xref: /petsc/src/ksp/pc/impls/bddc/bddcgraph.c (revision 6989cf23719da283ffb2f2b046f65cb16d97424c)
1 #include <petsc/private/petscimpl.h>
2 #include <../src/ksp/pc/impls/bddc/bddcprivate.h>
3 #include <../src/ksp/pc/impls/bddc/bddcstructs.h>
4 
5 #undef __FUNCT__
6 #define __FUNCT__ "PCBDDCGraphGetDirichletDofsB"
7 PetscErrorCode PCBDDCGraphGetDirichletDofsB(PCBDDCGraph graph, IS* dirdofs)
8 {
9   PetscErrorCode ierr;
10 
11   PetscFunctionBegin;
12   if (graph->dirdofsB) {
13     ierr = PetscObjectReference((PetscObject)graph->dirdofsB);CHKERRQ(ierr);
14   } else if (graph->has_dirichlet) {
15     PetscInt i,size;
16     PetscInt *dirdofs_idxs;
17 
18     size = 0;
19     for (i=0;i<graph->nvtxs;i++) {
20       if (graph->count[i] && graph->special_dof[i] == PCBDDCGRAPH_DIRICHLET_MARK) size++;
21     }
22 
23     ierr = PetscMalloc1(size,&dirdofs_idxs);CHKERRQ(ierr);
24     size = 0;
25     for (i=0;i<graph->nvtxs;i++) {
26       if (graph->count[i] && graph->special_dof[i] == PCBDDCGRAPH_DIRICHLET_MARK) dirdofs_idxs[size++] = i;
27     }
28     ierr = ISCreateGeneral(PETSC_COMM_SELF,size,dirdofs_idxs,PETSC_OWN_POINTER,&graph->dirdofsB);CHKERRQ(ierr);
29     ierr = PetscObjectReference((PetscObject)graph->dirdofsB);CHKERRQ(ierr);
30   }
31   *dirdofs = graph->dirdofsB;
32   PetscFunctionReturn(0);
33 }
34 
35 #undef __FUNCT__
36 #define __FUNCT__ "PCBDDCGraphGetDirichletDofs"
37 PetscErrorCode PCBDDCGraphGetDirichletDofs(PCBDDCGraph graph, IS* dirdofs)
38 {
39   PetscErrorCode ierr;
40 
41   PetscFunctionBegin;
42   if (graph->dirdofs) {
43     ierr = PetscObjectReference((PetscObject)graph->dirdofs);CHKERRQ(ierr);
44   } else if (graph->has_dirichlet) {
45     PetscInt i,size;
46     PetscInt *dirdofs_idxs;
47 
48     size = 0;
49     for (i=0;i<graph->nvtxs;i++) {
50       if (graph->special_dof[i] == PCBDDCGRAPH_DIRICHLET_MARK) size++;
51     }
52 
53     ierr = PetscMalloc1(size,&dirdofs_idxs);CHKERRQ(ierr);
54     size = 0;
55     for (i=0;i<graph->nvtxs;i++) {
56       if (graph->special_dof[i] == PCBDDCGRAPH_DIRICHLET_MARK) dirdofs_idxs[size++] = i;
57     }
58     ierr = ISCreateGeneral(PetscObjectComm((PetscObject)graph->l2gmap),size,dirdofs_idxs,PETSC_OWN_POINTER,&graph->dirdofs);CHKERRQ(ierr);
59     ierr = PetscObjectReference((PetscObject)graph->dirdofs);CHKERRQ(ierr);
60   }
61   *dirdofs = graph->dirdofs;
62   PetscFunctionReturn(0);
63 }
64 
65 #undef __FUNCT__
66 #define __FUNCT__ "PCBDDCGraphASCIIView"
67 PetscErrorCode PCBDDCGraphASCIIView(PCBDDCGraph graph, PetscInt verbosity_level, PetscViewer viewer)
68 {
69   PetscInt       i,j,tabs;
70   PetscInt*      queue_in_global_numbering;
71   PetscErrorCode ierr;
72 
73   PetscFunctionBegin;
74   ierr = PetscViewerASCIIPushSynchronized(viewer);CHKERRQ(ierr);
75   ierr = PetscViewerASCIIGetTab(viewer,&tabs);CHKERRQ(ierr);
76   ierr = PetscViewerASCIIPrintf(viewer,"--------------------------------------------------\n");CHKERRQ(ierr);
77   ierr = PetscViewerFlush(viewer);CHKERRQ(ierr);
78   ierr = PetscViewerASCIISynchronizedPrintf(viewer,"Local BDDC graph for subdomain %04d\n",PetscGlobalRank);CHKERRQ(ierr);
79   ierr = PetscViewerASCIISynchronizedPrintf(viewer,"Number of vertices %d\n",graph->nvtxs);CHKERRQ(ierr);
80   ierr = PetscViewerASCIISynchronizedPrintf(viewer,"Custom minimal size %d\n",graph->custom_minimal_size);CHKERRQ(ierr);
81   if (verbosity_level > 2) {
82     for (i=0;i<graph->nvtxs;i++) {
83       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"%d:\n",i);CHKERRQ(ierr);
84       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"   which_dof: %d\n",graph->which_dof[i]);CHKERRQ(ierr);
85       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"   special_dof: %d\n",graph->special_dof[i]);CHKERRQ(ierr);
86       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"   neighbours: %d\n",graph->count[i]);CHKERRQ(ierr);
87       ierr = PetscViewerASCIIUseTabs(viewer,PETSC_FALSE);CHKERRQ(ierr);
88       if (graph->count[i]) {
89         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"     set of neighbours:");CHKERRQ(ierr);
90         for (j=0;j<graph->count[i];j++) {
91           ierr = PetscViewerASCIISynchronizedPrintf(viewer," %d",graph->neighbours_set[i][j]);CHKERRQ(ierr);
92         }
93         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"\n");CHKERRQ(ierr);
94       }
95       ierr = PetscViewerASCIISetTab(viewer,tabs);CHKERRQ(ierr);
96       ierr = PetscViewerASCIIUseTabs(viewer,PETSC_TRUE);CHKERRQ(ierr);
97       if (graph->mirrors) {
98         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"   mirrors: %d\n",graph->mirrors[i]);CHKERRQ(ierr);
99         if (graph->mirrors[i]) {
100           ierr = PetscViewerASCIIUseTabs(viewer,PETSC_FALSE);CHKERRQ(ierr);
101           ierr = PetscViewerASCIISynchronizedPrintf(viewer,"     set of mirrors:");CHKERRQ(ierr);
102           for (j=0;j<graph->mirrors[i];j++) {
103             ierr = PetscViewerASCIISynchronizedPrintf(viewer," %d",graph->mirrors_set[i][j]);CHKERRQ(ierr);
104           }
105           ierr = PetscViewerASCIISynchronizedPrintf(viewer,"\n");CHKERRQ(ierr);
106           ierr = PetscViewerASCIISetTab(viewer,tabs);CHKERRQ(ierr);
107           ierr = PetscViewerASCIIUseTabs(viewer,PETSC_TRUE);CHKERRQ(ierr);
108         }
109       }
110       if (verbosity_level > 3) {
111         if (graph->xadj && graph->adjncy) {
112           ierr = PetscViewerASCIISynchronizedPrintf(viewer,"   local adj list:");CHKERRQ(ierr);
113           ierr = PetscViewerASCIIUseTabs(viewer,PETSC_FALSE);CHKERRQ(ierr);
114           for (j=graph->xadj[i];j<graph->xadj[i+1];j++) {
115             ierr = PetscViewerASCIISynchronizedPrintf(viewer," %d",graph->adjncy[j]);CHKERRQ(ierr);
116           }
117           ierr = PetscViewerASCIISynchronizedPrintf(viewer,"\n");CHKERRQ(ierr);
118           ierr = PetscViewerASCIISetTab(viewer,tabs);CHKERRQ(ierr);
119           ierr = PetscViewerASCIIUseTabs(viewer,PETSC_TRUE);CHKERRQ(ierr);
120         } else {
121           ierr = PetscViewerASCIISynchronizedPrintf(viewer,"   no adj info\n");CHKERRQ(ierr);
122         }
123       }
124       if (graph->n_local_subs) {
125         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"   local sub id: %d\n",graph->local_subs[i]);CHKERRQ(ierr);
126       }
127       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"   interface subset id: %d\n",graph->subset[i]);CHKERRQ(ierr);
128       if (graph->subset[i] && graph->subset_ncc) {
129         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"   ncc for subset: %d\n",graph->subset_ncc[graph->subset[i]-1]);CHKERRQ(ierr);
130       }
131     }
132   }
133   ierr = PetscViewerASCIISynchronizedPrintf(viewer,"Total number of connected components %d\n",graph->ncc);CHKERRQ(ierr);
134   ierr = PetscMalloc1(graph->cptr[graph->ncc],&queue_in_global_numbering);CHKERRQ(ierr);
135   ierr = ISLocalToGlobalMappingApply(graph->l2gmap,graph->cptr[graph->ncc],graph->queue,queue_in_global_numbering);CHKERRQ(ierr);
136   for (i=0;i<graph->ncc;i++) {
137     PetscInt node_num=graph->queue[graph->cptr[i]];
138     PetscBool printcc = PETSC_FALSE;
139     ierr = PetscViewerASCIISynchronizedPrintf(viewer,"  %d (neighs:",i);CHKERRQ(ierr);
140     ierr = PetscViewerASCIIUseTabs(viewer,PETSC_FALSE);CHKERRQ(ierr);
141     for (j=0;j<graph->count[node_num];j++) {
142       ierr = PetscViewerASCIISynchronizedPrintf(viewer," %d",graph->neighbours_set[node_num][j]);CHKERRQ(ierr);
143     }
144     if (verbosity_level > 1) {
145       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"):");CHKERRQ(ierr);
146       if (graph->twodim || graph->count[node_num] > 1 || (graph->count[node_num] == 1 && graph->special_dof[node_num] == PCBDDCGRAPH_NEUMANN_MARK)) {
147         printcc = PETSC_TRUE;
148       }
149       if (printcc) {
150         for (j=graph->cptr[i];j<graph->cptr[i+1];j++) {
151           ierr = PetscViewerASCIISynchronizedPrintf(viewer," %d (%d)",graph->queue[j],queue_in_global_numbering[j]);CHKERRQ(ierr);
152         }
153       }
154     } else {
155       ierr = PetscViewerASCIISynchronizedPrintf(viewer,")");CHKERRQ(ierr);
156     }
157     ierr = PetscViewerASCIISynchronizedPrintf(viewer,"\n");CHKERRQ(ierr);
158     ierr = PetscViewerASCIISetTab(viewer,tabs);CHKERRQ(ierr);
159     ierr = PetscViewerASCIIUseTabs(viewer,PETSC_TRUE);CHKERRQ(ierr);
160   }
161   ierr = PetscFree(queue_in_global_numbering);CHKERRQ(ierr);
162   ierr = PetscViewerFlush(viewer);CHKERRQ(ierr);
163   PetscFunctionReturn(0);
164 }
165 
166 #undef __FUNCT__
167 #define __FUNCT__ "PCBDDCGraphRestoreCandidatesIS"
168 PetscErrorCode PCBDDCGraphRestoreCandidatesIS(PCBDDCGraph graph, PetscInt *n_faces, IS *FacesIS[], PetscInt *n_edges, IS *EdgesIS[], IS *VerticesIS)
169 {
170   PetscInt       i;
171   PetscErrorCode ierr;
172 
173   PetscFunctionBegin;
174   if (n_faces) {
175     if (FacesIS) {
176       for (i=0;i<*n_faces;i++) {
177         ierr = ISDestroy(&((*FacesIS)[i]));CHKERRQ(ierr);
178       }
179       ierr = PetscFree(*FacesIS);CHKERRQ(ierr);
180     }
181     *n_faces = 0;
182   }
183   if (n_edges) {
184     if (EdgesIS) {
185       for (i=0;i<*n_edges;i++) {
186         ierr = ISDestroy(&((*EdgesIS)[i]));CHKERRQ(ierr);
187       }
188       ierr = PetscFree(*EdgesIS);CHKERRQ(ierr);
189     }
190     *n_edges = 0;
191   }
192   if (VerticesIS) {
193     ierr = ISDestroy(VerticesIS);CHKERRQ(ierr);
194   }
195   PetscFunctionReturn(0);
196 }
197 
198 #undef __FUNCT__
199 #define __FUNCT__ "PCBDDCGraphGetCandidatesIS"
200 PetscErrorCode PCBDDCGraphGetCandidatesIS(PCBDDCGraph graph, PetscInt *n_faces, IS *FacesIS[], PetscInt *n_edges, IS *EdgesIS[], IS *VerticesIS)
201 {
202   IS             *ISForFaces,*ISForEdges,ISForVertices;
203   PetscInt       i,nfc,nec,nvc,*idx;
204   PetscErrorCode ierr;
205 
206   PetscFunctionBegin;
207   /* loop on ccs to evalute number of faces, edges and vertices */
208   nfc = 0;
209   nec = 0;
210   nvc = 0;
211   for (i=0;i<graph->ncc;i++) {
212     PetscInt repdof = graph->queue[graph->cptr[i]];
213     if (graph->cptr[i+1]-graph->cptr[i] > graph->custom_minimal_size) {
214       if (graph->count[repdof] == 1 && graph->special_dof[repdof] != PCBDDCGRAPH_NEUMANN_MARK) {
215         nfc++;
216       } else { /* note that nec will be zero in 2d */
217         nec++;
218       }
219     } else {
220       nvc += graph->cptr[i+1]-graph->cptr[i];
221     }
222   }
223 
224   /* check if we are in 2D or 3D */
225   if (graph->twodim) { /* we are in a 2D case -> edges are shared by 2 subregions and faces don't exist */
226     nec = nfc;
227     nfc = 0;
228   }
229 
230   /* allocate IS arrays for faces, edges. Vertices need a single index set. */
231   if (FacesIS) {
232     ierr = PetscMalloc1(nfc,&ISForFaces);CHKERRQ(ierr);
233   }
234   if (EdgesIS) {
235     ierr = PetscMalloc1(nec,&ISForEdges);CHKERRQ(ierr);
236   }
237   if (VerticesIS) {
238     ierr = PetscMalloc1(nvc,&idx);CHKERRQ(ierr);
239   }
240 
241   /* loop on ccs to compute index sets for faces and edges */
242   if (!graph->queue_sorted) {
243     PetscInt *queue_global;
244 
245     ierr = PetscMalloc1(graph->cptr[graph->ncc],&queue_global);CHKERRQ(ierr);
246     ierr = ISLocalToGlobalMappingApply(graph->l2gmap,graph->cptr[graph->ncc],graph->queue,queue_global);CHKERRQ(ierr);
247     for (i=0;i<graph->ncc;i++) {
248       ierr = PetscSortIntWithArray(graph->cptr[i+1]-graph->cptr[i],&queue_global[graph->cptr[i]],&graph->queue[graph->cptr[i]]);CHKERRQ(ierr);
249     }
250     ierr = PetscFree(queue_global);CHKERRQ(ierr);
251     graph->queue_sorted = PETSC_TRUE;
252   }
253   nfc = 0;
254   nec = 0;
255   for (i=0;i<graph->ncc;i++) {
256     PetscInt repdof = graph->queue[graph->cptr[i]];
257     if (graph->cptr[i+1]-graph->cptr[i] > graph->custom_minimal_size) {
258       if (graph->count[repdof] == 1 && graph->special_dof[repdof] != PCBDDCGRAPH_NEUMANN_MARK) {
259         if (graph->twodim) {
260           if (EdgesIS) {
261             ierr = ISCreateGeneral(PETSC_COMM_SELF,graph->cptr[i+1]-graph->cptr[i],&graph->queue[graph->cptr[i]],PETSC_USE_POINTER,&ISForEdges[nec]);CHKERRQ(ierr);
262           }
263           nec++;
264         } else {
265           if (FacesIS) {
266             ierr = ISCreateGeneral(PETSC_COMM_SELF,graph->cptr[i+1]-graph->cptr[i],&graph->queue[graph->cptr[i]],PETSC_USE_POINTER,&ISForFaces[nfc]);CHKERRQ(ierr);
267           }
268           nfc++;
269         }
270       } else {
271         if (EdgesIS) {
272           ierr = ISCreateGeneral(PETSC_COMM_SELF,graph->cptr[i+1]-graph->cptr[i],&graph->queue[graph->cptr[i]],PETSC_USE_POINTER,&ISForEdges[nec]);CHKERRQ(ierr);
273         }
274         nec++;
275       }
276     }
277   }
278   /* index set for vertices */
279   if (VerticesIS) {
280     nvc = 0;
281     for (i=0;i<graph->ncc;i++) {
282       if (graph->cptr[i+1]-graph->cptr[i] <= graph->custom_minimal_size) {
283         PetscInt j;
284 
285         for (j=graph->cptr[i];j<graph->cptr[i+1];j++) {
286           idx[nvc]=graph->queue[j];
287           nvc++;
288         }
289       }
290     }
291     /* sort vertex set (by local ordering) */
292     ierr = PetscSortInt(nvc,idx);CHKERRQ(ierr);
293     ierr = ISCreateGeneral(PETSC_COMM_SELF,nvc,idx,PETSC_OWN_POINTER,&ISForVertices);CHKERRQ(ierr);
294   }
295   /* get back info */
296   if (n_faces) *n_faces = nfc;
297   if (FacesIS) *FacesIS = ISForFaces;
298   if (n_edges) *n_edges = nec;
299   if (EdgesIS) *EdgesIS = ISForEdges;
300   if (VerticesIS) *VerticesIS = ISForVertices;
301   PetscFunctionReturn(0);
302 }
303 
304 #undef __FUNCT__
305 #define __FUNCT__ "PCBDDCGraphComputeConnectedComponents"
306 PetscErrorCode PCBDDCGraphComputeConnectedComponents(PCBDDCGraph graph)
307 {
308   PetscBool      adapt_interface_reduced;
309   MPI_Comm       interface_comm;
310   PetscMPIInt    size;
311   PetscInt       i;
312   PetscBool      twodim;
313   PetscErrorCode ierr;
314 
315   PetscFunctionBegin;
316   /* compute connected components locally */
317   ierr = PetscObjectGetComm((PetscObject)(graph->l2gmap),&interface_comm);CHKERRQ(ierr);
318   ierr = PCBDDCGraphComputeConnectedComponentsLocal(graph);CHKERRQ(ierr);
319   /* check consistency of connected components among neighbouring subdomains -> it adapt them in case it is needed */
320   ierr = MPI_Comm_size(interface_comm,&size);CHKERRQ(ierr);
321   adapt_interface_reduced = PETSC_FALSE;
322   if (size > 1) {
323     PetscInt i;
324     PetscBool adapt_interface = PETSC_FALSE;
325     for (i=0;i<graph->n_subsets;i++) {
326       /* We are not sure that on a given subset of the local interface,
327          with two connected components, the latters be the same among sharing subdomains */
328       if (graph->subset_ncc[i] > 1) {
329         adapt_interface = PETSC_TRUE;
330         break;
331       }
332     }
333     ierr = MPIU_Allreduce(&adapt_interface,&adapt_interface_reduced,1,MPIU_BOOL,MPI_LOR,interface_comm);CHKERRQ(ierr);
334   }
335 
336   if (graph->n_subsets && adapt_interface_reduced) {
337     PetscBT     subset_cc_adapt;
338     MPI_Request *send_requests,*recv_requests;
339     PetscInt    *send_buffer,*recv_buffer;
340     PetscInt    sum_requests,start_of_recv,start_of_send;
341     PetscInt    *cum_recv_counts;
342     PetscInt    *labels;
343     PetscInt    ncc,cum_queue,mss,mns,j,k,s;
344     PetscInt    **refine_buffer=NULL,*private_labels = NULL;
345 
346     ierr = PetscMalloc1(graph->nvtxs,&labels);CHKERRQ(ierr);
347     ierr = PetscMemzero(labels,graph->nvtxs*sizeof(*labels));CHKERRQ(ierr);
348     for (i=0;i<graph->ncc;i++)
349       for (j=graph->cptr[i];j<graph->cptr[i+1];j++)
350         labels[graph->queue[j]] = i;
351 
352     /* allocate some space */
353     ierr = PetscMalloc1(graph->n_subsets+1,&cum_recv_counts);CHKERRQ(ierr);
354     ierr = PetscMemzero(cum_recv_counts,(graph->n_subsets+1)*sizeof(*cum_recv_counts));CHKERRQ(ierr);
355 
356     /* first count how many neighbours per connected component I will receive from */
357     cum_recv_counts[0] = 0;
358     for (i=0;i<graph->n_subsets;i++) cum_recv_counts[i+1] = cum_recv_counts[i]+graph->count[graph->subset_idxs[i][0]];
359     ierr = PetscMalloc1(cum_recv_counts[graph->n_subsets],&recv_buffer);CHKERRQ(ierr);
360     ierr = PetscMalloc2(cum_recv_counts[graph->n_subsets],&send_requests,cum_recv_counts[graph->n_subsets],&recv_requests);CHKERRQ(ierr);
361     for (i=0;i<cum_recv_counts[graph->n_subsets];i++) {
362       send_requests[i] = MPI_REQUEST_NULL;
363       recv_requests[i] = MPI_REQUEST_NULL;
364     }
365 
366     /* exchange with my neighbours the number of my connected components on the subset of interface */
367     sum_requests = 0;
368     for (i=0;i<graph->n_subsets;i++) {
369       PetscMPIInt neigh,tag;
370       PetscInt    count,*neighs;
371 
372       count = graph->count[graph->subset_idxs[i][0]];
373       neighs = graph->neighbours_set[graph->subset_idxs[i][0]];
374       ierr = PetscMPIIntCast(2*graph->subset_ref_node[i],&tag);CHKERRQ(ierr);
375       for (k=0;k<count;k++) {
376         ierr = PetscMPIIntCast(neighs[k],&neigh);CHKERRQ(ierr);
377         ierr = MPI_Isend(&graph->subset_ncc[i],1,MPIU_INT,neigh,tag,interface_comm,&send_requests[sum_requests]);CHKERRQ(ierr);
378         ierr = MPI_Irecv(&recv_buffer[sum_requests],1,MPIU_INT,neigh,tag,interface_comm,&recv_requests[sum_requests]);CHKERRQ(ierr);
379         sum_requests++;
380       }
381     }
382     ierr = MPI_Waitall(sum_requests,recv_requests,MPI_STATUSES_IGNORE);CHKERRQ(ierr);
383     ierr = MPI_Waitall(sum_requests,send_requests,MPI_STATUSES_IGNORE);CHKERRQ(ierr);
384 
385     /* determine the subsets I have to adapt (those having more than 1 cc) */
386     ierr = PetscBTCreate(graph->n_subsets,&subset_cc_adapt);CHKERRQ(ierr);
387     ierr = PetscBTMemzero(graph->n_subsets,subset_cc_adapt);CHKERRQ(ierr);
388     for (i=0;i<graph->n_subsets;i++) {
389       if (graph->subset_ncc[i] > 1) {
390         ierr = PetscBTSet(subset_cc_adapt,i);CHKERRQ(ierr);
391         continue;
392       }
393       for (j=cum_recv_counts[i];j<cum_recv_counts[i+1];j++){
394          if (recv_buffer[j] > 1) {
395           ierr = PetscBTSet(subset_cc_adapt,i);
396           break;
397         }
398       }
399     }
400     ierr = PetscFree(recv_buffer);CHKERRQ(ierr);
401 
402     /* determine send/recv buffers sizes */
403     j = 0;
404     mss = 0;
405     for (i=0;i<graph->n_subsets;i++) {
406       if (PetscBTLookup(subset_cc_adapt,i)) {
407         j += graph->subset_size[i];
408         mss = PetscMax(graph->subset_size[i],mss);
409       }
410     }
411     k = 0;
412     mns = 0;
413     for (i=0;i<graph->n_subsets;i++) {
414       if (PetscBTLookup(subset_cc_adapt,i)) {
415         k += (cum_recv_counts[i+1]-cum_recv_counts[i])*graph->subset_size[i];
416         mns = PetscMax(cum_recv_counts[i+1]-cum_recv_counts[i],mns);
417       }
418     }
419     ierr = PetscMalloc2(j,&send_buffer,k,&recv_buffer);CHKERRQ(ierr);
420 
421     /* fill send buffer (order matters: subset_idxs ordered by global ordering) */
422     j = 0;
423     for (i=0;i<graph->n_subsets;i++)
424       if (PetscBTLookup(subset_cc_adapt,i))
425         for (k=0;k<graph->subset_size[i];k++)
426           send_buffer[j++] = labels[graph->subset_idxs[i][k]];
427 
428     /* now exchange the data */
429     start_of_recv = 0;
430     start_of_send = 0;
431     sum_requests = 0;
432     for (i=0;i<graph->n_subsets;i++) {
433       if (PetscBTLookup(subset_cc_adapt,i)) {
434         PetscMPIInt neigh,tag;
435         PetscInt    size_of_send = graph->subset_size[i];
436 
437         j = graph->subset_idxs[i][0];
438         ierr = PetscMPIIntCast(2*graph->subset_ref_node[i]+1,&tag);CHKERRQ(ierr);
439         for (k=0;k<graph->count[j];k++) {
440           ierr = PetscMPIIntCast(graph->neighbours_set[j][k],&neigh);CHKERRQ(ierr);
441           ierr = MPI_Isend(&send_buffer[start_of_send],size_of_send,MPIU_INT,neigh,tag,interface_comm,&send_requests[sum_requests]);CHKERRQ(ierr);
442           ierr = MPI_Irecv(&recv_buffer[start_of_recv],size_of_send,MPIU_INT,neigh,tag,interface_comm,&recv_requests[sum_requests]);CHKERRQ(ierr);
443           start_of_recv += size_of_send;
444           sum_requests++;
445         }
446         start_of_send += size_of_send;
447       }
448     }
449     ierr = MPI_Waitall(sum_requests,recv_requests,MPI_STATUSES_IGNORE);CHKERRQ(ierr);
450 
451     /* refine connected components */
452     start_of_recv = 0;
453     /* allocate some temporary space */
454     if (mss) {
455       ierr = PetscMalloc1(mss,&refine_buffer);CHKERRQ(ierr);
456       ierr = PetscMalloc2(mss*(mns+1),&refine_buffer[0],mss,&private_labels);CHKERRQ(ierr);
457     }
458     ncc = 0;
459     cum_queue = 0;
460     graph->cptr[0] = 0;
461     for (i=0;i<graph->n_subsets;i++) {
462       if (PetscBTLookup(subset_cc_adapt,i)) {
463         PetscInt subset_counter = 0;
464         PetscInt sharingprocs = cum_recv_counts[i+1]-cum_recv_counts[i]+1; /* count myself */
465         PetscInt buffer_size = graph->subset_size[i];
466 
467         /* compute pointers */
468         for (j=1;j<buffer_size;j++) refine_buffer[j] = refine_buffer[j-1] + sharingprocs;
469         /* analyze contributions from subdomains that share the i-th subset
470            The stricture of refine_buffer is suitable to find intersections of ccs among sharingprocs.
471            supposing the current subset is shared by 3 processes and has dimension 5 with global dofs 0,1,2,3,4 (local 0,4,3,1,2)
472            sharing procs connected components:
473              neigh 0: [0 1 4], [2 3], labels [4,7]  (2 connected components)
474              neigh 1: [0 1], [2 3 4], labels [3 2]  (2 connected components)
475              neigh 2: [0 4], [1], [2 3], labels [1 5 6] (3 connected components)
476            refine_buffer will be filled as:
477              [ 4, 3, 1;
478                4, 2, 1;
479                7, 2, 6;
480                4, 3, 5;
481                7, 2, 6; ];
482            The connected components in local ordering are [0], [1], [2 3], [4] */
483         /* fill temp_buffer */
484         for (k=0;k<buffer_size;k++) refine_buffer[k][0] = labels[graph->subset_idxs[i][k]];
485         for (j=0;j<sharingprocs-1;j++) {
486           for (k=0;k<buffer_size;k++) refine_buffer[k][j+1] = recv_buffer[start_of_recv+k];
487           start_of_recv += buffer_size;
488         }
489         ierr = PetscMemzero(private_labels,buffer_size*sizeof(PetscInt));CHKERRQ(ierr);
490         for (j=0;j<buffer_size;j++) {
491           if (!private_labels[j]) { /* found a new cc  */
492             PetscBool same_set;
493 
494             graph->cptr[ncc] = cum_queue;
495             ncc++;
496             subset_counter++;
497             private_labels[j] = subset_counter;
498             graph->queue[cum_queue++] = graph->subset_idxs[i][j];
499             for (k=j+1;k<buffer_size;k++) { /* check for other nodes in new cc */
500               same_set = PETSC_TRUE;
501               for (s=0;s<sharingprocs;s++) {
502                 if (refine_buffer[j][s] != refine_buffer[k][s]) {
503                   same_set = PETSC_FALSE;
504                   break;
505                 }
506               }
507               if (same_set) {
508                 private_labels[k] = subset_counter;
509                 graph->queue[cum_queue++] = graph->subset_idxs[i][k];
510               }
511             }
512           }
513         }
514         graph->cptr[ncc] = cum_queue;
515         graph->subset_ncc[i] = subset_counter;
516         graph->queue_sorted = PETSC_FALSE;
517       } else { /* this subset does not need to be adapted */
518         ierr = PetscMemcpy(graph->queue+cum_queue,graph->subset_idxs[i],graph->subset_size[i]*sizeof(PetscInt));CHKERRQ(ierr);
519         ncc++;
520         cum_queue += graph->subset_size[i];
521         graph->cptr[ncc] = cum_queue;
522       }
523     }
524     graph->cptr[ncc] = cum_queue;
525     graph->ncc = ncc;
526     if (mss) {
527       ierr = PetscFree2(refine_buffer[0],private_labels);CHKERRQ(ierr);
528       ierr = PetscFree(refine_buffer);CHKERRQ(ierr);
529     }
530     ierr = PetscFree(labels);CHKERRQ(ierr);
531     ierr = MPI_Waitall(sum_requests,send_requests,MPI_STATUSES_IGNORE);CHKERRQ(ierr);
532     ierr = PetscFree2(send_requests,recv_requests);CHKERRQ(ierr);
533     ierr = PetscFree2(send_buffer,recv_buffer);CHKERRQ(ierr);
534     ierr = PetscFree(cum_recv_counts);CHKERRQ(ierr);
535     ierr = PetscBTDestroy(&subset_cc_adapt);CHKERRQ(ierr);
536   }
537 
538   /* Determine if we are in 2D or 3D */
539   twodim  = PETSC_TRUE;
540   for (i=0;i<graph->ncc;i++) {
541     PetscInt repdof = graph->queue[graph->cptr[i]];
542     if (graph->cptr[i+1]-graph->cptr[i] > graph->custom_minimal_size) {
543       if (graph->count[repdof] > 1 || graph->special_dof[repdof] == PCBDDCGRAPH_NEUMANN_MARK) {
544         twodim = PETSC_FALSE;
545         break;
546       }
547     }
548   }
549   ierr = MPIU_Allreduce(&twodim,&graph->twodim,1,MPIU_BOOL,MPI_LAND,PetscObjectComm((PetscObject)graph->l2gmap));CHKERRQ(ierr);
550   PetscFunctionReturn(0);
551 }
552 
553 
554 #undef __FUNCT__
555 #define __FUNCT__ "PCBDDCGraphComputeCC_Private"
556 PETSC_STATIC_INLINE PetscErrorCode PCBDDCGraphComputeCC_Private(PCBDDCGraph graph,PetscInt pid,PetscInt* queue_tip,PetscInt n_prev,PetscInt* n_added)
557 {
558   PetscInt       i,j,n;
559   PetscInt       *xadj = graph->xadj,*adjncy = graph->adjncy;
560   PetscBT        touched = graph->touched;
561   PetscBool      havecsr = (PetscBool)(xadj && adjncy);
562   PetscBool      havesubs = (PetscBool)(!!graph->n_local_subs);
563   PetscErrorCode ierr;
564 
565   PetscFunctionBegin;
566   n = 0;
567   if (havecsr && !havesubs) {
568     for (i=-n_prev;i<0;i++) {
569       PetscInt start_dof = queue_tip[i];
570       for (j=xadj[start_dof];j<xadj[start_dof+1];j++) {
571         PetscInt dof = adjncy[j];
572         if (!PetscBTLookup(touched,dof) && graph->subset[dof] == pid) {
573           ierr = PetscBTSet(touched,dof);CHKERRQ(ierr);
574           queue_tip[n] = dof;
575           n++;
576         }
577       }
578     }
579   } else if (havecsr && havesubs) {
580     PetscInt sid = graph->local_subs[queue_tip[-n_prev]];
581     for (i=-n_prev;i<0;i++) {
582       PetscInt start_dof = queue_tip[i];
583       for (j=xadj[start_dof];j<xadj[start_dof+1];j++) {
584         PetscInt dof = adjncy[j];
585         if (!PetscBTLookup(touched,dof) && graph->subset[dof] == pid && graph->local_subs[dof] == sid) {
586           ierr = PetscBTSet(touched,dof);CHKERRQ(ierr);
587           queue_tip[n] = dof;
588           n++;
589         }
590       }
591     }
592   } else { /* sub info only */
593     PetscInt sid = graph->local_subs[queue_tip[-n_prev]];
594     for (j=0;j<graph->subset_size[pid-1];j++) { /* pid \in [1,graph->n_subsets] */
595       PetscInt dof = graph->subset_idxs[pid-1][j];
596       if (!PetscBTLookup(touched,dof) && graph->subset[dof] == pid && graph->local_subs[dof] == sid) {
597         ierr = PetscBTSet(touched,dof);CHKERRQ(ierr);
598         queue_tip[n] = dof;
599         n++;
600       }
601     }
602   }
603   *n_added = n;
604   PetscFunctionReturn(0);
605 }
606 
607 #undef __FUNCT__
608 #define __FUNCT__ "PCBDDCGraphComputeConnectedComponentsLocal"
609 PetscErrorCode PCBDDCGraphComputeConnectedComponentsLocal(PCBDDCGraph graph)
610 {
611   PetscInt       ncc,cum_queue,n;
612   PetscMPIInt    commsize;
613   PetscErrorCode ierr;
614 
615   PetscFunctionBegin;
616   if (!graph->setupcalled) SETERRQ(PetscObjectComm((PetscObject)graph->l2gmap),PETSC_ERR_ORDER,"PCBDDCGraphSetUp should be called first");
617   /* quiet return if there isn't any local info */
618   if ((!graph->xadj || !graph->adjncy) && !graph->n_local_subs) {
619     PetscFunctionReturn(0);
620   }
621 
622   /* reset any previous search of connected components */
623   ierr = PetscBTMemzero(graph->nvtxs,graph->touched);CHKERRQ(ierr);
624   ierr = MPI_Comm_size(PetscObjectComm((PetscObject)graph->l2gmap),&commsize);CHKERRQ(ierr);
625   if (commsize > graph->commsizelimit) {
626     PetscInt i;
627     for (i=0;i<graph->nvtxs;i++) {
628       if (graph->special_dof[i] == PCBDDCGRAPH_DIRICHLET_MARK || !graph->count[i]) {
629         ierr = PetscBTSet(graph->touched,i);CHKERRQ(ierr);
630       }
631     }
632   }
633 
634   /* begin search for connected components */
635   cum_queue = 0;
636   ncc = 0;
637   for (n=0;n<graph->n_subsets;n++) {
638     PetscInt pid = n+1;  /* partition labeled by 0 is discarded */
639     PetscInt found = 0,prev = 0,first = 0,ncc_pid = 0;
640     while (found != graph->subset_size[n]) {
641       PetscInt added = 0;
642       if (!prev) { /* search for new starting dof */
643         while (PetscBTLookup(graph->touched,graph->subset_idxs[n][first])) first++;
644         ierr = PetscBTSet(graph->touched,graph->subset_idxs[n][first]);CHKERRQ(ierr);
645         graph->queue[cum_queue] = graph->subset_idxs[n][first];
646         graph->cptr[ncc] = cum_queue;
647         prev = 1;
648         cum_queue++;
649         found++;
650         ncc_pid++;
651         ncc++;
652       }
653       ierr = PCBDDCGraphComputeCC_Private(graph,pid,graph->queue + cum_queue,prev,&added);CHKERRQ(ierr);
654       if (!added) {
655         graph->subset_ncc[n] = ncc_pid;
656         graph->cptr[ncc] = cum_queue;
657       }
658       prev = added;
659       found += added;
660       cum_queue += added;
661       if (added && found == graph->subset_size[n]) {
662         graph->subset_ncc[n] = ncc_pid;
663         graph->cptr[ncc] = cum_queue;
664       }
665     }
666   }
667   graph->ncc = ncc;
668   graph->queue_sorted = PETSC_FALSE;
669   PetscFunctionReturn(0);
670 }
671 
672 #undef __FUNCT__
673 #define __FUNCT__ "PCBDDCGraphSetUp"
674 PetscErrorCode PCBDDCGraphSetUp(PCBDDCGraph graph, PetscInt custom_minimal_size, IS neumann_is, IS dirichlet_is, PetscInt n_ISForDofs, IS ISForDofs[], IS custom_primal_vertices)
675 {
676   VecScatter     scatter_ctx;
677   Vec            local_vec,local_vec2,global_vec;
678   IS             to,from,subset,subset_n;
679   MPI_Comm       comm;
680   PetscScalar    *array,*array2;
681   const PetscInt *is_indices;
682   PetscInt       n_neigh,*neigh,*n_shared,**shared,*queue_global;
683   PetscInt       i,j,k,s,total_counts,nodes_touched,is_size;
684   PetscMPIInt    commsize;
685   PetscBool      same_set,mirrors_found;
686   PetscErrorCode ierr;
687 
688   PetscFunctionBegin;
689   graph->has_dirichlet = PETSC_FALSE;
690   if (dirichlet_is) {
691     PetscCheckSameComm(graph->l2gmap,1,dirichlet_is,4);
692     graph->has_dirichlet = PETSC_TRUE;
693   }
694   ierr = PetscObjectGetComm((PetscObject)(graph->l2gmap),&comm);CHKERRQ(ierr);
695   ierr = MPI_Comm_size(comm,&commsize);CHKERRQ(ierr);
696 
697   /* custom_minimal_size */
698   graph->custom_minimal_size = custom_minimal_size;
699   /* get info l2gmap and allocate work vectors  */
700   ierr = ISLocalToGlobalMappingGetInfo(graph->l2gmap,&n_neigh,&neigh,&n_shared,&shared);CHKERRQ(ierr);
701   /* check if we have any local periodic nodes (periodic BCs) */
702   mirrors_found = PETSC_FALSE;
703   if (graph->nvtxs && n_neigh) {
704     for (i=0; i<n_shared[0]; i++) graph->count[shared[0][i]] += 1;
705     for (i=0; i<n_shared[0]; i++) {
706       if (graph->count[shared[0][i]] > 1) {
707         mirrors_found = PETSC_TRUE;
708         break;
709       }
710     }
711   }
712   /* create some workspace objects */
713   local_vec = NULL;
714   local_vec2 = NULL;
715   global_vec = NULL;
716   to = NULL;
717   from = NULL;
718   scatter_ctx = NULL;
719   if (n_ISForDofs || dirichlet_is || neumann_is || custom_primal_vertices) {
720     ierr = VecCreate(PETSC_COMM_SELF,&local_vec);CHKERRQ(ierr);
721     ierr = VecSetSizes(local_vec,PETSC_DECIDE,graph->nvtxs);CHKERRQ(ierr);
722     ierr = VecSetType(local_vec,VECSTANDARD);CHKERRQ(ierr);
723     ierr = VecDuplicate(local_vec,&local_vec2);CHKERRQ(ierr);
724     ierr = VecCreate(comm,&global_vec);CHKERRQ(ierr);
725     ierr = VecSetSizes(global_vec,PETSC_DECIDE,graph->nvtxs_global);CHKERRQ(ierr);
726     ierr = VecSetType(global_vec,VECSTANDARD);CHKERRQ(ierr);
727     ierr = ISCreateStride(PETSC_COMM_SELF,graph->nvtxs,0,1,&to);CHKERRQ(ierr);
728     ierr = ISLocalToGlobalMappingApplyIS(graph->l2gmap,to,&from);CHKERRQ(ierr);
729     ierr = VecScatterCreate(global_vec,from,local_vec,to,&scatter_ctx);CHKERRQ(ierr);
730   } else if (mirrors_found) {
731     ierr = ISCreateStride(PETSC_COMM_SELF,graph->nvtxs,0,1,&to);CHKERRQ(ierr);
732     ierr = ISLocalToGlobalMappingApplyIS(graph->l2gmap,to,&from);CHKERRQ(ierr);
733   }
734   /* compute local mirrors (if any) */
735   if (mirrors_found) {
736     PetscInt *local_indices,*global_indices;
737     /* get arrays of local and global indices */
738     ierr = PetscMalloc1(graph->nvtxs,&local_indices);CHKERRQ(ierr);
739     ierr = ISGetIndices(to,(const PetscInt**)&is_indices);CHKERRQ(ierr);
740     ierr = PetscMemcpy(local_indices,is_indices,graph->nvtxs*sizeof(PetscInt));CHKERRQ(ierr);
741     ierr = ISRestoreIndices(to,(const PetscInt**)&is_indices);CHKERRQ(ierr);
742     ierr = PetscMalloc1(graph->nvtxs,&global_indices);CHKERRQ(ierr);
743     ierr = ISGetIndices(from,(const PetscInt**)&is_indices);CHKERRQ(ierr);
744     ierr = PetscMemcpy(global_indices,is_indices,graph->nvtxs*sizeof(PetscInt));CHKERRQ(ierr);
745     ierr = ISRestoreIndices(from,(const PetscInt**)&is_indices);CHKERRQ(ierr);
746     /* allocate space for mirrors */
747     ierr = PetscMalloc2(graph->nvtxs,&graph->mirrors,graph->nvtxs,&graph->mirrors_set);CHKERRQ(ierr);
748     ierr = PetscMemzero(graph->mirrors,graph->nvtxs*sizeof(PetscInt));CHKERRQ(ierr);
749     graph->mirrors_set[0] = 0;
750 
751     k=0;
752     for (i=0;i<n_shared[0];i++) {
753       j=shared[0][i];
754       if (graph->count[j] > 1) {
755         graph->mirrors[j]++;
756         k++;
757       }
758     }
759     /* allocate space for set of mirrors */
760     ierr = PetscMalloc1(k,&graph->mirrors_set[0]);CHKERRQ(ierr);
761     for (i=1;i<graph->nvtxs;i++)
762       graph->mirrors_set[i]=graph->mirrors_set[i-1]+graph->mirrors[i-1];
763 
764     /* fill arrays */
765     ierr = PetscMemzero(graph->mirrors,graph->nvtxs*sizeof(PetscInt));CHKERRQ(ierr);
766     for (j=0;j<n_shared[0];j++) {
767       i=shared[0][j];
768       if (graph->count[i] > 1)
769         graph->mirrors_set[i][graph->mirrors[i]++]=global_indices[i];
770     }
771     ierr = PetscSortIntWithArray(graph->nvtxs,global_indices,local_indices);CHKERRQ(ierr);
772     for (i=0;i<graph->nvtxs;i++) {
773       if (graph->mirrors[i] > 0) {
774         ierr = PetscFindInt(graph->mirrors_set[i][0],graph->nvtxs,global_indices,&k);CHKERRQ(ierr);
775         j = global_indices[k];
776         while ( k > 0 && global_indices[k-1] == j) k--;
777         for (j=0;j<graph->mirrors[i];j++) {
778           graph->mirrors_set[i][j]=local_indices[k+j];
779         }
780         ierr = PetscSortInt(graph->mirrors[i],graph->mirrors_set[i]);CHKERRQ(ierr);
781       }
782     }
783     ierr = PetscFree(local_indices);CHKERRQ(ierr);
784     ierr = PetscFree(global_indices);CHKERRQ(ierr);
785   }
786   ierr = PetscMemzero(graph->count,graph->nvtxs*sizeof(*graph->count));CHKERRQ(ierr);
787   ierr = ISDestroy(&to);CHKERRQ(ierr);
788   ierr = ISDestroy(&from);CHKERRQ(ierr);
789 
790   /* Count total number of neigh per node */
791   k = 0;
792   for (i=1;i<n_neigh;i++) {
793     k += n_shared[i];
794     for (j=0;j<n_shared[i];j++) {
795       graph->count[shared[i][j]] += 1;
796     }
797   }
798   /* Allocate space for storing the set of neighbours for each node */
799   if (graph->nvtxs) {
800     ierr = PetscMalloc1(k,&graph->neighbours_set[0]);CHKERRQ(ierr);
801   }
802   for (i=1;i<graph->nvtxs;i++) { /* dont count myself */
803     graph->neighbours_set[i]=graph->neighbours_set[i-1]+graph->count[i-1];
804   }
805   /* Get information for sharing subdomains */
806   ierr = PetscMemzero(graph->count,graph->nvtxs*sizeof(*graph->count));CHKERRQ(ierr);
807   for (i=1;i<n_neigh;i++) { /* dont count myself */
808     s = n_shared[i];
809     for (j=0;j<s;j++) {
810       k = shared[i][j];
811       graph->neighbours_set[k][graph->count[k]] = neigh[i];
812       graph->count[k] += 1;
813     }
814   }
815   /* sort set of sharing subdomains */
816   for (i=0;i<graph->nvtxs;i++) {
817     ierr = PetscSortRemoveDupsInt(&graph->count[i],graph->neighbours_set[i]);CHKERRQ(ierr);
818   }
819   /* free memory allocated by ISLocalToGlobalMappingGetInfo */
820   ierr = ISLocalToGlobalMappingRestoreInfo(graph->l2gmap,&n_neigh,&neigh,&n_shared,&shared);CHKERRQ(ierr);
821 
822   /*
823      Get info for dofs splitting
824      User can specify just a subset; an additional field is considered as a complementary field
825   */
826   for (i=0;i<graph->nvtxs;i++) graph->which_dof[i] = n_ISForDofs; /* by default a dof belongs to the complement set */
827   if (n_ISForDofs) {
828     ierr = VecSet(local_vec,-1.0);CHKERRQ(ierr);
829   }
830   for (i=0;i<n_ISForDofs;i++) {
831     ierr = VecGetArray(local_vec,&array);CHKERRQ(ierr);
832     ierr = ISGetLocalSize(ISForDofs[i],&is_size);CHKERRQ(ierr);
833     ierr = ISGetIndices(ISForDofs[i],(const PetscInt**)&is_indices);CHKERRQ(ierr);
834     for (j=0;j<is_size;j++) {
835       if (is_indices[j] > -1 && is_indices[j] < graph->nvtxs) { /* out of bounds indices (if any) are skipped */
836         graph->which_dof[is_indices[j]] = i;
837         array[is_indices[j]] = 1.*i;
838       }
839     }
840     ierr = ISRestoreIndices(ISForDofs[i],(const PetscInt**)&is_indices);CHKERRQ(ierr);
841     ierr = VecRestoreArray(local_vec,&array);CHKERRQ(ierr);
842   }
843   /* Check consistency among neighbours */
844   if (n_ISForDofs) {
845     ierr = VecScatterBegin(scatter_ctx,local_vec,global_vec,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
846     ierr = VecScatterEnd(scatter_ctx,local_vec,global_vec,INSERT_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
847     ierr = VecScatterBegin(scatter_ctx,global_vec,local_vec2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
848     ierr = VecScatterEnd(scatter_ctx,global_vec,local_vec2,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
849     ierr = VecGetArray(local_vec,&array);CHKERRQ(ierr);
850     ierr = VecGetArray(local_vec2,&array2);CHKERRQ(ierr);
851     for (i=0;i<graph->nvtxs;i++){
852       PetscInt field1,field2;
853 
854       field1 = (PetscInt)PetscRealPart(array[i]);
855       field2 = (PetscInt)PetscRealPart(array2[i]);
856       if (field1 != field2) SETERRQ3(comm,PETSC_ERR_USER,"Local node %D have been assigned two different field ids %D and %D at the same time\n",i,field1,field2);
857     }
858     ierr = VecRestoreArray(local_vec,&array);CHKERRQ(ierr);
859     ierr = VecRestoreArray(local_vec2,&array2);CHKERRQ(ierr);
860   }
861   /* Take into account Neumann nodes */
862   if (neumann_is) {
863     ierr = VecSet(local_vec,0.0);CHKERRQ(ierr);
864     ierr = VecGetArray(local_vec,&array);CHKERRQ(ierr);
865     ierr = ISGetLocalSize(neumann_is,&is_size);CHKERRQ(ierr);
866     ierr = ISGetIndices(neumann_is,(const PetscInt**)&is_indices);CHKERRQ(ierr);
867     for (i=0;i<is_size;i++) {
868       if (is_indices[i] > -1 && is_indices[i] < graph->nvtxs) { /* out of bounds indices (if any) are skipped */
869         array[is_indices[i]] = 1.0;
870       }
871     }
872     ierr = ISRestoreIndices(neumann_is,(const PetscInt**)&is_indices);CHKERRQ(ierr);
873     ierr = VecRestoreArray(local_vec,&array);CHKERRQ(ierr);
874     /* Neumann nodes: impose consistency among neighbours */
875     ierr = VecSet(global_vec,0.0);CHKERRQ(ierr);
876     ierr = VecScatterBegin(scatter_ctx,local_vec,global_vec,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
877     ierr = VecScatterEnd(scatter_ctx,local_vec,global_vec,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
878     ierr = VecScatterBegin(scatter_ctx,global_vec,local_vec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
879     ierr = VecScatterEnd(scatter_ctx,global_vec,local_vec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
880     ierr = VecGetArray(local_vec,&array);CHKERRQ(ierr);
881     for (i=0;i<graph->nvtxs;i++) {
882       if (PetscRealPart(array[i]) > 0.1) {
883         graph->special_dof[i] = PCBDDCGRAPH_NEUMANN_MARK;
884       }
885     }
886     ierr = VecRestoreArray(local_vec,&array);CHKERRQ(ierr);
887   }
888   /* Take into account Dirichlet nodes (they overwrite any Neumann boundary node previously set) */
889   if (dirichlet_is) {
890     ierr = VecSet(local_vec,0.0);CHKERRQ(ierr);
891     ierr = VecGetArray(local_vec,&array);CHKERRQ(ierr);
892     ierr = ISGetLocalSize(dirichlet_is,&is_size);CHKERRQ(ierr);
893     ierr = ISGetIndices(dirichlet_is,(const PetscInt**)&is_indices);CHKERRQ(ierr);
894     for (i=0;i<is_size;i++){
895       if (is_indices[i] > -1 && is_indices[i] < graph->nvtxs) { /* out of bounds indices (if any) are skipped */
896         array[is_indices[i]] = 1.0;
897       }
898     }
899     ierr = ISRestoreIndices(dirichlet_is,(const PetscInt**)&is_indices);CHKERRQ(ierr);
900     ierr = VecRestoreArray(local_vec,&array);CHKERRQ(ierr);
901     /* Dirichlet nodes: impose consistency among neighbours */
902     ierr = VecSet(global_vec,0.0);CHKERRQ(ierr);
903     ierr = VecScatterBegin(scatter_ctx,local_vec,global_vec,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
904     ierr = VecScatterEnd(scatter_ctx,local_vec,global_vec,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
905     ierr = VecScatterBegin(scatter_ctx,global_vec,local_vec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
906     ierr = VecScatterEnd(scatter_ctx,global_vec,local_vec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
907     ierr = VecGetArray(local_vec,&array);CHKERRQ(ierr);
908     for (i=0;i<graph->nvtxs;i++) {
909       if (PetscRealPart(array[i]) > 0.1) {
910         if (commsize > graph->commsizelimit) { /* dirichlet nodes treated as internal */
911           ierr = PetscBTSet(graph->touched,i);CHKERRQ(ierr);
912           graph->subset[i] = 0;
913         }
914         graph->special_dof[i] = PCBDDCGRAPH_DIRICHLET_MARK;
915       }
916     }
917     ierr = VecRestoreArray(local_vec,&array);CHKERRQ(ierr);
918   }
919   /* mark local periodic nodes (if any) and adapt CSR graph (if any) */
920   if (graph->mirrors) {
921     for (i=0;i<graph->nvtxs;i++)
922       if (graph->mirrors[i])
923         graph->special_dof[i] = PCBDDCGRAPH_LOCAL_PERIODIC_MARK;
924 
925     if (graph->xadj && graph->adjncy) {
926       PetscInt *new_xadj,*new_adjncy;
927       /* sort CSR graph */
928       for (i=0;i<graph->nvtxs;i++)
929         ierr = PetscSortInt(graph->xadj[i+1]-graph->xadj[i],&graph->adjncy[graph->xadj[i]]);CHKERRQ(ierr);
930 
931       /* adapt local CSR graph in case of local periodicity */
932       k = 0;
933       for (i=0;i<graph->nvtxs;i++)
934         for (j=graph->xadj[i];j<graph->xadj[i+1];j++)
935           k += graph->mirrors[graph->adjncy[j]];
936 
937       ierr = PetscMalloc1(graph->nvtxs+1,&new_xadj);CHKERRQ(ierr);
938       ierr = PetscMalloc1(k+graph->xadj[graph->nvtxs],&new_adjncy);CHKERRQ(ierr);
939       new_xadj[0] = 0;
940       for (i=0;i<graph->nvtxs;i++) {
941         k = graph->xadj[i+1]-graph->xadj[i];
942         ierr = PetscMemcpy(&new_adjncy[new_xadj[i]],&graph->adjncy[graph->xadj[i]],k*sizeof(PetscInt));CHKERRQ(ierr);
943         new_xadj[i+1] = new_xadj[i]+k;
944         for (j=graph->xadj[i];j<graph->xadj[i+1];j++) {
945           k = graph->mirrors[graph->adjncy[j]];
946           ierr = PetscMemcpy(&new_adjncy[new_xadj[i+1]],graph->mirrors_set[graph->adjncy[j]],k*sizeof(PetscInt));CHKERRQ(ierr);
947           new_xadj[i+1] += k;
948         }
949         k = new_xadj[i+1]-new_xadj[i];
950         ierr = PetscSortRemoveDupsInt(&k,&new_adjncy[new_xadj[i]]);CHKERRQ(ierr);
951         new_xadj[i+1] = new_xadj[i]+k;
952       }
953       /* set new CSR into graph */
954       ierr = PetscFree(graph->xadj);CHKERRQ(ierr);
955       ierr = PetscFree(graph->adjncy);CHKERRQ(ierr);
956       graph->xadj = new_xadj;
957       graph->adjncy = new_adjncy;
958     }
959   }
960 
961   /* mark special nodes (if any) -> each will become a single node equivalence class */
962   if (custom_primal_vertices) {
963     ierr = VecSet(local_vec,0.0);CHKERRQ(ierr);
964     ierr = VecGetArray(local_vec,&array);CHKERRQ(ierr);
965     ierr = ISGetLocalSize(custom_primal_vertices,&is_size);CHKERRQ(ierr);
966     ierr = ISGetIndices(custom_primal_vertices,(const PetscInt**)&is_indices);CHKERRQ(ierr);
967     for (i=0;i<is_size;i++){
968       if (is_indices[i] > -1 && is_indices[i] < graph->nvtxs) { /* out of bounds indices (if any) are skipped */
969         array[is_indices[i]] = 1.0;
970       }
971     }
972     ierr = ISRestoreIndices(custom_primal_vertices,(const PetscInt**)&is_indices);CHKERRQ(ierr);
973     ierr = VecRestoreArray(local_vec,&array);CHKERRQ(ierr);
974     /* special nodes: impose consistency among neighbours */
975     ierr = VecSet(global_vec,0.0);CHKERRQ(ierr);
976     ierr = VecScatterBegin(scatter_ctx,local_vec,global_vec,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
977     ierr = VecScatterEnd(scatter_ctx,local_vec,global_vec,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
978     ierr = VecScatterBegin(scatter_ctx,global_vec,local_vec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
979     ierr = VecScatterEnd(scatter_ctx,global_vec,local_vec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
980     ierr = VecGetArray(local_vec,&array);CHKERRQ(ierr);
981     j = 0;
982     for (i=0;i<graph->nvtxs;i++) {
983       if (PetscRealPart(array[i]) > 0.1 && graph->special_dof[i] != PCBDDCGRAPH_DIRICHLET_MARK) {
984         graph->special_dof[i] = PCBDDCGRAPH_SPECIAL_MARK-j;
985         j++;
986       }
987     }
988     ierr = VecRestoreArray(local_vec,&array);CHKERRQ(ierr);
989   }
990 
991   /* mark interior nodes (if commsize > graph->commsizelimit) as touched and belonging to partition number 0 */
992   if (commsize > graph->commsizelimit) {
993     for (i=0;i<graph->nvtxs;i++) {
994       if (!graph->count[i]) {
995         ierr = PetscBTSet(graph->touched,i);CHKERRQ(ierr);
996         graph->subset[i] = 0;
997       }
998     }
999   }
1000 
1001   /* init graph structure and compute default subsets */
1002   nodes_touched = 0;
1003   for (i=0;i<graph->nvtxs;i++) {
1004     if (PetscBTLookup(graph->touched,i)) {
1005       nodes_touched++;
1006     }
1007   }
1008   i = 0;
1009   graph->ncc = 0;
1010   total_counts = 0;
1011 
1012   /* allocated space for queues */
1013   if (commsize == graph->commsizelimit) {
1014     ierr = PetscMalloc2(graph->nvtxs+1,&graph->cptr,graph->nvtxs,&graph->queue);CHKERRQ(ierr);
1015   } else {
1016     PetscInt nused = graph->nvtxs - nodes_touched;
1017     ierr = PetscMalloc2(nused+1,&graph->cptr,nused,&graph->queue);CHKERRQ(ierr);
1018   }
1019 
1020   while (nodes_touched<graph->nvtxs) {
1021     /*  find first untouched node in local ordering */
1022     while (PetscBTLookup(graph->touched,i)) i++;
1023     ierr = PetscBTSet(graph->touched,i);CHKERRQ(ierr);
1024     graph->subset[i] = graph->ncc+1;
1025     graph->cptr[graph->ncc] = total_counts;
1026     graph->queue[total_counts] = i;
1027     total_counts++;
1028     nodes_touched++;
1029     /* now find all other nodes having the same set of sharing subdomains */
1030     for (j=i+1;j<graph->nvtxs;j++) {
1031       /* check for same number of sharing subdomains, dof number and same special mark */
1032       if (!PetscBTLookup(graph->touched,j) && graph->count[i] == graph->count[j] && graph->which_dof[i] == graph->which_dof[j] && graph->special_dof[i] == graph->special_dof[j]) {
1033         /* check for same set of sharing subdomains */
1034         same_set = PETSC_TRUE;
1035         for (k=0;k<graph->count[j];k++){
1036           if (graph->neighbours_set[i][k] != graph->neighbours_set[j][k]) {
1037             same_set = PETSC_FALSE;
1038           }
1039         }
1040         /* I found a friend of mine */
1041         if (same_set) {
1042           ierr = PetscBTSet(graph->touched,j);CHKERRQ(ierr);
1043           graph->subset[j] = graph->ncc+1;
1044           nodes_touched++;
1045           graph->queue[total_counts] = j;
1046           total_counts++;
1047         }
1048       }
1049     }
1050     graph->ncc++;
1051   }
1052   /* set default number of subsets (at this point no info on csr and/or local_subs has been taken into account, so n_subsets = ncc */
1053   graph->n_subsets = graph->ncc;
1054   ierr = PetscMalloc1(graph->n_subsets,&graph->subset_ncc);CHKERRQ(ierr);
1055   for (i=0;i<graph->n_subsets;i++) {
1056     graph->subset_ncc[i] = 1;
1057   }
1058   /* final pointer */
1059   graph->cptr[graph->ncc] = total_counts;
1060 
1061   /* For consistency reasons (among neighbours), I need to sort (by global ordering) each connected component */
1062   /* Get a reference node (min index in global ordering) for each subset for tagging messages */
1063   ierr = PetscMalloc1(graph->ncc,&graph->subset_ref_node);CHKERRQ(ierr);
1064   ierr = PetscMalloc1(graph->cptr[graph->ncc],&queue_global);CHKERRQ(ierr);
1065   ierr = ISLocalToGlobalMappingApply(graph->l2gmap,graph->cptr[graph->ncc],graph->queue,queue_global);CHKERRQ(ierr);
1066   for (j=0;j<graph->ncc;j++) {
1067     ierr = PetscSortIntWithArray(graph->cptr[j+1]-graph->cptr[j],&queue_global[graph->cptr[j]],&graph->queue[graph->cptr[j]]);CHKERRQ(ierr);
1068     graph->subset_ref_node[j] = graph->queue[graph->cptr[j]];
1069   }
1070   ierr = PetscFree(queue_global);CHKERRQ(ierr);
1071   graph->queue_sorted = PETSC_TRUE;
1072   /* save information on subsets (needed when analyzing the connected components) */
1073   if (graph->ncc) {
1074     ierr = PetscMalloc2(graph->ncc,&graph->subset_size,graph->ncc,&graph->subset_idxs);CHKERRQ(ierr);
1075     ierr = PetscMalloc1(graph->cptr[graph->ncc],&graph->subset_idxs[0]);CHKERRQ(ierr);
1076     ierr = PetscMemzero(graph->subset_idxs[0],graph->cptr[graph->ncc]*sizeof(PetscInt));CHKERRQ(ierr);
1077     for (j=1;j<graph->ncc;j++) {
1078       graph->subset_size[j-1] = graph->cptr[j] - graph->cptr[j-1];
1079       graph->subset_idxs[j] = graph->subset_idxs[j-1] + graph->subset_size[j-1];
1080     }
1081     graph->subset_size[graph->ncc-1] = graph->cptr[graph->ncc] - graph->cptr[graph->ncc-1];
1082     ierr = PetscMemcpy(graph->subset_idxs[0],graph->queue,graph->cptr[graph->ncc]*sizeof(PetscInt));CHKERRQ(ierr);
1083   }
1084 
1085   /* renumber reference nodes */
1086   ierr = ISCreateGeneral(PetscObjectComm((PetscObject)(graph->l2gmap)),graph->ncc,graph->subset_ref_node,PETSC_COPY_VALUES,&subset_n);CHKERRQ(ierr);
1087   ierr = ISLocalToGlobalMappingApplyIS(graph->l2gmap,subset_n,&subset);CHKERRQ(ierr);
1088   ierr = ISDestroy(&subset_n);CHKERRQ(ierr);
1089   ierr = ISRenumber(subset,NULL,NULL,&subset_n);CHKERRQ(ierr);
1090   ierr = ISDestroy(&subset);CHKERRQ(ierr);
1091   ierr = ISGetLocalSize(subset_n,&k);CHKERRQ(ierr);
1092   if (k != graph->ncc) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Invalid size of new subset! %D != %D",k,graph->ncc);
1093   ierr = ISGetIndices(subset_n,&is_indices);CHKERRQ(ierr);
1094   ierr = PetscMemcpy(graph->subset_ref_node,is_indices,graph->ncc*sizeof(PetscInt));CHKERRQ(ierr);
1095   ierr = ISRestoreIndices(subset_n,&is_indices);CHKERRQ(ierr);
1096   ierr = ISDestroy(&subset_n);CHKERRQ(ierr);
1097 
1098   /* free workspace */
1099   ierr = VecDestroy(&local_vec);CHKERRQ(ierr);
1100   ierr = VecDestroy(&local_vec2);CHKERRQ(ierr);
1101   ierr = VecDestroy(&global_vec);CHKERRQ(ierr);
1102   ierr = VecScatterDestroy(&scatter_ctx);CHKERRQ(ierr);
1103   graph->setupcalled = PETSC_TRUE;
1104   PetscFunctionReturn(0);
1105 }
1106 
1107 #undef __FUNCT__
1108 #define __FUNCT__ "PCBDDCGraphResetCSR"
1109 PetscErrorCode PCBDDCGraphResetCSR(PCBDDCGraph graph)
1110 {
1111   PetscErrorCode ierr;
1112 
1113   PetscFunctionBegin;
1114   if (graph->freecsr) {
1115     ierr = PetscFree(graph->xadj);CHKERRQ(ierr);
1116     ierr = PetscFree(graph->adjncy);CHKERRQ(ierr);
1117   } else {
1118     graph->xadj = NULL;
1119     graph->adjncy = NULL;
1120   }
1121   graph->freecsr = PETSC_FALSE;
1122   graph->nvtxs_csr = 0;
1123   PetscFunctionReturn(0);
1124 }
1125 
1126 #undef __FUNCT__
1127 #define __FUNCT__ "PCBDDCGraphReset"
1128 PetscErrorCode PCBDDCGraphReset(PCBDDCGraph graph)
1129 {
1130   PetscErrorCode ierr;
1131 
1132   PetscFunctionBegin;
1133   graph->setupcalled = PETSC_FALSE;
1134   ierr = ISLocalToGlobalMappingDestroy(&graph->l2gmap);CHKERRQ(ierr);
1135   ierr = PetscFree(graph->subset_ncc);CHKERRQ(ierr);
1136   ierr = PetscFree(graph->subset_ref_node);CHKERRQ(ierr);
1137   if (graph->nvtxs) {
1138     ierr = PetscFree(graph->neighbours_set[0]);CHKERRQ(ierr);
1139   }
1140   ierr = PetscBTDestroy(&graph->touched);CHKERRQ(ierr);
1141   ierr = PetscFree5(graph->count,
1142                     graph->neighbours_set,
1143                     graph->subset,
1144                     graph->which_dof,
1145                     graph->special_dof);CHKERRQ(ierr);
1146   ierr = PetscFree2(graph->cptr,graph->queue);CHKERRQ(ierr);
1147   if (graph->mirrors) {
1148     ierr = PetscFree(graph->mirrors_set[0]);CHKERRQ(ierr);
1149   }
1150   ierr = PetscFree2(graph->mirrors,graph->mirrors_set);CHKERRQ(ierr);
1151   if (graph->subset_idxs) {
1152     ierr = PetscFree(graph->subset_idxs[0]);CHKERRQ(ierr);
1153   }
1154   ierr = PetscFree2(graph->subset_size,graph->subset_idxs);CHKERRQ(ierr);
1155   ierr = ISDestroy(&graph->dirdofs);CHKERRQ(ierr);
1156   ierr = ISDestroy(&graph->dirdofsB);CHKERRQ(ierr);
1157   if (graph->n_local_subs) {
1158     ierr = PetscFree(graph->local_subs);CHKERRQ(ierr);
1159   }
1160   graph->has_dirichlet = PETSC_FALSE;
1161   graph->nvtxs = 0;
1162   graph->nvtxs_global = 0;
1163   graph->n_subsets = 0;
1164   graph->custom_minimal_size = 1;
1165   graph->n_local_subs = 0;
1166   PetscFunctionReturn(0);
1167 }
1168 
1169 #undef __FUNCT__
1170 #define __FUNCT__ "PCBDDCGraphInit"
1171 PetscErrorCode PCBDDCGraphInit(PCBDDCGraph graph, ISLocalToGlobalMapping l2gmap, PetscInt N)
1172 {
1173   PetscInt       n;
1174   PetscErrorCode ierr;
1175 
1176   PetscFunctionBegin;
1177   PetscValidPointer(graph,1);
1178   PetscValidHeaderSpecific(l2gmap,IS_LTOGM_CLASSID,2);
1179   PetscValidLogicalCollectiveInt(l2gmap,N,3);
1180   /* raise an error if already allocated */
1181   if (graph->nvtxs_global) SETERRQ(PetscObjectComm((PetscObject)l2gmap),PETSC_ERR_PLIB,"BDDCGraph already initialized");
1182   /* set number of vertices */
1183   ierr = PetscObjectReference((PetscObject)l2gmap);CHKERRQ(ierr);
1184   graph->l2gmap = l2gmap;
1185   ierr = ISLocalToGlobalMappingGetSize(l2gmap,&n);CHKERRQ(ierr);
1186   graph->nvtxs = n;
1187   graph->nvtxs_global = N;
1188   /* allocate used space */
1189   ierr = PetscBTCreate(graph->nvtxs,&graph->touched);CHKERRQ(ierr);
1190   ierr = PetscMalloc5(graph->nvtxs,&graph->count,
1191                       graph->nvtxs,&graph->neighbours_set,
1192                       graph->nvtxs,&graph->subset,
1193                       graph->nvtxs,&graph->which_dof,
1194                       graph->nvtxs,&graph->special_dof);CHKERRQ(ierr);
1195   /* zeroes memory */
1196   ierr = PetscMemzero(graph->count,graph->nvtxs*sizeof(PetscInt));CHKERRQ(ierr);
1197   ierr = PetscMemzero(graph->subset,graph->nvtxs*sizeof(PetscInt));CHKERRQ(ierr);
1198   /* use -1 as a default value for which_dof array */
1199   for (n=0;n<graph->nvtxs;n++) graph->which_dof[n] = -1;
1200   ierr = PetscMemzero(graph->special_dof,graph->nvtxs*sizeof(PetscInt));CHKERRQ(ierr);
1201   /* zeroes first pointer to neighbour set */
1202   if (graph->nvtxs) {
1203     graph->neighbours_set[0] = 0;
1204   }
1205   /* zeroes workspace for values of ncc */
1206   graph->subset_ncc = 0;
1207   graph->subset_ref_node = 0;
1208   /* default flag for csr */
1209   graph->freecsr = PETSC_FALSE;
1210   PetscFunctionReturn(0);
1211 }
1212 
1213 #undef __FUNCT__
1214 #define __FUNCT__ "PCBDDCGraphDestroy"
1215 PetscErrorCode PCBDDCGraphDestroy(PCBDDCGraph* graph)
1216 {
1217   PetscErrorCode ierr;
1218 
1219   PetscFunctionBegin;
1220   ierr = PCBDDCGraphReset(*graph);CHKERRQ(ierr);
1221   ierr = PetscFree(*graph);CHKERRQ(ierr);
1222   PetscFunctionReturn(0);
1223 }
1224 
1225 #undef __FUNCT__
1226 #define __FUNCT__ "PCBDDCGraphCreate"
1227 PetscErrorCode PCBDDCGraphCreate(PCBDDCGraph *graph)
1228 {
1229   PCBDDCGraph    new_graph;
1230   PetscErrorCode ierr;
1231 
1232   PetscFunctionBegin;
1233   ierr = PetscNew(&new_graph);CHKERRQ(ierr);
1234   new_graph->custom_minimal_size = 1;
1235   new_graph->commsizelimit = 1;
1236   *graph = new_graph;
1237   PetscFunctionReturn(0);
1238 }
1239