How come pm.sample() doesn't tell you when you pass in a bad argument?

Development
1

I got confused for a while as to why I was getting so many divergences before I realised it was because I’d typed in the target_accept argument wrong into pm.sample(). I had

trace = pm.sample(4000, tune=1000, target_accept=.95)

Instead of

trace = pm.sample(4000, tune=1000, nuts_kwargs=dict(target_accept=.95))

Easy mistake to make, right? The bad input failed silently and the target_accept used the default of 0.8 instead of what I wanted. I feel like it should throw an exception (or at least a warning) when you give it a bad named argument. I found that you can even feed it nonsense like

trace = pm.sample(4000,  tune=1000, abloogiwoogiwoo="the quick brown fox jumps over the lazy dog")

and it will happily go on sampling without complaint. What’s the reason behind this behaviour?

2

Yep, we definitively need some improvement here, see related Github issue: https://github.com/pymc-devs/pymc3/issues/3226

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