[Scikit-learn-general] 'shrinkage'/'learning rate' in AdaBoost question

2014-02-09 Thread Thomas Dent
Hi - is there an explicit mathematical statement somewhere of what the 'learning_rate' parameter does in AdaBoost? I can't actually find a formula that makes sense and shows what the difference is when varying the parameter. Or failing that, where in the code does it get applied? Thanks, Th

Re: [Scikit-learn-general] Custom function in decision-tree based classifiers

2013-11-17 Thread Thomas Dent
Hi Gilles - thanks for the reply. I think changing the relative class weights does more or less what we want, which is to optimize the classification at very low false alarm probability. Another question on the DecisionTreeClassifier, does the argument splitter='best' actually do anything?

[Scikit-learn-general] Custom function in decision-tree based classifiers

2013-11-07 Thread Thomas Dent
Hi, the only current options for deciding on feature splits in trees / forests are 'entropy' and 'gini', two questions on this: - is anyone planning on implementing others? - how feasible would it be to have the option of passing custom function to the tree or forest to use in splitting? W

Re: [Scikit-learn-general] what is 'distance' in the nearest-neighbors module when p=2? p>2?

2013-01-22 Thread Thomas Dent
-- - Institute for Gravitational Physics (Albert Einstein Institute) Callinstr. 38 D-30167 Hannover, Germany On Jan 21, 2013, at 11:41 PM, Lars Buitinck wrote: > 2013/1/21 Jake Vanderplas : >> On 01/21/2013 01:13 PM, Lars Buitinck wrote: >>> 2013/1/21 Thomas Dent : >>>> my ques

Re: [Scikit-learn-general] what is 'distance' in the nearest-neighbors module when p=2? p>2?

2013-01-21 Thread Thomas Dent
38 D-30167 Hannover, Germany On Jan 21, 2013, at 8:57 PM, Willi Richert wrote: > Yes, it is the parameter p in the Minkowski distance: > http://en.wikipedia.org/wiki/Minkowski_distance. > > I think the master branch should have this information in the docs. > > > 201

[Scikit-learn-general] what is 'distance' in the nearest-neighbors module when p=2? p>2?

2013-01-21 Thread Thomas Dent
Hi all, I just started using sklearn nearest-neighbors for classification & would like to apply my own distance weighting function. To do this I need to know exactly what the 'distance' that is fed to the function represents. (Current documentation doesn't give me an immediate answer.) Fo