[Numpy-discussion] Does numpy depend upon a Fortran library?

[Charles R Harris]

On Wed, Jan 30, 2019 at 6:32 PM Ralf Gommers <ralf.gommers at gmail.com> wrote:

>
>
> On Wed, Jan 30, 2019 at 5:19 PM Charles R Harris <
> charlesr.harris at gmail.com> wrote:
>
>>
>>
>> On Wed, Jan 30, 2019 at 5:28 PM Marc F Paterno <paterno at fnal.gov> wrote:
>>
>>> Hello,
>>>
>>> I have encountered a problem with a binary incompatibility between the
>>> Fortran runtime library installed with numpy when using 'pip install --user
>>> numpy', and that used by the rest of my program, which is built using
>>> gfortran from GCC 8.2.  The numpy installation uses libgfortran.5.dylib,
>>> and GCC 8.2 provides libgfortran.5.dylib.
>>>
>>> While investigating the source of this problem, I downloaded the numpy
>>> source
>>> (
>>> https://files.pythonhosted.org/packages/04/b6/d7faa70a3e3eac39f943cc6a6a64ce378259677de516bd899dd9eb8f9b32/numpy-1.16.0.zip
>>> ),
>>> and tried building it. The resulting libraries have no coupling to any
>>> Fortran library that I can find.  I can find no Fortran source code files
>>> in the numpy source,
>>> except in tests or documentation.
>>>
>>> I am working on a MacBook laptop, running macOS Mojave, and so am using
>>> the Accelerate framework to supply BLAS.
>>>
>>> I do not understand why the pip installation of numpy includes a Fortran
>>> runtime library. Can someone explain to me what I am missing?
>>>
>>>
>> That's interesting, it looks like the wheel includes four libraries:
>>
>> -rw-r--r--. 1 charris charris   273072 Jan  1  1980 libgcc_s.1.dylib
>> -rwxr-xr-x. 1 charris charris  1550456 Jan  1  1980 libgfortran.3.dylib
>> -rwxr-xr-x. 1 charris charris 63433364 Jan  1  1980
>> libopenblasp-r0.3.5.dev.dylib
>> -rwxr-xr-x. 1 charris charris   279932 Jan  1  1980 libquadmath.0.dylib
>>
>> I thought we only needed the openblas, but that in turn probably depends
>> on libgcc. But why we have the fortran library and quadmath escapes me.
>> Perhaps someone else knows.
>>
>
> I suspect it's a leftover from when we were using ATLAS, we did need a
> Fortran runtime library at some point. The cause will be somewhere in the
> numpy-wheel build scripts, there is a gfortran-install git submodule:
> https://github.com/MacPython/numpy-wheels
>

And fortran is probably why the quadmath is there. Hmm, if we fix it we
will need to test it...

Chuck

>
>
>>
>> Note that compiling from source is different and will generally use
>> different libraries. We don't use Accelerate because it is buggy, not
>> thread safe, and it appears Apple is not interested in doing anything about
>> that.
>>
>> Chuck
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