xref: /petsc/src/ksp/pc/impls/bddc/bddcschurs.c (revision 4f2d7caf62749777129f8e1f39d8a03cd073aa5c)
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 static PetscErrorCode PCBDDCReuseSolvers_Interior(PC,Vec,Vec);
8 static PetscErrorCode PCBDDCReuseSolvers_Correction(PC,Vec,Vec);
9 
10 /* if v2 is not present, correction is done in-place */
11 #undef __FUNCT__
12 #define __FUNCT__ "PCBDDCReuseSolversBenignAdapt"
13 PetscErrorCode PCBDDCReuseSolversBenignAdapt(PCBDDCReuseSolvers ctx, Vec v, Vec v2, PetscBool sol, PetscBool full)
14 {
15   PetscScalar    *array;
16   PetscScalar    *array2;
17   PetscErrorCode ierr;
18 
19   PetscFunctionBegin;
20   if (!ctx->benign_n) PetscFunctionReturn(0);
21   if (sol && full) {
22     PetscInt n_I,size_schur;
23 
24     /* get sizes */
25     ierr = MatGetSize(ctx->benign_csAIB,NULL,&size_schur);CHKERRQ(ierr);
26     ierr = VecGetSize(v,&n_I);CHKERRQ(ierr);
27     n_I = n_I - size_schur;
28     /* get schur sol from array */
29     ierr = VecGetArray(v,&array);CHKERRQ(ierr);
30     ierr = VecPlaceArray(ctx->benign_dummy_schur_vec,array+n_I);CHKERRQ(ierr);
31     ierr = VecRestoreArray(v,&array);CHKERRQ(ierr);
32     /* apply interior sol correction */
33     ierr = MatMult(ctx->benign_csAIB,ctx->benign_dummy_schur_vec,ctx->benign_corr_work);CHKERRQ(ierr);
34     ierr = VecResetArray(ctx->benign_dummy_schur_vec);CHKERRQ(ierr);
35     ierr = MatMultAdd(ctx->benign_AIIm1ones,ctx->benign_corr_work,v,v);CHKERRQ(ierr);
36   }
37   if (v2) {
38     PetscInt nl;
39 
40     ierr = VecGetArrayRead(v,(const PetscScalar**)&array);CHKERRQ(ierr);
41     ierr = VecGetLocalSize(v2,&nl);CHKERRQ(ierr);
42     ierr = VecGetArray(v2,&array2);CHKERRQ(ierr);
43     ierr = PetscMemcpy(array2,array,nl*sizeof(PetscScalar));CHKERRQ(ierr);
44   } else {
45     ierr = VecGetArray(v,&array);CHKERRQ(ierr);
46     array2 = array;
47   }
48   if (!sol) { /* change rhs */
49     PetscInt n;
50     for (n=0;n<ctx->benign_n;n++) {
51       PetscScalar    sum = 0.;
52       const PetscInt *cols;
53       PetscInt       nz,i;
54 
55       ierr = ISGetLocalSize(ctx->benign_zerodiag_subs[n],&nz);CHKERRQ(ierr);
56       ierr = ISGetIndices(ctx->benign_zerodiag_subs[n],&cols);CHKERRQ(ierr);
57       for (i=0;i<nz-1;i++) sum += array[cols[i]];
58       sum = -sum/nz;
59       for (i=0;i<nz-1;i++) array2[cols[i]] += sum;
60       ctx->benign_save_vals[n] = array2[cols[nz-1]];
61       array2[cols[nz-1]] = sum;
62       ierr = ISRestoreIndices(ctx->benign_zerodiag_subs[n],&cols);CHKERRQ(ierr);
63     }
64   } else {
65     PetscInt n;
66     for (n=0;n<ctx->benign_n;n++) {
67       PetscScalar    sum = 0.;
68       const PetscInt *cols;
69       PetscInt       nz,i;
70       ierr = ISGetLocalSize(ctx->benign_zerodiag_subs[n],&nz);CHKERRQ(ierr);
71       ierr = ISGetIndices(ctx->benign_zerodiag_subs[n],&cols);CHKERRQ(ierr);
72       for (i=0;i<nz-1;i++) sum += array[cols[i]];
73       sum = -sum/nz;
74       for (i=0;i<nz-1;i++) array2[cols[i]] += sum;
75       array2[cols[nz-1]] = ctx->benign_save_vals[n];
76       ierr = ISRestoreIndices(ctx->benign_zerodiag_subs[n],&cols);CHKERRQ(ierr);
77     }
78   }
79   if (v2) {
80     ierr = VecRestoreArrayRead(v,(const PetscScalar**)&array);CHKERRQ(ierr);
81     ierr = VecRestoreArray(v2,&array2);CHKERRQ(ierr);
82   } else {
83     ierr = VecRestoreArray(v,&array);CHKERRQ(ierr);
84   }
85   if (!sol && full) {
86     Vec      usedv;
87     PetscInt n_I,size_schur;
88 
89     /* get sizes */
90     ierr = MatGetSize(ctx->benign_csAIB,NULL,&size_schur);CHKERRQ(ierr);
91     ierr = VecGetSize(v,&n_I);CHKERRQ(ierr);
92     n_I = n_I - size_schur;
93     /* compute schur rhs correction */
94     if (v2) {
95       usedv = v2;
96     } else {
97       usedv = v;
98     }
99     /* apply schur rhs correction */
100     ierr = MatMultTranspose(ctx->benign_AIIm1ones,usedv,ctx->benign_corr_work);CHKERRQ(ierr);
101     ierr = VecGetArrayRead(usedv,(const PetscScalar**)&array);CHKERRQ(ierr);
102     ierr = VecPlaceArray(ctx->benign_dummy_schur_vec,array+n_I);CHKERRQ(ierr);
103     ierr = VecRestoreArrayRead(usedv,(const PetscScalar**)&array);CHKERRQ(ierr);
104     ierr = MatMultTransposeAdd(ctx->benign_csAIB,ctx->benign_corr_work,ctx->benign_dummy_schur_vec,ctx->benign_dummy_schur_vec);CHKERRQ(ierr);
105     ierr = VecResetArray(ctx->benign_dummy_schur_vec);CHKERRQ(ierr);
106   }
107   PetscFunctionReturn(0);
108 }
109 
110 #undef __FUNCT__
111 #define __FUNCT__ "PCBDDCReuseSolvers_Solve_Private"
112 static PetscErrorCode PCBDDCReuseSolvers_Solve_Private(PC pc, Vec rhs, Vec sol, PetscBool transpose, PetscBool full)
113 {
114   PCBDDCReuseSolvers ctx;
115   PetscBool          copy = PETSC_FALSE;
116   PetscErrorCode     ierr;
117 
118   PetscFunctionBegin;
119   ierr = PCShellGetContext(pc,(void **)&ctx);CHKERRQ(ierr);
120   if (full) {
121 #if defined(PETSC_HAVE_MUMPS)
122     ierr = MatMumpsSetIcntl(ctx->F,26,-1);CHKERRQ(ierr);
123 #endif
124 #if defined(PETSC_HAVE_MKL_PARDISO)
125     ierr = MatMkl_PardisoSetCntl(ctx->F,70,0);CHKERRQ(ierr);
126 #endif
127     copy = ctx->has_vertices;
128   } else { /* interior solver */
129 #if defined(PETSC_HAVE_MUMPS)
130     ierr = MatMumpsSetIcntl(ctx->F,26,0);CHKERRQ(ierr);
131 #endif
132 #if defined(PETSC_HAVE_MKL_PARDISO)
133     ierr = MatMkl_PardisoSetCntl(ctx->F,70,1);CHKERRQ(ierr);
134 #endif
135     copy = PETSC_TRUE;
136   }
137   /* copy rhs into factored matrix workspace */
138   if (copy) {
139     PetscInt    n;
140     PetscScalar *array,*array_solver;
141 
142     ierr = VecGetLocalSize(rhs,&n);CHKERRQ(ierr);
143     ierr = VecGetArrayRead(rhs,(const PetscScalar**)&array);CHKERRQ(ierr);
144     ierr = VecGetArray(ctx->rhs,&array_solver);CHKERRQ(ierr);
145     ierr = PetscMemcpy(array_solver,array,n*sizeof(PetscScalar));CHKERRQ(ierr);
146     ierr = VecRestoreArray(ctx->rhs,&array_solver);CHKERRQ(ierr);
147     ierr = VecRestoreArrayRead(rhs,(const PetscScalar**)&array);CHKERRQ(ierr);
148 
149     ierr = PCBDDCReuseSolversBenignAdapt(ctx,ctx->rhs,NULL,PETSC_FALSE,full);CHKERRQ(ierr);
150     if (transpose) {
151       ierr = MatSolveTranspose(ctx->F,ctx->rhs,ctx->sol);CHKERRQ(ierr);
152     } else {
153       ierr = MatSolve(ctx->F,ctx->rhs,ctx->sol);CHKERRQ(ierr);
154     }
155     ierr = PCBDDCReuseSolversBenignAdapt(ctx,ctx->sol,NULL,PETSC_TRUE,full);CHKERRQ(ierr);
156 
157     /* get back data to caller worskpace */
158     ierr = VecGetArrayRead(ctx->sol,(const PetscScalar**)&array_solver);CHKERRQ(ierr);
159     ierr = VecGetArray(sol,&array);CHKERRQ(ierr);
160     ierr = PetscMemcpy(array,array_solver,n*sizeof(PetscScalar));CHKERRQ(ierr);
161     ierr = VecRestoreArray(sol,&array);CHKERRQ(ierr);
162     ierr = VecRestoreArrayRead(ctx->sol,(const PetscScalar**)&array_solver);CHKERRQ(ierr);
163   } else {
164     if (ctx->benign_n) {
165       ierr = PCBDDCReuseSolversBenignAdapt(ctx,rhs,ctx->rhs,PETSC_FALSE,full);CHKERRQ(ierr);
166       if (transpose) {
167         ierr = MatSolveTranspose(ctx->F,ctx->rhs,sol);CHKERRQ(ierr);
168       } else {
169         ierr = MatSolve(ctx->F,ctx->rhs,sol);CHKERRQ(ierr);
170       }
171       ierr = PCBDDCReuseSolversBenignAdapt(ctx,sol,NULL,PETSC_TRUE,full);CHKERRQ(ierr);
172     } else {
173       if (transpose) {
174         ierr = MatSolveTranspose(ctx->F,rhs,sol);CHKERRQ(ierr);
175       } else {
176         ierr = MatSolve(ctx->F,rhs,sol);CHKERRQ(ierr);
177       }
178     }
179   }
180   /* restore defaults */
181 #if defined(PETSC_HAVE_MUMPS)
182   ierr = MatMumpsSetIcntl(ctx->F,26,-1);CHKERRQ(ierr);
183 #endif
184 #if defined(PETSC_HAVE_MKL_PARDISO)
185   ierr = MatMkl_PardisoSetCntl(ctx->F,70,0);CHKERRQ(ierr);
186 #endif
187   PetscFunctionReturn(0);
188 }
189 
190 #undef __FUNCT__
191 #define __FUNCT__ "PCBDDCReuseSolvers_Correction"
192 static PetscErrorCode PCBDDCReuseSolvers_Correction(PC pc, Vec rhs, Vec sol)
193 {
194   PetscErrorCode   ierr;
195 
196   PetscFunctionBegin;
197   ierr = PCBDDCReuseSolvers_Solve_Private(pc,rhs,sol,PETSC_FALSE,PETSC_TRUE);CHKERRQ(ierr);
198   PetscFunctionReturn(0);
199 }
200 
201 #undef __FUNCT__
202 #define __FUNCT__ "PCBDDCReuseSolvers_CorrectionTranspose"
203 static PetscErrorCode PCBDDCReuseSolvers_CorrectionTranspose(PC pc, Vec rhs, Vec sol)
204 {
205   PetscErrorCode   ierr;
206 
207   PetscFunctionBegin;
208   ierr = PCBDDCReuseSolvers_Solve_Private(pc,rhs,sol,PETSC_TRUE,PETSC_TRUE);CHKERRQ(ierr);
209   PetscFunctionReturn(0);
210 }
211 
212 #undef __FUNCT__
213 #define __FUNCT__ "PCBDDCReuseSolvers_Interior"
214 static PetscErrorCode PCBDDCReuseSolvers_Interior(PC pc, Vec rhs, Vec sol)
215 {
216   PetscErrorCode   ierr;
217 
218   PetscFunctionBegin;
219   ierr = PCBDDCReuseSolvers_Solve_Private(pc,rhs,sol,PETSC_FALSE,PETSC_FALSE);CHKERRQ(ierr);
220   PetscFunctionReturn(0);
221 }
222 
223 #undef __FUNCT__
224 #define __FUNCT__ "PCBDDCReuseSolvers_InteriorTranspose"
225 static PetscErrorCode PCBDDCReuseSolvers_InteriorTranspose(PC pc, Vec rhs, Vec sol)
226 {
227   PetscErrorCode   ierr;
228 
229   PetscFunctionBegin;
230   ierr = PCBDDCReuseSolvers_Solve_Private(pc,rhs,sol,PETSC_TRUE,PETSC_FALSE);CHKERRQ(ierr);
231   PetscFunctionReturn(0);
232 }
233 
234 #undef __FUNCT__
235 #define __FUNCT__ "PCBDDCReuseSolversReset"
236 static PetscErrorCode PCBDDCReuseSolversReset(PCBDDCReuseSolvers reuse)
237 {
238   PetscInt       i;
239   PetscErrorCode ierr;
240 
241   PetscFunctionBegin;
242   ierr = MatDestroy(&reuse->F);CHKERRQ(ierr);
243   ierr = VecDestroy(&reuse->sol);CHKERRQ(ierr);
244   ierr = VecDestroy(&reuse->rhs);CHKERRQ(ierr);
245   ierr = PCDestroy(&reuse->interior_solver);CHKERRQ(ierr);
246   ierr = PCDestroy(&reuse->correction_solver);CHKERRQ(ierr);
247   ierr = ISDestroy(&reuse->is_R);CHKERRQ(ierr);
248   ierr = ISDestroy(&reuse->is_B);CHKERRQ(ierr);
249   ierr = VecScatterDestroy(&reuse->correction_scatter_B);CHKERRQ(ierr);
250   ierr = VecDestroy(&reuse->sol_B);CHKERRQ(ierr);
251   ierr = VecDestroy(&reuse->rhs_B);CHKERRQ(ierr);
252   for (i=0;i<reuse->benign_n;i++) {
253     ierr = ISDestroy(&reuse->benign_zerodiag_subs[i]);CHKERRQ(ierr);
254   }
255   ierr = PetscFree(reuse->benign_zerodiag_subs);CHKERRQ(ierr);
256   ierr = PetscFree(reuse->benign_save_vals);CHKERRQ(ierr);
257   ierr = MatDestroy(&reuse->benign_csAIB);CHKERRQ(ierr);
258   ierr = MatDestroy(&reuse->benign_AIIm1ones);CHKERRQ(ierr);
259   ierr = VecDestroy(&reuse->benign_corr_work);CHKERRQ(ierr);
260   ierr = VecDestroy(&reuse->benign_dummy_schur_vec);CHKERRQ(ierr);
261   PetscFunctionReturn(0);
262 }
263 
264 #undef __FUNCT__
265 #define __FUNCT__ "PCBDDCComputeExplicitSchur"
266 static PetscErrorCode PCBDDCComputeExplicitSchur(Mat M, PetscBool issym, MatReuse reuse, Mat *S)
267 {
268   Mat            B, C, D, Bd, Cd, AinvBd;
269   KSP            ksp;
270   PC             pc;
271   PetscBool      isLU, isILU, isCHOL, Bdense, Cdense;
272   PetscReal      fill = 2.0;
273   PetscInt       n_I;
274   PetscMPIInt    size;
275   PetscErrorCode ierr;
276 
277   PetscFunctionBegin;
278   ierr = MPI_Comm_size(PetscObjectComm((PetscObject)M),&size);CHKERRQ(ierr);
279   if (size != 1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Not for parallel matrices");
280   if (reuse == MAT_REUSE_MATRIX) {
281     PetscBool Sdense;
282 
283     ierr = PetscObjectTypeCompare((PetscObject)*S, MATSEQDENSE, &Sdense);CHKERRQ(ierr);
284     if (!Sdense) SETERRQ(PetscObjectComm((PetscObject)M),PETSC_ERR_SUP,"S should dense");
285   }
286   ierr = MatSchurComplementGetSubMatrices(M, NULL, NULL, &B, &C, &D);CHKERRQ(ierr);
287   ierr = MatSchurComplementGetKSP(M, &ksp);CHKERRQ(ierr);
288   ierr = KSPGetPC(ksp, &pc);CHKERRQ(ierr);
289   ierr = PetscObjectTypeCompare((PetscObject) pc, PCLU, &isLU);CHKERRQ(ierr);
290   ierr = PetscObjectTypeCompare((PetscObject) pc, PCILU, &isILU);CHKERRQ(ierr);
291   ierr = PetscObjectTypeCompare((PetscObject) pc, PCCHOLESKY, &isCHOL);CHKERRQ(ierr);
292   ierr = PetscObjectTypeCompare((PetscObject) B, MATSEQDENSE, &Bdense);CHKERRQ(ierr);
293   ierr = PetscObjectTypeCompare((PetscObject) C, MATSEQDENSE, &Cdense);CHKERRQ(ierr);
294   ierr = MatGetSize(B,&n_I,NULL);CHKERRQ(ierr);
295   if (n_I) {
296     if (!Bdense) {
297       ierr = MatConvert(B, MATSEQDENSE, MAT_INITIAL_MATRIX, &Bd);CHKERRQ(ierr);
298     } else {
299       Bd = B;
300     }
301 
302     if (isLU || isILU || isCHOL) {
303       Mat fact;
304       ierr = KSPSetUp(ksp);CHKERRQ(ierr);
305       ierr = PCFactorGetMatrix(pc, &fact);CHKERRQ(ierr);
306       ierr = MatDuplicate(Bd, MAT_DO_NOT_COPY_VALUES, &AinvBd);CHKERRQ(ierr);
307       ierr = MatMatSolve(fact, Bd, AinvBd);CHKERRQ(ierr);
308     } else {
309       PetscBool ex = PETSC_TRUE;
310 
311       if (ex) {
312         Mat Ainvd;
313 
314         ierr = PCComputeExplicitOperator(pc, &Ainvd);CHKERRQ(ierr);
315         ierr = MatMatMult(Ainvd, Bd, MAT_INITIAL_MATRIX, fill, &AinvBd);CHKERRQ(ierr);
316         ierr = MatDestroy(&Ainvd);CHKERRQ(ierr);
317       } else {
318         Vec         sol,rhs;
319         PetscScalar *arrayrhs,*arraysol;
320         PetscInt    i,nrhs,n;
321 
322         ierr = MatDuplicate(Bd, MAT_DO_NOT_COPY_VALUES, &AinvBd);CHKERRQ(ierr);
323         ierr = MatGetSize(Bd,&n,&nrhs);CHKERRQ(ierr);
324         ierr = MatDenseGetArray(Bd,&arrayrhs);CHKERRQ(ierr);
325         ierr = MatDenseGetArray(AinvBd,&arraysol);CHKERRQ(ierr);
326         ierr = KSPGetSolution(ksp,&sol);CHKERRQ(ierr);
327         ierr = KSPGetRhs(ksp,&rhs);CHKERRQ(ierr);
328         for (i=0;i<nrhs;i++) {
329           ierr = VecPlaceArray(rhs,arrayrhs+i*n);CHKERRQ(ierr);
330           ierr = VecPlaceArray(sol,arraysol+i*n);CHKERRQ(ierr);
331           ierr = KSPSolve(ksp,rhs,sol);CHKERRQ(ierr);
332           ierr = VecResetArray(rhs);CHKERRQ(ierr);
333           ierr = VecResetArray(sol);CHKERRQ(ierr);
334         }
335         ierr = MatDenseRestoreArray(Bd,&arrayrhs);CHKERRQ(ierr);
336         ierr = MatDenseRestoreArray(AinvBd,&arrayrhs);CHKERRQ(ierr);
337       }
338     }
339     if (!Bdense & !issym) {
340       ierr = MatDestroy(&Bd);CHKERRQ(ierr);
341     }
342 
343     if (!issym) {
344       if (!Cdense) {
345         ierr = MatConvert(C, MATSEQDENSE, MAT_INITIAL_MATRIX, &Cd);CHKERRQ(ierr);
346       } else {
347         Cd = C;
348       }
349       ierr = MatMatMult(Cd, AinvBd, reuse, fill, S);CHKERRQ(ierr);
350       if (!Cdense) {
351         ierr = MatDestroy(&Cd);CHKERRQ(ierr);
352       }
353     } else {
354       ierr = MatTransposeMatMult(Bd, AinvBd, reuse, fill, S);CHKERRQ(ierr);
355       if (!Bdense) {
356         ierr = MatDestroy(&Bd);CHKERRQ(ierr);
357       }
358     }
359     ierr = MatDestroy(&AinvBd);CHKERRQ(ierr);
360   }
361 
362   if (D) {
363     Mat       Dd;
364     PetscBool Ddense;
365 
366     ierr = PetscObjectTypeCompare((PetscObject)D,MATSEQDENSE,&Ddense);CHKERRQ(ierr);
367     if (!Ddense) {
368       ierr = MatConvert(D, MATSEQDENSE, MAT_INITIAL_MATRIX, &Dd);CHKERRQ(ierr);
369     } else {
370       Dd = D;
371     }
372     if (n_I) {
373       ierr = MatAYPX(*S,-1.0,Dd,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
374     } else {
375       if (reuse == MAT_INITIAL_MATRIX) {
376         ierr = MatDuplicate(Dd,MAT_COPY_VALUES,S);CHKERRQ(ierr);
377       } else {
378         ierr = MatCopy(Dd,*S,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
379       }
380     }
381     if (!Ddense) {
382       ierr = MatDestroy(&Dd);CHKERRQ(ierr);
383     }
384   } else {
385     ierr = MatScale(*S,-1.0);CHKERRQ(ierr);
386   }
387   PetscFunctionReturn(0);
388 }
389 
390 #undef __FUNCT__
391 #define __FUNCT__ "PCBDDCSubSchursSetUp"
392 PetscErrorCode PCBDDCSubSchursSetUp(PCBDDCSubSchurs sub_schurs, Mat Ain, Mat Sin, PetscBool exact_schur, PetscInt xadj[], PetscInt adjncy[], PetscInt nlayers, Vec scaling, PetscBool compute_Stilda, PetscBool reuse_solvers, PetscBool benign_trick, PetscInt benign_n, PetscInt benign_p0_lidx[], IS benign_zerodiag_subs[], Mat change, IS change_primal)
393 {
394   Mat                    F,A_II,A_IB,A_BI,A_BB,AE_II;
395   Mat                    S_all;
396   Mat                    global_schur_subsets,work_mat,*submats;
397   ISLocalToGlobalMapping l2gmap_subsets;
398   IS                     is_I,is_I_layer;
399   IS                     all_subsets,all_subsets_mult,all_subsets_n;
400   PetscInt               *nnz,*all_local_idx_N;
401   PetscInt               *auxnum1,*auxnum2;
402   PetscInt               i,subset_size,max_subset_size;
403   PetscInt               n_B,extra,local_size,global_size;
404   PetscBLASInt           B_N,B_ierr,B_lwork,*pivots;
405   PetscScalar            *Bwork;
406   PetscSubcomm           subcomm;
407   PetscMPIInt            color,rank;
408   MPI_Comm               comm_n;
409   PetscBool              deluxe = PETSC_TRUE, use_getr = PETSC_FALSE;
410   PetscErrorCode         ierr;
411 
412   PetscFunctionBegin;
413   /* update info in sub_schurs */
414   ierr = MatDestroy(&sub_schurs->A);CHKERRQ(ierr);
415   ierr = MatDestroy(&sub_schurs->S);CHKERRQ(ierr);
416   sub_schurs->is_hermitian = PETSC_FALSE;
417   sub_schurs->is_posdef = PETSC_FALSE;
418   if (Ain) {
419     PetscBool isseqaij;
420     /* determine if we are dealing with hermitian positive definite problems */
421 #if !defined(PETSC_USE_COMPLEX)
422     if (Ain->symmetric_set) {
423       sub_schurs->is_hermitian = Ain->symmetric;
424     }
425 #else
426     if (Ain->hermitian_set) {
427       sub_schurs->is_hermitian = Ain->hermitian;
428     }
429 #endif
430     if (Ain->spd_set) {
431       sub_schurs->is_posdef = Ain->spd;
432     }
433 
434     /* check */
435     ierr = PetscObjectTypeCompare((PetscObject)Ain,MATSEQAIJ,&isseqaij);CHKERRQ(ierr);
436     if (compute_Stilda && (!Ain->hermitian_set || !Ain->spd_set)) { /* these are lazy checks, maybe I should throw an error if they are not set */
437       PetscInt lsize;
438 
439       ierr = MatGetSize(Ain,&lsize,NULL);CHKERRQ(ierr);
440       if (lsize) {
441         PetscScalar val;
442         PetscReal   norm;
443         Vec         vec1,vec2,vec3;
444 
445         ierr = MatCreateVecs(Ain,&vec1,&vec2);CHKERRQ(ierr);
446         ierr = VecDuplicate(vec1,&vec3);CHKERRQ(ierr);
447         ierr = VecSetRandom(vec1,NULL);CHKERRQ(ierr);
448         ierr = MatMult(Ain,vec1,vec2);CHKERRQ(ierr);
449 #if !defined(PETSC_USE_COMPLEX)
450         ierr = MatMultTranspose(Ain,vec1,vec3);CHKERRQ(ierr);
451 #else
452         ierr = MatMultHermitianTranspose(Ain,vec1,vec3);CHKERRQ(ierr);
453 #endif
454         ierr = VecAXPY(vec3,-1.0,vec2);CHKERRQ(ierr);
455         ierr = VecNorm(vec3,NORM_INFINITY,&norm);CHKERRQ(ierr);
456         if (!Ain->hermitian_set) {
457           if (norm > PetscSqrtReal(PETSC_SMALL)) {
458             sub_schurs->is_hermitian = PETSC_FALSE;
459           } else {
460             sub_schurs->is_hermitian = PETSC_TRUE;
461           }
462         }
463         if (!Ain->spd_set && !benign_trick) {
464           ierr = VecDot(vec1,vec2,&val);CHKERRQ(ierr);
465           if (PetscRealPart(val) > 0. && PetscAbsReal(PetscImaginaryPart(val)) < PETSC_SMALL) sub_schurs->is_posdef = PETSC_TRUE;
466         }
467         ierr = VecDestroy(&vec1);CHKERRQ(ierr);
468         ierr = VecDestroy(&vec2);CHKERRQ(ierr);
469         ierr = VecDestroy(&vec3);CHKERRQ(ierr);
470       } else {
471         sub_schurs->is_hermitian = PETSC_TRUE;
472         sub_schurs->is_posdef = PETSC_TRUE;
473       }
474     }
475     if (isseqaij) {
476       ierr = PetscObjectReference((PetscObject)Ain);CHKERRQ(ierr);
477       sub_schurs->A = Ain;
478     } else {
479       ierr = MatConvert(Ain,MATSEQAIJ,MAT_INITIAL_MATRIX,&sub_schurs->A);CHKERRQ(ierr);
480     }
481   }
482 
483   ierr = PetscObjectReference((PetscObject)Sin);CHKERRQ(ierr);
484   sub_schurs->S = Sin;
485   if (sub_schurs->schur_explicit) {
486     sub_schurs->schur_explicit = (PetscBool)(!!sub_schurs->A);
487   }
488 
489   /* preliminary checks */
490   if (!sub_schurs->schur_explicit && compute_Stilda) SETERRQ(PetscObjectComm((PetscObject)sub_schurs->l2gmap),PETSC_ERR_SUP,"Adaptive selection of constraints requires MUMPS and/or MKL_PARDISO");
491 
492   /* restrict work on active processes */
493   color = 0;
494   if (!sub_schurs->n_subs) color = 1; /* this can happen if we are in a multilevel case or if the subdomain is disconnected */
495   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)sub_schurs->l2gmap),&rank);CHKERRQ(ierr);
496   ierr = PetscSubcommCreate(PetscObjectComm((PetscObject)sub_schurs->l2gmap),&subcomm);CHKERRQ(ierr);
497   ierr = PetscSubcommSetNumber(subcomm,2);CHKERRQ(ierr);
498   ierr = PetscSubcommSetTypeGeneral(subcomm,color,rank);CHKERRQ(ierr);
499   ierr = PetscCommDuplicate(PetscSubcommChild(subcomm),&comm_n,NULL);CHKERRQ(ierr);
500   ierr = PetscSubcommDestroy(&subcomm);CHKERRQ(ierr);
501   if (!sub_schurs->n_subs) {
502     ierr = PetscCommDestroy(&comm_n);CHKERRQ(ierr);
503     PetscFunctionReturn(0);
504   }
505   /* ierr = PetscCommDuplicate(PetscObjectComm((PetscObject)sub_schurs->l2gmap),&comm_n,NULL);CHKERRQ(ierr); */
506 
507   /* get Schur complement matrices */
508   if (!sub_schurs->schur_explicit) {
509     Mat       tA_IB,tA_BI,tA_BB;
510     PetscBool isseqsbaij;
511     ierr = MatSchurComplementGetSubMatrices(sub_schurs->S,&A_II,NULL,&tA_IB,&tA_BI,&tA_BB);CHKERRQ(ierr);
512     ierr = PetscObjectTypeCompare((PetscObject)tA_BB,MATSEQSBAIJ,&isseqsbaij);CHKERRQ(ierr);
513     if (isseqsbaij) {
514       ierr = MatConvert(tA_BB,MATSEQAIJ,MAT_INITIAL_MATRIX,&A_BB);CHKERRQ(ierr);
515       ierr = MatConvert(tA_IB,MATSEQAIJ,MAT_INITIAL_MATRIX,&A_IB);CHKERRQ(ierr);
516       ierr = MatConvert(tA_BI,MATSEQAIJ,MAT_INITIAL_MATRIX,&A_BI);CHKERRQ(ierr);
517     } else {
518       ierr = PetscObjectReference((PetscObject)tA_BB);CHKERRQ(ierr);
519       A_BB = tA_BB;
520       ierr = PetscObjectReference((PetscObject)tA_IB);CHKERRQ(ierr);
521       A_IB = tA_IB;
522       ierr = PetscObjectReference((PetscObject)tA_BI);CHKERRQ(ierr);
523       A_BI = tA_BI;
524     }
525   } else {
526     A_II = NULL;
527     A_IB = NULL;
528     A_BI = NULL;
529     A_BB = NULL;
530   }
531   S_all = NULL;
532 
533   /* determine interior problems */
534   ierr = ISGetLocalSize(sub_schurs->is_I,&i);CHKERRQ(ierr);
535   if (nlayers >= 0 && i) { /* Interior problems can be different from the original one */
536     PetscBT                touched;
537     const PetscInt*        idx_B;
538     PetscInt               n_I,n_B,n_local_dofs,n_prev_added,j,layer,*local_numbering;
539 
540     if (!xadj || !adjncy) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Cannot request layering without adjacency");
541     /* get sizes */
542     ierr = ISGetLocalSize(sub_schurs->is_I,&n_I);CHKERRQ(ierr);
543     ierr = ISGetLocalSize(sub_schurs->is_B,&n_B);CHKERRQ(ierr);
544 
545     ierr = PetscMalloc1(n_I+n_B,&local_numbering);CHKERRQ(ierr);
546     ierr = PetscBTCreate(n_I+n_B,&touched);CHKERRQ(ierr);
547     ierr = PetscBTMemzero(n_I+n_B,touched);CHKERRQ(ierr);
548 
549     /* all boundary dofs must be skipped when adding layers */
550     ierr = ISGetIndices(sub_schurs->is_B,&idx_B);CHKERRQ(ierr);
551     for (j=0;j<n_B;j++) {
552       ierr = PetscBTSet(touched,idx_B[j]);CHKERRQ(ierr);
553     }
554     ierr = PetscMemcpy(local_numbering,idx_B,n_B*sizeof(PetscInt));CHKERRQ(ierr);
555     ierr = ISRestoreIndices(sub_schurs->is_B,&idx_B);CHKERRQ(ierr);
556 
557     /* add prescribed number of layers of dofs */
558     n_local_dofs = n_B;
559     n_prev_added = n_B;
560     for (layer=0;layer<nlayers;layer++) {
561       PetscInt n_added;
562       if (n_local_dofs == n_I+n_B) break;
563       if (n_local_dofs > n_I+n_B) 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);
564       ierr = PCBDDCAdjGetNextLayer_Private(local_numbering+n_local_dofs,n_prev_added,touched,xadj,adjncy,&n_added);CHKERRQ(ierr);
565       n_prev_added = n_added;
566       n_local_dofs += n_added;
567       if (!n_added) break;
568     }
569     ierr = PetscBTDestroy(&touched);CHKERRQ(ierr);
570 
571     /* IS for I layer dofs in original numbering */
572     ierr = ISCreateGeneral(PetscObjectComm((PetscObject)sub_schurs->is_I),n_local_dofs-n_B,local_numbering+n_B,PETSC_COPY_VALUES,&is_I_layer);CHKERRQ(ierr);
573     ierr = PetscFree(local_numbering);CHKERRQ(ierr);
574     ierr = ISSort(is_I_layer);CHKERRQ(ierr);
575     /* IS for I layer dofs in I numbering */
576     if (!sub_schurs->schur_explicit) {
577       ISLocalToGlobalMapping ItoNmap;
578       ierr = ISLocalToGlobalMappingCreateIS(sub_schurs->is_I,&ItoNmap);CHKERRQ(ierr);
579       ierr = ISGlobalToLocalMappingApplyIS(ItoNmap,IS_GTOLM_DROP,is_I_layer,&is_I);CHKERRQ(ierr);
580       ierr = ISLocalToGlobalMappingDestroy(&ItoNmap);CHKERRQ(ierr);
581 
582       /* II block */
583       ierr = MatGetSubMatrix(A_II,is_I,is_I,MAT_INITIAL_MATRIX,&AE_II);CHKERRQ(ierr);
584     }
585   } else {
586     PetscInt n_I;
587 
588     /* IS for I dofs in original numbering */
589     ierr = PetscObjectReference((PetscObject)sub_schurs->is_I);CHKERRQ(ierr);
590     is_I_layer = sub_schurs->is_I;
591 
592     /* IS for I dofs in I numbering (strided 1) */
593     if (!sub_schurs->schur_explicit) {
594       ierr = ISGetSize(sub_schurs->is_I,&n_I);CHKERRQ(ierr);
595       ierr = ISCreateStride(PetscObjectComm((PetscObject)sub_schurs->is_I),n_I,0,1,&is_I);CHKERRQ(ierr);
596 
597       /* II block is the same */
598       ierr = PetscObjectReference((PetscObject)A_II);CHKERRQ(ierr);
599       AE_II = A_II;
600     }
601   }
602 
603   /* Get info on subset sizes and sum of all subsets sizes */
604   max_subset_size = 0;
605   local_size = 0;
606   for (i=0;i<sub_schurs->n_subs;i++) {
607     ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
608     max_subset_size = PetscMax(subset_size,max_subset_size);
609     local_size += subset_size;
610   }
611 
612   /* Work arrays for local indices */
613   extra = 0;
614   ierr = ISGetLocalSize(sub_schurs->is_B,&n_B);CHKERRQ(ierr);
615   if (sub_schurs->schur_explicit && is_I_layer) {
616     ierr = ISGetLocalSize(is_I_layer,&extra);CHKERRQ(ierr);
617   }
618   ierr = PetscMalloc1(n_B+extra,&all_local_idx_N);CHKERRQ(ierr);
619   if (extra) {
620     const PetscInt *idxs;
621     ierr = ISGetIndices(is_I_layer,&idxs);CHKERRQ(ierr);
622     ierr = PetscMemcpy(all_local_idx_N,idxs,extra*sizeof(PetscInt));CHKERRQ(ierr);
623     ierr = ISRestoreIndices(is_I_layer,&idxs);CHKERRQ(ierr);
624   }
625   ierr = PetscMalloc1(local_size,&nnz);CHKERRQ(ierr);
626   ierr = PetscMalloc1(sub_schurs->n_subs,&auxnum1);CHKERRQ(ierr);
627   ierr = PetscMalloc1(sub_schurs->n_subs,&auxnum2);CHKERRQ(ierr);
628 
629   /* Get local indices in local numbering */
630   local_size = 0;
631   for (i=0;i<sub_schurs->n_subs;i++) {
632     PetscInt j;
633     const    PetscInt *idxs;
634 
635     ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
636     ierr = ISGetIndices(sub_schurs->is_subs[i],&idxs);CHKERRQ(ierr);
637     /* start (smallest in global ordering) and multiplicity */
638     auxnum1[i] = idxs[0];
639     auxnum2[i] = subset_size;
640     /* subset indices in local numbering */
641     ierr = PetscMemcpy(all_local_idx_N+local_size+extra,idxs,subset_size*sizeof(PetscInt));CHKERRQ(ierr);
642     ierr = ISRestoreIndices(sub_schurs->is_subs[i],&idxs);CHKERRQ(ierr);
643     for (j=0;j<subset_size;j++) nnz[local_size+j] = subset_size;
644     local_size += subset_size;
645   }
646 
647   /* allocate extra workspace needed only for GETRI */
648   Bwork = NULL;
649   pivots = NULL;
650   if (local_size && !benign_trick && (!sub_schurs->is_hermitian || !sub_schurs->is_posdef)) {
651     PetscScalar lwork;
652 
653     use_getr = PETSC_TRUE;
654     B_lwork = -1;
655     ierr = PetscBLASIntCast(local_size,&B_N);CHKERRQ(ierr);
656     ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
657     PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,Bwork,&B_N,pivots,&lwork,&B_lwork,&B_ierr));
658     ierr = PetscFPTrapPop();CHKERRQ(ierr);
659     if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in query to GETRI Lapack routine %d",(int)B_ierr);
660     ierr = PetscBLASIntCast((PetscInt)PetscRealPart(lwork),&B_lwork);CHKERRQ(ierr);
661     ierr = PetscMalloc2(B_lwork,&Bwork,B_N,&pivots);CHKERRQ(ierr);
662   }
663 
664   /* prepare parallel matrices for summing up properly schurs on subsets */
665   ierr = ISCreateGeneral(comm_n,sub_schurs->n_subs,auxnum1,PETSC_OWN_POINTER,&all_subsets_n);CHKERRQ(ierr);
666   ierr = ISLocalToGlobalMappingApplyIS(sub_schurs->l2gmap,all_subsets_n,&all_subsets);CHKERRQ(ierr);
667   ierr = ISDestroy(&all_subsets_n);CHKERRQ(ierr);
668   ierr = ISCreateGeneral(comm_n,sub_schurs->n_subs,auxnum2,PETSC_OWN_POINTER,&all_subsets_mult);CHKERRQ(ierr);
669   ierr = PCBDDCSubsetNumbering(all_subsets,all_subsets_mult,&global_size,&all_subsets_n);CHKERRQ(ierr);
670   ierr = ISDestroy(&all_subsets);CHKERRQ(ierr);
671   ierr = ISDestroy(&all_subsets_mult);CHKERRQ(ierr);
672   ierr = ISGetLocalSize(all_subsets_n,&i);CHKERRQ(ierr);
673   if (i != local_size) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Invalid size of new subset! %D != %D",i,local_size);
674   ierr = ISLocalToGlobalMappingCreateIS(all_subsets_n,&l2gmap_subsets);CHKERRQ(ierr);
675   ierr = MatCreateIS(comm_n,1,PETSC_DECIDE,PETSC_DECIDE,global_size,global_size,l2gmap_subsets,NULL,&work_mat);CHKERRQ(ierr);
676   ierr = ISLocalToGlobalMappingDestroy(&l2gmap_subsets);CHKERRQ(ierr);
677   ierr = MatCreate(PetscObjectComm((PetscObject)work_mat),&global_schur_subsets);CHKERRQ(ierr);
678   ierr = MatSetSizes(global_schur_subsets,PETSC_DECIDE,PETSC_DECIDE,global_size,global_size);CHKERRQ(ierr);
679   ierr = MatSetType(global_schur_subsets,MATMPIAIJ);CHKERRQ(ierr);
680 
681   /* subset indices in local boundary numbering */
682   if (!sub_schurs->is_Ej_all) {
683     PetscInt *all_local_idx_B;
684 
685     ierr = PetscMalloc1(local_size,&all_local_idx_B);CHKERRQ(ierr);
686     ierr = ISGlobalToLocalMappingApply(sub_schurs->BtoNmap,IS_GTOLM_DROP,local_size,all_local_idx_N+extra,&subset_size,all_local_idx_B);CHKERRQ(ierr);
687     if (subset_size != local_size) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Error in sub_schurs serial (BtoNmap)! %D != %D\n",subset_size,local_size);
688     ierr = ISCreateGeneral(PETSC_COMM_SELF,local_size,all_local_idx_B,PETSC_OWN_POINTER,&sub_schurs->is_Ej_all);CHKERRQ(ierr);
689   }
690 
691   if (change) {
692     ISLocalToGlobalMapping BtoS;
693     IS                     change_primal_B;
694     IS                     change_primal_all;
695 
696     if (sub_schurs->change_primal_sub) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"This should not happen");
697     if (sub_schurs->change) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"This should not happen");
698     ierr = PetscMalloc1(sub_schurs->n_subs,&sub_schurs->change_primal_sub);CHKERRQ(ierr);
699     for (i=0;i<sub_schurs->n_subs;i++) {
700       ISLocalToGlobalMapping NtoS;
701       ierr = ISLocalToGlobalMappingCreateIS(sub_schurs->is_subs[i],&NtoS);CHKERRQ(ierr);
702       ierr = ISGlobalToLocalMappingApplyIS(NtoS,IS_GTOLM_DROP,change_primal,&sub_schurs->change_primal_sub[i]);CHKERRQ(ierr);
703       ierr = ISLocalToGlobalMappingDestroy(&NtoS);CHKERRQ(ierr);
704     }
705     ierr = ISGlobalToLocalMappingApplyIS(sub_schurs->BtoNmap,IS_GTOLM_DROP,change_primal,&change_primal_B);CHKERRQ(ierr);
706     ierr = ISLocalToGlobalMappingCreateIS(sub_schurs->is_Ej_all,&BtoS);CHKERRQ(ierr);
707     ierr = ISGlobalToLocalMappingApplyIS(BtoS,IS_GTOLM_DROP,change_primal_B,&change_primal_all);CHKERRQ(ierr);
708     ierr = ISLocalToGlobalMappingDestroy(&BtoS);CHKERRQ(ierr);
709     ierr = ISDestroy(&change_primal_B);CHKERRQ(ierr);
710     ierr = PetscMalloc1(sub_schurs->n_subs,&sub_schurs->change);CHKERRQ(ierr);
711     for (i=0;i<sub_schurs->n_subs;i++) {
712       Mat change_sub;
713 
714       ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
715       ierr = KSPCreate(PETSC_COMM_SELF,&sub_schurs->change[i]);CHKERRQ(ierr);
716       ierr = KSPSetType(sub_schurs->change[i],KSPPREONLY);CHKERRQ(ierr);
717       if (!sub_schurs->change_with_qr) {
718         ierr = MatGetSubMatrix(change,sub_schurs->is_subs[i],sub_schurs->is_subs[i],MAT_INITIAL_MATRIX,&change_sub);CHKERRQ(ierr);
719       } else {
720         Mat change_subt;
721         ierr = MatGetSubMatrix(change,sub_schurs->is_subs[i],sub_schurs->is_subs[i],MAT_INITIAL_MATRIX,&change_subt);CHKERRQ(ierr);
722         ierr = MatConvert(change_subt,MATSEQDENSE,MAT_INITIAL_MATRIX,&change_sub);CHKERRQ(ierr);
723         ierr = MatDestroy(&change_subt);CHKERRQ(ierr);
724       }
725       ierr = KSPSetOperators(sub_schurs->change[i],change_sub,change_sub);CHKERRQ(ierr);
726       ierr = MatDestroy(&change_sub);CHKERRQ(ierr);
727       ierr = KSPSetOptionsPrefix(sub_schurs->change[i],"sub_schurs_change_");CHKERRQ(ierr);
728     }
729     ierr = ISDestroy(&change_primal_all);CHKERRQ(ierr);
730   }
731 
732   /* Local matrix of all local Schur on subsets (transposed) */
733   if (!sub_schurs->S_Ej_all) {
734     ierr = MatCreate(PETSC_COMM_SELF,&sub_schurs->S_Ej_all);CHKERRQ(ierr);
735     ierr = MatSetSizes(sub_schurs->S_Ej_all,PETSC_DECIDE,PETSC_DECIDE,local_size,local_size);CHKERRQ(ierr);
736     ierr = MatSetType(sub_schurs->S_Ej_all,MATAIJ);CHKERRQ(ierr);
737     ierr = MatSeqAIJSetPreallocation(sub_schurs->S_Ej_all,0,nnz);CHKERRQ(ierr);
738   }
739 
740   /* Compute Schur complements explicitly */
741   F = NULL;
742   if (!sub_schurs->schur_explicit) { /* this code branch is used when MatFactor with Schur complemnent support is not present; it is not very efficient, unless the economic version of the scaling is required */
743     Mat         S_Ej_expl;
744     PetscScalar *work;
745     PetscInt    j,*dummy_idx;
746     PetscBool   Sdense;
747 
748     ierr = PetscMalloc2(max_subset_size,&dummy_idx,max_subset_size*max_subset_size,&work);CHKERRQ(ierr);
749     local_size = 0;
750     for (i=0;i<sub_schurs->n_subs;i++) {
751       IS  is_subset_B;
752       Mat AE_EE,AE_IE,AE_EI,S_Ej;
753 
754       /* subsets in original and boundary numbering */
755       ierr = ISGlobalToLocalMappingApplyIS(sub_schurs->BtoNmap,IS_GTOLM_DROP,sub_schurs->is_subs[i],&is_subset_B);CHKERRQ(ierr);
756       /* EE block */
757       ierr = MatGetSubMatrix(A_BB,is_subset_B,is_subset_B,MAT_INITIAL_MATRIX,&AE_EE);CHKERRQ(ierr);
758       /* IE block */
759       ierr = MatGetSubMatrix(A_IB,is_I,is_subset_B,MAT_INITIAL_MATRIX,&AE_IE);CHKERRQ(ierr);
760       /* EI block */
761       if (sub_schurs->is_hermitian) {
762         ierr = MatCreateTranspose(AE_IE,&AE_EI);CHKERRQ(ierr);
763       } else {
764         ierr = MatGetSubMatrix(A_BI,is_subset_B,is_I,MAT_INITIAL_MATRIX,&AE_EI);CHKERRQ(ierr);
765       }
766       ierr = ISDestroy(&is_subset_B);CHKERRQ(ierr);
767       ierr = MatCreateSchurComplement(AE_II,AE_II,AE_IE,AE_EI,AE_EE,&S_Ej);CHKERRQ(ierr);
768       ierr = MatDestroy(&AE_EE);CHKERRQ(ierr);
769       ierr = MatDestroy(&AE_IE);CHKERRQ(ierr);
770       ierr = MatDestroy(&AE_EI);CHKERRQ(ierr);
771       if (AE_II == A_II) { /* we can reuse the same ksp */
772         KSP ksp;
773         ierr = MatSchurComplementGetKSP(sub_schurs->S,&ksp);CHKERRQ(ierr);
774         ierr = MatSchurComplementSetKSP(S_Ej,ksp);CHKERRQ(ierr);
775       } else { /* build new ksp object which inherits ksp and pc types from the original one */
776         KSP       origksp,schurksp;
777         PC        origpc,schurpc;
778         KSPType   ksp_type;
779         PetscInt  n_internal;
780         PetscBool ispcnone;
781 
782         ierr = MatSchurComplementGetKSP(sub_schurs->S,&origksp);CHKERRQ(ierr);
783         ierr = MatSchurComplementGetKSP(S_Ej,&schurksp);CHKERRQ(ierr);
784         ierr = KSPGetType(origksp,&ksp_type);CHKERRQ(ierr);
785         ierr = KSPSetType(schurksp,ksp_type);CHKERRQ(ierr);
786         ierr = KSPGetPC(schurksp,&schurpc);CHKERRQ(ierr);
787         ierr = KSPGetPC(origksp,&origpc);CHKERRQ(ierr);
788         ierr = PetscObjectTypeCompare((PetscObject)origpc,PCNONE,&ispcnone);CHKERRQ(ierr);
789         if (!ispcnone) {
790           PCType pc_type;
791           ierr = PCGetType(origpc,&pc_type);CHKERRQ(ierr);
792           ierr = PCSetType(schurpc,pc_type);CHKERRQ(ierr);
793         } else {
794           ierr = PCSetType(schurpc,PCLU);CHKERRQ(ierr);
795         }
796         ierr = ISGetSize(is_I,&n_internal);CHKERRQ(ierr);
797         if (n_internal) { /* UMFPACK gives error with 0 sized problems */
798           MatSolverPackage solver=NULL;
799           ierr = PCFactorGetMatSolverPackage(origpc,(const MatSolverPackage*)&solver);CHKERRQ(ierr);
800           if (solver) {
801             ierr = PCFactorSetMatSolverPackage(schurpc,solver);CHKERRQ(ierr);
802           }
803         }
804         ierr = KSPSetUp(schurksp);CHKERRQ(ierr);
805       }
806       ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
807       ierr = MatCreateSeqDense(PETSC_COMM_SELF,subset_size,subset_size,work,&S_Ej_expl);CHKERRQ(ierr);
808       ierr = PCBDDCComputeExplicitSchur(S_Ej,sub_schurs->is_hermitian,MAT_REUSE_MATRIX,&S_Ej_expl);CHKERRQ(ierr);
809       ierr = PetscObjectTypeCompare((PetscObject)S_Ej_expl,MATSEQDENSE,&Sdense);CHKERRQ(ierr);
810       if (Sdense) {
811         for (j=0;j<subset_size;j++) {
812           dummy_idx[j]=local_size+j;
813         }
814         ierr = MatSetValues(sub_schurs->S_Ej_all,subset_size,dummy_idx,subset_size,dummy_idx,work,INSERT_VALUES);CHKERRQ(ierr);
815       } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Not yet implemented for sparse matrices");
816       ierr = MatDestroy(&S_Ej);CHKERRQ(ierr);
817       ierr = MatDestroy(&S_Ej_expl);CHKERRQ(ierr);
818       local_size += subset_size;
819     }
820     ierr = PetscFree2(dummy_idx,work);CHKERRQ(ierr);
821     /* free */
822     ierr = ISDestroy(&is_I);CHKERRQ(ierr);
823     ierr = MatDestroy(&AE_II);CHKERRQ(ierr);
824     ierr = PetscFree(all_local_idx_N);CHKERRQ(ierr);
825   } else {
826     Mat         A,cs_AIB_mat = NULL,benign_AIIm1_ones_mat = NULL;
827     Vec         Dall = NULL;
828     IS          is_A_all,*is_p_r = NULL;
829     PetscScalar *work,*S_data,*schur_factor,infty = PETSC_MAX_REAL;
830     PetscInt    n,n_I,*dummy_idx,size_schur,size_active_schur,cum,cum2;
831     PetscBool   economic,solver_S,S_lower_triangular = PETSC_FALSE,factor_workaround;
832     char        solver[256];
833 
834     /* get sizes */
835     n_I = 0;
836     if (is_I_layer) {
837       ierr = ISGetLocalSize(is_I_layer,&n_I);CHKERRQ(ierr);
838     }
839     economic = PETSC_FALSE;
840     ierr = ISGetLocalSize(sub_schurs->is_I,&cum);CHKERRQ(ierr);
841     if (cum != n_I) economic = PETSC_TRUE;
842     ierr = MatGetLocalSize(sub_schurs->A,&n,NULL);CHKERRQ(ierr);
843     size_active_schur = local_size;
844 
845     /* import scaling vector */
846     if (scaling && compute_Stilda) {
847       const PetscScalar *array;
848       PetscScalar       *array2;
849       const PetscInt    *idxs;
850       PetscInt          i;
851 
852       ierr = ISGetIndices(sub_schurs->is_Ej_all,&idxs);CHKERRQ(ierr);
853       ierr = VecCreateSeq(PETSC_COMM_SELF,size_active_schur,&Dall);CHKERRQ(ierr);
854       ierr = VecGetArrayRead(scaling,&array);CHKERRQ(ierr);
855       ierr = VecGetArray(Dall,&array2);CHKERRQ(ierr);
856       for (i=0;i<size_active_schur;i++) array2[i] = array[idxs[i]];
857       ierr = VecRestoreArray(Dall,&array2);CHKERRQ(ierr);
858       ierr = VecRestoreArrayRead(scaling,&array);CHKERRQ(ierr);
859       ierr = ISRestoreIndices(sub_schurs->is_Ej_all,&idxs);CHKERRQ(ierr);
860       deluxe = PETSC_FALSE;
861     }
862 
863     /* size active schurs does not count any dirichlet or vertex dof on the interface */
864     cum = n_I+size_active_schur;
865     if (sub_schurs->is_dir) {
866       const PetscInt* idxs;
867       PetscInt        n_dir;
868 
869       ierr = ISGetLocalSize(sub_schurs->is_dir,&n_dir);CHKERRQ(ierr);
870       ierr = ISGetIndices(sub_schurs->is_dir,&idxs);CHKERRQ(ierr);
871       ierr = PetscMemcpy(all_local_idx_N+cum,idxs,n_dir*sizeof(PetscInt));CHKERRQ(ierr);
872       ierr = ISRestoreIndices(sub_schurs->is_dir,&idxs);CHKERRQ(ierr);
873       cum += n_dir;
874     }
875     factor_workaround = PETSC_FALSE;
876     /* include the primal vertices in the Schur complement */
877     if (exact_schur && sub_schurs->is_vertices && (compute_Stilda || benign_n)) {
878       PetscInt n_v;
879 
880       ierr = ISGetLocalSize(sub_schurs->is_vertices,&n_v);CHKERRQ(ierr);
881       if (n_v) {
882         const PetscInt* idxs;
883 
884         ierr = ISGetIndices(sub_schurs->is_vertices,&idxs);CHKERRQ(ierr);
885         ierr = PetscMemcpy(all_local_idx_N+cum,idxs,n_v*sizeof(PetscInt));CHKERRQ(ierr);
886         ierr = ISRestoreIndices(sub_schurs->is_vertices,&idxs);CHKERRQ(ierr);
887         cum += n_v;
888         factor_workaround = PETSC_TRUE;
889       }
890     }
891     size_schur = cum - n_I;
892     ierr = ISCreateGeneral(PETSC_COMM_SELF,cum,all_local_idx_N,PETSC_OWN_POINTER,&is_A_all);CHKERRQ(ierr);
893     /* get working mat (TODO: factorize without actually permuting)  */
894     if (cum == n) {
895       ierr = ISSetPermutation(is_A_all);CHKERRQ(ierr);
896       ierr = MatPermute(sub_schurs->A,is_A_all,is_A_all,&A);CHKERRQ(ierr);
897     } else {
898       ierr = MatGetSubMatrix(sub_schurs->A,is_A_all,is_A_all,MAT_INITIAL_MATRIX,&A);CHKERRQ(ierr);
899     }
900     ierr = MatSetOptionsPrefix(A,"sub_schurs_");CHKERRQ(ierr);
901 
902     /* if we actually change the basis for the pressures, LDL^T factors will use a lot of memory
903        n^2 instead of n^1.5 or something. This is a workaround */
904     if (benign_n) {
905       Vec                    v;
906       ISLocalToGlobalMapping N_to_reor;
907       IS                     is_p0,is_p0_p;
908       PetscScalar            *cs_AIB,*AIIm1_data;
909       PetscInt               sizeA;
910 
911       ierr = ISLocalToGlobalMappingCreateIS(is_A_all,&N_to_reor);CHKERRQ(ierr);
912       ierr = ISCreateGeneral(PETSC_COMM_SELF,benign_n,benign_p0_lidx,PETSC_COPY_VALUES,&is_p0);CHKERRQ(ierr);
913       ierr = ISGlobalToLocalMappingApplyIS(N_to_reor,IS_GTOLM_DROP,is_p0,&is_p0_p);CHKERRQ(ierr);
914       ierr = ISDestroy(&is_p0);CHKERRQ(ierr);
915       ierr = MatCreateVecs(A,&v,NULL);CHKERRQ(ierr);
916       ierr = VecGetSize(v,&sizeA);CHKERRQ(ierr);
917       ierr = MatCreateSeqDense(PETSC_COMM_SELF,sizeA,benign_n,NULL,&benign_AIIm1_ones_mat);CHKERRQ(ierr);
918       ierr = MatCreateSeqDense(PETSC_COMM_SELF,benign_n,size_schur,NULL,&cs_AIB_mat);CHKERRQ(ierr);
919       ierr = MatDenseGetArray(cs_AIB_mat,&cs_AIB);CHKERRQ(ierr);
920       ierr = MatDenseGetArray(benign_AIIm1_ones_mat,&AIIm1_data);CHKERRQ(ierr);
921       ierr = PetscMalloc1(benign_n,&is_p_r);CHKERRQ(ierr);
922       /* compute colsum of A_IB restricted to pressures */
923       for (i=0;i<benign_n;i++) {
924         Vec            benign_AIIm1_ones;
925         PetscScalar    *array;
926         const PetscInt *idxs;
927         PetscInt       j,nz;
928 
929         ierr = ISGlobalToLocalMappingApplyIS(N_to_reor,IS_GTOLM_DROP,benign_zerodiag_subs[i],&is_p_r[i]);CHKERRQ(ierr);
930         ierr = ISGetLocalSize(is_p_r[i],&nz);CHKERRQ(ierr);
931         ierr = ISGetIndices(is_p_r[i],&idxs);CHKERRQ(ierr);
932         for (j=0;j<nz;j++) AIIm1_data[idxs[j]+sizeA*i] = 1.;
933         ierr = ISRestoreIndices(is_p_r[i],&idxs);CHKERRQ(ierr);
934         ierr = VecCreateSeqWithArray(PETSC_COMM_SELF,1,sizeA,AIIm1_data+sizeA*i,&benign_AIIm1_ones);CHKERRQ(ierr);
935         ierr = MatMult(A,benign_AIIm1_ones,v);CHKERRQ(ierr);
936         ierr = VecDestroy(&benign_AIIm1_ones);CHKERRQ(ierr);
937         ierr = VecGetArray(v,&array);CHKERRQ(ierr);
938         for (j=0;j<size_schur;j++) cs_AIB[i*size_schur + j] = array[j+n_I]/nz;
939         ierr = VecRestoreArray(v,&array);CHKERRQ(ierr);
940       }
941       ierr = MatDenseRestoreArray(cs_AIB_mat,&cs_AIB);CHKERRQ(ierr);
942       ierr = MatDenseRestoreArray(benign_AIIm1_ones_mat,&AIIm1_data);CHKERRQ(ierr);
943       ierr = VecDestroy(&v);CHKERRQ(ierr);
944       ierr = MatSetOption(A,MAT_KEEP_NONZERO_PATTERN,PETSC_FALSE);CHKERRQ(ierr);
945       ierr = MatZeroRowsColumnsIS(A,is_p0_p,1.0,NULL,NULL);CHKERRQ(ierr);
946       ierr = ISDestroy(&is_p0_p);CHKERRQ(ierr);
947       ierr = ISLocalToGlobalMappingDestroy(&N_to_reor);CHKERRQ(ierr);
948     }
949     ierr = MatSetOption(A,MAT_SYMMETRIC,sub_schurs->is_hermitian);CHKERRQ(ierr);
950     ierr = MatSetOption(A,MAT_HERMITIAN,sub_schurs->is_hermitian);CHKERRQ(ierr);
951     ierr = MatSetOption(A,MAT_SPD,sub_schurs->is_posdef);CHKERRQ(ierr);
952 #if defined(PETSC_HAVE_MUMPS)
953     ierr = PetscStrcpy(solver,MATSOLVERMUMPS);CHKERRQ(ierr);
954 #else
955     ierr = PetscStrcpy(solver,MATSOLVERMKL_PARDISO);CHKERRQ(ierr);
956 #endif
957     ierr = PetscOptionsGetString(NULL,"sub_schurs_","-mat_solver_package",solver,256,NULL);CHKERRQ(ierr);
958 
959     /* when using the benign subspace trick, the local Schur complements are SPD */
960     if (benign_trick) sub_schurs->is_posdef = PETSC_TRUE;
961 
962     if (n_I) { /* TODO add ordering from options */
963       IS is_schur;
964 
965       if (sub_schurs->is_hermitian && sub_schurs->is_posdef) {
966         ierr = MatGetFactor(A,solver,MAT_FACTOR_CHOLESKY,&F);CHKERRQ(ierr);
967       } else {
968         ierr = MatGetFactor(A,solver,MAT_FACTOR_LU,&F);CHKERRQ(ierr);
969       }
970       /* subsets ordered last */
971       ierr = ISCreateStride(PETSC_COMM_SELF,size_schur,n_I,1,&is_schur);CHKERRQ(ierr);
972       ierr = MatFactorSetSchurIS(F,is_schur);CHKERRQ(ierr);
973       ierr = ISDestroy(&is_schur);CHKERRQ(ierr);
974 
975       /* factorization step */
976       if (sub_schurs->is_hermitian && sub_schurs->is_posdef) {
977         ierr = MatCholeskyFactorSymbolic(F,A,NULL,NULL);CHKERRQ(ierr);
978 #if defined(PETSC_HAVE_MUMPS) /* be sure that icntl 19 is not set by command line */
979         ierr = MatMumpsSetIcntl(F,19,2);CHKERRQ(ierr);
980 #endif
981         if (sub_schurs->is_posdef) {
982           ierr = MatFactorSetSchurComplementSolverType(F,1);CHKERRQ(ierr);
983         } else {
984           ierr = MatFactorSetSchurComplementSolverType(F,2);CHKERRQ(ierr);
985         }
986         ierr = MatCholeskyFactorNumeric(F,A,NULL);CHKERRQ(ierr);
987         S_lower_triangular = PETSC_TRUE;
988       } else {
989         ierr = MatLUFactorSymbolic(F,A,NULL,NULL,NULL);CHKERRQ(ierr);
990 #if defined(PETSC_HAVE_MUMPS) /* be sure that icntl 19 is not set by command line */
991         ierr = MatMumpsSetIcntl(F,19,3);CHKERRQ(ierr);
992 #endif
993         ierr = MatLUFactorNumeric(F,A,NULL);CHKERRQ(ierr);
994       }
995 
996       /* get explicit Schur Complement computed during numeric factorization */
997       ierr = MatFactorGetSchurComplement(F,&S_all);CHKERRQ(ierr);
998       /* we can reuse the solvers if we are not using the economic version */
999       reuse_solvers = (PetscBool)(reuse_solvers && !economic);
1000       factor_workaround = (PetscBool)(reuse_solvers && factor_workaround);
1001       solver_S = PETSC_TRUE;
1002 
1003       /* update the Schur complement with the change of basis on the pressures */
1004       if (benign_n) {
1005         PetscScalar *S_data,*cs_AIB,*AIIm1_data;
1006         Vec         v;
1007         PetscInt    sizeA;
1008 
1009         ierr = MatDenseGetArray(S_all,&S_data);CHKERRQ(ierr);
1010         ierr = MatCreateVecs(A,&v,NULL);CHKERRQ(ierr);
1011         ierr = VecGetSize(v,&sizeA);CHKERRQ(ierr);
1012 #if defined(PETSC_HAVE_MUMPS)
1013         ierr = MatMumpsSetIcntl(F,26,0);CHKERRQ(ierr);
1014 #endif
1015 #if defined(PETSC_HAVE_MKL_PARDISO)
1016         ierr = MatMkl_PardisoSetCntl(F,70,1);CHKERRQ(ierr);
1017 #endif
1018         ierr = MatDenseGetArray(cs_AIB_mat,&cs_AIB);CHKERRQ(ierr);
1019         ierr = MatDenseGetArray(benign_AIIm1_ones_mat,&AIIm1_data);CHKERRQ(ierr);
1020         for (i=0;i<benign_n;i++) {
1021           Vec            benign_AIIm1_ones;
1022           PetscScalar    *array,sum = 0.,one = 1.;
1023           const PetscInt *idxs;
1024           PetscInt       j,nz;
1025           PetscBLASInt   B_k,B_n;
1026 
1027           ierr = VecCreateSeqWithArray(PETSC_COMM_SELF,1,sizeA,AIIm1_data+sizeA*i,&benign_AIIm1_ones);CHKERRQ(ierr);
1028           ierr = VecCopy(benign_AIIm1_ones,v);CHKERRQ(ierr);
1029           ierr = MatSolve(F,v,benign_AIIm1_ones);CHKERRQ(ierr);
1030           ierr = ISGetLocalSize(is_p_r[i],&nz);CHKERRQ(ierr);
1031           ierr = ISGetIndices(is_p_r[i],&idxs);CHKERRQ(ierr);
1032           for (j=0;j<nz;j++) sum += AIIm1_data[idxs[j]+sizeA*i];
1033           sum -= 1.; /* p0 dof (eliminated) is excluded from the sum */
1034           ierr = ISRestoreIndices(is_p_r[i],&idxs);CHKERRQ(ierr);
1035           ierr = MatMult(A,benign_AIIm1_ones,v);CHKERRQ(ierr);
1036           ierr = VecGetArray(v,&array);CHKERRQ(ierr);
1037           /* perform sparse rank updates on symmetric Schur (TODO: move outside of the loop?) */
1038           /* cs_AIB already scaled by 1./nz */
1039           sum  = -sum;
1040           B_k = 1;
1041           ierr = PetscBLASIntCast(size_schur,&B_n);CHKERRQ(ierr);
1042           PetscStackCallBLAS("BLASsyrk",BLASsyrk_("L","N",&B_n,&B_k,&sum,cs_AIB+i*size_schur,&B_n,&one,S_data,&B_n));
1043           sum  = 1.;
1044           PetscStackCallBLAS("BLASsyr2k",BLASsyr2k_("L","N",&B_n,&B_k,&sum,array+n_I,&B_n,cs_AIB+i*size_schur,&B_n,&one,S_data,&B_n));
1045           ierr = VecRestoreArray(v,&array);CHKERRQ(ierr);
1046           /* set p0 entry of AIIm1_ones to zero */
1047           ierr = ISGetIndices(is_p_r[i],&idxs);CHKERRQ(ierr);
1048           AIIm1_data[idxs[nz-1]+sizeA*i] = 0.;
1049           ierr = ISRestoreIndices(is_p_r[i],&idxs);CHKERRQ(ierr);
1050           ierr = VecDestroy(&benign_AIIm1_ones);CHKERRQ(ierr);
1051         }
1052   /* restore defaults */
1053 #if defined(PETSC_HAVE_MUMPS)
1054         ierr = MatMumpsSetIcntl(F,26,-1);CHKERRQ(ierr);
1055 #endif
1056 #if defined(PETSC_HAVE_MKL_PARDISO)
1057         ierr = MatMkl_PardisoSetCntl(F,70,0);CHKERRQ(ierr);
1058 #endif
1059         ierr = MatDenseRestoreArray(cs_AIB_mat,&cs_AIB);CHKERRQ(ierr);
1060         ierr = MatDenseRestoreArray(benign_AIIm1_ones_mat,&AIIm1_data);CHKERRQ(ierr);
1061         ierr = VecDestroy(&v);CHKERRQ(ierr);
1062         ierr = MatDenseRestoreArray(S_all,&S_data);CHKERRQ(ierr);
1063       }
1064       if (!reuse_solvers) {
1065         for (i=0;i<benign_n;i++) {
1066           ierr = ISDestroy(&is_p_r[i]);CHKERRQ(ierr);
1067         }
1068         ierr = PetscFree(is_p_r);CHKERRQ(ierr);
1069         ierr = MatDestroy(&cs_AIB_mat);CHKERRQ(ierr);
1070         ierr = MatDestroy(&benign_AIIm1_ones_mat);CHKERRQ(ierr);
1071       }
1072     } else { /* we can't use MatFactor when size_schur == size_of_the_problem */
1073       ierr = MatConvert(A,MATSEQDENSE,MAT_INITIAL_MATRIX,&S_all);CHKERRQ(ierr);
1074       reuse_solvers = PETSC_FALSE; /* TODO: why we can't reuse the solvers here? */
1075       solver_S = PETSC_FALSE;
1076     }
1077 
1078     if (reuse_solvers) {
1079       Mat                A_II,Afake;
1080       Vec                vec1_B;
1081       PCBDDCReuseSolvers msolv_ctx;
1082       PetscInt           n_R;
1083 
1084       if (sub_schurs->reuse_solver) {
1085         ierr = PCBDDCReuseSolversReset(sub_schurs->reuse_solver);CHKERRQ(ierr);
1086       } else {
1087         ierr = PetscNew(&sub_schurs->reuse_solver);CHKERRQ(ierr);
1088       }
1089       msolv_ctx = sub_schurs->reuse_solver;
1090       ierr = MatSchurComplementGetSubMatrices(sub_schurs->S,&A_II,NULL,NULL,NULL,NULL);CHKERRQ(ierr);
1091       ierr = PetscObjectReference((PetscObject)F);CHKERRQ(ierr);
1092       msolv_ctx->F = F;
1093       ierr = MatCreateVecs(F,&msolv_ctx->sol,NULL);CHKERRQ(ierr);
1094       /* currently PETSc has no support for MatSolve(F,x,x), so cheat and let rhs and sol share the same memory */
1095       {
1096         PetscScalar *array;
1097         PetscInt    n;
1098 
1099         ierr = VecGetLocalSize(msolv_ctx->sol,&n);CHKERRQ(ierr);
1100         ierr = VecGetArray(msolv_ctx->sol,&array);CHKERRQ(ierr);
1101         ierr = VecCreateSeqWithArray(PetscObjectComm((PetscObject)msolv_ctx->sol),1,n,array,&msolv_ctx->rhs);CHKERRQ(ierr);
1102         ierr = VecRestoreArray(msolv_ctx->sol,&array);CHKERRQ(ierr);
1103       }
1104       msolv_ctx->has_vertices = factor_workaround;
1105 
1106       /* interior solver */
1107       ierr = PCCreate(PetscObjectComm((PetscObject)A_II),&msolv_ctx->interior_solver);CHKERRQ(ierr);
1108       ierr = PCSetOperators(msolv_ctx->interior_solver,A_II,A_II);CHKERRQ(ierr);
1109       ierr = PCSetType(msolv_ctx->interior_solver,PCSHELL);CHKERRQ(ierr);
1110       ierr = PCShellSetContext(msolv_ctx->interior_solver,msolv_ctx);CHKERRQ(ierr);
1111       ierr = PCShellSetApply(msolv_ctx->interior_solver,PCBDDCReuseSolvers_Interior);CHKERRQ(ierr);
1112       ierr = PCShellSetApplyTranspose(msolv_ctx->interior_solver,PCBDDCReuseSolvers_InteriorTranspose);CHKERRQ(ierr);
1113 
1114       /* correction solver */
1115       ierr = PCCreate(PetscObjectComm((PetscObject)A_II),&msolv_ctx->correction_solver);CHKERRQ(ierr);
1116       ierr = PCSetType(msolv_ctx->correction_solver,PCSHELL);CHKERRQ(ierr);
1117       ierr = PCShellSetContext(msolv_ctx->correction_solver,msolv_ctx);CHKERRQ(ierr);
1118       ierr = PCShellSetApply(msolv_ctx->correction_solver,PCBDDCReuseSolvers_Correction);CHKERRQ(ierr);
1119       ierr = PCShellSetApplyTranspose(msolv_ctx->correction_solver,PCBDDCReuseSolvers_CorrectionTranspose);CHKERRQ(ierr);
1120 
1121       /* scatter and vecs for Schur complement solver */
1122       ierr = MatCreateVecs(S_all,&msolv_ctx->sol_B,&msolv_ctx->rhs_B);CHKERRQ(ierr);
1123       ierr = MatCreateVecs(sub_schurs->S,&vec1_B,NULL);CHKERRQ(ierr);
1124       if (!factor_workaround) {
1125         ierr = ISGlobalToLocalMappingApplyIS(sub_schurs->BtoNmap,IS_GTOLM_DROP,is_A_all,&msolv_ctx->is_B);CHKERRQ(ierr);
1126         ierr = VecScatterCreate(vec1_B,msolv_ctx->is_B,msolv_ctx->sol_B,NULL,&msolv_ctx->correction_scatter_B);CHKERRQ(ierr);
1127         ierr = PetscObjectReference((PetscObject)is_A_all);CHKERRQ(ierr);
1128         msolv_ctx->is_R = is_A_all;
1129       } else {
1130         IS              is_B_all;
1131         const PetscInt* idxs;
1132         PetscInt        dual,n_v,n;
1133 
1134         ierr = ISGetLocalSize(sub_schurs->is_vertices,&n_v);CHKERRQ(ierr);
1135         dual = size_schur - n_v;
1136         ierr = ISGetLocalSize(is_A_all,&n);CHKERRQ(ierr);
1137         ierr = ISGetIndices(is_A_all,&idxs);CHKERRQ(ierr);
1138         ierr = ISCreateGeneral(PetscObjectComm((PetscObject)is_A_all),dual,idxs+n_I,PETSC_COPY_VALUES,&is_B_all);CHKERRQ(ierr);
1139         ierr = ISGlobalToLocalMappingApplyIS(sub_schurs->BtoNmap,IS_GTOLM_DROP,is_B_all,&msolv_ctx->is_B);CHKERRQ(ierr);
1140         ierr = ISDestroy(&is_B_all);CHKERRQ(ierr);
1141         ierr = ISCreateStride(PetscObjectComm((PetscObject)is_A_all),dual,0,1,&is_B_all);CHKERRQ(ierr);
1142         ierr = VecScatterCreate(vec1_B,msolv_ctx->is_B,msolv_ctx->sol_B,is_B_all,&msolv_ctx->correction_scatter_B);CHKERRQ(ierr);
1143         ierr = ISDestroy(&is_B_all);CHKERRQ(ierr);
1144         ierr = ISCreateGeneral(PetscObjectComm((PetscObject)is_A_all),n-n_v,idxs,PETSC_COPY_VALUES,&msolv_ctx->is_R);CHKERRQ(ierr);
1145         ierr = ISRestoreIndices(is_A_all,&idxs);CHKERRQ(ierr);
1146       }
1147       ierr = ISGetLocalSize(msolv_ctx->is_R,&n_R);CHKERRQ(ierr);
1148       ierr = MatCreateSeqAIJ(PETSC_COMM_SELF,n_R,n_R,0,NULL,&Afake);CHKERRQ(ierr);
1149       ierr = PCSetOperators(msolv_ctx->correction_solver,Afake,Afake);CHKERRQ(ierr);
1150       ierr = MatDestroy(&Afake);CHKERRQ(ierr);
1151       ierr = VecDestroy(&vec1_B);CHKERRQ(ierr);
1152 
1153       /* communicate benign info to solver context */
1154       if (benign_n) {
1155         PetscScalar *array;
1156 
1157         msolv_ctx->benign_n = benign_n;
1158         msolv_ctx->benign_zerodiag_subs = is_p_r;
1159         ierr = PetscMalloc1(benign_n,&msolv_ctx->benign_save_vals);CHKERRQ(ierr);
1160         msolv_ctx->benign_csAIB = cs_AIB_mat;
1161         ierr = MatCreateVecs(cs_AIB_mat,NULL,&msolv_ctx->benign_corr_work);CHKERRQ(ierr);
1162         ierr = VecGetArray(msolv_ctx->benign_corr_work,&array);CHKERRQ(ierr);
1163         ierr = VecCreateSeqWithArray(PETSC_COMM_SELF,1,size_schur,array,&msolv_ctx->benign_dummy_schur_vec);CHKERRQ(ierr);
1164         ierr = VecRestoreArray(msolv_ctx->benign_corr_work,&array);CHKERRQ(ierr);
1165         msolv_ctx->benign_AIIm1ones = benign_AIIm1_ones_mat;
1166       }
1167     }
1168     ierr = MatDestroy(&A);CHKERRQ(ierr);
1169     ierr = ISDestroy(&is_A_all);CHKERRQ(ierr);
1170 
1171     /* Work arrays */
1172     ierr = PetscMalloc2(max_subset_size,&dummy_idx,max_subset_size*max_subset_size,&work);CHKERRQ(ierr);
1173 
1174     /* matrices for adaptive selection */
1175     if (compute_Stilda) {
1176       if (!sub_schurs->sum_S_Ej_tilda_all) {
1177         ierr = MatCreate(PETSC_COMM_SELF,&sub_schurs->sum_S_Ej_tilda_all);CHKERRQ(ierr);
1178         ierr = MatSetSizes(sub_schurs->sum_S_Ej_tilda_all,PETSC_DECIDE,PETSC_DECIDE,size_active_schur,size_active_schur);CHKERRQ(ierr);
1179         ierr = MatSetType(sub_schurs->sum_S_Ej_tilda_all,MATAIJ);CHKERRQ(ierr);
1180         ierr = MatSeqAIJSetPreallocation(sub_schurs->sum_S_Ej_tilda_all,0,nnz);CHKERRQ(ierr);
1181       }
1182       if (!sub_schurs->sum_S_Ej_inv_all && deluxe) {
1183         ierr = MatCreate(PETSC_COMM_SELF,&sub_schurs->sum_S_Ej_inv_all);CHKERRQ(ierr);
1184         ierr = MatSetSizes(sub_schurs->sum_S_Ej_inv_all,PETSC_DECIDE,PETSC_DECIDE,size_active_schur,size_active_schur);CHKERRQ(ierr);
1185         ierr = MatSetType(sub_schurs->sum_S_Ej_inv_all,MATAIJ);CHKERRQ(ierr);
1186         ierr = MatSeqAIJSetPreallocation(sub_schurs->sum_S_Ej_inv_all,0,nnz);CHKERRQ(ierr);
1187       }
1188     }
1189 
1190     /* S_Ej_all */
1191     cum = cum2 = 0;
1192     ierr = MatDenseGetArray(S_all,&S_data);CHKERRQ(ierr);
1193     for (i=0;i<sub_schurs->n_subs;i++) {
1194       PetscInt j;
1195 
1196       /* get S_E */
1197       ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
1198       if (S_lower_triangular) { /* I need to expand the upper triangular data (column oriented) */
1199         PetscInt k;
1200         for (k=0;k<subset_size;k++) {
1201           for (j=k;j<subset_size;j++) {
1202             work[k*subset_size+j] = S_data[cum2+k*size_schur+j];
1203             work[j*subset_size+k] = PetscConj(S_data[cum2+k*size_schur+j]);
1204           }
1205         }
1206       } else { /* just copy to workspace */
1207         PetscInt k;
1208         for (k=0;k<subset_size;k++) {
1209           for (j=0;j<subset_size;j++) {
1210             work[k*subset_size+j] = S_data[cum2+k*size_schur+j];
1211           }
1212         }
1213       }
1214       /* insert S_E values */
1215       for (j=0;j<subset_size;j++) dummy_idx[j] = cum+j;
1216       if (sub_schurs->change) {
1217         Mat            change_sub,SEj,T;
1218         const PetscInt *idxs;
1219         PetscInt       nz;
1220 
1221         /* change basis */
1222         ierr = KSPGetOperators(sub_schurs->change[i],&change_sub,NULL);CHKERRQ(ierr);
1223         ierr = MatCreateSeqDense(PETSC_COMM_SELF,subset_size,subset_size,work,&SEj);CHKERRQ(ierr);
1224         if (!sub_schurs->change_with_qr) { /* currently there's no support for PtAP with P SeqAIJ */
1225           Mat T2;
1226           ierr = MatTransposeMatMult(change_sub,SEj,MAT_INITIAL_MATRIX,1.0,&T2);CHKERRQ(ierr);
1227           ierr = MatMatMult(T2,change_sub,MAT_INITIAL_MATRIX,1.0,&T);CHKERRQ(ierr);
1228           ierr = MatConvert(T,MATSEQDENSE,MAT_INPLACE_MATRIX,&T);CHKERRQ(ierr);
1229           ierr = MatDestroy(&T2);CHKERRQ(ierr);
1230         } else {
1231           ierr = MatPtAP(SEj,change_sub,MAT_INITIAL_MATRIX,1.0,&T);CHKERRQ(ierr);
1232         }
1233         ierr = MatCopy(T,SEj,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
1234         ierr = MatDestroy(&T);CHKERRQ(ierr);
1235         /* currently there's no support for ZeroRowsColumns with A dense */
1236         ierr = ISGetIndices(sub_schurs->change_primal_sub[i],&idxs);CHKERRQ(ierr);
1237         ierr = ISGetLocalSize(sub_schurs->change_primal_sub[i],&nz);CHKERRQ(ierr);
1238         for (j=0;j<nz;j++) {
1239           PetscInt k;
1240 
1241           ierr = PetscMemzero(work+subset_size*idxs[j],subset_size*sizeof(PetscScalar));CHKERRQ(ierr);
1242           for (k=0;k<subset_size;k++) work[idxs[j]+k*subset_size] = 0.;
1243           work[idxs[j]*(subset_size+1)] = 1.0;
1244         }
1245         ierr = ISRestoreIndices(sub_schurs->change_primal_sub[i],&idxs);CHKERRQ(ierr);
1246         ierr = MatDestroy(&SEj);CHKERRQ(ierr);
1247       }
1248       if (deluxe) {
1249         ierr = MatSetValues(sub_schurs->S_Ej_all,subset_size,dummy_idx,subset_size,dummy_idx,work,INSERT_VALUES);CHKERRQ(ierr);
1250         /* if adaptivity is requested, invert S_E blocks */
1251         if (compute_Stilda) {
1252           ierr = PetscBLASIntCast(subset_size,&B_N);CHKERRQ(ierr);
1253           ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
1254           if (!use_getr) { /* TODO add sytrf/i for symmetric non hermitian */
1255             PetscInt k;
1256             PetscStackCallBLAS("LAPACKpotrf",LAPACKpotrf_("L",&B_N,work,&B_N,&B_ierr));
1257             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRF Lapack routine %d",(int)B_ierr);
1258             PetscStackCallBLAS("LAPACKpotri",LAPACKpotri_("L",&B_N,work,&B_N,&B_ierr));
1259             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRI Lapack routine %d",(int)B_ierr);
1260             for (k=0;k<subset_size;k++) {
1261               for (j=k;j<subset_size;j++) {
1262                 work[j*subset_size+k] = work[k*subset_size+j];
1263               }
1264             }
1265           } else {
1266             PetscStackCallBLAS("LAPACKgetrf",LAPACKgetrf_(&B_N,&B_N,work,&B_N,pivots,&B_ierr));
1267             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRF Lapack routine %d",(int)B_ierr);
1268             PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,work,&B_N,pivots,Bwork,&B_lwork,&B_ierr));
1269             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRI Lapack routine %d",(int)B_ierr);
1270           }
1271           ierr = PetscFPTrapPop();CHKERRQ(ierr);
1272           ierr = MatSetValues(sub_schurs->sum_S_Ej_inv_all,subset_size,dummy_idx,subset_size,dummy_idx,work,INSERT_VALUES);CHKERRQ(ierr);
1273         }
1274       } else if (compute_Stilda) { /* not using deluxe */
1275         Mat         SEj;
1276         Vec         D;
1277         PetscScalar *array;
1278 
1279         ierr = MatCreateSeqDense(PETSC_COMM_SELF,subset_size,subset_size,work,&SEj);CHKERRQ(ierr);
1280         ierr = VecGetArray(Dall,&array);CHKERRQ(ierr);
1281         ierr = VecCreateSeqWithArray(PETSC_COMM_SELF,1,subset_size,array+cum,&D);CHKERRQ(ierr);
1282         ierr = VecRestoreArray(Dall,&array);CHKERRQ(ierr);
1283         ierr = MatDiagonalScale(SEj,D,D);CHKERRQ(ierr);
1284         ierr = MatDestroy(&SEj);CHKERRQ(ierr);
1285         ierr = VecDestroy(&D);CHKERRQ(ierr);
1286         ierr = MatSetValues(sub_schurs->S_Ej_all,subset_size,dummy_idx,subset_size,dummy_idx,work,INSERT_VALUES);CHKERRQ(ierr);
1287       }
1288       cum += subset_size;
1289       cum2 += subset_size*(size_schur + 1);
1290     }
1291     ierr = MatDenseRestoreArray(S_all,&S_data);CHKERRQ(ierr);
1292 
1293     if (solver_S) {
1294       ierr = MatFactorRestoreSchurComplement(F,&S_all);CHKERRQ(ierr);
1295     }
1296 
1297     schur_factor = NULL;
1298     if (compute_Stilda && size_active_schur) {
1299 
1300       if (sub_schurs->n_subs == 1 && size_schur == size_active_schur && deluxe) { /* we already computed the inverse */
1301         PetscInt j;
1302         for (j=0;j<size_schur;j++) dummy_idx[j] = j;
1303         ierr = MatSetValues(sub_schurs->sum_S_Ej_tilda_all,size_schur,dummy_idx,size_schur,dummy_idx,work,INSERT_VALUES);CHKERRQ(ierr);
1304       } else {
1305         Mat S_all_inv=NULL;
1306         if (solver_S) { /* use MatFactor calls to invert S */
1307             /* let MatFactor factor the Schur complement */
1308           ierr = MatFactorFactorizeSchurComplement(F);CHKERRQ(ierr);
1309           /* for adaptive selection we need S^-1; for solver reusage we need S_\Delta\Delta^-1.
1310              The latter is not the principal subminor for S^-1. However, the factors can be reused since S_\Delta\Delta is the leading principal submatrix of S */
1311           if (factor_workaround) {
1312             PetscScalar *data;
1313             PetscInt nd = 0;
1314 
1315             if (!sub_schurs->is_posdef) {
1316               SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Factor update not yet implemented for non SPD matrices");
1317             }
1318             ierr = MatFactorGetSchurComplement(F,&S_all_inv);CHKERRQ(ierr);
1319             ierr = MatDenseGetArray(S_all_inv,&data);CHKERRQ(ierr);
1320             if (sub_schurs->is_dir) { /* dirichlet dofs could have different scalings */
1321               ierr = ISGetLocalSize(sub_schurs->is_dir,&nd);CHKERRQ(ierr);
1322             }
1323             ierr = PetscMalloc1((size_active_schur*(size_active_schur+1))/2+nd,&schur_factor);CHKERRQ(ierr);
1324             cum = 0;
1325             for (i=0;i<size_active_schur;i++) {
1326               ierr = PetscMemcpy(schur_factor+cum,data+i*(size_schur+1),(size_active_schur-i)*sizeof(PetscScalar));CHKERRQ(ierr);
1327               cum += size_active_schur-i;
1328             }
1329             for (i=0;i<nd;i++) schur_factor[cum+i] = data[(i+size_active_schur)*(size_schur+1)];
1330             /* invert without calling MatFactorInvertSchurComplement, since we are hacking */
1331             ierr = PetscBLASIntCast(size_schur,&B_N);CHKERRQ(ierr);
1332             ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
1333             PetscStackCallBLAS("LAPACKpotri",LAPACKpotri_("L",&B_N,data,&B_N,&B_ierr));
1334             ierr = PetscFPTrapPop();CHKERRQ(ierr);
1335             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRI Lapack routine %d",(int)B_ierr);
1336             ierr = MatDenseRestoreArray(S_all_inv,&data);CHKERRQ(ierr);
1337           } else {
1338             ierr = MatFactorInvertSchurComplement(F);CHKERRQ(ierr);
1339             ierr = MatFactorGetSchurComplement(F,&S_all_inv);CHKERRQ(ierr);
1340           }
1341         } else { /* we need to invert explicitly since we are not using MatFactor for S */
1342           ierr = PetscObjectReference((PetscObject)S_all);CHKERRQ(ierr);
1343           S_all_inv = S_all;
1344           ierr = MatDenseGetArray(S_all_inv,&S_data);CHKERRQ(ierr);
1345           ierr = PetscBLASIntCast(size_schur,&B_N);CHKERRQ(ierr);
1346           ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
1347           if (!use_getr) { /* TODO add sytrf/i for symmetric non hermitian */
1348             PetscStackCallBLAS("LAPACKpotrf",LAPACKpotrf_("L",&B_N,S_data,&B_N,&B_ierr));
1349             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRF Lapack routine %d",(int)B_ierr);
1350             PetscStackCallBLAS("LAPACKpotri",LAPACKpotri_("L",&B_N,S_data,&B_N,&B_ierr));
1351             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRI Lapack routine %d",(int)B_ierr);
1352           } else {
1353             PetscStackCallBLAS("LAPACKgetrf",LAPACKgetrf_(&B_N,&B_N,S_data,&B_N,pivots,&B_ierr));
1354             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRF Lapack routine %d",(int)B_ierr);
1355             PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,S_data,&B_N,pivots,Bwork,&B_lwork,&B_ierr));
1356             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRI Lapack routine %d",(int)B_ierr);
1357           }
1358           ierr = PetscFPTrapPop();CHKERRQ(ierr);
1359           ierr = MatDenseRestoreArray(S_all_inv,&S_data);CHKERRQ(ierr);
1360         }
1361         /* S_Ej_tilda_all */
1362         cum = cum2 = 0;
1363         ierr = MatDenseGetArray(S_all_inv,&S_data);CHKERRQ(ierr);
1364         for (i=0;i<sub_schurs->n_subs;i++) {
1365           PetscInt j;
1366 
1367           ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
1368           /* get (St^-1)_E */
1369           /* Unless we are changing the variables, I don't need to expand to upper triangular since St^-1
1370              will be properly accessed later during adaptive selection */
1371           if (S_lower_triangular) {
1372             PetscInt k;
1373             if (sub_schurs->change) {
1374               for (k=0;k<subset_size;k++) {
1375                 for (j=k;j<subset_size;j++) {
1376                   work[k*subset_size+j] = S_data[cum2+k*size_schur+j];
1377                   work[j*subset_size+k] = work[k*subset_size+j];
1378                 }
1379               }
1380             } else {
1381               for (k=0;k<subset_size;k++) {
1382                 for (j=k;j<subset_size;j++) {
1383                   work[k*subset_size+j] = S_data[cum2+k*size_schur+j];
1384                 }
1385               }
1386             }
1387           } else {
1388             PetscInt k;
1389             for (k=0;k<subset_size;k++) {
1390               for (j=0;j<subset_size;j++) {
1391                 work[k*subset_size+j] = S_data[cum2+k*size_schur+j];
1392               }
1393             }
1394           }
1395           if (sub_schurs->change) {
1396             Mat change_sub,SEj,T;
1397 
1398             /* change basis */
1399             ierr = KSPGetOperators(sub_schurs->change[i],&change_sub,NULL);CHKERRQ(ierr);
1400             ierr = MatCreateSeqDense(PETSC_COMM_SELF,subset_size,subset_size,work,&SEj);CHKERRQ(ierr);
1401             if (!sub_schurs->change_with_qr) { /* currently there's no support for PtAP with P SeqAIJ */
1402               Mat T2;
1403               ierr = MatTransposeMatMult(change_sub,SEj,MAT_INITIAL_MATRIX,1.0,&T2);CHKERRQ(ierr);
1404               ierr = MatMatMult(T2,change_sub,MAT_INITIAL_MATRIX,1.0,&T);CHKERRQ(ierr);
1405               ierr = MatDestroy(&T2);CHKERRQ(ierr);
1406               ierr = MatConvert(T,MATSEQDENSE,MAT_INPLACE_MATRIX,&T);CHKERRQ(ierr);
1407             } else {
1408               ierr = MatPtAP(SEj,change_sub,MAT_INITIAL_MATRIX,1.0,&T);CHKERRQ(ierr);
1409             }
1410             ierr = MatCopy(T,SEj,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
1411             ierr = MatDestroy(&T);CHKERRQ(ierr);
1412             /* set diagonal entry to a very large value to pick the basis we are eliminating as the first eigenvectors with adaptive selection */
1413             {
1414               const PetscInt *idxs;
1415               PetscInt n,j;
1416               ierr = ISGetLocalSize(sub_schurs->change_primal_sub[i],&n);CHKERRQ(ierr);
1417               ierr = ISGetIndices(sub_schurs->change_primal_sub[i],&idxs);CHKERRQ(ierr);
1418               for (j=0;j<n;j++) {
1419                 PetscInt k;
1420                 for (k=0;k<subset_size;k++) {
1421                   work[k+idxs[j]*subset_size] = work[idxs[j]+k*subset_size] = 0.;
1422                 }
1423                 work[idxs[j] + idxs[j]*subset_size] = 1./PETSC_SMALL;
1424               }
1425               ierr = ISRestoreIndices(sub_schurs->change_primal_sub[i],&idxs);CHKERRQ(ierr);
1426             }
1427             ierr = MatDestroy(&SEj);CHKERRQ(ierr);
1428           }
1429           for (j=0;j<subset_size;j++) dummy_idx[j] = cum+j;
1430           ierr = MatSetValues(sub_schurs->sum_S_Ej_tilda_all,subset_size,dummy_idx,subset_size,dummy_idx,work,INSERT_VALUES);CHKERRQ(ierr);
1431           cum += subset_size;
1432           cum2 += subset_size*(size_schur + 1);
1433         }
1434         ierr = MatDenseRestoreArray(S_all_inv,&S_data);CHKERRQ(ierr);
1435         if (solver_S) {
1436           ierr = MatFactorRestoreSchurComplement(F,&S_all_inv);CHKERRQ(ierr);
1437         }
1438         ierr = MatDestroy(&S_all_inv);CHKERRQ(ierr);
1439       }
1440 
1441       /* move back factors to Schur data into F */
1442       if (factor_workaround) {
1443         Mat S_tmp;
1444         PetscInt nv,nd=0;
1445 
1446         if (!solver_S) {
1447           SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"This should not happen");
1448         }
1449         ierr = ISGetLocalSize(sub_schurs->is_vertices,&nv);CHKERRQ(ierr);
1450         ierr = MatFactorGetSchurComplement(F,&S_tmp);CHKERRQ(ierr);
1451         if (sub_schurs->is_posdef) {
1452           PetscScalar *data;
1453 
1454           ierr = MatZeroEntries(S_tmp);CHKERRQ(ierr);
1455           ierr = MatDenseGetArray(S_tmp,&data);CHKERRQ(ierr);
1456 
1457           if (S_lower_triangular) {
1458             cum = 0;
1459             for (i=0;i<size_active_schur;i++) {
1460               ierr = PetscMemcpy(data+i*(size_schur+1),schur_factor+cum,(size_active_schur-i)*sizeof(PetscScalar));CHKERRQ(ierr);
1461               cum += size_active_schur-i;
1462 	    }
1463           } else {
1464             ierr = PetscMemcpy(data,schur_factor,size_schur*size_schur*sizeof(PetscScalar));CHKERRQ(ierr);
1465           }
1466           if (sub_schurs->is_dir) {
1467             ierr = ISGetLocalSize(sub_schurs->is_dir,&nd);CHKERRQ(ierr);
1468 	    for (i=0;i<nd;i++) {
1469 	      data[(i+size_active_schur)*(size_schur+1)] = schur_factor[cum+i];
1470 	    }
1471           }
1472           /* workaround: since I cannot modify the matrices used inside the solvers for the forward and backward substitutions,
1473              set the diagonal entry of the Schur factor to a very large value */
1474           for (i=size_active_schur+nd;i<size_schur;i++) {
1475             data[i*(size_schur+1)] = infty;
1476           }
1477           ierr = MatDenseRestoreArray(S_tmp,&data);CHKERRQ(ierr);
1478         } else {
1479           SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Factor update not yet implemented for non SPD matrices");
1480         }
1481         ierr = MatFactorRestoreSchurComplement(F,&S_tmp);CHKERRQ(ierr);
1482       }
1483     } else if (factor_workaround) { /* we need to eliminate any unneeded coupling */
1484       PetscScalar *data;
1485       PetscInt    nd = 0;
1486 
1487       if (sub_schurs->is_dir) { /* dirichlet dofs could have different scalings */
1488         ierr = ISGetLocalSize(sub_schurs->is_dir,&nd);CHKERRQ(ierr);
1489       }
1490       ierr = MatFactorGetSchurComplement(F,&S_all);CHKERRQ(ierr);
1491       ierr = MatDenseGetArray(S_all,&data);CHKERRQ(ierr);
1492       for (i=0;i<size_active_schur;i++) {
1493         ierr = PetscMemzero(data+i*size_schur+size_active_schur,(size_schur-size_active_schur)*sizeof(PetscScalar));CHKERRQ(ierr);
1494       }
1495       for (i=size_active_schur+nd;i<size_schur;i++) {
1496         ierr = PetscMemzero(data+i*size_schur+size_active_schur,(size_schur-size_active_schur)*sizeof(PetscScalar));CHKERRQ(ierr);
1497         data[i*(size_schur+1)] = infty;
1498       }
1499       ierr = MatDenseRestoreArray(S_all,&data);CHKERRQ(ierr);
1500       ierr = MatFactorRestoreSchurComplement(F,&S_all);CHKERRQ(ierr);
1501     }
1502     ierr = PetscFree2(dummy_idx,work);CHKERRQ(ierr);
1503     ierr = PetscFree(schur_factor);CHKERRQ(ierr);
1504     ierr = VecDestroy(&Dall);CHKERRQ(ierr);
1505   }
1506   ierr = PetscFree(nnz);CHKERRQ(ierr);
1507   ierr = MatDestroy(&F);CHKERRQ(ierr);
1508   ierr = ISDestroy(&is_I_layer);CHKERRQ(ierr);
1509   ierr = MatDestroy(&S_all);CHKERRQ(ierr);
1510   ierr = MatDestroy(&A_BB);CHKERRQ(ierr);
1511   ierr = MatDestroy(&A_IB);CHKERRQ(ierr);
1512   ierr = MatDestroy(&A_BI);CHKERRQ(ierr);
1513   ierr = MatAssemblyBegin(sub_schurs->S_Ej_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1514   ierr = MatAssemblyEnd(sub_schurs->S_Ej_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1515   if (compute_Stilda) {
1516     ierr = MatAssemblyBegin(sub_schurs->sum_S_Ej_tilda_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1517     ierr = MatAssemblyEnd(sub_schurs->sum_S_Ej_tilda_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1518     if (deluxe) {
1519       ierr = MatAssemblyBegin(sub_schurs->sum_S_Ej_inv_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1520       ierr = MatAssemblyEnd(sub_schurs->sum_S_Ej_inv_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1521     }
1522   }
1523 
1524   /* Global matrix of all assembled Schur on subsets */
1525   ierr = MatISSetLocalMat(work_mat,sub_schurs->S_Ej_all);CHKERRQ(ierr);
1526   ierr = MatISSetMPIXAIJPreallocation_Private(work_mat,global_schur_subsets,PETSC_TRUE);CHKERRQ(ierr);
1527   ierr = MatISGetMPIXAIJ(work_mat,MAT_REUSE_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
1528 
1529   /* Get local part of (\sum_j S_Ej) */
1530   if (!sub_schurs->sum_S_Ej_all) {
1531     ierr = MatGetSubMatrices(global_schur_subsets,1,&all_subsets_n,&all_subsets_n,MAT_INITIAL_MATRIX,&submats);CHKERRQ(ierr);
1532     sub_schurs->sum_S_Ej_all = submats[0];
1533   } else {
1534     ierr = PetscMalloc1(1,&submats);CHKERRQ(ierr);
1535     submats[0] = sub_schurs->sum_S_Ej_all;
1536     ierr = MatGetSubMatrices(global_schur_subsets,1,&all_subsets_n,&all_subsets_n,MAT_REUSE_MATRIX,&submats);CHKERRQ(ierr);
1537   }
1538 
1539   /* Get local part of (\sum_j S^-1_Ej) (\sum_j St^-1_Ej) */
1540   if (compute_Stilda) {
1541     ierr = MatISSetLocalMat(work_mat,sub_schurs->sum_S_Ej_tilda_all);CHKERRQ(ierr);
1542     ierr = MatISGetMPIXAIJ(work_mat,MAT_REUSE_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
1543     submats[0] = sub_schurs->sum_S_Ej_tilda_all;
1544     ierr = MatGetSubMatrices(global_schur_subsets,1,&all_subsets_n,&all_subsets_n,MAT_REUSE_MATRIX,&submats);CHKERRQ(ierr);
1545     if (deluxe) {
1546       ierr = MatISSetLocalMat(work_mat,sub_schurs->sum_S_Ej_inv_all);CHKERRQ(ierr);
1547       ierr = MatISGetMPIXAIJ(work_mat,MAT_REUSE_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
1548       submats[0] = sub_schurs->sum_S_Ej_inv_all;
1549       ierr = MatGetSubMatrices(global_schur_subsets,1,&all_subsets_n,&all_subsets_n,MAT_REUSE_MATRIX,&submats);CHKERRQ(ierr);
1550     } else {
1551       PetscScalar *array;
1552       PetscInt    cum;
1553 
1554       ierr = MatSeqAIJGetArray(sub_schurs->sum_S_Ej_tilda_all,&array);CHKERRQ(ierr);
1555       cum = 0;
1556       for (i=0;i<sub_schurs->n_subs;i++) {
1557         ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
1558         ierr = PetscBLASIntCast(subset_size,&B_N);CHKERRQ(ierr);
1559         ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
1560         PetscStackCallBLAS("LAPACKpotrf",LAPACKpotrf_("L",&B_N,array+cum,&B_N,&B_ierr));
1561         if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRF Lapack routine %d",(int)B_ierr);
1562         PetscStackCallBLAS("LAPACKpotri",LAPACKpotri_("L",&B_N,array+cum,&B_N,&B_ierr));
1563         if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRI Lapack routine %d",(int)B_ierr);
1564         ierr = PetscFPTrapPop();CHKERRQ(ierr);
1565         cum += subset_size*subset_size;
1566       }
1567       ierr = MatSeqAIJRestoreArray(sub_schurs->sum_S_Ej_tilda_all,&array);CHKERRQ(ierr);
1568       ierr = PetscObjectReference((PetscObject)sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
1569       ierr = MatDestroy(&sub_schurs->sum_S_Ej_inv_all);CHKERRQ(ierr);
1570       sub_schurs->sum_S_Ej_inv_all = sub_schurs->sum_S_Ej_all;
1571     }
1572   }
1573 
1574   /* free workspace */
1575   ierr = PetscFree(submats);CHKERRQ(ierr);
1576   ierr = PetscFree2(Bwork,pivots);CHKERRQ(ierr);
1577   ierr = MatDestroy(&global_schur_subsets);CHKERRQ(ierr);
1578   ierr = MatDestroy(&work_mat);CHKERRQ(ierr);
1579   ierr = ISDestroy(&all_subsets_n);CHKERRQ(ierr);
1580   ierr = PetscCommDestroy(&comm_n);CHKERRQ(ierr);
1581   PetscFunctionReturn(0);
1582 }
1583 
1584 #undef __FUNCT__
1585 #define __FUNCT__ "PCBDDCSubSchursInit"
1586 PetscErrorCode PCBDDCSubSchursInit(PCBDDCSubSchurs sub_schurs, IS is_I, IS is_B, PCBDDCGraph graph, ISLocalToGlobalMapping BtoNmap)
1587 {
1588   IS              *faces,*edges,*all_cc,vertices;
1589   PetscInt        i,n_faces,n_edges,n_all_cc;
1590   PetscBool       is_sorted;
1591   PetscErrorCode  ierr;
1592 
1593   PetscFunctionBegin;
1594   ierr = ISSorted(is_I,&is_sorted);CHKERRQ(ierr);
1595   if (!is_sorted) SETERRQ(PetscObjectComm((PetscObject)is_I),PETSC_ERR_PLIB,"IS for I dofs should be shorted");
1596   ierr = ISSorted(is_B,&is_sorted);CHKERRQ(ierr);
1597   if (!is_sorted) SETERRQ(PetscObjectComm((PetscObject)is_B),PETSC_ERR_PLIB,"IS for B dofs should be shorted");
1598 
1599   /* reset any previous data */
1600   ierr = PCBDDCSubSchursReset(sub_schurs);CHKERRQ(ierr);
1601 
1602   /* get index sets for faces and edges (already sorted by global ordering) */
1603   ierr = PCBDDCGraphGetCandidatesIS(graph,&n_faces,&faces,&n_edges,&edges,&vertices);CHKERRQ(ierr);
1604   n_all_cc = n_faces+n_edges;
1605   ierr = PetscBTCreate(n_all_cc,&sub_schurs->is_edge);CHKERRQ(ierr);
1606   ierr = PetscMalloc1(n_all_cc,&all_cc);CHKERRQ(ierr);
1607   for (i=0;i<n_faces;i++) {
1608     all_cc[i] = faces[i];
1609   }
1610   for (i=0;i<n_edges;i++) {
1611     all_cc[n_faces+i] = edges[i];
1612     ierr = PetscBTSet(sub_schurs->is_edge,n_faces+i);CHKERRQ(ierr);
1613   }
1614   ierr = PetscFree(faces);CHKERRQ(ierr);
1615   ierr = PetscFree(edges);CHKERRQ(ierr);
1616   sub_schurs->is_dir = NULL;
1617   ierr = PCBDDCGraphGetDirichletDofsB(graph,&sub_schurs->is_dir);CHKERRQ(ierr);
1618 
1619   /* Determine if MatFactor can be used */
1620   sub_schurs->schur_explicit = PETSC_FALSE;
1621 #if defined(PETSC_HAVE_MUMPS)
1622   sub_schurs->schur_explicit = PETSC_TRUE;
1623 #endif
1624 #if defined(PETSC_HAVE_MKL_PARDISO)
1625   sub_schurs->schur_explicit = PETSC_TRUE;
1626 #endif
1627 
1628   ierr = PetscObjectReference((PetscObject)is_I);CHKERRQ(ierr);
1629   sub_schurs->is_I = is_I;
1630   ierr = PetscObjectReference((PetscObject)is_B);CHKERRQ(ierr);
1631   sub_schurs->is_B = is_B;
1632   ierr = PetscObjectReference((PetscObject)graph->l2gmap);CHKERRQ(ierr);
1633   sub_schurs->l2gmap = graph->l2gmap;
1634   ierr = PetscObjectReference((PetscObject)BtoNmap);CHKERRQ(ierr);
1635   sub_schurs->BtoNmap = BtoNmap;
1636   sub_schurs->n_subs = n_all_cc;
1637   sub_schurs->is_subs = all_cc;
1638   if (!sub_schurs->schur_explicit) { /* sort by local ordering if we are not using MatFactor */
1639     for (i=0;i<sub_schurs->n_subs;i++) {
1640       ierr = ISSort(sub_schurs->is_subs[i]);CHKERRQ(ierr);
1641     }
1642   }
1643   sub_schurs->is_vertices = vertices;
1644   sub_schurs->S_Ej_all = NULL;
1645   sub_schurs->sum_S_Ej_all = NULL;
1646   sub_schurs->sum_S_Ej_inv_all = NULL;
1647   sub_schurs->sum_S_Ej_tilda_all = NULL;
1648   sub_schurs->is_Ej_all = NULL;
1649   PetscFunctionReturn(0);
1650 }
1651 
1652 #undef __FUNCT__
1653 #define __FUNCT__ "PCBDDCSubSchursCreate"
1654 PetscErrorCode PCBDDCSubSchursCreate(PCBDDCSubSchurs *sub_schurs)
1655 {
1656   PCBDDCSubSchurs schurs_ctx;
1657   PetscErrorCode  ierr;
1658 
1659   PetscFunctionBegin;
1660   ierr = PetscNew(&schurs_ctx);CHKERRQ(ierr);
1661   schurs_ctx->n_subs = 0;
1662   *sub_schurs = schurs_ctx;
1663   PetscFunctionReturn(0);
1664 }
1665 
1666 #undef __FUNCT__
1667 #define __FUNCT__ "PCBDDCSubSchursReset"
1668 PetscErrorCode PCBDDCSubSchursReset(PCBDDCSubSchurs sub_schurs)
1669 {
1670   PetscInt       i;
1671   PetscErrorCode ierr;
1672 
1673   PetscFunctionBegin;
1674   ierr = MatDestroy(&sub_schurs->A);CHKERRQ(ierr);
1675   ierr = MatDestroy(&sub_schurs->S);CHKERRQ(ierr);
1676   ierr = ISDestroy(&sub_schurs->is_I);CHKERRQ(ierr);
1677   ierr = ISDestroy(&sub_schurs->is_B);CHKERRQ(ierr);
1678   ierr = ISLocalToGlobalMappingDestroy(&sub_schurs->l2gmap);CHKERRQ(ierr);
1679   ierr = ISLocalToGlobalMappingDestroy(&sub_schurs->BtoNmap);CHKERRQ(ierr);
1680   ierr = MatDestroy(&sub_schurs->S_Ej_all);CHKERRQ(ierr);
1681   ierr = MatDestroy(&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
1682   ierr = MatDestroy(&sub_schurs->sum_S_Ej_inv_all);CHKERRQ(ierr);
1683   ierr = MatDestroy(&sub_schurs->sum_S_Ej_tilda_all);CHKERRQ(ierr);
1684   ierr = ISDestroy(&sub_schurs->is_Ej_all);CHKERRQ(ierr);
1685   ierr = ISDestroy(&sub_schurs->is_vertices);CHKERRQ(ierr);
1686   ierr = ISDestroy(&sub_schurs->is_dir);CHKERRQ(ierr);
1687   ierr = PetscBTDestroy(&sub_schurs->is_edge);CHKERRQ(ierr);
1688   for (i=0;i<sub_schurs->n_subs;i++) {
1689     ierr = ISDestroy(&sub_schurs->is_subs[i]);CHKERRQ(ierr);
1690   }
1691   if (sub_schurs->n_subs) {
1692     ierr = PetscFree(sub_schurs->is_subs);CHKERRQ(ierr);
1693   }
1694   if (sub_schurs->reuse_solver) {
1695     ierr = PCBDDCReuseSolversReset(sub_schurs->reuse_solver);CHKERRQ(ierr);
1696   }
1697   ierr = PetscFree(sub_schurs->reuse_solver);CHKERRQ(ierr);
1698   if (sub_schurs->change) {
1699     for (i=0;i<sub_schurs->n_subs;i++) {
1700       ierr = KSPDestroy(&sub_schurs->change[i]);CHKERRQ(ierr);
1701       ierr = ISDestroy(&sub_schurs->change_primal_sub[i]);CHKERRQ(ierr);
1702     }
1703   }
1704   ierr = PetscFree(sub_schurs->change);CHKERRQ(ierr);
1705   ierr = PetscFree(sub_schurs->change_primal_sub);CHKERRQ(ierr);
1706   sub_schurs->n_subs = 0;
1707   PetscFunctionReturn(0);
1708 }
1709 
1710 #undef __FUNCT__
1711 #define __FUNCT__ "PCBDDCAdjGetNextLayer_Private"
1712 PETSC_STATIC_INLINE PetscErrorCode PCBDDCAdjGetNextLayer_Private(PetscInt* queue_tip,PetscInt n_prev,PetscBT touched,PetscInt* xadj,PetscInt* adjncy,PetscInt* n_added)
1713 {
1714   PetscInt       i,j,n;
1715   PetscErrorCode ierr;
1716 
1717   PetscFunctionBegin;
1718   n = 0;
1719   for (i=-n_prev;i<0;i++) {
1720     PetscInt start_dof = queue_tip[i];
1721     for (j=xadj[start_dof];j<xadj[start_dof+1];j++) {
1722       PetscInt dof = adjncy[j];
1723       if (!PetscBTLookup(touched,dof)) {
1724         ierr = PetscBTSet(touched,dof);CHKERRQ(ierr);
1725         queue_tip[n] = dof;
1726         n++;
1727       }
1728     }
1729   }
1730   *n_added = n;
1731   PetscFunctionReturn(0);
1732 }
1733