:orphan:
# PCASMCreateSubdomains2D
Creates the index sets for the overlapping Schwarz preconditioner, `PCASM`, for a two-dimensional problem on a regular grid.
## Synopsis
```
#include "petscpc.h"
PetscErrorCode PCASMCreateSubdomains2D(PetscInt m, PetscInt n, PetscInt M, PetscInt N, PetscInt dof, PetscInt overlap, PetscInt *Nsub, IS **is, IS **is_local)
```
Not Collective
## Input Parameters
- ***m -*** the number of mesh points in the x direction
- ***n -*** the number of mesh points in the y direction
- ***M -*** the number of subdomains in the x direction
- ***N -*** the number of subdomains in the y direction
- ***dof -*** degrees of freedom per node
- ***overlap -*** overlap in mesh lines
## Output Parameters
- ***Nsub -*** the number of subdomains created
- ***is -*** array of index sets defining overlapping (if overlap > 0) subdomains
- ***is_local -*** array of index sets defining non-overlapping subdomains
## Note
Presently `PCAMSCreateSubdomains2d()` is valid only for sequential
preconditioners. More general related routines are
`PCASMSetTotalSubdomains()` and `PCASMSetLocalSubdomains()`.
## See Also
`PCASM`, `PCASMSetTotalSubdomains()`, `PCASMSetLocalSubdomains()`, `PCASMGetSubKSP()`,
`PCASMSetOverlap()`
## Level
advanced
## Location
src/ksp/pc/impls/asm/asm.c
## Examples
src/ksp/ksp/tutorials/ex8.c
---
[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/ksp/pc/impls/asm/asm.c)
[Index of all PC routines](index.md)
[Table of Contents for all manual pages](/manualpages/index.md)
[Index of all manual pages](/manualpages/singleindex.md)