Expressing a prior thru a Potential

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Can you try with a higher number of samples and show the traces? I’m interested to see if there’s obvious auto-correlation or if the model is getting stuck in a mode. Junpenglao has mentioned that the 25% is quite aggressive compared to stan:

The number of effective samples is smaller than 25% for some parameters

The low number of effective samples is usually an indication of strong autocorrelation in the chain. You can plot the trace autocorrelation or look at the trace plot directly. Usually, this could be improved by using more efficient sampler like NUTS. However, in this case since you are mixing discrete random variable with continuous variables, sampling is likely going to be a bit difficult. You can find more information about effective sample size from Gelman et al’s book Bayesian Data Analysi…