Displaying 20 results from an estimated 90 matches similar to: "FW: multivariate splits"
2006 Jun 19
5
multivariate splits
Dear R users!
Does someone know about any algorithms / packages in R, that perform
classification / regression / decision trees using multivariate
splits?
I have done some research, but I found nothing. Packages "tree" and
"rpart" seem only to be able to do CART with univariate splits.
Thank you for your help!
B?lint
--
Cz?cz B?lint
PhD hallgat?
BCE KTK Talajtan ?s
2004 Feb 17
0
New package -- mvpart
The package mvpart is now available.
mvpart includes partitioning based on (1) multivariate numeric responses and
(2) dissimilarity matrices.
The package mvpart is a modification of rpart --
-- authors of original: Terry M Therneau and Beth Atkinson
<atkinson at mayo.edu>, and
R port of rpart Brian Ripley <ripley at stats.ox.ac.uk>.
Includes some modified routines from vegan --
2004 Feb 17
0
New package -- mvpart
The package mvpart is now available.
mvpart includes partitioning based on (1) multivariate numeric responses and
(2) dissimilarity matrices.
The package mvpart is a modification of rpart --
-- authors of original: Terry M Therneau and Beth Atkinson
<atkinson at mayo.edu>, and
R port of rpart Brian Ripley <ripley at stats.ox.ac.uk>.
Includes some modified routines from vegan --
2006 Feb 16
0
sums of absolute deviations about the median as split function in rpart
Dear R community,
as stated in Breiman et.al. (1984) and De'Ath & Fabricius (2000) using
sums of absolute deviations about the median as an impurity measure
gives robust trees.
I would like to use this method in rpart.
Has somebody already tried this method in rpart? Is there maybe already
a script available somewhere?
I am aware of the possibility to define usersplits myself with
2007 Aug 28
0
Variance explained by cluster analysis
Hello,
As suggested in "De'ath, 2002. Multivariate regression trees: A new
technique for modelling species-environment relationships. Ecology, 83
(4):1105-1117" (for those interested), I am trying to compare the
performance of a multivariate regression tree to a cluster analysis.
A simple partitioning with k clusters (as done by `pam`) seemed
straightforward and appropriate
2012 Apr 24
0
mvpart versus SPSS
I have a question relating to mvpart, which I hope you can answer.
We recently conducted a study using TBR. In our first study, we used
"regular" TBR in SPSS to model 1 dependent variable. Note we have a
relatively small data-set of 100 cases. In SPSS, we used a minimum change of
improvement smaller than 0.000001 as a stopping rule. Also, we chose the 1SE
"rule", set the
2006 Mar 08
1
function gdist, dist and vegdist in mvpart
Dear R community,
I am analyzing plant communities with the function mvpart, using a
dissimilarit matrix as input. The matrix is calculated with the funtion
gdist.
fit <- mvpart(gdist (ba12[,18:29], meth="maximum", full=TRUE,
sq=F) ~ beers + slope_dem + elev_dem+ plc_dem + pr_curv+
+curv+max_depth+doc_rocks+ abandon+land_use+ca_old,
data=ba12, xv="p")
This
2010 Feb 14
1
Dimensional reduction package
Is there any R package which implements non-linear dimensionality reduction (LLE, ISOMAP, GTM, and so on) and/or intrinsic dimensionality estimation ?
Thank you,
Maura
tutti i telefonini TIM!
[[alternative HTML version deleted]]
2004 Oct 24
1
How to use a matrix in pcurve?
Hi, Everyone,
I want to calculate the principal curve of a points set.
First I read the points'coordinate with function "scan",
then converted it to matrix with the function "matrix",
and fit the curve with function "principal.curve".
Here is my data in the file "bmn007.data":
0.023603 -0.086540 -0.001533
0.024349 -0.083877 -0.001454
..
..
2009 Dec 15
1
user-written splits in rpart
Hi,
I am trying to write my own split function for rpart. The aim is to do, instead of anova, a linear regression to determine the split (minimize some criterion like sum of rss left and right of the split). The regression (lm) should simply use the dependent and independent variables passed to rpart.
I am aware of the example provided in the rpart source code, but stumbled on similar problems
2001 May 22
1
Surrogate splits for decision trees
Dear R,
Short verse of the question:
Is there R code which will calculate surrogate splits
and/or delta impurity for decision trees at each node?
Long Version:
I have local, legacy code which I use to calculate my decision trees.
I would like to switch to R, but as I understand it surrogate splits
are not implemented.
Surrogate splits and feature ranking are described in Breiman et al
2009 Nov 06
1
R splits character fields in a csv file
I download a csv extract from a database and use read.csv to read it
from R and when there are large character fields with embedded blanks,
slashes etc. - R often sees one line as two lines (or more).
I verfied with readLines that an embedded blank in a character field
causes a spurious new line to be seen.
I am sure this problem has beem seen before - and would appreciate any
help in reading
2011 May 19
1
Specifying Splits WhenUusing rpart
I am using the package rpart to explore various classification structures.
The call looks like:
seekhi1<-rpart(pvol~spec+a1+psize+eppres+numpt+icds+bivalcrt+stents+ppshare+
nhosp+nyrs,data=dat,method="class",
control=rpart.control(minsplit=30,xval=10))
The output is
1) root 198 87 1 (0.5606061 0.4393939)
2) psize=1,2 122 43 1 (0.6475410 0.3524590)
2012 Apr 15
0
Specifying splits - in read.csv.ffdf
Hi All,
I am currently trying to familiarize with "ff" package which allows me to store R objects in the hard drive. One of things that I notice when reading in a text file with "read.csv.ffdf" function - is that, in the R temp folder, 1000+ small files get created, each file having a name like "ffdf1bcd8b4aa0.ff". Each file is about 5KB in size.
My understanding
2012 May 30
1
gsub/strsplit with multiple patterns/splits
Hi,
I have a vector like this:
DF <- c("Aetna, Inc.", "Alexander's Inc.", "Allegheny Energy, Inc")
For each element in the vector I would like to remove the "incorporated"
info, so that my vector looks like this:
DF <- c("Aetna", "Alexander's", "Allegheny Energy")
That means that I have to strip:
strip <-
2015 Jan 07
0
rsync splits filenames, creates special characters where none are, weird permissions
On Wed 07 Jan 2015, Lenz Weber wrote:
> Where the local destination /data/snapshots is an NFS volume mounted with the flags
> (rw,noatime,addr=192.168.1.XX)
> and the source is a symlink to a zfs snapshot - that looks like this:
> /var/backups/mail -> /tank/mail/.zfs/snapshot/zfs-auto-snap_hourly-2015-01-07-1417
Why not skip the NFS part and run rsync to the destination
2003 Mar 11
2
system(..., intern=TRUE) splits long lines (PR#2623)
system(..., intern=TRUE) splits long lines after 118th character and
discards the 119th character
> a <- paste(rep("a", 124), collapse="")
> system(paste("echo", a), intern=TRUE)
system(paste("echo", a), intern=TRUE)
[1]
"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
2007 Oct 23
1
Multivariate regression tree: problems with surrogate splits
R helpers,
I am working with the R program performing multivariate regression trees (MRT). I have a matrix with species and environmental variables saved as a CSV file (sprot_matrix.csv), I have 42 species and 8 environmental variables (SECCHI+PH+TA+PTOT+NTOT+CHLA+AREA+ MEANDEP) for 104 samples
Title
SpA
SpB
SpC
SpD
Varible1
Variable2
Variable3
Sample1
Sample 2
2002 Aug 15
2
complex splits
Hi everyone,
I'm having trouble figuring out how to split a dataframe more than once.
Let's say I have a dataframe d with a certain column called splitcol
composed of four possible ordinal values. The same dataframe has
two other columns, col1 and col2, that have one of two possible values
each. I'd like to split d$splitcol based on col1 and col2 so I can report
frequencies of the
2012 Dec 19
2
create stratified splits
Hi,
I have a vector like:
r <- runif(100)
Now I would like to split r into 10 pieces (each with 10 elements) ?
but the 'pieces' should be roughly similar with regard to mean and sd.
what is an efficient way to do this in R?
thanks!