230   ilink = jac->head;  in SNESSetUp_Multiblock()
231   if (!jac->pmat) {  in SNESSetUp_Multiblock()
232     PetscCall(PetscMalloc1(nsplit,&jac->pmat));  in SNESSetUp_Multiblock()
234       PetscCall(MatCreateSubMatrix(pc->pmat,ilink->is,ilink->is,MAT_INITIAL_MATRIX,&jac->pmat[i]));  in SNESSetUp_Multiblock()
239       PetscCall(MatCreateSubMatrix(pc->pmat,ilink->is,ilink->is,MAT_REUSE_MATRIX,&jac->pmat[i]));  in SNESSetUp_Multiblock()
243   if (jac->realdiagonal) {  in SNESSetUp_Multiblock()
244     ilink = jac->head;  in SNESSetUp_Multiblock()
245     if (!jac->mat) {  in SNESSetUp_Multiblock()
246       PetscCall(PetscMalloc1(nsplit,&jac->mat));  in SNESSetUp_Multiblock()
248         PetscCall(MatCreateSubMatrix(pc->mat,ilink->is,ilink->is,MAT_INITIAL_MATRIX,&jac->mat[i]));  in SNESSetUp_Multiblock()
253 …if (jac->mat[i]) PetscCall(MatCreateSubMatrix(pc->mat,ilink->is,ilink->is,MAT_REUSE_MATRIX,&jac->m…  in SNESSetUp_Multiblock()
257   } else jac->mat = jac->pmat;  in SNESSetUp_Multiblock()
261   if (jac->type != PC_COMPOSITE_ADDITIVE  && jac->type != PC_COMPOSITE_SCHUR) {  in SNESSetUp_Multiblock()
263     ilink = jac->head;  in SNESSetUp_Multiblock()
264     if (!jac->Afield) {  in SNESSetUp_Multiblock()
265       PetscCall(PetscMalloc1(nsplit,&jac->Afield));  in SNESSetUp_Multiblock()
267         PetscCall(MatCreateSubMatrix(pc->mat,ilink->is,NULL,MAT_INITIAL_MATRIX,&jac->Afield[i]));  in SNESSetUp_Multiblock()
272         PetscCall(MatCreateSubMatrix(pc->mat,ilink->is,NULL,MAT_REUSE_MATRIX,&jac->Afield[i]));  in SNESSetUp_Multiblock()
289     if (jac->schur) {  in SNESSetUp_Multiblock()
290       ilink = jac->head;  in SNESSetUp_Multiblock()
292       PetscCall(MatCreateSubMatrix(pc->mat,ilink->is,ccis,MAT_REUSE_MATRIX,&jac->B));  in SNESSetUp_Multiblock()
296       PetscCall(MatCreateSubMatrix(pc->mat,ilink->is,ccis,MAT_REUSE_MATRIX,&jac->C));  in SNESSetUp_Multiblock()
298 …PetscCall(MatSchurComplementUpdateSubMatrices(jac->schur,jac->mat[0],jac->pmat[0],jac->B,jac->C,ja…  in SNESSetUp_Multiblock()
299       PetscCall(KSPSetOperators(jac->kspschur,jac->schur,FieldSplitSchurPre(jac),pc->flag));  in SNESSetUp_Multiblock()
306       ilink = jac->head;  in SNESSetUp_Multiblock()
308       PetscCall(MatCreateSubMatrix(pc->mat,ilink->is,ccis,MAT_INITIAL_MATRIX,&jac->B));  in SNESSetUp_Multiblock()
312       PetscCall(MatCreateSubMatrix(pc->mat,ilink->is,ccis,MAT_INITIAL_MATRIX,&jac->C));  in SNESSetUp_Multiblock()
315 …PetscCall(MatCreateSchurComplement(jac->mat[0],jac->pmat[0],jac->B,jac->C,jac->mat[1],&jac->schur)…  in SNESSetUp_Multiblock()
317       PetscCall(MatSchurComplementGetKSP(jac->schur,&ksp));  in SNESSetUp_Multiblock()
319 …sfieldsplit_%s_",((PetscObject)pc)->prefix ? ((PetscObject)pc)->prefix : "",jac->head->splitname));  in SNESSetUp_Multiblock()
321       PetscCall(MatSetFromOptions(jac->schur));  in SNESSetUp_Multiblock()
323       PetscCall(KSPCreate(PetscObjectComm((PetscObject)pc),&jac->kspschur));  in SNESSetUp_Multiblock()
324       PetscCall(PetscObjectIncrementTabLevel((PetscObject)jac->kspschur,(PetscObject)pc,1));  in SNESSetUp_Multiblock()
325       PetscCall(KSPSetOperators(jac->kspschur,jac->schur,FieldSplitSchurPre(jac)));  in SNESSetUp_Multiblock()
326       if (jac->schurpre == PC_FIELDSPLIT_SCHUR_PRE_SELF) {  in SNESSetUp_Multiblock()
328         PetscCall(KSPGetPC(jac->kspschur,&pc));  in SNESSetUp_Multiblock()
333       PetscCall(KSPSetOptionsPrefix(jac->kspschur,schurprefix));  in SNESSetUp_Multiblock()
335       PetscCall(KSPSetFromOptions(jac->kspschur));  in SNESSetUp_Multiblock()
337       PetscCall(PetscMalloc2(2,&jac->x,2,&jac->y));  in SNESSetUp_Multiblock()
338       PetscCall(MatCreateVecs(jac->pmat[0],&jac->x[0],&jac->y[0]));  in SNESSetUp_Multiblock()
339       PetscCall(MatCreateVecs(jac->pmat[1],&jac->x[1],&jac->y[1]));  in SNESSetUp_Multiblock()
340       ilink    = jac->head;  in SNESSetUp_Multiblock()
341       ilink->x = jac->x[0]; ilink->y = jac->y[0];  in SNESSetUp_Multiblock()
343       ilink->x = jac->x[1]; ilink->y = jac->y[1];  in SNESSetUp_Multiblock()