Example of tar_stan_compile + tar_stan_mcmc?

[potash]

Prework

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Question

I am fitting the same model on a bunch of datasets using static branching (tar_map()). I think if I use tar_stan_mcmc() by itself, the first time the pipeline is run, it may try to compile the model once for each branch. Instead, I would like a single root step that does the compilation.

So I am trying to use tar_stan_compile(). But I cannot figure out how to feed the output into tar_stan_mcmc(). Can you provide an example for this or show a better way to achieve the result? Thanks!

[wlandau]

@potash, I think tar_stan_mcmc_rep_summary() (with the summaries argument) or tar_stan_mcmc_rep_draws() (with the transform argument) would be a more convenient fit. The compile argument allows you to control whether the model is compiled once beforehand or each time a batch runs. There is a good chance https://docs.ropensci.org/stantargets/articles/simulation.html has what you need.

[potash]

Thanks @wlandau to be honest i just ended up using cmdstanr directly (using a custom tar_format() that calls cmdstanr's save_object()) and for me that is easier to fit into the static and dynamic branching examples I find in targets.