I am picking up pymc again after a long hiatus. I am using pymc v5.1.1. The following warning function which can be found in `stats/convergence.py`

seems to generate a lot of warnings for a simple test model.

At this point I don’t really understand the concept of treedepth so I don’t have a clue about what it is supposed to check. Hopefully my questions are nevertheless relevant.

```
def warn_treedepth(idata: arviz.InferenceData) -> List[SamplerWarning]:
...
for c in treedepth.chain:
if sum(treedepth.sel(chain=c)) / treedepth.sizes["draw"] > 0.05:
warnings.append(...)
return warnings
```

My questions:

- It seems like
`sum(... ) / ...`

is a little slow to execute. Probably because it uses the pure python sum instead of`.sum`

. I tried to replace the fraction by`float(treedepth.sel(chain=c).mean())`

and it gives the same number for my case. - The message it generates will tell you that the maximum treedepth has been reached. But the actual check verifies that the
**MEAN**treedepth is greater than 0.05. So which one is supposed to be correct? - Could it be that is is supposed to be > 20 or so? Seems to me that the mean treedepth will always be > 1 so warning when it is > 0.05 makes little sense to me.