On Sat, Oct 29, 2011 at 12:50 AM, Gael Varoquaux <[email protected]> wrote:
> Could you give an example of what you have in mind? I am probably just > revealing my lack of knowledge here. I already gave 2 examples: early stopping (tuning the number of iterations) and regularization parameter tuning (e.g. using Bottou's trick for SGD). In general, any kind of hyperparameter tuning, which can be broken do into a part which is common to each split and a part which is specific to each split, is inefficient with a generic GridSearchCV, as GridSearchCV recomputes the common part again and again (of course joblib may help). I think that Olivier's idea of having percentage_val in the constructor is reasonable and it doesn't change the fit API. Regarding GridSearchValidation. My feeling here is that just to avoid adding a new helper class or function, you're bending the GridSearchCV API in a way which is really user unfriendly. At first glance, I'm not really convinced by your tricks: they seem hard to read and to require fairly advance knowledge of what's going on in GridSearchCV. In constrast, Olivier's IPython snippet speaks for itself. Digression. In my experience, in machine learning, generic code can be much slower than specific code: you just cannot beat an algorithm which takes advantage of a problem's peculiarities. For example, a generic one-vs-rest implementation is probably near optimal if the base classifier is a linear one but it will be really sub-optimal if the base classifier is a kernel one. In the kernel case, I could design my outer and inner loops to maximize kernel cache reuse across the classes. I should really go back to work, otherwise there's no point staying late in the lab on a friday night :) Cheers, Mathieu ------------------------------------------------------------------------------ The demand for IT networking professionals continues to grow, and the demand for specialized networking skills is growing even more rapidly. Take a complimentary Learning@Cisco Self-Assessment and learn about Cisco certifications, training, and career opportunities. http://p.sf.net/sfu/cisco-dev2dev _______________________________________________ Scikit-learn-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/scikit-learn-general
