I was only able to get past this issue after upgrading to macOS Monterey. So seems there is no solution for Big Sur.
Reposting my response to above for more clarity
Platform: Mac mini (M1, 2020)
OS: Big Sur 11.6.2
Code is at https://github.com/almaudoh/lc0/tree/new-metal-backend-mpsgraph
You'd have to compile the executable from the source code. You need meson and ninja installed to compile.
Compile by running ./build.sh in the lc0 folder after cloning the repo above. You would also need to download a "weights" file that contains neural network weights. A sample can be downloaded here: https://storage.lczero.org/files/networks/b30e742bcfd905815e0e7dbd4e1bafb41ade748f85d006b8e28758f1a3107ae3
After compile, run /path/to/lc0/build/release/lc0 --weights=/path/to/weights/file --backend=metal where /path/to/weights/file refers to where you saved the downloaded neural network weights file.
Finally, in the lc0 command shell, run the command go infinite this starts to run the MPSGraph inference using the neural network stored in the weights file. This will throw the error mentioned above.
I realize this is a very involved process just to reproduce the error, but I hope it goes smoothly. Let me know if there are difficulties reproducing the error.
Thanks.
