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

[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

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

2013-07-12 Thread Sergey Feldman
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, Sergey Feldman sergeyfeld

[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