Displaying 20 results from an estimated 1000 matches similar to: "Dimensional reduction package"
2011 May 18
1
matrix help (first occurrence of variable in column)
Dear R help,
Apologies for the less than informative subject line. I will do my
best to describe my problem.
Consider the following matrix:
mdat <- matrix(c(1,0,1,1,1,0), nrow = 2, ncol=3, byrow=TRUE,
dimnames = list(c("T1", "T2"),
c("sp.1", "sp.2", "sp.3")))
mdat
In my actual data I have time
2010 Mar 02
1
how to import map data (maptools?) from a html set of 'coords'
Dear R users,
I would like to draw map and import it in maptools/spatstat packages.
The 'raw data' I have come from a web page (<map>...</map>) and are
basically a list of coordinates of a polygon.
I would like to know how to import them in R; I checked the maptools
packages, but all the examples use existing .dbf files.
I just have a (serie of) text file(s) looking like
2010 Feb 12
1
Problems with savePlot() and postscript under Snow Leopard
Dear all,
I tried:
> iris
> species.n <- as.numeric(Species)
> plot(iris, col = species.n)
> savePlot(filename="IrisTestPlot", type="png")
and got the error message:
Fehler in savePlot(filename = "IrisTestPlot", type = "png") :
kann nur aus 'X11(type="*cairo")' Devices kopieren
(sorry, I have a german version of R).
I
2009 Dec 14
1
lapply , mapply questions
Dear all,
i have a programming problem that should be simple, though i am stuck with it. Please note that this is not a specific geonames problem, though i use it as an example - it´s just a basic problem with lapply.
I use the geonames webservices with the R geonames packages which works almost smoothly.
I have a vector of Zipcodes and i want to do a geonames lookup for all of them, which
2010 Apr 02
2
Biplot for PCA using labdsv package
Hi everyone,
I am doing PCA with labdsv package. I was trying to create a biplot graphs
in order to observe arrows related to my variables. However when I run the
script for this graph, the console just keep saying:
*Error in nrow(y) : element 1 is empty;
the part of the args list of 'dim' being evaluated was:
(x)*
could please someone tell me what this means? what i am doing
2010 May 25
2
Calculation time of isoMDS and the optimal number of dimensions
Dear all,
I'm running a set of nonparametric MDS analyses, using a wrapper for isoMDS,
on a 800x800 distance matrix. I noticed that setting the parameter k to
larger numbers seriously increases the calculation time. Actually, with k=10
it calculates already longer than for k=2 and k=5 together. It's now
calculating for 6 hours, and counting...
There is quite a difference between the
2009 Apr 15
3
Kruskal's MDS results
Dear List,
I'm trying to interpret the results of the Kruskal's Non-metric Multidimensional Scaling algorithm (isoMDS, MASS package).
The 'goodness of fit' is reported as "The final stress achieved (in percent)".
What does this mean exactly? I've tried to google for an answer but I've not come up with a definitive answer.
Regards,
Dieter
--
Dieter Vanderelst
2011 May 10
3
metaMDS and envfit: Help reading output
Hello R experts,
I've used metaMDS to run NMDS on some fish abundance data, and am also working on correlating environmental data to the NMDS coordinates. I'm fairly new to metaMDS and NMDS in general, so I have what are probably some very basic questions. My fish abundance data consists of 66 sites for which up to 20 species of fish were identified and counted. I ran metaMDS on this data
2010 Jan 25
4
R Output and ArcGIS
Dear all,
I've been using R on a Mac to process some data for export to ArcMap GIS (which only runs on Windows). ArcMap seems to require tab-delimited data (my data are in 3 columns), so I've been using the sep="\t" argument. However, this resulted in strange end-of-line characters when displayed on a PC. I looked in the write.table help file to find that eol="\r\n"
2010 Apr 05
4
NMDS Ordination Graphics Problem
Dr. Stevens,
Hi, my name is Trey Scott, and I'm a grad student of Brian McCarthy's. He
referred me to you because of your expertise in handling complex R problems.
We were hoping you could help us solve a nagging problem that is prohibiting
me from producing graphicl output.
Here is a simple mock-up of the matrix I'm using
a b c d e f
1i 1 4
2006 Jun 15
3
MDS with missing data?
Hello
I will be applying MDS (actually Isomap) to make a
psychological
"concept map" of the similarities between N concepts.
I would like to scale to a large number of concepts,
however, the
resulting N*(N-1) pairwise similarities is prohibitive
for a user survey.
I'm thinking of giving people random subsets of the
pairwise
similarities.
Does anyone have recommendations for this
2009 Jan 21
1
vegan metaMDS
Hi,
I'm trying to use metaMDS with a dissimilarity matrix of angles, not
Bray-Curtis, and I wanted to know if there is an in-built function to
produce a plot of stress values against dimensions, that could be used to
determine the 'true' dimension of the solution. The number of objects is
only a lowly 8 so any solution higher than 2-dimensional is not likely to be
interpretable,
2009 Aug 02
1
package to convert coordiantes to timezone
Is there a R-package with a function that returns me the timezone, if
I hand over longitude and latitude?
I know online services like
http://ws.geonames.org/timezone?lat=-38.01&lng=147 and
http://www.earthtools.org/webservices.htm#timezone and wodner if this
exists for R too.
Thanks for helping,
thomas
2009 Mar 12
3
help with predict and plotting confidence intervals
Dear R help,
This seems to be a commonly asked question and I am able to run examples that have been proposed, but I can't seems to get this to work with my own data. Reproducible code is below. Thank you in advance for any help you can provide.
The main problem is that I can not get the confidence lines to plot correctly.
The secondary problem is that predict is not able to find my object
2005 Oct 05
1
pca in dimension reduction
Hi, there:
I am wondering if anyone here can provide an example using pca doing
dimension reduction for a dataset.
The dataset can be n*q (n>=q or n<=q).
As to dimension reduction, are there other implementations for like ICA,
Isomap, Locally Linear Embedding...
Thanks,
weiwei
--
Weiwei Shi, Ph.D
"Did you always know?"
"No, I did not. But I believed..."
---Matrix III
2010 Mar 02
16
Three most useful R package
Hi R-fans,
I would like put out a question to all R users on this list and hope
it will create some feedback and discussion.
1) What are your 3 most useful R package? and
2) What R package do you still miss and why do you think it would make
a useful addition?
Pulling answers together for these questions will serve as a guide for
new users and help people who just want to get a hint where to
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
2014 Sep 13
1
vegan moved to GitHub and vegan 2.2-0 is coming (are you ready?)
Dear vegan team,
Vegan development happens now completely in github. R-Forge repository is no more in sync with github. I tried to commit all github changes to R-Forge, but a week ago I got a conflict in file and I haven't had time to resolve that conflict. You can follow vegan development and vegan discussion also without signing to github. The system seems to be completely open and does not
2004 Nov 24
2
LDA with previous PCA for dimensionality reduction
Dear all, not really a R question but:
If I want to check for the classification accuracy of a LDA with
previous PCA for dimensionality reduction by means of the LOOCV method:
Is it ok to do the PCA on the WHOLE dataset ONCE and then run the LDA
with the CV option set to TRUE (runs LOOCV)
-- OR--
do I need
- to compute for each 'test-bag' (the n-1 observations) a PCA
1997 Sep 30
1
rlogin authentication bug
Hi,
I have discovered a bug in the rhost module of Linux-PAM-0.57. This
bug leads to a vulnerability in the remote login authentication, with
the effect that ordinary user accounts may not be password protected.
There is only one case when the bug causes a vulnerability:
The problem case is when the user''s .rhost file has the name of a machine
with *more than one IP address* as the