Add information about pybind11 and NumPy C-API to the guide

[tdhock]

Hi! I was wondering if there are plans to discuss the NumPy C API? https://numpy.org/doc/stable/reference/c-api/index.html
If not, can you please add link to a recommended external resource like the C API doc page?
Thanks!

[willingc]

@tdhock Hi. Sorry for the delay in getting to this issue. Would you please share where you think mentioning the NumPy C API would be helpful to mention? Thanks!

[agriyakhetarpal]

If it is about the use of the NumPy C-API from a packaging perspective, then I was able to find these resources from a quick search:

• https://github.com/johnnylee/python-numpy-c-extension-examples, but this is 12 years old and likely very out of date
• this looks like a maintained one: https://github.com/ssciwr/pybind11-numpy-example, on PyPI as https://pypi.org/project/pybind11-numpy-example
• the NumPy C-API docs are here, of course: https://numpy.org/doc/stable/reference/c-api/index.html
• continuation: https://numpy.org/doc/stable/user/c-info.how-to-extend.html
• maybe https://github.com/scikit-build/scikit-build-sample-projects/ should include a NumPy C-API extension example?

[willingc]

Thanks @agriyakhetarpal. That is very helpful.

[tdhock]

I would recommend discussing pybind11

[lwasser]

Hi friends. I am catching up here! Would it be useful to add some of these resource links to our guide? if so i can add this to the help-wanted board for when we sprint? And does Henry's guide over in scientific python cover this topic as we could link there too.

[lwasser]

@all-contributors please add @tdhock for docs

[allcontributors]

@lwasser

I've put up a pull request to add @tdhock! 🎉

[tdhock]

I taught a class about this last semester and I used the docs https://pybind11.readthedocs.io/en/stable/advanced/pycpp/numpy.html#vectorizing-functions as a reference — it has an easy to understand example about how to convert py::array_t<double> to double* that maybe could be adapted / simplified / better explained in the python package guide?