# MatLMVMSymBroydenSetScaleType
Sets the scale type for symmetric Broyden-type updates. 
## Synopsis
```
#include "petscksp.h" 
PetscErrorCode MatLMVMSymBroydenSetScaleType(Mat B, MatLMVMSymBroydenScaleType stype)
```

## Input Parameters

- ***snes -*** the iterative context
- ***rtype -*** restart type



## Options Database Key

- ***-mat_lmvm_scale_type <none,scalar,diagonal> -*** set the scaling type





## MatLMVMSymBrdnScaleTypes

- ***MAT_LMVM_SYMBROYDEN_SCALE_NONE -*** initial Hessian is the identity matrix
- ***MAT_LMVM_SYMBROYDEN_SCALE_SCALAR -*** use the Shanno scalar as the initial Hessian
- ***MAT_LMVM_SYMBROYDEN_SCALE_DIAGONAL -*** use a diagonalized BFGS update as the initial Hessian



## See Also
 [](chapter_ksp), `MATLMVMSYMBROYDEN`, `MatCreateLMVMSymBroyden()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/utils/lmvm/symbrdn/symbrdn.c.html#MatLMVMSymBroydenSetScaleType">src/ksp/ksp/utils/lmvm/symbrdn/symbrdn.c</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/ksp/ksp/utils/lmvm/symbrdn/symbrdn.c)


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