Displaying 20 results from an estimated 20000 matches similar to: "CART vs. Random Forest"
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.
2003 Jul 09
2
CFP: CART Data Mining Conference 2004
Apologies for cross posting....
---------------------------------------------------------------------
CART Data Mining'04: First International CART(R) Conferences
Focusing on the Data Mining technology of
Leo Breiman, Jerome Friedman, Richard Olshen, Charles Stone
(CART, MARS(R), TreeNet(tm), PRIM(tm)...)
First Call For submissions
2004 May 12
1
Random Forest with highly imbalanced data
Hi group,
I am trying to do a RF with approx 250,000
cases. My objective is to determine the risk factors
of a person being readmitted to hospital (response=1)
or else (response=0). Only 10%, or 25,000 cases were
readmitted. I've heard about down-sampling and class
weight approach and am wondering if R can do it. Even
some reference to articles will help.
>From the statistical point
2007 Jan 28
2
help with RandomForest classwt option
Hello there,
I am working on an extremely unbalanced two class classification problems. I
wanna use "classwt" with "down sampling" together. By checking the rfNews()
in R, it looks that classwt is not working yet. Then I looked at the
software from Salford. I did not find the down sampling option. I am
wondering if you have any experience to deal with this problem. Do you
2000 Mar 20
1
CART and the `tree' contrib package
Dear R people,
I was recently reading the book `Classification and Regression Trees' by
Breiman. This book talks about the CART program. Both Splus and R have
implementations of this. However, the book talks about the possibility of
extending the existing `standard' set of questions (for continuous
variables, these are of the form X < c where X is the variable, c some
const) to
2008 Jul 21
2
CART and CHAID
Can I say that RPART is a modified algo of CART and PARTY a modified of
CHAID?
Thanks.
----
Chua Siang Li
Consultant - Operations Research
Acceval Pte Ltd
Tel: 6297 8740
Email: siang.li.chua at acceval-intl.com
Website: www.acceval-intl.com
This message and any attachments (the "message"...{{dropped:12}}
2004 Feb 01
2
CART: rapart vs bagging
Hi,
Is here anyone knows the difference between rapart and bagging when grow a
CART tree?
Thanks
Qin
2007 Jan 04
3
randomForest and missing data
Does anyone know a reason why, in principle, a call to randomForest
cannot accept a data frame with missing predictor values? If each
individual tree is built using CART, then it seems like this
should be possible. (I understand that one may impute missing values
using rfImpute or some other method, but I would like to avoid doing
that.)
If this functionality were available, then when the trees
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,]),
2003 Aug 20
2
RandomForest
Hello,
When I plot or look at the error rate vector for a random forest
(rf$err.rate) it looks like a descending function except for a few first
points of the vector with error rates values lower(sometimes much lower)
than the general level of error rates for a forest with such number of trees
when the error rates stop descending. Does it mean that there is a tree(s)
(that is built the first in
2010 Mar 01
1
Random Forest prediction questions
Hi,
I need help with the randomForest prediction. i run the folowing code:
> iris.rf <- randomForest(Species ~ ., data=iris,
> importance=TRUE,keep.forest=TRUE, proximity=TRUE)
> pr<-predict(iris.rf,iris,predict.all=T)
> iris.rf$votes[53,]
setosa versicolor virginica
0.0000000 0.8074866 0.1925134
> table(pr$individual[53,])/500
versicolor virginica
0.928
2006 Jan 25
1
imbalanced classes
Hi Andy,
I know this topic has been discussed before on the R-help, but I was
wondering if you could offer some advice specific to my application.
I'm using the R random forest package to compare two classes of data,
the number of cases in each class relatively low, 28 in class 1 and 9
in class 2. I'd really like to use R environment to analyze this data,
however I'm finding it
2003 Apr 12
5
rpart vs. randomForest
Greetings. I'm trying to determine whether to use rpart or randomForest
for a classification tree. Has anybody tested efficacy formally? I've
run both and the confusion matrix for rf beats rpart. I've looking at
the rf help page and am unable to figure out how to extract the tree.
But more than that I'm looking for a more comprehensive user's guide
for randomForest including
2007 Feb 07
1
The Depot "Add to Cart" sessions question (2.ed agile book)
Hello,
Im in the process of working my way through the 2.ed of the agile book.
As many of you already know, the book goes through the regular
development cycle of the Depot application. I have hit a wall
when they started talking about the sessions and the exact mechanics of
how an item is added to the session.
The code looks like this:
depot/app/controllers/store_controller:
def add_to_cart
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.
2004 Feb 09
0
CART Data Mining 2004 Conference, San Francisco, SCHEDULE information
Apologies for cross posting
CART Data Mining 2004, San Francisco, March 22-24, 2004
Below are links for the registration and the
latest scheduling information. Please note that you can register with an early-bird
discount if you register NOW and write the words "SCHEDULE" on your
registration form.
Homepage: http://www.cartdatamining.com
Detailed Conference Schedule:
2005 Nov 22
1
What? - 500 unless class Cart included
I have been struggling with a problem for a while, and now have a
workaround, but I want to understand if something is borked in my
config or if this is a bug.
Setup: Mac OS X 10.4.3; Ruby 1.8.2; Rails 0.14.3
Problem: When I create a brand new project, I get an HTTP 500 status.
If I add a Cart model, the 500 goes away:
$ rails test
create
create app/controllers
[etc]
2005 Dec 14
9
Passing quantity in a shopping cart
I am using this line on my index.rhtml page to capture the quantity
required of a particular item for a basic shopping cart app:
<%= text_field ''line_item'', ''quantity'', {:size=>3} %> </td>
but my next screen (a cart screen) doesn''t reflect what was entered in
that text field when the item is added to the cart. That is,
2006 Aug 07
2
Newbie question about adding product to cart
Hello. I''m using the Agile Web Dev. book 1st Edition and I''m puzzled by
the code on pp. 83-84.
<%= link_to ''Add to Cart'', {:action => ''add_to_cart'', :id => product },
:class => ''addtocart'' %>
def add_to_cart
product = Product.find(params[:id])
@cart = find_cart
2006 Jun 26
5
Newbie question about Agile Rails book - Delete from cart
I have been working through the Agile Web Development with Rails book
doing the Depot tutorial. I have completed it and it works but I cant
say I understand how and why.
My question is this "After adding products to the Cart, how do I then
give users the option to delete just one item and not empty the whole
cart?"
I''ve been playing around with all sorts of code, just making