# MatLMVMSetJ0Diag
Allows the user to define a vector V such that J0 = diag(V). 
## Synopsis
```
#include "petscksp.h" 
PetscErrorCode MatLMVMSetJ0Diag(Mat B, Vec V)
```

## Input Parameters

- ***B -*** An LMVM-type matrix
- ***V -*** Vector that defines the diagonal of the initial Jacobian





## See Also
 [](chapter_ksp), [LMVM Matrices](sec_matlmvm), `MATLMVM`, `MatLMVMSetScale()`, `MatLMVMSetJ0()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/utils/lmvm/lmvmutils.c.html#MatLMVMSetJ0Diag">src/ksp/ksp/utils/lmvm/lmvmutils.c</A>


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


[Index of all KSP routines](index.md)  
[Table of Contents for all manual pages](/docs/manualpages/index.md)  
[Index of all manual pages](/docs/manualpages/singleindex.md)  
