Actual source code: packm.c

petsc-3.13.6 2020-09-29
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  2:  #include <../src/dm/impls/composite/packimpl.h>

  4: static PetscErrorCode DMCreateMatrix_Composite_Nest(DM dm,Mat *J)
  5: {
  6:   const DM_Composite           *com = (DM_Composite*)dm->data;
  7:   const struct DMCompositeLink *rlink,*clink;
  8:   PetscErrorCode               ierr;
  9:   IS                           *isg;
 10:   Mat                          *submats;
 11:   PetscInt                     i,j,n;

 14:   n = com->nDM;                 /* Total number of entries */

 16:   /* Explicit index sets are not required for MatCreateNest, but getting them here allows MatNest to do consistency
 17:    * checking and allows ISEqual to compare by identity instead of by contents. */
 18:   DMCompositeGetGlobalISs(dm,&isg);

 20:   /* Get submatrices */
 21:   PetscMalloc1(n*n,&submats);
 22:   for (i=0,rlink=com->next; rlink; i++,rlink=rlink->next) {
 23:     for (j=0,clink=com->next; clink; j++,clink=clink->next) {
 24:       Mat sub = NULL;
 25:       if (i == j) {
 26:         DMCreateMatrix(rlink->dm,&sub);
 27:       } else if (com->FormCoupleLocations) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_SUP,"Cannot manage off-diagonal parts yet");
 28:       submats[i*n+j] = sub;
 29:     }
 30:   }

 32:   MatCreateNest(PetscObjectComm((PetscObject)dm),n,isg,n,isg,submats,J);

 34:   /* Disown references */
 35:   for (i=0; i<n; i++) {ISDestroy(&isg[i]);}
 36:   PetscFree(isg);

 38:   for (i=0; i<n*n; i++) {
 39:     if (submats[i]) {MatDestroy(&submats[i]);}
 40:   }
 41:   PetscFree(submats);
 42:   return(0);
 43: }

 45: static PetscErrorCode DMCreateMatrix_Composite_AIJ(DM dm,Mat *J)
 46: {
 47:   PetscErrorCode         ierr;
 48:   DM_Composite           *com = (DM_Composite*)dm->data;
 49:   struct DMCompositeLink *next;
 50:   PetscInt               m,*dnz,*onz,i,j,mA;
 51:   Mat                    Atmp;
 52:   PetscMPIInt            rank;
 53:   PetscBool              dense = PETSC_FALSE;

 56:   /* use global vector to determine layout needed for matrix */
 57:   m = com->n;

 59:   MatCreate(PetscObjectComm((PetscObject)dm),J);
 60:   MatSetSizes(*J,m,m,PETSC_DETERMINE,PETSC_DETERMINE);
 61:   MatSetType(*J,dm->mattype);

 63:   /*
 64:      Extremely inefficient but will compute entire Jacobian for testing
 65:   */
 66:   PetscOptionsGetBool(((PetscObject)dm)->options,((PetscObject)dm)->prefix,"-dmcomposite_dense_jacobian",&dense,NULL);
 67:   if (dense) {
 68:     PetscInt    rstart,rend,*indices;
 69:     PetscScalar *values;

 71:     mA   = com->N;
 72:     MatMPIAIJSetPreallocation(*J,mA,NULL,mA-m,NULL);
 73:     MatSeqAIJSetPreallocation(*J,mA,NULL);

 75:     MatGetOwnershipRange(*J,&rstart,&rend);
 76:     PetscMalloc2(mA,&values,mA,&indices);
 77:     PetscArrayzero(values,mA);
 78:     for (i=0; i<mA; i++) indices[i] = i;
 79:     for (i=rstart; i<rend; i++) {
 80:       MatSetValues(*J,1,&i,mA,indices,values,INSERT_VALUES);
 81:     }
 82:     PetscFree2(values,indices);
 83:     MatAssemblyBegin(*J,MAT_FINAL_ASSEMBLY);
 84:     MatAssemblyEnd(*J,MAT_FINAL_ASSEMBLY);
 85:     return(0);
 86:   }

 88:   MPI_Comm_rank(PetscObjectComm((PetscObject)dm),&rank);
 89:   MatPreallocateInitialize(PetscObjectComm((PetscObject)dm),m,m,dnz,onz);
 90:   /* loop over packed objects, handling one at at time */
 91:   next = com->next;
 92:   while (next) {
 93:     PetscInt       nc,rstart,*ccols,maxnc;
 94:     const PetscInt *cols,*rstarts;
 95:     PetscMPIInt    proc;

 97:     DMCreateMatrix(next->dm,&Atmp);
 98:     MatGetOwnershipRange(Atmp,&rstart,NULL);
 99:     MatGetOwnershipRanges(Atmp,&rstarts);
100:     MatGetLocalSize(Atmp,&mA,NULL);

102:     maxnc = 0;
103:     for (i=0; i<mA; i++) {
104:       MatGetRow(Atmp,rstart+i,&nc,NULL,NULL);
105:       MatRestoreRow(Atmp,rstart+i,NULL,NULL,NULL);
106:       maxnc = PetscMax(nc,maxnc);
107:     }
108:     PetscMalloc1(maxnc,&ccols);
109:     for (i=0; i<mA; i++) {
110:       MatGetRow(Atmp,rstart+i,&nc,&cols,NULL);
111:       /* remap the columns taking into how much they are shifted on each process */
112:       for (j=0; j<nc; j++) {
113:         proc = 0;
114:         while (cols[j] >= rstarts[proc+1]) proc++;
115:         ccols[j] = cols[j] + next->grstarts[proc] - rstarts[proc];
116:       }
117:       MatPreallocateSet(com->rstart+next->rstart+i,nc,ccols,dnz,onz);
118:       MatRestoreRow(Atmp,rstart+i,&nc,&cols,NULL);
119:     }
120:     PetscFree(ccols);
121:     MatDestroy(&Atmp);
122:     next = next->next;
123:   }
124:   if (com->FormCoupleLocations) {
125:     (*com->FormCoupleLocations)(dm,NULL,dnz,onz,__rstart,__nrows,__start,__end);
126:   }
127:   MatMPIAIJSetPreallocation(*J,0,dnz,0,onz);
128:   MatSeqAIJSetPreallocation(*J,0,dnz);
129:   MatPreallocateFinalize(dnz,onz);

131:   if (dm->prealloc_only) return(0);

133:   next = com->next;
134:   while (next) {
135:     PetscInt          nc,rstart,row,maxnc,*ccols;
136:     const PetscInt    *cols,*rstarts;
137:     const PetscScalar *values;
138:     PetscMPIInt       proc;

140:     DMCreateMatrix(next->dm,&Atmp);
141:     MatGetOwnershipRange(Atmp,&rstart,NULL);
142:     MatGetOwnershipRanges(Atmp,&rstarts);
143:     MatGetLocalSize(Atmp,&mA,NULL);
144:     maxnc = 0;
145:     for (i=0; i<mA; i++) {
146:       MatGetRow(Atmp,rstart+i,&nc,NULL,NULL);
147:       maxnc = PetscMax(nc,maxnc);
148:       MatRestoreRow(Atmp,rstart+i,&nc,NULL,NULL);
149:     }
150:     PetscMalloc1(maxnc,&ccols);
151:     for (i=0; i<mA; i++) {
152:       MatGetRow(Atmp,rstart+i,&nc,(const PetscInt**)&cols,&values);
153:       for (j=0; j<nc; j++) {
154:         proc = 0;
155:         while (cols[j] >= rstarts[proc+1]) proc++;
156:         ccols[j] = cols[j] + next->grstarts[proc] - rstarts[proc];
157:       }
158:       row  = com->rstart+next->rstart+i;
159:       MatSetValues(*J,1,&row,nc,ccols,values,INSERT_VALUES);
160:       MatRestoreRow(Atmp,rstart+i,&nc,(const PetscInt**)&cols,&values);
161:     }
162:     PetscFree(ccols);
163:     MatDestroy(&Atmp);
164:     next = next->next;
165:   }
166:   if (com->FormCoupleLocations) {
167:     PetscInt __rstart;
168:     MatGetOwnershipRange(*J,&__rstart,NULL);
169:     (*com->FormCoupleLocations)(dm,*J,NULL,NULL,__rstart,0,0,0);
170:   }
171:   MatAssemblyBegin(*J,MAT_FINAL_ASSEMBLY);
172:   MatAssemblyEnd(*J,MAT_FINAL_ASSEMBLY);
173:   return(0);
174: }

176: PetscErrorCode DMCreateMatrix_Composite(DM dm,Mat *J)
177: {
178:   PetscErrorCode         ierr;
179:   PetscBool              usenest;
180:   ISLocalToGlobalMapping ltogmap;

183:   DMSetFromOptions(dm);
184:   DMSetUp(dm);
185:   PetscStrcmp(dm->mattype,MATNEST,&usenest);
186:   if (usenest) {
187:     DMCreateMatrix_Composite_Nest(dm,J);
188:   } else {
189:     DMCreateMatrix_Composite_AIJ(dm,J);
190:   }

192:   DMGetLocalToGlobalMapping(dm,&ltogmap);
193:   MatSetLocalToGlobalMapping(*J,ltogmap,ltogmap);
194:   MatSetDM(*J,dm);
195:   return(0);
196: }