xref: /petsc/src/ksp/pc/impls/bddc/bddcschurs.c (revision 5e8657ed170075d82e3119957ba531ffe97f1ad9)
1 #include <../src/ksp/pc/impls/bddc/bddc.h>
2 #include <../src/ksp/pc/impls/bddc/bddcprivate.h>
3 
4 static PetscErrorCode PCBDDCAdjGetNextLayer_Private(PetscInt*,PetscInt,PetscBT,PetscInt*,PetscInt*,PetscInt*);
5 
6 #undef __FUNCT__
7 #define __FUNCT__ "PCBDDCSubSchursCreate"
8 PetscErrorCode PCBDDCSubSchursCreate(PCBDDCSubSchurs *sub_schurs)
9 {
10   PCBDDCSubSchurs schurs_ctx;
11   PetscErrorCode  ierr;
12 
13   PetscFunctionBegin;
14   ierr = PetscNew(&schurs_ctx);CHKERRQ(ierr);
15   schurs_ctx->n_subs = 0;
16   *sub_schurs = schurs_ctx;
17   PetscFunctionReturn(0);
18 }
19 
20 #undef __FUNCT__
21 #define __FUNCT__ "PCBDDCSubSchursDestroy"
22 PetscErrorCode PCBDDCSubSchursDestroy(PCBDDCSubSchurs *sub_schurs)
23 {
24   PetscErrorCode ierr;
25 
26   PetscFunctionBegin;
27   ierr = PCBDDCSubSchursReset(*sub_schurs);CHKERRQ(ierr);
28   ierr = PetscFree(*sub_schurs);CHKERRQ(ierr);
29   PetscFunctionReturn(0);
30 }
31 
32 #undef __FUNCT__
33 #define __FUNCT__ "PCBDDCSubSchursReset"
34 PetscErrorCode PCBDDCSubSchursReset(PCBDDCSubSchurs sub_schurs)
35 {
36   PetscInt       i;
37   PetscErrorCode ierr;
38 
39   PetscFunctionBegin;
40   for (i=0;i<sub_schurs->n_subs;i++) {
41     ierr = ISDestroy(&sub_schurs->is_AEj_I[i]);CHKERRQ(ierr);
42     ierr = ISDestroy(&sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
43     ierr = MatDestroy(&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
44     ierr = VecDestroy(&sub_schurs->work1[i]);CHKERRQ(ierr);
45     ierr = VecDestroy(&sub_schurs->work2[i]);CHKERRQ(ierr);
46   }
47   if (sub_schurs->n_subs) {
48     ierr = PetscFree5(sub_schurs->is_AEj_I,sub_schurs->is_AEj_B,sub_schurs->S_Ej,sub_schurs->work1,sub_schurs->work2);CHKERRQ(ierr);
49   }
50   sub_schurs->n_subs = 0;
51   PetscFunctionReturn(0);
52 }
53 
54 #undef __FUNCT__
55 #define __FUNCT__ "PCBDDCAdjGetNextLayer_Private"
56 PETSC_STATIC_INLINE PetscErrorCode PCBDDCAdjGetNextLayer_Private(PetscInt* queue_tip,PetscInt n_prev,PetscBT touched,PetscInt* xadj,PetscInt* adjncy,PetscInt* n_added)
57 {
58   PetscInt       i,j,n;
59   PetscErrorCode ierr;
60 
61   PetscFunctionBegin;
62   n = 0;
63   for (i=-n_prev;i<0;i++) {
64     PetscInt start_dof = queue_tip[i];
65     for (j=xadj[start_dof];j<xadj[start_dof+1];j++) {
66       PetscInt dof = adjncy[j];
67       if (!PetscBTLookup(touched,dof)) {
68         ierr = PetscBTSet(touched,dof);CHKERRQ(ierr);
69         queue_tip[n] = dof;
70         n++;
71       }
72     }
73   }
74   *n_added = n;
75   PetscFunctionReturn(0);
76 }
77 
78 #undef __FUNCT__
79 #define __FUNCT__ "PCBDDCSubSchursSetUp"
80 PetscErrorCode PCBDDCSubSchursSetUp(PCBDDCSubSchurs sub_schurs, Mat S, IS is_A_I, IS is_A_B, PetscInt ncc, IS is_cc[], PetscInt xadj[], PetscInt adjncy[], PetscInt nlayers)
81 {
82   Mat                    A_II,A_IB,A_BI,A_BB;
83   Mat                    AE_II,*AE_IE,*AE_EI,*AE_EE;
84   IS                     is_I,*is_subset_B;
85   ISLocalToGlobalMapping BtoNmap;
86   PetscInt               i;
87   PetscBool              is_sorted;
88   PetscErrorCode         ierr;
89 
90   PetscFunctionBegin;
91   ierr = ISSorted(is_A_I,&is_sorted);CHKERRQ(ierr);
92   if (!is_sorted) {
93     SETERRQ(PetscObjectComm((PetscObject)is_A_I),PETSC_ERR_PLIB,"IS for I dofs should be shorted");
94   }
95   ierr = ISSorted(is_A_B,&is_sorted);CHKERRQ(ierr);
96   if (!is_sorted) {
97     SETERRQ(PetscObjectComm((PetscObject)is_A_B),PETSC_ERR_PLIB,"IS for B dofs should be shorted");
98   }
99 
100   /* get Schur complement matrices */
101   ierr = MatSchurComplementGetSubMatrices(S,&A_II,NULL,&A_IB,&A_BI,&A_BB);CHKERRQ(ierr);
102 
103   /* allocate space for schur complements */
104   ierr = PetscMalloc5(ncc,&sub_schurs->is_AEj_I,ncc,&sub_schurs->is_AEj_B,ncc,&sub_schurs->S_Ej,ncc,&sub_schurs->work1,ncc,&sub_schurs->work2);CHKERRQ(ierr);
105   ierr = PetscMalloc4(ncc,&is_subset_B,ncc,&AE_IE,ncc,&AE_EI,ncc,&AE_EE);CHKERRQ(ierr);
106   sub_schurs->n_subs = ncc;
107 
108   /* maps */
109   if (sub_schurs->n_subs && nlayers >= 0 && xadj != NULL && adjncy != NULL) { /* Interior problems can be different from the original one */
110     ISLocalToGlobalMapping ItoNmap;
111     PetscBT                touched;
112     const PetscInt*        idx_B;
113     PetscInt               n_I,n_B,n_local_dofs,n_prev_added,j,layer,*local_numbering;
114 
115     /* get sizes */
116     ierr = ISGetLocalSize(is_A_I,&n_I);CHKERRQ(ierr);
117     ierr = ISGetLocalSize(is_A_B,&n_B);CHKERRQ(ierr);
118 
119     ierr = ISLocalToGlobalMappingCreateIS(is_A_I,&ItoNmap);CHKERRQ(ierr);
120     ierr = PetscMalloc1(n_I+n_B,&local_numbering);CHKERRQ(ierr);
121     ierr = PetscBTCreate(n_I+n_B,&touched);CHKERRQ(ierr);
122     ierr = PetscBTMemzero(n_I+n_B,touched);CHKERRQ(ierr);
123 
124     /* all boundary dofs must be skipped when adding layers */
125     ierr = ISGetIndices(is_A_B,&idx_B);CHKERRQ(ierr);
126     for (j=0;j<n_B;j++) {
127       ierr = PetscBTSet(touched,idx_B[j]);CHKERRQ(ierr);
128     }
129     ierr = PetscMemcpy(local_numbering,idx_B,n_B*sizeof(PetscInt));CHKERRQ(ierr);
130     ierr = ISRestoreIndices(is_A_B,&idx_B);CHKERRQ(ierr);
131 
132     /* add next layers of dofs */
133     n_local_dofs = n_B;
134     n_prev_added = n_B;
135     for (layer=0;layer<nlayers;layer++) {
136       PetscInt n_added;
137       if (n_local_dofs == n_I+n_B) break;
138       if (n_local_dofs > n_I+n_B) {
139         SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Error querying layer %d. Out of bound access (%d > %d)",layer,n_local_dofs,n_I+n_B);
140       }
141       ierr = PCBDDCAdjGetNextLayer_Private(local_numbering+n_local_dofs,n_prev_added,touched,xadj,adjncy,&n_added);CHKERRQ(ierr);
142       n_prev_added = n_added;
143       n_local_dofs += n_added;
144       if (!n_added) break;
145     }
146     ierr = PetscBTDestroy(&touched);CHKERRQ(ierr);
147 
148     /* IS for I dofs in original numbering and in I numbering */
149     ierr = ISCreateGeneral(PetscObjectComm((PetscObject)ItoNmap),n_local_dofs-n_B,local_numbering+n_B,PETSC_COPY_VALUES,&sub_schurs->is_AEj_I[0]);CHKERRQ(ierr);
150     ierr = PetscFree(local_numbering);CHKERRQ(ierr);
151     ierr = ISSort(sub_schurs->is_AEj_I[0]);CHKERRQ(ierr);
152     ierr = ISGlobalToLocalMappingApplyIS(ItoNmap,IS_GTOLM_DROP,sub_schurs->is_AEj_I[0],&is_I);CHKERRQ(ierr);
153     ierr = ISLocalToGlobalMappingDestroy(&ItoNmap);CHKERRQ(ierr);
154 
155     /* II block */
156     ierr = MatGetSubMatrix(A_II,is_I,is_I,MAT_INITIAL_MATRIX,&AE_II);CHKERRQ(ierr);
157   } else {
158     PetscInt n_I;
159 
160     /* IS for I dofs in original numbering */
161     ierr = PetscObjectReference((PetscObject)is_A_I);CHKERRQ(ierr);
162     sub_schurs->is_AEj_I[0] = is_A_I;
163 
164     /* IS for I dofs in I numbering (strided 1) */
165     ierr = ISGetSize(is_A_I,&n_I);CHKERRQ(ierr);
166     ierr = ISCreateStride(PetscObjectComm((PetscObject)is_A_I),n_I,0,1,&is_I);CHKERRQ(ierr);
167 
168     /* II block is the same */
169     ierr = PetscObjectReference((PetscObject)A_II);CHKERRQ(ierr);
170     AE_II = A_II;
171   }
172 
173   /* TODO: just for compatibility with the previous version, needs to be fixed */
174   for (i=1;i<sub_schurs->n_subs;i++) {
175     ierr = PetscObjectReference((PetscObject)sub_schurs->is_AEj_I[0]);CHKERRQ(ierr);
176     sub_schurs->is_AEj_I[i] = sub_schurs->is_AEj_I[0];
177   }
178 
179   /* subsets in original and boundary numbering */
180   ierr = ISLocalToGlobalMappingCreateIS(is_A_B,&BtoNmap);CHKERRQ(ierr);
181   for (i=0;i<sub_schurs->n_subs;i++) {
182     ierr = ISDuplicate(is_cc[i],&sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
183     ierr = ISSort(sub_schurs->is_AEj_B[i]);CHKERRQ(ierr);
184     ierr = ISGlobalToLocalMappingApplyIS(BtoNmap,IS_GTOLM_DROP,sub_schurs->is_AEj_B[i],&is_subset_B[i]);CHKERRQ(ierr);
185   }
186   ierr = ISLocalToGlobalMappingDestroy(&BtoNmap);CHKERRQ(ierr);
187 
188   /* EE block */
189   for (i=0;i<sub_schurs->n_subs;i++) {
190     ierr = MatGetSubMatrix(A_BB,is_subset_B[i],is_subset_B[i],MAT_INITIAL_MATRIX,&AE_EE[i]);CHKERRQ(ierr);
191   }
192   /* IE block */
193   for (i=0;i<sub_schurs->n_subs;i++) {
194     ierr = MatGetSubMatrix(A_IB,is_I,is_subset_B[i],MAT_INITIAL_MATRIX,&AE_IE[i]);CHKERRQ(ierr);
195   }
196   /* EI block */
197   for (i=0;i<sub_schurs->n_subs;i++) {
198     ierr = MatGetSubMatrix(A_BI,is_subset_B[i],is_I,MAT_INITIAL_MATRIX,&AE_EI[i]);CHKERRQ(ierr);
199   }
200 
201   /* setup Schur complements on subset */
202   for (i=0;i<sub_schurs->n_subs;i++) {
203     ierr = MatCreateSchurComplement(AE_II,AE_II,AE_IE[i],AE_EI[i],AE_EE[i],&sub_schurs->S_Ej[i]);CHKERRQ(ierr);
204     ierr = MatCreateVecs(sub_schurs->S_Ej[i],&sub_schurs->work1[i],&sub_schurs->work2[i]);CHKERRQ(ierr);
205     if (AE_II == A_II) { /* we can reuse the same ksp */
206       KSP ksp;
207       ierr = MatSchurComplementGetKSP(S,&ksp);CHKERRQ(ierr);
208       ierr = MatSchurComplementSetKSP(sub_schurs->S_Ej[i],ksp);CHKERRQ(ierr);
209     } else { /* build new ksp object which inherits ksp and pc types from the original one */
210       KSP      origksp,schurksp;
211       PC       origpc,schurpc;
212       KSPType  ksp_type;
213       PCType   pc_type;
214       PetscInt n_internal;
215 
216       ierr = MatSchurComplementGetKSP(S,&origksp);CHKERRQ(ierr);
217       ierr = MatSchurComplementGetKSP(sub_schurs->S_Ej[i],&schurksp);CHKERRQ(ierr);
218       ierr = KSPGetType(origksp,&ksp_type);CHKERRQ(ierr);
219       ierr = KSPSetType(schurksp,ksp_type);CHKERRQ(ierr);
220       ierr = KSPGetPC(schurksp,&schurpc);CHKERRQ(ierr);
221       ierr = KSPGetPC(origksp,&origpc);CHKERRQ(ierr);
222       ierr = PCGetType(origpc,&pc_type);CHKERRQ(ierr);
223       ierr = PCSetType(schurpc,pc_type);CHKERRQ(ierr);
224       ierr = ISGetSize(is_I,&n_internal);CHKERRQ(ierr);
225       if (n_internal) { /* UMFPACK gives error with 0 sized problems */
226         MatSolverPackage solver=NULL;
227         ierr = PCFactorGetMatSolverPackage(origpc,(const MatSolverPackage*)&solver);CHKERRQ(ierr);
228         if (solver) {
229           ierr = PCFactorSetMatSolverPackage(schurpc,solver);CHKERRQ(ierr);
230         }
231       }
232       ierr = KSPSetUp(schurksp);CHKERRQ(ierr);
233     }
234   }
235   /* free */
236   ierr = ISDestroy(&is_I);CHKERRQ(ierr);
237   ierr = MatDestroy(&AE_II);CHKERRQ(ierr);
238   for (i=0;i<sub_schurs->n_subs;i++) {
239     ierr = MatDestroy(&AE_EE[i]);CHKERRQ(ierr);
240     ierr = MatDestroy(&AE_IE[i]);CHKERRQ(ierr);
241     ierr = MatDestroy(&AE_EI[i]);CHKERRQ(ierr);
242     ierr = ISDestroy(&is_subset_B[i]);CHKERRQ(ierr);
243   }
244   ierr = PetscFree4(is_subset_B,AE_IE,AE_EI,AE_EE);CHKERRQ(ierr);
245   PetscFunctionReturn(0);
246 }
247