CmdStanPy 1.0.0rc3

The second release candidate for CmdStanPy 1.0 is now up on pypi: cmdstanpy · PyPI

It will be up on conda-forge by tomorrow

pip install cmdstanpy==1.0.0rc2

This version plays nicely with the CmdStan 2.28 sampler’s num_chains feature, which lets you run multiple chains from within a single process, allowing for better parallelization, and lower memory overhead due to shared access to the input data across all chains.

In order to take advantage of this you must:

  • install latest CmdStan (2.28.1)
  • compile (or recompile) your models with argument cpp_options={'STAN_THREADS'='true'}.

Note: by default, CmdStanPy tries to avoid recompiling models when there’s an existing exe file that’s newer than the Stan file. There are two ways to force recompilation:

# force recompile on instantiation
mymodel = CmdStanModel(stan_file='mymodel.stan', cpp_options={'STAN_THREADS'='true'}, compile='force')

# call object's compile method
mymodel.compile(cpp_options={'STAN_THREADS'='true'}, force=True)

news flash: rc2 is up on conda-forge: Files ::

Hi all -

RC3 is being released now on PyPi. The only change is a fix to the install_cmdstan command, which is only necessary if you aren’t using the conda install.