[Numpy-discussion] State-of-the-art to use a C/C++ library from Python

[Nathaniel Smith]

On Fri, Sep 2, 2016 at 1:16 AM, Peter Creasey
<p.e.creasey.00 at googlemail.com> wrote:
>> Date: Wed, 31 Aug 2016 13:28:21 +0200
>> From: Michael Bieri <mibieri at gmail.com>
>>
>> I'm not quite sure which approach is state-of-the-art as of 2016. How would
>> you do it if you had to make a C/C++ library available in Python right now?
>>
>> In my case, I have a C library with some scientific functions on matrices
>> and vectors. You will typically call a few functions to configure the
>> computation, then hand over some pointers to existing buffers containing
>> vector data, then start the computation, and finally read back the data.
>> The library also can use MPI to parallelize.
>>
>
> Depending on how minimal and universal you want to keep things, I use
> the ctypes approach quite often, i.e. treat your numpy inputs an
> outputs as arrays of doubles etc using the ndpointer(...) syntax. I
> find it works well if you have a small number of well-defined
> functions (not too many options) which are numerically very heavy.
> With this approach I usually wrap each method in python to check the
> inputs for contiguity, pass in the sizes etc. and allocate the numpy
> array for the result.

FWIW, the broader Python community seems to have largely deprecated
ctypes in favor of cffi. Unfortunately I don't know if anyone has
written helpers like numpy.ctypeslib for cffi...

-n

-- 
Nathaniel J. Smith -- https://vorpus.org