# MatH2OpusLowRankUpdate
Perform a low-rank update of the form A = A + s * U * V^T 
## Synopsis
```
PetscErrorCode MatH2OpusLowRankUpdate(Mat A, Mat U, Mat V, PetscScalar s)
```

## Input Parameters

- ***A -*** the hierarchical `MATH2OPUS` matrix
- ***s -*** the scaling factor
- ***U -*** the dense low-rank update matrix
- ***V -*** (optional) the dense low-rank update matrix (if NULL, then V = U is assumed)



## Note
The U and V matrices must be in dense format




## See Also
 `MatCreate()`, `MATH2OPUS`, `MatCreateH2OpusFromMat()`, `MatCreateH2OpusFromKernel()`, `MatH2OpusCompress()`, `MatH2OpusOrthogonalize()`, `MATDENSE`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/h2opus/cuda/math2opus.cu.html#MatH2OpusLowRankUpdate">src/mat/impls/h2opus/cuda/math2opus.cu</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/mat/impls/h2opus/cuda/math2opus.cu)


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