xref: /petsc/src/ksp/pc/impls/bddc/bddcschurs.c (revision a58a30b4bf9d00545e20033ff3f2527e68041eaf)
1 #include <../src/ksp/pc/impls/bddc/bddc.h>
2 #include <../src/ksp/pc/impls/bddc/bddcprivate.h>
3 #include <petscblaslapack.h>
4 
5 PETSC_STATIC_INLINE PetscErrorCode PCBDDCAdjGetNextLayer_Private(PetscInt*,PetscInt,PetscBT,PetscInt*,PetscInt*,PetscInt*);
6 static PetscErrorCode PCBDDCComputeExplicitSchur(Mat M, Mat *S);
7 
8 #undef __FUNCT__
9 #define __FUNCT__ "PCBDDCComputeExplicitSchur"
10 static PetscErrorCode PCBDDCComputeExplicitSchur(Mat M, Mat *S)
11 {
12   Mat            B, C, D, Bd, Cd, AinvBd;
13   KSP            ksp;
14   PC             pc;
15   PetscBool      isLU, isILU, isCHOL, Bdense, Cdense;
16   PetscReal      fill = 2.0;
17   PetscMPIInt    size;
18   PetscErrorCode ierr;
19 
20   PetscFunctionBegin;
21   ierr = MPI_Comm_size(PetscObjectComm((PetscObject)M),&size);CHKERRQ(ierr);
22   if (size != 1) {
23     SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Not for parallel matrices");
24   }
25   ierr = MatSchurComplementGetSubMatrices(M, NULL, NULL, &B, &C, &D);CHKERRQ(ierr);
26   ierr = MatSchurComplementGetKSP(M, &ksp);CHKERRQ(ierr);
27   ierr = KSPGetPC(ksp, &pc);CHKERRQ(ierr);
28   ierr = PetscObjectTypeCompare((PetscObject) pc, PCLU, &isLU);CHKERRQ(ierr);
29   ierr = PetscObjectTypeCompare((PetscObject) pc, PCILU, &isILU);CHKERRQ(ierr);
30   ierr = PetscObjectTypeCompare((PetscObject) pc, PCCHOLESKY, &isCHOL);CHKERRQ(ierr);
31   ierr = PetscObjectTypeCompare((PetscObject) B, MATSEQDENSE, &Bdense);CHKERRQ(ierr);
32   ierr = PetscObjectTypeCompare((PetscObject) C, MATSEQDENSE, &Cdense);CHKERRQ(ierr);
33   if (!Bdense) {
34     ierr = MatConvert(B, MATSEQDENSE, MAT_INITIAL_MATRIX, &Bd);CHKERRQ(ierr);
35   } else {
36     Bd = B;
37   }
38 
39   if (isLU || isILU || isCHOL) {
40     Mat fact;
41 
42     ierr = KSPSetUp(ksp);CHKERRQ(ierr);
43     ierr = PCFactorGetMatrix(pc, &fact);CHKERRQ(ierr);
44     ierr = MatDuplicate(Bd, MAT_DO_NOT_COPY_VALUES, &AinvBd);CHKERRQ(ierr);
45     ierr = MatMatSolve(fact, Bd, AinvBd);CHKERRQ(ierr);
46   } else {
47     Mat Ainvd;
48 
49     ierr = PCComputeExplicitOperator(pc, &Ainvd);CHKERRQ(ierr);
50     ierr = MatMatMult(Ainvd, Bd, MAT_INITIAL_MATRIX, fill, &AinvBd);CHKERRQ(ierr);
51     ierr = MatDestroy(&Ainvd);CHKERRQ(ierr);
52   }
53   if (!Bdense) {
54     ierr = MatDestroy(&Bd);CHKERRQ(ierr);
55   }
56   if (!Cdense) {
57     ierr = MatConvert(C, MATSEQDENSE, MAT_INITIAL_MATRIX, &Cd);CHKERRQ(ierr);
58   } else {
59     Cd = C;
60   }
61 
62   ierr = MatMatMult(Cd, AinvBd, MAT_INITIAL_MATRIX, fill, S);CHKERRQ(ierr);
63   ierr = MatDestroy(&AinvBd);CHKERRQ(ierr);
64   if (!Cdense) {
65     ierr = MatDestroy(&Cd);CHKERRQ(ierr);
66   }
67 
68   if (D) {
69     Mat       Dd;
70     PetscBool Ddense;
71 
72     ierr = PetscObjectTypeCompare((PetscObject)D,MATSEQDENSE,&Ddense);CHKERRQ(ierr);
73     if (!Ddense) {
74       ierr = MatConvert(D, MATSEQDENSE, MAT_INITIAL_MATRIX, &Dd);CHKERRQ(ierr);
75     } else {
76       Dd = D;
77     }
78     ierr = MatAYPX(*S,-1.0,Dd,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
79     if (!Ddense) {
80       ierr = MatDestroy(&Dd);CHKERRQ(ierr);
81     }
82   } else {
83     ierr = MatScale(*S,-1.0);CHKERRQ(ierr);
84   }
85   PetscFunctionReturn(0);
86 }
87 
88 #undef __FUNCT__
89 #define __FUNCT__ "PCBDDCSubSchursSetUp"
90 PetscErrorCode PCBDDCSubSchursSetUp(PCBDDCSubSchurs sub_schurs, PetscInt xadj[], PetscInt adjncy[], PetscInt nlayers, PetscBool compute_Stilda, PetscBool deluxe, PetscBool use_edges, PetscBool use_faces)
91 {
92   Mat                    A_II,A_IB,A_BI,A_BB;
93   Mat                    AE_II,*AE_IE,*AE_EI,*AE_EE;
94   Mat                    S_all,global_schur_subsets,work_mat;
95   Mat                    S_Ej_tilda_all,S_Ej_inv_all;
96   ISLocalToGlobalMapping l2gmap_subsets;
97   IS                     is_I,*is_subset_B,temp_is;
98   PetscInt               *nnz,*all_local_idx_G,*all_local_idx_B,*all_local_idx_N;
99   PetscInt               i,subset_size,max_subset_size;
100   PetscInt               extra,local_size,global_size;
101   PetscBool              is_symmetric,Stilda_computed;
102   PetscBLASInt           B_N,B_ierr,B_lwork,*pivots;
103   PetscScalar            *work;
104   PetscErrorCode         ierr;
105 
106   PetscFunctionBegin;
107   /* get Schur complement matrices */
108   if (!sub_schurs->use_mumps) {
109     if (compute_Stilda) {
110       SETERRQ(PetscObjectComm((PetscObject)sub_schurs->l2gmap),PETSC_ERR_SUP,"Computation of Stildas requires MUMPS");
111     }
112     ierr = MatSchurComplementGetSubMatrices(sub_schurs->S,&A_II,NULL,&A_IB,&A_BI,&A_BB);CHKERRQ(ierr);
113     ierr = PetscMalloc4(sub_schurs->n_subs,&is_subset_B,
114                         sub_schurs->n_subs,&AE_IE,
115                         sub_schurs->n_subs,&AE_EI,
116                         sub_schurs->n_subs,&AE_EE);CHKERRQ(ierr);
117   } else {
118     is_subset_B = NULL;
119     AE_IE = NULL;
120     AE_EI = NULL;
121     AE_EE = NULL;
122   }
123 
124   /* determine interior problems */
125   ierr = ISDestroy(&sub_schurs->is_I_layer);CHKERRQ(ierr);
126   if (nlayers >= 0 && xadj != NULL && adjncy != NULL) { /* Interior problems can be different from the original one */
127     PetscBT                touched;
128     const PetscInt*        idx_B;
129     PetscInt               n_I,n_B,n_local_dofs,n_prev_added,j,layer,*local_numbering;
130 
131     /* get sizes */
132     ierr = ISGetLocalSize(sub_schurs->is_I,&n_I);CHKERRQ(ierr);
133     ierr = ISGetLocalSize(sub_schurs->is_B,&n_B);CHKERRQ(ierr);
134 
135     ierr = PetscMalloc1(n_I+n_B,&local_numbering);CHKERRQ(ierr);
136     ierr = PetscBTCreate(n_I+n_B,&touched);CHKERRQ(ierr);
137     ierr = PetscBTMemzero(n_I+n_B,touched);CHKERRQ(ierr);
138 
139     /* all boundary dofs must be skipped when adding layers */
140     ierr = ISGetIndices(sub_schurs->is_B,&idx_B);CHKERRQ(ierr);
141     for (j=0;j<n_B;j++) {
142       ierr = PetscBTSet(touched,idx_B[j]);CHKERRQ(ierr);
143     }
144     ierr = PetscMemcpy(local_numbering,idx_B,n_B*sizeof(PetscInt));CHKERRQ(ierr);
145     ierr = ISRestoreIndices(sub_schurs->is_B,&idx_B);CHKERRQ(ierr);
146 
147     /* add prescribed number of layers of dofs */
148     n_local_dofs = n_B;
149     n_prev_added = n_B;
150     for (layer=0;layer<nlayers;layer++) {
151       PetscInt n_added;
152       if (n_local_dofs == n_I+n_B) break;
153       if (n_local_dofs > n_I+n_B) {
154         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);
155       }
156       ierr = PCBDDCAdjGetNextLayer_Private(local_numbering+n_local_dofs,n_prev_added,touched,xadj,adjncy,&n_added);CHKERRQ(ierr);
157       n_prev_added = n_added;
158       n_local_dofs += n_added;
159       if (!n_added) break;
160     }
161     ierr = PetscBTDestroy(&touched);CHKERRQ(ierr);
162 
163     /* IS for I layer dofs in original numbering */
164     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);
165     ierr = PetscFree(local_numbering);CHKERRQ(ierr);
166     ierr = ISSort(sub_schurs->is_I_layer);CHKERRQ(ierr);
167     /* IS for I layer dofs in I numbering */
168     if (!sub_schurs->use_mumps) {
169       ISLocalToGlobalMapping ItoNmap;
170       ierr = ISLocalToGlobalMappingCreateIS(sub_schurs->is_I,&ItoNmap);CHKERRQ(ierr);
171       ierr = ISGlobalToLocalMappingApplyIS(ItoNmap,IS_GTOLM_DROP,sub_schurs->is_I_layer,&is_I);CHKERRQ(ierr);
172       ierr = ISLocalToGlobalMappingDestroy(&ItoNmap);CHKERRQ(ierr);
173 
174       /* II block */
175       ierr = MatGetSubMatrix(A_II,is_I,is_I,MAT_INITIAL_MATRIX,&AE_II);CHKERRQ(ierr);
176     }
177   } else {
178     PetscInt n_I;
179 
180     /* IS for I dofs in original numbering */
181     ierr = PetscObjectReference((PetscObject)sub_schurs->is_I);CHKERRQ(ierr);
182     sub_schurs->is_I_layer = sub_schurs->is_I;
183 
184     /* IS for I dofs in I numbering (strided 1) */
185     if (!sub_schurs->use_mumps) {
186       ierr = ISGetSize(sub_schurs->is_I,&n_I);CHKERRQ(ierr);
187       ierr = ISCreateStride(PetscObjectComm((PetscObject)sub_schurs->is_I),n_I,0,1,&is_I);CHKERRQ(ierr);
188 
189       /* II block is the same */
190       ierr = PetscObjectReference((PetscObject)A_II);CHKERRQ(ierr);
191       AE_II = A_II;
192     }
193   }
194 
195   /* Get info on subset sizes and sum of all subsets sizes */
196   max_subset_size = 0;
197   local_size = 0;
198   for (i=0;i<sub_schurs->n_subs_seq;i++) {
199     PetscInt j = sub_schurs->index_sequential[i];
200     ierr = ISGetLocalSize(sub_schurs->is_subs[j],&subset_size);CHKERRQ(ierr);
201     max_subset_size = PetscMax(subset_size,max_subset_size);
202     local_size += subset_size;
203   }
204 
205   /* Work arrays for local indices */
206   ierr = PetscMalloc1(local_size,&all_local_idx_B);CHKERRQ(ierr);
207   extra = 0;
208   if (sub_schurs->use_mumps) {
209     ierr = ISGetLocalSize(sub_schurs->is_I_layer,&extra);CHKERRQ(ierr);
210   }
211   ierr = PetscMalloc1(local_size+extra,&all_local_idx_N);CHKERRQ(ierr);
212   if (extra) {
213     const PetscInt *idxs;
214     ierr = ISGetIndices(sub_schurs->is_I_layer,&idxs);CHKERRQ(ierr);
215     ierr = PetscMemcpy(all_local_idx_N,idxs,extra*sizeof(PetscInt));CHKERRQ(ierr);
216     ierr = ISRestoreIndices(sub_schurs->is_I_layer,&idxs);CHKERRQ(ierr);
217   }
218   ierr = PetscMalloc1(local_size,&nnz);CHKERRQ(ierr);
219 
220   /* Get local indices in local numbering */
221   local_size = 0;
222   for (i=0;i<sub_schurs->n_subs_seq;i++) {
223     PetscInt j;
224     const    PetscInt *idxs;
225 
226     PetscInt local_problem_index = sub_schurs->index_sequential[i];
227     ierr = ISGetLocalSize(sub_schurs->is_subs[local_problem_index],&subset_size);CHKERRQ(ierr);
228     ierr = ISGetIndices(sub_schurs->is_subs[local_problem_index],&idxs);CHKERRQ(ierr);
229     /* subset indices in local numbering */
230     ierr = PetscMemcpy(all_local_idx_N+local_size+extra,idxs,subset_size*sizeof(PetscInt));CHKERRQ(ierr);
231     ierr = ISRestoreIndices(sub_schurs->is_subs[local_problem_index],&idxs);CHKERRQ(ierr);
232     for (j=0;j<subset_size;j++) nnz[local_size+j] = subset_size;
233     local_size += subset_size;
234   }
235 
236   S_all = NULL;
237   ierr = MatIsSymmetric(sub_schurs->A,0.0,&is_symmetric);CHKERRQ(ierr);
238   if (!sub_schurs->use_mumps) {
239     /* subsets in original and boundary numbering */
240     for (i=0;i<sub_schurs->n_subs;i++) {
241       ierr = ISGlobalToLocalMappingApplyIS(sub_schurs->BtoNmap,IS_GTOLM_DROP,sub_schurs->is_subs[i],&is_subset_B[i]);CHKERRQ(ierr);
242     }
243 
244     /* EE block */
245     for (i=0;i<sub_schurs->n_subs;i++) {
246       ierr = MatGetSubMatrix(A_BB,is_subset_B[i],is_subset_B[i],MAT_INITIAL_MATRIX,&AE_EE[i]);CHKERRQ(ierr);
247     }
248     /* IE block */
249     for (i=0;i<sub_schurs->n_subs;i++) {
250       ierr = MatGetSubMatrix(A_IB,is_I,is_subset_B[i],MAT_INITIAL_MATRIX,&AE_IE[i]);CHKERRQ(ierr);
251     }
252     /* EI block */
253     for (i=0;i<sub_schurs->n_subs;i++) {
254       ierr = MatGetSubMatrix(A_BI,is_subset_B[i],is_I,MAT_INITIAL_MATRIX,&AE_EI[i]);CHKERRQ(ierr);
255     }
256 
257     /* setup Schur complements on subset */
258     for (i=0;i<sub_schurs->n_subs;i++) {
259       ierr = MatDestroy(&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
260       ierr = MatCreateSchurComplement(AE_II,AE_II,AE_IE[i],AE_EI[i],AE_EE[i],&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
261       ierr = MatDestroy(&AE_EE[i]);CHKERRQ(ierr);
262       ierr = MatDestroy(&AE_IE[i]);CHKERRQ(ierr);
263       ierr = MatDestroy(&AE_EI[i]);CHKERRQ(ierr);
264       if (AE_II == A_II) { /* we can reuse the same ksp */
265         KSP ksp;
266         ierr = MatSchurComplementGetKSP(sub_schurs->S,&ksp);CHKERRQ(ierr);
267         ierr = MatSchurComplementSetKSP(sub_schurs->S_Ej[i],ksp);CHKERRQ(ierr);
268       } else { /* build new ksp object which inherits ksp and pc types from the original one */
269         KSP      origksp,schurksp;
270         PC       origpc,schurpc;
271         KSPType  ksp_type;
272         PCType   pc_type;
273         PetscInt n_internal;
274 
275         ierr = MatSchurComplementGetKSP(sub_schurs->S,&origksp);CHKERRQ(ierr);
276         ierr = MatSchurComplementGetKSP(sub_schurs->S_Ej[i],&schurksp);CHKERRQ(ierr);
277         ierr = KSPGetType(origksp,&ksp_type);CHKERRQ(ierr);
278         ierr = KSPSetType(schurksp,ksp_type);CHKERRQ(ierr);
279         ierr = KSPGetPC(schurksp,&schurpc);CHKERRQ(ierr);
280         ierr = KSPGetPC(origksp,&origpc);CHKERRQ(ierr);
281         ierr = PCGetType(origpc,&pc_type);CHKERRQ(ierr);
282         ierr = PCSetType(schurpc,pc_type);CHKERRQ(ierr);
283         ierr = ISGetSize(is_I,&n_internal);CHKERRQ(ierr);
284         if (n_internal) { /* UMFPACK gives error with 0 sized problems */
285           MatSolverPackage solver=NULL;
286           ierr = PCFactorGetMatSolverPackage(origpc,(const MatSolverPackage*)&solver);CHKERRQ(ierr);
287           if (solver) {
288             ierr = PCFactorSetMatSolverPackage(schurpc,solver);CHKERRQ(ierr);
289           }
290         }
291         ierr = KSPSetUp(schurksp);CHKERRQ(ierr);
292       }
293     }
294     /* free */
295     ierr = ISDestroy(&is_I);CHKERRQ(ierr);
296     ierr = MatDestroy(&AE_II);CHKERRQ(ierr);
297     for (i=0;i<sub_schurs->n_subs;i++) {
298       ierr = ISDestroy(&is_subset_B[i]);CHKERRQ(ierr);
299     }
300     ierr = PetscFree4(is_subset_B,AE_IE,AE_EI,AE_EE);CHKERRQ(ierr);
301 #if defined(PETSC_HAVE_MUMPS)
302   } else {
303     Mat           A,F;
304     IS            is_A_all;
305     PetscInt      *idxs_schur,n_I;
306 
307     /* get working mat */
308     ierr = ISGetLocalSize(sub_schurs->is_I_layer,&n_I);CHKERRQ(ierr);
309     ierr = ISCreateGeneral(PETSC_COMM_SELF,local_size+n_I,all_local_idx_N,PETSC_COPY_VALUES,&is_A_all);CHKERRQ(ierr);
310     ierr = MatGetSubMatrixUnsorted(sub_schurs->A,is_A_all,is_A_all,MAT_INITIAL_MATRIX,&A);CHKERRQ(ierr);
311     ierr = ISDestroy(&is_A_all);CHKERRQ(ierr);
312 
313     if (n_I) {
314       if (is_symmetric) {
315         ierr = MatGetFactor(A,MATSOLVERMUMPS,MAT_FACTOR_CHOLESKY,&F);CHKERRQ(ierr);
316       } else {
317         ierr = MatGetFactor(A,MATSOLVERMUMPS,MAT_FACTOR_LU,&F);CHKERRQ(ierr);
318       }
319 
320       /* subsets ordered last */
321       ierr = PetscMalloc1(local_size,&idxs_schur);CHKERRQ(ierr);
322       for (i=0;i<local_size;i++) {
323         idxs_schur[i] = n_I+i+1;
324       }
325       ierr = MatMumpsSetSchurIndices(F,local_size,idxs_schur);CHKERRQ(ierr);
326       ierr = PetscFree(idxs_schur);CHKERRQ(ierr);
327 
328       /* factorization step */
329       if (is_symmetric) {
330         ierr = MatCholeskyFactorSymbolic(F,A,NULL,NULL);CHKERRQ(ierr);
331         ierr = MatCholeskyFactorNumeric(F,A,NULL);CHKERRQ(ierr);
332       } else {
333         ierr = MatLUFactorSymbolic(F,A,NULL,NULL,NULL);CHKERRQ(ierr);
334         ierr = MatLUFactorNumeric(F,A,NULL);CHKERRQ(ierr);
335       }
336 
337       /* get explicit Schur Complement computed during numeric factorization */
338       ierr = MatMumpsGetSchurComplement(F,&S_all);CHKERRQ(ierr);
339       ierr = MatDestroy(&F);CHKERRQ(ierr);
340     } else {
341       ierr = MatConvert(A,MATSEQDENSE,MAT_INITIAL_MATRIX,&S_all);CHKERRQ(ierr);
342     }
343     ierr = MatDestroy(&A);CHKERRQ(ierr);
344 #endif
345   }
346 
347   if (!sub_schurs->n_subs_seq_g) {
348     PetscFunctionReturn(0);
349   }
350 
351   /* subset indices in local boundary numbering */
352   if (!sub_schurs->is_Ej_all) {
353     ierr = ISGlobalToLocalMappingApply(sub_schurs->BtoNmap,IS_GTOLM_DROP,local_size,all_local_idx_N+extra,&subset_size,all_local_idx_B);CHKERRQ(ierr);
354     if (subset_size != local_size) {
355       SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Error in sub_schurs serial (BtoNmap)! %d != %d\n",subset_size,local_size);
356     }
357     ierr = ISCreateGeneral(PETSC_COMM_SELF,local_size,all_local_idx_B,PETSC_OWN_POINTER,&sub_schurs->is_Ej_all);CHKERRQ(ierr);
358   }
359 
360   /* Local matrix of all local Schur on subsets transposed */
361   if (!sub_schurs->S_Ej_all) {
362     ierr = MatCreate(PETSC_COMM_SELF,&sub_schurs->S_Ej_all);CHKERRQ(ierr);
363     ierr = MatSetSizes(sub_schurs->S_Ej_all,PETSC_DECIDE,PETSC_DECIDE,local_size,local_size);CHKERRQ(ierr);
364     ierr = MatSetType(sub_schurs->S_Ej_all,MATAIJ);CHKERRQ(ierr);
365     ierr = MatSeqAIJSetPreallocation(sub_schurs->S_Ej_all,0,nnz);CHKERRQ(ierr);
366   } else {
367     ierr = MatZeroEntries(sub_schurs->S_Ej_all);CHKERRQ(ierr);
368   }
369 
370   S_Ej_tilda_all = 0;
371   S_Ej_inv_all = 0;
372   work = NULL;
373   pivots = NULL;
374   Stilda_computed = PETSC_FALSE;
375   if (sub_schurs->n_subs && deluxe) { /* workspace needed only for GETRI */
376     PetscScalar lwork;
377 
378     B_lwork = -1;
379     ierr = PetscBLASIntCast(max_subset_size,&B_N);CHKERRQ(ierr);
380     ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
381     PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,work,&B_N,pivots,&lwork,&B_lwork,&B_ierr));
382     ierr = PetscFPTrapPop();CHKERRQ(ierr);
383     if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in query to GETRI Lapack routine %d",(int)B_ierr);
384     ierr = PetscBLASIntCast((PetscInt)lwork,&B_lwork);CHKERRQ(ierr);
385     ierr = PetscMalloc2(B_lwork,&work,max_subset_size,&pivots);CHKERRQ(ierr);
386   }
387 
388   ierr = PetscBTMemzero(sub_schurs->n_subs,sub_schurs->computed_Stilda_subs);CHKERRQ(ierr);
389   if (!sub_schurs->use_mumps) {
390     PetscScalar *fill_vals;
391     PetscInt    *dummy_idx;
392 
393     /* Work arrays */
394     ierr = PetscMalloc1(max_subset_size,&dummy_idx);CHKERRQ(ierr);
395     /* Loop on local problems end compute Schur complements explicitly */
396     local_size = 0;
397     for (i=0;i<sub_schurs->n_subs_seq;i++) {
398       Mat       S_Ej_expl;
399       PetscInt  j,lpi = sub_schurs->index_sequential[i];
400       PetscBool Sdense;
401 
402       ierr = PCBDDCComputeExplicitSchur(sub_schurs->S_Ej[lpi],&S_Ej_expl);CHKERRQ(ierr);
403       ierr = ISGetLocalSize(sub_schurs->is_subs[lpi],&subset_size);CHKERRQ(ierr);
404       ierr = PetscObjectTypeCompare((PetscObject)S_Ej_expl,MATSEQDENSE,&Sdense);CHKERRQ(ierr);
405       if (Sdense) {
406         for (j=0;j<subset_size;j++) {
407           dummy_idx[j]=local_size+j;
408         }
409         ierr = MatDenseGetArray(S_Ej_expl,&fill_vals);CHKERRQ(ierr);
410         ierr = MatSetValues(sub_schurs->S_Ej_all,subset_size,dummy_idx,subset_size,dummy_idx,fill_vals,INSERT_VALUES);CHKERRQ(ierr);
411         ierr = MatDenseRestoreArray(S_Ej_expl,&fill_vals);CHKERRQ(ierr);
412       } else {
413         SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Not yet implemented for sparse matrices");
414       }
415       local_size += subset_size;
416       ierr = MatDestroy(&sub_schurs->S_Ej[lpi]);CHKERRQ(ierr);
417       sub_schurs->S_Ej[lpi] = S_Ej_expl;
418     }
419     /* Stildas are not computed without mumps */
420     for (i=0;i<sub_schurs->n_subs;i++) {
421       ierr = MatDestroy(&sub_schurs->S_Ej_tilda[i]);CHKERRQ(ierr);
422     }
423     ierr = PetscFree(dummy_idx);CHKERRQ(ierr);
424   } else {
425     PetscInt  *dummy_idx,n_all;
426 
427     if (compute_Stilda) {
428       ierr = MatCreate(PETSC_COMM_SELF,&S_Ej_tilda_all);CHKERRQ(ierr);
429       ierr = MatSetSizes(S_Ej_tilda_all,PETSC_DECIDE,PETSC_DECIDE,local_size,local_size);CHKERRQ(ierr);
430       ierr = MatSetType(S_Ej_tilda_all,MATAIJ);CHKERRQ(ierr);
431       ierr = MatSeqAIJSetPreallocation(S_Ej_tilda_all,0,nnz);CHKERRQ(ierr);
432       if (deluxe) {
433         ierr = MatCreate(PETSC_COMM_SELF,&S_Ej_inv_all);CHKERRQ(ierr);
434         ierr = MatSetSizes(S_Ej_inv_all,PETSC_DECIDE,PETSC_DECIDE,local_size,local_size);CHKERRQ(ierr);
435         ierr = MatSetType(S_Ej_inv_all,MATAIJ);CHKERRQ(ierr);
436         ierr = MatSeqAIJSetPreallocation(S_Ej_inv_all,0,nnz);CHKERRQ(ierr);
437       }
438     }
439 
440     ierr = MatGetSize(S_all,&n_all,NULL);CHKERRQ(ierr);
441     local_size = 0;
442     /* Work arrays */
443     ierr = PetscMalloc1(max_subset_size,&dummy_idx);CHKERRQ(ierr);
444 
445     Stilda_computed = PETSC_FALSE;
446     for (i=0;i<sub_schurs->n_subs;i++) {
447       IS  is_E;
448       PetscScalar *vals;
449       PetscInt j;
450 
451       ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
452       for (j=0;j<subset_size;j++) {
453         dummy_idx[j]=local_size+j;
454       }
455       ierr = ISCreateStride(PetscObjectComm((PetscObject)sub_schurs->is_I),subset_size,local_size,1,&is_E);CHKERRQ(ierr);
456       if (sub_schurs->S_Ej[i]) {
457         ierr = MatGetSubMatrix(S_all,is_E,is_E,MAT_REUSE_MATRIX,&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
458       } else {
459         ierr = MatGetSubMatrix(S_all,is_E,is_E,MAT_INITIAL_MATRIX,&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
460       }
461       ierr = MatDenseGetArray(sub_schurs->S_Ej[i],&vals);CHKERRQ(ierr);
462       ierr = MatSetValues(sub_schurs->S_Ej_all,subset_size,dummy_idx,subset_size,dummy_idx,vals,INSERT_VALUES);CHKERRQ(ierr);
463       ierr = MatDenseRestoreArray(sub_schurs->S_Ej[i],&vals);CHKERRQ(ierr);
464 
465       if (compute_Stilda && ((PetscBTLookup(sub_schurs->is_edge,i) && use_edges) || use_faces)) {
466         ierr = PetscBTSet(sub_schurs->computed_Stilda_subs,i);CHKERRQ(ierr);
467         Stilda_computed = PETSC_TRUE;
468       }
469 
470       if (PetscBTLookup(sub_schurs->computed_Stilda_subs,i)) {
471         Mat Stilda;
472         if (sub_schurs->n_subs == 1) {
473           ierr = PetscObjectReference((PetscObject)sub_schurs->S_Ej[i]);CHKERRQ(ierr);
474           Stilda = sub_schurs->S_Ej[i];
475         } else {
476           KSP ksp;
477           PC  pc;
478           Mat S_EF,S_FE,S_FF,Stilda_impl;
479           IS  is_F;
480           PetscScalar eps=1.e-8;
481           PetscBool chop=PETSC_FALSE;
482 
483           ierr = ISComplement(is_E,0,n_all,&is_F);CHKERRQ(ierr);
484           ierr = MatGetSubMatrix(S_all,is_E,is_F,MAT_INITIAL_MATRIX,&S_EF);CHKERRQ(ierr);
485           ierr = MatGetSubMatrix(S_all,is_F,is_F,MAT_INITIAL_MATRIX,&S_FF);CHKERRQ(ierr);
486           ierr = MatGetSubMatrix(S_all,is_F,is_E,MAT_INITIAL_MATRIX,&S_FE);CHKERRQ(ierr);
487           ierr = ISDestroy(&is_F);CHKERRQ(ierr);
488           if (chop) {
489             ierr = MatChop(S_FF,eps);CHKERRQ(ierr);
490             ierr = MatConvert(S_FF,MATAIJ,MAT_REUSE_MATRIX,&S_FF);CHKERRQ(ierr);
491           }
492           ierr = MatCreateSchurComplement(S_FF,S_FF,S_FE,S_EF,sub_schurs->S_Ej[i],&Stilda_impl);CHKERRQ(ierr);
493           ierr = MatDestroy(&S_FF);CHKERRQ(ierr);
494           ierr = MatDestroy(&S_FE);CHKERRQ(ierr);
495           ierr = MatDestroy(&S_EF);CHKERRQ(ierr);
496           ierr = MatSchurComplementGetKSP(Stilda_impl,&ksp);CHKERRQ(ierr);
497           ierr = KSPSetType(ksp,KSPPREONLY);CHKERRQ(ierr);
498           ierr = KSPGetPC(ksp,&pc);CHKERRQ(ierr);
499           if (is_symmetric) {
500             ierr = PCSetType(pc,PCCHOLESKY);CHKERRQ(ierr);
501           } else {
502             ierr = PCSetType(pc,PCLU);CHKERRQ(ierr);
503           }
504           if (!chop) {
505             ierr = PCFactorSetUseInPlace(pc,PETSC_TRUE);CHKERRQ(ierr);
506           } else {
507             ierr = PCFactorSetMatSolverPackage(pc,MATSOLVERMUMPS);CHKERRQ(ierr);
508           }
509           ierr = KSPSetUp(ksp);CHKERRQ(ierr);
510           ierr = PCBDDCComputeExplicitSchur(Stilda_impl,&Stilda);CHKERRQ(ierr);
511           ierr = MatDestroy(&Stilda_impl);CHKERRQ(ierr);
512         }
513 /*
514         PetscViewerPushFormat(PETSC_VIEWER_STDOUT_SELF,PETSC_VIEWER_ASCII_MATLAB);
515         ierr = MatView(Stilda,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
516         PetscViewerPopFormat(PETSC_VIEWER_STDOUT_SELF);
517 */
518         ierr = MatDestroy(&sub_schurs->S_Ej_tilda[i]);CHKERRQ(ierr);
519         sub_schurs->S_Ej_tilda[i] = Stilda;
520 
521 
522         ierr = MatDenseGetArray(sub_schurs->S_Ej_tilda[i],&vals);CHKERRQ(ierr);
523         if (deluxe) { /* when using deluxe scaling, we need (S_1^-1+S_2^-1)^-1 */
524           PetscScalar *vals2;
525 
526           ierr = MatDenseGetArray(sub_schurs->S_Ej[i],&vals2);CHKERRQ(ierr);
527           /* need to be optimized (cholesky) */
528           ierr = PetscBLASIntCast(subset_size,&B_N);CHKERRQ(ierr);
529           ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
530           PetscStackCallBLAS("LAPACKgetrf",LAPACKgetrf_(&B_N,&B_N,vals,&B_N,pivots,&B_ierr));
531           if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRF Lapack routine %d",(int)B_ierr);
532           PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,vals,&B_N,pivots,work,&B_lwork,&B_ierr));
533           if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRI Lapack routine %d",(int)B_ierr);
534           PetscStackCallBLAS("LAPACKgetrf",LAPACKgetrf_(&B_N,&B_N,vals2,&B_N,pivots,&B_ierr));
535           if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRF Lapack routine %d",(int)B_ierr);
536           PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,vals2,&B_N,pivots,work,&B_lwork,&B_ierr));
537           if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRI Lapack routine %d",(int)B_ierr);
538           ierr = PetscFPTrapPop();CHKERRQ(ierr);
539           ierr = MatSetValues(S_Ej_inv_all,subset_size,dummy_idx,subset_size,dummy_idx,vals2,INSERT_VALUES);CHKERRQ(ierr);
540           ierr = MatDenseRestoreArray(sub_schurs->S_Ej[i],&vals2);CHKERRQ(ierr);
541         }
542         ierr = MatSetValues(S_Ej_tilda_all,subset_size,dummy_idx,subset_size,dummy_idx,vals,INSERT_VALUES);CHKERRQ(ierr);
543         ierr = MatDenseRestoreArray(sub_schurs->S_Ej_tilda[i],&vals);CHKERRQ(ierr);
544       } else {
545         ierr = MatDestroy(&sub_schurs->S_Ej_tilda[i]);CHKERRQ(ierr);
546       }
547       ierr = ISDestroy(&is_E);CHKERRQ(ierr);
548       local_size += subset_size;
549     }
550     ierr = PetscFree(dummy_idx);CHKERRQ(ierr);
551   }
552   ierr = PetscFree(nnz);CHKERRQ(ierr);
553   ierr = MatDestroy(&S_all);CHKERRQ(ierr);
554   ierr = MatAssemblyBegin(sub_schurs->S_Ej_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
555   ierr = MatAssemblyEnd(sub_schurs->S_Ej_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
556   if (compute_Stilda) {
557     ierr = MatAssemblyBegin(S_Ej_tilda_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
558     ierr = MatAssemblyEnd(S_Ej_tilda_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
559     if (deluxe) {
560       ierr = MatAssemblyBegin(S_Ej_inv_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
561       ierr = MatAssemblyEnd(S_Ej_inv_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
562     }
563   }
564 
565   /* Global matrix of all assembled Schur on subsets */
566   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);
567   ierr = ISLocalToGlobalMappingCreate(PetscObjectComm((PetscObject)sub_schurs->l2gmap),1,local_size,all_local_idx_G,PETSC_COPY_VALUES,&l2gmap_subsets);CHKERRQ(ierr);
568   ierr = MatCreateIS(PetscObjectComm((PetscObject)sub_schurs->l2gmap),1,PETSC_DECIDE,PETSC_DECIDE,global_size,global_size,l2gmap_subsets,&work_mat);CHKERRQ(ierr);
569   ierr = ISLocalToGlobalMappingDestroy(&l2gmap_subsets);CHKERRQ(ierr);
570   ierr = MatISSetLocalMat(work_mat,sub_schurs->S_Ej_all);CHKERRQ(ierr);
571   ierr = MatCreate(PetscObjectComm((PetscObject)work_mat),&global_schur_subsets);CHKERRQ(ierr);
572   ierr = MatSetSizes(global_schur_subsets,PETSC_DECIDE,PETSC_DECIDE,global_size,global_size);CHKERRQ(ierr);
573   ierr = MatSetType(global_schur_subsets,MATMPIAIJ);CHKERRQ(ierr);
574   ierr = MatISSetMPIXAIJPreallocation_Private(work_mat,global_schur_subsets,PETSC_TRUE);CHKERRQ(ierr);
575   ierr = MatISGetMPIXAIJ(work_mat,MAT_REUSE_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
576   /* Get local part of (\sum_j S_Ej) */
577   ierr = PetscFree(all_local_idx_N);CHKERRQ(ierr);
578   ierr = ISCreateGeneral(PetscObjectComm((PetscObject)sub_schurs->l2gmap),local_size,all_local_idx_G,PETSC_OWN_POINTER,&temp_is);CHKERRQ(ierr);
579   if (sub_schurs->sum_S_Ej_all) {
580     ierr = MatGetSubMatrixUnsorted(global_schur_subsets,temp_is,temp_is,MAT_REUSE_MATRIX,&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
581   } else {
582     ierr = MatGetSubMatrixUnsorted(global_schur_subsets,temp_is,temp_is,MAT_INITIAL_MATRIX,&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
583   }
584 
585   if (Stilda_computed) {
586     ierr = MatISSetLocalMat(work_mat,S_Ej_tilda_all);CHKERRQ(ierr);
587     ierr = MatISGetMPIXAIJ(work_mat,MAT_REUSE_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
588     if (sub_schurs->sum_S_Ej_tilda_all) {
589       ierr = MatGetSubMatrixUnsorted(global_schur_subsets,temp_is,temp_is,MAT_REUSE_MATRIX,&sub_schurs->sum_S_Ej_tilda_all);CHKERRQ(ierr);
590     } else {
591       ierr = MatGetSubMatrixUnsorted(global_schur_subsets,temp_is,temp_is,MAT_INITIAL_MATRIX,&sub_schurs->sum_S_Ej_tilda_all);CHKERRQ(ierr);
592     }
593     if (deluxe) {
594       PetscInt    cum;
595       PetscScalar *array,*array2;
596       ierr = MatISSetLocalMat(work_mat,S_Ej_inv_all);CHKERRQ(ierr);
597       ierr = MatISGetMPIXAIJ(work_mat,MAT_REUSE_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
598       if (sub_schurs->sum_S_Ej_inv_all) {
599         ierr = MatGetSubMatrixUnsorted(global_schur_subsets,temp_is,temp_is,MAT_REUSE_MATRIX,&sub_schurs->sum_S_Ej_inv_all);CHKERRQ(ierr);
600       } else {
601         ierr = MatGetSubMatrixUnsorted(global_schur_subsets,temp_is,temp_is,MAT_INITIAL_MATRIX,&sub_schurs->sum_S_Ej_inv_all);CHKERRQ(ierr);
602       }
603       /* invert blocks of sum_S_Ej_inv_all */
604       ierr = MatSeqAIJGetArray(sub_schurs->sum_S_Ej_inv_all,&array);CHKERRQ(ierr);
605       ierr = MatSeqAIJGetArray(sub_schurs->sum_S_Ej_tilda_all,&array2);CHKERRQ(ierr);
606       cum = 0;
607       for (i=0;i<sub_schurs->n_subs;i++) {
608         ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
609         if (PetscBTLookup(sub_schurs->computed_Stilda_subs,i)) {
610           /* need to be optimized (cholesky) */
611           ierr = PetscBLASIntCast(subset_size,&B_N);CHKERRQ(ierr);
612           ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
613           PetscStackCallBLAS("LAPACKgetrf",LAPACKgetrf_(&B_N,&B_N,array+cum,&B_N,pivots,&B_ierr));
614           if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRF Lapack routine %d",(int)B_ierr);
615           PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,array+cum,&B_N,pivots,work,&B_lwork,&B_ierr));
616           if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRI Lapack routine %d",(int)B_ierr);
617           PetscStackCallBLAS("LAPACKgetrf",LAPACKgetrf_(&B_N,&B_N,array2+cum,&B_N,pivots,&B_ierr));
618           if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRF Lapack routine %d",(int)B_ierr);
619           PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,array2+cum,&B_N,pivots,work,&B_lwork,&B_ierr));
620           if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRI Lapack routine %d",(int)B_ierr);
621           ierr = PetscFPTrapPop();CHKERRQ(ierr);
622         }
623         cum += subset_size*subset_size;
624       }
625       ierr = MatSeqAIJRestoreArray(sub_schurs->sum_S_Ej_inv_all,&array);CHKERRQ(ierr);
626       ierr = MatSeqAIJRestoreArray(sub_schurs->sum_S_Ej_tilda_all,&array2);CHKERRQ(ierr);
627     }
628   }
629 
630   ierr = PetscFree2(work,pivots);CHKERRQ(ierr);
631   ierr = MatDestroy(&global_schur_subsets);CHKERRQ(ierr);
632   ierr = MatDestroy(&S_Ej_tilda_all);CHKERRQ(ierr);
633   ierr = MatDestroy(&S_Ej_inv_all);CHKERRQ(ierr);
634   ierr = MatDestroy(&work_mat);CHKERRQ(ierr);
635   ierr = ISDestroy(&temp_is);CHKERRQ(ierr);
636   PetscFunctionReturn(0);
637 }
638 
639 #undef __FUNCT__
640 #define __FUNCT__ "PCBDDCSubSchursInit"
641 PetscErrorCode PCBDDCSubSchursInit(PCBDDCSubSchurs sub_schurs, Mat A, Mat S, IS is_I, IS is_B, PCBDDCGraph graph, ISLocalToGlobalMapping BtoNmap, PetscInt seqthreshold)
642 {
643   IS                  *faces,*edges,*all_cc,vertices;
644   PetscInt            *index_sequential,*index_parallel;
645   PetscInt            *auxlocal_sequential,*auxlocal_parallel;
646   PetscInt            *auxglobal_sequential,*auxglobal_parallel;
647   PetscInt            *auxmapping;
648   PetscInt            i,max_subset_size;
649   PetscInt            n_sequential_problems,n_local_sequential_problems,n_parallel_problems,n_local_parallel_problems;
650   PetscInt            n_faces,n_edges,n_all_cc;
651   PetscBool           is_sorted;
652   PetscErrorCode  ierr;
653 
654   PetscFunctionBegin;
655   ierr = ISSorted(is_I,&is_sorted);CHKERRQ(ierr);
656   if (!is_sorted) {
657     SETERRQ(PetscObjectComm((PetscObject)is_I),PETSC_ERR_PLIB,"IS for I dofs should be shorted");
658   }
659   ierr = ISSorted(is_B,&is_sorted);CHKERRQ(ierr);
660   if (!is_sorted) {
661     SETERRQ(PetscObjectComm((PetscObject)is_B),PETSC_ERR_PLIB,"IS for B dofs should be shorted");
662   }
663 
664   /* reset any previous data */
665   ierr = PCBDDCSubSchursReset(sub_schurs);CHKERRQ(ierr);
666 
667   /* get index sets for faces and edges */
668   ierr = PCBDDCGraphGetCandidatesIS(graph,&n_faces,&faces,&n_edges,&edges,&vertices);CHKERRQ(ierr);
669   n_all_cc = n_faces+n_edges;
670   ierr = PetscBTCreate(n_all_cc,&sub_schurs->is_edge);CHKERRQ(ierr);
671   ierr = PetscBTCreate(n_all_cc,&sub_schurs->computed_Stilda_subs);CHKERRQ(ierr);
672   ierr = PetscMalloc1(n_all_cc,&all_cc);CHKERRQ(ierr);
673   for (i=0;i<n_faces;i++) {
674     all_cc[i] = faces[i];
675   }
676   for (i=0;i<n_edges;i++) {
677     all_cc[n_faces+i] = edges[i];
678     ierr = PetscBTSet(sub_schurs->is_edge,n_faces+i);CHKERRQ(ierr);
679   }
680   ierr = PetscFree(faces);CHKERRQ(ierr);
681   ierr = PetscFree(edges);CHKERRQ(ierr);
682 
683   /* map interface's subsets */
684   max_subset_size = 0;
685   for (i=0;i<n_all_cc;i++) {
686     PetscInt subset_size;
687     ierr = ISGetLocalSize(all_cc[i],&subset_size);CHKERRQ(ierr);
688     max_subset_size = PetscMax(max_subset_size,subset_size);
689   }
690   ierr = PetscMalloc1(max_subset_size,&auxmapping);CHKERRQ(ierr);
691   ierr = PetscMalloc2(graph->ncc,&auxlocal_sequential,
692                       graph->ncc,&auxlocal_parallel);CHKERRQ(ierr);
693   ierr = PetscMalloc2(graph->ncc,&index_sequential,
694                       graph->ncc,&index_parallel);CHKERRQ(ierr);
695 
696   /* if threshold is negative uses all sequential problems (possibly using MUMPS) */
697   sub_schurs->use_mumps = PETSC_FALSE;
698   if (seqthreshold < 0) {
699     seqthreshold = max_subset_size;
700 #if defined(PETSC_HAVE_MUMPS)
701     sub_schurs->use_mumps = !!A;
702 #endif
703   }
704 
705 
706   /* determine which problem has to be solved in parallel or sequentially */
707   n_local_sequential_problems = 0;
708   n_local_parallel_problems = 0;
709   for (i=0;i<n_all_cc;i++) {
710     PetscInt       subset_size,j,min_loc = 0;
711     const PetscInt *idxs;
712 
713     ierr = ISGetLocalSize(all_cc[i],&subset_size);CHKERRQ(ierr);
714     ierr = ISGetIndices(all_cc[i],&idxs);CHKERRQ(ierr);
715     ierr = ISLocalToGlobalMappingApply(graph->l2gmap,subset_size,idxs,auxmapping);CHKERRQ(ierr);
716     for (j=1;j<subset_size;j++) {
717       if (auxmapping[j]<auxmapping[min_loc]) {
718         min_loc = j;
719       }
720     }
721     if (subset_size > seqthreshold) {
722       index_parallel[n_local_parallel_problems] = i;
723       auxlocal_parallel[n_local_parallel_problems] = idxs[min_loc];
724       n_local_parallel_problems++;
725     } else {
726       index_sequential[n_local_sequential_problems] = i;
727       auxlocal_sequential[n_local_sequential_problems] = idxs[min_loc];
728       n_local_sequential_problems++;
729     }
730     ierr = ISRestoreIndices(all_cc[i],&idxs);CHKERRQ(ierr);
731   }
732 
733   /* Number parallel problems */
734   auxglobal_parallel = 0;
735   ierr = PCBDDCSubsetNumbering(PetscObjectComm((PetscObject)graph->l2gmap),graph->l2gmap,n_local_parallel_problems,auxlocal_parallel,PETSC_NULL,&n_parallel_problems,&auxglobal_parallel);CHKERRQ(ierr);
736 
737   /* Number sequential problems */
738   auxglobal_sequential = 0;
739   ierr = PCBDDCSubsetNumbering(PetscObjectComm((PetscObject)graph->l2gmap),graph->l2gmap,n_local_sequential_problems,auxlocal_sequential,PETSC_NULL,&n_sequential_problems,&auxglobal_sequential);CHKERRQ(ierr);
740 
741   /* update info in sub_schurs */
742   if (sub_schurs->use_mumps && A) {
743     ierr = PetscObjectReference((PetscObject)A);CHKERRQ(ierr);
744     sub_schurs->A = A;
745   }
746   ierr = PetscObjectReference((PetscObject)S);CHKERRQ(ierr);
747   sub_schurs->S = S;
748   ierr = PetscObjectReference((PetscObject)is_I);CHKERRQ(ierr);
749   sub_schurs->is_I = is_I;
750   ierr = PetscObjectReference((PetscObject)is_B);CHKERRQ(ierr);
751   sub_schurs->is_B = is_B;
752   ierr = PetscObjectReference((PetscObject)graph->l2gmap);CHKERRQ(ierr);
753   sub_schurs->l2gmap = graph->l2gmap;
754   ierr = PetscObjectReference((PetscObject)BtoNmap);CHKERRQ(ierr);
755   sub_schurs->BtoNmap = BtoNmap;
756   sub_schurs->n_subs_seq = n_local_sequential_problems;
757   sub_schurs->n_subs_par = n_local_parallel_problems;
758   sub_schurs->n_subs_seq_g = n_sequential_problems;
759   sub_schurs->n_subs_par_g = n_parallel_problems;
760   sub_schurs->n_subs = sub_schurs->n_subs_seq + sub_schurs->n_subs_par;
761   sub_schurs->is_subs = all_cc;
762   if (!sub_schurs->use_mumps) { /* for adaptive selection */
763     for (i=0;i<sub_schurs->n_subs;i++) {
764       ierr = ISSort(sub_schurs->is_subs[i]);CHKERRQ(ierr);
765     }
766   }
767   sub_schurs->is_Ej_com = vertices;
768   sub_schurs->index_sequential = index_sequential;
769   sub_schurs->index_parallel = index_parallel;
770   sub_schurs->auxglobal_sequential = auxglobal_sequential;
771   sub_schurs->auxglobal_parallel = auxglobal_parallel;
772 
773 
774   /* allocate space for schur complements */
775   ierr = PetscCalloc2(sub_schurs->n_subs,&sub_schurs->S_Ej,
776                       sub_schurs->n_subs,&sub_schurs->S_Ej_tilda);CHKERRQ(ierr);
777   sub_schurs->S_Ej_all = NULL;
778   sub_schurs->sum_S_Ej_all = NULL;
779   sub_schurs->sum_S_Ej_inv_all = NULL;
780   sub_schurs->sum_S_Ej_tilda_all = NULL;
781   sub_schurs->is_Ej_all = NULL;
782 
783   /* free workspace */
784   ierr = PetscFree(auxmapping);CHKERRQ(ierr);
785   ierr = PetscFree2(auxlocal_sequential,auxlocal_parallel);CHKERRQ(ierr);
786 
787   PetscFunctionReturn(0);
788 }
789 
790 #undef __FUNCT__
791 #define __FUNCT__ "PCBDDCSubSchursCreate"
792 PetscErrorCode PCBDDCSubSchursCreate(PCBDDCSubSchurs *sub_schurs)
793 {
794   PCBDDCSubSchurs schurs_ctx;
795   PetscErrorCode  ierr;
796 
797   PetscFunctionBegin;
798   ierr = PetscNew(&schurs_ctx);CHKERRQ(ierr);
799   schurs_ctx->n_subs = 0;
800   *sub_schurs = schurs_ctx;
801   PetscFunctionReturn(0);
802 }
803 
804 #undef __FUNCT__
805 #define __FUNCT__ "PCBDDCSubSchursDestroy"
806 PetscErrorCode PCBDDCSubSchursDestroy(PCBDDCSubSchurs *sub_schurs)
807 {
808   PetscErrorCode ierr;
809 
810   PetscFunctionBegin;
811   ierr = PCBDDCSubSchursReset(*sub_schurs);CHKERRQ(ierr);
812   ierr = PetscFree(*sub_schurs);CHKERRQ(ierr);
813   PetscFunctionReturn(0);
814 }
815 
816 #undef __FUNCT__
817 #define __FUNCT__ "PCBDDCSubSchursReset"
818 PetscErrorCode PCBDDCSubSchursReset(PCBDDCSubSchurs sub_schurs)
819 {
820   PetscInt       i;
821   PetscErrorCode ierr;
822 
823   PetscFunctionBegin;
824   ierr = MatDestroy(&sub_schurs->A);CHKERRQ(ierr);
825   ierr = MatDestroy(&sub_schurs->S);CHKERRQ(ierr);
826   ierr = ISDestroy(&sub_schurs->is_I);CHKERRQ(ierr);
827   ierr = ISDestroy(&sub_schurs->is_B);CHKERRQ(ierr);
828   ierr = ISLocalToGlobalMappingDestroy(&sub_schurs->l2gmap);CHKERRQ(ierr);
829   ierr = ISLocalToGlobalMappingDestroy(&sub_schurs->BtoNmap);CHKERRQ(ierr);
830   ierr = MatDestroy(&sub_schurs->S_Ej_all);CHKERRQ(ierr);
831   ierr = MatDestroy(&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
832   ierr = MatDestroy(&sub_schurs->sum_S_Ej_inv_all);CHKERRQ(ierr);
833   ierr = MatDestroy(&sub_schurs->sum_S_Ej_tilda_all);CHKERRQ(ierr);
834   ierr = ISDestroy(&sub_schurs->is_Ej_all);CHKERRQ(ierr);
835   ierr = ISDestroy(&sub_schurs->is_Ej_com);CHKERRQ(ierr);
836   ierr = PetscBTDestroy(&sub_schurs->is_edge);CHKERRQ(ierr);
837   ierr = PetscBTDestroy(&sub_schurs->computed_Stilda_subs);CHKERRQ(ierr);
838   for (i=0;i<sub_schurs->n_subs;i++) {
839     ierr = ISDestroy(&sub_schurs->is_subs[i]);CHKERRQ(ierr);
840     ierr = MatDestroy(&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
841     ierr = MatDestroy(&sub_schurs->S_Ej_tilda[i]);CHKERRQ(ierr);
842   }
843   ierr = ISDestroy(&sub_schurs->is_I_layer);CHKERRQ(ierr);
844   if (sub_schurs->n_subs) {
845     ierr = PetscFree(sub_schurs->is_subs);CHKERRQ(ierr);
846     ierr = PetscFree2(sub_schurs->S_Ej,sub_schurs->S_Ej_tilda);CHKERRQ(ierr);
847     ierr = PetscFree2(sub_schurs->index_sequential,sub_schurs->index_parallel);CHKERRQ(ierr);
848     ierr = PetscFree(sub_schurs->auxglobal_sequential);CHKERRQ(ierr);
849     ierr = PetscFree(sub_schurs->auxglobal_parallel);CHKERRQ(ierr);
850   }
851   sub_schurs->n_subs = 0;
852   PetscFunctionReturn(0);
853 }
854 
855 #undef __FUNCT__
856 #define __FUNCT__ "PCBDDCAdjGetNextLayer_Private"
857 PETSC_STATIC_INLINE PetscErrorCode PCBDDCAdjGetNextLayer_Private(PetscInt* queue_tip,PetscInt n_prev,PetscBT touched,PetscInt* xadj,PetscInt* adjncy,PetscInt* n_added)
858 {
859   PetscInt       i,j,n;
860   PetscErrorCode ierr;
861 
862   PetscFunctionBegin;
863   n = 0;
864   for (i=-n_prev;i<0;i++) {
865     PetscInt start_dof = queue_tip[i];
866     for (j=xadj[start_dof];j<xadj[start_dof+1];j++) {
867       PetscInt dof = adjncy[j];
868       if (!PetscBTLookup(touched,dof)) {
869         ierr = PetscBTSet(touched,dof);CHKERRQ(ierr);
870         queue_tip[n] = dof;
871         n++;
872       }
873     }
874   }
875   *n_added = n;
876   PetscFunctionReturn(0);
877 }
878