Re: [scikit-learn] GSoc, 2017 (proposal idea and intro) .reg

2017-03-13 Thread Shreyas Saligrama chandrakan
Hi, Is it possible for me to contribute a library to introduce SVM's with tree kernel (like current available one in svmlight) which is currently missing in scikit-learn? Best, Shreyas On 5 Mar 2017 11:03 a.m., "Andreas Mueller" wrote: > There was a PR here: > https://github.com/scikit-learn/s

Re: [scikit-learn] Label encoding for classifiers and soft targets

2017-03-13 Thread Javier López Peña
> On 13 Mar 2017, at 21:18, Andreas Mueller wrote: > > No, if all the samples are normalized and your aggregation function is sane > (like the mean), the output will also be normalised. You are completely right, I hadn’t checked this for random forests. Still, my purpose is to reduce model com

Re: [scikit-learn] Label encoding for classifiers and soft targets

2017-03-13 Thread Javier López Peña
> You could use a regression model with a logistic sigmoid in the output layer. By training a regression network with logistic activation the outputs do not add to 1. I just checked on a minimal example on the iris dataset. ___ scikit-learn mailing lis

Re: [scikit-learn] Label encoding for classifiers and soft targets

2017-03-13 Thread Andreas Mueller
On 03/13/2017 08:35 AM, Javier López Peña wrote: Training a regression tree would require sticking some kind of probability normaliser at the end to ensure proper probabilities, this might somehow hurt sharpness or calibration. No, if all the samples are normalized and your aggregation function

Re: [scikit-learn] Label encoding for classifiers and soft targets

2017-03-13 Thread Andreas Mueller
On 03/12/2017 03:11 PM, Javier López Peña wrote: The purpose is two-fold, on the one hand use the probabilities generated by a very complex model (e.g. a massive ensemble) to train a simpler one that achieves comparable performance at a fraction of the cost. Any universal classifier will do (

Re: [scikit-learn] Logistic regression with elastic net regularization

2017-03-13 Thread Sebastian Raschka
Hi, Stuart, I think the only way to do that right now would be through the SGD classifier, e.g., sklearn.linear_model.SGDClassifier(loss='log', penalty='elasticnet' …) Best, Sebastian > On Mar 13, 2017, at 12:57 PM, Stuart Reynolds > wrote: > > Is there an implementation of logistic regress

Re: [scikit-learn] Logistic regression with elastic net regularization

2017-03-13 Thread Stuart Reynolds
Perfect. Thanks -- will give it a go. On Mon, Mar 13, 2017 at 10:04 AM, Jacob Schreiber wrote: > Hi Stuart > > Take a look at this issue: https://github.com/scikit-learn/scikit-learn/ > issues/2968 > > On Mon, Mar 13, 2017 at 9:57 AM, Stuart Reynolds < > stu...@stuartreynolds.net> wrote: > >> Is

Re: [scikit-learn] Logistic regression with elastic net regularization

2017-03-13 Thread Guillaume Lemaitre
Recently, there are some issues/PRs tackling the topic: https://github.com/scikit-learn/scikit-learn/issues/8288 https://github.com/scikit-learn/scikit-learn/issues/8446 ___ scikit-learn mailing list scikit-learn@python.org https://mail.python.org/mailm

Re: [scikit-learn] Differences between scikit-learn and Spark.ml for regression toy problem

2017-03-13 Thread Stuart Reynolds
Both libraries are heavily parameterized. You should check what the defaults are for both. Some ideas: - What regularization is being used. L1/L2? - Does the regularization parameter have the same interpretation? 1/C = lambda? Some libraries use C. Some use lambda. - Also, some libraries regula

Re: [scikit-learn] Logistic regression with elastic net regularization

2017-03-13 Thread Jacob Schreiber
Hi Stuart Take a look at this issue: https://github.com/scikit-learn/scikit-learn/issues/2968 On Mon, Mar 13, 2017 at 9:57 AM, Stuart Reynolds wrote: > Is there an implementation of logistic regression with elastic net > regularization in scikit? > (or pointers on implementing this - its seems

[scikit-learn] Logistic regression with elastic net regularization

2017-03-13 Thread Stuart Reynolds
Is there an implementation of logistic regression with elastic net regularization in scikit? (or pointers on implementing this - its seems non-convex and so you might expect poor behavior with some optimizers) - Stuart ___ scikit-learn mailing list scik

Re: [scikit-learn] Label encoding for classifiers and soft targets

2017-03-13 Thread Javier López Peña
Hi Giles, thanks for the suggestion! Training a regression tree would require sticking some kind of probability normaliser at the end to ensure proper probabilities, this might somehow hurt sharpness or calibration. Unfortunately, one of the things I am trying to do with this is moving away fr

Re: [scikit-learn] Label encoding for classifiers and soft targets

2017-03-13 Thread Gilles Louppe
Hi Javier, In the particular case of tree-based models, you case use the soft labels to create a multi-output regression problem, which would yield an equivalent classifier (one can show that reduction of variance and the gini index would yield the same trees). So basically, reg = RandomForestRe