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tags: [meeting, notes]
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*Attendees*: Isaac Virshup (@ivirshup), Jim Kitchen (@jim22k), Simon Cross (@hodgestar), Eric Gigure (@Ericgig)

# Sparse interest meetup

* Jim – at anaconda, working on python-graphblas
* Eric– Sherbrooke QuTiP
* Rewrote sparse operations because scipy was too slow
* Simon Cross – QuTiP RIKEN
* Implemented cython based sparse arrays within qutip
* Problems with scipy sparse:
* Sparse addition doing uneccesary copies
* Inititalization and complex types
* There are lots of checks making things slow
* Downcasting indices/ indptr
* Linear algebra and ODE use cases
* Jim graph blas/ suite sparse
* "sparse values" that aren't zero
* suite sparse
* Masked arrays
* COO, CSR, and
* MLIR graph blas
* python-graphblas
* Not Jit
* Matrices must be 64 bit

* On disk formats (degree of specialization)
* Out of core needs?
* Not doing a ton of this yet, but broad interest
* Dask Graph blas from Eric Welch

### Links to projects

* [AnnData](https://anndata.readthedocs.io/en/latest/) (ivirshup)
* [qutip](https://qutip.org)
* [python-graphblas](https://python-graphblas.readthedocs.io/en/latest/)

## Follow up

* We will follow up on sparse on the discourse/
* TODO: Ask scientific python about where to discuss