Re: [Scikit-learn-general] Participation in GSoC 2013

2013-03-25 Thread Gael Varoquaux
A few notes: * Online and parallelisation are different things, both interesting and to keep in mind, but that should not be confused. * For non-negative matrix factorization, Julien Mairal's algorithm for online dictionary learning can also be used (see the JMLR paper). It needs a small mo

Re: [Scikit-learn-general] Any incremental classifier for sklearn

2013-03-25 Thread Mathieu Blondel
On Tue, Mar 26, 2013 at 1:41 AM, Olivier Grisel wrote: > I am also +1 a simple short term solution while still keeping longer > terms goal for > - proper multinomial penalized LR on one hand, It would still be nice to have it but if Paolo is correct, we should not expect it to produce well-calib

Re: [Scikit-learn-general] Website down

2013-03-25 Thread Gael Varoquaux
On Wed, Mar 06, 2013 at 01:26:42PM -0500, Ronnie Ghose wrote: > we can just put a javascript redirect / html redirect in the actual > source > code ...i'm pretty sure we can use some sort of engine or script to do this > for > us :/ That's very ugly, breaks search engines, and forces 2 HTTP

Re: [Scikit-learn-general] Any incremental classifier for sklearn

2013-03-25 Thread Olivier Grisel
2013/3/25 Paolo Losi : > My 2 cents ... > > The problem is that penalized (l1 o l2) single class Logistic Regression is > not > well calibrated to start with. > In other terms: the penalization param value that optimizes classification > accuracy is not > guaranteed to be the one that maximizes pro

Re: [Scikit-learn-general] Website down

2013-03-25 Thread Gael Varoquaux
On Wed, Mar 06, 2013 at 10:25:26AM -0500, Satrajit Ghosh wrote: > i don't know if this would be better a separate thread, but seemed related. is > there a reason why we don't just move the docs to github?  Lack of .htaccess that prevent us from using the rewriterules that we use to support multipl

Re: [Scikit-learn-general] Any incremental classifier for sklearn

2013-03-25 Thread Paolo Losi
My 2 cents ... The problem is that penalized (l1 o l2) single class Logistic Regression is not well calibrated to start with. In other terms: the penalization param value that optimizes classification accuracy is not guaranteed to be the one that maximizes probability estimation accuracy. Optimiz

Re: [Scikit-learn-general] Any incremental classifier for sklearn

2013-03-25 Thread Mathieu Blondel
On Mon, Mar 25, 2013 at 10:57 PM, Lars Buitinck wrote: > You mean the score rescaling at the end of section 2? What Zadrozny > and Elkan really seem to be recommended is isotonic regression... The question is how to deal with the *multiclass* case, which isotonic regression cannot handle directl

Re: [Scikit-learn-general] generation of a "random" confusion matrix

2013-03-25 Thread Gael Varoquaux
On Wed, Mar 20, 2013 at 09:33:06AM +0100, [email protected] wrote: > I need the random matrix to evaluate the predictiveness of a particular > model - this time, not in terms of a "domain of applicability" :) I would use the DummyClassifier. G --

Re: [Scikit-learn-general] Any incremental classifier for sklearn

2013-03-25 Thread Lars Buitinck
2013/3/25 Mathieu Blondel : >> I'm confused. Since when is that so? The other losses definitely support >> OvR multi-class. I would be quite surprised if 'log' does not. > > predict_proba currently raises an exception in the multiclass case: > https://github.com/scikit-learn/scikit-learn/blob/maste

Re: [Scikit-learn-general] Participation in GSoC 2013

2013-03-25 Thread Mathieu Blondel
Hello, Thanks for the interest in taking part to the GSOC! :) If they have time, I think that Gilles Louppe or Arnaud Joly would make good mentors since they are from University of Liège too. Gilles wrote his master thesis on recommender systems so he has good knowledge of matrix factorization pr

Re: [Scikit-learn-general] Any incremental classifier for sklearn

2013-03-25 Thread Mathieu Blondel
On Mon, Mar 25, 2013 at 9:19 PM, Andreas Mueller wrote: > I'm confused. Since when is that so? The other losses definitely support > OvR multi-class. I would be quite surprised if 'log' does not. predict_proba currently raises an exception in the multiclass case: https://github.com/scikit-learn/

Re: [Scikit-learn-general] Any incremental classifier for sklearn

2013-03-25 Thread Andreas Mueller
On 03/23/2013 06:37 PM, ShNaYkHs ShNaYkHs wrote: > Well, I need a classifier in that can support partial_fit() and can > give a probability for prediction proba_predict() (in case of > multi-class, not only binary). PassiveAggressiveClassifier and > Perceptron have no proba_predict() method, and