Joel Nothman

We could give up on the `isinstance` criterion and require that users do not use `isinstance` with estimator types on the RHS except in testing and similar. Uses of isinstance...

I've not checked whether any of these are reasonable use contexts for frozen models.

I agree that we've got too many tricky criteria here, and it's not going to work with all of them maintained. On 16 February 2017 at 20:57, Gael Varoquaux wrote:...

> Every estimator needs to be coded to check in fit whether to fit. I don't think that's reasonable. More simply it can be the responsibility of meta-estimators. Each could...

And I'm leaning towards that approach. I don't think we should modify `BaseEstimator`, just `clone` and meta-estimators and a new `freeze` which sets the flag. Is `trainable` appropriate, or does...

Since it needs to be handled in each meta-estimator, it is open to buggy implementations (remembering to check for it in one place and not another), so we need to...

In discussion earlier, @GaelVaroquaux and I came to some agreement that a simple design goes as follows (more or less what I said in February): * user may set `estimator.frozen...

Although #8374 may remain conceptually simpler for users (because it should work in all contexts), but a little more magical. It overwrites the fit method in frozen estimators with a...

Can you describe your use case, so that we can evaluate whether this is indeed the best solution, and thus have more support for its inclusion?

One variant we have considered is where the meta-estimator can mark some of its parameters as not to be cloned. Would that work?