While trying some experiment about beta distributions I found thid weird behaviour…
This code works :
with pm.Model() as model: r0 = pm.Beta('r0',alpha=1+60,beta=1+60) trace = pm.sample(chains=1) _ = pm.traceplot(trace)
But this one, just changing the alpha & beta params from 60 to 70 :
with pm.Model() as model: r0 = pm.Beta('r0',alpha=1+70,beta=1+70) trace = pm.sample(chains=1) _ = pm.traceplot(trace)
fails with a : “ValueError: Bad initial energy: nan. The model might be misspecified.”
I don’t understand why !? And this is even more strange :
r0 = pm.Beta('r0',alpha=1+999,beta=1+999)
Why certain specific parameter values range seem to have problem ?
Any help appreciated.