:orphan:
# KSPPIPEGCRSetUnrollW
Set to `PETSC_TRUE` to use `KSPPIPEGCR` with unrolling of the w vector 
## Synopsis
```
#include "petscksp.h"  
PetscErrorCode KSPPIPEGCRSetUnrollW(KSP ksp, PetscBool unroll_w)
```
Logically Collective


## Input Parameters

- ***ksp -*** the Krylov space context
- ***unroll_w -*** use unrolling





## Options Database Key

- ***-ksp_pipegcr_unroll_w <bool> -*** use unrolling



## See Also
 [](ch_ksp), `KSPPIPEGCR`, `KSPPIPEGCRSetTruncationType()`, `KSPPIPEGCRSetNprealloc()`, `KSPPIPEGCRGetUnrollW()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/impls/gcr/pipegcr/pipegcr.c.html#KSPPIPEGCRSetUnrollW">src/ksp/ksp/impls/gcr/pipegcr/pipegcr.c</A>


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


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