Hi, I am new in the bayesian world. I am doing my thesis about a mathematical model that describes the epidemic of Sars-Cov-2 in Lombardaia, a region in Italy.

I would like to fit the new recovered (= hospitalized) for day.

My fitting says:

Warning messages:

1: In system(paste(CXX, ARGS), ignore.stdout = TRUE, ignore.stderr = TRUE) :

β-Eβ not found

2: There were 5999 divergent transitions after warmup. See

http://mc-stan.org/misc/warnings.html#divergent-transitions-after-warmup

to find out why this is a problem and how to eliminate them.

3: Examine the pairs() plot to diagnose sampling problems

4: The largest R-hat is NA, indicating chains have not mixed.

Running the chains for more iterations may help. See

http://mc-stan.org/misc/warnings.html#r-hat

5: Bulk Effective Samples Size (ESS) is too low, indicating posterior means and medians may be unreliable.

Running the chains for more iterations may help. See

http://mc-stan.org/misc/warnings.html#bulk-ess

6: Tail Effective Samples Size (ESS) is too low, indicating posterior variances and tail quantiles may be unreliable.

Running the chains for more iterations may help. See

http://mc-stan.org/misc/warnings.html#tail-ess

If you are interested the results, in png format, are in this link:

I donβt know how can I improve my fitting, do you have any suggestions? Thank you.

I share my code: