API: Add kwargs to sparse.einsum

[mtsokol]

Related issue: #589

Hi @hameerabbasi,

I think the original error was caused due to the fact that np.einsum has kwargs which is missing in sparse.einsum. There is no Array API standard definition for einsum function so maybe we can just add **kwargs to sparse.einsum to make it compatible.

If there are plans for refactoring sparse.einsum in the future, then there will be an opportunity to introduce dtype parameter.

[codecov]

Codecov Report

Merging #620 (4850f56) into master (925112f) will increase coverage by 0.00%.
The diff coverage is 100.00%.

Additional details and impacted files

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+ Hits         3254     3256    +2     
  Misses        347      347           

[hameerabbasi]

While the optimize kwarg certainly isn't urgent as it doesn't change the result, I'd consider the dtype kwarg to be sufficiently important to coerce all the inputs to it before an operation.

[mtsokol]

While the optimize kwarg certainly isn't urgent as it doesn't change the result, I'd consider the dtype kwarg to be sufficiently important to coerce all the inputs to it before an operation.

Sure! I added dtype parameter and input operators are mapped to it with astype.

[hameerabbasi]

Thanks, @mtsokol!