I’m running brms version 2.14.4. With no within-chain parallelization, the model seems fine. However, with within-chain parallelization:
brm(y ~ grp+offset(log(X))+(1|cell), data=dat, family = negbinomial(), chains = 4, iter=1000, backend = “cmdstanr”, threads = threading(6))
it throws out the following error:
Running MCMC with 4 chains, at most 24 in parallel, with 6 thread(s) per chain…
Warning: Chain 1 finished unexpectedly!
Warning: Chain 2 finished unexpectedly!
Warning: Chain 3 finished unexpectedly!
Warning: Chain 4 finished unexpectedly!
Warning: Use read_cmdstan_csv() to read the results of the failed chains.
Error in rstan::read_stan_csv(out$output_files()) :
csvfiles does not contain any CSV file name
Calls: brm … eval2 -> eval -> eval -> .fun -> .fit_model ->
In addition: Warning messages:
1: All chains finished unexpectedly!
2: No chains finished successfully. Unable to retrieve the fit.
Let me know if you need more information. Thanks!