[scikit-learn] How to not recalculate transformer in a Pipeline?

[Andreas Mueller]

On 11/28/2016 10:46 AM, Gael Varoquaux wrote:
> I use joblib.Memory for this purpose. I think that including a
> meta-transformer that embeds a joblib.Memory would be a good addition to
> scikit-learn.
To cache the result of "transform"? You still have to call "fit" 
multiple times, right?
Or would you cache the return of "fit" as well as "transform"?
Caching "fit" with joblib seems non-trivial.