[R] randomForest question

2006-07-26 Thread Arne.Muller
Hello, I've a question regarding randomForest (from the package with same name). I've 16 featurs (nominative), 159 positive and 318 negative cases that I'd like to classify (binary classification). Using the tuning from the e1071 package it turns out that the best performance if reached when

Re: [R] randomForest question [Broadcast]

2006-07-26 Thread Liaw, Andy
When mtry is equal to total number of features, you just get regular bagging (in the R package -- Breiman Cutler's Fortran code samples variable with replacement, so you can't do bagging with that). There are cases when bagging will do better than random feature selection (i.e., RF), even in

[R] RandomForest question

2005-07-21 Thread Arne.Muller
Hello, I'm trying to find out the optimal number of splits (mtry parameter) for a randomForest classification. The classification is binary and there are 32 explanatory variables (mostly factors with each up to 4 levels but also some numeric variables) and 575 cases. I've seen that although

Re: [R] RandomForest question

2005-07-21 Thread Uwe Ligges
[EMAIL PROTECTED] wrote: Hello, I'm trying to find out the optimal number of splits (mtry parameter) for a randomForest classification. The classification is binary and there are 32 explanatory variables (mostly factors with each up to 4 levels but also some numeric variables) and 575

Re: [R] RandomForest question

2005-07-21 Thread Weiwei Shi
Hi, I found the following lines from Leo's randomForest, and I am not sure if it can be applied here but just tried to help: mtry0 = the number of variables to split on at each node. Default is the square root of mdim. ATTENTION! DO NOT USE THE DEFAULT VALUES OF MTRY0 IF YOU WANT TO OPTIMIZE THE

Re: [R] RandomForest question

2005-07-21 Thread Liaw, Andy
See the tuneRF() function in the package for an implementation of the strategy recommended by Breiman Cutler. BTW, randomForest is only for the R package. See Breiman's web page for notice on trademarks. Andy From: Weiwei Shi Hi, I found the following lines from Leo's randomForest,

Re: [R] RandomForest question

2005-07-21 Thread Liaw, Andy
From: [EMAIL PROTECTED] Hello, I'm trying to find out the optimal number of splits (mtry parameter) for a randomForest classification. The classification is binary and there are 32 explanatory variables (mostly factors with each up to 4 levels but also some numeric variables) and

Re: [R] RandomForest question

2005-07-21 Thread Liaw, Andy
From: Uwe Ligges [EMAIL PROTECTED] wrote: Hello, I'm trying to find out the optimal number of splits (mtry parameter) for a randomForest classification. The classification is binary and there are 32 explanatory variables (mostly factors with each up to 4 levels but also some