Within-chain parallelisation on M1 Mac for CmdStanr

Developers
1

Hi, I am wondering if Stan currently (or will in future) supports within-chain parallelisation for arm64 Macs? I am trying to run an example model (from dschrage / rcovreg · GitLab) and constantly get thrown this error:

dyld[25746]: Library not loaded: @rpath/libtbb.dylib
Reason: tried: ‘~/.cmdstanr/cmdstan-2.28.2/stan/lib/stan_math/lib/tbb/libtbb.dylib’ (mach-o file, but is an incompatible architecture (have ‘arm64’, need ‘x86_64’)),

The error goes away after removing “cpp_options = list(stan_threads = TRUE)” from the model.

R version 4.1.2 (2021-11-01)
Platform: aarch64-apple-darwin20 (64-bit)
Running under: macOS Monterey 12.2

2

This part seems to suggest that this is installation is a bit weird. As it is looking for x86, which is the non-Mac version.

Within-chain parallelization should work on M1 Mac with CmdStanR, there are quite a few reports of it working pretty well actually.

3

Thanks! Any idea how to resolve this? I’ve rebuilt CmdStan and reinstalled but to no avail. Seems like the issue is with the tbb library.

4

Update: Apologies, managed to run within-chain parallelisation with the brms example (Running brms models with within-chain parallelization). Issue could have been with the way the example from before was coded.

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