<subset_size;j++) {
378       if (auxmapping[j]<auxmapping[min_loc]) {
379         min_loc = j;
380       }
381     }
382     if (subset_size > seqthreshold) {
383       index_parallel[n_local_parallel_problems] = i;
384       auxlocal_parallel[n_local_parallel_problems] = idxs[min_loc];
385       n_local_parallel_problems++;
386     } else {
387       index_sequential[n_local_sequential_problems] = i;
388       auxlocal_sequential[n_local_sequential_problems] = idxs[min_loc];
389       n_local_sequential_problems++;
390     }
391     ierr = ISRestoreIndices(all_cc[i],&idxs);CHKERRQ(ierr);
392   }
393 
394   /* Number parallel problems */
395   auxglobal_parallel = 0;
396   ierr = PCBDDCSubsetNumbering(PetscObjectComm((PetscObject)graph->l2gmap),graph->l2gmap,n_local_parallel_problems,auxlocal_parallel,PETSC_NULL,&n_parallel_problems,&auxglobal_parallel);CHKERRQ(ierr);
397 
398   /* Number sequential problems */
399   auxglobal_sequential = 0;
400   ierr = PCBDDCSubsetNumbering(PetscObjectComm((PetscObject)graph->l2gmap),graph->l2gmap,n_local_sequential_problems,auxlocal_sequential,PETSC_NULL,&n_sequential_problems,&auxglobal_sequential);CHKERRQ(ierr);
401 
402   /* update info in sub_schurs */
403   if (A) {
404     ierr = PetscObjectReference((PetscObject)A);CHKERRQ(ierr);
405     sub_schurs->A = A;
406   }
407   ierr = PetscObjectReference((PetscObject)S);CHKERRQ(ierr);
408   sub_schurs->S = S;
409   ierr = PetscObjectReference((PetscObject)is_I);CHKERRQ(ierr);
410   sub_schurs->is_I = is_I;
411   ierr = PetscObjectReference((PetscObject)is_B);CHKERRQ(ierr);
412   sub_schurs->is_B = is_B;
413   ierr = PetscObjectReference((PetscObject)graph->l2gmap);CHKERRQ(ierr);
414   sub_schurs->l2gmap = graph->l2gmap;
415   ierr = PetscObjectReference((PetscObject)BtoNmap);CHKERRQ(ierr);
416   sub_schurs->BtoNmap = BtoNmap;
417   sub_schurs->n_subs_seq = n_local_sequential_problems;
418   sub_schurs->n_subs_par = n_local_parallel_problems;
419   sub_schurs->n_subs_seq_g = n_sequential_problems;
420   sub_schurs->n_subs_par_g = n_parallel_problems;
421   sub_schurs->n_subs = sub_schurs->n_subs_seq + sub_schurs->n_subs_par;
422   sub_schurs->is_subs = all_cc;
423   sub_schurs->index_sequential = index_sequential;
424   sub_schurs->index_parallel = index_parallel;
425   sub_schurs->auxglobal_sequential = auxglobal_sequential;
426   sub_schurs->auxglobal_parallel = auxglobal_parallel;
427 
428   /* free workspace */
429   ierr = PetscFree(auxmapping);CHKERRQ(ierr);
430   ierr = PetscFree2(auxlocal_sequential,auxlocal_parallel);CHKERRQ(ierr);
431 
432   PetscFunctionReturn(0);
433 }
434 
435 #undef __FUNCT__
436 #define __FUNCT__ "PCBDDCSubSchursCreate"
437 PetscErrorCode PCBDDCSubSchursCreate(PCBDDCSubSchurs *sub_schurs)
438 {
439   PCBDDCSubSchurs schurs_ctx;
440   PetscErrorCode  ierr;
441 
442   PetscFunctionBegin;
443   ierr = PetscNew(&schurs_ctx);CHKERRQ(ierr);
444   schurs_ctx->n_subs = 0;
445   *sub_schurs = schurs_ctx;
446   PetscFunctionReturn(0);
447 }
448 
449 #undef __FUNCT__
450 #define __FUNCT__ "PCBDDCSubSchursDestroy"
451 PetscErrorCode PCBDDCSubSchursDestroy(PCBDDCSubSchurs *sub_schurs)
452 {
453   PetscErrorCode ierr;
454 
455   PetscFunctionBegin;
456   ierr = PCBDDCSubSchursReset(*sub_schurs);CHKERRQ(ierr);
457   ierr = PetscFree(*sub_schurs);CHKERRQ(ierr);
458   PetscFunctionReturn(0);
459 }
460 
461 #undef __FUNCT__
462 #define __FUNCT__ "PCBDDCSubSchursReset"
463 PetscErrorCode PCBDDCSubSchursReset(PCBDDCSubSchurs sub_schurs)
464 {
465   PetscInt       i;
466   PetscErrorCode ierr;
467 
468   PetscFunctionBegin;
469   ierr = MatDestroy(&sub_schurs->A);CHKERRQ(ierr);
470   ierr = MatDestroy(&sub_schurs->S);CHKERRQ(ierr);
471   ierr = ISDestroy(&sub_schurs->is_I);CHKERRQ(ierr);
472   ierr = ISDestroy(&sub_schurs->is_B);CHKERRQ(ierr);
473   ierr = ISLocalToGlobalMappingDestroy(&sub_schurs->l2gmap);CHKERRQ(ierr);
474   ierr = ISLocalToGlobalMappingDestroy(&sub_schurs->BtoNmap);CHKERRQ(ierr);
475   ierr = MatDestroy(&sub_schurs->S_Ej_all);CHKERRQ(ierr);
476   ierr = MatDestroy(&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
477   ierr = ISDestroy(&sub_schurs->is_Ej_all);CHKERRQ(ierr);
478   for (i=0;i<sub_schurs->n_subs;i++) {
479     ierr = ISDestroy(&sub_schurs->is_subs[i]);CHKERRQ(ierr);
480     ierr = ISDestroy(&sub_schurs->is_AEj_I[i]);CHKERRQ(ierr);
481     ierr = ISDestroy(&sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
482     ierr = MatDestroy(&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
483     //ierr = VecDestroy(&sub_schurs->work1[i]);CHKERRQ(ierr);
484     //ierr = VecDestroy(&sub_schurs->work2[i]);CHKERRQ(ierr);
485   }
486   if (sub_schurs->n_subs) {
487     ierr = PetscFree(sub_schurs->is_subs);CHKERRQ(ierr);
488     ierr = PetscFree5(sub_schurs->is_AEj_I,sub_schurs->is_AEj_B,sub_schurs->S_Ej,sub_schurs->work1,sub_schurs->work2);CHKERRQ(ierr);
489     ierr = PetscFree2(sub_schurs->index_sequential,sub_schurs->index_parallel);CHKERRQ(ierr);
490     ierr = PetscFree(sub_schurs->auxglobal_sequential);CHKERRQ(ierr);
491     ierr = PetscFree(sub_schurs->auxglobal_parallel);CHKERRQ(ierr);
492   }
493   sub_schurs->n_subs = 0;
494   PetscFunctionReturn(0);
495 }
496 
497 #undef __FUNCT__
498 #define __FUNCT__ "PCBDDCAdjGetNextLayer_Private"
499 PETSC_STATIC_INLINE PetscErrorCode PCBDDCAdjGetNextLayer_Private(PetscInt* queue_tip,PetscInt n_prev,PetscBT touched,PetscInt* xadj,PetscInt* adjncy,PetscInt* n_added)
500 {
501   PetscInt       i,j,n;
502   PetscErrorCode ierr;
503 
504   PetscFunctionBegin;
505   n = 0;
506   for (i=-n_prev;i<0;i++) {
507     PetscInt start_dof = queue_tip[i];
508     for (j=xadj[start_dof];j<xadj[start_dof+1];j++) {
509       PetscInt dof = adjncy[j];
510       if (!PetscBTLookup(touched,dof)) {
511         ierr = PetscBTSet(touched,dof);CHKERRQ(ierr);
512         queue_tip[n] = dof;
513         n++;
514       }
515     }
516   }
517   *n_added = n;
518   PetscFunctionReturn(0);
519 }
520 
521 #undef __FUNCT__
522 #define __FUNCT__ "PCBDDCSubSchursSetUp"
523 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)
524 {
525   Mat                    A_II,A_IB,A_BI,A_BB;
526   Mat                    AE_II,*AE_IE,*AE_EI,*AE_EE;
527   IS                     is_I,*is_subset_B;
528   ISLocalToGlobalMapping BtoNmap;
529   PetscInt               i;
530   PetscBool              is_sorted;
531   PetscErrorCode         ierr;
532 
533   PetscFunctionBegin;
534   ierr = ISSorted(is_A_I,&is_sorted);CHKERRQ(ierr);
535   if (!is_sorted) {
536     SETERRQ(PetscObjectComm((PetscObject)is_A_I),PETSC_ERR_PLIB,"IS for I dofs should be shorted");
537   }
538   ierr = ISSorted(is_A_B,&is_sorted);CHKERRQ(ierr);
539   if (!is_sorted) {
540     SETERRQ(PetscObjectComm((PetscObject)is_A_B),PETSC_ERR_PLIB,"IS for B dofs should be shorted");
541   }
542 
543   /* get Schur complement matrices */
544   ierr = MatSchurComplementGetSubMatrices(S,&A_II,NULL,&A_IB,&A_BI,&A_BB);CHKERRQ(ierr);
545 
546   /* allocate space for schur complements */
547   ierr = PetscMalloc5(sub_schurs->n_subs,&sub_schurs->is_AEj_I,
548                       sub_schurs->n_subs,&sub_schurs->is_AEj_B,
549                       sub_schurs->n_subs,&sub_schurs->S_Ej,
550                       sub_schurs->n_subs,&sub_schurs->work1,
551                       sub_schurs->n_subs,&sub_schurs->work2);CHKERRQ(ierr);
552   ierr = PetscMalloc4(ncc,&is_subset_B,ncc,&AE_IE,ncc,&AE_EI,ncc,&AE_EE);CHKERRQ(ierr);
553   sub_schurs->n_subs = ncc;
554 
555   /* maps */
556   if (sub_schurs->n_subs && nlayers >= 0 && xadj != NULL && adjncy != NULL) { /* Interior problems can be different from the original one */
557     ISLocalToGlobalMapping ItoNmap;
558     PetscBT                touched;
559     const PetscInt*        idx_B;
560     PetscInt               n_I,n_B,n_local_dofs,n_prev_added,j,layer,*local_numbering;
561 
562     /* get sizes */
563     ierr = ISGetLocalSize(is_A_I,&n_I);CHKERRQ(ierr);
564     ierr = ISGetLocalSize(is_A_B,&n_B);CHKERRQ(ierr);
565 
566     ierr = ISLocalToGlobalMappingCreateIS(is_A_I,&ItoNmap);CHKERRQ(ierr);
567     ierr = PetscMalloc1(n_I+n_B,&local_numbering);CHKERRQ(ierr);
568     ierr = PetscBTCreate(n_I+n_B,&touched);CHKERRQ(ierr);
569     ierr = PetscBTMemzero(n_I+n_B,touched);CHKERRQ(ierr);
570 
571     /* all boundary dofs must be skipped when adding layers */
572     ierr = ISGetIndices(is_A_B,&idx_B);CHKERRQ(ierr);
573     for (j=0;j<n_B;j++) {
574       ierr = PetscBTSet(touched,idx_B[j]);CHKERRQ(ierr);
575     }
576     ierr = PetscMemcpy(local_numbering,idx_B,n_B*sizeof(PetscInt));CHKERRQ(ierr);
577     ierr = ISRestoreIndices(is_A_B,&idx_B);CHKERRQ(ierr);
578 
579     /* add next layers of dofs */
580     n_local_dofs = n_B;
581     n_prev_added = n_B;
582     for (layer=0;layer<nlayers;layer++) {
583       PetscInt n_added;
584       if (n_local_dofs == n_I+n_B) break;
585       if (n_local_dofs > n_I+n_B) {
586         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);
587       }
588       ierr = PCBDDCAdjGetNextLayer_Private(local_numbering+n_local_dofs,n_prev_added,touched,xadj,adjncy,&n_added);CHKERRQ(ierr);
589       n_prev_added = n_added;
590       n_local_dofs += n_added;
591       if (!n_added) break;
592     }
593     ierr = PetscBTDestroy(&touched);CHKERRQ(ierr);
594 
595     /* IS for I dofs in original numbering and in I numbering */
596     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);
597     ierr = PetscFree(local_numbering);CHKERRQ(ierr);
598     ierr = ISSort(sub_schurs->is_AEj_I[0]);CHKERRQ(ierr);
599     ierr = ISGlobalToLocalMappingApplyIS(ItoNmap,IS_GTOLM_DROP,sub_schurs->is_AEj_I[0],&is_I);CHKERRQ(ierr);
600     ierr = ISLocalToGlobalMappingDestroy(&ItoNmap);CHKERRQ(ierr);
601 
602     /* II block */
603     ierr = MatGetSubMatrix(A_II,is_I,is_I,MAT_INITIAL_MATRIX,&AE_II);CHKERRQ(ierr);
604   } else {
605     PetscInt n_I;
606 
607     /* IS for I dofs in original numbering */
608     ierr = PetscObjectReference((PetscObject)is_A_I);CHKERRQ(ierr);
609     sub_schurs->is_AEj_I[0] = is_A_I;
610 
611     /* IS for I dofs in I numbering (strided 1) */
612     ierr = ISGetSize(is_A_I,&n_I);CHKERRQ(ierr);
613     ierr = ISCreateStride(PetscObjectComm((PetscObject)is_A_I),n_I,0,1,&is_I);CHKERRQ(ierr);
614 
615     /* II block is the same */
616     ierr = PetscObjectReference((PetscObject)A_II);CHKERRQ(ierr);
617     AE_II = A_II;
618   }
619 
620   /* TODO: just for compatibility with the previous version, needs to be fixed */
621   for (i=1;i<sub_schurs->n_subs;i++) {
622     ierr = PetscObjectReference((PetscObject)sub_schurs->is_AEj_I[0]);CHKERRQ(ierr);
623     sub_schurs->is_AEj_I[i] = sub_schurs->is_AEj_I[0];
624   }
625 
626   /* subsets in original and boundary numbering */
627   ierr = ISLocalToGlobalMappingCreateIS(is_A_B,&BtoNmap);CHKERRQ(ierr);
628   for (i=0;i<sub_schurs->n_subs;i++) {
629     ierr = ISDuplicate(is_cc[i],&sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
630     ierr = ISSort(sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
631     ierr = ISGlobalToLocalMappingApplyIS(BtoNmap,IS_GTOLM_DROP,sub_schurs->is_AEj_B[i],&is_subset_B[i]);CHKERRQ(ierr);
632   }
633   ierr = ISLocalToGlobalMappingDestroy(&BtoNmap);CHKERRQ(ierr);
634 
635   /* EE block */
636   for (i=0;i<sub_schurs->n_subs;i++) {
637     ierr = MatGetSubMatrix(A_BB,is_subset_B[i],is_subset_B[i],MAT_INITIAL_MATRIX,&AE_EE[i]);CHKERRQ(ierr);
638   }
639   /* IE block */
640   for (i=0;i<sub_schurs->n_subs;i++) {
641     ierr = MatGetSubMatrix(A_IB,is_I,is_subset_B[i],MAT_INITIAL_MATRIX,&AE_IE[i]);CHKERRQ(ierr);
642   }
643   /* EI block */
644   for (i=0;i<sub_schurs->n_subs;i++) {
645     ierr = MatGetSubMatrix(A_BI,is_subset_B[i],is_I,MAT_INITIAL_MATRIX,&AE_EI[i]);CHKERRQ(ierr);
646   }
647 
648   /* setup Schur complements on subset */
649   for (i=0;i<sub_schurs->n_subs;i++) {
650     ierr = MatCreateSchurComplement(AE_II,AE_II,AE_IE[i],AE_EI[i],AE_EE[i],&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
651     ierr = MatCreateVecs(sub_schurs->S_Ej[i],&sub_schurs->work1[i],&sub_schurs->work2[i]);CHKERRQ(ierr);
652     if (AE_II == A_II) { /* we can reuse the same ksp */
653       KSP ksp;
654       ierr = MatSchurComplementGetKSP(S,&ksp);CHKERRQ(ierr);
655       ierr = MatSchurComplementSetKSP(sub_schurs->S_Ej[i],ksp);CHKERRQ(ierr);
656     } else { /* build new ksp object which inherits ksp and pc types from the original one */
657       KSP      origksp,schurksp;
658       PC       origpc,schurpc;
659       KSPType  ksp_type;
660       PCType   pc_type;
661       PetscInt n_internal;
662 
663       ierr = MatSchurComplementGetKSP(S,&origksp);CHKERRQ(ierr);
664       ierr = MatSchurComplementGetKSP(sub_schurs->S_Ej[i],&schurksp);CHKERRQ(ierr);
665       ierr = KSPGetType(origksp,&ksp_type);CHKERRQ(ierr);
666       ierr = KSPSetType(schurksp,ksp_type);CHKERRQ(ierr);
667       ierr = KSPGetPC(schurksp,&schurpc);CHKERRQ(ierr);
668       ierr = KSPGetPC(origksp,&origpc);CHKERRQ(ierr);
669       ierr = PCGetType(origpc,&pc_type);CHKERRQ(ierr);
670       ierr = PCSetType(schurpc,pc_type);CHKERRQ(ierr);
671       ierr = ISGetSize(is_I,&n_internal);CHKERRQ(ierr);
672       if (n_internal) { /* UMFPACK gives error with 0 sized problems */
673         MatSolverPackage solver=NULL;
674         ierr = PCFactorGetMatSolverPackage(origpc,(const MatSolverPackage*)&solver);CHKERRQ(ierr);
675         if (solver) {
676           ierr = PCFactorSetMatSolverPackage(schurpc,solver);CHKERRQ(ierr);
677         }
678       }
679       ierr = KSPSetUp(schurksp);CHKERRQ(ierr);
680     }
681   }
682   /* free */
683   ierr = ISDestroy(&is_I);CHKERRQ(ierr);
684   ierr = MatDestroy(&AE_II);CHKERRQ(ierr);
685   for (i=0;i<sub_schurs->n_subs;i++) {
686     ierr = MatDestroy(&AE_EE[i]);CHKERRQ(ierr);
687     ierr = MatDestroy(&AE_IE[i]);CHKERRQ(ierr);
688     ierr = MatDestroy(&AE_EI[i]);CHKERRQ(ierr);
689     ierr = ISDestroy(&is_subset_B[i]);CHKERRQ(ierr);
690   }
691   ierr = PetscFree4(is_subset_B,AE_IE,AE_EI,AE_EE);CHKERRQ(ierr);
692   PetscFunctionReturn(0);
693 }
694