similar to: various ordinations

-----Messaggio originale----- Da: Michael Camann <camann at babylon.cnrs.humboldt.edu> A: r-help at stat.math.ethz.ch <r-help at stat.math.ethz.ch> Data: marted? 22 agosto 2000 21.02 Oggetto: [R] various ordinations >Colleagues, > >I'm developing a library of functions for community ecology analyses and >have a couple of questions that I've not been able to answer

Dear Michael Camann, My concern was after having a hetero-computing environment for many years, I found that I had to keep an old version of Microsoft Windows based applications to be able to interact with my constituents. This at times can become very expensive. I have had to limit my budget on the UNIX/Linux platform to compensate for Microsoft Windows based applications. With Open Office

Dear Michael Camann, My concern was after having a hetero-computing environment for many years, I found that I had to keep an old version of Microsoft Windows based applications to be able to interact with my constituents. This at times can become very expensive. I have had to limit my budget on the UNIX/Linux platform to compensate for Microsoft Windows based applications. With Open Office

Is there an R function that does canonical correspondence analysis. Can it be done using the VR function corresp()? If not, how hard it be to write R code to do it? I am a population biologist with long but patchy programming experience in C, Smalltalk, Java and other languages. Thanks, Patrick Foley patfoley at csus.edu

AARRGGHH! Sometimes it's the simple things that are particularly frustrating, especially late at night.... Can anyone suggest a simple means for replacing all of the zero values in a matrix with NANs? I ended up writing an awk script to massage the input file, which works, of course, but is rather an inelegant blunt instrument. I'd prefer an R operation. I'm certain that

Hope this isn't a faq, but.... I'm using R 0.99 for Windows under Win98. When I label points in a scatterplot with identify(), the labels appear as expected on the graphics device, but do not print when I select the printer icon. The scatter plot itself prints just fine-- only the output from identfy() is missing. Can anyone offer any hints? --Mike C.

R-community-- Is there a contributed package (or does anyone have code otherwise) for exact inference tests and resampling statistics ala' StatExact? I've perused the package descriptions on CRAN and didn't see anything, but since several contain many functions, I thought perhaps I'd ask. --Mike C. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Michael

R-devel team-- Will the patches that Brian Ripley has posted be rolled into the main R-win distribution on CRAN? I ask because I'm going to be using R in one of my ecology courses during fall semester, and although I'll probably give the students a CD with R and a variety of other tools bundled onto it, I'll also tell them where to upgrade and look for additional packages and other

Here's a question for ecologists on the r-help list-- I'm addressing this to ecologists in particular because they're most likely to be familiar with the equation in question but I'll be happy to discuss the problem with anyone who's willing to take a whack at it. I'm trying to write a function to calculate the large sample variance of species richness estimates by

Colleagues-- I'm having a problem upgrading to R 1.5.0 on a Windows 98 computer. The windows() graphics device seems to behave strangely. A call to windows() opens an active graphics device, as does a call to a plotting function, e.e. plot(1:5,1:5). So far so good. When I click on the Printer icon (with the graphics device active) nothing happens. Likewise when I use win.print() from the

Dear all, I'm trying to get a two dimensional embedding of some data using different meythods, among which princomp(), cmds(), sammon() and isoMDS(). I have a problem with sammon() because the coordinates I get are all equal to NA. What does it mean? Why the method fails in finding the coordinates? Can I do anything to get some meaningful results? Thank you very much Domenico

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 <-

Dear all, I didn't find any graphical solution in the package "mva" to plot the canonical scores from a CCA (canonical correlation analysis). Does anybody knows how to plot or has anybody already programmed : - the map of the canonical scores, - the graph of the canonical weights, - the correlation circle i.e. the canonical loadings ? Thank you for help ...

Dear All, I am in the somewhat unfortunate position of having to reproduce the results previously obtained from (non-metric?) MDS on a "kinship" matrix using Statistica. A kinship matrix measures affinity between groups, and has its maximum values on the diagonal. Apparently, starting with a nxn kinship matrix, all it was needed to do was to feed it to Statistica flagging that the

Hi again Sorry, in looking again at sammon and isoMDS I see that they seem to do exactly what I want, except that they are non-metric, which means, as I understand it, that they relate the rank orders of the variables rather than the actual distances. Could I use these non-metric MDS packages even if my distances are metric? Thanks Karen -- Karen Kotschy Centre for Water in the Environment

Hi, I hope someone knows the answer to this or has a real good reference about it (I am using Legendre & Legendre, Numerical Ecology, 1998).... My data is a data.frame with locations as rows and vegetation assemblages / species as columns. I've done a PCA, a correspondance analysis (CA) using ca in ca package and a detrended correspondance analysis (DCA) using decorana from vegan package.

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

Hi, I need math function which is used in: isoMDS, Sammon and metaMDS method. Anybody know where I may find it? Any manual or webside? I would be very happy Thanks a lot ! -- View this message in context: http://n4.nabble.com/math-function-MDS-method-tp1008294p1008294.html Sent from the R help mailing list archive at Nabble.com.

Hi all, I'm trying to perform an MDS of some data that I have. When I use cmdscale everything is fine and I get some interesting results however, the tends to be low. What I wnat to do is compare this with the Non-Metric MDS using isoMDS or sammon. However, when I try using these I get the following message. Error in isoMDS(x.dist) : zero or negative distance between objects 2 and 4

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