# MatH2OpusCompress
Compress a hierarchical matrix. 
## Synopsis
```
PetscErrorCode MatH2OpusCompress(Mat A, PetscReal tol)
```

## Input Parameters

- ***A -*** the matrix
- ***tol -*** the absolute truncation threshold





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

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/h2opus/cuda/math2opus.cu.html#MatH2OpusCompress">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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