We are planning to drop 32-bit compatibility from the numpy macOS
wheels. This email is to ask for feedback.
macOS has tooling to allow distribution of binaries that have objects
for more than one architecture. These are called "fat" binaries, and
they were useful when Macs could be PPC, 32-bit or 64-bit intel. Now
of course, they are effectively all 64-bit Intel.
Amusingly enough, you can use the "lipo" command to operate on fat
binaries. For example, system Python (at /usr/bin/python) is a fat
binary, containing objects for 32 and 64-bit.
$ lipo -info /usr/bin/python
Architectures in the fat file: /usr/bin/python are: i386 x86_64
It is possible to run Python in 32-bit mode with:
$ arch -i386 /usr/bin/python
Up until the last release of numpy, we have build fat (32 and 64 bit)
binaries for numpy, so, if you do run Python in 32-bit mode, you can
still import and use numpy. In the last release, I accidentally
broke the 32-bit part of the build - see
We could fix this, but we suspect that there are very few people still
using 32-bit on macOS. If you do use it - please let us know, and
we'll consider the options.