[scikit-learn] How to test on PYTHON_ARCH=32 with mac?

[Matthew Brett]

On Wed, Jul 20, 2016 at 6:05 AM, lin yenchen <yenchenlin1994 at gmail.com> wrote:
> Hi all,
>
> currently the CI tests of my PR is failing only on appveyor when
> PYTHON_ARCH=32.
>
> Are there any ways to build a PYTHON_ARCH=32 version of scikit-learn on a
> mac,
> or the only solution is to get a windows computer?

If you install Python from Python.org installers, then the default
Python build flags, which should apply to scikit-learn too, specify to
build for both 32- and 64-bit (dual arch build).  I just tried:

pip install -e .

in the scikit-learn directory, for a Python.org Python.  That built
with the expected flags.  Then I checked skilearn imported OK in
32-bit mode with:

arch -i386 python
>>> import sklearn

Then I ran the sklearn tests with:

arch -i386 nosetests sklearn

I got a few failures.

I believe this `arch -i386`  only works as a prefix for Python.org
Python, but I'm happy to be corrected.

Cheers,

Matthew