Attempting to sample from any model on a cluster fails with: Native call to processx_exec failed

[JasonPekos]

I'm attempting to run a targets workflow on the ComputeCanada Graham cluster, which has the option to use either a SLURM scheduler or interactive sessions. Any attempt to call a stantargets target that samples from a model will fail with the following error:

Error:
! Error running targets::tar_make_clustermq()
  Error messages: targets::tar_meta(fields = error, complete_only = TRUE)
  Debugging guide: https://books.ropensci.org/targets/debugging.html
  How to ask for help: https://books.ropensci.org/targets/help.html
  Last error: ! ! Native call to `processx_exec` failed
Caused by error in `chain_call(c_processx_exec, command, c(command, args), pty, pty_options, …`:
! cannot start processx process '[path to stan model]' (system error 13, Permission denied) @unix/processx.c:611 (processx_exec)

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I can do the following:

1. Compile and sample from the Bernoulli example / test case in the cmdstanr intro vignette.
2. Run other targets which don't involve sampling from a model.

I've tried using tar_make_clustermq(), tar_make_future(), and just tar_make(), and it always fails on the MCMC targets with the above error.

I'm sure there's something obvious I'm missing — I have very little experience with HPC — but I couldn't find anything on google, so I thought it'd be worth it to ask here.

[JasonPekos]

Ok, I think:

Compile and sample from the Bernoulli example / test case in the cmdstanr intro vignette.

is wrong — the Bernoulli example is already compiled with cmdstan install(?), so I never actually compiled anything. Trying to actually compile models, e.g. with mod <- cmdstan_model(file) fails with the same error.

So this is a cmdstanr / cluster / processx issue, unrelated to stantargets. If I find a solution elsewhere, I'll link it here for people who might run into something similar.

(PS: I'm still not sure what the actual problem is, so if anyone knows, I'd still love to hear it!)

[JasonPekos]

Ok, it was a dumb mistake on my part: when I copied my files over from my local computer, I accidentally copied over stan model executables which were compiled for a different architecture. Deleting all executables and recompiling solved my problem. Stan discourse link here.