xref: /petsc/src/ksp/pc/impls/bddc/bddc.c (revision b0f5fe9377c0bb7ceae821c2544bbd08938c982b)
1 /* TODOLIST
2 
3    Solvers
4    - Add support for cholesky for coarse solver (similar to local solvers)
5    - Propagate ksp prefixes for solvers to mat objects?
6 
7    User interface
8    - ** DM attached to pc?
9 
10    Debugging output
11    - * Better management of verbosity levels of debugging output
12 
13    Extra
14    - *** Is it possible to work with PCBDDCGraph on boundary indices only (less memory consumed)?
15    - BDDC with MG framework?
16 
17    FETIDP
18    - Move FETIDP code to its own classes
19 
20    MATIS related operations contained in BDDC code
21    - Provide general case for subassembling
22 
23 */
24 
25 #include <../src/ksp/pc/impls/bddc/bddc.h> /*I "petscpc.h" I*/  /* includes for fortran wrappers */
26 #include <../src/ksp/pc/impls/bddc/bddcprivate.h>
27 #include <petscblaslapack.h>
28 
29 /* temporarily declare it */
30 PetscErrorCode PCApply_BDDC(PC,Vec,Vec);
31 
32 /* -------------------------------------------------------------------------- */
33 #undef __FUNCT__
34 #define __FUNCT__ "PCSetFromOptions_BDDC"
35 PetscErrorCode PCSetFromOptions_BDDC(PetscOptions *PetscOptionsObject,PC pc)
36 {
37   PC_BDDC        *pcbddc = (PC_BDDC*)pc->data;
38   PetscErrorCode ierr;
39 
40   PetscFunctionBegin;
41   ierr = PetscOptionsHead(PetscOptionsObject,"BDDC options");CHKERRQ(ierr);
42   /* Verbose debugging */
43   ierr = PetscOptionsInt("-pc_bddc_check_level","Verbose output for PCBDDC (intended for debug)","none",pcbddc->dbg_flag,&pcbddc->dbg_flag,NULL);CHKERRQ(ierr);
44   /* Primal space cumstomization */
45   ierr = PetscOptionsBool("-pc_bddc_use_local_mat_graph","Use or not adjacency graph of local mat for interface analysis","none",pcbddc->use_local_adj,&pcbddc->use_local_adj,NULL);CHKERRQ(ierr);
46   ierr = PetscOptionsBool("-pc_bddc_use_vertices","Use or not corner dofs in coarse space","none",pcbddc->use_vertices,&pcbddc->use_vertices,NULL);CHKERRQ(ierr);
47   ierr = PetscOptionsBool("-pc_bddc_use_edges","Use or not edge constraints in coarse space","none",pcbddc->use_edges,&pcbddc->use_edges,NULL);CHKERRQ(ierr);
48   ierr = PetscOptionsBool("-pc_bddc_use_faces","Use or not face constraints in coarse space","none",pcbddc->use_faces,&pcbddc->use_faces,NULL);CHKERRQ(ierr);
49   ierr = PetscOptionsBool("-pc_bddc_use_true_nnsp","Use near null space attached to the matrix without modifications","none",pcbddc->use_nnsp_true,&pcbddc->use_nnsp_true,NULL);CHKERRQ(ierr);
50   ierr = PetscOptionsBool("-pc_bddc_use_qr_single","Use QR factorization for single constraints on cc (QR is used when multiple constraints are present)","none",pcbddc->use_qr_single,&pcbddc->use_qr_single,NULL);CHKERRQ(ierr);
51   /* Change of basis */
52   ierr = PetscOptionsBool("-pc_bddc_use_change_of_basis","Use or not internal change of basis on local edge nodes","none",pcbddc->use_change_of_basis,&pcbddc->use_change_of_basis,NULL);CHKERRQ(ierr);
53   ierr = PetscOptionsBool("-pc_bddc_use_change_on_faces","Use or not internal change of basis on local face nodes","none",pcbddc->use_change_on_faces,&pcbddc->use_change_on_faces,NULL);CHKERRQ(ierr);
54   if (!pcbddc->use_change_of_basis) {
55     pcbddc->use_change_on_faces = PETSC_FALSE;
56   }
57   /* Switch between M_2 (default) and M_3 preconditioners (as defined by C. Dohrmann in the ref. article) */
58   ierr = PetscOptionsBool("-pc_bddc_switch_static","Switch on static condensation ops around the interface preconditioner","none",pcbddc->switch_static,&pcbddc->switch_static,NULL);CHKERRQ(ierr);
59   ierr = PetscOptionsInt("-pc_bddc_coarse_redistribute","Number of procs where to redistribute coarse problem","none",pcbddc->redistribute_coarse,&pcbddc->redistribute_coarse,NULL);CHKERRQ(ierr);
60   ierr = PetscOptionsInt("-pc_bddc_coarsening_ratio","Set coarsening ratio used in multilevel coarsening","none",pcbddc->coarsening_ratio,&pcbddc->coarsening_ratio,NULL);CHKERRQ(ierr);
61   ierr = PetscOptionsInt("-pc_bddc_levels","Set maximum number of levels for multilevel","none",pcbddc->max_levels,&pcbddc->max_levels,NULL);CHKERRQ(ierr);
62   ierr = PetscOptionsBool("-pc_bddc_use_coarse_estimates","Use estimated eigenvalues for coarse problem","none",pcbddc->use_coarse_estimates,&pcbddc->use_coarse_estimates,NULL);CHKERRQ(ierr);
63   ierr = PetscOptionsBool("-pc_bddc_use_deluxe_scaling","Use deluxe scaling for BDDC","none",pcbddc->use_deluxe_scaling,&pcbddc->use_deluxe_scaling,NULL);CHKERRQ(ierr);
64   ierr = PetscOptionsBool("-pc_bddc_schur_rebuild","Whether or not the interface graph for Schur principal minors has to be rebuilt (i.e. define the interface without any adjacency)","none",pcbddc->sub_schurs_rebuild,&pcbddc->sub_schurs_rebuild,NULL);CHKERRQ(ierr);
65   ierr = PetscOptionsInt("-pc_bddc_schur_layers","Number of dofs' layers for the computation of principal minors (i.e. -1 uses all dofs)","none",pcbddc->sub_schurs_layers,&pcbddc->sub_schurs_layers,NULL);CHKERRQ(ierr);
66   ierr = PetscOptionsBool("-pc_bddc_schur_use_useradj","Whether or not the CSR graph specified by the user should be used for computing successive layers (default is to use adj of local mat)","none",pcbddc->sub_schurs_use_useradj,&pcbddc->sub_schurs_use_useradj,NULL);CHKERRQ(ierr);
67   ierr = PetscOptionsBool("-pc_bddc_deluxe_faster","Faster application of deluxe scaling (requires extra work during setup)","none",pcbddc->faster_deluxe,&pcbddc->faster_deluxe,NULL);CHKERRQ(ierr);
68   ierr = PetscOptionsReal("-pc_bddc_adaptive_threshold","Threshold to be used for adaptive selection of constraints","none",pcbddc->adaptive_threshold,&pcbddc->adaptive_threshold,NULL);CHKERRQ(ierr);
69   ierr = PetscOptionsInt("-pc_bddc_adaptive_nmin","Minimum number of constraints per connected components","none",pcbddc->adaptive_nmin,&pcbddc->adaptive_nmin,NULL);CHKERRQ(ierr);
70   ierr = PetscOptionsInt("-pc_bddc_adaptive_nmax","Maximum number of constraints per connected components","none",pcbddc->adaptive_nmax,&pcbddc->adaptive_nmax,NULL);CHKERRQ(ierr);
71   ierr = PetscOptionsBool("-pc_bddc_symmetric","Symmetric computation of primal basis functions","none",pcbddc->symmetric_primal,&pcbddc->symmetric_primal,NULL);CHKERRQ(ierr);
72   ierr = PetscOptionsInt("-pc_bddc_coarse_adj","Number of processors where to map the coarse adjacency list","none",pcbddc->coarse_adj_red,&pcbddc->coarse_adj_red,NULL);CHKERRQ(ierr);
73   ierr = PetscOptionsBool("-pc_bddc_benign_trick","Apply the benign subspace trick to a class of saddle point problems","none",pcbddc->benign_saddle_point,&pcbddc->benign_saddle_point,NULL);CHKERRQ(ierr);
74   ierr = PetscOptionsTail();CHKERRQ(ierr);
75   PetscFunctionReturn(0);
76 }
77 /* -------------------------------------------------------------------------- */
78 #undef __FUNCT__
79 #define __FUNCT__ "PCBDDCSetChangeOfBasisMat_BDDC"
80 static PetscErrorCode PCBDDCSetChangeOfBasisMat_BDDC(PC pc, Mat change)
81 {
82   PC_BDDC        *pcbddc = (PC_BDDC*)pc->data;
83   PetscErrorCode ierr;
84 
85   PetscFunctionBegin;
86   ierr = MatDestroy(&pcbddc->user_ChangeOfBasisMatrix);CHKERRQ(ierr);
87   ierr = PetscObjectReference((PetscObject)change);CHKERRQ(ierr);
88   pcbddc->user_ChangeOfBasisMatrix = change;
89   PetscFunctionReturn(0);
90 }
91 #undef __FUNCT__
92 #define __FUNCT__ "PCBDDCSetChangeOfBasisMat"
93 /*@
94  PCBDDCSetChangeOfBasisMat - Set user defined change of basis for dofs
95 
96    Collective on PC
97 
98    Input Parameters:
99 +  pc - the preconditioning context
100 -  change - the change of basis matrix
101 
102    Level: intermediate
103 
104    Notes:
105 
106 .seealso: PCBDDC
107 @*/
108 PetscErrorCode PCBDDCSetChangeOfBasisMat(PC pc, Mat change)
109 {
110   PetscErrorCode ierr;
111 
112   PetscFunctionBegin;
113   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
114   PetscValidHeaderSpecific(change,MAT_CLASSID,2);
115   PetscCheckSameComm(pc,1,change,2);
116   if (pc->mat) {
117     PetscInt rows_c,cols_c,rows,cols;
118     ierr = MatGetSize(pc->mat,&rows,&cols);CHKERRQ(ierr);
119     ierr = MatGetSize(change,&rows_c,&cols_c);CHKERRQ(ierr);
120     if (rows_c != rows) {
121       SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Invalid number of rows for change of basis matrix! %d != %d",rows_c,rows);
122     }
123     if (cols_c != cols) {
124       SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Invalid number of columns for change of basis matrix! %d != %d",cols_c,cols);
125     }
126     ierr = MatGetLocalSize(pc->mat,&rows,&cols);CHKERRQ(ierr);
127     ierr = MatGetLocalSize(change,&rows_c,&cols_c);CHKERRQ(ierr);
128     if (rows_c != rows) {
129       SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Invalid number of local rows for change of basis matrix! %d != %d",rows_c,rows);
130     }
131     if (cols_c != cols) {
132       SETERRQ2(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Invalid number of local columns for change of basis matrix! %d != %d",cols_c,cols);
133     }
134   }
135   ierr = PetscTryMethod(pc,"PCBDDCSetChangeOfBasisMat_C",(PC,Mat),(pc,change));CHKERRQ(ierr);
136   PetscFunctionReturn(0);
137 }
138 /* -------------------------------------------------------------------------- */
139 #undef __FUNCT__
140 #define __FUNCT__ "PCBDDCSetPrimalVerticesLocalIS_BDDC"
141 static PetscErrorCode PCBDDCSetPrimalVerticesLocalIS_BDDC(PC pc, IS PrimalVertices)
142 {
143   PC_BDDC        *pcbddc = (PC_BDDC*)pc->data;
144   PetscErrorCode ierr;
145 
146   PetscFunctionBegin;
147   ierr = ISDestroy(&pcbddc->user_primal_vertices);CHKERRQ(ierr);
148   ierr = PetscObjectReference((PetscObject)PrimalVertices);CHKERRQ(ierr);
149   pcbddc->user_primal_vertices = PrimalVertices;
150   PetscFunctionReturn(0);
151 }
152 #undef __FUNCT__
153 #define __FUNCT__ "PCBDDCSetPrimalVerticesLocalIS"
154 /*@
155  PCBDDCSetPrimalVerticesLocalIS - Set additional user defined primal vertices in PCBDDC
156 
157    Collective
158 
159    Input Parameters:
160 +  pc - the preconditioning context
161 -  PrimalVertices - index set of primal vertices in local numbering (can be empty)
162 
163    Level: intermediate
164 
165    Notes:
166 
167 .seealso: PCBDDC
168 @*/
169 PetscErrorCode PCBDDCSetPrimalVerticesLocalIS(PC pc, IS PrimalVertices)
170 {
171   PetscErrorCode ierr;
172 
173   PetscFunctionBegin;
174   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
175   PetscValidHeaderSpecific(PrimalVertices,IS_CLASSID,2);
176   PetscCheckSameComm(pc,1,PrimalVertices,2);
177   ierr = PetscTryMethod(pc,"PCBDDCSetPrimalVerticesLocalIS_C",(PC,IS),(pc,PrimalVertices));CHKERRQ(ierr);
178   PetscFunctionReturn(0);
179 }
180 /* -------------------------------------------------------------------------- */
181 #undef __FUNCT__
182 #define __FUNCT__ "PCBDDCSetCoarseningRatio_BDDC"
183 static PetscErrorCode PCBDDCSetCoarseningRatio_BDDC(PC pc,PetscInt k)
184 {
185   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
186 
187   PetscFunctionBegin;
188   pcbddc->coarsening_ratio = k;
189   PetscFunctionReturn(0);
190 }
191 
192 #undef __FUNCT__
193 #define __FUNCT__ "PCBDDCSetCoarseningRatio"
194 /*@
195  PCBDDCSetCoarseningRatio - Set coarsening ratio used in multilevel
196 
197    Logically collective on PC
198 
199    Input Parameters:
200 +  pc - the preconditioning context
201 -  k - coarsening ratio (H/h at the coarser level)
202 
203    Options Database Keys:
204 .    -pc_bddc_coarsening_ratio
205 
206    Level: intermediate
207 
208    Notes:
209      Approximatively k subdomains at the finer level will be aggregated into a single subdomain at the coarser level
210 
211 .seealso: PCBDDC, PCBDDCSetLevels()
212 @*/
213 PetscErrorCode PCBDDCSetCoarseningRatio(PC pc,PetscInt k)
214 {
215   PetscErrorCode ierr;
216 
217   PetscFunctionBegin;
218   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
219   PetscValidLogicalCollectiveInt(pc,k,2);
220   ierr = PetscTryMethod(pc,"PCBDDCSetCoarseningRatio_C",(PC,PetscInt),(pc,k));CHKERRQ(ierr);
221   PetscFunctionReturn(0);
222 }
223 
224 /* The following functions (PCBDDCSetUseExactDirichlet PCBDDCSetLevel) are not public */
225 #undef __FUNCT__
226 #define __FUNCT__ "PCBDDCSetUseExactDirichlet_BDDC"
227 static PetscErrorCode PCBDDCSetUseExactDirichlet_BDDC(PC pc,PetscBool flg)
228 {
229   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
230 
231   PetscFunctionBegin;
232   pcbddc->use_exact_dirichlet_trick = flg;
233   PetscFunctionReturn(0);
234 }
235 
236 #undef __FUNCT__
237 #define __FUNCT__ "PCBDDCSetUseExactDirichlet"
238 PetscErrorCode PCBDDCSetUseExactDirichlet(PC pc,PetscBool flg)
239 {
240   PetscErrorCode ierr;
241 
242   PetscFunctionBegin;
243   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
244   PetscValidLogicalCollectiveBool(pc,flg,2);
245   ierr = PetscTryMethod(pc,"PCBDDCSetUseExactDirichlet_C",(PC,PetscBool),(pc,flg));CHKERRQ(ierr);
246   PetscFunctionReturn(0);
247 }
248 
249 #undef __FUNCT__
250 #define __FUNCT__ "PCBDDCSetLevel_BDDC"
251 static PetscErrorCode PCBDDCSetLevel_BDDC(PC pc,PetscInt level)
252 {
253   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
254 
255   PetscFunctionBegin;
256   pcbddc->current_level = level;
257   PetscFunctionReturn(0);
258 }
259 
260 #undef __FUNCT__
261 #define __FUNCT__ "PCBDDCSetLevel"
262 PetscErrorCode PCBDDCSetLevel(PC pc,PetscInt level)
263 {
264   PetscErrorCode ierr;
265 
266   PetscFunctionBegin;
267   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
268   PetscValidLogicalCollectiveInt(pc,level,2);
269   ierr = PetscTryMethod(pc,"PCBDDCSetLevel_C",(PC,PetscInt),(pc,level));CHKERRQ(ierr);
270   PetscFunctionReturn(0);
271 }
272 
273 #undef __FUNCT__
274 #define __FUNCT__ "PCBDDCSetLevels_BDDC"
275 static PetscErrorCode PCBDDCSetLevels_BDDC(PC pc,PetscInt levels)
276 {
277   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
278 
279   PetscFunctionBegin;
280   pcbddc->max_levels = levels;
281   PetscFunctionReturn(0);
282 }
283 
284 #undef __FUNCT__
285 #define __FUNCT__ "PCBDDCSetLevels"
286 /*@
287  PCBDDCSetLevels - Sets the maximum number of levels for multilevel
288 
289    Logically collective on PC
290 
291    Input Parameters:
292 +  pc - the preconditioning context
293 -  levels - the maximum number of levels (max 9)
294 
295    Options Database Keys:
296 .    -pc_bddc_levels
297 
298    Level: intermediate
299 
300    Notes:
301      Default value is 0, i.e. traditional one-level BDDC
302 
303 .seealso: PCBDDC, PCBDDCSetCoarseningRatio()
304 @*/
305 PetscErrorCode PCBDDCSetLevels(PC pc,PetscInt levels)
306 {
307   PetscErrorCode ierr;
308 
309   PetscFunctionBegin;
310   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
311   PetscValidLogicalCollectiveInt(pc,levels,2);
312   if (levels > 99) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Maximum number of levels for bddc is 99\n");
313   ierr = PetscTryMethod(pc,"PCBDDCSetLevels_C",(PC,PetscInt),(pc,levels));CHKERRQ(ierr);
314   PetscFunctionReturn(0);
315 }
316 /* -------------------------------------------------------------------------- */
317 
318 #undef __FUNCT__
319 #define __FUNCT__ "PCBDDCSetNullSpace_BDDC"
320 static PetscErrorCode PCBDDCSetNullSpace_BDDC(PC pc,MatNullSpace NullSpace)
321 {
322   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
323   PetscErrorCode ierr;
324 
325   PetscFunctionBegin;
326   ierr = PetscObjectReference((PetscObject)NullSpace);CHKERRQ(ierr);
327   ierr = MatNullSpaceDestroy(&pcbddc->NullSpace);CHKERRQ(ierr);
328   pcbddc->NullSpace = NullSpace;
329   PetscFunctionReturn(0);
330 }
331 
332 #undef __FUNCT__
333 #define __FUNCT__ "PCBDDCSetNullSpace"
334 /*@
335  PCBDDCSetNullSpace - Set nullspace for BDDC operator
336 
337    Logically collective on PC and MatNullSpace
338 
339    Input Parameters:
340 +  pc - the preconditioning context
341 -  NullSpace - Null space of the linear operator to be preconditioned (Pmat)
342 
343    Level: intermediate
344 
345    Notes:
346 
347 .seealso: PCBDDC
348 @*/
349 PetscErrorCode PCBDDCSetNullSpace(PC pc,MatNullSpace NullSpace)
350 {
351   PetscErrorCode ierr;
352 
353   PetscFunctionBegin;
354   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
355   PetscValidHeaderSpecific(NullSpace,MAT_NULLSPACE_CLASSID,2);
356   PetscCheckSameComm(pc,1,NullSpace,2);
357   ierr = PetscTryMethod(pc,"PCBDDCSetNullSpace_C",(PC,MatNullSpace),(pc,NullSpace));CHKERRQ(ierr);
358   PetscFunctionReturn(0);
359 }
360 /* -------------------------------------------------------------------------- */
361 
362 #undef __FUNCT__
363 #define __FUNCT__ "PCBDDCSetDirichletBoundaries_BDDC"
364 static PetscErrorCode PCBDDCSetDirichletBoundaries_BDDC(PC pc,IS DirichletBoundaries)
365 {
366   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
367   PetscErrorCode ierr;
368 
369   PetscFunctionBegin;
370   /* last user setting takes precendence -> destroy any other customization */
371   ierr = ISDestroy(&pcbddc->DirichletBoundariesLocal);CHKERRQ(ierr);
372   ierr = ISDestroy(&pcbddc->DirichletBoundaries);CHKERRQ(ierr);
373   ierr = PetscObjectReference((PetscObject)DirichletBoundaries);CHKERRQ(ierr);
374   pcbddc->DirichletBoundaries = DirichletBoundaries;
375   pcbddc->recompute_topography = PETSC_TRUE;
376   PetscFunctionReturn(0);
377 }
378 
379 #undef __FUNCT__
380 #define __FUNCT__ "PCBDDCSetDirichletBoundaries"
381 /*@
382  PCBDDCSetDirichletBoundaries - Set IS defining Dirichlet boundaries for the global problem.
383 
384    Collective
385 
386    Input Parameters:
387 +  pc - the preconditioning context
388 -  DirichletBoundaries - parallel IS defining the Dirichlet boundaries
389 
390    Level: intermediate
391 
392    Notes:
393      Provide the information if you used MatZeroRows/Columns routines. Any process can list any global node
394 
395 .seealso: PCBDDC, PCBDDCSetDirichletBoundariesLocal(), MatZeroRows(), MatZeroRowsColumns()
396 @*/
397 PetscErrorCode PCBDDCSetDirichletBoundaries(PC pc,IS DirichletBoundaries)
398 {
399   PetscErrorCode ierr;
400 
401   PetscFunctionBegin;
402   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
403   PetscValidHeaderSpecific(DirichletBoundaries,IS_CLASSID,2);
404   PetscCheckSameComm(pc,1,DirichletBoundaries,2);
405   ierr = PetscTryMethod(pc,"PCBDDCSetDirichletBoundaries_C",(PC,IS),(pc,DirichletBoundaries));CHKERRQ(ierr);
406   PetscFunctionReturn(0);
407 }
408 /* -------------------------------------------------------------------------- */
409 
410 #undef __FUNCT__
411 #define __FUNCT__ "PCBDDCSetDirichletBoundariesLocal_BDDC"
412 static PetscErrorCode PCBDDCSetDirichletBoundariesLocal_BDDC(PC pc,IS DirichletBoundaries)
413 {
414   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
415   PetscErrorCode ierr;
416 
417   PetscFunctionBegin;
418   /* last user setting takes precendence -> destroy any other customization */
419   ierr = ISDestroy(&pcbddc->DirichletBoundariesLocal);CHKERRQ(ierr);
420   ierr = ISDestroy(&pcbddc->DirichletBoundaries);CHKERRQ(ierr);
421   ierr = PetscObjectReference((PetscObject)DirichletBoundaries);CHKERRQ(ierr);
422   pcbddc->DirichletBoundariesLocal = DirichletBoundaries;
423   pcbddc->recompute_topography = PETSC_TRUE;
424   PetscFunctionReturn(0);
425 }
426 
427 #undef __FUNCT__
428 #define __FUNCT__ "PCBDDCSetDirichletBoundariesLocal"
429 /*@
430  PCBDDCSetDirichletBoundariesLocal - Set IS defining Dirichlet boundaries for the global problem in local ordering.
431 
432    Collective
433 
434    Input Parameters:
435 +  pc - the preconditioning context
436 -  DirichletBoundaries - parallel IS defining the Dirichlet boundaries (in local ordering)
437 
438    Level: intermediate
439 
440    Notes:
441 
442 .seealso: PCBDDC, PCBDDCSetDirichletBoundaries(), MatZeroRows(), MatZeroRowsColumns()
443 @*/
444 PetscErrorCode PCBDDCSetDirichletBoundariesLocal(PC pc,IS DirichletBoundaries)
445 {
446   PetscErrorCode ierr;
447 
448   PetscFunctionBegin;
449   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
450   PetscValidHeaderSpecific(DirichletBoundaries,IS_CLASSID,2);
451   PetscCheckSameComm(pc,1,DirichletBoundaries,2);
452   ierr = PetscTryMethod(pc,"PCBDDCSetDirichletBoundariesLocal_C",(PC,IS),(pc,DirichletBoundaries));CHKERRQ(ierr);
453   PetscFunctionReturn(0);
454 }
455 /* -------------------------------------------------------------------------- */
456 
457 #undef __FUNCT__
458 #define __FUNCT__ "PCBDDCSetNeumannBoundaries_BDDC"
459 static PetscErrorCode PCBDDCSetNeumannBoundaries_BDDC(PC pc,IS NeumannBoundaries)
460 {
461   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
462   PetscErrorCode ierr;
463 
464   PetscFunctionBegin;
465   /* last user setting takes precendence -> destroy any other customization */
466   ierr = ISDestroy(&pcbddc->NeumannBoundariesLocal);CHKERRQ(ierr);
467   ierr = ISDestroy(&pcbddc->NeumannBoundaries);CHKERRQ(ierr);
468   ierr = PetscObjectReference((PetscObject)NeumannBoundaries);CHKERRQ(ierr);
469   pcbddc->NeumannBoundaries = NeumannBoundaries;
470   pcbddc->recompute_topography = PETSC_TRUE;
471   PetscFunctionReturn(0);
472 }
473 
474 #undef __FUNCT__
475 #define __FUNCT__ "PCBDDCSetNeumannBoundaries"
476 /*@
477  PCBDDCSetNeumannBoundaries - Set IS defining Neumann boundaries for the global problem.
478 
479    Collective
480 
481    Input Parameters:
482 +  pc - the preconditioning context
483 -  NeumannBoundaries - parallel IS defining the Neumann boundaries
484 
485    Level: intermediate
486 
487    Notes:
488      Any process can list any global node
489 
490 .seealso: PCBDDC, PCBDDCSetNeumannBoundariesLocal()
491 @*/
492 PetscErrorCode PCBDDCSetNeumannBoundaries(PC pc,IS NeumannBoundaries)
493 {
494   PetscErrorCode ierr;
495 
496   PetscFunctionBegin;
497   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
498   PetscValidHeaderSpecific(NeumannBoundaries,IS_CLASSID,2);
499   PetscCheckSameComm(pc,1,NeumannBoundaries,2);
500   ierr = PetscTryMethod(pc,"PCBDDCSetNeumannBoundaries_C",(PC,IS),(pc,NeumannBoundaries));CHKERRQ(ierr);
501   PetscFunctionReturn(0);
502 }
503 /* -------------------------------------------------------------------------- */
504 
505 #undef __FUNCT__
506 #define __FUNCT__ "PCBDDCSetNeumannBoundariesLocal_BDDC"
507 static PetscErrorCode PCBDDCSetNeumannBoundariesLocal_BDDC(PC pc,IS NeumannBoundaries)
508 {
509   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
510   PetscErrorCode ierr;
511 
512   PetscFunctionBegin;
513   /* last user setting takes precendence -> destroy any other customization */
514   ierr = ISDestroy(&pcbddc->NeumannBoundariesLocal);CHKERRQ(ierr);
515   ierr = ISDestroy(&pcbddc->NeumannBoundaries);CHKERRQ(ierr);
516   ierr = PetscObjectReference((PetscObject)NeumannBoundaries);CHKERRQ(ierr);
517   pcbddc->NeumannBoundariesLocal = NeumannBoundaries;
518   pcbddc->recompute_topography = PETSC_TRUE;
519   PetscFunctionReturn(0);
520 }
521 
522 #undef __FUNCT__
523 #define __FUNCT__ "PCBDDCSetNeumannBoundariesLocal"
524 /*@
525  PCBDDCSetNeumannBoundariesLocal - Set IS defining Neumann boundaries for the global problem in local ordering.
526 
527    Collective
528 
529    Input Parameters:
530 +  pc - the preconditioning context
531 -  NeumannBoundaries - parallel IS defining the subdomain part of Neumann boundaries (in local ordering)
532 
533    Level: intermediate
534 
535    Notes:
536 
537 .seealso: PCBDDC, PCBDDCSetNeumannBoundaries()
538 @*/
539 PetscErrorCode PCBDDCSetNeumannBoundariesLocal(PC pc,IS NeumannBoundaries)
540 {
541   PetscErrorCode ierr;
542 
543   PetscFunctionBegin;
544   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
545   PetscValidHeaderSpecific(NeumannBoundaries,IS_CLASSID,2);
546   PetscCheckSameComm(pc,1,NeumannBoundaries,2);
547   ierr = PetscTryMethod(pc,"PCBDDCSetNeumannBoundariesLocal_C",(PC,IS),(pc,NeumannBoundaries));CHKERRQ(ierr);
548   PetscFunctionReturn(0);
549 }
550 /* -------------------------------------------------------------------------- */
551 
552 #undef __FUNCT__
553 #define __FUNCT__ "PCBDDCGetDirichletBoundaries_BDDC"
554 static PetscErrorCode PCBDDCGetDirichletBoundaries_BDDC(PC pc,IS *DirichletBoundaries)
555 {
556   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
557 
558   PetscFunctionBegin;
559   *DirichletBoundaries = pcbddc->DirichletBoundaries;
560   PetscFunctionReturn(0);
561 }
562 
563 #undef __FUNCT__
564 #define __FUNCT__ "PCBDDCGetDirichletBoundaries"
565 /*@
566  PCBDDCGetDirichletBoundaries - Get parallel IS for Dirichlet boundaries
567 
568    Collective
569 
570    Input Parameters:
571 .  pc - the preconditioning context
572 
573    Output Parameters:
574 .  DirichletBoundaries - index set defining the Dirichlet boundaries
575 
576    Level: intermediate
577 
578    Notes:
579      The IS returned (if any) is the same passed in earlier by the user with PCBDDCSetDirichletBoundaries
580 
581 .seealso: PCBDDC
582 @*/
583 PetscErrorCode PCBDDCGetDirichletBoundaries(PC pc,IS *DirichletBoundaries)
584 {
585   PetscErrorCode ierr;
586 
587   PetscFunctionBegin;
588   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
589   ierr = PetscUseMethod(pc,"PCBDDCGetDirichletBoundaries_C",(PC,IS*),(pc,DirichletBoundaries));CHKERRQ(ierr);
590   PetscFunctionReturn(0);
591 }
592 /* -------------------------------------------------------------------------- */
593 
594 #undef __FUNCT__
595 #define __FUNCT__ "PCBDDCGetDirichletBoundariesLocal_BDDC"
596 static PetscErrorCode PCBDDCGetDirichletBoundariesLocal_BDDC(PC pc,IS *DirichletBoundaries)
597 {
598   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
599 
600   PetscFunctionBegin;
601   *DirichletBoundaries = pcbddc->DirichletBoundariesLocal;
602   PetscFunctionReturn(0);
603 }
604 
605 #undef __FUNCT__
606 #define __FUNCT__ "PCBDDCGetDirichletBoundariesLocal"
607 /*@
608  PCBDDCGetDirichletBoundariesLocal - Get parallel IS for Dirichlet boundaries (in local ordering)
609 
610    Collective
611 
612    Input Parameters:
613 .  pc - the preconditioning context
614 
615    Output Parameters:
616 .  DirichletBoundaries - index set defining the subdomain part of Dirichlet boundaries
617 
618    Level: intermediate
619 
620    Notes:
621      The IS returned could be the same passed in earlier by the user (if provided with PCBDDCSetDirichletBoundariesLocal) or a global-to-local map of the global IS (if provided with PCBDDCSetDirichletBoundaries).
622           In the latter case, the IS will be available after PCSetUp.
623 
624 .seealso: PCBDDC
625 @*/
626 PetscErrorCode PCBDDCGetDirichletBoundariesLocal(PC pc,IS *DirichletBoundaries)
627 {
628   PetscErrorCode ierr;
629 
630   PetscFunctionBegin;
631   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
632   ierr = PetscUseMethod(pc,"PCBDDCGetDirichletBoundariesLocal_C",(PC,IS*),(pc,DirichletBoundaries));CHKERRQ(ierr);
633   PetscFunctionReturn(0);
634 }
635 /* -------------------------------------------------------------------------- */
636 
637 #undef __FUNCT__
638 #define __FUNCT__ "PCBDDCGetNeumannBoundaries_BDDC"
639 static PetscErrorCode PCBDDCGetNeumannBoundaries_BDDC(PC pc,IS *NeumannBoundaries)
640 {
641   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
642 
643   PetscFunctionBegin;
644   *NeumannBoundaries = pcbddc->NeumannBoundaries;
645   PetscFunctionReturn(0);
646 }
647 
648 #undef __FUNCT__
649 #define __FUNCT__ "PCBDDCGetNeumannBoundaries"
650 /*@
651  PCBDDCGetNeumannBoundaries - Get parallel IS for Neumann boundaries
652 
653    Collective
654 
655    Input Parameters:
656 .  pc - the preconditioning context
657 
658    Output Parameters:
659 .  NeumannBoundaries - index set defining the Neumann boundaries
660 
661    Level: intermediate
662 
663    Notes:
664      The IS returned (if any) is the same passed in earlier by the user with PCBDDCSetNeumannBoundaries
665 
666 .seealso: PCBDDC
667 @*/
668 PetscErrorCode PCBDDCGetNeumannBoundaries(PC pc,IS *NeumannBoundaries)
669 {
670   PetscErrorCode ierr;
671 
672   PetscFunctionBegin;
673   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
674   ierr = PetscUseMethod(pc,"PCBDDCGetNeumannBoundaries_C",(PC,IS*),(pc,NeumannBoundaries));CHKERRQ(ierr);
675   PetscFunctionReturn(0);
676 }
677 /* -------------------------------------------------------------------------- */
678 
679 #undef __FUNCT__
680 #define __FUNCT__ "PCBDDCGetNeumannBoundariesLocal_BDDC"
681 static PetscErrorCode PCBDDCGetNeumannBoundariesLocal_BDDC(PC pc,IS *NeumannBoundaries)
682 {
683   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
684 
685   PetscFunctionBegin;
686   *NeumannBoundaries = pcbddc->NeumannBoundariesLocal;
687   PetscFunctionReturn(0);
688 }
689 
690 #undef __FUNCT__
691 #define __FUNCT__ "PCBDDCGetNeumannBoundariesLocal"
692 /*@
693  PCBDDCGetNeumannBoundariesLocal - Get parallel IS for Neumann boundaries (in local ordering)
694 
695    Collective
696 
697    Input Parameters:
698 .  pc - the preconditioning context
699 
700    Output Parameters:
701 .  NeumannBoundaries - index set defining the subdomain part of Neumann boundaries
702 
703    Level: intermediate
704 
705    Notes:
706      The IS returned could be the same passed in earlier by the user (if provided with PCBDDCSetNeumannBoundariesLocal) or a global-to-local map of the global IS (if provided with PCBDDCSetNeumannBoundaries).
707           In the latter case, the IS will be available after PCSetUp.
708 
709 .seealso: PCBDDC
710 @*/
711 PetscErrorCode PCBDDCGetNeumannBoundariesLocal(PC pc,IS *NeumannBoundaries)
712 {
713   PetscErrorCode ierr;
714 
715   PetscFunctionBegin;
716   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
717   ierr = PetscUseMethod(pc,"PCBDDCGetNeumannBoundariesLocal_C",(PC,IS*),(pc,NeumannBoundaries));CHKERRQ(ierr);
718   PetscFunctionReturn(0);
719 }
720 /* -------------------------------------------------------------------------- */
721 
722 #undef __FUNCT__
723 #define __FUNCT__ "PCBDDCSetLocalAdjacencyGraph_BDDC"
724 static PetscErrorCode PCBDDCSetLocalAdjacencyGraph_BDDC(PC pc, PetscInt nvtxs,const PetscInt xadj[],const PetscInt adjncy[], PetscCopyMode copymode)
725 {
726   PC_BDDC        *pcbddc = (PC_BDDC*)pc->data;
727   PCBDDCGraph    mat_graph = pcbddc->mat_graph;
728   PetscErrorCode ierr;
729 
730   PetscFunctionBegin;
731   /* free old CSR */
732   ierr = PCBDDCGraphResetCSR(mat_graph);CHKERRQ(ierr);
733   /* TODO: PCBDDCGraphSetAdjacency */
734   /* get CSR into graph structure */
735   if (copymode == PETSC_COPY_VALUES) {
736     ierr = PetscMalloc1(nvtxs+1,&mat_graph->xadj);CHKERRQ(ierr);
737     ierr = PetscMalloc1(xadj[nvtxs],&mat_graph->adjncy);CHKERRQ(ierr);
738     ierr = PetscMemcpy(mat_graph->xadj,xadj,(nvtxs+1)*sizeof(PetscInt));CHKERRQ(ierr);
739     ierr = PetscMemcpy(mat_graph->adjncy,adjncy,xadj[nvtxs]*sizeof(PetscInt));CHKERRQ(ierr);
740   } else if (copymode == PETSC_OWN_POINTER) {
741     mat_graph->xadj = (PetscInt*)xadj;
742     mat_graph->adjncy = (PetscInt*)adjncy;
743   }
744   mat_graph->nvtxs_csr = nvtxs;
745   PetscFunctionReturn(0);
746 }
747 
748 #undef __FUNCT__
749 #define __FUNCT__ "PCBDDCSetLocalAdjacencyGraph"
750 /*@
751  PCBDDCSetLocalAdjacencyGraph - Set adjacency structure (CSR graph) of the local matrix
752 
753    Not collective
754 
755    Input Parameters:
756 +  pc - the preconditioning context
757 .  nvtxs - number of local vertices of the graph (i.e., the size of the local problem)
758 .  xadj, adjncy - the CSR graph
759 -  copymode - either PETSC_COPY_VALUES or PETSC_OWN_POINTER.
760 
761    Level: intermediate
762 
763    Notes:
764 
765 .seealso: PCBDDC,PetscCopyMode
766 @*/
767 PetscErrorCode PCBDDCSetLocalAdjacencyGraph(PC pc,PetscInt nvtxs,const PetscInt xadj[],const PetscInt adjncy[], PetscCopyMode copymode)
768 {
769   void (*f)(void) = 0;
770   PetscErrorCode ierr;
771 
772   PetscFunctionBegin;
773   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
774   PetscValidIntPointer(xadj,3);
775   PetscValidIntPointer(adjncy,4);
776   if (copymode != PETSC_COPY_VALUES && copymode != PETSC_OWN_POINTER) {
777     SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_SUP,"Unsupported copy mode %d in %s\n",copymode,__FUNCT__);
778   }
779   ierr = PetscTryMethod(pc,"PCBDDCSetLocalAdjacencyGraph_C",(PC,PetscInt,const PetscInt[],const PetscInt[],PetscCopyMode),(pc,nvtxs,xadj,adjncy,copymode));CHKERRQ(ierr);
780   /* free arrays if PCBDDC is not the PC type */
781   ierr = PetscObjectQueryFunction((PetscObject)pc,"PCBDDCSetLocalAdjacencyGraph_C",&f);CHKERRQ(ierr);
782   if (!f && copymode == PETSC_OWN_POINTER) {
783     ierr = PetscFree(xadj);CHKERRQ(ierr);
784     ierr = PetscFree(adjncy);CHKERRQ(ierr);
785   }
786   PetscFunctionReturn(0);
787 }
788 /* -------------------------------------------------------------------------- */
789 
790 #undef __FUNCT__
791 #define __FUNCT__ "PCBDDCSetDofsSplittingLocal_BDDC"
792 static PetscErrorCode PCBDDCSetDofsSplittingLocal_BDDC(PC pc,PetscInt n_is, IS ISForDofs[])
793 {
794   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
795   PetscInt i;
796   PetscErrorCode ierr;
797 
798   PetscFunctionBegin;
799   /* Destroy ISes if they were already set */
800   for (i=0;i<pcbddc->n_ISForDofsLocal;i++) {
801     ierr = ISDestroy(&pcbddc->ISForDofsLocal[i]);CHKERRQ(ierr);
802   }
803   ierr = PetscFree(pcbddc->ISForDofsLocal);CHKERRQ(ierr);
804   /* last user setting takes precendence -> destroy any other customization */
805   for (i=0;i<pcbddc->n_ISForDofs;i++) {
806     ierr = ISDestroy(&pcbddc->ISForDofs[i]);CHKERRQ(ierr);
807   }
808   ierr = PetscFree(pcbddc->ISForDofs);CHKERRQ(ierr);
809   pcbddc->n_ISForDofs = 0;
810   /* allocate space then set */
811   if (n_is) {
812     ierr = PetscMalloc1(n_is,&pcbddc->ISForDofsLocal);CHKERRQ(ierr);
813   }
814   for (i=0;i<n_is;i++) {
815     ierr = PetscObjectReference((PetscObject)ISForDofs[i]);CHKERRQ(ierr);
816     pcbddc->ISForDofsLocal[i]=ISForDofs[i];
817   }
818   pcbddc->n_ISForDofsLocal=n_is;
819   if (n_is) pcbddc->user_provided_isfordofs = PETSC_TRUE;
820   pcbddc->recompute_topography = PETSC_TRUE;
821   PetscFunctionReturn(0);
822 }
823 
824 #undef __FUNCT__
825 #define __FUNCT__ "PCBDDCSetDofsSplittingLocal"
826 /*@
827  PCBDDCSetDofsSplittingLocal - Set index sets defining fields of the local subdomain matrix
828 
829    Collective
830 
831    Input Parameters:
832 +  pc - the preconditioning context
833 .  n_is - number of index sets defining the fields
834 -  ISForDofs - array of IS describing the fields in local ordering
835 
836    Level: intermediate
837 
838    Notes:
839      n_is should be the same among processes. Not all nodes need to be listed: unlisted nodes will belong to the complement field.
840 
841 .seealso: PCBDDC
842 @*/
843 PetscErrorCode PCBDDCSetDofsSplittingLocal(PC pc,PetscInt n_is, IS ISForDofs[])
844 {
845   PetscInt       i;
846   PetscErrorCode ierr;
847 
848   PetscFunctionBegin;
849   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
850   PetscValidLogicalCollectiveInt(pc,n_is,2);
851   for (i=0;i<n_is;i++) {
852     PetscCheckSameComm(pc,1,ISForDofs[i],3);
853     PetscValidHeaderSpecific(ISForDofs[i],IS_CLASSID,3);
854   }
855   ierr = PetscTryMethod(pc,"PCBDDCSetDofsSplittingLocal_C",(PC,PetscInt,IS[]),(pc,n_is,ISForDofs));CHKERRQ(ierr);
856   PetscFunctionReturn(0);
857 }
858 /* -------------------------------------------------------------------------- */
859 
860 #undef __FUNCT__
861 #define __FUNCT__ "PCBDDCSetDofsSplitting_BDDC"
862 static PetscErrorCode PCBDDCSetDofsSplitting_BDDC(PC pc,PetscInt n_is, IS ISForDofs[])
863 {
864   PC_BDDC  *pcbddc = (PC_BDDC*)pc->data;
865   PetscInt i;
866   PetscErrorCode ierr;
867 
868   PetscFunctionBegin;
869   /* Destroy ISes if they were already set */
870   for (i=0;i<pcbddc->n_ISForDofs;i++) {
871     ierr = ISDestroy(&pcbddc->ISForDofs[i]);CHKERRQ(ierr);
872   }
873   ierr = PetscFree(pcbddc->ISForDofs);CHKERRQ(ierr);
874   /* last user setting takes precendence -> destroy any other customization */
875   for (i=0;i<pcbddc->n_ISForDofsLocal;i++) {
876     ierr = ISDestroy(&pcbddc->ISForDofsLocal[i]);CHKERRQ(ierr);
877   }
878   ierr = PetscFree(pcbddc->ISForDofsLocal);CHKERRQ(ierr);
879   pcbddc->n_ISForDofsLocal = 0;
880   /* allocate space then set */
881   if (n_is) {
882     ierr = PetscMalloc1(n_is,&pcbddc->ISForDofs);CHKERRQ(ierr);
883   }
884   for (i=0;i<n_is;i++) {
885     ierr = PetscObjectReference((PetscObject)ISForDofs[i]);CHKERRQ(ierr);
886     pcbddc->ISForDofs[i]=ISForDofs[i];
887   }
888   pcbddc->n_ISForDofs=n_is;
889   if (n_is) pcbddc->user_provided_isfordofs = PETSC_TRUE;
890   pcbddc->recompute_topography = PETSC_TRUE;
891   PetscFunctionReturn(0);
892 }
893 
894 #undef __FUNCT__
895 #define __FUNCT__ "PCBDDCSetDofsSplitting"
896 /*@
897  PCBDDCSetDofsSplitting - Set index sets defining fields of the global matrix
898 
899    Collective
900 
901    Input Parameters:
902 +  pc - the preconditioning context
903 .  n_is - number of index sets defining the fields
904 -  ISForDofs - array of IS describing the fields in global ordering
905 
906    Level: intermediate
907 
908    Notes:
909      Any process can list any global node. Not all nodes need to be listed: unlisted nodes will belong to the complement field.
910 
911 .seealso: PCBDDC
912 @*/
913 PetscErrorCode PCBDDCSetDofsSplitting(PC pc,PetscInt n_is, IS ISForDofs[])
914 {
915   PetscInt       i;
916   PetscErrorCode ierr;
917 
918   PetscFunctionBegin;
919   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
920   PetscValidLogicalCollectiveInt(pc,n_is,2);
921   for (i=0;i<n_is;i++) {
922     PetscCheckSameComm(pc,1,ISForDofs[i],3);
923     PetscValidHeaderSpecific(ISForDofs[i],IS_CLASSID,3);
924   }
925   ierr = PetscTryMethod(pc,"PCBDDCSetDofsSplitting_C",(PC,PetscInt,IS[]),(pc,n_is,ISForDofs));CHKERRQ(ierr);
926   PetscFunctionReturn(0);
927 }
928 
929 /* -------------------------------------------------------------------------- */
930 #undef __FUNCT__
931 #define __FUNCT__ "PCPreSolve_BDDC"
932 /* -------------------------------------------------------------------------- */
933 /*
934    PCPreSolve_BDDC - Changes the right hand side and (if necessary) the initial
935                      guess if a transformation of basis approach has been selected.
936 
937    Input Parameter:
938 +  pc - the preconditioner contex
939 
940    Application Interface Routine: PCPreSolve()
941 
942    Notes:
943      The interface routine PCPreSolve() is not usually called directly by
944    the user, but instead is called by KSPSolve().
945 */
946 static PetscErrorCode PCPreSolve_BDDC(PC pc, KSP ksp, Vec rhs, Vec x)
947 {
948   PetscErrorCode ierr;
949   PC_BDDC        *pcbddc = (PC_BDDC*)pc->data;
950   PC_IS          *pcis = (PC_IS*)(pc->data);
951   Vec            used_vec;
952   PetscBool      copy_rhs = PETSC_TRUE;
953 
954   PetscFunctionBegin;
955   /* if we are working with cg, one dirichlet solve can be avoided during Krylov iterations */
956   if (ksp) {
957     PetscBool iscg;
958     ierr = PetscObjectTypeCompare((PetscObject)ksp,KSPCG,&iscg);CHKERRQ(ierr);
959     if (!iscg) {
960       ierr = PCBDDCSetUseExactDirichlet(pc,PETSC_FALSE);CHKERRQ(ierr);
961     }
962   }
963   /* Creates parallel work vectors used in presolve */
964   if (!pcbddc->original_rhs) {
965     ierr = VecDuplicate(pcis->vec1_global,&pcbddc->original_rhs);CHKERRQ(ierr);
966   }
967   if (!pcbddc->temp_solution) {
968     ierr = VecDuplicate(pcis->vec1_global,&pcbddc->temp_solution);CHKERRQ(ierr);
969   }
970 
971   if (x) {
972     ierr = PetscObjectReference((PetscObject)x);CHKERRQ(ierr);
973     used_vec = x;
974   } else { /* it can only happen when calling PCBDDCMatFETIDPGetRHS */
975     ierr = PetscObjectReference((PetscObject)pcbddc->temp_solution);CHKERRQ(ierr);
976     used_vec = pcbddc->temp_solution;
977     ierr = VecSet(used_vec,0.0);CHKERRQ(ierr);
978   }
979 
980   /* hack into ksp data structure since PCPreSolve comes earlier than setting to zero the guess in src/ksp/ksp/interface/itfunc.c */
981   if (ksp) {
982     /* store the flag for the initial guess since it will be restored back during PCPostSolve_BDDC */
983     ierr = KSPGetInitialGuessNonzero(ksp,&pcbddc->ksp_guess_nonzero);CHKERRQ(ierr);
984     if (!pcbddc->ksp_guess_nonzero) {
985       ierr = VecSet(used_vec,0.0);CHKERRQ(ierr);
986     }
987   }
988 
989   pcbddc->rhs_change = PETSC_FALSE;
990   /* Take into account zeroed rows -> change rhs and store solution removed */
991   if (rhs) {
992     IS dirIS = NULL;
993 
994     /* DirichletBoundariesLocal may not be consistent among neighbours; gets a dirichlet dofs IS from graph (may be cached) */
995     ierr = PCBDDCGraphGetDirichletDofs(pcbddc->mat_graph,&dirIS);CHKERRQ(ierr);
996     if (dirIS) {
997       Mat_IS            *matis = (Mat_IS*)pc->pmat->data;
998       PetscInt          dirsize,i,*is_indices;
999       PetscScalar       *array_x;
1000       const PetscScalar *array_diagonal;
1001 
1002       ierr = MatGetDiagonal(pc->pmat,pcis->vec1_global);CHKERRQ(ierr);
1003       ierr = VecPointwiseDivide(pcis->vec1_global,rhs,pcis->vec1_global);CHKERRQ(ierr);
1004       ierr = VecScatterBegin(matis->rctx,pcis->vec1_global,pcis->vec2_N,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1005       ierr = VecScatterEnd(matis->rctx,pcis->vec1_global,pcis->vec2_N,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1006       ierr = VecScatterBegin(matis->rctx,used_vec,pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1007       ierr = VecScatterEnd(matis->rctx,used_vec,pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1008       ierr = ISGetLocalSize(dirIS,&dirsize);CHKERRQ(ierr);
1009       ierr = VecGetArray(pcis->vec1_N,&array_x);CHKERRQ(ierr);
1010       ierr = VecGetArrayRead(pcis->vec2_N,&array_diagonal);CHKERRQ(ierr);
1011       ierr = ISGetIndices(dirIS,(const PetscInt**)&is_indices);CHKERRQ(ierr);
1012       for (i=0; i<dirsize; i++) array_x[is_indices[i]] = array_diagonal[is_indices[i]];
1013       ierr = ISRestoreIndices(dirIS,(const PetscInt**)&is_indices);CHKERRQ(ierr);
1014       ierr = VecRestoreArrayRead(pcis->vec2_N,&array_diagonal);CHKERRQ(ierr);
1015       ierr = VecRestoreArray(pcis->vec1_N,&array_x);CHKERRQ(ierr);
1016       ierr = VecScatterBegin(matis->rctx,pcis->vec1_N,used_vec,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1017       ierr = VecScatterEnd(matis->rctx,pcis->vec1_N,used_vec,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1018       pcbddc->rhs_change = PETSC_TRUE;
1019       ierr = ISDestroy(&dirIS);CHKERRQ(ierr);
1020     }
1021   }
1022 
1023   /* remove the computed solution or the initial guess from the rhs */
1024   if (pcbddc->rhs_change || (ksp && pcbddc->ksp_guess_nonzero) ) {
1025     /* store the original rhs */
1026     if (copy_rhs) {
1027       ierr = VecCopy(rhs,pcbddc->original_rhs);CHKERRQ(ierr);
1028       copy_rhs = PETSC_FALSE;
1029     }
1030     pcbddc->rhs_change = PETSC_TRUE;
1031     ierr = VecScale(used_vec,-1.0);CHKERRQ(ierr);
1032     ierr = MatMultAdd(pc->mat,used_vec,rhs,rhs);CHKERRQ(ierr);
1033     ierr = VecScale(used_vec,-1.0);CHKERRQ(ierr);
1034     ierr = VecCopy(used_vec,pcbddc->temp_solution);CHKERRQ(ierr);
1035     if (ksp) {
1036       ierr = KSPSetInitialGuessNonzero(ksp,PETSC_FALSE);CHKERRQ(ierr);
1037     }
1038   }
1039   ierr = VecDestroy(&used_vec);CHKERRQ(ierr);
1040 
1041   /* When using the benign trick: (TODO: what about FETI-DP?)
1042      - change rhs on pressures (iteration matrix is surely of type MATIS)
1043      - compute initial vector in benign space
1044   */
1045   if (rhs && pcbddc->benign_saddle_point) {
1046     Mat_IS *matis = (Mat_IS*)(pc->mat->data);
1047 
1048     /* store the original rhs */
1049     if (copy_rhs) {
1050       ierr = VecCopy(rhs,pcbddc->original_rhs);CHKERRQ(ierr);
1051       copy_rhs = PETSC_FALSE;
1052     }
1053 
1054     /* now change (locally) the basis */
1055     ierr = VecScatterBegin(matis->rctx,rhs,pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1056     ierr = VecScatterEnd(matis->rctx,rhs,pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1057     if (pcbddc->benign_change) {
1058       ierr = MatMultTranspose(pcbddc->benign_change,pcis->vec1_N,pcis->vec2_N);CHKERRQ(ierr);
1059       ierr = VecScatterBegin(matis->rctx,pcis->vec2_N,rhs,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1060       ierr = VecScatterEnd(matis->rctx,pcis->vec2_N,rhs,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1061       /* change local iteration matrix */
1062       ierr = MatPtAP(matis->A,pcbddc->benign_change,MAT_REUSE_MATRIX,2.0,&pcbddc->local_mat);CHKERRQ(ierr);
1063       ierr = MatDestroy(&pcbddc->benign_original_mat);CHKERRQ(ierr);
1064       ierr = PetscObjectReference((PetscObject)matis->A);CHKERRQ(ierr);
1065       pcbddc->benign_original_mat = matis->A;
1066       ierr = MatDestroy(&matis->A);CHKERRQ(ierr);
1067       ierr = PetscObjectReference((PetscObject)pcbddc->local_mat);CHKERRQ(ierr);
1068       matis->A = pcbddc->local_mat;
1069       ierr = MatDestroy(&pcbddc->local_mat);CHKERRQ(ierr);
1070     } else {
1071       ierr = VecScatterBegin(matis->rctx,pcis->vec1_N,rhs,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1072       ierr = VecScatterEnd(matis->rctx,pcis->vec1_N,rhs,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1073     }
1074     pcbddc->rhs_change = PETSC_TRUE;
1075 
1076     /* compute u^*_h as in Xuemin Tu's thesis (see Section 4.8.1) */
1077     /* TODO: what about Stokes? */
1078     if (!pcbddc->benign_vec) {
1079       ierr = VecDuplicate(rhs,&pcbddc->benign_vec);CHKERRQ(ierr);
1080     }
1081     ierr = VecSet(pcis->vec1_global,0.);CHKERRQ(ierr);
1082     pcbddc->benign_p0 = 0.;
1083     if (pcbddc->benign_p0_lidx >= 0) {
1084       const PetscScalar *array;
1085 
1086       ierr = VecGetArrayRead(pcis->vec2_N,&array);CHKERRQ(ierr);
1087       pcbddc->benign_p0 = array[pcbddc->benign_p0_lidx];
1088       ierr = VecRestoreArrayRead(pcis->vec2_N,&array);CHKERRQ(ierr);
1089     }
1090     ierr = PCBDDCBenignGetOrSetP0(pc,pcis->vec1_global,PETSC_FALSE);CHKERRQ(ierr);
1091     ierr = PCApply_BDDC(pc,pcis->vec1_global,pcbddc->benign_vec);CHKERRQ(ierr);
1092     pcbddc->benign_p0 = 0.;
1093     ierr = PCBDDCBenignGetOrSetP0(pc,pcbddc->benign_vec,PETSC_FALSE);CHKERRQ(ierr);
1094   }
1095 
1096   /* change rhs and iteration matrix if using the change of basis */
1097   if (pcbddc->ChangeOfBasisMatrix) {
1098     PCBDDCChange_ctx change_ctx;
1099 
1100     /* get change ctx */
1101     ierr = MatShellGetContext(pcbddc->new_global_mat,&change_ctx);CHKERRQ(ierr);
1102 
1103     /* set current iteration matrix inside change context (change of basis has been already set into the ctx during PCSetUp) */
1104     ierr = MatDestroy(&change_ctx->original_mat);CHKERRQ(ierr);
1105     ierr = PetscObjectReference((PetscObject)pc->mat);CHKERRQ(ierr);
1106     change_ctx->original_mat = pc->mat;
1107 
1108     /* change iteration matrix */
1109     ierr = MatDestroy(&pc->mat);CHKERRQ(ierr);
1110     ierr = PetscObjectReference((PetscObject)pcbddc->new_global_mat);CHKERRQ(ierr);
1111     pc->mat = pcbddc->new_global_mat;
1112 
1113     /* store the original rhs */
1114     if (copy_rhs) {
1115       ierr = VecCopy(rhs,pcbddc->original_rhs);CHKERRQ(ierr);
1116       copy_rhs = PETSC_FALSE;
1117     }
1118 
1119     /* change rhs */
1120     ierr = MatMultTranspose(change_ctx->global_change,rhs,pcis->vec1_global);CHKERRQ(ierr);
1121     ierr = VecCopy(pcis->vec1_global,rhs);CHKERRQ(ierr);
1122     pcbddc->rhs_change = PETSC_TRUE;
1123   }
1124 
1125   /* remove non-benign solution from the rhs */
1126   if (pcbddc->benign_saddle_point) {
1127     /* store the original rhs */
1128     if (copy_rhs) {
1129       ierr = VecCopy(rhs,pcbddc->original_rhs);CHKERRQ(ierr);
1130       copy_rhs = PETSC_FALSE;
1131     }
1132     ierr = VecScale(pcbddc->benign_vec,-1.0);CHKERRQ(ierr);
1133     ierr = MatMultAdd(pc->mat,pcbddc->benign_vec,rhs,rhs);CHKERRQ(ierr);
1134     pcbddc->rhs_change = PETSC_TRUE;
1135   }
1136 
1137   /* set initial guess if using PCG */
1138   if (x && pcbddc->use_exact_dirichlet_trick) {
1139     ierr = VecSet(x,0.0);CHKERRQ(ierr);
1140     ierr = VecScatterBegin(pcis->global_to_D,rhs,pcis->vec1_D,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1141     ierr = VecScatterEnd(pcis->global_to_D,rhs,pcis->vec1_D,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1142     ierr = KSPSolve(pcbddc->ksp_D,pcis->vec1_D,pcis->vec2_D);CHKERRQ(ierr);
1143     ierr = VecScatterBegin(pcis->global_to_D,pcis->vec2_D,x,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1144     ierr = VecScatterEnd(pcis->global_to_D,pcis->vec2_D,x,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1145     if (ksp) {
1146       ierr = KSPSetInitialGuessNonzero(ksp,PETSC_TRUE);CHKERRQ(ierr);
1147     }
1148   }
1149   if (pcbddc->benign_null) {
1150     MatNullSpace null_space;
1151     Vec          nullv;
1152     PetscBool    isnull;
1153 
1154     pcbddc->benign_p0 = 1.;
1155     ierr = VecDuplicate(pcis->vec1_global,&nullv);CHKERRQ(ierr);
1156     ierr = VecSet(nullv,0.);CHKERRQ(ierr);
1157     ierr = PCBDDCBenignGetOrSetP0(pc,nullv,PETSC_FALSE);CHKERRQ(ierr);
1158     ierr = VecNormalize(nullv,NULL);CHKERRQ(ierr);
1159     ierr = MatNullSpaceCreate(PetscObjectComm((PetscObject)pc),PETSC_FALSE,1,&nullv,&null_space);CHKERRQ(ierr);
1160     ierr = MatNullSpaceTest(null_space,pc->mat,&isnull);CHKERRQ(ierr);
1161     ierr = MatSetNullSpace(pc->mat,null_space);CHKERRQ(ierr);
1162     ierr = MatNullSpaceDestroy(&null_space);CHKERRQ(ierr);
1163     ierr = VecDestroy(&nullv);CHKERRQ(ierr);
1164   }
1165 
1166 
1167   /* remove nullspace if present */
1168   if (ksp && x && pcbddc->NullSpace) {
1169     ierr = MatNullSpaceRemove(pcbddc->NullSpace,x);CHKERRQ(ierr);
1170     /* store the original rhs */
1171     if (copy_rhs) {
1172       ierr = VecCopy(rhs,pcbddc->original_rhs);CHKERRQ(ierr);
1173       copy_rhs = PETSC_FALSE;
1174     }
1175     pcbddc->rhs_change = PETSC_TRUE;
1176     ierr = MatNullSpaceRemove(pcbddc->NullSpace,rhs);CHKERRQ(ierr);
1177   }
1178   PetscFunctionReturn(0);
1179 }
1180 
1181 /* -------------------------------------------------------------------------- */
1182 #undef __FUNCT__
1183 #define __FUNCT__ "PCPostSolve_BDDC"
1184 /* -------------------------------------------------------------------------- */
1185 /*
1186    PCPostSolve_BDDC - Changes the computed solution if a transformation of basis
1187                      approach has been selected. Also, restores rhs to its original state.
1188 
1189    Input Parameter:
1190 +  pc - the preconditioner contex
1191 
1192    Application Interface Routine: PCPostSolve()
1193 
1194    Notes:
1195      The interface routine PCPostSolve() is not usually called directly by
1196      the user, but instead is called by KSPSolve().
1197 */
1198 static PetscErrorCode PCPostSolve_BDDC(PC pc, KSP ksp, Vec rhs, Vec x)
1199 {
1200   PetscErrorCode ierr;
1201   PC_BDDC        *pcbddc = (PC_BDDC*)pc->data;
1202 
1203   PetscFunctionBegin;
1204   if (pcbddc->ChangeOfBasisMatrix) {
1205     PCBDDCChange_ctx change_ctx;
1206 
1207     /* get change ctx */
1208     ierr = MatShellGetContext(pcbddc->new_global_mat,&change_ctx);CHKERRQ(ierr);
1209 
1210     /* restore iteration matrix */
1211     ierr = MatDestroy(&pc->mat);CHKERRQ(ierr);
1212     ierr = PetscObjectReference((PetscObject)change_ctx->original_mat);CHKERRQ(ierr);
1213     pc->mat = change_ctx->original_mat;
1214 
1215     /* need to restore the local matrices */
1216     if (pcbddc->benign_saddle_point && pcbddc->benign_change) {
1217       Mat_IS *matis = (Mat_IS*)pc->mat->data;
1218 
1219       ierr = MatDestroy(&matis->A);CHKERRQ(ierr);
1220       ierr = PetscObjectReference((PetscObject)pcbddc->benign_original_mat);CHKERRQ(ierr);
1221       matis->A = pcbddc->benign_original_mat;
1222       ierr = MatDestroy(&pcbddc->benign_original_mat);CHKERRQ(ierr);
1223     }
1224 
1225     /* get solution in original basis */
1226     if (x) {
1227       PC_IS *pcis = (PC_IS*)(pc->data);
1228 
1229       /* restore solution on pressures */
1230       if (pcbddc->benign_saddle_point) {
1231         Mat_IS *matis = (Mat_IS*)pc->mat->data;
1232 
1233         /* add non-benign solution */
1234         ierr = VecAXPY(x,-1.0,pcbddc->benign_vec);CHKERRQ(ierr);
1235 
1236         /* change basis on pressures for x */
1237         ierr = VecScatterBegin(matis->rctx,x,pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1238         ierr = VecScatterEnd(matis->rctx,x,pcis->vec1_N,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1239         if (pcbddc->benign_change) {
1240 
1241           ierr = MatMult(pcbddc->benign_change,pcis->vec1_N,pcis->vec2_N);CHKERRQ(ierr);
1242           ierr = VecScatterBegin(matis->rctx,pcis->vec2_N,x,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1243           ierr = VecScatterEnd(matis->rctx,pcis->vec2_N,x,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1244         } else {
1245           ierr = VecScatterBegin(matis->rctx,pcis->vec1_N,x,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1246           ierr = VecScatterEnd(matis->rctx,pcis->vec1_N,x,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1247         }
1248       }
1249       /* change basis on x */
1250       ierr = MatMult(change_ctx->global_change,x,pcis->vec1_global);CHKERRQ(ierr);
1251       ierr = VecCopy(pcis->vec1_global,x);CHKERRQ(ierr);
1252     }
1253   }
1254 
1255   /* add solution removed in presolve */
1256   if (x && pcbddc->rhs_change) {
1257     ierr = VecAXPY(x,1.0,pcbddc->temp_solution);CHKERRQ(ierr);
1258   }
1259 
1260   /* restore rhs to its original state */
1261   if (rhs && pcbddc->rhs_change) {
1262     ierr = VecCopy(pcbddc->original_rhs,rhs);CHKERRQ(ierr);
1263   }
1264   pcbddc->rhs_change = PETSC_FALSE;
1265 
1266   /* restore ksp guess state */
1267   if (ksp) {
1268     ierr = KSPSetInitialGuessNonzero(ksp,pcbddc->ksp_guess_nonzero);CHKERRQ(ierr);
1269   }
1270   PetscFunctionReturn(0);
1271 }
1272 /* -------------------------------------------------------------------------- */
1273 #undef __FUNCT__
1274 #define __FUNCT__ "PCSetUp_BDDC"
1275 /* -------------------------------------------------------------------------- */
1276 /*
1277    PCSetUp_BDDC - Prepares for the use of the BDDC preconditioner
1278                   by setting data structures and options.
1279 
1280    Input Parameter:
1281 +  pc - the preconditioner context
1282 
1283    Application Interface Routine: PCSetUp()
1284 
1285    Notes:
1286      The interface routine PCSetUp() is not usually called directly by
1287      the user, but instead is called by PCApply() if necessary.
1288 */
1289 PetscErrorCode PCSetUp_BDDC(PC pc)
1290 {
1291   PetscErrorCode ierr;
1292   PC_BDDC*       pcbddc = (PC_BDDC*)pc->data;
1293   Mat_IS*        matis;
1294   MatNullSpace   nearnullspace;
1295   IS             zerodiag = NULL;
1296   PetscInt       nrows,ncols;
1297   PetscBool      computetopography,computesolvers,computesubschurs;
1298   PetscBool      computeconstraintsmatrix;
1299   PetscBool      new_nearnullspace_provided,ismatis;
1300 
1301   PetscFunctionBegin;
1302   ierr = PetscObjectTypeCompare((PetscObject)pc->pmat,MATIS,&ismatis);CHKERRQ(ierr);
1303   if (!ismatis) {
1304     SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONG,"PCBDDC preconditioner requires matrix of type MATIS");
1305   }
1306   ierr = MatGetSize(pc->pmat,&nrows,&ncols);CHKERRQ(ierr);
1307   if (nrows != ncols) {
1308     SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"PCBDDC preconditioner requires a square preconditioning matrix");
1309   }
1310   matis = (Mat_IS*)pc->pmat->data;
1311   /* the following lines of code should be replaced by a better logic between PCIS, PCNN, PCBDDC and other future nonoverlapping preconditioners */
1312   /* For BDDC we need to define a local "Neumann" problem different to that defined in PCISSetup
1313      Also, BDDC directly build the Dirichlet problem */
1314   /* split work */
1315   if (pc->setupcalled) {
1316     if (pc->flag == SAME_NONZERO_PATTERN) {
1317       computetopography = PETSC_FALSE;
1318       computesolvers = PETSC_TRUE;
1319     } else { /* DIFFERENT_NONZERO_PATTERN */
1320       computetopography = PETSC_TRUE;
1321       computesolvers = PETSC_TRUE;
1322     }
1323   } else {
1324     computetopography = PETSC_TRUE;
1325     computesolvers = PETSC_TRUE;
1326   }
1327   if (pcbddc->recompute_topography) {
1328     computetopography = PETSC_TRUE;
1329   }
1330   computeconstraintsmatrix = PETSC_FALSE;
1331 
1332   /* check parameters' compatibility */
1333   if (pcbddc->adaptive_threshold > 0.0 && !pcbddc->use_deluxe_scaling) {
1334     SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cannot compute adaptive constraints without deluxe scaling. Rerun with -pc_bddc_use_deluxe_scaling");
1335   }
1336   pcbddc->adaptive_selection = (PetscBool)(pcbddc->adaptive_threshold > 0.0 && pcbddc->use_deluxe_scaling);
1337   if (pcbddc->adaptive_selection) pcbddc->use_faces = PETSC_TRUE;
1338 
1339   computesubschurs = (PetscBool)(pcbddc->adaptive_selection || pcbddc->use_deluxe_scaling);
1340   if (pcbddc->faster_deluxe && pcbddc->adaptive_selection && pcbddc->use_change_of_basis) {
1341     SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_SUP,"Cannot compute faster deluxe if adaptivity and change of basis are both requested. Rerun with -pc_bddc_deluxe_faster false");
1342   }
1343 
1344   /* check if the iteration matrix is of type MATIS in case the benign trick has been requested */
1345   ierr = PetscObjectTypeCompare((PetscObject)pc->mat,MATIS,&ismatis);CHKERRQ(ierr);
1346   if (pcbddc->benign_saddle_point && !ismatis) {
1347     SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_WRONG,"PCBDDC preconditioner with benign subspace trick requires the iteration matrix to be of type MATIS");
1348   }
1349 
1350   /* Get stdout for dbg */
1351   if (pcbddc->dbg_flag) {
1352     if (!pcbddc->dbg_viewer) {
1353       pcbddc->dbg_viewer = PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)pc));
1354       ierr = PetscViewerASCIISynchronizedAllow(pcbddc->dbg_viewer,PETSC_TRUE);CHKERRQ(ierr);
1355     }
1356     ierr = PetscViewerASCIIAddTab(pcbddc->dbg_viewer,2*pcbddc->current_level);CHKERRQ(ierr);
1357   }
1358 
1359   if (pcbddc->user_ChangeOfBasisMatrix) {
1360     /* use_change_of_basis flag is used to automatically compute a change of basis from constraints */
1361     pcbddc->use_change_of_basis = PETSC_FALSE;
1362     ierr = PCBDDCComputeLocalMatrix(pc,pcbddc->user_ChangeOfBasisMatrix);CHKERRQ(ierr);
1363   } else {
1364     ierr = MatDestroy(&pcbddc->local_mat);CHKERRQ(ierr);
1365     ierr = PetscObjectReference((PetscObject)matis->A);CHKERRQ(ierr);
1366     pcbddc->local_mat = matis->A;
1367   }
1368 
1369   /* change basis on local pressures (aka zerodiag dofs) */
1370   if (pcbddc->benign_saddle_point) {
1371     /* detect local saddle point and change the basis in pcbddc->local_mat */
1372     ierr = PCBDDCBenignDetectSaddlePoint(pc,&zerodiag);CHKERRQ(ierr);
1373     /* pop B0 mat from pcbddc->local_mat */
1374     ierr = PCBDDCBenignPopOrPushB0(pc,PETSC_TRUE);CHKERRQ(ierr);
1375   }
1376 
1377   /* propagate relevant information */
1378   /* workaround for reals */
1379 #if !defined(PETSC_USE_COMPLEX)
1380   if (matis->A->symmetric_set) {
1381     ierr = MatSetOption(pcbddc->local_mat,MAT_HERMITIAN,matis->A->symmetric);CHKERRQ(ierr);
1382   }
1383 #endif
1384   if (matis->A->symmetric_set) {
1385     ierr = MatSetOption(pcbddc->local_mat,MAT_SYMMETRIC,matis->A->symmetric);CHKERRQ(ierr);
1386   }
1387   if (matis->A->spd_set) {
1388     ierr = MatSetOption(pcbddc->local_mat,MAT_SPD,matis->A->spd);CHKERRQ(ierr);
1389   }
1390 
1391   /* Set up all the "iterative substructuring" common block without computing solvers */
1392   {
1393     Mat temp_mat;
1394 
1395     temp_mat = matis->A;
1396     matis->A = pcbddc->local_mat;
1397     ierr = PCISSetUp(pc,PETSC_FALSE);CHKERRQ(ierr);
1398     pcbddc->local_mat = matis->A;
1399     matis->A = temp_mat;
1400   }
1401 
1402   /* Analyze interface */
1403   if (computetopography) {
1404     ierr = PCBDDCAnalyzeInterface(pc);CHKERRQ(ierr);
1405     computeconstraintsmatrix = PETSC_TRUE;
1406   }
1407 
1408   /* check existence of a divergence free extension, i.e.
1409      b(v_I,p_0) = 0 for all v_I (raise error if not).
1410      Also, check that PCBDDCBenignGetOrSetP0 works */
1411 #if defined(PETSC_USE_DEBUG)
1412   if (pcbddc->benign_saddle_point) {
1413     ierr = PCBDDCBenignCheck(pc,zerodiag);CHKERRQ(ierr);
1414   }
1415 #endif
1416 
1417   /* Setup local dirichlet solver ksp_D and sub_schurs solvers */
1418   if (computesolvers) {
1419     PCBDDCSubSchurs sub_schurs=pcbddc->sub_schurs;
1420 
1421     if (computesubschurs && computetopography) {
1422       ierr = PCBDDCInitSubSchurs(pc);CHKERRQ(ierr);
1423     }
1424     if (sub_schurs->use_mumps) {
1425       if (computesubschurs) {
1426         ierr = PCBDDCSetUpSubSchurs(pc);CHKERRQ(ierr);
1427       }
1428       ierr = PCBDDCSetUpLocalSolvers(pc,PETSC_TRUE,PETSC_FALSE);CHKERRQ(ierr);
1429     } else {
1430       ierr = PCBDDCSetUpLocalSolvers(pc,PETSC_TRUE,PETSC_FALSE);CHKERRQ(ierr);
1431       if (computesubschurs) {
1432         ierr = PCBDDCSetUpSubSchurs(pc);CHKERRQ(ierr);
1433       }
1434     }
1435     if (pcbddc->adaptive_selection) {
1436       ierr = PCBDDCAdaptiveSelection(pc);CHKERRQ(ierr);
1437       computeconstraintsmatrix = PETSC_TRUE;
1438     }
1439   }
1440 
1441   /* infer if NullSpace object attached to Mat via MatSetNearNullSpace has changed */
1442   new_nearnullspace_provided = PETSC_FALSE;
1443   ierr = MatGetNearNullSpace(pc->pmat,&nearnullspace);CHKERRQ(ierr);
1444   if (pcbddc->onearnullspace) { /* already used nearnullspace */
1445     if (!nearnullspace) { /* near null space attached to mat has been destroyed */
1446       new_nearnullspace_provided = PETSC_TRUE;
1447     } else {
1448       /* determine if the two nullspaces are different (should be lightweight) */
1449       if (nearnullspace != pcbddc->onearnullspace) {
1450         new_nearnullspace_provided = PETSC_TRUE;
1451       } else { /* maybe the user has changed the content of the nearnullspace so check vectors ObjectStateId */
1452         PetscInt         i;
1453         const Vec        *nearnullvecs;
1454         PetscObjectState state;
1455         PetscInt         nnsp_size;
1456         ierr = MatNullSpaceGetVecs(nearnullspace,NULL,&nnsp_size,&nearnullvecs);CHKERRQ(ierr);
1457         for (i=0;i<nnsp_size;i++) {
1458           ierr = PetscObjectStateGet((PetscObject)nearnullvecs[i],&state);CHKERRQ(ierr);
1459           if (pcbddc->onearnullvecs_state[i] != state) {
1460             new_nearnullspace_provided = PETSC_TRUE;
1461             break;
1462           }
1463         }
1464       }
1465     }
1466   } else {
1467     if (!nearnullspace) { /* both nearnullspaces are null */
1468       new_nearnullspace_provided = PETSC_FALSE;
1469     } else { /* nearnullspace attached later */
1470       new_nearnullspace_provided = PETSC_TRUE;
1471     }
1472   }
1473 
1474   /* Setup constraints and related work vectors */
1475   /* reset primal space flags */
1476   pcbddc->new_primal_space = PETSC_FALSE;
1477   pcbddc->new_primal_space_local = PETSC_FALSE;
1478   if (computeconstraintsmatrix || new_nearnullspace_provided) {
1479     /* It also sets the primal space flags */
1480     ierr = PCBDDCConstraintsSetUp(pc);CHKERRQ(ierr);
1481     /* Allocate needed local vectors (which depends on quantities defined during ConstraintsSetUp) */
1482     ierr = PCBDDCSetUpLocalWorkVectors(pc);CHKERRQ(ierr);
1483   }
1484 
1485   if (computesolvers || pcbddc->new_primal_space) {
1486     if (pcbddc->use_change_of_basis) {
1487       PC_IS *pcis = (PC_IS*)(pc->data);
1488       Mat   temp_mat = NULL;
1489 
1490       if (zerodiag) {
1491         /* insert B0 in pcbddc->local_mat */
1492         ierr = PCBDDCBenignPopOrPushB0(pc,PETSC_FALSE);CHKERRQ(ierr);
1493         /* swap local matrices */
1494         ierr = MatISGetLocalMat(pc->pmat,&temp_mat);CHKERRQ(ierr);
1495         ierr = PetscObjectReference((PetscObject)temp_mat);CHKERRQ(ierr);
1496         ierr = MatISSetLocalMat(pc->pmat,pcbddc->local_mat);CHKERRQ(ierr);
1497         ierr = MatDestroy(&pcbddc->local_mat);CHKERRQ(ierr);
1498       }
1499       ierr = PCBDDCComputeLocalMatrix(pc,pcbddc->ChangeOfBasisMatrix);CHKERRQ(ierr);
1500       if (zerodiag) {
1501         /* restore original matrix */
1502         ierr = MatISSetLocalMat(pc->pmat,temp_mat);CHKERRQ(ierr);
1503         ierr = PetscObjectDereference((PetscObject)temp_mat);CHKERRQ(ierr);
1504         /* pop B0 from pcbddc->local_mat */
1505         ierr = PCBDDCBenignPopOrPushB0(pc,PETSC_TRUE);CHKERRQ(ierr);
1506       }
1507       /* get submatrices */
1508       ierr = MatDestroy(&pcis->A_IB);CHKERRQ(ierr);
1509       ierr = MatDestroy(&pcis->A_BI);CHKERRQ(ierr);
1510       ierr = MatDestroy(&pcis->A_BB);CHKERRQ(ierr);
1511       ierr = MatGetSubMatrix(pcbddc->local_mat,pcis->is_B_local,pcis->is_B_local,MAT_INITIAL_MATRIX,&pcis->A_BB);CHKERRQ(ierr);
1512       ierr = MatGetSubMatrix(pcbddc->local_mat,pcis->is_I_local,pcis->is_B_local,MAT_INITIAL_MATRIX,&pcis->A_IB);CHKERRQ(ierr);
1513       ierr = MatGetSubMatrix(pcbddc->local_mat,pcis->is_B_local,pcis->is_I_local,MAT_INITIAL_MATRIX,&pcis->A_BI);CHKERRQ(ierr);
1514       /* set flag in pcis to not reuse submatrices during PCISCreate */
1515       pcis->reusesubmatrices = PETSC_FALSE;
1516     } else if (!pcbddc->user_ChangeOfBasisMatrix) {
1517       ierr = MatDestroy(&pcbddc->local_mat);CHKERRQ(ierr);
1518       ierr = PetscObjectReference((PetscObject)matis->A);CHKERRQ(ierr);
1519       pcbddc->local_mat = matis->A;
1520     }
1521     /* SetUp coarse and local Neumann solvers */
1522     ierr = PCBDDCSetUpSolvers(pc);CHKERRQ(ierr);
1523     /* SetUp Scaling operator */
1524     ierr = PCBDDCScalingSetUp(pc);CHKERRQ(ierr);
1525   }
1526   ierr = ISDestroy(&zerodiag);CHKERRQ(ierr);
1527 
1528   if (pcbddc->dbg_flag) {
1529     ierr = PetscViewerASCIISubtractTab(pcbddc->dbg_viewer,2*pcbddc->current_level);CHKERRQ(ierr);
1530   }
1531   PetscFunctionReturn(0);
1532 }
1533 
1534 /* -------------------------------------------------------------------------- */
1535 /*
1536    PCApply_BDDC - Applies the BDDC operator to a vector.
1537 
1538    Input Parameters:
1539 +  pc - the preconditioner context
1540 -  r - input vector (global)
1541 
1542    Output Parameter:
1543 .  z - output vector (global)
1544 
1545    Application Interface Routine: PCApply()
1546  */
1547 #undef __FUNCT__
1548 #define __FUNCT__ "PCApply_BDDC"
1549 PetscErrorCode PCApply_BDDC(PC pc,Vec r,Vec z)
1550 {
1551   PC_IS             *pcis = (PC_IS*)(pc->data);
1552   PC_BDDC           *pcbddc = (PC_BDDC*)(pc->data);
1553   PetscInt          n_B = pcis->n_B, n_D = pcis->n - n_B;
1554   PetscErrorCode    ierr;
1555   const PetscScalar one = 1.0;
1556   const PetscScalar m_one = -1.0;
1557   const PetscScalar zero = 0.0;
1558 
1559 /* This code is similar to that provided in nn.c for PCNN
1560    NN interface preconditioner changed to BDDC
1561    Added support for M_3 preconditioner in the reference article (code is active if pcbddc->switch_static == PETSC_TRUE) */
1562 
1563   PetscFunctionBegin;
1564   if (pcbddc->benign_saddle_point) { /* get p0 from r */
1565     ierr = PCBDDCBenignGetOrSetP0(pc,r,PETSC_TRUE);CHKERRQ(ierr);
1566   }
1567   if (!pcbddc->use_exact_dirichlet_trick) {
1568     ierr = VecCopy(r,z);CHKERRQ(ierr);
1569     /* First Dirichlet solve */
1570     ierr = VecScatterBegin(pcis->global_to_D,r,pcis->vec1_D,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1571     ierr = VecScatterEnd(pcis->global_to_D,r,pcis->vec1_D,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1572     /*
1573       Assembling right hand side for BDDC operator
1574       - pcis->vec1_D for the Dirichlet part (if needed, i.e. pcbddc->switch_static == PETSC_TRUE)
1575       - pcis->vec1_B the interface part of the global vector z
1576     */
1577     if (n_D) {
1578       ierr = KSPSolve(pcbddc->ksp_D,pcis->vec1_D,pcis->vec2_D);CHKERRQ(ierr);
1579       ierr = VecScale(pcis->vec2_D,m_one);CHKERRQ(ierr);
1580       if (pcbddc->switch_static) { ierr = MatMultAdd(pcis->A_II,pcis->vec2_D,pcis->vec1_D,pcis->vec1_D);CHKERRQ(ierr); }
1581       ierr = MatMult(pcis->A_BI,pcis->vec2_D,pcis->vec1_B);CHKERRQ(ierr);
1582     } else {
1583       ierr = VecSet(pcis->vec1_B,zero);CHKERRQ(ierr);
1584     }
1585     ierr = VecScatterBegin(pcis->global_to_B,pcis->vec1_B,z,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1586     ierr = VecScatterEnd(pcis->global_to_B,pcis->vec1_B,z,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1587     ierr = PCBDDCScalingRestriction(pc,z,pcis->vec1_B);CHKERRQ(ierr);
1588   } else {
1589     if (pcbddc->switch_static) {
1590       ierr = VecSet(pcis->vec1_D,zero);CHKERRQ(ierr);
1591     }
1592     ierr = PCBDDCScalingRestriction(pc,r,pcis->vec1_B);CHKERRQ(ierr);
1593   }
1594 
1595   /* Apply interface preconditioner
1596      input/output vecs: pcis->vec1_B and pcis->vec1_D */
1597   ierr = PCBDDCApplyInterfacePreconditioner(pc,PETSC_FALSE);CHKERRQ(ierr);
1598 
1599   /* Apply transpose of partition of unity operator */
1600   ierr = PCBDDCScalingExtension(pc,pcis->vec1_B,z);CHKERRQ(ierr);
1601 
1602   /* Second Dirichlet solve and assembling of output */
1603   ierr = VecScatterBegin(pcis->global_to_B,z,pcis->vec1_B,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1604   ierr = VecScatterEnd(pcis->global_to_B,z,pcis->vec1_B,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1605   if (n_B) {
1606     ierr = MatMult(pcis->A_IB,pcis->vec1_B,pcis->vec3_D);CHKERRQ(ierr);
1607     if (pcbddc->switch_static) { ierr = MatMultAdd(pcis->A_II,pcis->vec1_D,pcis->vec3_D,pcis->vec3_D);CHKERRQ(ierr); }
1608   } else if (pcbddc->switch_static) {
1609     ierr = MatMult(pcis->A_II,pcis->vec1_D,pcis->vec3_D);CHKERRQ(ierr);
1610   }
1611   ierr = KSPSolve(pcbddc->ksp_D,pcis->vec3_D,pcis->vec4_D);CHKERRQ(ierr);
1612 
1613   if (!pcbddc->use_exact_dirichlet_trick) {
1614     if (pcbddc->switch_static) {
1615       ierr = VecAXPBYPCZ(pcis->vec2_D,m_one,one,m_one,pcis->vec4_D,pcis->vec1_D);CHKERRQ(ierr);
1616     } else {
1617       ierr = VecAXPBY(pcis->vec2_D,m_one,m_one,pcis->vec4_D);CHKERRQ(ierr);
1618     }
1619     ierr = VecScatterBegin(pcis->global_to_D,pcis->vec2_D,z,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1620     ierr = VecScatterEnd(pcis->global_to_D,pcis->vec2_D,z,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1621   } else {
1622     if (pcbddc->switch_static) {
1623       ierr = VecAXPBY(pcis->vec4_D,one,m_one,pcis->vec1_D);CHKERRQ(ierr);
1624     } else {
1625       ierr = VecScale(pcis->vec4_D,m_one);CHKERRQ(ierr);
1626     }
1627     ierr = VecScatterBegin(pcis->global_to_D,pcis->vec4_D,z,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1628     ierr = VecScatterEnd(pcis->global_to_D,pcis->vec4_D,z,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1629   }
1630 
1631   if (pcbddc->benign_saddle_point) { /* set p0 (computed in PCBDDCApplyInterface) */
1632     ierr = PCBDDCBenignGetOrSetP0(pc,z,PETSC_FALSE);CHKERRQ(ierr);
1633   }
1634   PetscFunctionReturn(0);
1635 }
1636 
1637 /* -------------------------------------------------------------------------- */
1638 /*
1639    PCApplyTranspose_BDDC - Applies the transpose of the BDDC operator to a vector.
1640 
1641    Input Parameters:
1642 +  pc - the preconditioner context
1643 -  r - input vector (global)
1644 
1645    Output Parameter:
1646 .  z - output vector (global)
1647 
1648    Application Interface Routine: PCApplyTranspose()
1649  */
1650 #undef __FUNCT__
1651 #define __FUNCT__ "PCApplyTranspose_BDDC"
1652 PetscErrorCode PCApplyTranspose_BDDC(PC pc,Vec r,Vec z)
1653 {
1654   PC_IS             *pcis = (PC_IS*)(pc->data);
1655   PC_BDDC           *pcbddc = (PC_BDDC*)(pc->data);
1656   PetscInt          n_B = pcis->n_B, n_D = pcis->n - n_B;
1657   PetscErrorCode    ierr;
1658   const PetscScalar one = 1.0;
1659   const PetscScalar m_one = -1.0;
1660   const PetscScalar zero = 0.0;
1661 
1662   PetscFunctionBegin;
1663   if (pcbddc->benign_saddle_point) { /* get p0 from r */
1664     ierr = PCBDDCBenignGetOrSetP0(pc,r,PETSC_TRUE);CHKERRQ(ierr);
1665   }
1666   if (!pcbddc->use_exact_dirichlet_trick) {
1667     ierr = VecCopy(r,z);CHKERRQ(ierr);
1668     /* First Dirichlet solve */
1669     ierr = VecScatterBegin(pcis->global_to_D,r,pcis->vec1_D,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1670     ierr = VecScatterEnd(pcis->global_to_D,r,pcis->vec1_D,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1671     /*
1672       Assembling right hand side for BDDC operator
1673       - pcis->vec1_D for the Dirichlet part (if needed, i.e. pcbddc->switch_static == PETSC_TRUE)
1674       - pcis->vec1_B the interface part of the global vector z
1675     */
1676     if (n_D) {
1677       ierr = KSPSolveTranspose(pcbddc->ksp_D,pcis->vec1_D,pcis->vec2_D);CHKERRQ(ierr);
1678       ierr = VecScale(pcis->vec2_D,m_one);CHKERRQ(ierr);
1679       if (pcbddc->switch_static) { ierr = MatMultTransposeAdd(pcis->A_II,pcis->vec2_D,pcis->vec1_D,pcis->vec1_D);CHKERRQ(ierr); }
1680       ierr = MatMultTranspose(pcis->A_IB,pcis->vec2_D,pcis->vec1_B);CHKERRQ(ierr);
1681     } else {
1682       ierr = VecSet(pcis->vec1_B,zero);CHKERRQ(ierr);
1683     }
1684     ierr = VecScatterBegin(pcis->global_to_B,pcis->vec1_B,z,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1685     ierr = VecScatterEnd(pcis->global_to_B,pcis->vec1_B,z,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1686     ierr = PCBDDCScalingRestriction(pc,z,pcis->vec1_B);CHKERRQ(ierr);
1687   } else {
1688     if (pcbddc->switch_static) {
1689       ierr = VecSet(pcis->vec1_D,zero);CHKERRQ(ierr);
1690     }
1691     ierr = PCBDDCScalingRestriction(pc,r,pcis->vec1_B);CHKERRQ(ierr);
1692   }
1693 
1694   /* Apply interface preconditioner
1695      input/output vecs: pcis->vec1_B and pcis->vec1_D */
1696   ierr = PCBDDCApplyInterfacePreconditioner(pc,PETSC_TRUE);CHKERRQ(ierr);
1697 
1698   /* Apply transpose of partition of unity operator */
1699   ierr = PCBDDCScalingExtension(pc,pcis->vec1_B,z);CHKERRQ(ierr);
1700 
1701   /* Second Dirichlet solve and assembling of output */
1702   ierr = VecScatterBegin(pcis->global_to_B,z,pcis->vec1_B,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1703   ierr = VecScatterEnd(pcis->global_to_B,z,pcis->vec1_B,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1704   if (n_B) {
1705     ierr = MatMultTranspose(pcis->A_BI,pcis->vec1_B,pcis->vec3_D);CHKERRQ(ierr);
1706     if (pcbddc->switch_static) { ierr = MatMultTransposeAdd(pcis->A_II,pcis->vec1_D,pcis->vec3_D,pcis->vec3_D);CHKERRQ(ierr); }
1707   } else if (pcbddc->switch_static) {
1708     ierr = MatMultTranspose(pcis->A_II,pcis->vec1_D,pcis->vec3_D);CHKERRQ(ierr);
1709   }
1710   ierr = KSPSolveTranspose(pcbddc->ksp_D,pcis->vec3_D,pcis->vec4_D);CHKERRQ(ierr);
1711   if (!pcbddc->use_exact_dirichlet_trick) {
1712     if (pcbddc->switch_static) {
1713       ierr = VecAXPBYPCZ(pcis->vec2_D,m_one,one,m_one,pcis->vec4_D,pcis->vec1_D);CHKERRQ(ierr);
1714     } else {
1715       ierr = VecAXPBY(pcis->vec2_D,m_one,m_one,pcis->vec4_D);CHKERRQ(ierr);
1716     }
1717     ierr = VecScatterBegin(pcis->global_to_D,pcis->vec2_D,z,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1718     ierr = VecScatterEnd(pcis->global_to_D,pcis->vec2_D,z,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1719   } else {
1720     if (pcbddc->switch_static) {
1721       ierr = VecAXPBY(pcis->vec4_D,one,m_one,pcis->vec1_D);CHKERRQ(ierr);
1722     } else {
1723       ierr = VecScale(pcis->vec4_D,m_one);CHKERRQ(ierr);
1724     }
1725     ierr = VecScatterBegin(pcis->global_to_D,pcis->vec4_D,z,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1726     ierr = VecScatterEnd(pcis->global_to_D,pcis->vec4_D,z,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1727   }
1728   if (pcbddc->benign_saddle_point) { /* set p0 (computed in PCBDDCApplyInterface) */
1729     ierr = PCBDDCBenignGetOrSetP0(pc,z,PETSC_FALSE);CHKERRQ(ierr);
1730   }
1731   PetscFunctionReturn(0);
1732 }
1733 /* -------------------------------------------------------------------------- */
1734 
1735 #undef __FUNCT__
1736 #define __FUNCT__ "PCDestroy_BDDC"
1737 PetscErrorCode PCDestroy_BDDC(PC pc)
1738 {
1739   PC_BDDC        *pcbddc = (PC_BDDC*)pc->data;
1740   PetscErrorCode ierr;
1741 
1742   PetscFunctionBegin;
1743   /* free data created by PCIS */
1744   ierr = PCISDestroy(pc);CHKERRQ(ierr);
1745   /* free BDDC custom data  */
1746   ierr = PCBDDCResetCustomization(pc);CHKERRQ(ierr);
1747   /* destroy objects related to topography */
1748   ierr = PCBDDCResetTopography(pc);CHKERRQ(ierr);
1749   /* free allocated graph structure */
1750   ierr = PetscFree(pcbddc->mat_graph);CHKERRQ(ierr);
1751   /* free allocated sub schurs structure */
1752   ierr = PetscFree(pcbddc->sub_schurs);CHKERRQ(ierr);
1753   /* destroy objects for scaling operator */
1754   ierr = PCBDDCScalingDestroy(pc);CHKERRQ(ierr);
1755   ierr = PetscFree(pcbddc->deluxe_ctx);CHKERRQ(ierr);
1756   /* free solvers stuff */
1757   ierr = PCBDDCResetSolvers(pc);CHKERRQ(ierr);
1758   /* free global vectors needed in presolve */
1759   ierr = VecDestroy(&pcbddc->temp_solution);CHKERRQ(ierr);
1760   ierr = VecDestroy(&pcbddc->original_rhs);CHKERRQ(ierr);
1761   /* free stuff for change of basis hooks */
1762   if (pcbddc->new_global_mat) {
1763     PCBDDCChange_ctx change_ctx;
1764     ierr = MatShellGetContext(pcbddc->new_global_mat,&change_ctx);CHKERRQ(ierr);
1765     ierr = MatDestroy(&change_ctx->original_mat);CHKERRQ(ierr);
1766     ierr = MatDestroy(&change_ctx->global_change);CHKERRQ(ierr);
1767     ierr = VecDestroyVecs(2,&change_ctx->work);CHKERRQ(ierr);
1768     ierr = PetscFree(change_ctx);CHKERRQ(ierr);
1769   }
1770   ierr = MatDestroy(&pcbddc->new_global_mat);CHKERRQ(ierr);
1771   /* remove functions */
1772   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetChangeOfBasisMat_C",NULL);CHKERRQ(ierr);
1773   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetPrimalVerticesLocalIS_C",NULL);CHKERRQ(ierr);
1774   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetCoarseningRatio_C",NULL);CHKERRQ(ierr);
1775   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetLevel_C",NULL);CHKERRQ(ierr);
1776   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetUseExactDirichlet_C",NULL);CHKERRQ(ierr);
1777   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetLevels_C",NULL);CHKERRQ(ierr);
1778   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetNullSpace_C",NULL);CHKERRQ(ierr);
1779   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetDirichletBoundaries_C",NULL);CHKERRQ(ierr);
1780   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetDirichletBoundariesLocal_C",NULL);CHKERRQ(ierr);
1781   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetNeumannBoundaries_C",NULL);CHKERRQ(ierr);
1782   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetNeumannBoundariesLocal_C",NULL);CHKERRQ(ierr);
1783   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCGetDirichletBoundaries_C",NULL);CHKERRQ(ierr);
1784   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCGetDirichletBoundariesLocal_C",NULL);CHKERRQ(ierr);
1785   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCGetNeumannBoundaries_C",NULL);CHKERRQ(ierr);
1786   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCGetNeumannBoundariesLocal_C",NULL);CHKERRQ(ierr);
1787   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetDofsSplitting_C",NULL);CHKERRQ(ierr);
1788   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetDofsSplittingLocal_C",NULL);CHKERRQ(ierr);
1789   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetLocalAdjacencyGraph_C",NULL);CHKERRQ(ierr);
1790   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCCreateFETIDPOperators_C",NULL);CHKERRQ(ierr);
1791   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCMatFETIDPGetRHS_C",NULL);CHKERRQ(ierr);
1792   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCMatFETIDPGetSolution_C",NULL);CHKERRQ(ierr);
1793   /* Free the private data structure */
1794   ierr = PetscFree(pc->data);CHKERRQ(ierr);
1795   PetscFunctionReturn(0);
1796 }
1797 /* -------------------------------------------------------------------------- */
1798 
1799 #undef __FUNCT__
1800 #define __FUNCT__ "PCBDDCMatFETIDPGetRHS_BDDC"
1801 static PetscErrorCode PCBDDCMatFETIDPGetRHS_BDDC(Mat fetidp_mat, Vec standard_rhs, Vec fetidp_flux_rhs)
1802 {
1803   FETIDPMat_ctx  mat_ctx;
1804   Vec            copy_standard_rhs;
1805   PC_IS*         pcis;
1806   PC_BDDC*       pcbddc;
1807   PetscErrorCode ierr;
1808 
1809   PetscFunctionBegin;
1810   ierr = MatShellGetContext(fetidp_mat,&mat_ctx);CHKERRQ(ierr);
1811   pcis = (PC_IS*)mat_ctx->pc->data;
1812   pcbddc = (PC_BDDC*)mat_ctx->pc->data;
1813 
1814   /*
1815      change of basis for physical rhs if needed
1816      It also changes the rhs in case of dirichlet boundaries
1817      TODO: better management when FETIDP will have its own class
1818   */
1819   ierr = VecDuplicate(standard_rhs,&copy_standard_rhs);CHKERRQ(ierr);
1820   ierr = VecCopy(standard_rhs,copy_standard_rhs);CHKERRQ(ierr);
1821   ierr = PCPreSolve_BDDC(mat_ctx->pc,NULL,copy_standard_rhs,NULL);CHKERRQ(ierr);
1822   /* store vectors for computation of fetidp final solution */
1823   ierr = VecScatterBegin(pcis->global_to_D,copy_standard_rhs,mat_ctx->temp_solution_D,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1824   ierr = VecScatterEnd(pcis->global_to_D,copy_standard_rhs,mat_ctx->temp_solution_D,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1825   /* scale rhs since it should be unassembled */
1826   /* TODO use counter scaling? (also below) */
1827   ierr = VecScatterBegin(pcis->global_to_B,copy_standard_rhs,mat_ctx->temp_solution_B,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1828   ierr = VecScatterEnd(pcis->global_to_B,copy_standard_rhs,mat_ctx->temp_solution_B,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1829   /* Apply partition of unity */
1830   ierr = VecPointwiseMult(mat_ctx->temp_solution_B,pcis->D,mat_ctx->temp_solution_B);CHKERRQ(ierr);
1831   /* ierr = PCBDDCScalingRestriction(mat_ctx->pc,copy_standard_rhs,mat_ctx->temp_solution_B);CHKERRQ(ierr); */
1832   if (!pcbddc->switch_static) {
1833     /* compute partially subassembled Schur complement right-hand side */
1834     ierr = KSPSolve(pcbddc->ksp_D,mat_ctx->temp_solution_D,pcis->vec1_D);CHKERRQ(ierr);
1835     ierr = MatMult(pcis->A_BI,pcis->vec1_D,pcis->vec1_B);CHKERRQ(ierr);
1836     ierr = VecAXPY(mat_ctx->temp_solution_B,-1.0,pcis->vec1_B);CHKERRQ(ierr);
1837     ierr = VecSet(copy_standard_rhs,0.0);CHKERRQ(ierr);
1838     ierr = VecScatterBegin(pcis->global_to_B,mat_ctx->temp_solution_B,copy_standard_rhs,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1839     ierr = VecScatterEnd(pcis->global_to_B,mat_ctx->temp_solution_B,copy_standard_rhs,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1840     /* ierr = PCBDDCScalingRestriction(mat_ctx->pc,copy_standard_rhs,mat_ctx->temp_solution_B);CHKERRQ(ierr); */
1841     ierr = VecScatterBegin(pcis->global_to_B,copy_standard_rhs,mat_ctx->temp_solution_B,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1842     ierr = VecScatterEnd(pcis->global_to_B,copy_standard_rhs,mat_ctx->temp_solution_B,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1843     ierr = VecPointwiseMult(mat_ctx->temp_solution_B,pcis->D,mat_ctx->temp_solution_B);CHKERRQ(ierr);
1844   }
1845   ierr = VecDestroy(&copy_standard_rhs);CHKERRQ(ierr);
1846   /* BDDC rhs */
1847   ierr = VecCopy(mat_ctx->temp_solution_B,pcis->vec1_B);CHKERRQ(ierr);
1848   if (pcbddc->switch_static) {
1849     ierr = VecCopy(mat_ctx->temp_solution_D,pcis->vec1_D);CHKERRQ(ierr);
1850   }
1851   /* apply BDDC */
1852   ierr = PCBDDCApplyInterfacePreconditioner(mat_ctx->pc,PETSC_FALSE);CHKERRQ(ierr);
1853   /* Application of B_delta and assembling of rhs for fetidp fluxes */
1854   ierr = VecSet(fetidp_flux_rhs,0.0);CHKERRQ(ierr);
1855   ierr = MatMult(mat_ctx->B_delta,pcis->vec1_B,mat_ctx->lambda_local);CHKERRQ(ierr);
1856   ierr = VecScatterBegin(mat_ctx->l2g_lambda,mat_ctx->lambda_local,fetidp_flux_rhs,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1857   ierr = VecScatterEnd(mat_ctx->l2g_lambda,mat_ctx->lambda_local,fetidp_flux_rhs,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1858   PetscFunctionReturn(0);
1859 }
1860 
1861 #undef __FUNCT__
1862 #define __FUNCT__ "PCBDDCMatFETIDPGetRHS"
1863 /*@
1864  PCBDDCMatFETIDPGetRHS - Compute the right-hand side for FETI-DP linear system using the physical right-hand side
1865 
1866    Collective
1867 
1868    Input Parameters:
1869 +  fetidp_mat      - the FETI-DP matrix object obtained by a call to PCBDDCCreateFETIDPOperators
1870 -  standard_rhs    - the right-hand side of the original linear system
1871 
1872    Output Parameters:
1873 .  fetidp_flux_rhs - the right-hand side for the FETI-DP linear system
1874 
1875    Level: developer
1876 
1877    Notes:
1878 
1879 .seealso: PCBDDC, PCBDDCCreateFETIDPOperators, PCBDDCMatFETIDPGetSolution
1880 @*/
1881 PetscErrorCode PCBDDCMatFETIDPGetRHS(Mat fetidp_mat, Vec standard_rhs, Vec fetidp_flux_rhs)
1882 {
1883   FETIDPMat_ctx  mat_ctx;
1884   PetscErrorCode ierr;
1885 
1886   PetscFunctionBegin;
1887   ierr = MatShellGetContext(fetidp_mat,&mat_ctx);CHKERRQ(ierr);
1888   ierr = PetscTryMethod(mat_ctx->pc,"PCBDDCMatFETIDPGetRHS_C",(Mat,Vec,Vec),(fetidp_mat,standard_rhs,fetidp_flux_rhs));CHKERRQ(ierr);
1889   PetscFunctionReturn(0);
1890 }
1891 /* -------------------------------------------------------------------------- */
1892 
1893 #undef __FUNCT__
1894 #define __FUNCT__ "PCBDDCMatFETIDPGetSolution_BDDC"
1895 static PetscErrorCode PCBDDCMatFETIDPGetSolution_BDDC(Mat fetidp_mat, Vec fetidp_flux_sol, Vec standard_sol)
1896 {
1897   FETIDPMat_ctx  mat_ctx;
1898   PC_IS*         pcis;
1899   PC_BDDC*       pcbddc;
1900   PetscErrorCode ierr;
1901 
1902   PetscFunctionBegin;
1903   ierr = MatShellGetContext(fetidp_mat,&mat_ctx);CHKERRQ(ierr);
1904   pcis = (PC_IS*)mat_ctx->pc->data;
1905   pcbddc = (PC_BDDC*)mat_ctx->pc->data;
1906 
1907   /* apply B_delta^T */
1908   ierr = VecScatterBegin(mat_ctx->l2g_lambda,fetidp_flux_sol,mat_ctx->lambda_local,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1909   ierr = VecScatterEnd  (mat_ctx->l2g_lambda,fetidp_flux_sol,mat_ctx->lambda_local,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1910   ierr = MatMultTranspose(mat_ctx->B_delta,mat_ctx->lambda_local,pcis->vec1_B);CHKERRQ(ierr);
1911   /* compute rhs for BDDC application */
1912   ierr = VecAYPX(pcis->vec1_B,-1.0,mat_ctx->temp_solution_B);CHKERRQ(ierr);
1913   if (pcbddc->switch_static) {
1914     ierr = VecCopy(mat_ctx->temp_solution_D,pcis->vec1_D);CHKERRQ(ierr);
1915   }
1916   /* apply BDDC */
1917   ierr = PCBDDCApplyInterfacePreconditioner(mat_ctx->pc,PETSC_FALSE);CHKERRQ(ierr);
1918   /* put values into standard global vector */
1919   ierr = VecScatterBegin(pcis->global_to_B,pcis->vec1_B,standard_sol,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1920   ierr = VecScatterEnd  (pcis->global_to_B,pcis->vec1_B,standard_sol,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1921   if (!pcbddc->switch_static) {
1922     /* compute values into the interior if solved for the partially subassembled Schur complement */
1923     ierr = MatMult(pcis->A_IB,pcis->vec1_B,pcis->vec1_D);CHKERRQ(ierr);
1924     ierr = VecAXPY(mat_ctx->temp_solution_D,-1.0,pcis->vec1_D);CHKERRQ(ierr);
1925     ierr = KSPSolve(pcbddc->ksp_D,mat_ctx->temp_solution_D,pcis->vec1_D);CHKERRQ(ierr);
1926   }
1927   ierr = VecScatterBegin(pcis->global_to_D,pcis->vec1_D,standard_sol,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1928   ierr = VecScatterEnd  (pcis->global_to_D,pcis->vec1_D,standard_sol,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1929   /* final change of basis if needed
1930      Is also sums the dirichlet part removed during RHS assembling */
1931   ierr = PCPostSolve_BDDC(mat_ctx->pc,NULL,NULL,standard_sol);CHKERRQ(ierr);
1932   PetscFunctionReturn(0);
1933 }
1934 
1935 #undef __FUNCT__
1936 #define __FUNCT__ "PCBDDCMatFETIDPGetSolution"
1937 /*@
1938  PCBDDCMatFETIDPGetSolution - Compute the physical solution using the solution of the FETI-DP linear system
1939 
1940    Collective
1941 
1942    Input Parameters:
1943 +  fetidp_mat      - the FETI-DP matrix obtained by a call to PCBDDCCreateFETIDPOperators
1944 -  fetidp_flux_sol - the solution of the FETI-DP linear system
1945 
1946    Output Parameters:
1947 .  standard_sol    - the solution defined on the physical domain
1948 
1949    Level: developer
1950 
1951    Notes:
1952 
1953 .seealso: PCBDDC, PCBDDCCreateFETIDPOperators, PCBDDCMatFETIDPGetRHS
1954 @*/
1955 PetscErrorCode PCBDDCMatFETIDPGetSolution(Mat fetidp_mat, Vec fetidp_flux_sol, Vec standard_sol)
1956 {
1957   FETIDPMat_ctx  mat_ctx;
1958   PetscErrorCode ierr;
1959 
1960   PetscFunctionBegin;
1961   ierr = MatShellGetContext(fetidp_mat,&mat_ctx);CHKERRQ(ierr);
1962   ierr = PetscTryMethod(mat_ctx->pc,"PCBDDCMatFETIDPGetSolution_C",(Mat,Vec,Vec),(fetidp_mat,fetidp_flux_sol,standard_sol));CHKERRQ(ierr);
1963   PetscFunctionReturn(0);
1964 }
1965 /* -------------------------------------------------------------------------- */
1966 
1967 extern PetscErrorCode FETIDPMatMult(Mat,Vec,Vec);
1968 extern PetscErrorCode FETIDPMatMultTranspose(Mat,Vec,Vec);
1969 extern PetscErrorCode PCBDDCDestroyFETIDPMat(Mat);
1970 extern PetscErrorCode FETIDPPCApply(PC,Vec,Vec);
1971 extern PetscErrorCode FETIDPPCApplyTranspose(PC,Vec,Vec);
1972 extern PetscErrorCode PCBDDCDestroyFETIDPPC(PC);
1973 
1974 #undef __FUNCT__
1975 #define __FUNCT__ "PCBDDCCreateFETIDPOperators_BDDC"
1976 static PetscErrorCode PCBDDCCreateFETIDPOperators_BDDC(PC pc, Mat *fetidp_mat, PC *fetidp_pc)
1977 {
1978 
1979   FETIDPMat_ctx  fetidpmat_ctx;
1980   Mat            newmat;
1981   FETIDPPC_ctx   fetidppc_ctx;
1982   PC             newpc;
1983   MPI_Comm       comm;
1984   PetscErrorCode ierr;
1985 
1986   PetscFunctionBegin;
1987   ierr = PetscObjectGetComm((PetscObject)pc,&comm);CHKERRQ(ierr);
1988   /* FETIDP linear matrix */
1989   ierr = PCBDDCCreateFETIDPMatContext(pc,&fetidpmat_ctx);CHKERRQ(ierr);
1990   ierr = PCBDDCSetupFETIDPMatContext(fetidpmat_ctx);CHKERRQ(ierr);
1991   ierr = MatCreateShell(comm,PETSC_DECIDE,PETSC_DECIDE,fetidpmat_ctx->n_lambda,fetidpmat_ctx->n_lambda,fetidpmat_ctx,&newmat);CHKERRQ(ierr);
1992   ierr = MatShellSetOperation(newmat,MATOP_MULT,(void (*)(void))FETIDPMatMult);CHKERRQ(ierr);
1993   ierr = MatShellSetOperation(newmat,MATOP_MULT_TRANSPOSE,(void (*)(void))FETIDPMatMultTranspose);CHKERRQ(ierr);
1994   ierr = MatShellSetOperation(newmat,MATOP_DESTROY,(void (*)(void))PCBDDCDestroyFETIDPMat);CHKERRQ(ierr);
1995   ierr = MatSetUp(newmat);CHKERRQ(ierr);
1996   /* FETIDP preconditioner */
1997   ierr = PCBDDCCreateFETIDPPCContext(pc,&fetidppc_ctx);CHKERRQ(ierr);
1998   ierr = PCBDDCSetupFETIDPPCContext(newmat,fetidppc_ctx);CHKERRQ(ierr);
1999   ierr = PCCreate(comm,&newpc);CHKERRQ(ierr);
2000   ierr = PCSetType(newpc,PCSHELL);CHKERRQ(ierr);
2001   ierr = PCShellSetContext(newpc,fetidppc_ctx);CHKERRQ(ierr);
2002   ierr = PCShellSetApply(newpc,FETIDPPCApply);CHKERRQ(ierr);
2003   ierr = PCShellSetApplyTranspose(newpc,FETIDPPCApplyTranspose);CHKERRQ(ierr);
2004   ierr = PCShellSetDestroy(newpc,PCBDDCDestroyFETIDPPC);CHKERRQ(ierr);
2005   ierr = PCSetOperators(newpc,newmat,newmat);CHKERRQ(ierr);
2006   ierr = PCSetUp(newpc);CHKERRQ(ierr);
2007   /* return pointers for objects created */
2008   *fetidp_mat=newmat;
2009   *fetidp_pc=newpc;
2010   PetscFunctionReturn(0);
2011 }
2012 
2013 #undef __FUNCT__
2014 #define __FUNCT__ "PCBDDCCreateFETIDPOperators"
2015 /*@
2016  PCBDDCCreateFETIDPOperators - Create FETI-DP operators
2017 
2018    Collective
2019 
2020    Input Parameters:
2021 .  pc - the BDDC preconditioning context (setup should have been called before)
2022 
2023    Output Parameters:
2024 +  fetidp_mat - shell FETI-DP matrix object
2025 -  fetidp_pc  - shell Dirichlet preconditioner for FETI-DP matrix
2026 
2027    Options Database Keys:
2028 .    -fetidp_fullyredundant <false> - use or not a fully redundant set of Lagrange multipliers
2029 
2030    Level: developer
2031 
2032    Notes:
2033      Currently the only operations provided for FETI-DP matrix are MatMult and MatMultTranspose
2034 
2035 .seealso: PCBDDC, PCBDDCMatFETIDPGetRHS, PCBDDCMatFETIDPGetSolution
2036 @*/
2037 PetscErrorCode PCBDDCCreateFETIDPOperators(PC pc, Mat *fetidp_mat, PC *fetidp_pc)
2038 {
2039   PetscErrorCode ierr;
2040 
2041   PetscFunctionBegin;
2042   PetscValidHeaderSpecific(pc,PC_CLASSID,1);
2043   if (pc->setupcalled) {
2044     ierr = PetscUseMethod(pc,"PCBDDCCreateFETIDPOperators_C",(PC,Mat*,PC*),(pc,fetidp_mat,fetidp_pc));CHKERRQ(ierr);
2045   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"You must call PCSetup_BDDC() first \n");
2046   PetscFunctionReturn(0);
2047 }
2048 /* -------------------------------------------------------------------------- */
2049 /*MC
2050    PCBDDC - Balancing Domain Decomposition by Constraints.
2051 
2052    An implementation of the BDDC preconditioner based on
2053 
2054 .vb
2055    [1] C. R. Dohrmann. "An approximate BDDC preconditioner", Numerical Linear Algebra with Applications Volume 14, Issue 2, pages 149-168, March 2007
2056    [2] A. Klawonn and O. B. Widlund. "Dual-Primal FETI Methods for Linear Elasticity", http://cs.nyu.edu/csweb/Research/TechReports/TR2004-855/TR2004-855.pdf
2057    [3] J. Mandel, B. Sousedik, C. R. Dohrmann. "Multispace and Multilevel BDDC", http://arxiv.org/abs/0712.3977
2058    [4] C. Pechstein and C. R. Dohrmann. "Modern domain decomposition methods BDDC, deluxe scaling, and an algebraic approach", Seminar talk, Linz, December 2013, http://people.ricam.oeaw.ac.at/c.pechstein/pechstein-bddc2013.pdf
2059 .ve
2060 
2061    The matrix to be preconditioned (Pmat) must be of type MATIS.
2062 
2063    Currently works with MATIS matrices with local matrices of type MATSEQAIJ, MATSEQBAIJ or MATSEQSBAIJ, either with real or complex numbers.
2064 
2065    It also works with unsymmetric and indefinite problems.
2066 
2067    Unlike 'conventional' interface preconditioners, PCBDDC iterates over all degrees of freedom, not just those on the interface. This allows the use of approximate solvers on the subdomains.
2068 
2069    Approximate local solvers are automatically adapted for singular linear problems (see [1]) if the user has provided the nullspace using PCBDDCSetNullSpace()
2070 
2071    Boundary nodes are split in vertices, edges and faces classes using information from the local to global mapping of dofs and the local connectivity graph of nodes. The latter can be customized by using PCBDDCSetLocalAdjacencyGraph()
2072    Additional information on dofs can be provided by using PCBDDCSetDofsSplitting(), PCBDDCSetDirichletBoundaries(), PCBDDCSetNeumannBoundaries(), and PCBDDCSetPrimalVerticesLocalIS()
2073 
2074    Constraints can be customized by attaching a MatNullSpace object to the MATIS matrix via MatSetNearNullSpace(). Non-singular modes are retained via SVD.
2075 
2076    Change of basis is performed similarly to [2] when requested. When more than one constraint is present on a single connected component (i.e. an edge or a face), a robust method based on local QR factorizations is used.
2077    User defined change of basis can be passed to PCBDDC by using PCBDDCSetChangeOfBasisMat()
2078 
2079    The PETSc implementation also supports multilevel BDDC [3]. Coarse grids are partitioned using a MatPartitioning object.
2080 
2081    Adaptive selection of primal constraints [4] is supported for SPD systems with high-contrast in the coefficients if MUMPS is present. Future versions of the code will also consider using MKL_PARDISO or PASTIX.
2082 
2083    An experimental interface to the FETI-DP method is available. FETI-DP operators could be created using PCBDDCCreateFETIDPOperators(). A stand-alone class for the FETI-DP method will be provided in the next releases.
2084    Deluxe scaling is not supported yet for FETI-DP.
2085 
2086    Options Database Keys (some of them, run with -h for a complete list):
2087 
2088 .    -pc_bddc_use_vertices <true> - use or not vertices in primal space
2089 .    -pc_bddc_use_edges <true> - use or not edges in primal space
2090 .    -pc_bddc_use_faces <false> - use or not faces in primal space
2091 .    -pc_bddc_symmetric <true> - symmetric computation of primal basis functions. Specify false for unsymmetric problems
2092 .    -pc_bddc_use_change_of_basis <false> - use change of basis approach (on edges only)
2093 .    -pc_bddc_use_change_on_faces <false> - use change of basis approach on faces if change of basis has been requested
2094 .    -pc_bddc_switch_static <false> - switches from M_2 (default) to M_3 operator (see reference article [1])
2095 .    -pc_bddc_levels <0> - maximum number of levels for multilevel
2096 .    -pc_bddc_coarsening_ratio <8> - number of subdomains which will be aggregated together at the coarser level (e.g. H/h ratio at the coarser level, significative only in the multilevel case)
2097 .    -pc_bddc_redistribute <0> - size of a subset of processors where the coarse problem will be remapped (the value is ignored if not at the coarsest level)
2098 .    -pc_bddc_use_deluxe_scaling <false> - use deluxe scaling
2099 .    -pc_bddc_schur_layers <-1> - select the economic version of deluxe scaling by specifying the number of layers (-1 corresponds to the original deluxe scaling)
2100 .    -pc_bddc_adaptive_threshold <0.0> - when a value greater than one is specified, adaptive selection of constraints is performed on edges and faces (requires deluxe scaling and MUMPS installed)
2101 -    -pc_bddc_check_level <0> - set verbosity level of debugging output
2102 
2103    Options for Dirichlet, Neumann or coarse solver can be set with
2104 .vb
2105       -pc_bddc_dirichlet_
2106       -pc_bddc_neumann_
2107       -pc_bddc_coarse_
2108 .ve
2109    e.g -pc_bddc_dirichlet_ksp_type richardson -pc_bddc_dirichlet_pc_type gamg. PCBDDC uses by default KPSPREONLY and PCLU.
2110 
2111    When using a multilevel approach, solvers' options at the N-th level (N > 1) can be specified as
2112 .vb
2113       -pc_bddc_dirichlet_lN_
2114       -pc_bddc_neumann_lN_
2115       -pc_bddc_coarse_lN_
2116 .ve
2117    Note that level number ranges from the finest (0) to the coarsest (N).
2118    In order to specify options for the BDDC operators at the coarser levels (and not for the solvers), prepend -pc_bddc_coarse_ or -pc_bddc_coarse_l to the option, e.g.
2119 .vb
2120      -pc_bddc_coarse_pc_bddc_adaptive_threshold 5 -pc_bddc_coarse_l1_pc_bddc_redistribute 3
2121 .ve
2122    will use a threshold of 5 for constraints' selection at the first coarse level and will redistribute the coarse problem of the first coarse level on 3 processors
2123 
2124    Level: intermediate
2125 
2126    Developer notes:
2127 
2128    Contributed by Stefano Zampini
2129 
2130 .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC,  MATIS
2131 M*/
2132 
2133 #undef __FUNCT__
2134 #define __FUNCT__ "PCCreate_BDDC"
2135 PETSC_EXTERN PetscErrorCode PCCreate_BDDC(PC pc)
2136 {
2137   PetscErrorCode      ierr;
2138   PC_BDDC             *pcbddc;
2139 
2140   PetscFunctionBegin;
2141   /* Creates the private data structure for this preconditioner and attach it to the PC object. */
2142   ierr      = PetscNewLog(pc,&pcbddc);CHKERRQ(ierr);
2143   pc->data  = (void*)pcbddc;
2144 
2145   /* create PCIS data structure */
2146   ierr = PCISCreate(pc);CHKERRQ(ierr);
2147 
2148   /* BDDC customization */
2149   pcbddc->use_local_adj       = PETSC_TRUE;
2150   pcbddc->use_vertices        = PETSC_TRUE;
2151   pcbddc->use_edges           = PETSC_TRUE;
2152   pcbddc->use_faces           = PETSC_FALSE;
2153   pcbddc->use_change_of_basis = PETSC_FALSE;
2154   pcbddc->use_change_on_faces = PETSC_FALSE;
2155   pcbddc->switch_static       = PETSC_FALSE;
2156   pcbddc->use_nnsp_true       = PETSC_FALSE;
2157   pcbddc->use_qr_single       = PETSC_FALSE;
2158   pcbddc->symmetric_primal    = PETSC_TRUE;
2159   pcbddc->benign_saddle_point = PETSC_FALSE;
2160   pcbddc->dbg_flag            = 0;
2161   /* private */
2162   pcbddc->local_primal_size          = 0;
2163   pcbddc->local_primal_size_cc       = 0;
2164   pcbddc->local_primal_ref_node      = 0;
2165   pcbddc->local_primal_ref_mult      = 0;
2166   pcbddc->n_vertices                 = 0;
2167   pcbddc->primal_indices_local_idxs  = 0;
2168   pcbddc->recompute_topography       = PETSC_FALSE;
2169   pcbddc->coarse_size                = -1;
2170   pcbddc->new_primal_space           = PETSC_FALSE;
2171   pcbddc->new_primal_space_local     = PETSC_FALSE;
2172   pcbddc->global_primal_indices      = 0;
2173   pcbddc->onearnullspace             = 0;
2174   pcbddc->onearnullvecs_state        = 0;
2175   pcbddc->user_primal_vertices       = 0;
2176   pcbddc->NullSpace                  = 0;
2177   pcbddc->temp_solution              = 0;
2178   pcbddc->original_rhs               = 0;
2179   pcbddc->local_mat                  = 0;
2180   pcbddc->ChangeOfBasisMatrix        = 0;
2181   pcbddc->user_ChangeOfBasisMatrix   = 0;
2182   pcbddc->new_global_mat             = 0;
2183   pcbddc->coarse_vec                 = 0;
2184   pcbddc->coarse_ksp                 = 0;
2185   pcbddc->coarse_phi_B               = 0;
2186   pcbddc->coarse_phi_D               = 0;
2187   pcbddc->coarse_psi_B               = 0;
2188   pcbddc->coarse_psi_D               = 0;
2189   pcbddc->vec1_P                     = 0;
2190   pcbddc->vec1_R                     = 0;
2191   pcbddc->vec2_R                     = 0;
2192   pcbddc->local_auxmat1              = 0;
2193   pcbddc->local_auxmat2              = 0;
2194   pcbddc->R_to_B                     = 0;
2195   pcbddc->R_to_D                     = 0;
2196   pcbddc->ksp_D                      = 0;
2197   pcbddc->ksp_R                      = 0;
2198   pcbddc->NeumannBoundaries          = 0;
2199   pcbddc->NeumannBoundariesLocal     = 0;
2200   pcbddc->DirichletBoundaries        = 0;
2201   pcbddc->DirichletBoundariesLocal   = 0;
2202   pcbddc->user_provided_isfordofs    = PETSC_FALSE;
2203   pcbddc->n_ISForDofs                = 0;
2204   pcbddc->n_ISForDofsLocal           = 0;
2205   pcbddc->ISForDofs                  = 0;
2206   pcbddc->ISForDofsLocal             = 0;
2207   pcbddc->ConstraintMatrix           = 0;
2208   pcbddc->use_exact_dirichlet_trick  = PETSC_TRUE;
2209   pcbddc->coarse_loc_to_glob         = 0;
2210   pcbddc->coarsening_ratio           = 8;
2211   pcbddc->coarse_adj_red             = 0;
2212   pcbddc->current_level              = 0;
2213   pcbddc->max_levels                 = 0;
2214   pcbddc->use_coarse_estimates       = PETSC_FALSE;
2215   pcbddc->redistribute_coarse        = 0;
2216   pcbddc->coarse_subassembling       = 0;
2217   pcbddc->coarse_subassembling_init  = 0;
2218 
2219   /* benign subspace trick */
2220   pcbddc->B0_ncol                    = 0;
2221   pcbddc->B0_cols                    = NULL;
2222   pcbddc->B0_vals                    = NULL;
2223   pcbddc->benign_change              = 0;
2224   pcbddc->benign_vec                 = 0;
2225   pcbddc->benign_original_mat        = 0;
2226   pcbddc->benign_sf                  = 0;
2227   pcbddc->benign_p0_lidx             = -1;
2228   pcbddc->benign_p0_gidx             = -1;
2229   pcbddc->benign_null                = PETSC_FALSE;
2230 
2231   /* create local graph structure */
2232   ierr = PCBDDCGraphCreate(&pcbddc->mat_graph);CHKERRQ(ierr);
2233 
2234   /* scaling */
2235   pcbddc->work_scaling          = 0;
2236   pcbddc->use_deluxe_scaling    = PETSC_FALSE;
2237   pcbddc->faster_deluxe         = PETSC_FALSE;
2238 
2239   /* create sub schurs structure */
2240   ierr = PCBDDCSubSchursCreate(&pcbddc->sub_schurs);CHKERRQ(ierr);
2241   pcbddc->sub_schurs_rebuild     = PETSC_FALSE;
2242   pcbddc->sub_schurs_layers      = -1;
2243   pcbddc->sub_schurs_use_useradj = PETSC_FALSE;
2244 
2245   pcbddc->computed_rowadj = PETSC_FALSE;
2246 
2247   /* adaptivity */
2248   pcbddc->adaptive_threshold      = 0.0;
2249   pcbddc->adaptive_nmax           = 0;
2250   pcbddc->adaptive_nmin           = 0;
2251 
2252   /* function pointers */
2253   pc->ops->apply               = PCApply_BDDC;
2254   pc->ops->applytranspose      = PCApplyTranspose_BDDC;
2255   pc->ops->setup               = PCSetUp_BDDC;
2256   pc->ops->destroy             = PCDestroy_BDDC;
2257   pc->ops->setfromoptions      = PCSetFromOptions_BDDC;
2258   pc->ops->view                = 0;
2259   pc->ops->applyrichardson     = 0;
2260   pc->ops->applysymmetricleft  = 0;
2261   pc->ops->applysymmetricright = 0;
2262   pc->ops->presolve            = PCPreSolve_BDDC;
2263   pc->ops->postsolve           = PCPostSolve_BDDC;
2264 
2265   /* composing function */
2266   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetChangeOfBasisMat_C",PCBDDCSetChangeOfBasisMat_BDDC);CHKERRQ(ierr);
2267   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetPrimalVerticesLocalIS_C",PCBDDCSetPrimalVerticesLocalIS_BDDC);CHKERRQ(ierr);
2268   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetCoarseningRatio_C",PCBDDCSetCoarseningRatio_BDDC);CHKERRQ(ierr);
2269   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetLevel_C",PCBDDCSetLevel_BDDC);CHKERRQ(ierr);
2270   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetUseExactDirichlet_C",PCBDDCSetUseExactDirichlet_BDDC);CHKERRQ(ierr);
2271   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetLevels_C",PCBDDCSetLevels_BDDC);CHKERRQ(ierr);
2272   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetNullSpace_C",PCBDDCSetNullSpace_BDDC);CHKERRQ(ierr);
2273   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetDirichletBoundaries_C",PCBDDCSetDirichletBoundaries_BDDC);CHKERRQ(ierr);
2274   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetDirichletBoundariesLocal_C",PCBDDCSetDirichletBoundariesLocal_BDDC);CHKERRQ(ierr);
2275   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetNeumannBoundaries_C",PCBDDCSetNeumannBoundaries_BDDC);CHKERRQ(ierr);
2276   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetNeumannBoundariesLocal_C",PCBDDCSetNeumannBoundariesLocal_BDDC);CHKERRQ(ierr);
2277   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCGetDirichletBoundaries_C",PCBDDCGetDirichletBoundaries_BDDC);CHKERRQ(ierr);
2278   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCGetDirichletBoundariesLocal_C",PCBDDCGetDirichletBoundariesLocal_BDDC);CHKERRQ(ierr);
2279   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCGetNeumannBoundaries_C",PCBDDCGetNeumannBoundaries_BDDC);CHKERRQ(ierr);
2280   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCGetNeumannBoundariesLocal_C",PCBDDCGetNeumannBoundariesLocal_BDDC);CHKERRQ(ierr);
2281   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetDofsSplitting_C",PCBDDCSetDofsSplitting_BDDC);CHKERRQ(ierr);
2282   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetDofsSplittingLocal_C",PCBDDCSetDofsSplittingLocal_BDDC);CHKERRQ(ierr);
2283   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCSetLocalAdjacencyGraph_C",PCBDDCSetLocalAdjacencyGraph_BDDC);CHKERRQ(ierr);
2284   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCCreateFETIDPOperators_C",PCBDDCCreateFETIDPOperators_BDDC);CHKERRQ(ierr);
2285   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCMatFETIDPGetRHS_C",PCBDDCMatFETIDPGetRHS_BDDC);CHKERRQ(ierr);
2286   ierr = PetscObjectComposeFunction((PetscObject)pc,"PCBDDCMatFETIDPGetSolution_C",PCBDDCMatFETIDPGetSolution_BDDC);CHKERRQ(ierr);
2287   PetscFunctionReturn(0);
2288 }
2289 
2290