Libtorch integration for ARM macs

[andleb]

Originally posted by @andleb in #983 (comment)

First, apologies for any inconvenience, but I reckoned I'd get more eyeballs on this if opened an issue instead of a comment on a closed issue.

The crux of the matter is that libtorch binaries for ARM Macs are outside the range officially supported by PLUMED, so I'd love to hear some feedback whether there's any way around this right now.

Details:

Running ./configure using the old 1.13.1 C++-abi library fails (I know for sure that the test code in configure.ac does not compile). However, using the correct libtorch-macos-arm64-2.*.zip, for which the test example compiles, also fails to configure; my guess would be since versions above 2.0 are not supported (and older ones are not available here ).

I have installed libtorch as instructed (and can compile & link the test examples from torch separately), as well as tried all the permutations of the ./configure options above. Is my reading correct and are those with ARM Macs stuck for now?

[Luthaf]

This is a bit strange, I am working on the metatensor package, which has similar goals as the PYTORCH one, and my code uses the exact same part of the configure script to find and link to libtorch. Everything works fine for me on a M1 macbook.

Maybe you can try the instructions for libtorch here and skip the bits that are metatensor-specific?