Displaying 20 results from an estimated 20000 matches similar to: "Half Million features Selection (Random Forest)"
2009 Apr 28
1
Problem with Random Forest predict
I am trying to run a partialPlot with Random Forest (as I have done many times before).
First I run my forest... Cell is a 6 level factor that is the dependent variable - all other variables are predictors, most of these are factors as well.
predCell<-randomForest(x=tempdata[-match("Cell",names(tempdata))],y=tempdata$Cell,importance=T)
Then I try my partial plot to look at the
2007 Apr 23
6
Random Forest
Hi,
I am trying to print out my confusion matrix after having created my random
forest.
I have put in this command:
fit<-randomForest(MMS_ENABLED_HANDSET~.,data=dat,ntree=500,mtry=14,
na.action=na.omit,confusion=TRUE)
but I can't get it to give me the confusion matrix, anyone know how this
works?
Thansk!
Ruben
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2011 Mar 07
2
use "caret" to rank predictors by random forest model
Hi,
I'm using package "caret" to rank predictors using random forest model and draw predictors importance plot. I used below commands:
rf.fit<-randomForest(x,y,ntree=500,importance=TRUE)
## "x" is matrix whose columns are predictors, "y" is a binary resonse vector
## Then I got the ranked predictors by ranking
2012 Dec 03
2
Different results from random.Forest with test option and using predict function
Hello R Gurus,
I am perplexed by the different results I obtained when I ran code like
this:
set.seed(100)
test1<-randomForest(BinaryY~., data=Xvars, trees=51, mtry=5, seed=200)
predict(test1, newdata=cbind(NewBinaryY, NewXs), type="response")
and this code:
set.seed(100)
test2<-randomForest(BinaryY~., data=Xvars, trees=51, mtry=5, seed=200,
xtest=NewXs, ytest=NewBinarY)
The
2012 Apr 10
1
Help predicting random forest-like data
Hi,
I have been using some code for multivariate random forests. The output
from this code is a list object with all the same values as from
randomForest, but the model object is, of course, not of the class
randomForest. So, I was hoping to modify the code for predict.randomForest
to work for predicting the multivariate model to new data. This is my
first attempt at modifying code from a
2011 Oct 10
1
pmml for random forest & rules
Hi,
I am having some trouble using R 2.13.1 for generating a pmml object
of of class "c('randomForest.formula', 'randomForest')"
I see that these methods are available:
> methods(pmml)
[1] pmml.coxph* pmml.hclust* pmml.itemsets* pmml.kmeans*
pmml.ksvm* pmml.lm* pmml.multinom* pmml.nnet*
pmml.rpart*
[10] pmml.rsf* pmml.rules* pmml.survreg*
2013 Jan 15
1
Random Forest Error for Factor to Character column
Hi,
Can someone please offer me some guidance?
I imported some data. One of the columns called "JOBTITLE" when imported was imported as a factor column with 416 levels.
I subset the data in such a way that only 4 levels have data in "JOBTITLE" and tried running randomForest but it complained about "JOBTITLE" having more than 32 categories. I know that is the limit
2013 Mar 24
1
Random Forest, Giving More Importance to Some Data
Dear All,
I am using randomForest to predict the final selling price of some items.
As it often happens, I have a lot of (noisy) historical data, but the
question is not so much about data cleaning.
The dataset for which I need to carry out some predictions are fairly
recent sales or even some sales that will took place in the near future.
As a consequence, historical data should be somehow
2011 Sep 13
1
class weights with Random Forest
Hi All,
I am looking for a reference that explains how the randomForest function in
the randomForest package uses the classwt parameter. Here:
http://tolstoy.newcastle.edu.au/R/e4/help/08/05/12088.html
Andy Liaw suggests not using classwt. And according to:
http://r.789695.n4.nabble.com/R-help-with-RandomForest-classwt-option-td817149.html
it has "not been implemented" as of 2007.
2011 Dec 15
2
Random Forest Reading N/A's, I don't see them
After checking the original data in Excel for blanks and running Summary(cm3)
to identify any null values in my data, I'm unable to identify an instances.
Yet when I attempted to use the data in Random Forest, I get the following
error. Is there something that Random Forest is reading as null which is not
actually null? Is there a better way to check for this?
> library(randomForest)
>
2004 Jan 20
1
random forest question
Hi,
here are three results of random forest (version 4.0-1).
The results seem to be more or less the same which is strange because I
changed the classwt.
I hoped that for example classwt=c(0.45,0.1,0.45) would result in fewer
cases classified as class 2. Did I understand something wrong?
Christian
x1rf <- randomForest(x=as.data.frame(mfilters[cvtrain,]),
2009 Jun 18
1
Can I estimate strength and correlation of Random Forest in R package " randomForest"?
Hello!
I want to estimate strength and correlation of RandomForest, but in package "randomForest" there is not an interface to get it. I think I must to change the source code. Is there any advise?
Thanks,
Li
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2010 Oct 22
2
Random Forest AUC
Guys,
I used Random Forest with a couple of data sets I had to predict for binary
response. In all the cases, the AUC of the training set is coming to be 1.
Is this always the case with random forests? Can someone please clarify
this?
I have given a simple example, first using logistic regression and then
using random forests to explain the problem. AUC of the random forest is
coming out to be
2009 Feb 26
1
Random Forest confusion matrix
Dear R users,
I have a question on the confusion matrix generated by function randomForest.
I used the entire data
set to generate the forest, for example:
> print(iris.rf)
Call:
randomForest(formula = Species ~ ., data = iris, importance = TRUE,
keep.forest = TRUE)
confusion
setosa versicolor virginica class.error
setosa 50 0 0 0.00
2012 Oct 22
1
random forest
Hi all,
Can some one tell me the difference between the following two formulas?
1. epiG.rf <-randomForest(gamma~.,data=data, na.action = na.fail,ntree =
300,xtest = NULL, ytest = NULL,replace = T, proximity =F)
2.epiG.rf <-randomForest(gamma~.,data=data, na.action = na.fail,ntree =
300,xtest = NULL, ytest = NULL,replace = T, proximity =F)
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2010 Jul 20
1
Random Forest - Strata
Hi all,
Had struggled in getting "Strata" in randomForest to work on this.
Can I get randomForest for each of its TREE, to get ALL sample from some
strata to build tree, while leaving some strata TOTALLY untouched as oob?
e.g. in below, how I can tell RF to,
- for tree 1 in the forest, to use only Site A and B to build the tree,
while using the WHOLE Site C data for the oob error
2010 Aug 06
1
Error on random forest variable importance estimates
Hello,
I am using the R randomForest package to classify variable stars. I have
a training set of 1755 stars described by (too) many variables. Some of
these variables are highly correlated.
I believe that I understand how randomForest works and how the variable
importance are evaluated (through variable permutations). Here are my
questions.
1) variable importance error? Is there any ways
2010 Mar 01
1
Random Forest prediction questions
Hi,
I need help with the randomForest prediction. i run the folowing code:
> iris.rf <- randomForest(Species ~ ., data=iris,
> importance=TRUE,keep.forest=TRUE, proximity=TRUE)
> pr<-predict(iris.rf,iris,predict.all=T)
> iris.rf$votes[53,]
setosa versicolor virginica
0.0000000 0.8074866 0.1925134
> table(pr$individual[53,])/500
versicolor virginica
0.928
2007 Oct 11
1
random forest mtry and mse
I have been using random forest on a data set with 226 sites and 36
explanatory variables (continuous and categorical). When I use
"tune.randomforest" to determine the best value to use in "mtry" there
is a fairly consistent and steady decrease in MSE, with the optimum of
"mtry" usually equal to 1. Why would that occur, and what does it
signify? What I would
2008 May 05
1
Count data in random Forest
Hello R-user!
I am running R 2.7.0 on a Power Book (Tiger). (I am still R and
statistics beginner)
I try to find the most important variables to divide my dataset as
given in a categorical variable using randomForest.
Is randomForest() able to deal with count data?
Or is there no difference because only the ranks are used in the trees?
Thanks in advance
Birgit
Birgit Lemcke
Institut f?r