xref: /petsc/src/ksp/pc/impls/bddc/bddcschurs.c (revision 883469d828b616a25ec292054b69b8df0fbc2384)
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                    S_all,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;
16   PetscInt               i,subset_size,max_subset_size;
17   PetscInt               extra,local_size,global_size;
18   PetscErrorCode         ierr;
19 
20   PetscFunctionBegin;
21 
22   /* allocate space for schur complements */
23   ierr = PetscMalloc4(sub_schurs->n_subs,&sub_schurs->is_AEj_B,
24                       sub_schurs->n_subs,&sub_schurs->S_Ej,
25                       sub_schurs->n_subs,&sub_schurs->work1,
26                       sub_schurs->n_subs,&sub_schurs->work2);CHKERRQ(ierr);
27 
28   /* get Schur complement matrices */
29   if (!sub_schurs->use_mumps) {
30     ierr = MatSchurComplementGetSubMatrices(sub_schurs->S,&A_II,NULL,&A_IB,&A_BI,&A_BB);CHKERRQ(ierr);
31     ierr = PetscMalloc4(sub_schurs->n_subs,&is_subset_B,
32                         sub_schurs->n_subs,&AE_IE,
33                         sub_schurs->n_subs,&AE_EI,
34                         sub_schurs->n_subs,&AE_EE);CHKERRQ(ierr);
35   }
36 
37   /* determine interior problems */
38   if (nlayers >= 0 && xadj != NULL && adjncy != NULL) { /* Interior problems can be different from the original one */
39     PetscBT                touched;
40     const PetscInt*        idx_B;
41     PetscInt               n_I,n_B,n_local_dofs,n_prev_added,j,layer,*local_numbering;
42 
43     /* get sizes */
44     ierr = ISGetLocalSize(sub_schurs->is_I,&n_I);CHKERRQ(ierr);
45     ierr = ISGetLocalSize(sub_schurs->is_B,&n_B);CHKERRQ(ierr);
46 
47     ierr = PetscMalloc1(n_I+n_B,&local_numbering);CHKERRQ(ierr);
48     ierr = PetscBTCreate(n_I+n_B,&touched);CHKERRQ(ierr);
49     ierr = PetscBTMemzero(n_I+n_B,touched);CHKERRQ(ierr);
50 
51     /* all boundary dofs must be skipped when adding layers */
52     ierr = ISGetIndices(sub_schurs->is_B,&idx_B);CHKERRQ(ierr);
53     for (j=0;j<n_B;j++) {
54       ierr = PetscBTSet(touched,idx_B[j]);CHKERRQ(ierr);
55     }
56     ierr = PetscMemcpy(local_numbering,idx_B,n_B*sizeof(PetscInt));CHKERRQ(ierr);
57     ierr = ISRestoreIndices(sub_schurs->is_B,&idx_B);CHKERRQ(ierr);
58 
59     /* add prescribed number of layers of dofs */
60     n_local_dofs = n_B;
61     n_prev_added = n_B;
62     for (layer=0;layer<nlayers;layer++) {
63       PetscInt n_added;
64       if (n_local_dofs == n_I+n_B) break;
65       if (n_local_dofs > n_I+n_B) {
66         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);
67       }
68       ierr = PCBDDCAdjGetNextLayer_Private(local_numbering+n_local_dofs,n_prev_added,touched,xadj,adjncy,&n_added);CHKERRQ(ierr);
69       n_prev_added = n_added;
70       n_local_dofs += n_added;
71       if (!n_added) break;
72     }
73     ierr = PetscBTDestroy(&touched);CHKERRQ(ierr);
74 
75     /* IS for I layer dofs in original numbering */
76     ierr = ISCreateGeneral(PetscObjectComm((PetscObject)sub_schurs->is_I),n_local_dofs-n_B,local_numbering+n_B,PETSC_COPY_VALUES,&sub_schurs->is_I_layer);CHKERRQ(ierr);
77     ierr = PetscFree(local_numbering);CHKERRQ(ierr);
78     ierr = ISSort(sub_schurs->is_I_layer);CHKERRQ(ierr);
79     /* IS for I layer dofs in I numbering */
80     if (!sub_schurs->use_mumps) {
81       ISLocalToGlobalMapping ItoNmap;
82       ierr = ISLocalToGlobalMappingCreateIS(sub_schurs->is_I,&ItoNmap);CHKERRQ(ierr);
83       ierr = ISGlobalToLocalMappingApplyIS(ItoNmap,IS_GTOLM_DROP,sub_schurs->is_I_layer,&is_I);CHKERRQ(ierr);
84       ierr = ISLocalToGlobalMappingDestroy(&ItoNmap);CHKERRQ(ierr);
85 
86       /* II block */
87       ierr = MatGetSubMatrix(A_II,is_I,is_I,MAT_INITIAL_MATRIX,&AE_II);CHKERRQ(ierr);
88     }
89   } else {
90     PetscInt n_I;
91 
92     /* IS for I dofs in original numbering */
93     ierr = PetscObjectReference((PetscObject)sub_schurs->is_I);CHKERRQ(ierr);
94     sub_schurs->is_I_layer = sub_schurs->is_I;
95 
96     /* IS for I dofs in I numbering (strided 1) */
97     if (!sub_schurs->use_mumps) {
98       ierr = ISGetSize(sub_schurs->is_I,&n_I);CHKERRQ(ierr);
99       ierr = ISCreateStride(PetscObjectComm((PetscObject)sub_schurs->is_I),n_I,0,1,&is_I);CHKERRQ(ierr);
100 
101       /* II block is the same */
102       ierr = PetscObjectReference((PetscObject)A_II);CHKERRQ(ierr);
103       AE_II = A_II;
104     }
105   }
106 
107   for (i=0;i<sub_schurs->n_subs;i++) {
108     ierr = ISDuplicate(sub_schurs->is_subs[i],&sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
109     ierr = ISSort(sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
110   }
111 
112   /* Get info on subset sizes and sum of all subsets sizes */
113   max_subset_size = 0;
114   local_size = 0;
115   for (i=0;i<sub_schurs->n_subs_seq;i++) {
116     PetscInt j = sub_schurs->index_sequential[i];
117     ierr = ISGetLocalSize(sub_schurs->is_AEj_B[j],&subset_size);CHKERRQ(ierr);
118     max_subset_size = PetscMax(subset_size,max_subset_size);
119     local_size += subset_size;
120   }
121 
122   /* Work arrays for local indices */
123   ierr = PetscMalloc1(local_size,&all_local_idx_B);CHKERRQ(ierr);
124   extra = 0;
125   if (sub_schurs->use_mumps) {
126     ierr = ISGetLocalSize(sub_schurs->is_I_layer,&extra);CHKERRQ(ierr);
127   }
128   ierr = PetscMalloc1(local_size+extra,&all_local_idx_N);CHKERRQ(ierr);
129   if (extra) {
130     const PetscInt *idxs;
131     ierr = ISGetIndices(sub_schurs->is_I_layer,&idxs);CHKERRQ(ierr);
132     ierr = PetscMemcpy(all_local_idx_N,idxs,extra*sizeof(PetscInt));CHKERRQ(ierr);
133     ierr = ISRestoreIndices(sub_schurs->is_I_layer,&idxs);CHKERRQ(ierr);
134   }
135   ierr = PetscMalloc1(local_size,&nnz);CHKERRQ(ierr);
136 
137   /* Get local indices in local numbering */
138   local_size = 0;
139   for (i=0;i<sub_schurs->n_subs_seq;i++) {
140     PetscInt j;
141     const    PetscInt *idxs;
142 
143     PetscInt local_problem_index = sub_schurs->index_sequential[i];
144     ierr = ISGetLocalSize(sub_schurs->is_AEj_B[local_problem_index],&subset_size);CHKERRQ(ierr);
145     ierr = ISGetIndices(sub_schurs->is_AEj_B[local_problem_index],&idxs);CHKERRQ(ierr);
146     /* subset indices in local numbering */
147     ierr = PetscMemcpy(all_local_idx_N+local_size+extra,idxs,subset_size*sizeof(PetscInt));CHKERRQ(ierr);
148     ierr = ISRestoreIndices(sub_schurs->is_AEj_B[local_problem_index],&idxs);CHKERRQ(ierr);
149     for (j=0;j<subset_size;j++) nnz[local_size+j] = subset_size;
150     local_size += subset_size;
151   }
152 
153   S_all = NULL;
154   if (!sub_schurs->use_mumps) {
155     /* subsets in original and boundary numbering */
156     for (i=0;i<sub_schurs->n_subs;i++) {
157       ierr = ISGlobalToLocalMappingApplyIS(sub_schurs->BtoNmap,IS_GTOLM_DROP,sub_schurs->is_AEj_B[i],&is_subset_B[i]);CHKERRQ(ierr);
158     }
159 
160     /* EE block */
161     for (i=0;i<sub_schurs->n_subs;i++) {
162       ierr = MatGetSubMatrix(A_BB,is_subset_B[i],is_subset_B[i],MAT_INITIAL_MATRIX,&AE_EE[i]);CHKERRQ(ierr);
163     }
164     /* IE block */
165     for (i=0;i<sub_schurs->n_subs;i++) {
166       ierr = MatGetSubMatrix(A_IB,is_I,is_subset_B[i],MAT_INITIAL_MATRIX,&AE_IE[i]);CHKERRQ(ierr);
167     }
168     /* EI block */
169     for (i=0;i<sub_schurs->n_subs;i++) {
170       ierr = MatGetSubMatrix(A_BI,is_subset_B[i],is_I,MAT_INITIAL_MATRIX,&AE_EI[i]);CHKERRQ(ierr);
171     }
172 
173     /* setup Schur complements on subset */
174     for (i=0;i<sub_schurs->n_subs;i++) {
175       ierr = MatCreateSchurComplement(AE_II,AE_II,AE_IE[i],AE_EI[i],AE_EE[i],&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
176       if (AE_II == A_II) { /* we can reuse the same ksp */
177         KSP ksp;
178         ierr = MatSchurComplementGetKSP(sub_schurs->S,&ksp);CHKERRQ(ierr);
179         ierr = MatSchurComplementSetKSP(sub_schurs->S_Ej[i],ksp);CHKERRQ(ierr);
180       } else { /* build new ksp object which inherits ksp and pc types from the original one */
181         KSP      origksp,schurksp;
182         PC       origpc,schurpc;
183         KSPType  ksp_type;
184         PCType   pc_type;
185         PetscInt n_internal;
186 
187         ierr = MatSchurComplementGetKSP(sub_schurs->S,&origksp);CHKERRQ(ierr);
188         ierr = MatSchurComplementGetKSP(sub_schurs->S_Ej[i],&schurksp);CHKERRQ(ierr);
189         ierr = KSPGetType(origksp,&ksp_type);CHKERRQ(ierr);
190         ierr = KSPSetType(schurksp,ksp_type);CHKERRQ(ierr);
191         ierr = KSPGetPC(schurksp,&schurpc);CHKERRQ(ierr);
192         ierr = KSPGetPC(origksp,&origpc);CHKERRQ(ierr);
193         ierr = PCGetType(origpc,&pc_type);CHKERRQ(ierr);
194         ierr = PCSetType(schurpc,pc_type);CHKERRQ(ierr);
195         ierr = ISGetSize(is_I,&n_internal);CHKERRQ(ierr);
196         if (n_internal) { /* UMFPACK gives error with 0 sized problems */
197           MatSolverPackage solver=NULL;
198           ierr = PCFactorGetMatSolverPackage(origpc,(const MatSolverPackage*)&solver);CHKERRQ(ierr);
199           if (solver) {
200             ierr = PCFactorSetMatSolverPackage(schurpc,solver);CHKERRQ(ierr);
201           }
202         }
203         ierr = KSPSetUp(schurksp);CHKERRQ(ierr);
204       }
205     }
206     /* free */
207     ierr = ISDestroy(&is_I);CHKERRQ(ierr);
208     ierr = MatDestroy(&AE_II);CHKERRQ(ierr);
209     for (i=0;i<sub_schurs->n_subs;i++) {
210       ierr = MatDestroy(&AE_EE[i]);CHKERRQ(ierr);
211       ierr = MatDestroy(&AE_IE[i]);CHKERRQ(ierr);
212       ierr = MatDestroy(&AE_EI[i]);CHKERRQ(ierr);
213       ierr = ISDestroy(&is_subset_B[i]);CHKERRQ(ierr);
214     }
215     ierr = PetscFree4(is_subset_B,AE_IE,AE_EI,AE_EE);CHKERRQ(ierr);
216 #if defined(PETSC_HAVE_MUMPS)
217   } else {
218     Mat           A,F;
219     IS            is_A_all;
220     PetscBool     is_symmetric;
221     PetscInt      *idxs_schur,n_I;
222 
223     /* get working mat */
224     ierr = ISGetLocalSize(sub_schurs->is_I_layer,&n_I);CHKERRQ(ierr);
225     ierr = ISCreateGeneral(PETSC_COMM_SELF,local_size+n_I,all_local_idx_N,PETSC_COPY_VALUES,&is_A_all);CHKERRQ(ierr);
226     ierr = MatGetSubMatrixUnsorted(sub_schurs->A,is_A_all,is_A_all,&A);CHKERRQ(ierr);
227     ierr = ISDestroy(&is_A_all);CHKERRQ(ierr);
228 
229     ierr = MatIsSymmetric(sub_schurs->A,0.0,&is_symmetric);CHKERRQ(ierr);
230     if (is_symmetric) {
231       ierr = MatGetFactor(A,MATSOLVERMUMPS,MAT_FACTOR_CHOLESKY,&F);CHKERRQ(ierr);
232     } else {
233       ierr = MatGetFactor(A,MATSOLVERMUMPS,MAT_FACTOR_LU,&F);CHKERRQ(ierr);
234     }
235 
236     /* subsets ordered last */
237     ierr = PetscMalloc1(local_size,&idxs_schur);CHKERRQ(ierr);
238     for (i=0;i<local_size;i++) {
239       idxs_schur[i] = n_I+i+1;
240     }
241     ierr = MatMumpsSetSchurIndices(F,local_size,idxs_schur);CHKERRQ(ierr);
242     ierr = PetscFree(idxs_schur);CHKERRQ(ierr);
243 
244     /* factorization step */
245     if (is_symmetric) {
246       ierr = MatCholeskyFactorSymbolic(F,A,NULL,NULL);CHKERRQ(ierr);
247       ierr = MatCholeskyFactorNumeric(F,A,NULL);CHKERRQ(ierr);
248     } else {
249       ierr = MatLUFactorSymbolic(F,A,NULL,NULL,NULL);CHKERRQ(ierr);
250       ierr = MatLUFactorNumeric(F,A,NULL);CHKERRQ(ierr);
251     }
252 
253     /* get explicit Schur Complement computed during numeric factorization */
254     ierr = MatMumpsGetSchurComplement(F,&S_all);CHKERRQ(ierr);
255 
256     /* free workspace */
257     ierr = MatDestroy(&A);CHKERRQ(ierr);
258     ierr = MatDestroy(&F);CHKERRQ(ierr);
259 
260     /* unused */
261     for (i=0;i<sub_schurs->n_subs;i++) {
262        sub_schurs->S_Ej[i] = 0;
263     }
264 #endif
265   }
266 
267   /* TODO: just for compatibility with the previous version, needs to be fixed */
268   for (i=0;i<sub_schurs->n_subs_par;i++) {
269     PetscInt j = sub_schurs->index_parallel[i];
270     ierr = MatCreateVecs(sub_schurs->S_Ej[j],&sub_schurs->work1[j],&sub_schurs->work2[j]);CHKERRQ(ierr);
271   }
272   for (i=0;i<sub_schurs->n_subs_seq;i++) {
273      sub_schurs->work1[sub_schurs->index_sequential[i]] = 0;
274      sub_schurs->work2[sub_schurs->index_sequential[i]] = 0;
275   }
276 
277   if (!sub_schurs->n_subs_seq_g) {
278     sub_schurs->S_Ej_all = 0;
279     sub_schurs->sum_S_Ej_all = 0;
280     sub_schurs->is_Ej_all = 0;
281     PetscFunctionReturn(0);
282   }
283 
284   /* subset indices in local boundary numbering */
285   ierr = ISGlobalToLocalMappingApply(sub_schurs->BtoNmap,IS_GTOLM_DROP,local_size,all_local_idx_N+extra,&subset_size,all_local_idx_B);CHKERRQ(ierr);
286   if (subset_size != local_size) {
287     SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Error in sub_schurs serial (BtoNmap)! %d != %d\n",subset_size,local_size);
288   }
289   ierr = ISCreateGeneral(PETSC_COMM_SELF,local_size,all_local_idx_B,PETSC_OWN_POINTER,&sub_schurs->is_Ej_all);CHKERRQ(ierr);
290 
291   /* Local matrix of all local Schur on subsets */
292   ierr = MatCreate(PETSC_COMM_SELF,&sub_schurs->S_Ej_all);CHKERRQ(ierr);
293   ierr = MatSetSizes(sub_schurs->S_Ej_all,PETSC_DECIDE,PETSC_DECIDE,local_size,local_size);CHKERRQ(ierr);
294   ierr = MatSetType(sub_schurs->S_Ej_all,MATAIJ);CHKERRQ(ierr);
295   ierr = MatSeqAIJSetPreallocation(sub_schurs->S_Ej_all,0,nnz);CHKERRQ(ierr);
296   ierr = PetscFree(nnz);CHKERRQ(ierr);
297 
298   if (!sub_schurs->use_mumps) {
299     PetscScalar *fill_vals;
300     PetscInt    *dummy_idx;
301 
302     /* Work arrays */
303     ierr = PetscMalloc2(max_subset_size,&dummy_idx,max_subset_size*max_subset_size,&fill_vals);CHKERRQ(ierr);
304 
305     /* Loop on local problems to compute Schur complements explicitly (TODO; optimize)*/
306     local_size = 0;
307     for (i=0;i<sub_schurs->n_subs_seq;i++) {
308       Vec work1,work2;
309       PetscInt j,local_problem_index = sub_schurs->index_sequential[i];
310 
311       ierr = MatCreateVecs(sub_schurs->S_Ej[local_problem_index],&work1,&work2);CHKERRQ(ierr);
312       ierr = ISGetLocalSize(sub_schurs->is_AEj_B[local_problem_index],&subset_size);CHKERRQ(ierr);
313       /* local Schur */
314       for (j=0;j<subset_size;j++) {
315         ierr = VecSet(work1,0.0);CHKERRQ(ierr);
316         ierr = VecSetValue(work1,j,1.0,INSERT_VALUES);CHKERRQ(ierr);
317         ierr = VecPlaceArray(work2,&fill_vals[j*subset_size]);CHKERRQ(ierr);
318         ierr = MatMult(sub_schurs->S_Ej[local_problem_index],work1,work2);CHKERRQ(ierr);
319         ierr = VecResetArray(work2);CHKERRQ(ierr);
320       }
321       for (j=0;j<subset_size;j++) {
322         dummy_idx[j]=local_size+j;
323       }
324       ierr = MatSetValues(sub_schurs->S_Ej_all,subset_size,dummy_idx,subset_size,dummy_idx,fill_vals,INSERT_VALUES);CHKERRQ(ierr);
325       local_size += subset_size;
326       ierr = VecDestroy(&work1);CHKERRQ(ierr);
327       ierr = VecDestroy(&work2);CHKERRQ(ierr);
328     }
329     ierr = PetscFree2(dummy_idx,fill_vals);CHKERRQ(ierr);
330   } else {
331     PetscInt    *dummy_idx,n_all;
332     PetscScalar *vals,*fill_vals;
333 
334     /* Work arrays */
335     ierr = PetscMalloc1(max_subset_size,&dummy_idx);CHKERRQ(ierr);
336     ierr = MatGetSize(S_all,&n_all,NULL);CHKERRQ(ierr);
337     ierr = MatDenseGetArray(S_all,&vals);CHKERRQ(ierr);
338     local_size = 0;
339     subset_size = 0;
340     fill_vals = vals;
341     for (i=0;i<sub_schurs->n_subs_seq;i++) {
342       PetscInt j,lpi = sub_schurs->index_sequential[i];
343 
344       fill_vals += subset_size;
345       ierr = ISGetLocalSize(sub_schurs->is_AEj_B[lpi],&subset_size);CHKERRQ(ierr);
346       for (j=0;j<subset_size;j++) {
347         dummy_idx[j]=local_size+j;
348       }
349       for (j=0;j<subset_size;j++) {
350         ierr = MatSetValues(sub_schurs->S_Ej_all,1,dummy_idx+j,subset_size,dummy_idx,fill_vals,INSERT_VALUES);CHKERRQ(ierr);
351         fill_vals += n_all;
352       }
353       local_size += subset_size;
354     }
355     ierr = MatDenseRestoreArray(S_all,&vals);CHKERRQ(ierr);
356     ierr = PetscFree(dummy_idx);CHKERRQ(ierr);
357   }
358   ierr = MatAssemblyBegin(sub_schurs->S_Ej_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
359   ierr = MatAssemblyEnd(sub_schurs->S_Ej_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
360   ierr = MatDestroy(&S_all);CHKERRQ(ierr);
361 
362   /* Global matrix of all assembled Schur on subsets */
363   ierr = PCBDDCSubsetNumbering(PetscObjectComm((PetscObject)sub_schurs->l2gmap),sub_schurs->l2gmap,local_size,all_local_idx_N+extra,PETSC_NULL,&global_size,&all_local_idx_G);CHKERRQ(ierr);
364   ierr = ISLocalToGlobalMappingCreate(PetscObjectComm((PetscObject)sub_schurs->l2gmap),1,local_size,all_local_idx_G,PETSC_COPY_VALUES,&l2gmap_subsets);CHKERRQ(ierr);
365   ierr = MatCreateIS(PetscObjectComm((PetscObject)sub_schurs->l2gmap),1,PETSC_DECIDE,PETSC_DECIDE,global_size,global_size,l2gmap_subsets,&work_mat);CHKERRQ(ierr);
366   ierr = ISLocalToGlobalMappingDestroy(&l2gmap_subsets);CHKERRQ(ierr);
367   ierr = MatISSetLocalMat(work_mat,sub_schurs->S_Ej_all);CHKERRQ(ierr);
368   ierr = MatISGetMPIXAIJ(work_mat,MAT_INITIAL_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
369   ierr = MatDestroy(&work_mat);CHKERRQ(ierr);
370 
371   /* Get local part of (\sum_j S_Ej) */
372   ierr = PetscFree(all_local_idx_N);CHKERRQ(ierr);
373   ierr = ISCreateGeneral(PetscObjectComm((PetscObject)sub_schurs->l2gmap),local_size,all_local_idx_G,PETSC_OWN_POINTER,&temp_is);CHKERRQ(ierr);
374   ierr = MatGetSubMatrixUnsorted(global_schur_subsets,temp_is,temp_is,&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
375   ierr = MatDestroy(&global_schur_subsets);CHKERRQ(ierr);
376   ierr = ISDestroy(&temp_is);CHKERRQ(ierr);
377   PetscFunctionReturn(0);
378 }
379 
380 #undef __FUNCT__
381 #define __FUNCT__ "PCBDDCSubSchursInit"
382 PetscErrorCode PCBDDCSubSchursInit(PCBDDCSubSchurs sub_schurs, Mat A, Mat S, IS is_I, IS is_B, PCBDDCGraph graph, ISLocalToGlobalMapping BtoNmap, PetscInt seqthreshold)
383 {
384   IS                  *faces,*edges,*all_cc;
385   PetscInt            *index_sequential,*index_parallel;
386   PetscInt            *auxlocal_sequential,*auxlocal_parallel;
387   PetscInt            *auxglobal_sequential,*auxglobal_parallel;
388   PetscInt            *auxmapping;//,*idxs;
389   PetscInt            i,max_subset_size;
390   PetscInt            n_sequential_problems,n_local_sequential_problems,n_parallel_problems,n_local_parallel_problems;
391   PetscInt            n_faces,n_edges,n_all_cc;
392   PetscBool           is_sorted;
393   PetscErrorCode  ierr;
394 
395   PetscFunctionBegin;
396   ierr = ISSorted(is_I,&is_sorted);CHKERRQ(ierr);
397   if (!is_sorted) {
398     SETERRQ(PetscObjectComm((PetscObject)is_I),PETSC_ERR_PLIB,"IS for I dofs should be shorted");
399   }
400   ierr = ISSorted(is_B,&is_sorted);CHKERRQ(ierr);
401   if (!is_sorted) {
402     SETERRQ(PetscObjectComm((PetscObject)is_B),PETSC_ERR_PLIB,"IS for B dofs should be shorted");
403   }
404 
405   /* reset any previous data */
406   ierr = PCBDDCSubSchursReset(sub_schurs);CHKERRQ(ierr);
407 
408   /* get index sets for faces and edges */
409   ierr = PCBDDCGraphGetCandidatesIS(graph,&n_faces,&faces,&n_edges,&edges,NULL);CHKERRQ(ierr);
410   n_all_cc = n_faces+n_edges;
411   ierr = PetscMalloc1(n_all_cc,&all_cc);CHKERRQ(ierr);
412   for (i=0;i<n_faces;i++) {
413     all_cc[i] = faces[i];
414   }
415   for (i=0;i<n_edges;i++) {
416     all_cc[n_faces+i] = edges[i];
417   }
418   ierr = PetscFree(faces);CHKERRQ(ierr);
419   ierr = PetscFree(edges);CHKERRQ(ierr);
420 
421   /* map interface's subsets */
422   max_subset_size = 0;
423   for (i=0;i<n_all_cc;i++) {
424     PetscInt subset_size;
425     ierr = ISGetLocalSize(all_cc[i],&subset_size);CHKERRQ(ierr);
426     max_subset_size = PetscMax(max_subset_size,subset_size);
427   }
428   ierr = PetscMalloc1(max_subset_size,&auxmapping);CHKERRQ(ierr);
429   ierr = PetscMalloc2(graph->ncc,&auxlocal_sequential,
430                       graph->ncc,&auxlocal_parallel);CHKERRQ(ierr);
431   ierr = PetscMalloc2(graph->ncc,&index_sequential,
432                       graph->ncc,&index_parallel);CHKERRQ(ierr);
433 
434   /* if threshold is negative uses all sequential problems (possibly using MUMPS) */
435   sub_schurs->use_mumps = PETSC_FALSE;
436   if (seqthreshold < 0) {
437     seqthreshold = max_subset_size;
438 #if defined(PETSC_HAVE_MUMPS)
439     sub_schurs->use_mumps = !!A;
440 #endif
441   }
442 
443 
444   /* determine which problem has to be solved in parallel or sequentially */
445   n_local_sequential_problems = 0;
446   n_local_parallel_problems = 0;
447   for (i=0;i<n_all_cc;i++) {
448     PetscInt       subset_size,j,min_loc = 0;
449     const PetscInt *idxs;
450 
451     ierr = ISGetLocalSize(all_cc[i],&subset_size);CHKERRQ(ierr);
452     ierr = ISGetIndices(all_cc[i],&idxs);CHKERRQ(ierr);
453     ierr = ISLocalToGlobalMappingApply(graph->l2gmap,subset_size,idxs,auxmapping);CHKERRQ(ierr);
454     for (j=1;j<subset_size;j++) {
455       if (auxmapping[j]<auxmapping[min_loc]) {
456         min_loc = j;
457       }
458     }
459     if (subset_size > seqthreshold) {
460       index_parallel[n_local_parallel_problems] = i;
461       auxlocal_parallel[n_local_parallel_problems] = idxs[min_loc];
462       n_local_parallel_problems++;
463     } else {
464       index_sequential[n_local_sequential_problems] = i;
465       auxlocal_sequential[n_local_sequential_problems] = idxs[min_loc];
466       n_local_sequential_problems++;
467     }
468     ierr = ISRestoreIndices(all_cc[i],&idxs);CHKERRQ(ierr);
469   }
470 
471   /* Number parallel problems */
472   auxglobal_parallel = 0;
473   ierr = PCBDDCSubsetNumbering(PetscObjectComm((PetscObject)graph->l2gmap),graph->l2gmap,n_local_parallel_problems,auxlocal_parallel,PETSC_NULL,&n_parallel_problems,&auxglobal_parallel);CHKERRQ(ierr);
474 
475   /* Number sequential problems */
476   auxglobal_sequential = 0;
477   ierr = PCBDDCSubsetNumbering(PetscObjectComm((PetscObject)graph->l2gmap),graph->l2gmap,n_local_sequential_problems,auxlocal_sequential,PETSC_NULL,&n_sequential_problems,&auxglobal_sequential);CHKERRQ(ierr);
478 
479   /* update info in sub_schurs */
480   if (sub_schurs->use_mumps && A) {
481     ierr = PetscObjectReference((PetscObject)A);CHKERRQ(ierr);
482     sub_schurs->A = A;
483   }
484   ierr = PetscObjectReference((PetscObject)S);CHKERRQ(ierr);
485   sub_schurs->S = S;
486   ierr = PetscObjectReference((PetscObject)is_I);CHKERRQ(ierr);
487   sub_schurs->is_I = is_I;
488   ierr = PetscObjectReference((PetscObject)is_B);CHKERRQ(ierr);
489   sub_schurs->is_B = is_B;
490   ierr = PetscObjectReference((PetscObject)graph->l2gmap);CHKERRQ(ierr);
491   sub_schurs->l2gmap = graph->l2gmap;
492   ierr = PetscObjectReference((PetscObject)BtoNmap);CHKERRQ(ierr);
493   sub_schurs->BtoNmap = BtoNmap;
494   sub_schurs->n_subs_seq = n_local_sequential_problems;
495   sub_schurs->n_subs_par = n_local_parallel_problems;
496   sub_schurs->n_subs_seq_g = n_sequential_problems;
497   sub_schurs->n_subs_par_g = n_parallel_problems;
498   sub_schurs->n_subs = sub_schurs->n_subs_seq + sub_schurs->n_subs_par;
499   sub_schurs->is_subs = all_cc;
500   sub_schurs->index_sequential = index_sequential;
501   sub_schurs->index_parallel = index_parallel;
502   sub_schurs->auxglobal_sequential = auxglobal_sequential;
503   sub_schurs->auxglobal_parallel = auxglobal_parallel;
504 
505   /* free workspace */
506   ierr = PetscFree(auxmapping);CHKERRQ(ierr);
507   ierr = PetscFree2(auxlocal_sequential,auxlocal_parallel);CHKERRQ(ierr);
508 
509   PetscFunctionReturn(0);
510 }
511 
512 #undef __FUNCT__
513 #define __FUNCT__ "PCBDDCSubSchursCreate"
514 PetscErrorCode PCBDDCSubSchursCreate(PCBDDCSubSchurs *sub_schurs)
515 {
516   PCBDDCSubSchurs schurs_ctx;
517   PetscErrorCode  ierr;
518 
519   PetscFunctionBegin;
520   ierr = PetscNew(&schurs_ctx);CHKERRQ(ierr);
521   schurs_ctx->n_subs = 0;
522   *sub_schurs = schurs_ctx;
523   PetscFunctionReturn(0);
524 }
525 
526 #undef __FUNCT__
527 #define __FUNCT__ "PCBDDCSubSchursDestroy"
528 PetscErrorCode PCBDDCSubSchursDestroy(PCBDDCSubSchurs *sub_schurs)
529 {
530   PetscErrorCode ierr;
531 
532   PetscFunctionBegin;
533   ierr = PCBDDCSubSchursReset(*sub_schurs);CHKERRQ(ierr);
534   ierr = PetscFree(*sub_schurs);CHKERRQ(ierr);
535   PetscFunctionReturn(0);
536 }
537 
538 #undef __FUNCT__
539 #define __FUNCT__ "PCBDDCSubSchursReset"
540 PetscErrorCode PCBDDCSubSchursReset(PCBDDCSubSchurs sub_schurs)
541 {
542   PetscInt       i;
543   PetscErrorCode ierr;
544 
545   PetscFunctionBegin;
546   ierr = MatDestroy(&sub_schurs->A);CHKERRQ(ierr);
547   ierr = MatDestroy(&sub_schurs->S);CHKERRQ(ierr);
548   ierr = ISDestroy(&sub_schurs->is_I);CHKERRQ(ierr);
549   ierr = ISDestroy(&sub_schurs->is_B);CHKERRQ(ierr);
550   ierr = ISLocalToGlobalMappingDestroy(&sub_schurs->l2gmap);CHKERRQ(ierr);
551   ierr = ISLocalToGlobalMappingDestroy(&sub_schurs->BtoNmap);CHKERRQ(ierr);
552   ierr = MatDestroy(&sub_schurs->S_Ej_all);CHKERRQ(ierr);
553   ierr = MatDestroy(&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
554   ierr = ISDestroy(&sub_schurs->is_Ej_all);CHKERRQ(ierr);
555   for (i=0;i<sub_schurs->n_subs;i++) {
556     ierr = ISDestroy(&sub_schurs->is_subs[i]);CHKERRQ(ierr);
557     ierr = ISDestroy(&sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
558     ierr = MatDestroy(&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
559     ierr = VecDestroy(&sub_schurs->work1[i]);CHKERRQ(ierr);
560     ierr = VecDestroy(&sub_schurs->work2[i]);CHKERRQ(ierr);
561   }
562   ierr = ISDestroy(&sub_schurs->is_I_layer);CHKERRQ(ierr);
563   if (sub_schurs->n_subs) {
564     ierr = PetscFree(sub_schurs->is_subs);CHKERRQ(ierr);
565     ierr = PetscFree4(sub_schurs->is_AEj_B,sub_schurs->S_Ej,sub_schurs->work1,sub_schurs->work2);CHKERRQ(ierr);
566     ierr = PetscFree2(sub_schurs->index_sequential,sub_schurs->index_parallel);CHKERRQ(ierr);
567     ierr = PetscFree(sub_schurs->auxglobal_sequential);CHKERRQ(ierr);
568     ierr = PetscFree(sub_schurs->auxglobal_parallel);CHKERRQ(ierr);
569   }
570   sub_schurs->n_subs = 0;
571   PetscFunctionReturn(0);
572 }
573 
574 #undef __FUNCT__
575 #define __FUNCT__ "PCBDDCAdjGetNextLayer_Private"
576 PETSC_STATIC_INLINE PetscErrorCode PCBDDCAdjGetNextLayer_Private(PetscInt* queue_tip,PetscInt n_prev,PetscBT touched,PetscInt* xadj,PetscInt* adjncy,PetscInt* n_added)
577 {
578   PetscInt       i,j,n;
579   PetscErrorCode ierr;
580 
581   PetscFunctionBegin;
582   n = 0;
583   for (i=-n_prev;i<0;i++) {
584     PetscInt start_dof = queue_tip[i];
585     for (j=xadj[start_dof];j<xadj[start_dof+1];j++) {
586       PetscInt dof = adjncy[j];
587       if (!PetscBTLookup(touched,dof)) {
588         ierr = PetscBTSet(touched,dof);CHKERRQ(ierr);
589         queue_tip[n] = dof;
590         n++;
591       }
592     }
593   }
594   *n_added = n;
595   PetscFunctionReturn(0);
596 }
597 
598 #undef __FUNCT__
599 #define __FUNCT__ "PCBDDCSubSchursSetUp"
600 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)
601 {
602   Mat                    A_II,A_IB,A_BI,A_BB;
603   Mat                    AE_II,*AE_IE,*AE_EI,*AE_EE;
604   IS                     is_I,*is_subset_B;
605   ISLocalToGlobalMapping BtoNmap;
606   PetscInt               i;
607   PetscBool              is_sorted;
608   PetscErrorCode         ierr;
609 
610   PetscFunctionBegin;
611   ierr = ISSorted(is_A_I,&is_sorted);CHKERRQ(ierr);
612   if (!is_sorted) {
613     SETERRQ(PetscObjectComm((PetscObject)is_A_I),PETSC_ERR_PLIB,"IS for I dofs should be shorted");
614   }
615   ierr = ISSorted(is_A_B,&is_sorted);CHKERRQ(ierr);
616   if (!is_sorted) {
617     SETERRQ(PetscObjectComm((PetscObject)is_A_B),PETSC_ERR_PLIB,"IS for B dofs should be shorted");
618   }
619 
620   /* get Schur complement matrices */
621   ierr = MatSchurComplementGetSubMatrices(S,&A_II,NULL,&A_IB,&A_BI,&A_BB);CHKERRQ(ierr);
622 
623   /* allocate space for schur complements */
624   sub_schurs->n_subs = ncc;
625   ierr = PetscMalloc4(sub_schurs->n_subs,&sub_schurs->is_AEj_B,
626                       sub_schurs->n_subs,&sub_schurs->S_Ej,
627                       sub_schurs->n_subs,&sub_schurs->work1,
628                       sub_schurs->n_subs,&sub_schurs->work2);CHKERRQ(ierr);
629   ierr = PetscMalloc4(ncc,&is_subset_B,ncc,&AE_IE,ncc,&AE_EI,ncc,&AE_EE);CHKERRQ(ierr);
630 
631   /* maps */
632   if (sub_schurs->n_subs && nlayers >= 0 && xadj != NULL && adjncy != NULL) { /* Interior problems can be different from the original one */
633     ISLocalToGlobalMapping ItoNmap;
634     PetscBT                touched;
635     const PetscInt*        idx_B;
636     PetscInt               n_I,n_B,n_local_dofs,n_prev_added,j,layer,*local_numbering;
637 
638     /* get sizes */
639     ierr = ISGetLocalSize(is_A_I,&n_I);CHKERRQ(ierr);
640     ierr = ISGetLocalSize(is_A_B,&n_B);CHKERRQ(ierr);
641 
642     ierr = ISLocalToGlobalMappingCreateIS(is_A_I,&ItoNmap);CHKERRQ(ierr);
643     ierr = PetscMalloc1(n_I+n_B,&local_numbering);CHKERRQ(ierr);
644     ierr = PetscBTCreate(n_I+n_B,&touched);CHKERRQ(ierr);
645     ierr = PetscBTMemzero(n_I+n_B,touched);CHKERRQ(ierr);
646 
647     /* all boundary dofs must be skipped when adding layers */
648     ierr = ISGetIndices(is_A_B,&idx_B);CHKERRQ(ierr);
649     for (j=0;j<n_B;j++) {
650       ierr = PetscBTSet(touched,idx_B[j]);CHKERRQ(ierr);
651     }
652     ierr = PetscMemcpy(local_numbering,idx_B,n_B*sizeof(PetscInt));CHKERRQ(ierr);
653     ierr = ISRestoreIndices(is_A_B,&idx_B);CHKERRQ(ierr);
654 
655     /* add next layers of dofs */
656     n_local_dofs = n_B;
657     n_prev_added = n_B;
658     for (layer=0;layer<nlayers;layer++) {
659       PetscInt n_added;
660       if (n_local_dofs == n_I+n_B) break;
661       if (n_local_dofs > n_I+n_B) {
662         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);
663       }
664       ierr = PCBDDCAdjGetNextLayer_Private(local_numbering+n_local_dofs,n_prev_added,touched,xadj,adjncy,&n_added);CHKERRQ(ierr);
665       n_prev_added = n_added;
666       n_local_dofs += n_added;
667       if (!n_added) break;
668     }
669     ierr = PetscBTDestroy(&touched);CHKERRQ(ierr);
670 
671     /* IS for I dofs in original numbering and in I numbering */
672     ierr = ISCreateGeneral(PetscObjectComm((PetscObject)ItoNmap),n_local_dofs-n_B,local_numbering+n_B,PETSC_COPY_VALUES,&sub_schurs->is_I_layer);CHKERRQ(ierr);
673     ierr = PetscFree(local_numbering);CHKERRQ(ierr);
674     ierr = ISSort(sub_schurs->is_I_layer);CHKERRQ(ierr);
675     ierr = ISGlobalToLocalMappingApplyIS(ItoNmap,IS_GTOLM_DROP,sub_schurs->is_I_layer,&is_I);CHKERRQ(ierr);
676     ierr = ISLocalToGlobalMappingDestroy(&ItoNmap);CHKERRQ(ierr);
677 
678     /* II block */
679     ierr = MatGetSubMatrix(A_II,is_I,is_I,MAT_INITIAL_MATRIX,&AE_II);CHKERRQ(ierr);
680   } else {
681     PetscInt n_I;
682 
683     /* IS for I dofs in original numbering */
684     ierr = PetscObjectReference((PetscObject)is_A_I);CHKERRQ(ierr);
685     sub_schurs->is_I_layer = is_A_I;
686 
687     /* IS for I dofs in I numbering (strided 1) */
688     ierr = ISGetSize(is_A_I,&n_I);CHKERRQ(ierr);
689     ierr = ISCreateStride(PetscObjectComm((PetscObject)is_A_I),n_I,0,1,&is_I);CHKERRQ(ierr);
690 
691     /* II block is the same */
692     ierr = PetscObjectReference((PetscObject)A_II);CHKERRQ(ierr);
693     AE_II = A_II;
694   }
695 
696   /* subsets in original and boundary numbering */
697   ierr = ISLocalToGlobalMappingCreateIS(is_A_B,&BtoNmap);CHKERRQ(ierr);
698   for (i=0;i<sub_schurs->n_subs;i++) {
699     ierr = ISDuplicate(is_cc[i],&sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
700     ierr = ISSort(sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
701     ierr = ISGlobalToLocalMappingApplyIS(BtoNmap,IS_GTOLM_DROP,sub_schurs->is_AEj_B[i],&is_subset_B[i]);CHKERRQ(ierr);
702   }
703   ierr = ISLocalToGlobalMappingDestroy(&BtoNmap);CHKERRQ(ierr);
704 
705   /* EE block */
706   for (i=0;i<sub_schurs->n_subs;i++) {
707     ierr = MatGetSubMatrix(A_BB,is_subset_B[i],is_subset_B[i],MAT_INITIAL_MATRIX,&AE_EE[i]);CHKERRQ(ierr);
708   }
709   /* IE block */
710   for (i=0;i<sub_schurs->n_subs;i++) {
711     ierr = MatGetSubMatrix(A_IB,is_I,is_subset_B[i],MAT_INITIAL_MATRIX,&AE_IE[i]);CHKERRQ(ierr);
712   }
713   /* EI block */
714   for (i=0;i<sub_schurs->n_subs;i++) {
715     ierr = MatGetSubMatrix(A_BI,is_subset_B[i],is_I,MAT_INITIAL_MATRIX,&AE_EI[i]);CHKERRQ(ierr);
716   }
717 
718   /* setup Schur complements on subset */
719   for (i=0;i<sub_schurs->n_subs;i++) {
720     ierr = MatCreateSchurComplement(AE_II,AE_II,AE_IE[i],AE_EI[i],AE_EE[i],&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
721     ierr = MatCreateVecs(sub_schurs->S_Ej[i],&sub_schurs->work1[i],&sub_schurs->work2[i]);CHKERRQ(ierr);
722     if (AE_II == A_II) { /* we can reuse the same ksp */
723       KSP ksp;
724       ierr = MatSchurComplementGetKSP(S,&ksp);CHKERRQ(ierr);
725       ierr = MatSchurComplementSetKSP(sub_schurs->S_Ej[i],ksp);CHKERRQ(ierr);
726     } else { /* build new ksp object which inherits ksp and pc types from the original one */
727       KSP      origksp,schurksp;
728       PC       origpc,schurpc;
729       KSPType  ksp_type;
730       PCType   pc_type;
731       PetscInt n_internal;
732 
733       ierr = MatSchurComplementGetKSP(S,&origksp);CHKERRQ(ierr);
734       ierr = MatSchurComplementGetKSP(sub_schurs->S_Ej[i],&schurksp);CHKERRQ(ierr);
735       ierr = KSPGetType(origksp,&ksp_type);CHKERRQ(ierr);
736       ierr = KSPSetType(schurksp,ksp_type);CHKERRQ(ierr);
737       ierr = KSPGetPC(schurksp,&schurpc);CHKERRQ(ierr);
738       ierr = KSPGetPC(origksp,&origpc);CHKERRQ(ierr);
739       ierr = PCGetType(origpc,&pc_type);CHKERRQ(ierr);
740       ierr = PCSetType(schurpc,pc_type);CHKERRQ(ierr);
741       ierr = ISGetSize(is_I,&n_internal);CHKERRQ(ierr);
742       if (n_internal) { /* UMFPACK gives error with 0 sized problems */
743         MatSolverPackage solver=NULL;
744         ierr = PCFactorGetMatSolverPackage(origpc,(const MatSolverPackage*)&solver);CHKERRQ(ierr);
745         if (solver) {
746           ierr = PCFactorSetMatSolverPackage(schurpc,solver);CHKERRQ(ierr);
747         }
748       }
749       ierr = KSPSetUp(schurksp);CHKERRQ(ierr);
750     }
751   }
752   /* free */
753   ierr = ISDestroy(&is_I);CHKERRQ(ierr);
754   ierr = MatDestroy(&AE_II);CHKERRQ(ierr);
755   for (i=0;i<sub_schurs->n_subs;i++) {
756     ierr = MatDestroy(&AE_EE[i]);CHKERRQ(ierr);
757     ierr = MatDestroy(&AE_IE[i]);CHKERRQ(ierr);
758     ierr = MatDestroy(&AE_EI[i]);CHKERRQ(ierr);
759     ierr = ISDestroy(&is_subset_B[i]);CHKERRQ(ierr);
760   }
761   ierr = PetscFree4(is_subset_B,AE_IE,AE_EI,AE_EE);CHKERRQ(ierr);
762   PetscFunctionReturn(0);
763 }
764