xref: /petsc/src/ksp/pc/impls/bddc/bddcschurs.c (revision 04270d10403b2d22cab08fba741a972f7ff8fba2)
1 #include <../src/ksp/pc/impls/bddc/bddc.h>
2 #include <../src/ksp/pc/impls/bddc/bddcprivate.h>
3 #include <petscblaslapack.h>
4 
5 /* this is declared in dense.h */
6 PETSC_INTERN PetscErrorCode MatSeqDenseInvertFactors_Private(Mat);
7 PETSC_STATIC_INLINE PetscErrorCode PCBDDCAdjGetNextLayer_Private(PetscInt*,PetscInt,PetscBT,PetscInt*,PetscInt*,PetscInt*);
8 static PetscErrorCode PCBDDCComputeExplicitSchur(Mat,PetscBool,MatReuse,Mat*);
9 static PetscErrorCode PCBDDCReuseSolvers_Interior(PC,Vec,Vec);
10 static PetscErrorCode PCBDDCReuseSolvers_Correction(PC,Vec,Vec);
11 
12 /* if v2 is not present, correction is done in-place */
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,&size_schur,NULL);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 = MatMultTranspose(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 #if defined(PETSC_USE_COMPLEX)
59       sum = -(PetscRealPart(sum)/nz + PETSC_i*(PetscImaginaryPart(sum)/nz));
60 #else
61       sum = -sum/nz;
62 #endif
63       for (i=0;i<nz-1;i++) array2[cols[i]] += sum;
64       ctx->benign_save_vals[n] = array2[cols[nz-1]];
65       array2[cols[nz-1]] = sum;
66       ierr = ISRestoreIndices(ctx->benign_zerodiag_subs[n],&cols);CHKERRQ(ierr);
67     }
68   } else {
69     PetscInt n;
70     for (n=0;n<ctx->benign_n;n++) {
71       PetscScalar    sum = 0.;
72       const PetscInt *cols;
73       PetscInt       nz,i;
74       ierr = ISGetLocalSize(ctx->benign_zerodiag_subs[n],&nz);CHKERRQ(ierr);
75       ierr = ISGetIndices(ctx->benign_zerodiag_subs[n],&cols);CHKERRQ(ierr);
76       for (i=0;i<nz-1;i++) sum += array[cols[i]];
77 #if defined(PETSC_USE_COMPLEX)
78       sum = -(PetscRealPart(sum)/nz + PETSC_i*(PetscImaginaryPart(sum)/nz));
79 #else
80       sum = -sum/nz;
81 #endif
82       for (i=0;i<nz-1;i++) array2[cols[i]] += sum;
83       array2[cols[nz-1]] = ctx->benign_save_vals[n];
84       ierr = ISRestoreIndices(ctx->benign_zerodiag_subs[n],&cols);CHKERRQ(ierr);
85     }
86   }
87   if (v2) {
88     ierr = VecRestoreArrayRead(v,(const PetscScalar**)&array);CHKERRQ(ierr);
89     ierr = VecRestoreArray(v2,&array2);CHKERRQ(ierr);
90   } else {
91     ierr = VecRestoreArray(v,&array);CHKERRQ(ierr);
92   }
93   if (!sol && full) {
94     Vec      usedv;
95     PetscInt n_I,size_schur;
96 
97     /* get sizes */
98     ierr = MatGetSize(ctx->benign_csAIB,&size_schur,NULL);CHKERRQ(ierr);
99     ierr = VecGetSize(v,&n_I);CHKERRQ(ierr);
100     n_I = n_I - size_schur;
101     /* compute schur rhs correction */
102     if (v2) {
103       usedv = v2;
104     } else {
105       usedv = v;
106     }
107     /* apply schur rhs correction */
108     ierr = MatMultTranspose(ctx->benign_AIIm1ones,usedv,ctx->benign_corr_work);CHKERRQ(ierr);
109     ierr = VecGetArrayRead(usedv,(const PetscScalar**)&array);CHKERRQ(ierr);
110     ierr = VecPlaceArray(ctx->benign_dummy_schur_vec,array+n_I);CHKERRQ(ierr);
111     ierr = VecRestoreArrayRead(usedv,(const PetscScalar**)&array);CHKERRQ(ierr);
112     ierr = MatMultAdd(ctx->benign_csAIB,ctx->benign_corr_work,ctx->benign_dummy_schur_vec,ctx->benign_dummy_schur_vec);CHKERRQ(ierr);
113     ierr = VecResetArray(ctx->benign_dummy_schur_vec);CHKERRQ(ierr);
114   }
115   PetscFunctionReturn(0);
116 }
117 
118 static PetscErrorCode PCBDDCReuseSolvers_Solve_Private(PC pc, Vec rhs, Vec sol, PetscBool transpose, PetscBool full)
119 {
120   PCBDDCReuseSolvers ctx;
121   PetscBool          copy = PETSC_FALSE;
122   PetscErrorCode     ierr;
123 
124   PetscFunctionBegin;
125   ierr = PCShellGetContext(pc,(void **)&ctx);CHKERRQ(ierr);
126   if (full) {
127 #if defined(PETSC_HAVE_MUMPS)
128     ierr = MatMumpsSetIcntl(ctx->F,26,-1);CHKERRQ(ierr);
129 #endif
130 #if defined(PETSC_HAVE_MKL_PARDISO)
131     ierr = MatMkl_PardisoSetCntl(ctx->F,70,0);CHKERRQ(ierr);
132 #endif
133     copy = ctx->has_vertices;
134   } else { /* interior solver */
135 #if defined(PETSC_HAVE_MUMPS)
136     ierr = MatMumpsSetIcntl(ctx->F,26,0);CHKERRQ(ierr);
137 #endif
138 #if defined(PETSC_HAVE_MKL_PARDISO)
139     ierr = MatMkl_PardisoSetCntl(ctx->F,70,1);CHKERRQ(ierr);
140 #endif
141     copy = PETSC_TRUE;
142   }
143   /* copy rhs into factored matrix workspace */
144   if (copy) {
145     PetscInt    n;
146     PetscScalar *array,*array_solver;
147 
148     ierr = VecGetLocalSize(rhs,&n);CHKERRQ(ierr);
149     ierr = VecGetArrayRead(rhs,(const PetscScalar**)&array);CHKERRQ(ierr);
150     ierr = VecGetArray(ctx->rhs,&array_solver);CHKERRQ(ierr);
151     ierr = PetscMemcpy(array_solver,array,n*sizeof(PetscScalar));CHKERRQ(ierr);
152     ierr = VecRestoreArray(ctx->rhs,&array_solver);CHKERRQ(ierr);
153     ierr = VecRestoreArrayRead(rhs,(const PetscScalar**)&array);CHKERRQ(ierr);
154 
155     ierr = PCBDDCReuseSolversBenignAdapt(ctx,ctx->rhs,NULL,PETSC_FALSE,full);CHKERRQ(ierr);
156     if (transpose) {
157       ierr = MatSolveTranspose(ctx->F,ctx->rhs,ctx->sol);CHKERRQ(ierr);
158     } else {
159       ierr = MatSolve(ctx->F,ctx->rhs,ctx->sol);CHKERRQ(ierr);
160     }
161     ierr = PCBDDCReuseSolversBenignAdapt(ctx,ctx->sol,NULL,PETSC_TRUE,full);CHKERRQ(ierr);
162 
163     /* get back data to caller worskpace */
164     ierr = VecGetArrayRead(ctx->sol,(const PetscScalar**)&array_solver);CHKERRQ(ierr);
165     ierr = VecGetArray(sol,&array);CHKERRQ(ierr);
166     ierr = PetscMemcpy(array,array_solver,n*sizeof(PetscScalar));CHKERRQ(ierr);
167     ierr = VecRestoreArray(sol,&array);CHKERRQ(ierr);
168     ierr = VecRestoreArrayRead(ctx->sol,(const PetscScalar**)&array_solver);CHKERRQ(ierr);
169   } else {
170     if (ctx->benign_n) {
171       ierr = PCBDDCReuseSolversBenignAdapt(ctx,rhs,ctx->rhs,PETSC_FALSE,full);CHKERRQ(ierr);
172       if (transpose) {
173         ierr = MatSolveTranspose(ctx->F,ctx->rhs,sol);CHKERRQ(ierr);
174       } else {
175         ierr = MatSolve(ctx->F,ctx->rhs,sol);CHKERRQ(ierr);
176       }
177       ierr = PCBDDCReuseSolversBenignAdapt(ctx,sol,NULL,PETSC_TRUE,full);CHKERRQ(ierr);
178     } else {
179       if (transpose) {
180         ierr = MatSolveTranspose(ctx->F,rhs,sol);CHKERRQ(ierr);
181       } else {
182         ierr = MatSolve(ctx->F,rhs,sol);CHKERRQ(ierr);
183       }
184     }
185   }
186   /* restore defaults */
187 #if defined(PETSC_HAVE_MUMPS)
188   ierr = MatMumpsSetIcntl(ctx->F,26,-1);CHKERRQ(ierr);
189 #endif
190 #if defined(PETSC_HAVE_MKL_PARDISO)
191   ierr = MatMkl_PardisoSetCntl(ctx->F,70,0);CHKERRQ(ierr);
192 #endif
193   PetscFunctionReturn(0);
194 }
195 
196 static PetscErrorCode PCBDDCReuseSolvers_Correction(PC pc, Vec rhs, Vec sol)
197 {
198   PetscErrorCode   ierr;
199 
200   PetscFunctionBegin;
201   ierr = PCBDDCReuseSolvers_Solve_Private(pc,rhs,sol,PETSC_FALSE,PETSC_TRUE);CHKERRQ(ierr);
202   PetscFunctionReturn(0);
203 }
204 
205 static PetscErrorCode PCBDDCReuseSolvers_CorrectionTranspose(PC pc, Vec rhs, Vec sol)
206 {
207   PetscErrorCode   ierr;
208 
209   PetscFunctionBegin;
210   ierr = PCBDDCReuseSolvers_Solve_Private(pc,rhs,sol,PETSC_TRUE,PETSC_TRUE);CHKERRQ(ierr);
211   PetscFunctionReturn(0);
212 }
213 
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 static PetscErrorCode PCBDDCReuseSolvers_InteriorTranspose(PC pc, Vec rhs, Vec sol)
224 {
225   PetscErrorCode   ierr;
226 
227   PetscFunctionBegin;
228   ierr = PCBDDCReuseSolvers_Solve_Private(pc,rhs,sol,PETSC_TRUE,PETSC_FALSE);CHKERRQ(ierr);
229   PetscFunctionReturn(0);
230 }
231 
232 static PetscErrorCode PCBDDCReuseSolversReset(PCBDDCReuseSolvers reuse)
233 {
234   PetscInt       i;
235   PetscErrorCode ierr;
236 
237   PetscFunctionBegin;
238   ierr = MatDestroy(&reuse->F);CHKERRQ(ierr);
239   ierr = VecDestroy(&reuse->sol);CHKERRQ(ierr);
240   ierr = VecDestroy(&reuse->rhs);CHKERRQ(ierr);
241   ierr = PCDestroy(&reuse->interior_solver);CHKERRQ(ierr);
242   ierr = PCDestroy(&reuse->correction_solver);CHKERRQ(ierr);
243   ierr = ISDestroy(&reuse->is_R);CHKERRQ(ierr);
244   ierr = ISDestroy(&reuse->is_B);CHKERRQ(ierr);
245   ierr = VecScatterDestroy(&reuse->correction_scatter_B);CHKERRQ(ierr);
246   ierr = VecDestroy(&reuse->sol_B);CHKERRQ(ierr);
247   ierr = VecDestroy(&reuse->rhs_B);CHKERRQ(ierr);
248   for (i=0;i<reuse->benign_n;i++) {
249     ierr = ISDestroy(&reuse->benign_zerodiag_subs[i]);CHKERRQ(ierr);
250   }
251   ierr = PetscFree(reuse->benign_zerodiag_subs);CHKERRQ(ierr);
252   ierr = PetscFree(reuse->benign_save_vals);CHKERRQ(ierr);
253   ierr = MatDestroy(&reuse->benign_csAIB);CHKERRQ(ierr);
254   ierr = MatDestroy(&reuse->benign_AIIm1ones);CHKERRQ(ierr);
255   ierr = VecDestroy(&reuse->benign_corr_work);CHKERRQ(ierr);
256   ierr = VecDestroy(&reuse->benign_dummy_schur_vec);CHKERRQ(ierr);
257   PetscFunctionReturn(0);
258 }
259 
260 static PetscErrorCode PCBDDCComputeExplicitSchur(Mat M, PetscBool issym, MatReuse reuse, Mat *S)
261 {
262   Mat            B, C, D, Bd, Cd, AinvBd;
263   KSP            ksp;
264   PC             pc;
265   PetscBool      isLU, isILU, isCHOL, Bdense, Cdense;
266   PetscReal      fill = 2.0;
267   PetscInt       n_I;
268   PetscMPIInt    size;
269   PetscErrorCode ierr;
270 
271   PetscFunctionBegin;
272   ierr = MPI_Comm_size(PetscObjectComm((PetscObject)M),&size);CHKERRQ(ierr);
273   if (size != 1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Not for parallel matrices");
274   if (reuse == MAT_REUSE_MATRIX) {
275     PetscBool Sdense;
276 
277     ierr = PetscObjectTypeCompare((PetscObject)*S, MATSEQDENSE, &Sdense);CHKERRQ(ierr);
278     if (!Sdense) SETERRQ(PetscObjectComm((PetscObject)M),PETSC_ERR_SUP,"S should dense");
279   }
280   ierr = MatSchurComplementGetSubMatrices(M, NULL, NULL, &B, &C, &D);CHKERRQ(ierr);
281   ierr = MatSchurComplementGetKSP(M, &ksp);CHKERRQ(ierr);
282   ierr = KSPGetPC(ksp, &pc);CHKERRQ(ierr);
283   ierr = PetscObjectTypeCompare((PetscObject) pc, PCLU, &isLU);CHKERRQ(ierr);
284   ierr = PetscObjectTypeCompare((PetscObject) pc, PCILU, &isILU);CHKERRQ(ierr);
285   ierr = PetscObjectTypeCompare((PetscObject) pc, PCCHOLESKY, &isCHOL);CHKERRQ(ierr);
286   ierr = PetscObjectTypeCompare((PetscObject) B, MATSEQDENSE, &Bdense);CHKERRQ(ierr);
287   ierr = PetscObjectTypeCompare((PetscObject) C, MATSEQDENSE, &Cdense);CHKERRQ(ierr);
288   ierr = MatGetSize(B,&n_I,NULL);CHKERRQ(ierr);
289   if (n_I) {
290     if (!Bdense) {
291       ierr = MatConvert(B, MATSEQDENSE, MAT_INITIAL_MATRIX, &Bd);CHKERRQ(ierr);
292     } else {
293       Bd = B;
294     }
295 
296     if (isLU || isILU || isCHOL) {
297       Mat fact;
298       ierr = KSPSetUp(ksp);CHKERRQ(ierr);
299       ierr = PCFactorGetMatrix(pc, &fact);CHKERRQ(ierr);
300       ierr = MatDuplicate(Bd, MAT_DO_NOT_COPY_VALUES, &AinvBd);CHKERRQ(ierr);
301       ierr = MatMatSolve(fact, Bd, AinvBd);CHKERRQ(ierr);
302     } else {
303       PetscBool ex = PETSC_TRUE;
304 
305       if (ex) {
306         Mat Ainvd;
307 
308         ierr = PCComputeExplicitOperator(pc, &Ainvd);CHKERRQ(ierr);
309         ierr = MatMatMult(Ainvd, Bd, MAT_INITIAL_MATRIX, fill, &AinvBd);CHKERRQ(ierr);
310         ierr = MatDestroy(&Ainvd);CHKERRQ(ierr);
311       } else {
312         Vec         sol,rhs;
313         PetscScalar *arrayrhs,*arraysol;
314         PetscInt    i,nrhs,n;
315 
316         ierr = MatDuplicate(Bd, MAT_DO_NOT_COPY_VALUES, &AinvBd);CHKERRQ(ierr);
317         ierr = MatGetSize(Bd,&n,&nrhs);CHKERRQ(ierr);
318         ierr = MatDenseGetArray(Bd,&arrayrhs);CHKERRQ(ierr);
319         ierr = MatDenseGetArray(AinvBd,&arraysol);CHKERRQ(ierr);
320         ierr = KSPGetSolution(ksp,&sol);CHKERRQ(ierr);
321         ierr = KSPGetRhs(ksp,&rhs);CHKERRQ(ierr);
322         for (i=0;i<nrhs;i++) {
323           ierr = VecPlaceArray(rhs,arrayrhs+i*n);CHKERRQ(ierr);
324           ierr = VecPlaceArray(sol,arraysol+i*n);CHKERRQ(ierr);
325           ierr = KSPSolve(ksp,rhs,sol);CHKERRQ(ierr);
326           ierr = VecResetArray(rhs);CHKERRQ(ierr);
327           ierr = VecResetArray(sol);CHKERRQ(ierr);
328         }
329         ierr = MatDenseRestoreArray(Bd,&arrayrhs);CHKERRQ(ierr);
330         ierr = MatDenseRestoreArray(AinvBd,&arrayrhs);CHKERRQ(ierr);
331       }
332     }
333     if (!Bdense & !issym) {
334       ierr = MatDestroy(&Bd);CHKERRQ(ierr);
335     }
336 
337     if (!issym) {
338       if (!Cdense) {
339         ierr = MatConvert(C, MATSEQDENSE, MAT_INITIAL_MATRIX, &Cd);CHKERRQ(ierr);
340       } else {
341         Cd = C;
342       }
343       ierr = MatMatMult(Cd, AinvBd, reuse, fill, S);CHKERRQ(ierr);
344       if (!Cdense) {
345         ierr = MatDestroy(&Cd);CHKERRQ(ierr);
346       }
347     } else {
348       ierr = MatTransposeMatMult(Bd, AinvBd, reuse, fill, S);CHKERRQ(ierr);
349       if (!Bdense) {
350         ierr = MatDestroy(&Bd);CHKERRQ(ierr);
351       }
352     }
353     ierr = MatDestroy(&AinvBd);CHKERRQ(ierr);
354   }
355 
356   if (D) {
357     Mat       Dd;
358     PetscBool Ddense;
359 
360     ierr = PetscObjectTypeCompare((PetscObject)D,MATSEQDENSE,&Ddense);CHKERRQ(ierr);
361     if (!Ddense) {
362       ierr = MatConvert(D, MATSEQDENSE, MAT_INITIAL_MATRIX, &Dd);CHKERRQ(ierr);
363     } else {
364       Dd = D;
365     }
366     if (n_I) {
367       ierr = MatAYPX(*S,-1.0,Dd,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
368     } else {
369       if (reuse == MAT_INITIAL_MATRIX) {
370         ierr = MatDuplicate(Dd,MAT_COPY_VALUES,S);CHKERRQ(ierr);
371       } else {
372         ierr = MatCopy(Dd,*S,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
373       }
374     }
375     if (!Ddense) {
376       ierr = MatDestroy(&Dd);CHKERRQ(ierr);
377     }
378   } else {
379     ierr = MatScale(*S,-1.0);CHKERRQ(ierr);
380   }
381   PetscFunctionReturn(0);
382 }
383 
384 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)
385 {
386   Mat                    F,A_II,A_IB,A_BI,A_BB,AE_II;
387   Mat                    S_all;
388   Mat                    global_schur_subsets,work_mat,*submats;
389   ISLocalToGlobalMapping l2gmap_subsets;
390   IS                     is_I,is_I_layer;
391   IS                     all_subsets,all_subsets_mult,all_subsets_n;
392   PetscInt               *nnz,*all_local_idx_N;
393   PetscInt               *auxnum1,*auxnum2;
394   PetscInt               i,subset_size,max_subset_size;
395   PetscInt               n_B,extra,local_size,global_size;
396   PetscBLASInt           B_N,B_ierr,B_lwork,*pivots;
397   PetscScalar            *Bwork;
398   PetscSubcomm           subcomm;
399   PetscMPIInt            color,rank;
400   MPI_Comm               comm_n;
401   PetscBool              deluxe = PETSC_TRUE, use_getr = PETSC_FALSE;
402   PetscErrorCode         ierr;
403 
404   PetscFunctionBegin;
405   ierr = MatDestroy(&sub_schurs->A);CHKERRQ(ierr);
406   ierr = MatDestroy(&sub_schurs->S);CHKERRQ(ierr);
407 
408   sub_schurs->is_hermitian = PETSC_TRUE;
409   sub_schurs->is_posdef    = PETSC_TRUE;
410   if (benign_trick) sub_schurs->is_posdef = PETSC_FALSE;
411   ierr = PetscOptionsBegin(PetscObjectComm((PetscObject)sub_schurs->l2gmap),sub_schurs->prefix,"BDDC sub_schurs options","PC");CHKERRQ(ierr);
412   ierr = PetscOptionsBool("-sub_schurs_hermitian","Hermitian problem",NULL,sub_schurs->is_hermitian,&sub_schurs->is_hermitian,NULL);CHKERRQ(ierr);
413   ierr = PetscOptionsBool("-sub_schurs_posdef","Positive definite problem",NULL,sub_schurs->is_posdef,&sub_schurs->is_posdef,NULL);CHKERRQ(ierr);
414   ierr = PetscOptionsEnd();CHKERRQ(ierr);
415 
416   /* convert matrix if needed */
417   if (Ain) {
418     PetscBool isseqaij;
419     ierr = PetscObjectTypeCompare((PetscObject)Ain,MATSEQAIJ,&isseqaij);CHKERRQ(ierr);
420     if (isseqaij) {
421       ierr = PetscObjectReference((PetscObject)Ain);CHKERRQ(ierr);
422       sub_schurs->A = Ain;
423     } else {
424       ierr = MatConvert(Ain,MATSEQAIJ,MAT_INITIAL_MATRIX,&sub_schurs->A);CHKERRQ(ierr);
425     }
426   }
427 
428   ierr = PetscObjectReference((PetscObject)Sin);CHKERRQ(ierr);
429   sub_schurs->S = Sin;
430   if (sub_schurs->schur_explicit) {
431     sub_schurs->schur_explicit = (PetscBool)(!!sub_schurs->A);
432   }
433 
434   /* preliminary checks */
435   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");
436 
437   /* restrict work on active processes */
438   color = 0;
439   if (!sub_schurs->n_subs) color = 1; /* this can happen if we are in a multilevel case or if the subdomain is disconnected */
440   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)sub_schurs->l2gmap),&rank);CHKERRQ(ierr);
441   ierr = PetscSubcommCreate(PetscObjectComm((PetscObject)sub_schurs->l2gmap),&subcomm);CHKERRQ(ierr);
442   ierr = PetscSubcommSetNumber(subcomm,2);CHKERRQ(ierr);
443   ierr = PetscSubcommSetTypeGeneral(subcomm,color,rank);CHKERRQ(ierr);
444   ierr = PetscCommDuplicate(PetscSubcommChild(subcomm),&comm_n,NULL);CHKERRQ(ierr);
445   ierr = PetscSubcommDestroy(&subcomm);CHKERRQ(ierr);
446   if (!sub_schurs->n_subs) {
447     ierr = PetscCommDestroy(&comm_n);CHKERRQ(ierr);
448     PetscFunctionReturn(0);
449   }
450   /* ierr = PetscCommDuplicate(PetscObjectComm((PetscObject)sub_schurs->l2gmap),&comm_n,NULL);CHKERRQ(ierr); */
451 
452   /* get Schur complement matrices */
453   if (!sub_schurs->schur_explicit) {
454     Mat       tA_IB,tA_BI,tA_BB;
455     PetscBool isseqsbaij;
456     ierr = MatSchurComplementGetSubMatrices(sub_schurs->S,&A_II,NULL,&tA_IB,&tA_BI,&tA_BB);CHKERRQ(ierr);
457     ierr = PetscObjectTypeCompare((PetscObject)tA_BB,MATSEQSBAIJ,&isseqsbaij);CHKERRQ(ierr);
458     if (isseqsbaij) {
459       ierr = MatConvert(tA_BB,MATSEQAIJ,MAT_INITIAL_MATRIX,&A_BB);CHKERRQ(ierr);
460       ierr = MatConvert(tA_IB,MATSEQAIJ,MAT_INITIAL_MATRIX,&A_IB);CHKERRQ(ierr);
461       ierr = MatConvert(tA_BI,MATSEQAIJ,MAT_INITIAL_MATRIX,&A_BI);CHKERRQ(ierr);
462     } else {
463       ierr = PetscObjectReference((PetscObject)tA_BB);CHKERRQ(ierr);
464       A_BB = tA_BB;
465       ierr = PetscObjectReference((PetscObject)tA_IB);CHKERRQ(ierr);
466       A_IB = tA_IB;
467       ierr = PetscObjectReference((PetscObject)tA_BI);CHKERRQ(ierr);
468       A_BI = tA_BI;
469     }
470   } else {
471     A_II = NULL;
472     A_IB = NULL;
473     A_BI = NULL;
474     A_BB = NULL;
475   }
476   S_all = NULL;
477 
478   /* determine interior problems */
479   ierr = ISGetLocalSize(sub_schurs->is_I,&i);CHKERRQ(ierr);
480   if (nlayers >= 0 && i) { /* Interior problems can be different from the original one */
481     PetscBT                touched;
482     const PetscInt*        idx_B;
483     PetscInt               n_I,n_B,n_local_dofs,n_prev_added,j,layer,*local_numbering;
484 
485     if (!xadj) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Cannot request layering without adjacency");
486     /* get sizes */
487     ierr = ISGetLocalSize(sub_schurs->is_I,&n_I);CHKERRQ(ierr);
488     ierr = ISGetLocalSize(sub_schurs->is_B,&n_B);CHKERRQ(ierr);
489 
490     ierr = PetscMalloc1(n_I+n_B,&local_numbering);CHKERRQ(ierr);
491     ierr = PetscBTCreate(n_I+n_B,&touched);CHKERRQ(ierr);
492     ierr = PetscBTMemzero(n_I+n_B,touched);CHKERRQ(ierr);
493 
494     /* all boundary dofs must be skipped when adding layers */
495     ierr = ISGetIndices(sub_schurs->is_B,&idx_B);CHKERRQ(ierr);
496     for (j=0;j<n_B;j++) {
497       ierr = PetscBTSet(touched,idx_B[j]);CHKERRQ(ierr);
498     }
499     ierr = PetscMemcpy(local_numbering,idx_B,n_B*sizeof(PetscInt));CHKERRQ(ierr);
500     ierr = ISRestoreIndices(sub_schurs->is_B,&idx_B);CHKERRQ(ierr);
501 
502     /* add prescribed number of layers of dofs */
503     n_local_dofs = n_B;
504     n_prev_added = n_B;
505     for (layer=0;layer<nlayers;layer++) {
506       PetscInt n_added;
507       if (n_local_dofs == n_I+n_B) break;
508       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);
509       ierr = PCBDDCAdjGetNextLayer_Private(local_numbering+n_local_dofs,n_prev_added,touched,xadj,adjncy,&n_added);CHKERRQ(ierr);
510       n_prev_added = n_added;
511       n_local_dofs += n_added;
512       if (!n_added) break;
513     }
514     ierr = PetscBTDestroy(&touched);CHKERRQ(ierr);
515 
516     /* IS for I layer dofs in original numbering */
517     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);
518     ierr = PetscFree(local_numbering);CHKERRQ(ierr);
519     ierr = ISSort(is_I_layer);CHKERRQ(ierr);
520     /* IS for I layer dofs in I numbering */
521     if (!sub_schurs->schur_explicit) {
522       ISLocalToGlobalMapping ItoNmap;
523       ierr = ISLocalToGlobalMappingCreateIS(sub_schurs->is_I,&ItoNmap);CHKERRQ(ierr);
524       ierr = ISGlobalToLocalMappingApplyIS(ItoNmap,IS_GTOLM_DROP,is_I_layer,&is_I);CHKERRQ(ierr);
525       ierr = ISLocalToGlobalMappingDestroy(&ItoNmap);CHKERRQ(ierr);
526 
527       /* II block */
528       ierr = MatCreateSubMatrix(A_II,is_I,is_I,MAT_INITIAL_MATRIX,&AE_II);CHKERRQ(ierr);
529     }
530   } else {
531     PetscInt n_I;
532 
533     /* IS for I dofs in original numbering */
534     ierr = PetscObjectReference((PetscObject)sub_schurs->is_I);CHKERRQ(ierr);
535     is_I_layer = sub_schurs->is_I;
536 
537     /* IS for I dofs in I numbering (strided 1) */
538     if (!sub_schurs->schur_explicit) {
539       ierr = ISGetSize(sub_schurs->is_I,&n_I);CHKERRQ(ierr);
540       ierr = ISCreateStride(PetscObjectComm((PetscObject)sub_schurs->is_I),n_I,0,1,&is_I);CHKERRQ(ierr);
541 
542       /* II block is the same */
543       ierr = PetscObjectReference((PetscObject)A_II);CHKERRQ(ierr);
544       AE_II = A_II;
545     }
546   }
547 
548   /* Get info on subset sizes and sum of all subsets sizes */
549   max_subset_size = 0;
550   local_size = 0;
551   for (i=0;i<sub_schurs->n_subs;i++) {
552     ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
553     max_subset_size = PetscMax(subset_size,max_subset_size);
554     local_size += subset_size;
555   }
556 
557   /* Work arrays for local indices */
558   extra = 0;
559   ierr = ISGetLocalSize(sub_schurs->is_B,&n_B);CHKERRQ(ierr);
560   if (sub_schurs->schur_explicit && is_I_layer) {
561     ierr = ISGetLocalSize(is_I_layer,&extra);CHKERRQ(ierr);
562   }
563   ierr = PetscMalloc1(n_B+extra,&all_local_idx_N);CHKERRQ(ierr);
564   if (extra) {
565     const PetscInt *idxs;
566     ierr = ISGetIndices(is_I_layer,&idxs);CHKERRQ(ierr);
567     ierr = PetscMemcpy(all_local_idx_N,idxs,extra*sizeof(PetscInt));CHKERRQ(ierr);
568     ierr = ISRestoreIndices(is_I_layer,&idxs);CHKERRQ(ierr);
569   }
570   ierr = PetscMalloc1(local_size,&nnz);CHKERRQ(ierr);
571   ierr = PetscMalloc1(sub_schurs->n_subs,&auxnum1);CHKERRQ(ierr);
572   ierr = PetscMalloc1(sub_schurs->n_subs,&auxnum2);CHKERRQ(ierr);
573 
574   /* Get local indices in local numbering */
575   local_size = 0;
576   for (i=0;i<sub_schurs->n_subs;i++) {
577     PetscInt j;
578     const    PetscInt *idxs;
579 
580     ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
581     ierr = ISGetIndices(sub_schurs->is_subs[i],&idxs);CHKERRQ(ierr);
582     /* start (smallest in global ordering) and multiplicity */
583     auxnum1[i] = idxs[0];
584     auxnum2[i] = subset_size;
585     /* subset indices in local numbering */
586     ierr = PetscMemcpy(all_local_idx_N+local_size+extra,idxs,subset_size*sizeof(PetscInt));CHKERRQ(ierr);
587     ierr = ISRestoreIndices(sub_schurs->is_subs[i],&idxs);CHKERRQ(ierr);
588     for (j=0;j<subset_size;j++) nnz[local_size+j] = subset_size;
589     local_size += subset_size;
590   }
591 
592   /* allocate extra workspace needed only for GETRI */
593   if (local_size && !benign_trick && (!sub_schurs->is_hermitian || !sub_schurs->is_posdef)) {
594     PetscScalar  lwork,dummyscalar = 0.;
595     PetscBLASInt dummyint = 0;
596 
597     use_getr = PETSC_TRUE;
598     B_lwork = -1;
599     ierr = PetscBLASIntCast(local_size,&B_N);CHKERRQ(ierr);
600     ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
601     PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,&dummyscalar,&B_N,&dummyint,&lwork,&B_lwork,&B_ierr));
602     ierr = PetscFPTrapPop();CHKERRQ(ierr);
603     if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in query to GETRI Lapack routine %d",(int)B_ierr);
604     ierr = PetscBLASIntCast((PetscInt)PetscRealPart(lwork),&B_lwork);CHKERRQ(ierr);
605     ierr = PetscMalloc2(B_lwork,&Bwork,B_N,&pivots);CHKERRQ(ierr);
606   } else {
607     Bwork = NULL;
608     pivots = NULL;
609   }
610 
611   /* prepare parallel matrices for summing up properly schurs on subsets */
612   ierr = ISCreateGeneral(comm_n,sub_schurs->n_subs,auxnum1,PETSC_OWN_POINTER,&all_subsets_n);CHKERRQ(ierr);
613   ierr = ISLocalToGlobalMappingApplyIS(sub_schurs->l2gmap,all_subsets_n,&all_subsets);CHKERRQ(ierr);
614   ierr = ISDestroy(&all_subsets_n);CHKERRQ(ierr);
615   ierr = ISCreateGeneral(comm_n,sub_schurs->n_subs,auxnum2,PETSC_OWN_POINTER,&all_subsets_mult);CHKERRQ(ierr);
616   ierr = ISRenumber(all_subsets,all_subsets_mult,&global_size,&all_subsets_n);CHKERRQ(ierr);
617   ierr = ISDestroy(&all_subsets);CHKERRQ(ierr);
618   ierr = ISDestroy(&all_subsets_mult);CHKERRQ(ierr);
619   ierr = ISGetLocalSize(all_subsets_n,&i);CHKERRQ(ierr);
620   if (i != local_size) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Invalid size of new subset! %D != %D",i,local_size);
621   ierr = ISLocalToGlobalMappingCreateIS(all_subsets_n,&l2gmap_subsets);CHKERRQ(ierr);
622   ierr = MatCreateIS(comm_n,1,PETSC_DECIDE,PETSC_DECIDE,global_size,global_size,l2gmap_subsets,NULL,&work_mat);CHKERRQ(ierr);
623   ierr = ISLocalToGlobalMappingDestroy(&l2gmap_subsets);CHKERRQ(ierr);
624   ierr = MatCreate(PetscObjectComm((PetscObject)work_mat),&global_schur_subsets);CHKERRQ(ierr);
625   ierr = MatSetSizes(global_schur_subsets,PETSC_DECIDE,PETSC_DECIDE,global_size,global_size);CHKERRQ(ierr);
626   ierr = MatSetType(global_schur_subsets,MATMPIAIJ);CHKERRQ(ierr);
627 
628   /* subset indices in local boundary numbering */
629   if (!sub_schurs->is_Ej_all) {
630     PetscInt *all_local_idx_B;
631 
632     ierr = PetscMalloc1(local_size,&all_local_idx_B);CHKERRQ(ierr);
633     ierr = ISGlobalToLocalMappingApply(sub_schurs->BtoNmap,IS_GTOLM_DROP,local_size,all_local_idx_N+extra,&subset_size,all_local_idx_B);CHKERRQ(ierr);
634     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);
635     ierr = ISCreateGeneral(PETSC_COMM_SELF,local_size,all_local_idx_B,PETSC_OWN_POINTER,&sub_schurs->is_Ej_all);CHKERRQ(ierr);
636   }
637 
638   if (change) {
639     ISLocalToGlobalMapping BtoS;
640     IS                     change_primal_B;
641     IS                     change_primal_all;
642 
643     if (sub_schurs->change_primal_sub) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"This should not happen");
644     if (sub_schurs->change) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"This should not happen");
645     ierr = PetscMalloc1(sub_schurs->n_subs,&sub_schurs->change_primal_sub);CHKERRQ(ierr);
646     for (i=0;i<sub_schurs->n_subs;i++) {
647       ISLocalToGlobalMapping NtoS;
648       ierr = ISLocalToGlobalMappingCreateIS(sub_schurs->is_subs[i],&NtoS);CHKERRQ(ierr);
649       ierr = ISGlobalToLocalMappingApplyIS(NtoS,IS_GTOLM_DROP,change_primal,&sub_schurs->change_primal_sub[i]);CHKERRQ(ierr);
650       ierr = ISLocalToGlobalMappingDestroy(&NtoS);CHKERRQ(ierr);
651     }
652     ierr = ISGlobalToLocalMappingApplyIS(sub_schurs->BtoNmap,IS_GTOLM_DROP,change_primal,&change_primal_B);CHKERRQ(ierr);
653     ierr = ISLocalToGlobalMappingCreateIS(sub_schurs->is_Ej_all,&BtoS);CHKERRQ(ierr);
654     ierr = ISGlobalToLocalMappingApplyIS(BtoS,IS_GTOLM_DROP,change_primal_B,&change_primal_all);CHKERRQ(ierr);
655     ierr = ISLocalToGlobalMappingDestroy(&BtoS);CHKERRQ(ierr);
656     ierr = ISDestroy(&change_primal_B);CHKERRQ(ierr);
657     ierr = PetscMalloc1(sub_schurs->n_subs,&sub_schurs->change);CHKERRQ(ierr);
658     for (i=0;i<sub_schurs->n_subs;i++) {
659       Mat change_sub;
660 
661       ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
662       ierr = KSPCreate(PETSC_COMM_SELF,&sub_schurs->change[i]);CHKERRQ(ierr);
663       ierr = KSPSetType(sub_schurs->change[i],KSPPREONLY);CHKERRQ(ierr);
664       if (!sub_schurs->change_with_qr) {
665         ierr = MatCreateSubMatrix(change,sub_schurs->is_subs[i],sub_schurs->is_subs[i],MAT_INITIAL_MATRIX,&change_sub);CHKERRQ(ierr);
666       } else {
667         Mat change_subt;
668         ierr = MatCreateSubMatrix(change,sub_schurs->is_subs[i],sub_schurs->is_subs[i],MAT_INITIAL_MATRIX,&change_subt);CHKERRQ(ierr);
669         ierr = MatConvert(change_subt,MATSEQDENSE,MAT_INITIAL_MATRIX,&change_sub);CHKERRQ(ierr);
670         ierr = MatDestroy(&change_subt);CHKERRQ(ierr);
671       }
672       ierr = KSPSetOperators(sub_schurs->change[i],change_sub,change_sub);CHKERRQ(ierr);
673       ierr = MatDestroy(&change_sub);CHKERRQ(ierr);
674       ierr = KSPSetOptionsPrefix(sub_schurs->change[i],sub_schurs->prefix);CHKERRQ(ierr);
675       ierr = KSPAppendOptionsPrefix(sub_schurs->change[i],"sub_schurs_change_");CHKERRQ(ierr);
676     }
677     ierr = ISDestroy(&change_primal_all);CHKERRQ(ierr);
678   }
679 
680   /* Local matrix of all local Schur on subsets (transposed) */
681   if (!sub_schurs->S_Ej_all) {
682     ierr = MatCreate(PETSC_COMM_SELF,&sub_schurs->S_Ej_all);CHKERRQ(ierr);
683     ierr = MatSetSizes(sub_schurs->S_Ej_all,PETSC_DECIDE,PETSC_DECIDE,local_size,local_size);CHKERRQ(ierr);
684     ierr = MatSetType(sub_schurs->S_Ej_all,MATAIJ);CHKERRQ(ierr);
685     ierr = MatSeqAIJSetPreallocation(sub_schurs->S_Ej_all,0,nnz);CHKERRQ(ierr);
686   }
687 
688   /* Compute Schur complements explicitly */
689   F = NULL;
690   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 */
691     Mat         S_Ej_expl;
692     PetscScalar *work;
693     PetscInt    j,*dummy_idx;
694     PetscBool   Sdense;
695 
696     ierr = PetscMalloc2(max_subset_size,&dummy_idx,max_subset_size*max_subset_size,&work);CHKERRQ(ierr);
697     local_size = 0;
698     for (i=0;i<sub_schurs->n_subs;i++) {
699       IS  is_subset_B;
700       Mat AE_EE,AE_IE,AE_EI,S_Ej;
701 
702       /* subsets in original and boundary numbering */
703       ierr = ISGlobalToLocalMappingApplyIS(sub_schurs->BtoNmap,IS_GTOLM_DROP,sub_schurs->is_subs[i],&is_subset_B);CHKERRQ(ierr);
704       /* EE block */
705       ierr = MatCreateSubMatrix(A_BB,is_subset_B,is_subset_B,MAT_INITIAL_MATRIX,&AE_EE);CHKERRQ(ierr);
706       /* IE block */
707       ierr = MatCreateSubMatrix(A_IB,is_I,is_subset_B,MAT_INITIAL_MATRIX,&AE_IE);CHKERRQ(ierr);
708       /* EI block */
709       if (sub_schurs->is_hermitian) {
710         ierr = MatCreateTranspose(AE_IE,&AE_EI);CHKERRQ(ierr);
711       } else {
712         ierr = MatCreateSubMatrix(A_BI,is_subset_B,is_I,MAT_INITIAL_MATRIX,&AE_EI);CHKERRQ(ierr);
713       }
714       ierr = ISDestroy(&is_subset_B);CHKERRQ(ierr);
715       ierr = MatCreateSchurComplement(AE_II,AE_II,AE_IE,AE_EI,AE_EE,&S_Ej);CHKERRQ(ierr);
716       ierr = MatDestroy(&AE_EE);CHKERRQ(ierr);
717       ierr = MatDestroy(&AE_IE);CHKERRQ(ierr);
718       ierr = MatDestroy(&AE_EI);CHKERRQ(ierr);
719       if (AE_II == A_II) { /* we can reuse the same ksp */
720         KSP ksp;
721         ierr = MatSchurComplementGetKSP(sub_schurs->S,&ksp);CHKERRQ(ierr);
722         ierr = MatSchurComplementSetKSP(S_Ej,ksp);CHKERRQ(ierr);
723       } else { /* build new ksp object which inherits ksp and pc types from the original one */
724         KSP       origksp,schurksp;
725         PC        origpc,schurpc;
726         KSPType   ksp_type;
727         PetscInt  n_internal;
728         PetscBool ispcnone;
729 
730         ierr = MatSchurComplementGetKSP(sub_schurs->S,&origksp);CHKERRQ(ierr);
731         ierr = MatSchurComplementGetKSP(S_Ej,&schurksp);CHKERRQ(ierr);
732         ierr = KSPGetType(origksp,&ksp_type);CHKERRQ(ierr);
733         ierr = KSPSetType(schurksp,ksp_type);CHKERRQ(ierr);
734         ierr = KSPGetPC(schurksp,&schurpc);CHKERRQ(ierr);
735         ierr = KSPGetPC(origksp,&origpc);CHKERRQ(ierr);
736         ierr = PetscObjectTypeCompare((PetscObject)origpc,PCNONE,&ispcnone);CHKERRQ(ierr);
737         if (!ispcnone) {
738           PCType pc_type;
739           ierr = PCGetType(origpc,&pc_type);CHKERRQ(ierr);
740           ierr = PCSetType(schurpc,pc_type);CHKERRQ(ierr);
741         } else {
742           ierr = PCSetType(schurpc,PCLU);CHKERRQ(ierr);
743         }
744         ierr = ISGetSize(is_I,&n_internal);CHKERRQ(ierr);
745         if (n_internal) { /* UMFPACK gives error with 0 sized problems */
746           MatSolverPackage solver=NULL;
747           ierr = PCFactorGetMatSolverPackage(origpc,(const MatSolverPackage*)&solver);CHKERRQ(ierr);
748           if (solver) {
749             ierr = PCFactorSetMatSolverPackage(schurpc,solver);CHKERRQ(ierr);
750           }
751         }
752         ierr = KSPSetUp(schurksp);CHKERRQ(ierr);
753       }
754       ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
755       ierr = MatCreateSeqDense(PETSC_COMM_SELF,subset_size,subset_size,work,&S_Ej_expl);CHKERRQ(ierr);
756       ierr = PCBDDCComputeExplicitSchur(S_Ej,sub_schurs->is_hermitian,MAT_REUSE_MATRIX,&S_Ej_expl);CHKERRQ(ierr);
757       ierr = PetscObjectTypeCompare((PetscObject)S_Ej_expl,MATSEQDENSE,&Sdense);CHKERRQ(ierr);
758       if (Sdense) {
759         for (j=0;j<subset_size;j++) {
760           dummy_idx[j]=local_size+j;
761         }
762         ierr = MatSetValues(sub_schurs->S_Ej_all,subset_size,dummy_idx,subset_size,dummy_idx,work,INSERT_VALUES);CHKERRQ(ierr);
763       } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Not yet implemented for sparse matrices");
764       ierr = MatDestroy(&S_Ej);CHKERRQ(ierr);
765       ierr = MatDestroy(&S_Ej_expl);CHKERRQ(ierr);
766       local_size += subset_size;
767     }
768     ierr = PetscFree2(dummy_idx,work);CHKERRQ(ierr);
769     /* free */
770     ierr = ISDestroy(&is_I);CHKERRQ(ierr);
771     ierr = MatDestroy(&AE_II);CHKERRQ(ierr);
772     ierr = PetscFree(all_local_idx_N);CHKERRQ(ierr);
773   } else {
774     Mat         A,cs_AIB_mat = NULL,benign_AIIm1_ones_mat = NULL;
775     Vec         Dall = NULL;
776     IS          is_A_all,*is_p_r = NULL;
777     PetscScalar *work,*S_data,*schur_factor,infty = PETSC_MAX_REAL;
778     PetscInt    n,n_I,*dummy_idx,size_schur,size_active_schur,cum,cum2;
779     PetscBool   economic,solver_S,S_lower_triangular = PETSC_FALSE;
780     PetscBool   schur_has_vertices,factor_workaround;
781     char        solver[256];
782 
783     /* get sizes */
784     n_I = 0;
785     if (is_I_layer) {
786       ierr = ISGetLocalSize(is_I_layer,&n_I);CHKERRQ(ierr);
787     }
788     economic = PETSC_FALSE;
789     ierr = ISGetLocalSize(sub_schurs->is_I,&cum);CHKERRQ(ierr);
790     if (cum != n_I) economic = PETSC_TRUE;
791     ierr = MatGetLocalSize(sub_schurs->A,&n,NULL);CHKERRQ(ierr);
792     size_active_schur = local_size;
793 
794     /* import scaling vector (wrong formulation if we have 3D edges) */
795     if (scaling && compute_Stilda) {
796       const PetscScalar *array;
797       PetscScalar       *array2;
798       const PetscInt    *idxs;
799       PetscInt          i;
800 
801       ierr = ISGetIndices(sub_schurs->is_Ej_all,&idxs);CHKERRQ(ierr);
802       ierr = VecCreateSeq(PETSC_COMM_SELF,size_active_schur,&Dall);CHKERRQ(ierr);
803       ierr = VecGetArrayRead(scaling,&array);CHKERRQ(ierr);
804       ierr = VecGetArray(Dall,&array2);CHKERRQ(ierr);
805       for (i=0;i<size_active_schur;i++) array2[i] = array[idxs[i]];
806       ierr = VecRestoreArray(Dall,&array2);CHKERRQ(ierr);
807       ierr = VecRestoreArrayRead(scaling,&array);CHKERRQ(ierr);
808       ierr = ISRestoreIndices(sub_schurs->is_Ej_all,&idxs);CHKERRQ(ierr);
809       deluxe = PETSC_FALSE;
810     }
811 
812     /* size active schurs does not count any dirichlet or vertex dof on the interface */
813     factor_workaround = PETSC_FALSE;
814     schur_has_vertices = PETSC_FALSE;
815     cum = n_I+size_active_schur;
816     if (sub_schurs->is_dir) {
817       const PetscInt* idxs;
818       PetscInt        n_dir;
819 
820       ierr = ISGetLocalSize(sub_schurs->is_dir,&n_dir);CHKERRQ(ierr);
821       ierr = ISGetIndices(sub_schurs->is_dir,&idxs);CHKERRQ(ierr);
822       ierr = PetscMemcpy(all_local_idx_N+cum,idxs,n_dir*sizeof(PetscInt));CHKERRQ(ierr);
823       ierr = ISRestoreIndices(sub_schurs->is_dir,&idxs);CHKERRQ(ierr);
824       cum += n_dir;
825       factor_workaround = PETSC_TRUE;
826     }
827     /* include the primal vertices in the Schur complement */
828     if (exact_schur && sub_schurs->is_vertices && (compute_Stilda || benign_n)) {
829       PetscInt n_v;
830 
831       ierr = ISGetLocalSize(sub_schurs->is_vertices,&n_v);CHKERRQ(ierr);
832       if (n_v) {
833         const PetscInt* idxs;
834 
835         ierr = ISGetIndices(sub_schurs->is_vertices,&idxs);CHKERRQ(ierr);
836         ierr = PetscMemcpy(all_local_idx_N+cum,idxs,n_v*sizeof(PetscInt));CHKERRQ(ierr);
837         ierr = ISRestoreIndices(sub_schurs->is_vertices,&idxs);CHKERRQ(ierr);
838         cum += n_v;
839         factor_workaround = PETSC_TRUE;
840         schur_has_vertices = PETSC_TRUE;
841       }
842     }
843     size_schur = cum - n_I;
844     ierr = ISCreateGeneral(PETSC_COMM_SELF,cum,all_local_idx_N,PETSC_OWN_POINTER,&is_A_all);CHKERRQ(ierr);
845     /* get working mat (TODO: factorize without actually permuting)  */
846     if (cum == n) {
847       ierr = ISSetPermutation(is_A_all);CHKERRQ(ierr);
848       ierr = MatPermute(sub_schurs->A,is_A_all,is_A_all,&A);CHKERRQ(ierr);
849     } else {
850       ierr = MatCreateSubMatrix(sub_schurs->A,is_A_all,is_A_all,MAT_INITIAL_MATRIX,&A);CHKERRQ(ierr);
851     }
852     ierr = MatSetOptionsPrefix(A,sub_schurs->prefix);CHKERRQ(ierr);
853     ierr = MatAppendOptionsPrefix(A,"sub_schurs_");CHKERRQ(ierr);
854 
855     /* if we actually change the basis for the pressures, LDL^T factors will use a lot of memory
856        n^2 instead of n^1.5 or something. This is a workaround */
857     if (benign_n) {
858       Vec                    v;
859       ISLocalToGlobalMapping N_to_reor;
860       IS                     is_p0,is_p0_p;
861       PetscScalar            *cs_AIB,*AIIm1_data;
862       PetscInt               sizeA;
863 
864       ierr = ISLocalToGlobalMappingCreateIS(is_A_all,&N_to_reor);CHKERRQ(ierr);
865       ierr = ISCreateGeneral(PETSC_COMM_SELF,benign_n,benign_p0_lidx,PETSC_COPY_VALUES,&is_p0);CHKERRQ(ierr);
866       ierr = ISGlobalToLocalMappingApplyIS(N_to_reor,IS_GTOLM_DROP,is_p0,&is_p0_p);CHKERRQ(ierr);
867       ierr = ISDestroy(&is_p0);CHKERRQ(ierr);
868       ierr = MatCreateVecs(A,&v,NULL);CHKERRQ(ierr);
869       ierr = VecGetSize(v,&sizeA);CHKERRQ(ierr);
870       ierr = MatCreateSeqDense(PETSC_COMM_SELF,sizeA,benign_n,NULL,&benign_AIIm1_ones_mat);CHKERRQ(ierr);
871       ierr = MatCreateSeqDense(PETSC_COMM_SELF,size_schur,benign_n,NULL,&cs_AIB_mat);CHKERRQ(ierr);
872       ierr = MatDenseGetArray(cs_AIB_mat,&cs_AIB);CHKERRQ(ierr);
873       ierr = MatDenseGetArray(benign_AIIm1_ones_mat,&AIIm1_data);CHKERRQ(ierr);
874       ierr = PetscMalloc1(benign_n,&is_p_r);CHKERRQ(ierr);
875       /* compute colsum of A_IB restricted to pressures */
876       for (i=0;i<benign_n;i++) {
877         Vec            benign_AIIm1_ones;
878         PetscScalar    *array;
879         const PetscInt *idxs;
880         PetscInt       j,nz;
881 
882         ierr = ISGlobalToLocalMappingApplyIS(N_to_reor,IS_GTOLM_DROP,benign_zerodiag_subs[i],&is_p_r[i]);CHKERRQ(ierr);
883         ierr = ISGetLocalSize(is_p_r[i],&nz);CHKERRQ(ierr);
884         ierr = ISGetIndices(is_p_r[i],&idxs);CHKERRQ(ierr);
885         for (j=0;j<nz;j++) AIIm1_data[idxs[j]+sizeA*i] = 1.;
886         ierr = ISRestoreIndices(is_p_r[i],&idxs);CHKERRQ(ierr);
887         ierr = VecCreateSeqWithArray(PETSC_COMM_SELF,1,sizeA,AIIm1_data+sizeA*i,&benign_AIIm1_ones);CHKERRQ(ierr);
888         ierr = MatMult(A,benign_AIIm1_ones,v);CHKERRQ(ierr);
889         ierr = VecDestroy(&benign_AIIm1_ones);CHKERRQ(ierr);
890         ierr = VecGetArray(v,&array);CHKERRQ(ierr);
891         for (j=0;j<size_schur;j++) {
892 #if defined(PETSC_USE_COMPLEX)
893           cs_AIB[i*size_schur + j] = (PetscRealPart(array[j+n_I])/nz + PETSC_i*(PetscImaginaryPart(array[j+n_I])/nz));
894 #else
895           cs_AIB[i*size_schur + j] = array[j+n_I]/nz;
896 #endif
897         }
898         ierr = VecRestoreArray(v,&array);CHKERRQ(ierr);
899       }
900       ierr = MatDenseRestoreArray(cs_AIB_mat,&cs_AIB);CHKERRQ(ierr);
901       ierr = MatDenseRestoreArray(benign_AIIm1_ones_mat,&AIIm1_data);CHKERRQ(ierr);
902       ierr = VecDestroy(&v);CHKERRQ(ierr);
903       ierr = MatSetOption(A,MAT_KEEP_NONZERO_PATTERN,PETSC_FALSE);CHKERRQ(ierr);
904       ierr = MatSetOption(A,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_FALSE);CHKERRQ(ierr);
905       ierr = MatSetOption(A,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);CHKERRQ(ierr);
906       ierr = MatZeroRowsColumnsIS(A,is_p0_p,1.0,NULL,NULL);CHKERRQ(ierr);
907       ierr = ISDestroy(&is_p0_p);CHKERRQ(ierr);
908       ierr = ISLocalToGlobalMappingDestroy(&N_to_reor);CHKERRQ(ierr);
909     }
910     ierr = MatSetOption(A,MAT_SYMMETRIC,sub_schurs->is_hermitian);CHKERRQ(ierr);
911     ierr = MatSetOption(A,MAT_HERMITIAN,sub_schurs->is_hermitian);CHKERRQ(ierr);
912     ierr = MatSetOption(A,MAT_SPD,sub_schurs->is_posdef);CHKERRQ(ierr);
913 #if defined(PETSC_HAVE_MUMPS)
914     ierr = PetscStrcpy(solver,MATSOLVERMUMPS);CHKERRQ(ierr);
915 #else
916     ierr = PetscStrcpy(solver,MATSOLVERMKL_PARDISO);CHKERRQ(ierr);
917 #endif
918     ierr = PetscOptionsGetString(NULL,((PetscObject)A)->prefix,"-mat_solver_package",solver,256,NULL);CHKERRQ(ierr);
919 
920     /* when using the benign subspace trick, the local Schur complements are SPD */
921     if (benign_trick) sub_schurs->is_posdef = PETSC_TRUE;
922 
923     if (n_I) { /* TODO add ordering from options */
924       IS is_schur;
925 
926       if (sub_schurs->is_hermitian && sub_schurs->is_posdef) {
927         ierr = MatGetFactor(A,solver,MAT_FACTOR_CHOLESKY,&F);CHKERRQ(ierr);
928       } else {
929         ierr = MatGetFactor(A,solver,MAT_FACTOR_LU,&F);CHKERRQ(ierr);
930       }
931       ierr = MatSetErrorIfFailure(A,PETSC_TRUE);CHKERRQ(ierr);
932 
933       /* subsets ordered last */
934       ierr = ISCreateStride(PETSC_COMM_SELF,size_schur,n_I,1,&is_schur);CHKERRQ(ierr);
935       ierr = MatFactorSetSchurIS(F,is_schur);CHKERRQ(ierr);
936       ierr = ISDestroy(&is_schur);CHKERRQ(ierr);
937 
938       /* factorization step */
939       if (sub_schurs->is_hermitian && sub_schurs->is_posdef) {
940         ierr = MatCholeskyFactorSymbolic(F,A,NULL,NULL);CHKERRQ(ierr);
941 #if defined(PETSC_HAVE_MUMPS) /* be sure that icntl 19 is not set by command line */
942         ierr = MatMumpsSetIcntl(F,19,2);CHKERRQ(ierr);
943 #endif
944         ierr = MatCholeskyFactorNumeric(F,A,NULL);CHKERRQ(ierr);
945         S_lower_triangular = PETSC_TRUE;
946       } else {
947         ierr = MatLUFactorSymbolic(F,A,NULL,NULL,NULL);CHKERRQ(ierr);
948 #if defined(PETSC_HAVE_MUMPS) /* be sure that icntl 19 is not set by command line */
949         ierr = MatMumpsSetIcntl(F,19,3);CHKERRQ(ierr);
950 #endif
951         ierr = MatLUFactorNumeric(F,A,NULL);CHKERRQ(ierr);
952       }
953       ierr = MatViewFromOptions(F,(PetscObject)A,"-mat_factor_view");CHKERRQ(ierr);
954 
955       /* get explicit Schur Complement computed during numeric factorization */
956       ierr = MatFactorGetSchurComplement(F,&S_all,NULL);CHKERRQ(ierr);
957       ierr = MatSetOption(S_all,MAT_SPD,sub_schurs->is_posdef);CHKERRQ(ierr);
958       ierr = MatSetOption(S_all,MAT_HERMITIAN,sub_schurs->is_hermitian);CHKERRQ(ierr);
959 
960       /* we can reuse the solvers if we are not using the economic version */
961       reuse_solvers = (PetscBool)(reuse_solvers && !economic);
962       factor_workaround = (PetscBool)(reuse_solvers && factor_workaround);
963       solver_S = PETSC_TRUE;
964 
965       /* update the Schur complement with the change of basis on the pressures */
966       if (benign_n) {
967         PetscScalar *S_data,*cs_AIB,*AIIm1_data;
968         Vec         v;
969         PetscInt    sizeA;
970 
971         ierr = MatDenseGetArray(S_all,&S_data);CHKERRQ(ierr);
972         ierr = MatCreateVecs(A,&v,NULL);CHKERRQ(ierr);
973         ierr = VecGetSize(v,&sizeA);CHKERRQ(ierr);
974 #if defined(PETSC_HAVE_MUMPS)
975         ierr = MatMumpsSetIcntl(F,26,0);CHKERRQ(ierr);
976 #endif
977 #if defined(PETSC_HAVE_MKL_PARDISO)
978         ierr = MatMkl_PardisoSetCntl(F,70,1);CHKERRQ(ierr);
979 #endif
980         ierr = MatDenseGetArray(cs_AIB_mat,&cs_AIB);CHKERRQ(ierr);
981         ierr = MatDenseGetArray(benign_AIIm1_ones_mat,&AIIm1_data);CHKERRQ(ierr);
982         for (i=0;i<benign_n;i++) {
983           Vec            benign_AIIm1_ones;
984           PetscScalar    *array,sum = 0.,one = 1.;
985           const PetscInt *idxs;
986           PetscInt       j,nz;
987           PetscBLASInt   B_k,B_n;
988 
989           ierr = VecCreateSeqWithArray(PETSC_COMM_SELF,1,sizeA,AIIm1_data+sizeA*i,&benign_AIIm1_ones);CHKERRQ(ierr);
990           ierr = VecCopy(benign_AIIm1_ones,v);CHKERRQ(ierr);
991           ierr = MatSolve(F,v,benign_AIIm1_ones);CHKERRQ(ierr);
992           ierr = ISGetLocalSize(is_p_r[i],&nz);CHKERRQ(ierr);
993           ierr = ISGetIndices(is_p_r[i],&idxs);CHKERRQ(ierr);
994           /* p0 dof (eliminated) is excluded from the sum */
995           for (j=0;j<nz-1;j++) sum -= AIIm1_data[idxs[j]+sizeA*i];
996           ierr = ISRestoreIndices(is_p_r[i],&idxs);CHKERRQ(ierr);
997           ierr = MatMult(A,benign_AIIm1_ones,v);CHKERRQ(ierr);
998           ierr = VecGetArray(v,&array);CHKERRQ(ierr);
999           /* perform sparse rank updates on symmetric Schur (TODO: move outside of the loop?) */
1000           /* cs_AIB already scaled by 1./nz */
1001           B_k = 1;
1002           ierr = PetscBLASIntCast(size_schur,&B_n);CHKERRQ(ierr);
1003           PetscStackCallBLAS("BLASsyrk",BLASsyrk_("L","N",&B_n,&B_k,&sum,cs_AIB+i*size_schur,&B_n,&one,S_data,&B_n));
1004           sum  = 1.;
1005           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));
1006           ierr = VecRestoreArray(v,&array);CHKERRQ(ierr);
1007           /* set p0 entry of AIIm1_ones to zero */
1008           ierr = ISGetIndices(is_p_r[i],&idxs);CHKERRQ(ierr);
1009           for (j=0;j<benign_n;j++) AIIm1_data[idxs[nz-1]+sizeA*j] = 0.;
1010           ierr = ISRestoreIndices(is_p_r[i],&idxs);CHKERRQ(ierr);
1011           ierr = VecDestroy(&benign_AIIm1_ones);CHKERRQ(ierr);
1012         }
1013   /* restore defaults */
1014 #if defined(PETSC_HAVE_MUMPS)
1015         ierr = MatMumpsSetIcntl(F,26,-1);CHKERRQ(ierr);
1016 #endif
1017 #if defined(PETSC_HAVE_MKL_PARDISO)
1018         ierr = MatMkl_PardisoSetCntl(F,70,0);CHKERRQ(ierr);
1019 #endif
1020         ierr = MatDenseRestoreArray(cs_AIB_mat,&cs_AIB);CHKERRQ(ierr);
1021         ierr = MatDenseRestoreArray(benign_AIIm1_ones_mat,&AIIm1_data);CHKERRQ(ierr);
1022         ierr = VecDestroy(&v);CHKERRQ(ierr);
1023         ierr = MatDenseRestoreArray(S_all,&S_data);CHKERRQ(ierr);
1024       }
1025       if (!reuse_solvers) {
1026         for (i=0;i<benign_n;i++) {
1027           ierr = ISDestroy(&is_p_r[i]);CHKERRQ(ierr);
1028         }
1029         ierr = PetscFree(is_p_r);CHKERRQ(ierr);
1030         ierr = MatDestroy(&cs_AIB_mat);CHKERRQ(ierr);
1031         ierr = MatDestroy(&benign_AIIm1_ones_mat);CHKERRQ(ierr);
1032       }
1033     } else { /* we can't use MatFactor when size_schur == size_of_the_problem */
1034       ierr = MatConvert(A,MATSEQDENSE,MAT_INITIAL_MATRIX,&S_all);CHKERRQ(ierr);
1035       reuse_solvers = PETSC_FALSE; /* TODO: why we can't reuse the solvers here? */
1036       factor_workaround = PETSC_FALSE;
1037       solver_S = PETSC_FALSE;
1038     }
1039 
1040     if (reuse_solvers) {
1041       Mat                A_II,Afake;
1042       Vec                vec1_B;
1043       PCBDDCReuseSolvers msolv_ctx;
1044       PetscInt           n_R;
1045 
1046       if (sub_schurs->reuse_solver) {
1047         ierr = PCBDDCReuseSolversReset(sub_schurs->reuse_solver);CHKERRQ(ierr);
1048       } else {
1049         ierr = PetscNew(&sub_schurs->reuse_solver);CHKERRQ(ierr);
1050       }
1051       msolv_ctx = sub_schurs->reuse_solver;
1052       ierr = MatSchurComplementGetSubMatrices(sub_schurs->S,&A_II,NULL,NULL,NULL,NULL);CHKERRQ(ierr);
1053       ierr = PetscObjectReference((PetscObject)F);CHKERRQ(ierr);
1054       msolv_ctx->F = F;
1055       ierr = MatCreateVecs(F,&msolv_ctx->sol,NULL);CHKERRQ(ierr);
1056       /* currently PETSc has no support for MatSolve(F,x,x), so cheat and let rhs and sol share the same memory */
1057       {
1058         PetscScalar *array;
1059         PetscInt    n;
1060 
1061         ierr = VecGetLocalSize(msolv_ctx->sol,&n);CHKERRQ(ierr);
1062         ierr = VecGetArray(msolv_ctx->sol,&array);CHKERRQ(ierr);
1063         ierr = VecCreateSeqWithArray(PetscObjectComm((PetscObject)msolv_ctx->sol),1,n,array,&msolv_ctx->rhs);CHKERRQ(ierr);
1064         ierr = VecRestoreArray(msolv_ctx->sol,&array);CHKERRQ(ierr);
1065       }
1066       msolv_ctx->has_vertices = schur_has_vertices;
1067 
1068       /* interior solver */
1069       ierr = PCCreate(PetscObjectComm((PetscObject)A_II),&msolv_ctx->interior_solver);CHKERRQ(ierr);
1070       ierr = PCSetOperators(msolv_ctx->interior_solver,A_II,A_II);CHKERRQ(ierr);
1071       ierr = PCSetType(msolv_ctx->interior_solver,PCSHELL);CHKERRQ(ierr);
1072       ierr = PCShellSetContext(msolv_ctx->interior_solver,msolv_ctx);CHKERRQ(ierr);
1073       ierr = PCShellSetApply(msolv_ctx->interior_solver,PCBDDCReuseSolvers_Interior);CHKERRQ(ierr);
1074       ierr = PCShellSetApplyTranspose(msolv_ctx->interior_solver,PCBDDCReuseSolvers_InteriorTranspose);CHKERRQ(ierr);
1075 
1076       /* correction solver */
1077       ierr = PCCreate(PetscObjectComm((PetscObject)A_II),&msolv_ctx->correction_solver);CHKERRQ(ierr);
1078       ierr = PCSetType(msolv_ctx->correction_solver,PCSHELL);CHKERRQ(ierr);
1079       ierr = PCShellSetContext(msolv_ctx->correction_solver,msolv_ctx);CHKERRQ(ierr);
1080       ierr = PCShellSetApply(msolv_ctx->correction_solver,PCBDDCReuseSolvers_Correction);CHKERRQ(ierr);
1081       ierr = PCShellSetApplyTranspose(msolv_ctx->correction_solver,PCBDDCReuseSolvers_CorrectionTranspose);CHKERRQ(ierr);
1082 
1083       /* scatter and vecs for Schur complement solver */
1084       ierr = MatCreateVecs(S_all,&msolv_ctx->sol_B,&msolv_ctx->rhs_B);CHKERRQ(ierr);
1085       ierr = MatCreateVecs(sub_schurs->S,&vec1_B,NULL);CHKERRQ(ierr);
1086       if (!schur_has_vertices) {
1087         ierr = ISGlobalToLocalMappingApplyIS(sub_schurs->BtoNmap,IS_GTOLM_DROP,is_A_all,&msolv_ctx->is_B);CHKERRQ(ierr);
1088         ierr = VecScatterCreate(vec1_B,msolv_ctx->is_B,msolv_ctx->sol_B,NULL,&msolv_ctx->correction_scatter_B);CHKERRQ(ierr);
1089         ierr = PetscObjectReference((PetscObject)is_A_all);CHKERRQ(ierr);
1090         msolv_ctx->is_R = is_A_all;
1091       } else {
1092         IS              is_B_all;
1093         const PetscInt* idxs;
1094         PetscInt        dual,n_v,n;
1095 
1096         ierr = ISGetLocalSize(sub_schurs->is_vertices,&n_v);CHKERRQ(ierr);
1097         dual = size_schur - n_v;
1098         ierr = ISGetLocalSize(is_A_all,&n);CHKERRQ(ierr);
1099         ierr = ISGetIndices(is_A_all,&idxs);CHKERRQ(ierr);
1100         ierr = ISCreateGeneral(PetscObjectComm((PetscObject)is_A_all),dual,idxs+n_I,PETSC_COPY_VALUES,&is_B_all);CHKERRQ(ierr);
1101         ierr = ISGlobalToLocalMappingApplyIS(sub_schurs->BtoNmap,IS_GTOLM_DROP,is_B_all,&msolv_ctx->is_B);CHKERRQ(ierr);
1102         ierr = ISDestroy(&is_B_all);CHKERRQ(ierr);
1103         ierr = ISCreateStride(PetscObjectComm((PetscObject)is_A_all),dual,0,1,&is_B_all);CHKERRQ(ierr);
1104         ierr = VecScatterCreate(vec1_B,msolv_ctx->is_B,msolv_ctx->sol_B,is_B_all,&msolv_ctx->correction_scatter_B);CHKERRQ(ierr);
1105         ierr = ISDestroy(&is_B_all);CHKERRQ(ierr);
1106         ierr = ISCreateGeneral(PetscObjectComm((PetscObject)is_A_all),n-n_v,idxs,PETSC_COPY_VALUES,&msolv_ctx->is_R);CHKERRQ(ierr);
1107         ierr = ISRestoreIndices(is_A_all,&idxs);CHKERRQ(ierr);
1108       }
1109       ierr = ISGetLocalSize(msolv_ctx->is_R,&n_R);CHKERRQ(ierr);
1110       ierr = MatCreateSeqAIJ(PETSC_COMM_SELF,n_R,n_R,0,NULL,&Afake);CHKERRQ(ierr);
1111       ierr = PCSetOperators(msolv_ctx->correction_solver,Afake,Afake);CHKERRQ(ierr);
1112       ierr = MatDestroy(&Afake);CHKERRQ(ierr);
1113       ierr = VecDestroy(&vec1_B);CHKERRQ(ierr);
1114 
1115       /* communicate benign info to solver context */
1116       if (benign_n) {
1117         PetscScalar *array;
1118 
1119         msolv_ctx->benign_n = benign_n;
1120         msolv_ctx->benign_zerodiag_subs = is_p_r;
1121         ierr = PetscMalloc1(benign_n,&msolv_ctx->benign_save_vals);CHKERRQ(ierr);
1122         msolv_ctx->benign_csAIB = cs_AIB_mat;
1123         ierr = MatCreateVecs(cs_AIB_mat,&msolv_ctx->benign_corr_work,NULL);CHKERRQ(ierr);
1124         ierr = VecGetArray(msolv_ctx->benign_corr_work,&array);CHKERRQ(ierr);
1125         ierr = VecCreateSeqWithArray(PETSC_COMM_SELF,1,size_schur,array,&msolv_ctx->benign_dummy_schur_vec);CHKERRQ(ierr);
1126         ierr = VecRestoreArray(msolv_ctx->benign_corr_work,&array);CHKERRQ(ierr);
1127         msolv_ctx->benign_AIIm1ones = benign_AIIm1_ones_mat;
1128       }
1129     }
1130     ierr = MatDestroy(&A);CHKERRQ(ierr);
1131     ierr = ISDestroy(&is_A_all);CHKERRQ(ierr);
1132 
1133     /* Work arrays */
1134     ierr = PetscMalloc2(max_subset_size,&dummy_idx,max_subset_size*max_subset_size,&work);CHKERRQ(ierr);
1135 
1136     /* matrices for deluxe scaling and adaptive selection */
1137     if (!sub_schurs->sum_S_Ej_all) {
1138       ierr = MatCreate(PETSC_COMM_SELF,&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
1139       ierr = MatSetSizes(sub_schurs->sum_S_Ej_all,PETSC_DECIDE,PETSC_DECIDE,size_active_schur,size_active_schur);CHKERRQ(ierr);
1140       ierr = MatSetType(sub_schurs->sum_S_Ej_all,MATAIJ);CHKERRQ(ierr);
1141       ierr = MatSeqAIJSetPreallocation(sub_schurs->sum_S_Ej_all,0,nnz);CHKERRQ(ierr);
1142     }
1143     if (compute_Stilda) {
1144       if (!sub_schurs->sum_S_Ej_tilda_all) {
1145         ierr = MatDuplicate(sub_schurs->sum_S_Ej_all,MAT_SHARE_NONZERO_PATTERN,&sub_schurs->sum_S_Ej_tilda_all);CHKERRQ(ierr);
1146       }
1147       if (!sub_schurs->sum_S_Ej_inv_all && deluxe) {
1148         ierr = MatDuplicate(sub_schurs->sum_S_Ej_all,MAT_SHARE_NONZERO_PATTERN,&sub_schurs->sum_S_Ej_inv_all);CHKERRQ(ierr);
1149       }
1150     }
1151 
1152     /* S_Ej_all */
1153     cum = cum2 = 0;
1154     ierr = MatDenseGetArray(S_all,&S_data);CHKERRQ(ierr);
1155     for (i=0;i<sub_schurs->n_subs;i++) {
1156       PetscInt j;
1157 
1158       /* get S_E */
1159       ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
1160       if (S_lower_triangular) { /* I need to expand the upper triangular data (column oriented) */
1161         PetscInt k;
1162         for (k=0;k<subset_size;k++) {
1163           for (j=k;j<subset_size;j++) {
1164             work[k*subset_size+j] = S_data[cum2+k*size_schur+j];
1165             work[j*subset_size+k] = PetscConj(S_data[cum2+k*size_schur+j]);
1166           }
1167         }
1168       } else { /* just copy to workspace */
1169         PetscInt k;
1170         for (k=0;k<subset_size;k++) {
1171           for (j=0;j<subset_size;j++) {
1172             work[k*subset_size+j] = S_data[cum2+k*size_schur+j];
1173           }
1174         }
1175       }
1176       /* insert S_E values */
1177       for (j=0;j<subset_size;j++) dummy_idx[j] = cum+j;
1178       if (sub_schurs->change) {
1179         Mat            change_sub,SEj,T;
1180 
1181         /* change basis */
1182         ierr = KSPGetOperators(sub_schurs->change[i],&change_sub,NULL);CHKERRQ(ierr);
1183         ierr = MatCreateSeqDense(PETSC_COMM_SELF,subset_size,subset_size,work,&SEj);CHKERRQ(ierr);
1184         if (!sub_schurs->change_with_qr) { /* currently there's no support for PtAP with P SeqAIJ */
1185           Mat T2;
1186           ierr = MatTransposeMatMult(change_sub,SEj,MAT_INITIAL_MATRIX,1.0,&T2);CHKERRQ(ierr);
1187           ierr = MatMatMult(T2,change_sub,MAT_INITIAL_MATRIX,1.0,&T);CHKERRQ(ierr);
1188           ierr = MatConvert(T,MATSEQDENSE,MAT_INPLACE_MATRIX,&T);CHKERRQ(ierr);
1189           ierr = MatDestroy(&T2);CHKERRQ(ierr);
1190         } else {
1191           ierr = MatPtAP(SEj,change_sub,MAT_INITIAL_MATRIX,1.0,&T);CHKERRQ(ierr);
1192         }
1193         ierr = MatCopy(T,SEj,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
1194         ierr = MatDestroy(&T);CHKERRQ(ierr);
1195         ierr = MatZeroRowsColumnsIS(SEj,sub_schurs->change_primal_sub[i],1.0,NULL,NULL);CHKERRQ(ierr);
1196         ierr = MatDestroy(&SEj);CHKERRQ(ierr);
1197       }
1198       if (deluxe) {
1199         ierr = MatSetValues(sub_schurs->S_Ej_all,subset_size,dummy_idx,subset_size,dummy_idx,work,INSERT_VALUES);CHKERRQ(ierr);
1200         /* if adaptivity is requested, invert S_E blocks */
1201         if (compute_Stilda) {
1202           ierr = PetscBLASIntCast(subset_size,&B_N);CHKERRQ(ierr);
1203           ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
1204           if (!use_getr) { /* TODO add sytrf/i for symmetric non hermitian */
1205             PetscInt k;
1206             PetscStackCallBLAS("LAPACKpotrf",LAPACKpotrf_("L",&B_N,work,&B_N,&B_ierr));
1207             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRF Lapack routine %d",(int)B_ierr);
1208             PetscStackCallBLAS("LAPACKpotri",LAPACKpotri_("L",&B_N,work,&B_N,&B_ierr));
1209             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRI Lapack routine %d",(int)B_ierr);
1210             for (k=0;k<subset_size;k++) {
1211               for (j=k;j<subset_size;j++) {
1212                 work[j*subset_size+k] = work[k*subset_size+j];
1213               }
1214             }
1215           } else {
1216             PetscStackCallBLAS("LAPACKgetrf",LAPACKgetrf_(&B_N,&B_N,work,&B_N,pivots,&B_ierr));
1217             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRF Lapack routine %d",(int)B_ierr);
1218             PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,work,&B_N,pivots,Bwork,&B_lwork,&B_ierr));
1219             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRI Lapack routine %d",(int)B_ierr);
1220           }
1221           ierr = PetscFPTrapPop();CHKERRQ(ierr);
1222           ierr = MatSetValues(sub_schurs->sum_S_Ej_inv_all,subset_size,dummy_idx,subset_size,dummy_idx,work,INSERT_VALUES);CHKERRQ(ierr);
1223         }
1224       } else if (compute_Stilda) { /* not using deluxe */
1225         Mat         SEj;
1226         Vec         D;
1227         PetscScalar *array;
1228 
1229         ierr = MatCreateSeqDense(PETSC_COMM_SELF,subset_size,subset_size,work,&SEj);CHKERRQ(ierr);
1230         ierr = VecGetArray(Dall,&array);CHKERRQ(ierr);
1231         ierr = VecCreateSeqWithArray(PETSC_COMM_SELF,1,subset_size,array+cum,&D);CHKERRQ(ierr);
1232         ierr = VecRestoreArray(Dall,&array);CHKERRQ(ierr);
1233         ierr = VecShift(D,-1.);CHKERRQ(ierr);
1234         ierr = MatDiagonalScale(SEj,D,D);CHKERRQ(ierr);
1235         ierr = MatDestroy(&SEj);CHKERRQ(ierr);
1236         ierr = VecDestroy(&D);CHKERRQ(ierr);
1237         ierr = MatSetValues(sub_schurs->S_Ej_all,subset_size,dummy_idx,subset_size,dummy_idx,work,INSERT_VALUES);CHKERRQ(ierr);
1238       }
1239       cum += subset_size;
1240       cum2 += subset_size*(size_schur + 1);
1241     }
1242     ierr = MatDenseRestoreArray(S_all,&S_data);CHKERRQ(ierr);
1243 
1244     if (solver_S) {
1245       ierr = MatFactorRestoreSchurComplement(F,&S_all,MAT_FACTOR_SCHUR_UNFACTORED);CHKERRQ(ierr);
1246     }
1247 
1248     schur_factor = NULL;
1249     if (compute_Stilda && size_active_schur) {
1250 
1251       if (sub_schurs->n_subs == 1 && size_schur == size_active_schur && deluxe) { /* we already computed the inverse */
1252         PetscInt j;
1253         for (j=0;j<size_schur;j++) dummy_idx[j] = j;
1254         ierr = MatSetValues(sub_schurs->sum_S_Ej_tilda_all,size_schur,dummy_idx,size_schur,dummy_idx,work,INSERT_VALUES);CHKERRQ(ierr);
1255       } else {
1256         Mat S_all_inv=NULL;
1257         if (solver_S) {
1258           /* for adaptive selection we need S^-1; for solver reusage we need S_\Delta\Delta^-1.
1259              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 */
1260           if (factor_workaround) {/* invert without calling MatFactorInvertSchurComplement, since we are hacking */
1261             PetscScalar *data;
1262             PetscInt     nd = 0;
1263 
1264             if (!sub_schurs->is_posdef) {
1265               SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Factor update not yet implemented for non SPD matrices");
1266             }
1267             ierr = MatFactorGetSchurComplement(F,&S_all_inv,NULL);CHKERRQ(ierr);
1268             ierr = MatDenseGetArray(S_all_inv,&data);CHKERRQ(ierr);
1269             if (sub_schurs->is_dir) { /* dirichlet dofs could have different scalings */
1270               ierr = ISGetLocalSize(sub_schurs->is_dir,&nd);CHKERRQ(ierr);
1271             }
1272 
1273             /* factor and invert activedofs and vertices (dirichlet dofs does not contribute) */
1274             if (schur_has_vertices) {
1275               Mat          M;
1276               PetscScalar *tdata;
1277               PetscInt     nv = 0, news;
1278 
1279               ierr = ISGetLocalSize(sub_schurs->is_vertices,&nv);CHKERRQ(ierr);
1280               news = size_active_schur + nv;
1281               ierr = PetscCalloc1(news*news,&tdata);CHKERRQ(ierr);
1282               for (i=0;i<size_active_schur;i++) {
1283                 ierr = PetscMemcpy(tdata+i*(news+1),data+i*(size_schur+1),(size_active_schur-i)*sizeof(PetscScalar));CHKERRQ(ierr);
1284                 ierr = PetscMemcpy(tdata+i*(news+1)+size_active_schur-i,data+i*size_schur+size_active_schur+nd,nv*sizeof(PetscScalar));CHKERRQ(ierr);
1285               }
1286               for (i=0;i<nv;i++) {
1287                 PetscInt k = i+size_active_schur;
1288                 ierr = PetscMemcpy(tdata+k*(news+1),data+(k+nd)*(size_schur+1),(nv-i)*sizeof(PetscScalar));CHKERRQ(ierr);
1289               }
1290 
1291               ierr = MatCreateSeqDense(PETSC_COMM_SELF,news,news,tdata,&M);CHKERRQ(ierr);
1292               ierr = MatSetOption(M,MAT_SPD,PETSC_TRUE);CHKERRQ(ierr);
1293               ierr = MatCholeskyFactor(M,NULL,NULL);CHKERRQ(ierr);
1294               /* save the factors */
1295               cum = 0;
1296               ierr = PetscMalloc1((size_active_schur*(size_active_schur +1))/2+nd,&schur_factor);CHKERRQ(ierr);
1297               for (i=0;i<size_active_schur;i++) {
1298                 ierr = PetscMemcpy(schur_factor+cum,tdata+i*(news+1),(size_active_schur-i)*sizeof(PetscScalar));CHKERRQ(ierr);
1299                 cum += size_active_schur - i;
1300               }
1301               for (i=0;i<nd;i++) schur_factor[cum+i] = PetscSqrtReal(PetscRealPart(data[(i+size_active_schur)*(size_schur+1)]));
1302               ierr = MatSeqDenseInvertFactors_Private(M);CHKERRQ(ierr);
1303               /* move back just the active dofs to the Schur complement */
1304               for (i=0;i<size_active_schur;i++) {
1305                 ierr = PetscMemcpy(data+i*size_schur,tdata+i*news,size_active_schur*sizeof(PetscScalar));CHKERRQ(ierr);
1306               }
1307               ierr = PetscFree(tdata);CHKERRQ(ierr);
1308               ierr = MatDestroy(&M);CHKERRQ(ierr);
1309             } else { /* we can factorize and invert just the activedofs */
1310               Mat M;
1311 
1312               ierr = MatCreateSeqDense(PETSC_COMM_SELF,size_active_schur,size_active_schur,data,&M);CHKERRQ(ierr);
1313               ierr = MatSeqDenseSetLDA(M,size_schur);CHKERRQ(ierr);
1314               ierr = MatSetOption(M,MAT_SPD,PETSC_TRUE);CHKERRQ(ierr);
1315               ierr = MatCholeskyFactor(M,NULL,NULL);CHKERRQ(ierr);
1316               ierr = MatSeqDenseInvertFactors_Private(M);CHKERRQ(ierr);
1317               ierr = MatDestroy(&M);CHKERRQ(ierr);
1318               for (i=0;i<nd;i++) data[(i+size_active_schur)*(size_schur+1)] = 1.0/data[(i+size_active_schur)*(size_schur+1)];
1319             }
1320             ierr = MatDenseRestoreArray(S_all_inv,&data);CHKERRQ(ierr);
1321           } else { /* use MatFactor calls to invert S */
1322             ierr = MatFactorInvertSchurComplement(F);CHKERRQ(ierr);
1323             ierr = MatFactorGetSchurComplement(F,&S_all_inv,NULL);CHKERRQ(ierr);
1324           }
1325         } else { /* we need to invert explicitly since we are not using MatFactor for S */
1326           ierr = PetscObjectReference((PetscObject)S_all);CHKERRQ(ierr);
1327           S_all_inv = S_all;
1328           ierr = MatDenseGetArray(S_all_inv,&S_data);CHKERRQ(ierr);
1329           ierr = PetscBLASIntCast(size_schur,&B_N);CHKERRQ(ierr);
1330           ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
1331           if (!use_getr) { /* TODO add sytrf/i for symmetric non hermitian */
1332             PetscStackCallBLAS("LAPACKpotrf",LAPACKpotrf_("L",&B_N,S_data,&B_N,&B_ierr));
1333             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRF Lapack routine %d",(int)B_ierr);
1334             PetscStackCallBLAS("LAPACKpotri",LAPACKpotri_("L",&B_N,S_data,&B_N,&B_ierr));
1335             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRI Lapack routine %d",(int)B_ierr);
1336           } else {
1337             PetscStackCallBLAS("LAPACKgetrf",LAPACKgetrf_(&B_N,&B_N,S_data,&B_N,pivots,&B_ierr));
1338             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRF Lapack routine %d",(int)B_ierr);
1339             PetscStackCallBLAS("LAPACKgetri",LAPACKgetri_(&B_N,S_data,&B_N,pivots,Bwork,&B_lwork,&B_ierr));
1340             if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in GETRI Lapack routine %d",(int)B_ierr);
1341           }
1342           ierr = PetscFPTrapPop();CHKERRQ(ierr);
1343           ierr = MatDenseRestoreArray(S_all_inv,&S_data);CHKERRQ(ierr);
1344         }
1345         /* S_Ej_tilda_all */
1346         cum = cum2 = 0;
1347         ierr = MatDenseGetArray(S_all_inv,&S_data);CHKERRQ(ierr);
1348         for (i=0;i<sub_schurs->n_subs;i++) {
1349           PetscInt j;
1350 
1351           ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
1352           /* get (St^-1)_E */
1353           /* Unless we are changing the variables, I don't need to expand to upper triangular since St^-1
1354              will be properly accessed later during adaptive selection */
1355           if (S_lower_triangular) {
1356             PetscInt k;
1357             if (sub_schurs->change) {
1358               for (k=0;k<subset_size;k++) {
1359                 for (j=k;j<subset_size;j++) {
1360                   work[k*subset_size+j] = S_data[cum2+k*size_schur+j];
1361                   work[j*subset_size+k] = work[k*subset_size+j];
1362                 }
1363               }
1364             } else {
1365               for (k=0;k<subset_size;k++) {
1366                 for (j=k;j<subset_size;j++) {
1367                   work[k*subset_size+j] = S_data[cum2+k*size_schur+j];
1368                 }
1369               }
1370             }
1371           } else {
1372             PetscInt k;
1373             for (k=0;k<subset_size;k++) {
1374               for (j=0;j<subset_size;j++) {
1375                 work[k*subset_size+j] = S_data[cum2+k*size_schur+j];
1376               }
1377             }
1378           }
1379           if (sub_schurs->change) {
1380             Mat change_sub,SEj,T;
1381 
1382             /* change basis */
1383             ierr = KSPGetOperators(sub_schurs->change[i],&change_sub,NULL);CHKERRQ(ierr);
1384             ierr = MatCreateSeqDense(PETSC_COMM_SELF,subset_size,subset_size,work,&SEj);CHKERRQ(ierr);
1385             if (!sub_schurs->change_with_qr) { /* currently there's no support for PtAP with P SeqAIJ */
1386               Mat T2;
1387               ierr = MatTransposeMatMult(change_sub,SEj,MAT_INITIAL_MATRIX,1.0,&T2);CHKERRQ(ierr);
1388               ierr = MatMatMult(T2,change_sub,MAT_INITIAL_MATRIX,1.0,&T);CHKERRQ(ierr);
1389               ierr = MatDestroy(&T2);CHKERRQ(ierr);
1390               ierr = MatConvert(T,MATSEQDENSE,MAT_INPLACE_MATRIX,&T);CHKERRQ(ierr);
1391             } else {
1392               ierr = MatPtAP(SEj,change_sub,MAT_INITIAL_MATRIX,1.0,&T);CHKERRQ(ierr);
1393             }
1394             ierr = MatCopy(T,SEj,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
1395             ierr = MatDestroy(&T);CHKERRQ(ierr);
1396             /* set diagonal entry to a very large value to pick the basis we are eliminating as the first eigenvectors with adaptive selection */
1397             ierr = MatZeroRowsColumnsIS(SEj,sub_schurs->change_primal_sub[i],1./PETSC_SMALL,NULL,NULL);CHKERRQ(ierr);
1398             ierr = MatDestroy(&SEj);CHKERRQ(ierr);
1399           }
1400           for (j=0;j<subset_size;j++) dummy_idx[j] = cum+j;
1401           ierr = MatSetValues(sub_schurs->sum_S_Ej_tilda_all,subset_size,dummy_idx,subset_size,dummy_idx,work,INSERT_VALUES);CHKERRQ(ierr);
1402           cum += subset_size;
1403           cum2 += subset_size*(size_schur + 1);
1404         }
1405         ierr = MatDenseRestoreArray(S_all_inv,&S_data);CHKERRQ(ierr);
1406         if (solver_S) {
1407           if (schur_has_vertices) {
1408             ierr = MatFactorRestoreSchurComplement(F,&S_all_inv,MAT_FACTOR_SCHUR_FACTORED);CHKERRQ(ierr);
1409           } else {
1410             ierr = MatFactorRestoreSchurComplement(F,&S_all_inv,MAT_FACTOR_SCHUR_INVERTED);CHKERRQ(ierr);
1411           }
1412         }
1413         ierr = MatDestroy(&S_all_inv);CHKERRQ(ierr);
1414       }
1415 
1416       /* move back factors if needed */
1417       if (schur_has_vertices) {
1418         Mat      S_tmp;
1419         PetscInt nd = 0;
1420 
1421         if (!solver_S) {
1422           SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"This should not happen");
1423         }
1424         ierr = MatFactorGetSchurComplement(F,&S_tmp,NULL);CHKERRQ(ierr);
1425         if (sub_schurs->is_posdef) {
1426           PetscScalar *data;
1427 
1428           ierr = MatDenseGetArray(S_tmp,&data);CHKERRQ(ierr);
1429           ierr = PetscMemzero(data,size_schur*size_schur*sizeof(PetscScalar));CHKERRQ(ierr);
1430 
1431           if (S_lower_triangular) {
1432             cum = 0;
1433             for (i=0;i<size_active_schur;i++) {
1434               ierr = PetscMemcpy(data+i*(size_schur+1),schur_factor+cum,(size_active_schur-i)*sizeof(PetscScalar));CHKERRQ(ierr);
1435               cum += size_active_schur-i;
1436 	    }
1437           } else {
1438             ierr = PetscMemcpy(data,schur_factor,size_schur*size_schur*sizeof(PetscScalar));CHKERRQ(ierr);
1439           }
1440           if (sub_schurs->is_dir) {
1441             ierr = ISGetLocalSize(sub_schurs->is_dir,&nd);CHKERRQ(ierr);
1442 	    for (i=0;i<nd;i++) {
1443 	      data[(i+size_active_schur)*(size_schur+1)] = schur_factor[cum+i];
1444 	    }
1445           }
1446           /* workaround: since I cannot modify the matrices used inside the solvers for the forward and backward substitutions,
1447              set the diagonal entry of the Schur factor to a very large value */
1448           for (i=size_active_schur+nd;i<size_schur;i++) {
1449             data[i*(size_schur+1)] = infty;
1450           }
1451           ierr = MatDenseRestoreArray(S_tmp,&data);CHKERRQ(ierr);
1452         } else {
1453           SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Factor update not yet implemented for non SPD matrices");
1454         }
1455         ierr = MatFactorRestoreSchurComplement(F,&S_tmp,MAT_FACTOR_SCHUR_FACTORED);CHKERRQ(ierr);
1456       }
1457     } else if (factor_workaround) { /* we need to eliminate any unneeded coupling */
1458       PetscScalar *data;
1459       PetscInt    nd = 0;
1460 
1461       if (sub_schurs->is_dir) { /* dirichlet dofs could have different scalings */
1462         ierr = ISGetLocalSize(sub_schurs->is_dir,&nd);CHKERRQ(ierr);
1463       }
1464       ierr = MatFactorGetSchurComplement(F,&S_all,NULL);CHKERRQ(ierr);
1465       ierr = MatDenseGetArray(S_all,&data);CHKERRQ(ierr);
1466       for (i=0;i<size_active_schur;i++) {
1467         ierr = PetscMemzero(data+i*size_schur+size_active_schur,(size_schur-size_active_schur)*sizeof(PetscScalar));CHKERRQ(ierr);
1468       }
1469       for (i=size_active_schur+nd;i<size_schur;i++) {
1470         ierr = PetscMemzero(data+i*size_schur+size_active_schur,(size_schur-size_active_schur)*sizeof(PetscScalar));CHKERRQ(ierr);
1471         data[i*(size_schur+1)] = infty;
1472       }
1473       ierr = MatDenseRestoreArray(S_all,&data);CHKERRQ(ierr);
1474       ierr = MatFactorRestoreSchurComplement(F,&S_all,MAT_FACTOR_SCHUR_UNFACTORED);CHKERRQ(ierr);
1475     }
1476     ierr = PetscFree2(dummy_idx,work);CHKERRQ(ierr);
1477     ierr = PetscFree(schur_factor);CHKERRQ(ierr);
1478     ierr = VecDestroy(&Dall);CHKERRQ(ierr);
1479   }
1480   ierr = PetscFree(nnz);CHKERRQ(ierr);
1481   ierr = MatDestroy(&F);CHKERRQ(ierr);
1482   ierr = ISDestroy(&is_I_layer);CHKERRQ(ierr);
1483   ierr = MatDestroy(&S_all);CHKERRQ(ierr);
1484   ierr = MatDestroy(&A_BB);CHKERRQ(ierr);
1485   ierr = MatDestroy(&A_IB);CHKERRQ(ierr);
1486   ierr = MatDestroy(&A_BI);CHKERRQ(ierr);
1487   ierr = MatAssemblyBegin(sub_schurs->S_Ej_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1488   ierr = MatAssemblyEnd(sub_schurs->S_Ej_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1489   if (compute_Stilda) {
1490     ierr = MatAssemblyBegin(sub_schurs->sum_S_Ej_tilda_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1491     ierr = MatAssemblyEnd(sub_schurs->sum_S_Ej_tilda_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1492     if (deluxe) {
1493       ierr = MatAssemblyBegin(sub_schurs->sum_S_Ej_inv_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1494       ierr = MatAssemblyEnd(sub_schurs->sum_S_Ej_inv_all,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1495     }
1496   }
1497 
1498   /* Global matrix of all assembled Schur on subsets */
1499   ierr = MatISSetLocalMat(work_mat,sub_schurs->S_Ej_all);CHKERRQ(ierr);
1500   ierr = MatISSetMPIXAIJPreallocation_Private(work_mat,global_schur_subsets,PETSC_TRUE);CHKERRQ(ierr);
1501   ierr = MatISGetMPIXAIJ(work_mat,MAT_REUSE_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
1502 
1503   /* Get local part of (\sum_j S_Ej) */
1504   ierr = MatCreateSubMatrices(global_schur_subsets,1,&all_subsets_n,&all_subsets_n,MAT_INITIAL_MATRIX,&submats);CHKERRQ(ierr);
1505   ierr = MatCopy(submats[0],sub_schurs->sum_S_Ej_all,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
1506 
1507   /* Get local part of (\sum_j S^-1_Ej) (\sum_j St^-1_Ej) */
1508   if (compute_Stilda) {
1509     ierr = MatISSetLocalMat(work_mat,sub_schurs->sum_S_Ej_tilda_all);CHKERRQ(ierr);
1510     ierr = MatISGetMPIXAIJ(work_mat,MAT_REUSE_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
1511     ierr = MatCreateSubMatrices(global_schur_subsets,1,&all_subsets_n,&all_subsets_n,MAT_REUSE_MATRIX,&submats);CHKERRQ(ierr);
1512     ierr = MatCopy(submats[0],sub_schurs->sum_S_Ej_tilda_all,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
1513     if (deluxe) {
1514       ierr = MatISSetLocalMat(work_mat,sub_schurs->sum_S_Ej_inv_all);CHKERRQ(ierr);
1515       ierr = MatISGetMPIXAIJ(work_mat,MAT_REUSE_MATRIX,&global_schur_subsets);CHKERRQ(ierr);
1516       ierr = MatCreateSubMatrices(global_schur_subsets,1,&all_subsets_n,&all_subsets_n,MAT_REUSE_MATRIX,&submats);CHKERRQ(ierr);
1517       ierr = MatCopy(submats[0],sub_schurs->sum_S_Ej_inv_all,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
1518     } else {
1519       PetscScalar *array;
1520       PetscInt    cum;
1521 
1522       ierr = MatSeqAIJGetArray(sub_schurs->sum_S_Ej_tilda_all,&array);CHKERRQ(ierr);
1523       cum = 0;
1524       for (i=0;i<sub_schurs->n_subs;i++) {
1525         ierr = ISGetLocalSize(sub_schurs->is_subs[i],&subset_size);CHKERRQ(ierr);
1526         ierr = PetscBLASIntCast(subset_size,&B_N);CHKERRQ(ierr);
1527         ierr = PetscFPTrapPush(PETSC_FP_TRAP_OFF);CHKERRQ(ierr);
1528         PetscStackCallBLAS("LAPACKpotrf",LAPACKpotrf_("L",&B_N,array+cum,&B_N,&B_ierr));
1529         if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRF Lapack routine %d",(int)B_ierr);
1530         PetscStackCallBLAS("LAPACKpotri",LAPACKpotri_("L",&B_N,array+cum,&B_N,&B_ierr));
1531         if (B_ierr) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Error in POTRI Lapack routine %d",(int)B_ierr);
1532         ierr = PetscFPTrapPop();CHKERRQ(ierr);
1533         cum += subset_size*subset_size;
1534       }
1535       ierr = MatSeqAIJRestoreArray(sub_schurs->sum_S_Ej_tilda_all,&array);CHKERRQ(ierr);
1536       ierr = PetscObjectReference((PetscObject)sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
1537       ierr = MatDestroy(&sub_schurs->sum_S_Ej_inv_all);CHKERRQ(ierr);
1538       sub_schurs->sum_S_Ej_inv_all = sub_schurs->sum_S_Ej_all;
1539     }
1540   }
1541   ierr = MatDestroySubMatrices(1,&submats);CHKERRQ(ierr);
1542 
1543   /* free workspace */
1544   ierr = PetscFree(submats);CHKERRQ(ierr);
1545   ierr = PetscFree2(Bwork,pivots);CHKERRQ(ierr);
1546   ierr = MatDestroy(&global_schur_subsets);CHKERRQ(ierr);
1547   ierr = MatDestroy(&work_mat);CHKERRQ(ierr);
1548   ierr = ISDestroy(&all_subsets_n);CHKERRQ(ierr);
1549   ierr = PetscCommDestroy(&comm_n);CHKERRQ(ierr);
1550   PetscFunctionReturn(0);
1551 }
1552 
1553 PetscErrorCode PCBDDCSubSchursInit(PCBDDCSubSchurs sub_schurs, IS is_I, IS is_B, PCBDDCGraph graph, ISLocalToGlobalMapping BtoNmap, PetscBool copycc)
1554 {
1555   IS              *faces,*edges,*all_cc,vertices;
1556   PetscInt        i,n_faces,n_edges,n_all_cc;
1557   PetscBool       is_sorted;
1558   PetscErrorCode  ierr;
1559 
1560   PetscFunctionBegin;
1561   ierr = ISSorted(is_I,&is_sorted);CHKERRQ(ierr);
1562   if (!is_sorted) SETERRQ(PetscObjectComm((PetscObject)is_I),PETSC_ERR_PLIB,"IS for I dofs should be shorted");
1563   ierr = ISSorted(is_B,&is_sorted);CHKERRQ(ierr);
1564   if (!is_sorted) SETERRQ(PetscObjectComm((PetscObject)is_B),PETSC_ERR_PLIB,"IS for B dofs should be shorted");
1565 
1566   /* reset any previous data */
1567   ierr = PCBDDCSubSchursReset(sub_schurs);CHKERRQ(ierr);
1568 
1569   /* get index sets for faces and edges (already sorted by global ordering) */
1570   ierr = PCBDDCGraphGetCandidatesIS(graph,&n_faces,&faces,&n_edges,&edges,&vertices);CHKERRQ(ierr);
1571   n_all_cc = n_faces+n_edges;
1572   ierr = PetscBTCreate(n_all_cc,&sub_schurs->is_edge);CHKERRQ(ierr);
1573   ierr = PetscMalloc1(n_all_cc,&all_cc);CHKERRQ(ierr);
1574   for (i=0;i<n_faces;i++) {
1575     if (copycc) {
1576       ierr = ISDuplicate(faces[i],&all_cc[i]);CHKERRQ(ierr);
1577     } else {
1578       ierr = PetscObjectReference((PetscObject)faces[i]);CHKERRQ(ierr);
1579       all_cc[i] = faces[i];
1580     }
1581   }
1582   for (i=0;i<n_edges;i++) {
1583     if (copycc) {
1584       ierr = ISDuplicate(edges[i],&all_cc[n_faces+i]);CHKERRQ(ierr);
1585     } else {
1586       ierr = PetscObjectReference((PetscObject)edges[i]);CHKERRQ(ierr);
1587       all_cc[n_faces+i] = edges[i];
1588     }
1589     ierr = PetscBTSet(sub_schurs->is_edge,n_faces+i);CHKERRQ(ierr);
1590   }
1591   ierr = PetscObjectReference((PetscObject)vertices);CHKERRQ(ierr);
1592   sub_schurs->is_vertices = vertices;
1593   ierr = PCBDDCGraphRestoreCandidatesIS(graph,&n_faces,&faces,&n_edges,&edges,&vertices);CHKERRQ(ierr);
1594   sub_schurs->is_dir = NULL;
1595   ierr = PCBDDCGraphGetDirichletDofsB(graph,&sub_schurs->is_dir);CHKERRQ(ierr);
1596 
1597   /* Determine if MatFactor can be used */
1598   sub_schurs->schur_explicit = PETSC_FALSE;
1599 #if defined(PETSC_HAVE_MUMPS)
1600   sub_schurs->schur_explicit = PETSC_TRUE;
1601 #endif
1602 #if defined(PETSC_HAVE_MKL_PARDISO)
1603   sub_schurs->schur_explicit = PETSC_TRUE;
1604 #endif
1605 
1606   ierr = PetscObjectReference((PetscObject)is_I);CHKERRQ(ierr);
1607   sub_schurs->is_I = is_I;
1608   ierr = PetscObjectReference((PetscObject)is_B);CHKERRQ(ierr);
1609   sub_schurs->is_B = is_B;
1610   ierr = PetscObjectReference((PetscObject)graph->l2gmap);CHKERRQ(ierr);
1611   sub_schurs->l2gmap = graph->l2gmap;
1612   ierr = PetscObjectReference((PetscObject)BtoNmap);CHKERRQ(ierr);
1613   sub_schurs->BtoNmap = BtoNmap;
1614   sub_schurs->n_subs = n_all_cc;
1615   sub_schurs->is_subs = all_cc;
1616   if (!sub_schurs->schur_explicit) { /* sort by local ordering if we are not using MatFactor */
1617     for (i=0;i<sub_schurs->n_subs;i++) {
1618       ierr = ISSort(sub_schurs->is_subs[i]);CHKERRQ(ierr);
1619     }
1620   }
1621   sub_schurs->S_Ej_all = NULL;
1622   sub_schurs->sum_S_Ej_all = NULL;
1623   sub_schurs->sum_S_Ej_inv_all = NULL;
1624   sub_schurs->sum_S_Ej_tilda_all = NULL;
1625   sub_schurs->is_Ej_all = NULL;
1626   PetscFunctionReturn(0);
1627 }
1628 
1629 PetscErrorCode PCBDDCSubSchursCreate(PCBDDCSubSchurs *sub_schurs)
1630 {
1631   PCBDDCSubSchurs schurs_ctx;
1632   PetscErrorCode  ierr;
1633 
1634   PetscFunctionBegin;
1635   ierr = PetscNew(&schurs_ctx);CHKERRQ(ierr);
1636   schurs_ctx->n_subs = 0;
1637   *sub_schurs = schurs_ctx;
1638   PetscFunctionReturn(0);
1639 }
1640 
1641 PetscErrorCode PCBDDCSubSchursReset(PCBDDCSubSchurs sub_schurs)
1642 {
1643   PetscInt       i;
1644   PetscErrorCode ierr;
1645 
1646   PetscFunctionBegin;
1647   if (!sub_schurs) PetscFunctionReturn(0);
1648   ierr = MatDestroy(&sub_schurs->A);CHKERRQ(ierr);
1649   ierr = MatDestroy(&sub_schurs->S);CHKERRQ(ierr);
1650   ierr = ISDestroy(&sub_schurs->is_I);CHKERRQ(ierr);
1651   ierr = ISDestroy(&sub_schurs->is_B);CHKERRQ(ierr);
1652   ierr = ISLocalToGlobalMappingDestroy(&sub_schurs->l2gmap);CHKERRQ(ierr);
1653   ierr = ISLocalToGlobalMappingDestroy(&sub_schurs->BtoNmap);CHKERRQ(ierr);
1654   ierr = MatDestroy(&sub_schurs->S_Ej_all);CHKERRQ(ierr);
1655   ierr = MatDestroy(&sub_schurs->sum_S_Ej_all);CHKERRQ(ierr);
1656   ierr = MatDestroy(&sub_schurs->sum_S_Ej_inv_all);CHKERRQ(ierr);
1657   ierr = MatDestroy(&sub_schurs->sum_S_Ej_tilda_all);CHKERRQ(ierr);
1658   ierr = ISDestroy(&sub_schurs->is_Ej_all);CHKERRQ(ierr);
1659   ierr = ISDestroy(&sub_schurs->is_vertices);CHKERRQ(ierr);
1660   ierr = ISDestroy(&sub_schurs->is_dir);CHKERRQ(ierr);
1661   ierr = PetscBTDestroy(&sub_schurs->is_edge);CHKERRQ(ierr);
1662   for (i=0;i<sub_schurs->n_subs;i++) {
1663     ierr = ISDestroy(&sub_schurs->is_subs[i]);CHKERRQ(ierr);
1664   }
1665   if (sub_schurs->n_subs) {
1666     ierr = PetscFree(sub_schurs->is_subs);CHKERRQ(ierr);
1667   }
1668   if (sub_schurs->reuse_solver) {
1669     ierr = PCBDDCReuseSolversReset(sub_schurs->reuse_solver);CHKERRQ(ierr);
1670   }
1671   ierr = PetscFree(sub_schurs->reuse_solver);CHKERRQ(ierr);
1672   if (sub_schurs->change) {
1673     for (i=0;i<sub_schurs->n_subs;i++) {
1674       ierr = KSPDestroy(&sub_schurs->change[i]);CHKERRQ(ierr);
1675       ierr = ISDestroy(&sub_schurs->change_primal_sub[i]);CHKERRQ(ierr);
1676     }
1677   }
1678   ierr = PetscFree(sub_schurs->change);CHKERRQ(ierr);
1679   ierr = PetscFree(sub_schurs->change_primal_sub);CHKERRQ(ierr);
1680   sub_schurs->n_subs = 0;
1681   PetscFunctionReturn(0);
1682 }
1683 
1684 PetscErrorCode PCBDDCSubSchursDestroy(PCBDDCSubSchurs* sub_schurs)
1685 {
1686   PetscErrorCode ierr;
1687 
1688   PetscFunctionBegin;
1689   ierr = PCBDDCSubSchursReset(*sub_schurs);CHKERRQ(ierr);
1690   ierr = PetscFree(*sub_schurs);CHKERRQ(ierr);
1691   PetscFunctionReturn(0);
1692 }
1693 
1694 PETSC_STATIC_INLINE PetscErrorCode PCBDDCAdjGetNextLayer_Private(PetscInt* queue_tip,PetscInt n_prev,PetscBT touched,PetscInt* xadj,PetscInt* adjncy,PetscInt* n_added)
1695 {
1696   PetscInt       i,j,n;
1697   PetscErrorCode ierr;
1698 
1699   PetscFunctionBegin;
1700   n = 0;
1701   for (i=-n_prev;i<0;i++) {
1702     PetscInt start_dof = queue_tip[i];
1703     for (j=xadj[start_dof];j<xadj[start_dof+1];j++) {
1704       PetscInt dof = adjncy[j];
1705       if (!PetscBTLookup(touched,dof)) {
1706         ierr = PetscBTSet(touched,dof);CHKERRQ(ierr);
1707         queue_tip[n] = dof;
1708         n++;
1709       }
1710     }
1711   }
1712   *n_added = n;
1713   PetscFunctionReturn(0);
1714 }
1715