Displaying 20 results from an estimated 1100 matches similar to: "lda: how to get the eigenvalues"
2008 Apr 01
1
superimpose histogram on biplot
Hi all,
I've been trying to figure out how to superimpose a histogram on a
biplot that shows the relative contribution of each axis. I have
been using the NIPALS function (http://biomserv.univ-lyon1.fr/~dray/
files/softwares/nipals.R) to run principal component analyses. Here
is a toy example.
source("http://biomserv.univ-lyon1.fr/~dray/files/softwares/nipals.R")
2006 Dec 05
1
Cummulative Variance in Correspondence Analysis (ADE4)
Hi all:
How can I calculate the cumulative variance (or variance for each component)
in correspondence analysis?
If were possible in ADE4 package
Thank you
-- Antonio Punzón Merino
O__---- Instituto Español de Oceanografía
c/ /'_ --- Centro Oceanográfico de Santander
(*) \(*) -- Promontorio de San Martín S/N
~~~~~~~~~~ 39004-Santander; Spain
PO BOX: 240
Tlf: +34 942 29 10 60
Fax: +34
2006 May 03
2
mca id numbers
Is it possible to make disappear the id numbers from scatter.dudi (mc
analysis) ?
a <- as.factor(c(1, 2, 3, 2, 1))
b <- as.factor(c(3, 2, 3, 1, 1))
x <- as.factor(c(1, 2, 2, 1, 3))
y <- as.factor(c(2, 2, 3, 1, 1))
dat <- data.frame(a=a, b=b,x=x,y=y)
summary(dat)
dat
require(ade4)
dat.acm <- dudi.acm(dat, scann = FALSE, nf = 2)
scatter.dudi(dat.acm)
Thank you very much !
2003 Dec 20
7
error bars around a point
All
Is there an R command to produce error bars around
a plotted point. Crawley's book uses the command
error.bar() but my version of R rejects it. Must be an
S+ command(?).
Thanks
REX
[[alternative HTML version deleted]]
2003 Apr 18
1
stepwise discriminant analysis
Hi all,
is it possible to do stepwise discriminant analysis (linear amnd non-linear)
in R?
If yes- which package does it|?
Thanks
Janine
--------------------------------------------
"El gesto y la palabra son el pensamiento del hombre"
Isabel Allende
Janine Illian
lecturer in statistics
SIMBIOS
School of Computing
University of Abertay Dundee
Bell Street
Dundee, DD1 1HG
Scotland,
2004 Mar 24
7
binding vectors or matrix using their names
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
2004 Sep 20
4
Multiple operations on list
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:
2004 Feb 23
2
orthonormalization with weights
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
2003 Nov 04
2
real eigenvectors
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
2004 Oct 22
4
Evaluate a function for various value of parameters
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
2004 Jul 06
2
Generate a matrix Q satisfying t(Q)%*%Q=Z and XQ=W
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
2004 Mar 31
3
scan seems to modify the data
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
2004 Jul 09
3
analytic solution for equation
Hello,
I have search on R website but do not find any solution.
I would like to know if R has some functionalities to produce analytical results
of equation. or more generally if it contains some functions to simplify equation.
For example:
I would like to obtain x1 from:
x1+x2=8 (x1=8-x2)
x1^2+x2=8 (x1=sqrt(8-x2))
Is is possible in R ? if not, do you know a (free) software that could do the
2006 Mar 26
3
Using a Gem in your App without installing to the system
Does anyone know how to use a gem without installing it to the rails
installation? For example, I can download the Money gem package from
http://dist.leetsoft.com/ but if I don''t have the ability to install a
gem at my hosting provider, how can I use the gem in my app?
Cheers,
Dan
2004 Jul 03
1
graphic representation of a qda object
Hi,
I'm a R newbie and I have a supervised 2-class classification problem.
To find out the best representation of my data (dim = 45). I want to perform LDA und QDA on the diffrent data representations to find out, which is best to discriminate the 2 sets. For LDA there exists a method plot.lda shows (in the 2 class case) a histogramm of the data, projected onto the linear discriminants (pleas
2007 Nov 16
1
Efficient way to compute power of a sparse matrix
Dear all,
I would like to compute power of a square non symmetric matrix. This is
a part of a simulation study. Matrices are quite large (e.g., 900 by
900), and contains many 0 (more than 99 %). I have try the function
mtx.exp of the Biodem package:
library(Biodem)
m <- matrix(0, 900, 900)
i <- sample(1:900, 3000, replace = T)
j <- sample(1:900, 3000, replace = T)
for(x in 1:3000)
2004 Jun 29
2
binding rows from different matrices
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
2001 May 29
3
geary statistics
Hello,
i' m looking for a function to compute geary statistic for spatial correlation.
Thanks.
--
St?phane DRAY
---------------------------------------------------------------
Biom?trie et Biologie ?volutive - Equipe "?cologie Statistique"
Universite Lyon 1 - Bat 711 - 69622 Villeurbanne CEDEX - France
Tel : 04 72 43 27 56 Fax : 04 78 89 27 19
04 72 43 27 57 E-mail
2009 Jan 04
1
Customized LDA (MASS) object plot
Hi R experts.
I performed an Linear Discriminant Analysis (lda) and now I want to plot the
first two axes (LDA1 and LDA2). Well MASS package have the plot.lda and
pairs.lda to do that. But, they don’t let me personalize them, once they
don’t accept the type=’n’ plot. So I start looking at the lda object
properties, trying to found out my groups (n=4) axis coordinates, curiously
I couldn’t. There
2002 Jul 18
2
RODBC and Excel Files
Hello,
I am trying to play with RODBC library and Excel Files. In my file
(doubs.xls) there are 2 spreadsheets:
> library(RODBC)
> connection<-odbcConnect("Excel Files")
> sqlTables(connection)
TABLE_CAT TABLE_SCHEM TABLE_NAME TABLE_TYPE REMARKS
1 F:\\Th?se\\R\\Doubs NA Faune$ SYSTEM TABLE NA
2 F:\\Th?se\\R\\Doubs NA Milieu$