Quentin Soubeyran

`plot_evaluations` doesn't plot on a single `Axes` object, as each plot in the final result is an independent `Axes`. I don't see how to pass an `ax: Axes` parameter in...

Oh I'll look into it then !

@Abdelgha-4 I am working on #1081 to add this argument. I modified `plot_objective` for now, which seems to work properly. Does that cover your feature request ? Tested using: ```python...

`plot_evaluations` now also has the `ax` arguments (as well as some others that used to be hard-coded).

I believe this is intended: specifying spaces using list and tuple is a short-hand, and scikit-optimize is trying to guess what you mean. If you pass `int`, it believe you...

The other bugs mentioned are indeed bugs. I also think list should always lead to `Categorical` object. What do you think @kernc @glouppe ? See #1067

@Abdelgha-4 generally speaking, when your classifier doesn't vary, you should define it in the pipeline instead of using `DummyClassifier`and leave it out of the hyper-parameter space. I'll look into the...

I found the problem, it was the same as before: a wrong indexing causing problems when some dimensions are skipped (`iscat[j]` instead of `iscat[index]`)

@kernc @glouppe This is ready for review

@kernc I made tuples fall back to `Categorical` dimensions, with a warning if the tuple seems to be wrong. Is this better ?