similar to: Problems with environments, I think..

Hello list, Sorry, these questions are not directly linked to R. If I consider an indefinte real matrix, I would like to know if the symmetry of the matrix is sufficient to say that their eigenvectors are real ? And what is the conditions to ensure that eigenvectors are real in the case of an asymmetric matrix (if some conditions exist)? Thanks in Advance, St?phane DRAY

Hello List, I would like to orthonormalize vectors contained in a matrix X taking into account row weights (matrix diagonal D). ie, I want to obtain Z=XA with t(Z)%*%D%*%Z=diag(1) I can do the Gram-Schmidt orthogonalization with subsequent weighted regressions. I know that in the case of uniform weights, qr can do the trick. I wonder if there is a way to do it in the case of non uniform

Hello, suppose I have a list with matrices: a=list(x1=matrix(rnorm(10),5,2),x2=matrix(rnorm(10),5,2),x3=matrix(rnorm(10),5,2)) I want to compute for all combination of xi and xj (x1,x2 x1,x3 and x2,x3) a value. This value is given for the pair x1,x2 by trace(x1%*%t(x1)%*%x2%*%t(x2)) / trace(x1%*%t(x1))*trace(x2%*%t(x2)) I know that product matrices t(xi)%*%xi can be obtained by:

Hello List, I have create a small package with C code. In the C code, I call Fortran routines of Lapack. Here is the call in the C function: F77_CALL(dgesvd)(&jobu, &jobvt,&size, &size,A, &size, D,U,&size,V,&size,&work1, &lwork,&error); In the src directory, I have a Makevars File with: PKG_LIBS = $(LAPACK_LIBS) $(BLAS_LIBS) $(FLIBS) And in the

Hello list, my question is related to svd of a matrix: b=matrix(rnorm(50),10,5) mysvd=svd(b) I would like to compute each xi where xi = di* ui %*% t(vi). I do it by : xlist=sapply(1:ncol(b), function(x1,y) y$d[x1]*y$u[,x1]%*%t(y$v[,x1]),y=mysvd,simplify=F) # result is a list xarray=array(sapply(1:ncol(b), function(x1,y) y$d[x1]*y$u[,x1]%*%t(y$v[,x1]),y=mysvd),c(nrow(b),ncol(b),ncol(b))) #

Hello list, I have used scan function to import data into R. I have done some analysis and find strange results. I have found my problem : when importing data with scan, this can slightly modify the data : > write(c(0.251,3.399,-0.481,0.266),"essai.txt") > scan("essai.txt") Read 4 items [1] 0.251 3.399 -0.481 0.266 > print(scan("essai.txt"),17) Read

Hello list, I have 3 matrices with same dimension : > veca=matrix(1:25,5,5) > vecb=matrix(letters[1:25],5,5) > vecc=matrix(LETTERS[1:25],5,5) I would like to obtain a new matrix composed by alternating rows of these different matrices (row 1 of mat 1, row 1 of mat 2, row 1 of mat 3, row 2 of mat 1.....) I have found a solution to do it but it is not very pretty and I wonder if I

Hello, I have a question that is not directly related to R ... but I try to do it in R ;-) : I would like to generate a matrix Q satisfying (for a given Z, X and W) the two following conditions: t(Q)%*%Q=Z (1) XQ=W (2) where: Q is m rows and r columns X is p rows and m columns D is p rows and r columns C is r rows and r columns with m>p,r e.g: m=6, p=2 r=3

Hello list, I have a problem ... and do not know how to solve it. I would like create a function that estimate the quality of the fit of different functions with different values of parameters. This problem is related to the following one: I would like to create a function "evaluatemyfunction" which evaluate a function f for different values of parameters. For instance, if

Hello list, I have two vectors x and x2: x=runif(10) x2=runif(10) and one vectors with their names : my.names=c("x","x2") I would like to cbind these two vectors using their names contained in the vector my.names. I can create a string with comma ncomma=paste(my.names,collapse=",") and now, I just need a function to transform this string into a adequate

Hello all! I'm a newcomer to R, so please bear with me. My problem is the following: I'm trying to use R to do some geostatistics stuff (mostly kriging), and am having trouble printing a multiple figure. When I create a single figure (one image/contour command), it works fine. The instant I try to create a multiple figure file, I start getting postscript errors. I'm using the

I am not sure a previous e-mail reached the list (no mail aknowledgement from R-boundle etc.). The question was how to write polygon or segment coordinates into a shapefile set or any other ArcGIS supported format. The library shapefiles seems to do something but the documentation is a bit beyond of my mind.... and I cannot get the meaning of the functions write**** and its application to the case

Hello list, I am writing a paper for Rnews. I use Sweave to do it. I did not find information about writing a paper for Rnews using Sweave and have some questions: - Is there a problem to use the environment 'Sinput' in the place of 'example' or 'smallexample'. It works fine but perhaps there are some technical/editorial problems ? - I have some long lines of code in

Hello all. This may be a trivially simple question to answer, but I'm a little bit stumped with respect to the calculation of the F statistics in nested anovas in R. If I understand correctly, the F statistic for the among-subgroups but within groups hypothesis is calculated as MS_subgroups/MS_error, while the F statistic for the factor is calculated as MS_factor/MS_subgroups (I'm

Hello list, I would like to know if it is possible to get output of help(foo) with Sweave. If I insert ?foo in a chunk, the console give me the help but no output is obtained in the tex file. Perhaps something to do with options ? Thanks in advance ! -- St??phane DRAY (dray at biomserv.univ-lyon1.fr ) Laboratoire BBE-CNRS-UMR-5558, Univ. C. Bernard - Lyon I 43, Bd du 11 Novembre 1918, 69622

Hello list, I have found a problem (bug?) with Sweave. I hope that someone could help me. Try this little example : \documentclass[a4paper]{article} \title{toto} \author{toto} \begin{document} \maketitle <<ni1, fig=T, eval=TRUE, echo=TRUE, debug=TRUE, results=verbatim, include =FALSE, width=7, height=7>>= a<-rnorm(1)+1 a plot(1:10) @ patati <<ni2, fig=F, eval=TRUE,

Dear All, I am using the scatter.dudi finction in the 'ade4' package to produce correspondence analysis (nice) plots. I do not seem to figure out how to plot the raw coordinates only -- or column coordinates only. I would appreciate any help in doing that. Here is the example I am following -- from the package. data(banque) > banque.acm <- dudi.acm(banque, scann = FALSE, nf =

Does R have a function to calculate Bray-Curtis distance measures, which is probably one of the most frequently used and recommended dissimilarity measures in ecology? It isn't mentioned in dist().

Bonjour à tous, Je débute dans l'utilisation de R, et suis à la recherche de toute piste me permettant l'introduction à ce logiciel. J'ai pour le moment la fiche d'Emmanuel Paradis: "R pour les débutants", mais j'aimerais savoir où je peut trouver d'autres documentations notamment pour le traitement statistique de données (Anova, modèle linéaire et modèle

Hello I have some kind of problem with R. I want to do a pca (I work on R and ade4 library) but R doesn't wan to realize my pca because of my data: I have some binary variable (presence/absence of birds, hole, vegetals...) and metric variable (cliff 's size...) and each time I have an error message because of the mix of the 2 type of variable. So, what can I do? Famille SALMON