similar to: question on isoMDS

Dear useRs, last week I asked you about a problem related to isoMDS. It turned out that in my case isoMDS was trapped. Nonetheless, I still have some problems with other data sets. Therefore I would like to know if anyone here has experience with how well isoMDS performs in comparison to other non-metric MDS routines, like Minissa. I have the feeling that for large data sets with a high

Hello This is a simple question but I couldn't google an answer. In the procrustes function of the vegan package, one uses plot(procrustes_object, kind=2) to obtain a plot of the residual differences. For instance: data(varespec) vare.dist <- vegdist(wisconsin(varespec)) library(MASS) mds.null <- isoMDS(vare.dist, tol=1e-7) mds.alt <- isoMDS(vare.dist,

Dear List, I am writing a custom panel function and xyplot method to plot the results of a procrustes analysis from the vegan package. I am having trouble getting the call to panel.arrows to work as I wish when conditioning. The attached file contains the function definitions for the xyplot method and the custom panel and prepanel functions I am using. This example, using data and functions from

hi all, is there a new mechanism in R 2.3.0 for copying libraries from, say, R 2.2.1 to R 2.3.0? i ask because gabor grothendieck comments in his copydir.bat (from gabor's batchfiles at: http://cran.r-project.org/contrib/extra/batchfiles/batchfiles_0.2-5.zip ): ``:: I personally upgraded my 2.1.0 to 2.2.0 this way so it seems ok until :: R replaces this with something better which is

R version 1.8.1, OS Windows 98 Dear colleagues, if I import vegetation data (first row with column labels and first column with row labels) like 7MYRGERM;7AGRGIGA;7DRYOCTO;5MYRGERM;7SALELEA;7CHOCHON;7SALNIG?;....... t401;5;2;2;3;4;2;2;2;1;2;1;2;2;1;2;2;2;1;2;1;0;0;...... t403;3;0;0;6;4;0;3;0;0;3;0;0;0;0;3;0;0;0;2;0;2;0;..... with read.table("data.file", header=TRUE,

dear R-friends, i`ve got a large dataset of vegetation-samples with about 500 variables(=species) in the following format: 1 spec1 1 spec23 1 spec54 1 spec63 2 spec1 2 spec2 2 spec253 2 spec300 2 spec423 3 spec20 3 spec88 3 spec121 3 spec200 3 spec450 . . this means: sample 1 (grassland) with the species (=spec) 1, 23, 54, 63 is it possible to get a following data-structure for further

If tbl is an object of class 'dist', you can do this: a <- sammon(tbl, k=3) But you can't do this: b <- isoMDS(tbl, k=3) Wouldn't it be sensible to have identical interfaces to sammon() and isoMDS() ? I think all that would be needed is to change this: isoMDS <- function(d, y=cmdscale(d, 2), maxit=50, trace=TRUE) { ...into this: isoMDS <-

Hi, For example: I built a half matrix "w" using a daisy(x, metric = c("euclidean")) http://www.nabble.com/file/p25211016/1.jpg And next I transformed this matrix "w" using isoMDS function, for example isoMDS(w, k=2) and as result I got: http://www.nabble.com/file/p25211016/2.jpg And now I have two questions: 1. If number in matrix w[2, 1] (= 0.41538462) match

Hi, I'm trying to use isoMDS to project a directed graph to 2-dim vectors, but I got an error. #here is the code to create the graph using igraph package and run isoMDS on it. library(igraph) library(MASS) g<-make_graph(c(1,2, 2,3, 2,4, 3,4, 4,5, 5,6, 3,6, 1,6, 2,5),directed=TRUE) dist<-distances(g, mode="out") loc<-isoMDS(dist) # below is content of the dist matrix

When I type "isoMDS()" in the R environment, a error shows up: no such function "isoMDS". Why? And what should I do to use isoMDS? Additionally, I cannot install add-on packages. Typing "Rcmd.exe INSTALL e:/VR_7.2-44.zip" results in "'perl' is neither command nor executable file...". Why this happens?Thanks. The setup file I downloaded is

Hi all, I try to calculate the stress of a configuration using the formula in the isoMDS help, but I don't have the same result than the stress returned by isoMDS : > library(mva) > library(MASS) > data(swiss) > swiss.x <- as.matrix(swiss[,-1]) > swiss.dist <- dist(swiss.x) > swiss.mds <- isoMDS(swiss.dist) initial value 2.979731 iter 5 value 2.431486 iter 10

I am starting with a matrix in which rows are vegetation plots and columns are various characteristics including ID# and elevation. I removed elevation and ID columns to avoid having those characteristics influence the distances between points which I calculated using the "dist" command. The resulting distance file was then used in isoMDS. What I want to know is whether I can

I'm not sure this belong here... Package: MASS Version: 6.2-8 I get a core dump when I call isoMDS with an incorrect argument for y. With d as an object of class "dist": > isoMDS(d,2) Program received signal SIGSEGV, Segmentation fault. 0x40229e43 in VR_mds_init_data () at MASS.c:157 --please do not edit the information below-- Version: platform = i586-pc-linux-gnu

I apply isoMDS to my data, but the result turns out to be bad as the stress value stays around 31! Yeah, 31 ,not 3.1... I don't know if I ignore something before recall isoMDS. My code as follow: m <- read.table("e:/tsdata.txt",header=T,sep=",") article_number <- ts(m, start = 2004,end=2008, frequency = 1 ,names=colnames(m))

Hi, this is a second try to post this to the R-help mailing list. The first one has been rejected because of a too large attachment. Now I ask this without attaching the data. If you want to reproduce the results, please contact me directly to get the data. (First mail, rejected:) > Attached there is a 149*149 dissimilarity matrix; it is a file obtained by >

> Date: Tue, 29 Feb 2000 17:03:51 +0100 (MET) > From: Andrea Rossetti <rossetti at markov.stat.unipg.it> [Mail to your address is undeliverable!!!] > I do this > > > valumod<-read.table("valu-medie.txt",header=T) > > library(mass) > > library(mva) > > valumod.x <- as.matrix(valumod) > > valumod.dist<-dist(valumod.x) > >

Hi I have just (finally) started to poke around in R and wanted to analyse a stream fish dataset with 28 sites and 18 species. When trying to follow the Vegan manual to run nmds from distance measures calculated by the vegdist function it turns out that I have two sites (streams) with the exactly the same four species (I have used pres-abs data in this case). When I try to run isoMDS I get an

Hi to all, I do this > valumod<-read.table("valu-medie.txt",header=T) > library(mass) > library(mva) > valumod.x <- as.matrix(valumod) > valumod.dist<-dist(valumod.x) > valumod.mds <- isoMDS(valumod.dist) Error in isoMDS(valumod.dist) : zero or negative distance between objects 2 and 4 > Where is the error? Andrea Rossetti. PS I've attached the

Hi, I'm trying to do a non-metric multidimensional scaling using isoMDS. However, I have some '0' distances in my data, and I'm not sure how to deal with them. I'd rather not drop rows from the original data, as I am comparing several datasets (morphology and molecular data) for the same individuals, and it's interesting to see how much morphological variation can be

hi R-users, a few days ago R 2.2.1 came out. on my win xp i'installed R 2.2.0. along the time i've installed a lot of contributed packages. my internet-connection is not very fast. so my question: is it possible after installing R 2.2.1 to do copy/paste the contributed packages from the C:\Programme\R221 to the C:\Programme\R2.2.1- location in the files system? or have i to download