:orphan:
# PCSPAISetSp
specify a symmetric matrix sparsity pattern in the `PCSPAI` preconditioner 
## Synopsis
```
#include "petscpc.h" 
PetscErrorCode PCSPAISetSp(PC pc, PetscInt sp)
```

## Input Parameters

- ***pc -*** the preconditioner
- ***n -*** 0 or 1



## Note
If A has a symmetric nonzero pattern use -sp 1 to
improve performance by eliminating some communication
in the parallel version. Even if A does not have a
symmetric nonzero pattern -sp 1 may well lead to good
results, but the code will not follow the published
SPAI algorithm exactly.




## See Also
 `PCSPAI`, `PCSetType()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/spai/ispai.c.html#PCSPAISetSp">src/ksp/pc/impls/spai/ispai.c</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/spai/ispai.c.html#PCSPAISetSp_SPAI">PCSPAISetSp_SPAI in src/ksp/pc/impls/spai/ispai.c</A><BR>


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


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