xref: /petsc/src/ksp/pc/impls/bddc/bddcschurs.c (revision 4e57e00dd1d92684f19b1cbf619e6af3666f4821)
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,PetscBool,MatReuse,Mat*);
7 
8 #undef __FUNCT__
9 #define __FUNCT__ "PCBDDCComputeExplicitSchur"
10 static PetscErrorCode PCBDDCComputeExplicitSchur(Mat M, PetscBool issym, MatReuse reuse, 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   PetscInt       n_I;
18   PetscMPIInt    size;
19   PetscErrorCode ierr;
20 
21   PetscFunctionBegin;
22   ierr = MPI_Comm_size(PetscObjectComm((PetscObject)M),&size);CHKERRQ(ierr);
23   if (size != 1) {
24     SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Not for parallel matrices");
25   }
26   if (reuse == MAT_REUSE_MATRIX) {
27     PetscBool Sdense;
28 
29     ierr = PetscObjectTypeCompare((PetscObject)*S, MATSEQDENSE, &Sdense);CHKERRQ(ierr);
30     if (!Sdense) {
31       SETERRQ(PetscObjectComm((PetscObject)M),PETSC_ERR_SUP,"S should dense");
32     }
33   }
34   ierr = MatSchurComplementGetSubMatrices(M, NULL, NULL, &B, &C, &D);CHKERRQ(ierr);
35   ierr = MatSchurComplementGetKSP(M, &ksp);CHKERRQ(ierr);
36   ierr = KSPGetPC(ksp, &pc);CHKERRQ(ierr);
37   ierr = PetscObjectTypeCompare((PetscObject) pc, PCLU, &isLU);CHKERRQ(ierr);
38   ierr = PetscObjectTypeCompare((PetscObject) pc, PCILU, &isILU);CHKERRQ(ierr);
39   ierr = PetscObjectTypeCompare((PetscObject) pc, PCCHOLESKY, &isCHOL);CHKERRQ(ierr);
40   ierr = PetscObjectTypeCompare((PetscObject) B, MATSEQDENSE, &Bdense);CHKERRQ(ierr);
41   ierr = PetscObjectTypeCompare((PetscObject) C, MATSEQDENSE, &Cdense);CHKERRQ(ierr);
42   ierr = MatGetSize(B,&n_I,NULL);CHKERRQ(ierr);
43   if (n_I) {
44     if (!Bdense) {
45       ierr = MatConvert(B, MATSEQDENSE, MAT_INITIAL_MATRIX, &Bd);CHKERRQ(ierr);
46     } else {
47       Bd = B;
48     }
49 
50     if (isLU || isILU || isCHOL) {
51       Mat fact;
52       ierr = KSPSetUp(ksp);CHKERRQ(ierr);
53       ierr = PCFactorGetMatrix(pc, &fact);CHKERRQ(ierr);
54       ierr = MatDuplicate(Bd, MAT_DO_NOT_COPY_VALUES, &AinvBd);CHKERRQ(ierr);
55       ierr = MatMatSolve(fact, Bd, AinvBd);CHKERRQ(ierr);
56     } else {
57       PetscBool ex = PETSC_TRUE;
58 
59       if (ex) {
60         Mat Ainvd;
61 
62         ierr = PCComputeExplicitOperator(pc, &Ainvd);CHKERRQ(ierr);
63         ierr = MatMatMult(Ainvd, Bd, MAT_INITIAL_MATRIX, fill, &AinvBd);CHKERRQ(ierr);
64         ierr = MatDestroy(&Ainvd);CHKERRQ(ierr);
65       } else {
66         Vec         sol,rhs;
67         PetscScalar *arrayrhs,*arraysol;
68         PetscInt    i,nrhs,n;
69 
70         ierr = MatDuplicate(Bd, MAT_DO_NOT_COPY_VALUES, &AinvBd);CHKERRQ(ierr);
71         ierr = MatGetSize(Bd,&n,&nrhs);CHKERRQ(ierr);
72         ierr = MatDenseGetArray(Bd,&arrayrhs);CHKERRQ(ierr);
73         ierr = MatDenseGetArray(AinvBd,&arraysol);CHKERRQ(ierr);
74         ierr = KSPGetSolution(ksp,&sol);CHKERRQ(ierr);
75         ierr = KSPGetRhs(ksp,&rhs);CHKERRQ(ierr);
76         for (i=0;i<nrhs;i++) {
77           ierr = VecPlaceArray(rhs,arrayrhs+i*n);CHKERRQ(ierr);
78           ierr = VecPlaceArray(sol,arraysol+i*n);CHKERRQ(ierr);
79           ierr = KSPSolve(ksp,rhs,sol);CHKERRQ(ierr);
80           ierr = VecResetArray(rhs);CHKERRQ(ierr);
81           ierr = VecResetArray(sol);CHKERRQ(ierr);
82         }
83         ierr = MatDenseRestoreArray(Bd,&arrayrhs);CHKERRQ(ierr);
84         ierr = MatDenseRestoreArray(AinvBd,&arrayrhs);CHKERRQ(ierr);
85       }
86     }
87     if (!Bdense & !issym) {
88       ierr = MatDestroy(&Bd);CHKERRQ(ierr);
89     }
90 
91     if (!issym) {
92       if (!Cdense) {
93         ierr = MatConvert(C, MATSEQDENSE, MAT_INITIAL_MATRIX, &Cd);CHKERRQ(ierr);
94       } else {
95         Cd = C;
96       }
97       ierr = MatMatMult(Cd, AinvBd, reuse, fill, S);CHKERRQ(ierr);
98       if (!Cdense) {
99         ierr = MatDestroy(&Cd);CHKERRQ(ierr);
100       }
101     } else {
102       ierr = MatTransposeMatMult(Bd, AinvBd, reuse, fill, S);CHKERRQ(ierr);
103       if (!Bdense) {
104         ierr = MatDestroy(&Bd);CHKERRQ(ierr);
105       }
106     }
107     ierr = MatDestroy(&AinvBd);CHKERRQ(ierr);
108   }
109 
110   if (D) {
111     Mat       Dd;
112     PetscBool Ddense;
113 
114     ierr = PetscObjectTypeCompare((PetscObject)D,MATSEQDENSE,&Ddense);CHKERRQ(ierr);
115     if (!Ddense) {
116       ierr = MatConvert(D, MATSEQDENSE, MAT_INITIAL_MATRIX, &Dd);CHKERRQ(ierr);
117     } else {
118       Dd = D;
119     }
120     if (n_I) {
121       ierr = MatAYPX(*S,-1.0,Dd,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
122     } else {
123       if (reuse == MAT_INITIAL_MATRIX) {
124         ierr = MatDuplicate(Dd,MAT_COPY_VALUES,S);CHKERRQ(ierr);
125       } else {
126         ierr = MatCopy(Dd,*S,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
127       }
128     }
129     if (!Ddense) {
130       ierr = MatDestroy(&Dd);CHKERRQ(ierr);
131     }
132   } else {
133     ierr = MatScale(*S,-1.0);CHKERRQ(ierr);
134   }
135   PetscFunctionReturn(0);
136 }
137 
138 #undef __FUNCT__
139 #define __FUNCT__ "PCBDDCSubSchursSetUp"
140 PetscErrorCode PCBDDCSubSchursSetUp(PCBDDCSubSchurs sub_schurs, PetscInt xadj[], PetscInt adjncy[], PetscInt nlayers, PetscBool compute_Stilda, PetscBool deluxe, PetscBool invert_Stildas, PetscBool use_edges, PetscBool use_faces)
141 {
142   Mat                    A_II,A_IB,A_BI,A_BB;
143   Mat                    AE_II,*AE_IE,*AE_EI,*AE_EE;
144   Mat                    S_all,S_all_inv;
145   Mat                    global_schur_subsets,work_mat;
146   Mat                    S_Ej_tilda_all,S_Ej_inv_all;
147   ISLocalToGlobalMapping l2gmap_subsets;
148   IS                     is_I,*is_subset_B,temp_is;
149   PetscInt               *nnz,*all_local_idx_G,*all_local_idx_N;
150   PetscInt               i,subset_size,max_subset_size_seq;
151   PetscInt               extra,local_size,global_size;
152   PetscBLASInt           B_N,B_ierr,B_lwork,*pivots;
153   PetscScalar            *Bwork;
154   PetscErrorCode         ierr;
155 
156   PetscFunctionBegin;
157   /* get Schur complement matrices */
158   if (!sub_schurs->use_mumps) {
159     PetscBool isseqaij;
160 
161     if (compute_Stilda) {
162       SETERRQ(PetscObjectComm((PetscObject)sub_schurs->l2gmap),PETSC_ERR_SUP,"Adaptive selection of constraints requires MUMPS");
163     }
164     ierr = MatSchurComplementGetSubMatrices(sub_schurs->S,&A_II,NULL,&A_IB,&A_BI,&A_BB);CHKERRQ(ierr);
165     ierr = PetscObjectTypeCompare((PetscObject)A_BB,MATSEQAIJ,&isseqaij);CHKERRQ(ierr);
166     if (!isseqaij) {
167       ierr = MatConvert(A_BB,MATSEQAIJ,MAT_REUSE_MATRIX,&A_BB);CHKERRQ(ierr);
168       ierr = MatConvert(A_IB,MATSEQAIJ,MAT_REUSE_MATRIX,&A_IB);CHKERRQ(ierr);
169       ierr = MatConvert(A_BI,MATSEQAIJ,MAT_REUSE_MATRIX,&A_BI);CHKERRQ(ierr);
170     }
171     ierr = PetscMalloc4(sub_schurs->n_subs,&is_subset_B,
172                         sub_schurs->n_subs,&AE_IE,
173                         sub_schurs->n_subs,&AE_EI,
174                         sub_schurs->n_subs,&AE_EE);CHKERRQ(ierr);
175   } else {
176     is_subset_B = NULL;
177     AE_IE = NULL;
178     AE_EI = NULL;
179     AE_EE = NULL;
180   }
181 
182   /* determine interior problems */
183   ierr = ISDestroy(&sub_schurs->is_I_layer);CHKERRQ(ierr);
184   ierr = ISGetLocalSize(sub_schurs->is_I,&i);CHKERRQ(ierr);
185   if (nlayers >= 0 && i) { /* Interior problems can be different from the original one */
186     PetscBT                touched;
187     const PetscInt*        idx_B;
188     PetscInt               n_I,n_B,n_local_dofs,n_prev_added,j,layer,*local_numbering;
189 
190     if (xadj == NULL || adjncy == NULL) {
191       SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Cannot request layering without adjacency");
192     }
193     /* get sizes */
194     ierr = ISGetLocalSize(sub_schurs->is_I,&n_I);CHKERRQ(ierr);
195     ierr = ISGetLocalSize(sub_schurs->is_B,&n_B);CHKERRQ(ierr);
196 
197     ierr = PetscMalloc1(n_I+n_B,&local_numbering);CHKERRQ(ierr);
198     ierr = PetscBTCreate(n_I+n_B,&touched);CHKERRQ(ierr);
199     ierr = PetscBTMemzero(n_I+n_B,touched);CHKERRQ(ierr);
200 
201     /* all boundary dofs must be skipped when adding layers */
202     ierr = ISGetIndices(sub_schurs->is_B,&idx_B);CHKERRQ(ierr);
203     for (j=0;j<n_B;j++) {
204       ierr = PetscBTSet(touched,idx_B[j]);CHKERRQ(ierr);
205     }
206     ierr = PetscMemcpy(local_numbering,idx_B,n_B*sizeof(PetscInt));CHKERRQ(ierr);
207     ierr = ISRestoreIndices(sub_schurs->is_B,&idx_B);CHKERRQ(ierr);
208 
209     /* add prescribed number of layers of dofs */
210     n_local_dofs = n_B;
211     n_prev_added = n_B;
212     for (layer=0;layer<nlayers;layer++) {
213       PetscInt n_added;
214       if (n_local_dofs == n_I+n_B) break;
215       if (n_local_dofs > n_I+n_B) {
216         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);
217       }
218       ierr = PCBDDCAdjGetNextLayer_Private(local_numbering+n_local_dofs,n_prev_added,touched,xadj,adjncy,&n_added);CHKERRQ(ierr);
219       n_prev_added = n_added;
220       n_local_dofs += n_added;
221       if (!n_added) break;
222     }
223     ierr = PetscBTDestroy(&touched);CHKERRQ(ierr);
224 
225     /* IS for I layer dofs in original numbering */
226     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);
227     ierr = PetscFree(local_numbering);CHKERRQ(ierr);
228     ierr = ISSort(sub_schurs->is_I_layer);CHKERRQ(ierr);
229     /* IS for I layer dofs in I numbering */
230     if (!sub_schurs->use_mumps) {
231       ISLocalToGlobalMapping ItoNmap;
232       ierr = ISLocalToGlobalMappingCreateIS(sub_schurs->is_I,&ItoNmap);CHKERRQ(ierr);
233       ierr = ISGlobalToLocalMappingApplyIS(ItoNmap,IS_GTOLM_DROP,sub_schurs->is_I_layer,&is_I);CHKERRQ(ierr);
234       ierr = ISLocalToGlobalMappingDestroy(&ItoNmap);CHKERRQ(ierr);
235 
236       /* II block */
237       ierr = MatGetSubMatrix(A_II,is_I,is_I,MAT_INITIAL_MATRIX,&AE_II);CHKERRQ(ierr);
238     }
239   } else {
240     PetscInt n_I;
241 
242     /* IS for I dofs in original numbering */
243     ierr = PetscObjectReference((PetscObject)sub_schurs->is_I);CHKERRQ(ierr);
244     sub_schurs->is_I_layer = sub_schurs->is_I;
245 
246     /* IS for I dofs in I numbering (strided 1) */
247     if (!sub_schurs->use_mumps) {
248       ierr = ISGetSize(sub_schurs->is_I,&n_I);CHKERRQ(ierr);
249       ierr = ISCreateStride(PetscObjectComm((PetscObject)sub_schurs->is_I),n_I,0,1,&is_I);CHKERRQ(ierr);
250 
251       /* II block is the same */
252       ierr = PetscObjectReference((PetscObject)A_II);CHKERRQ(ierr);
253       AE_II = A_II;
254     }
255   }
256   /* Get info on subset sizes and sum of all subsets sizes */
257   max_subset_size_seq = 0;
258   local_size = 0;
259   for (i=0;i<sub_schurs->n_subs_seq;i++) {
260     PetscInt j = sub_schurs->index_sequential[i];
261     ierr = ISGetLocalSize(sub_schurs->is_subs[j],&subset_size);CHKERRQ(ierr);
262     max_subset_size_seq = PetscMax(subset_size,max_subset_size_seq);
263     local_size += subset_size;
264   }
265 
266   /* Work arrays for local indices */
267   extra = 0;
268   if (sub_schurs->use_mumps) {
269     ierr = ISGetLocalSize(sub_schurs->is_I_layer,&extra);CHKERRQ(ierr);
270   }
271   ierr = PetscMalloc1(local_size+extra,&all_local_idx_N);CHKERRQ(ierr);
272   if (extra) {
273     const PetscInt *idxs;
274     ierr = ISGetIndices(sub_schurs->is_I_layer,&idxs);CHKERRQ(ierr);
275     ierr = PetscMemcpy(all_local_idx_N,idxs,extra*sizeof(PetscInt));CHKERRQ(ierr);
276     ierr = ISRestoreIndices(sub_schurs->is_I_layer,&idxs);CHKERRQ(ierr);
277   }
278   ierr = PetscMalloc1(local_size,&nnz);CHKERRQ(ierr);
279 
280   /* Get local indices in local numbering */
281   local_size = 0;
282   for (i=0;i<sub_schurs->n_subs_seq;i++) {
283     PetscInt j;
284     const    PetscInt *idxs;
285 
286     PetscInt local_problem_index = sub_schurs->index_sequential[i];
287     ierr = ISGetLocalSize(sub_schurs->is_subs[local_problem_index],&subset_size);CHKERRQ(ierr);
288     ierr = ISGetIndices(sub_schurs->is_subs[local_problem_index],&idxs);CHKERRQ(ierr);
289     /* subset indices in local numbering */
290     ierr = PetscMemcpy(all_local_idx_N+local_size+extra,idxs,subset_size*sizeof(PetscInt));CHKERRQ(ierr);
291     ierr = ISRestoreIndices(sub_schurs->is_subs[local_problem_index],&idxs);CHKERRQ(ierr);
292     for (j=0;j<subset_size;j++) nnz[local_size+j] = subset_size;
293     local_size += subset_size;
294   }
295 
296   S_all = NULL;
297   S_all_inv = NULL;
298   S_Ej_tilda_all = NULL;
299   S_Ej_inv_all = NULL;
300   sub_schurs->is_hermitian = PETSC_FALSE;
301   sub_schurs->is_posdef = PETSC_FALSE;
302   if (sub_schurs->A) {
303     ierr = MatIsHermitian(sub_schurs->A,0.0,&sub_schurs->is_hermitian);CHKERRQ(ierr);
304     if (sub_schurs->is_hermitian) {
305       PetscScalar val;
306       Vec         vec1,vec2;
307 
308       ierr = MatCreateVecs(sub_schurs->A,&vec1,&vec2);CHKERRQ(ierr);
309       ierr = VecSetRandom(vec1,NULL);
310       ierr = VecCopy(vec1,vec2);CHKERRQ(ierr);
311       ierr = MatMult(sub_schurs->A,vec2,vec1);CHKERRQ(ierr);
312       ierr = VecDot(vec1,vec2,&val);CHKERRQ(ierr);
313       if (PetscRealPart(val) > 0. && PetscImaginaryPart(val) == 0.) sub_schurs->is_posdef = PETSC_TRUE;
314       ierr = VecDestroy(&vec1);CHKERRQ(ierr);
315       ierr = VecDestroy(&vec2);CHKERRQ(ierr);
316     }
317   }
318   Bwork = NULL;
319   pivots = NULL;
320   if (sub_schurs->n_subs && deluxe && compute_Stilda && !sub_schurs->is_hermitian) { /* workspace needed only for GETRI */
321     PetscScalar lwork;
322 
323     B_lwork = -1;
324     ierr = PetscBLASIntCast(local_size,&B_N);CHKERRQ(ierr);
325     ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
326     PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,Bwork,&B_N,pivots,&lwork,&B_lwork,&B_ierr));
327     ierr = PetscFPTrapPop();CHKERRQ(ierr);
328     if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in query to GETRI Lapack routine %d",(int)B_ierr);
329     ierr = PetscBLASIntCast((PetscInt)PetscRealPart(lwork),&B_lwork);CHKERRQ(ierr);
330     ierr = PetscMalloc2(B_lwork,&Bwork,B_N,&pivots);CHKERRQ(ierr);
331   }
332 
333   /* prepare parallel matrices for summing up properly schurs on subsets */
334   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);
335   ierr = ISLocalToGlobalMappingCreate(PetscObjectComm((PetscObject)sub_schurs->l2gmap),1,local_size,all_local_idx_G,PETSC_COPY_VALUES,&l2gmap_subsets);CHKERRQ(ierr);
336   ierr = MatCreateIS(PetscObjectComm((PetscObject)sub_schurs->l2gmap),1,PETSC_DECIDE,PETSC_DECIDE,global_size,global_size,l2gmap_subsets,&work_mat);CHKERRQ(ierr);
337   ierr = ISLocalToGlobalMappingDestroy(&l2gmap_subsets);CHKERRQ(ierr);
338   ierr = MatCreate(PetscObjectComm((PetscObject)work_mat),&global_schur_subsets);CHKERRQ(ierr);
339   ierr = MatSetSizes(global_schur_subsets,PETSC_DECIDE,PETSC_DECIDE,global_size,global_size);CHKERRQ(ierr);
340   ierr = MatSetType(global_schur_subsets,MATMPIAIJ);CHKERRQ(ierr);
341 
342   if (sub_schurs->n_subs) {
343     if (!sub_schurs->use_mumps) {
344       /* subsets in original and boundary numbering */
345       for (i=0;i<sub_schurs->n_subs;i++) {
346         ierr = ISGlobalToLocalMappingApplyIS(sub_schurs->BtoNmap,IS_GTOLM_DROP,sub_schurs->is_subs[i],&is_subset_B[i]);CHKERRQ(ierr);
347       }
348 
349       /* EE block */
350       for (i=0;i<sub_schurs->n_subs;i++) {
351         ierr = MatGetSubMatrix(A_BB,is_subset_B[i],is_subset_B[i],MAT_INITIAL_MATRIX,&AE_EE[i]);CHKERRQ(ierr);
352       }
353 
354       /* IE block */
355       for (i=0;i<sub_schurs->n_subs;i++) {
356         ierr = MatGetSubMatrix(A_IB,is_I,is_subset_B[i],MAT_INITIAL_MATRIX,&AE_IE[i]);CHKERRQ(ierr);
357       }
358 
359       /* EI block */
360       for (i=0;i<sub_schurs->n_subs;i++) {
361         if (sub_schurs->is_hermitian) {
362           ierr = MatCreateTranspose(AE_IE[i],&AE_EI[i]);CHKERRQ(ierr);
363         } else {
364           ierr = MatGetSubMatrix(A_BI,is_subset_B[i],is_I,MAT_INITIAL_MATRIX,&AE_EI[i]);CHKERRQ(ierr);
365         }
366       }
367 
368       /* setup Schur complements on subset */
369       for (i=0;i<sub_schurs->n_subs;i++) {
370         ierr = MatDestroy(&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
371         ierr = MatCreateSchurComplement(AE_II,AE_II,AE_IE[i],AE_EI[i],AE_EE[i],&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
372         ierr = MatDestroy(&AE_EE[i]);CHKERRQ(ierr);
373         ierr = MatDestroy(&AE_IE[i]);CHKERRQ(ierr);
374         ierr = MatDestroy(&AE_EI[i]);CHKERRQ(ierr);
375         if (AE_II == A_II) { /* we can reuse the same ksp */
376           KSP ksp;
377           ierr = MatSchurComplementGetKSP(sub_schurs->S,&ksp);CHKERRQ(ierr);
378           ierr = MatSchurComplementSetKSP(sub_schurs->S_Ej[i],ksp);CHKERRQ(ierr);
379         } else { /* build new ksp object which inherits ksp and pc types from the original one */
380           KSP      origksp,schurksp;
381           PC       origpc,schurpc;
382           KSPType  ksp_type;
383           PCType   pc_type;
384           PetscInt n_internal;
385 
386           ierr = MatSchurComplementGetKSP(sub_schurs->S,&origksp);CHKERRQ(ierr);
387           ierr = MatSchurComplementGetKSP(sub_schurs->S_Ej[i],&schurksp);CHKERRQ(ierr);
388           ierr = KSPGetType(origksp,&ksp_type);CHKERRQ(ierr);
389           ierr = KSPSetType(schurksp,ksp_type);CHKERRQ(ierr);
390           ierr = KSPGetPC(schurksp,&schurpc);CHKERRQ(ierr);
391           ierr = KSPGetPC(origksp,&origpc);CHKERRQ(ierr);
392           ierr = PCGetType(origpc,&pc_type);CHKERRQ(ierr);
393           ierr = PCSetType(schurpc,pc_type);CHKERRQ(ierr);
394           ierr = ISGetSize(is_I,&n_internal);CHKERRQ(ierr);
395           if (n_internal) { /* UMFPACK gives error with 0 sized problems */
396             MatSolverPackage solver=NULL;
397             ierr = PCFactorGetMatSolverPackage(origpc,(const MatSolverPackage*)&solver);CHKERRQ(ierr);
398             if (solver) {
399               ierr = PCFactorSetMatSolverPackage(schurpc,solver);CHKERRQ(ierr);
400             }
401           }
402           ierr = KSPSetUp(schurksp);CHKERRQ(ierr);
403         }
404       }
405       /* free */
406       ierr = ISDestroy(&is_I);CHKERRQ(ierr);
407       ierr = MatDestroy(&AE_II);CHKERRQ(ierr);
408       for (i=0;i<sub_schurs->n_subs;i++) {
409         ierr = ISDestroy(&is_subset_B[i]);CHKERRQ(ierr);
410       }
411       ierr = PetscFree4(is_subset_B,AE_IE,AE_EI,AE_EE);CHKERRQ(ierr);
412 #if defined(PETSC_HAVE_MUMPS)
413     } else {
414       Mat           A,F;
415       IS            is_A_all;
416       PetscInt      *idxs_schur,n_I;
417 
418       /* get working mat */
419       ierr = ISGetLocalSize(sub_schurs->is_I_layer,&n_I);CHKERRQ(ierr);
420       ierr = ISCreateGeneral(PETSC_COMM_SELF,local_size+n_I,all_local_idx_N,PETSC_COPY_VALUES,&is_A_all);CHKERRQ(ierr);
421       ierr = MatGetSubMatrixUnsorted(sub_schurs->A,is_A_all,is_A_all,&A);CHKERRQ(ierr);
422       ierr = ISDestroy(&is_A_all);CHKERRQ(ierr);
423 
424       if (n_I) {
425         if (sub_schurs->is_hermitian && sub_schurs->is_posdef) {
426           ierr = MatGetFactor(A,MATSOLVERMUMPS,MAT_FACTOR_CHOLESKY,&F);CHKERRQ(ierr);
427         } else {
428           ierr = MatGetFactor(A,MATSOLVERMUMPS,MAT_FACTOR_LU,&F);CHKERRQ(ierr);
429         }
430 
431         /* subsets ordered last */
432         ierr = PetscMalloc1(local_size,&idxs_schur);CHKERRQ(ierr);
433         for (i=0;i<local_size;i++) {
434           idxs_schur[i] = n_I+i+1;
435         }
436         ierr = MatMumpsSetSchurIndices(F,local_size,idxs_schur);CHKERRQ(ierr);
437         ierr = PetscFree(idxs_schur);CHKERRQ(ierr);
438 
439         /* factorization step */
440         if (sub_schurs->is_hermitian && sub_schurs->is_posdef) {
441           ierr = MatCholeskyFactorSymbolic(F,A,NULL,NULL);CHKERRQ(ierr);
442           ierr = MatCholeskyFactorNumeric(F,A,NULL);CHKERRQ(ierr);
443         } else {
444           ierr = MatLUFactorSymbolic(F,A,NULL,NULL,NULL);CHKERRQ(ierr);
445           ierr = MatLUFactorNumeric(F,A,NULL);CHKERRQ(ierr);
446         }
447 
448         /* get explicit Schur Complement computed during numeric factorization */
449         ierr = MatMumpsGetSchurComplement(F,&S_all);CHKERRQ(ierr);
450         ierr = MatDestroy(&F);CHKERRQ(ierr);
451       } else {
452         ierr = MatConvert(A,MATSEQDENSE,MAT_INITIAL_MATRIX,&S_all);CHKERRQ(ierr);
453       }
454       ierr = MatDestroy(&A);CHKERRQ(ierr);
455 #endif
456     }
457   } else {
458     ierr = PetscFree(nnz);CHKERRQ(ierr);
459   }
460 
461   if (!sub_schurs->n_subs_seq_g) { /* need to get rid of the old parallel deluxe */
462     ierr = PetscFree(all_local_idx_G);CHKERRQ(ierr);
463     ierr = PetscFree(all_local_idx_N);CHKERRQ(ierr);
464     ierr = PetscFree2(Bwork,pivots);CHKERRQ(ierr);
465     ierr = MatDestroy(&global_schur_subsets);CHKERRQ(ierr);
466     ierr = MatDestroy(&work_mat);CHKERRQ(ierr);
467     PetscFunctionReturn(0);
468   }
469 
470   /* subset indices in local boundary numbering */
471   if (!sub_schurs->is_Ej_all) {
472     PetscInt *all_local_idx_B;
473 
474     ierr = PetscMalloc1(local_size,&all_local_idx_B);CHKERRQ(ierr);
475     ierr = ISGlobalToLocalMappingApply(sub_schurs->BtoNmap,IS_GTOLM_DROP,local_size,all_local_idx_N+extra,&subset_size,all_local_idx_B);CHKERRQ(ierr);
476     if (subset_size != local_size) {
477       SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Error in sub_schurs serial (BtoNmap)! %d != %d\n",subset_size,local_size);
478     }
479     ierr = ISCreateGeneral(PETSC_COMM_SELF,local_size,all_local_idx_B,PETSC_OWN_POINTER,&sub_schurs->is_Ej_all);CHKERRQ(ierr);
480   }
481   ierr = PetscFree(all_local_idx_N);CHKERRQ(ierr);
482 
483   /* Local matrix of all local Schur on subsets (transposed) */
484   if (!sub_schurs->S_Ej_all) {
485     ierr = MatCreate(PETSC_COMM_SELF,&sub_schurs->S_Ej_all);CHKERRQ(ierr);
486     ierr = MatSetSizes(sub_schurs->S_Ej_all,PETSC_DECIDE,PETSC_DECIDE,local_size,local_size);CHKERRQ(ierr);
487     ierr = MatSetType(sub_schurs->S_Ej_all,MATAIJ);CHKERRQ(ierr);
488     ierr = MatSeqAIJSetPreallocation(sub_schurs->S_Ej_all,0,nnz);CHKERRQ(ierr);
489   } else {
490     ierr = MatZeroEntries(sub_schurs->S_Ej_all);CHKERRQ(ierr);
491   }
492 
493   ierr = PetscBTMemzero(sub_schurs->n_subs,sub_schurs->computed_Stilda_subs);CHKERRQ(ierr);
494   if (!sub_schurs->use_mumps) {
495     if (sub_schurs->n_subs_seq) {
496       PetscScalar *work;
497       PetscInt    *dummy_idx;
498 
499       /* Work arrays */
500       ierr = PetscMalloc2(max_subset_size_seq,&dummy_idx,max_subset_size_seq*max_subset_size_seq,&work);CHKERRQ(ierr);
501 
502       /* Loop on local problems end compute Schur complements explicitly */
503       local_size = 0;
504       for (i=0;i<sub_schurs->n_subs_seq;i++) {
505         Mat       S_Ej_expl;
506         PetscInt  j,lpi = sub_schurs->index_sequential[i];
507         PetscBool Sdense;
508 
509         ierr = ISGetLocalSize(sub_schurs->is_subs[lpi],&subset_size);CHKERRQ(ierr);
510         ierr = MatCreateSeqDense(PETSC_COMM_SELF,subset_size,subset_size,work,&S_Ej_expl);CHKERRQ(ierr);
511         ierr = PCBDDCComputeExplicitSchur(sub_schurs->S_Ej[lpi],sub_schurs->is_hermitian,MAT_REUSE_MATRIX,&S_Ej_expl);CHKERRQ(ierr);
512         ierr = PetscObjectTypeCompare((PetscObject)S_Ej_expl,MATSEQDENSE,&Sdense);CHKERRQ(ierr);
513         if (Sdense) {
514           for (j=0;j<subset_size;j++) {
515             dummy_idx[j]=local_size+j;
516           }
517           ierr = MatSetValues(sub_schurs->S_Ej_all,subset_size,dummy_idx,subset_size,dummy_idx,work,INSERT_VALUES);CHKERRQ(ierr);
518         } else {
519           SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Not yet implemented for sparse matrices");
520         }
521         local_size += subset_size;
522         ierr = MatDestroy(&sub_schurs->S_Ej[lpi]);CHKERRQ(ierr);
523         sub_schurs->S_Ej[lpi] = S_Ej_expl;
524       }
525       ierr = PetscFree2(dummy_idx,work);CHKERRQ(ierr);
526     }
527   } else {
528     PetscInt    *dummy_idx,n_all;
529     PetscScalar *work;
530 
531     if (compute_Stilda) {
532       ierr = MatCreate(PETSC_COMM_SELF,&S_Ej_tilda_all);CHKERRQ(ierr);
533       ierr = MatSetSizes(S_Ej_tilda_all,PETSC_DECIDE,PETSC_DECIDE,local_size,local_size);CHKERRQ(ierr);
534       ierr = MatSetType(S_Ej_tilda_all,MATAIJ);CHKERRQ(ierr);
535       ierr = MatSeqAIJSetPreallocation(S_Ej_tilda_all,0,nnz);CHKERRQ(ierr);
536       if (deluxe) {
537         ierr = MatCreate(PETSC_COMM_SELF,&S_Ej_inv_all);CHKERRQ(ierr);
538         ierr = MatSetSizes(S_Ej_inv_all,PETSC_DECIDE,PETSC_DECIDE,local_size,local_size);CHKERRQ(ierr);
539         ierr = MatSetType(S_Ej_inv_all,MATAIJ);CHKERRQ(ierr);
540         ierr = MatSeqAIJSetPreallocation(S_Ej_inv_all,0,nnz);CHKERRQ(ierr);
541       }
542     }
543 
544     if (S_all) { /* multilevel */
545       ierr = MatGetSize(S_all,&n_all,NULL);CHKERRQ(ierr);
546     } else {
547       n_all = 0;
548     }
549     local_size = 0;
550 
551     /* Work arrays */
552     if (compute_Stilda) {
553       ierr = PetscMalloc2(max_subset_size_seq,&dummy_idx,n_all*n_all,&work);CHKERRQ(ierr);
554     } else {
555       ierr = PetscMalloc2(max_subset_size_seq,&dummy_idx,0,&work);CHKERRQ(ierr);
556     }
557 
558     if (compute_Stilda && S_all) {
559       PetscScalar *vals;
560       ierr = PetscBLASIntCast(n_all,&B_N);CHKERRQ(ierr);
561       ierr = MatDuplicate(S_all,MAT_COPY_VALUES,&S_all_inv);CHKERRQ(ierr);
562       ierr = MatDenseGetArray(S_all_inv,&vals);CHKERRQ(ierr);
563       if (!sub_schurs->is_hermitian) {
564         PetscStackCallBLAS("LAPACKgetrf",LAPACKgetrf_(&B_N,&B_N,vals,&B_N,pivots,&B_ierr));
565         if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRF Lapack routine %d",(int)B_ierr);
566         PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,vals,&B_N,pivots,Bwork,&B_lwork,&B_ierr));
567         if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRI Lapack routine %d",(int)B_ierr);
568       } else {
569         PetscInt j,k;
570 
571         PetscStackCallBLAS("LAPACKpotrf",LAPACKpotrf_("L",&B_N,vals,&B_N,&B_ierr));
572         if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRF Lapack routine %d",(int)B_ierr);
573         PetscStackCallBLAS("LAPACKpotri",LAPACKpotri_("L",&B_N,vals,&B_N,&B_ierr));
574         if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRI Lapack routine %d",(int)B_ierr);
575         for (j=0;j<B_N;j++) {
576           for (k=j+1;k<B_N;k++) {
577             vals[k*B_N+j] = vals[j*B_N+k];
578           }
579         }
580       }
581       ierr = MatDenseRestoreArray(S_all_inv,&vals);CHKERRQ(ierr);
582     }
583 
584     for (i=0;i<sub_schurs->n_subs;i++) {
585       IS  is_E;
586       PetscScalar *vals;
587       PetscInt j;
588 
589       ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
590       for (j=0;j<subset_size;j++) {
591         dummy_idx[j]=local_size+j;
592       }
593       ierr = ISCreateStride(PetscObjectComm((PetscObject)sub_schurs->is_I),subset_size,local_size,1,&is_E);CHKERRQ(ierr);
594       if (sub_schurs->S_Ej[i]) {
595         ierr = MatGetSubMatrix(S_all,is_E,is_E,MAT_REUSE_MATRIX,&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
596       } else {
597         ierr = MatGetSubMatrix(S_all,is_E,is_E,MAT_INITIAL_MATRIX,&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
598       }
599       ierr = MatDenseGetArray(sub_schurs->S_Ej[i],&vals);CHKERRQ(ierr);
600       ierr = MatSetValues(sub_schurs->S_Ej_all,subset_size,dummy_idx,subset_size,dummy_idx,vals,INSERT_VALUES);CHKERRQ(ierr);
601       ierr = MatDenseRestoreArray(sub_schurs->S_Ej[i],&vals);CHKERRQ(ierr);
602 
603       if (compute_Stilda && ((PetscBTLookup(sub_schurs->is_edge,i) && use_edges) || (!PetscBTLookup(sub_schurs->is_edge,i) && use_faces))) {
604         Mat Stilda;
605 
606         ierr = PetscBTSet(sub_schurs->computed_Stilda_subs,i);CHKERRQ(ierr);
607         ierr = MatGetSubMatrix(S_all_inv,is_E,is_E,MAT_INITIAL_MATRIX,&Stilda);CHKERRQ(ierr);
608         ierr = MatDenseGetArray(Stilda,&vals);CHKERRQ(ierr);
609         if (deluxe) { /* when using deluxe scaling, we need (S_1^-1+S_2^-1)^-1 */
610           PetscScalar *vals2;
611 
612           ierr = PetscBLASIntCast(subset_size,&B_N);CHKERRQ(ierr);
613           ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
614           ierr = MatDenseGetArray(sub_schurs->S_Ej[i],&vals2);CHKERRQ(ierr);
615           if (!sub_schurs->is_hermitian) {
616             PetscStackCallBLAS("LAPACKgetrf",LAPACKgetrf_(&B_N,&B_N,vals2,&B_N,pivots,&B_ierr));
617             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRF Lapack routine %d",(int)B_ierr);
618             PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,vals2,&B_N,pivots,Bwork,&B_lwork,&B_ierr));
619             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRI Lapack routine %d",(int)B_ierr);
620           } else {
621             PetscInt j,k;
622 
623             PetscStackCallBLAS("LAPACKpotrf",LAPACKpotrf_("L",&B_N,vals2,&B_N,&B_ierr));
624             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRF Lapack routine %d",(int)B_ierr);
625             PetscStackCallBLAS("LAPACKpotri",LAPACKpotri_("L",&B_N,vals2,&B_N,&B_ierr));
626             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRI Lapack routine %d",(int)B_ierr);
627             for (j=0;j<B_N;j++) {
628               for (k=j+1;k<B_N;k++) {
629                 vals2[k*B_N+j] = vals2[j*B_N+k];
630               }
631             }
632           }
633           ierr = PetscFPTrapPop();CHKERRQ(ierr);
634           ierr = MatSetValues(S_Ej_inv_all,subset_size,dummy_idx,subset_size,dummy_idx,vals2,INSERT_VALUES);CHKERRQ(ierr);
635           ierr = MatDenseRestoreArray(sub_schurs->S_Ej[i],&vals2);CHKERRQ(ierr);
636         }
637         ierr = MatSetValues(S_Ej_tilda_all,subset_size,dummy_idx,subset_size,dummy_idx,vals,INSERT_VALUES);CHKERRQ(ierr);
638         ierr = MatDenseRestoreArray(Stilda,&vals);CHKERRQ(ierr);
639         ierr = MatDestroy(&Stilda);CHKERRQ(ierr);
640       }
641       ierr = ISDestroy(&is_E);CHKERRQ(ierr);
642       local_size += subset_size;
643     }
644     ierr = PetscFree2(dummy_idx,work);CHKERRQ(ierr);
645   }
646   ierr = PetscFree(nnz);CHKERRQ(ierr);
647   ierr = MatDestroy(&S_all);CHKERRQ(ierr);
648   ierr = MatDestroy(&S_all_inv);CHKERRQ(ierr);
649   ierr = MatAssemblyBegin(sub_schurs->S_Ej_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
650   ierr = MatAssemblyEnd(sub_schurs->S_Ej_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
651   if (S_Ej_tilda_all) {
652     ierr = MatAssemblyBegin(S_Ej_tilda_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
653     ierr = MatAssemblyEnd(S_Ej_tilda_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
654   }
655   if (S_Ej_inv_all) {
656     ierr = MatAssemblyBegin(S_Ej_inv_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
657     ierr = MatAssemblyEnd(S_Ej_inv_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
658   }
659 
660   /* Global matrix of all assembled Schur on subsets */
661   ierr = MatISSetLocalMat(work_mat,sub_schurs->S_Ej_all);CHKERRQ(ierr);
662   ierr = MatISSetMPIXAIJPreallocation_Private(work_mat,global_schur_subsets,PETSC_TRUE);CHKERRQ(ierr);
663   ierr = MatISGetMPIXAIJ(work_mat,MAT_REUSE_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
664   /* Get local part of (\sum_j S_Ej) */
665   ierr = ISCreateGeneral(PetscObjectComm((PetscObject)sub_schurs->l2gmap),local_size,all_local_idx_G,PETSC_OWN_POINTER,&temp_is);CHKERRQ(ierr);
666   ierr = MatDestroy(&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
667   ierr = MatGetSubMatrixUnsorted(global_schur_subsets,temp_is,temp_is,&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
668 
669   if (S_Ej_tilda_all) {
670     ierr = MatISSetLocalMat(work_mat,S_Ej_tilda_all);CHKERRQ(ierr);
671     ierr = MatISGetMPIXAIJ(work_mat,MAT_REUSE_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
672     ierr = MatDestroy(&sub_schurs->sum_S_Ej_tilda_all);CHKERRQ(ierr);
673     ierr = MatGetSubMatrixUnsorted(global_schur_subsets,temp_is,temp_is,&sub_schurs->sum_S_Ej_tilda_all);CHKERRQ(ierr);
674   }
675   if (S_Ej_inv_all) {
676     PetscInt    cum;
677     PetscScalar *array,*array2;
678     ierr = MatISSetLocalMat(work_mat,S_Ej_inv_all);CHKERRQ(ierr);
679     ierr = MatISGetMPIXAIJ(work_mat,MAT_REUSE_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
680     ierr = MatDestroy(&sub_schurs->sum_S_Ej_inv_all);CHKERRQ(ierr);
681     ierr = MatGetSubMatrixUnsorted(global_schur_subsets,temp_is,temp_is,&sub_schurs->sum_S_Ej_inv_all);CHKERRQ(ierr);
682     /* invert blocks of sum_S_Ej_inv_all */
683     ierr = MatSeqAIJGetArray(sub_schurs->sum_S_Ej_inv_all,&array);CHKERRQ(ierr);
684     ierr = MatSeqAIJGetArray(sub_schurs->sum_S_Ej_tilda_all,&array2);CHKERRQ(ierr);
685     cum = 0;
686     for (i=0;i<sub_schurs->n_subs;i++) {
687       ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
688       if (PetscBTLookup(sub_schurs->computed_Stilda_subs,i)) {
689         ierr = PetscBLASIntCast(subset_size,&B_N);CHKERRQ(ierr);
690         ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
691         if (!sub_schurs->is_hermitian) {
692           PetscStackCallBLAS("LAPACKgetrf",LAPACKgetrf_(&B_N,&B_N,array+cum,&B_N,pivots,&B_ierr));
693           if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRF Lapack routine %d",(int)B_ierr);
694           PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,array+cum,&B_N,pivots,Bwork,&B_lwork,&B_ierr));
695           if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRI Lapack routine %d",(int)B_ierr);
696         } else {
697           PetscInt j,k;
698 
699           PetscStackCallBLAS("LAPACKpotrf",LAPACKpotrf_("L",&B_N,array+cum,&B_N,&B_ierr));
700           if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRF Lapack routine %d",(int)B_ierr);
701           PetscStackCallBLAS("LAPACKpotri",LAPACKpotri_("L",&B_N,array+cum,&B_N,&B_ierr));
702           if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRI Lapack routine %d",(int)B_ierr);
703           for (j=0;j<B_N;j++) {
704             for (k=j+1;k<B_N;k++) {
705               array[k*B_N+j+cum] = array[j*B_N+k+cum];
706             }
707           }
708         }
709         if (invert_Stildas) { /* Stildas can be singular */
710           if (!sub_schurs->is_hermitian) {
711             PetscStackCallBLAS("LAPACKgetrf",LAPACKgetrf_(&B_N,&B_N,array2+cum,&B_N,pivots,&B_ierr));
712             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRF Lapack routine %d",(int)B_ierr);
713             PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,array2+cum,&B_N,pivots,Bwork,&B_lwork,&B_ierr));
714             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRI Lapack routine %d",(int)B_ierr);
715           } else {
716             PetscInt j,k;
717 
718             PetscStackCallBLAS("LAPACKpotrf",LAPACKpotrf_("L",&B_N,array2+cum,&B_N,&B_ierr));
719             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRF Lapack routine %d",(int)B_ierr);
720             PetscStackCallBLAS("LAPACKpotri",LAPACKpotri_("L",&B_N,array2+cum,&B_N,&B_ierr));
721             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRI Lapack routine %d",(int)B_ierr);
722             for (j=0;j<B_N;j++) {
723               for (k=j+1;k<B_N;k++) {
724                 array2[k*B_N+j+cum] = array2[j*B_N+k+cum];
725               }
726             }
727           }
728         }
729         ierr = PetscFPTrapPop();CHKERRQ(ierr);
730       }
731       cum += subset_size*subset_size;
732     }
733     ierr = MatSeqAIJRestoreArray(sub_schurs->sum_S_Ej_inv_all,&array);CHKERRQ(ierr);
734     ierr = MatSeqAIJRestoreArray(sub_schurs->sum_S_Ej_tilda_all,&array2);CHKERRQ(ierr);
735   }
736 
737   ierr = PetscFree2(Bwork,pivots);CHKERRQ(ierr);
738   ierr = MatDestroy(&global_schur_subsets);CHKERRQ(ierr);
739   ierr = MatDestroy(&S_Ej_tilda_all);CHKERRQ(ierr);
740   ierr = MatDestroy(&S_Ej_inv_all);CHKERRQ(ierr);
741   ierr = MatDestroy(&work_mat);CHKERRQ(ierr);
742   ierr = ISDestroy(&temp_is);CHKERRQ(ierr);
743   PetscFunctionReturn(0);
744 }
745 
746 #undef __FUNCT__
747 #define __FUNCT__ "PCBDDCSubSchursInit"
748 PetscErrorCode PCBDDCSubSchursInit(PCBDDCSubSchurs sub_schurs, Mat A, Mat S, IS is_I, IS is_B, PCBDDCGraph graph, ISLocalToGlobalMapping BtoNmap, PetscInt seqthreshold)
749 {
750   IS                  *faces,*edges,*all_cc,vertices;
751   PetscInt            *index_sequential,*index_parallel;
752   PetscInt            *auxlocal_sequential,*auxlocal_parallel;
753   PetscInt            *auxglobal_sequential,*auxglobal_parallel;
754   PetscInt            *auxmapping;
755   PetscInt            i,max_subset_size;
756   PetscInt            n_sequential_problems,n_local_sequential_problems,n_parallel_problems,n_local_parallel_problems;
757   PetscInt            n_faces,n_edges,n_all_cc;
758   PetscBool           is_sorted;
759   PetscErrorCode  ierr;
760 
761   PetscFunctionBegin;
762   ierr = ISSorted(is_I,&is_sorted);CHKERRQ(ierr);
763   if (!is_sorted) {
764     SETERRQ(PetscObjectComm((PetscObject)is_I),PETSC_ERR_PLIB,"IS for I dofs should be shorted");
765   }
766   ierr = ISSorted(is_B,&is_sorted);CHKERRQ(ierr);
767   if (!is_sorted) {
768     SETERRQ(PetscObjectComm((PetscObject)is_B),PETSC_ERR_PLIB,"IS for B dofs should be shorted");
769   }
770 
771   /* reset any previous data */
772   ierr = PCBDDCSubSchursReset(sub_schurs);CHKERRQ(ierr);
773 
774   /* get index sets for faces and edges */
775   ierr = PCBDDCGraphGetCandidatesIS(graph,&n_faces,&faces,&n_edges,&edges,&vertices);CHKERRQ(ierr);
776   n_all_cc = n_faces+n_edges;
777   ierr = PetscBTCreate(n_all_cc,&sub_schurs->is_edge);CHKERRQ(ierr);
778   ierr = PetscBTCreate(n_all_cc,&sub_schurs->computed_Stilda_subs);CHKERRQ(ierr);
779   ierr = PetscMalloc1(n_all_cc,&all_cc);CHKERRQ(ierr);
780   for (i=0;i<n_faces;i++) {
781     all_cc[i] = faces[i];
782   }
783   for (i=0;i<n_edges;i++) {
784     all_cc[n_faces+i] = edges[i];
785     ierr = PetscBTSet(sub_schurs->is_edge,n_faces+i);CHKERRQ(ierr);
786   }
787   ierr = PetscFree(faces);CHKERRQ(ierr);
788   ierr = PetscFree(edges);CHKERRQ(ierr);
789 
790   /* map interface's subsets */
791   max_subset_size = 0;
792   for (i=0;i<n_all_cc;i++) {
793     PetscInt subset_size;
794     ierr = ISGetLocalSize(all_cc[i],&subset_size);CHKERRQ(ierr);
795     max_subset_size = PetscMax(max_subset_size,subset_size);
796   }
797   ierr = PetscMalloc1(max_subset_size,&auxmapping);CHKERRQ(ierr);
798   ierr = PetscMalloc2(graph->ncc,&auxlocal_sequential,
799                       graph->ncc,&auxlocal_parallel);CHKERRQ(ierr);
800   ierr = PetscMalloc2(graph->ncc,&index_sequential,
801                       graph->ncc,&index_parallel);CHKERRQ(ierr);
802 
803   /* if threshold is negative uses all sequential problems (possibly using MUMPS) */
804   sub_schurs->use_mumps = PETSC_FALSE;
805   if (seqthreshold < 0) {
806     seqthreshold = max_subset_size;
807 #if defined(PETSC_HAVE_MUMPS)
808     sub_schurs->use_mumps = (PetscBool)(!!A);
809 #endif
810   }
811 
812 
813   /* determine which problem has to be solved in parallel or sequentially */
814   n_local_sequential_problems = 0;
815   n_local_parallel_problems = 0;
816   for (i=0;i<n_all_cc;i++) {
817     PetscInt       subset_size,j,min_loc = 0;
818     const PetscInt *idxs;
819 
820     ierr = ISGetLocalSize(all_cc[i],&subset_size);CHKERRQ(ierr);
821     ierr = ISGetIndices(all_cc[i],&idxs);CHKERRQ(ierr);
822     ierr = ISLocalToGlobalMappingApply(graph->l2gmap,subset_size,idxs,auxmapping);CHKERRQ(ierr);
823     for (j=1;j<subset_size;j++) {
824       if (auxmapping[j]<auxmapping[min_loc]) {
825         min_loc = j;
826       }
827     }
828     if (subset_size > seqthreshold) {
829       index_parallel[n_local_parallel_problems] = i;
830       auxlocal_parallel[n_local_parallel_problems] = idxs[min_loc];
831       n_local_parallel_problems++;
832     } else {
833       index_sequential[n_local_sequential_problems] = i;
834       auxlocal_sequential[n_local_sequential_problems] = idxs[min_loc];
835       n_local_sequential_problems++;
836     }
837     ierr = ISRestoreIndices(all_cc[i],&idxs);CHKERRQ(ierr);
838   }
839 
840   /* Number parallel problems */
841   auxglobal_parallel = 0;
842   ierr = PCBDDCSubsetNumbering(PetscObjectComm((PetscObject)graph->l2gmap),graph->l2gmap,n_local_parallel_problems,auxlocal_parallel,PETSC_NULL,&n_parallel_problems,&auxglobal_parallel);CHKERRQ(ierr);
843 
844   /* Number sequential problems */
845   auxglobal_sequential = 0;
846   ierr = PCBDDCSubsetNumbering(PetscObjectComm((PetscObject)graph->l2gmap),graph->l2gmap,n_local_sequential_problems,auxlocal_sequential,PETSC_NULL,&n_sequential_problems,&auxglobal_sequential);CHKERRQ(ierr);
847 
848   /* update info in sub_schurs */
849   if (A) {
850     PetscBool isseqaij;
851 
852     ierr = PetscObjectTypeCompare((PetscObject)A,MATSEQAIJ,&isseqaij);CHKERRQ(ierr);
853     if (isseqaij) {
854       ierr = PetscObjectReference((PetscObject)A);CHKERRQ(ierr);
855       sub_schurs->A = A;
856     } else { /* SeqBAIJ matrices does not support symmetry checking, SeqSBAIJ does not support MatPermute */
857       ierr = MatConvert(A,MATSEQAIJ,MAT_INITIAL_MATRIX,&sub_schurs->A);CHKERRQ(ierr);
858     }
859   }
860   ierr = PetscObjectReference((PetscObject)S);CHKERRQ(ierr);
861   sub_schurs->S = S;
862   ierr = PetscObjectReference((PetscObject)is_I);CHKERRQ(ierr);
863   sub_schurs->is_I = is_I;
864   ierr = PetscObjectReference((PetscObject)is_B);CHKERRQ(ierr);
865   sub_schurs->is_B = is_B;
866   ierr = PetscObjectReference((PetscObject)graph->l2gmap);CHKERRQ(ierr);
867   sub_schurs->l2gmap = graph->l2gmap;
868   ierr = PetscObjectReference((PetscObject)BtoNmap);CHKERRQ(ierr);
869   sub_schurs->BtoNmap = BtoNmap;
870   sub_schurs->n_subs_seq = n_local_sequential_problems;
871   sub_schurs->n_subs_par = n_local_parallel_problems;
872   sub_schurs->n_subs_seq_g = n_sequential_problems;
873   sub_schurs->n_subs_par_g = n_parallel_problems;
874   sub_schurs->n_subs = sub_schurs->n_subs_seq + sub_schurs->n_subs_par;
875   sub_schurs->is_subs = all_cc;
876   if (!sub_schurs->use_mumps) { /* for adaptive selection */
877     for (i=0;i<sub_schurs->n_subs;i++) {
878       ierr = ISSort(sub_schurs->is_subs[i]);CHKERRQ(ierr);
879     }
880   }
881   sub_schurs->is_Ej_com = vertices;
882   sub_schurs->index_sequential = index_sequential;
883   sub_schurs->index_parallel = index_parallel;
884   sub_schurs->auxglobal_sequential = auxglobal_sequential;
885   sub_schurs->auxglobal_parallel = auxglobal_parallel;
886 
887 
888   /* allocate space for schur complements */
889   ierr = PetscCalloc1(sub_schurs->n_subs,&sub_schurs->S_Ej);CHKERRQ(ierr);
890   sub_schurs->S_Ej_all = NULL;
891   sub_schurs->sum_S_Ej_all = NULL;
892   sub_schurs->sum_S_Ej_inv_all = NULL;
893   sub_schurs->sum_S_Ej_tilda_all = NULL;
894   sub_schurs->is_Ej_all = NULL;
895 
896   /* free workspace */
897   ierr = PetscFree(auxmapping);CHKERRQ(ierr);
898   ierr = PetscFree2(auxlocal_sequential,auxlocal_parallel);CHKERRQ(ierr);
899 
900   PetscFunctionReturn(0);
901 }
902 
903 #undef __FUNCT__
904 #define __FUNCT__ "PCBDDCSubSchursCreate"
905 PetscErrorCode PCBDDCSubSchursCreate(PCBDDCSubSchurs *sub_schurs)
906 {
907   PCBDDCSubSchurs schurs_ctx;
908   PetscErrorCode  ierr;
909 
910   PetscFunctionBegin;
911   ierr = PetscNew(&schurs_ctx);CHKERRQ(ierr);
912   schurs_ctx->n_subs = 0;
913   *sub_schurs = schurs_ctx;
914   PetscFunctionReturn(0);
915 }
916 
917 #undef __FUNCT__
918 #define __FUNCT__ "PCBDDCSubSchursDestroy"
919 PetscErrorCode PCBDDCSubSchursDestroy(PCBDDCSubSchurs *sub_schurs)
920 {
921   PetscErrorCode ierr;
922 
923   PetscFunctionBegin;
924   ierr = PCBDDCSubSchursReset(*sub_schurs);CHKERRQ(ierr);
925   ierr = PetscFree(*sub_schurs);CHKERRQ(ierr);
926   PetscFunctionReturn(0);
927 }
928 
929 #undef __FUNCT__
930 #define __FUNCT__ "PCBDDCSubSchursReset"
931 PetscErrorCode PCBDDCSubSchursReset(PCBDDCSubSchurs sub_schurs)
932 {
933   PetscInt       i;
934   PetscErrorCode ierr;
935 
936   PetscFunctionBegin;
937   ierr = MatDestroy(&sub_schurs->A);CHKERRQ(ierr);
938   ierr = MatDestroy(&sub_schurs->S);CHKERRQ(ierr);
939   ierr = ISDestroy(&sub_schurs->is_I);CHKERRQ(ierr);
940   ierr = ISDestroy(&sub_schurs->is_B);CHKERRQ(ierr);
941   ierr = ISLocalToGlobalMappingDestroy(&sub_schurs->l2gmap);CHKERRQ(ierr);
942   ierr = ISLocalToGlobalMappingDestroy(&sub_schurs->BtoNmap);CHKERRQ(ierr);
943   ierr = MatDestroy(&sub_schurs->S_Ej_all);CHKERRQ(ierr);
944   ierr = MatDestroy(&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
945   ierr = MatDestroy(&sub_schurs->sum_S_Ej_inv_all);CHKERRQ(ierr);
946   ierr = MatDestroy(&sub_schurs->sum_S_Ej_tilda_all);CHKERRQ(ierr);
947   ierr = ISDestroy(&sub_schurs->is_Ej_all);CHKERRQ(ierr);
948   ierr = ISDestroy(&sub_schurs->is_Ej_com);CHKERRQ(ierr);
949   ierr = PetscBTDestroy(&sub_schurs->is_edge);CHKERRQ(ierr);
950   ierr = PetscBTDestroy(&sub_schurs->computed_Stilda_subs);CHKERRQ(ierr);
951   for (i=0;i<sub_schurs->n_subs;i++) {
952     ierr = ISDestroy(&sub_schurs->is_subs[i]);CHKERRQ(ierr);
953     ierr = MatDestroy(&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
954   }
955   ierr = ISDestroy(&sub_schurs->is_I_layer);CHKERRQ(ierr);
956   if (sub_schurs->n_subs) {
957     ierr = PetscFree(sub_schurs->is_subs);CHKERRQ(ierr);
958     ierr = PetscFree(sub_schurs->S_Ej);CHKERRQ(ierr);
959   }
960   ierr = PetscFree2(sub_schurs->index_sequential,sub_schurs->index_parallel);CHKERRQ(ierr);
961   ierr = PetscFree(sub_schurs->auxglobal_sequential);CHKERRQ(ierr);
962   ierr = PetscFree(sub_schurs->auxglobal_parallel);CHKERRQ(ierr);
963   sub_schurs->n_subs = 0;
964   PetscFunctionReturn(0);
965 }
966 
967 #undef __FUNCT__
968 #define __FUNCT__ "PCBDDCAdjGetNextLayer_Private"
969 PETSC_STATIC_INLINE PetscErrorCode PCBDDCAdjGetNextLayer_Private(PetscInt* queue_tip,PetscInt n_prev,PetscBT touched,PetscInt* xadj,PetscInt* adjncy,PetscInt* n_added)
970 {
971   PetscInt       i,j,n;
972   PetscErrorCode ierr;
973 
974   PetscFunctionBegin;
975   n = 0;
976   for (i=-n_prev;i<0;i++) {
977     PetscInt start_dof = queue_tip[i];
978     for (j=xadj[start_dof];j<xadj[start_dof+1];j++) {
979       PetscInt dof = adjncy[j];
980       if (!PetscBTLookup(touched,dof)) {
981         ierr = PetscBTSet(touched,dof);CHKERRQ(ierr);
982         queue_tip[n] = dof;
983         n++;
984       }
985     }
986   }
987   *n_added = n;
988   PetscFunctionReturn(0);
989 }
990