Displaying 20 results from an estimated 3000 matches similar to: "random forest proximities"
2003 Sep 03
2
lme in R and Splus
Good Day,
Included below is some code to generate data and to fit a mixed effects
model to this fake data. The code works as expected when I call the
function "lme" in Splus but not in R.
The error message from calling lme in R is:
"Error in getGroups.data.frame(dataMix, groups) :
Invalid formula for groups"
I installed the nlme package for R around 20 August
2002 May 28
0
random Forests
Hi,
I have a data set with 1000 observations and 260 predictors. The
predictor variables are all ordinal. There are 2 classes labeled as, F
and T with class proportions of 0.44 and 0.56, respectively.
In a call to the function randomForest() with mytry=1 and nodesize=1 and
ntree=100 the resulting classifier puts all observations in class T.
When I change nodesize to nodesize=5 I get the
2002 Mar 21
0
tree
Hi,
I have a dataframe, y, with 1000 rows and 266 columns. The first column
of y is a 2 level factor response; columns 2:266 are each ordinal
variables that can take on one of the values 1, 2, or 3.
I'm trying to fit a model with the calls:
(A) y.tree <- tree(pref~.,data=y,mindev=0,minsize=2)
and
(B) y.tree <- tree(pref~.,data=y,split='gini')
pref is the name of the factor
2002 Feb 13
3
xtabs
Hi,
In Splus if I call the function crosstabs() the output is a contigency
table; in each cell of the table is printed: N, N/RowTotal,
N/ColTotal, N/Total. N is the number of observations in each cell.
The same call to xtabs() in R will produce the contigency table but the
only entry in each cell is N.
How can I get the same relative frequencies that crosstabs() gives?
Thanks,
mike
--
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,]),
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.
2000 Jun 28
1
F-secure -> Openssh Compatibility (fwd)
Date: Tue, 27 Jun 2000 16:09:43 -0600 (MDT)
From: "W. Scott Wilburn" <wilburn at lanl.gov>
To: ssh at clinet.fi
Subject: F-secure -> Openssh Compatibility
We have Macintoshes running Fsecure SSH client 1.0.1 which are unable to
connect to a server running Openssh 2.1.1 on Red Hat 6.2.
I believe that the problem is a bug with Fsecure, since a 30-day trial
version of 1.0.2 works
2004 Oct 13
1
random forest -optimising mtry
Dear R-helpers,
I'm working on mass spectra in randomForest/R, and following the
recommendations for the case of noisy variables, I don't want to use the
default mtry (sqrt of nvariables), but I'm not sure up to which
proportion mtry/nvariables it makes sense to increase mtry without
"overtuning" RF.
Let me tell my example: I have 106 spectra belonging to 4 classes, the
2007 Sep 25
2
3d barplot in rgl
Is there anyway to plot a matrix using a 3d bar plot. Something like
bar3 in matlab?
The example in demo hist3d does a 3d barplot for binned data, but has
anyone tried something for a simple matrix with spaces betwen bars
and axis labels using matrix dimnames or 1,2,3?
stages<-letters[1:3]
A<-matrix(c(
0.21, 0.21,0.03,
0.55, 0.58, 0.09,
1.30, 1.35, 0.22), nrow=3, byrow=TRUE,
2008 Oct 28
0
Random Forest Bug
Dear help list,
I think I found a bug a the R Random Forest. Hopefully, you are able to
reproduce it.
I use R version 2.7.2 and RF version 4.5-27.
This is a minimal code to describe the problem:
library(randomForest)
tries <- 20
dimension <- 20
n <- 200
outlyingness <- rep(NaN,tries)
for (o_number in 1:tries){
features <- matrix(rnorm(n*dimension,0,1),n,dimension)
#Generate
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)
[[alternative HTML version deleted]]
1999 Nov 29
2
Food for thought regarding PAM
I'm new to this list, so please forgive me if this has been discussed
before.
It appears that one of the (commendable) design goals of OpenSSH is to
re-use existing open-source libraries wherever possible in order to
simplify the OpenSSH code and hopefully improve security in the process.
As exhibited by the current, non-open SSH, supporting all of the nuances
of authentication and logins
2005 Oct 27
1
Repost: Examples of "classwt", "strata", and "sampsize" i n randomForest?
"classwt" in the current version of the randomForest package doesn't work
too well. (It's what was in version 3.x of the original Fortran code by
Breiman and Cutler, not the one in the new Fortran code.) I'd advise
against using it.
"sampsize" and "strata" can be use in conjunction. If "strata" is not
specified, the class labels will be used.
2012 Oct 17
0
How to optimize or build a better random forest?
Hello Everyone!
It's been a while since I last posted a question! Hope everyone has been
doing well!
~~~ CONTEXT ~~~
I have recently entered a beginner-level competition on kaggle. The
goal of the competition is to build a model that predicts who did/did not
survive on the Titanic.
I decided to use random forests as I have been wanting to learn the
algorithm and the competition
2010 Oct 21
1
RandomForest Proximity Matrix
Greetings R Users!
I am posting to inquire about the proximity matrix in the randomForest
R-package. I am having difficulty pushing very large data through the
algorithm and it appears to hang on the building of the prox matrix. I have
read on Dr. Breiman's website that in the original code a choice can be made
between using an N x N matrix OR to increase the ability to compute large
2008 May 21
1
How to use classwt parameter option in RandomForest
Hi,
I am trying to model a dataset with the response variable Y, which has
6 levels { Great, Greater, Greatest, Weak, Weaker, Weakest}, and
predictor variables X, with continuous and factor variables using
random forests in R. The variable Y acts like an ordinal variable, but
I recoded it as factor variable.
I ran a simulation and got OOB estimate of error rate 60%. I validated
against some
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
2002 Oct 04
1
Confirming kerberos for upcoming OpenSSH portable release.
O.K. I know it was too late to make changes for the next release, but
thankfully there werent any changes needed. Kerberos over ssh protocol 1
worked out of the box from CVS today (2002/10/04-14:30)
The krb5 patches we were using (I think from Olaf K) was all in the
code. The only thing I had to patch to get things working was removing
the scard-install from the Makefile.in
The compiled code
2006 Jan 23
1
Sample rows in data frame by subsets
Hi,
I need to resample rows in a data frame by subsets
L3 <- LETTERS[1:3]
d <- data.frame(cbind(x=1, y=1:10), fac=sample(L3, 10, repl=TRUE))
x y fac
1 1 1 A
2 1 2 A
3 1 3 A
4 1 4 A
5 1 5 C
6 1 6 C
7 1 7 B
8 1 8 A
9 1 9 C
10 1 10 A
I have seen this used to sample rows with replacement
d[sample(nrow(d), replace=T), ]
x y fac
7 1 7 B
2
2006 Jul 23
1
Iterated Data Input/Output with Random Forests
Hi,
I am currently writing code to input a few thousand files, run them through the
Random Forests package, and then output corresponding results.
When I use the code below:
zz<-textConnection("ex.lm.out", "w")
sink(zz)