Hideaki Imamura

Thanks @nzw0301 to explain the rule. So, the rule is "The colormap is reversed when the `target` argument is not None or the objective function of the study is a...

I think the option 1 is good, since it is user-friendly. We should add a check about this.

I confirmed that the there is no error with the current master and `catboost==1.0.6` (latest one). We can just remove the line of `@pytest.mark.skip(reason="Temporally skip due to unknown CatBoost error.")`.

We have decided not to remove `n_jobs`. See https://github.com/optuna/optuna/pull/3173 for more details.

@contramundum53 Sorry. I'm busy now, so let me unassign me. Could you re-assign the reviewer?

The current status is as follows. - [ ] `optuna.samplers.RandomSampler` - [ ] `optuna.samplers.GridSampler` - [ ] `optuna.samplers.TPESampler` - [ ] `optuna.samplers.CmaEsSampler` - [ ] `optuna.integration.PyCmaSampler` - [ ] `optuna.integration.SkOptSampler`

Oh! Thanks, @c-bata. Fixed.

I think this is should be added into optuna-examples. Let me close this issue.

Ops. i misunderstood. It it good to add this tutorial into the document.

The constraint aware pareto front plot was introduced. The animation is the out of scope of Optuna V3. Let me remove the v3 label.