Re: [Scikit-learn-general] sample_weight and features in a single tree

2013-08-28 Thread Sergey Feldman
Huh, cool I didn't know about balance_weights before. I'm also having a hard time finding documentation on it besides: "DEPRECATED: balance_weights is an internal function and will be removed in 0.16" What will it be replaced by in 0.16? Thanks, sf On Wed, Aug 28, 2013 at 4:10 AM, Gilles Loup

Re: [Scikit-learn-general] Trees with unbalanced classes

2013-07-12 Thread Sergey Feldman
mple to see the sample_weights format. > http://scikit-learn.org/stable/auto_examples/svm/plot_weighted_samples.html > > You can provide different weights to different classes (for e.g., > inversely proportional to the number of samples). > > -Manish > > On Jul 12, 2013, at 4:40 PM, S

[Scikit-learn-general] Trees with unbalanced classes

2013-07-12 Thread Sergey Feldman
I'm dealing with a 50-class classification problem with extremely unbalanced classes. The smallest class has about 1000 samples and the largest has 500,000. The random forest I've trained is being heavily skewed towards the big classes. Is there a good way to deal with this kind of problem in sk

Re: [Scikit-learn-general] Adding regularization to QDA (and another change)

2013-07-07 Thread Sergey Feldman
Whoops, I should have checked that a bit better =) The regularization needs to be added to "S2" and not "S". On Sun, Jul 7, 2013 at 4:55 PM, Sergey Feldman wrote: > Howdy, > > I noticed that the sklearn library's QDA doesn't have any regularization. I

[Scikit-learn-general] Adding regularization to QDA (and another change)

2013-07-07 Thread Sergey Feldman
Howdy, I noticed that the sklearn library's QDA doesn't have any regularization. In my experience, a little convariance regularization can mean the difference between total failure due to numerical issues and surprisingly high classification accuracy. Adding something basic would be as simple as