510   Mat       sub;  in MatNestFindNonzeroSubMatRow()  local
513   sub = (row < vs->nc) ? vs->m[row][row] : (Mat)NULL; /* Prefer to find on the diagonal */  in MatNestFindNonzeroSubMatRow()
514   for (j = 0; !sub && j < vs->nc; j++) sub = vs->m[row][j];  in MatNestFindNonzeroSubMatRow()
515   if (sub) PetscCall(MatSetUp(sub)); /* Ensure that the sizes are available */  in MatNestFindNonzeroSubMatRow()
516   *B = sub;  in MatNestFindNonzeroSubMatRow()
524   Mat       sub;  in MatNestFindNonzeroSubMatCol()  local
527   sub = (col < vs->nr) ? vs->m[col][col] : (Mat)NULL; /* Prefer to find on the diagonal */  in MatNestFindNonzeroSubMatCol()
528   for (i = 0; !sub && i < vs->nr; i++) sub = vs->m[i][col];  in MatNestFindNonzeroSubMatCol()
529   if (sub) PetscCall(MatSetUp(sub)); /* Ensure that the sizes are available */  in MatNestFindNonzeroSubMatCol()
530   *B = sub;  in MatNestFindNonzeroSubMatCol()
687   Mat       sub;  in MatCreateSubMatrix_Nest()  local
690   PetscCall(MatNestFindSubMat(A, &vs->isglobal, isrow, iscol, &sub));  in MatCreateSubMatrix_Nest()
693     PetscCall(PetscObjectReference((PetscObject)sub));  in MatCreateSubMatrix_Nest()
694     if (sub) PetscCall(PetscObjectStateIncrease((PetscObject)sub));  in MatCreateSubMatrix_Nest()
695     *B = sub;  in MatCreateSubMatrix_Nest()
698 …PetscCheck(sub == *B, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Submatrix was no…  in MatCreateSubMatrix_Nest()
699     if (sub) PetscCall(PetscObjectStateIncrease((PetscObject)sub));  in MatCreateSubMatrix_Nest()
710   Mat       sub;  in MatGetLocalSubMatrix_Nest()  local
713   PetscCall(MatNestFindSubMat(A, &vs->islocal, isrow, iscol, &sub));  in MatGetLocalSubMatrix_Nest()
715   if (sub) PetscCall(PetscObjectReference((PetscObject)sub));  in MatGetLocalSubMatrix_Nest()
716   *B = sub;  in MatGetLocalSubMatrix_Nest()
723   Mat       sub;  in MatRestoreLocalSubMatrix_Nest()  local
726   PetscCall(MatNestFindSubMat(A, &vs->islocal, isrow, iscol, &sub));  in MatRestoreLocalSubMatrix_Nest()
727 …PetscCheck(*B == sub, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Local submatrix …  in MatRestoreLocalSubMatrix_Nest()
728   if (sub) {  in MatRestoreLocalSubMatrix_Nest()
729 …PetscCheck(((PetscObject)sub)->refct > 1, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTAT…  in MatRestoreLocalSubMatrix_Nest()
1089 PetscErrorCode MatNestGetSubMat(Mat A, PetscInt idxm, PetscInt jdxm, Mat *sub)  in MatNestGetSubMat()  argument
1095   PetscAssertPointer(sub, 4);  in MatNestGetSubMat()
1096   PetscUseMethod(A, "MatNestGetSubMat_C", (Mat, PetscInt, PetscInt, Mat *), (A, idxm, jdxm, sub));  in MatNestGetSubMat()
1153 PetscErrorCode MatNestSetSubMat(Mat A, PetscInt idxm, PetscInt jdxm, Mat sub)  in MatNestSetSubMat()  argument
1159   if (sub) PetscValidHeaderSpecific(sub, MAT_CLASSID, 4);  in MatNestSetSubMat()
1160   PetscTryMethod(A, "MatNestSetSubMat_C", (Mat, PetscInt, PetscInt, Mat), (A, idxm, jdxm, sub));  in MatNestSetSubMat()
1520     Mat                    sub  = NULL;  in MatNestCreateAggregateL2G_Private()  local
1526       PetscCall(MatNestFindNonzeroSubMatRow(A, i, &sub));  in MatNestCreateAggregateL2G_Private()
1528       PetscCall(MatNestFindNonzeroSubMatCol(A, i, &sub));  in MatNestCreateAggregateL2G_Private()
1530     if (sub) {  in MatNestCreateAggregateL2G_Private()
1532         PetscCall(MatGetLocalToGlobalMapping(sub, &smap, NULL));  in MatNestCreateAggregateL2G_Private()
1534         PetscCall(MatGetLocalToGlobalMapping(sub, NULL, &smap));  in MatNestCreateAggregateL2G_Private()
1605   Mat       sub = NULL;  in MatSetUp_NestIS_Private()  local
1619       PetscCall(MatNestFindNonzeroSubMatRow(A, i, &sub));  in MatSetUp_NestIS_Private()
1620 …PetscCheck(sub, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "No nonzero submatrix in row…  in MatSetUp_NestIS_Private()
1621       PetscCall(MatGetLocalSize(sub, &n, NULL));  in MatSetUp_NestIS_Private()
1628       PetscCall(MatNestFindNonzeroSubMatRow(A, i, &sub));  in MatSetUp_NestIS_Private()
1629       PetscCall(MatGetLocalSize(sub, &n, NULL));  in MatSetUp_NestIS_Private()
1630       PetscCall(MatGetBlockSizes(sub, &bs, NULL));  in MatSetUp_NestIS_Private()
1631 …  PetscCall(ISCreateStride(PetscObjectComm((PetscObject)sub), n, offset, 1, &vs->isglobal.row[i]));  in MatSetUp_NestIS_Private()
1647       PetscCall(MatNestFindNonzeroSubMatCol(A, j, &sub));  in MatSetUp_NestIS_Private()
1648 …PetscCheck(sub, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "No nonzero submatrix in col…  in MatSetUp_NestIS_Private()
1649       PetscCall(MatGetLocalSize(sub, NULL, &n));  in MatSetUp_NestIS_Private()
1656       PetscCall(MatNestFindNonzeroSubMatCol(A, j, &sub));  in MatSetUp_NestIS_Private()
1657       PetscCall(MatGetLocalSize(sub, NULL, &n));  in MatSetUp_NestIS_Private()
1658       PetscCall(MatGetBlockSizes(sub, NULL, &bs));  in MatSetUp_NestIS_Private()
1659 …  PetscCall(ISCreateStride(PetscObjectComm((PetscObject)sub), n, offset, 1, &vs->isglobal.col[j]));  in MatSetUp_NestIS_Private()
1672     PetscCall(MatNestFindNonzeroSubMatRow(A, i, &sub));  in MatSetUp_NestIS_Private()
1673     if (sub) PetscCall(MatGetLocalToGlobalMapping(sub, &rmap, NULL));  in MatSetUp_NestIS_Private()
1675       PetscCall(MatGetBlockSizes(sub, &bs, NULL));  in MatSetUp_NestIS_Private()
1690     PetscCall(MatNestFindNonzeroSubMatCol(A, i, &sub));  in MatSetUp_NestIS_Private()
1691     if (sub) PetscCall(MatGetLocalToGlobalMapping(sub, NULL, &cmap));  in MatSetUp_NestIS_Private()
1693       PetscCall(MatGetBlockSizes(sub, NULL, &bs));  in MatSetUp_NestIS_Private()
1727 …PetscCheck(M == Mi && N == Ni, PetscObjectComm((PetscObject)sub), PETSC_ERR_ARG_INCOMP, "Global si…  in MatSetUp_NestIS_Private()
1728 …PetscCheck(m == mi && n == ni, PetscObjectComm((PetscObject)sub), PETSC_ERR_ARG_INCOMP, "Local siz…  in MatSetUp_NestIS_Private()