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# PCASMSetTotalSubdomains
Sets the subdomains for all processors for the additive Schwarz preconditioner, `PCASM`. 
## Synopsis
```
#include "petscpc.h" 
PetscErrorCode PCASMSetTotalSubdomains(PC pc, PetscInt N, IS is[], IS is_local[])
```
Collective, all MPI ranks must pass in the same array of `IS`


## Input Parameters

- ***pc -*** the preconditioner context
- ***N  -*** the number of subdomains for all processors
- ***is -*** the index sets that define the subdomains for all processors
(or `NULL` to ask PETSc to determine the subdomains)
- ***is_local -*** the index sets that define the local part of the subdomains for this processor
(or `NULL` to not provide this information)



## Options Database Key

- ***-pc_asm_blocks <blks> -*** Sets total blocks





## Notes
Currently you cannot use this to set the actual subdomains with the argument is or is_local.

By default the `PCASM` preconditioner uses 1 block per processor.

These index sets cannot be destroyed until after completion of the
linear solves for which the `PCASM` preconditioner is being used.

Use `PCASMSetLocalSubdomains()` to set local subdomains.

The `IS` numbering is in the parallel, global numbering of the vector for both is and is_local


## See Also
 `PCASM`, `PCASMSetLocalSubdomains()`, `PCASMSetOverlap()`, `PCASMGetSubKSP()`,
`PCASMCreateSubdomains2D()`, `PCGASM`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/asm/asm.c.html#PCASMSetTotalSubdomains">src/ksp/pc/impls/asm/asm.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex8.c.html">src/ksp/ksp/tutorials/ex8.c</A><BR>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/asm/asm.c.html#PCASMSetTotalSubdomains_ASM">PCASMSetTotalSubdomains_ASM in src/ksp/pc/impls/asm/asm.c</A><BR>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/ksp/pc/impls/asm/asm.c)


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