# KSPGMRESSetPreAllocateVectors

Causes GMRES and FGMRES to preallocate all its needed work vectors at initial setup rather than the default, which is to allocate them in chunks when needed.

### Synopsis

    #include "petscksp.h"
    PetscErrorCode PETSCKSP_DLLEXPORT KSPGMRESSetPreAllocateVectors(KSP ksp)

Collective on KSP

### Input Parameter

ksp -iterative context obtained from KSPCreate

### Options Database Key

-ksp_gmres_preallocate -Activates KSPGmresSetPreAllocateVectors()

### Keywords

GMRES, preallocate, vectors

### See Also

KSPGMRESSetRestart(), KSPGMRESSetOrthogonalization()

Level:intermediate
Location:src/ksp/ksp/impls/gmres/gmpre.c
Index of all KSP routines
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Index of all manual pages