Displaying 20 results from an estimated 1000 matches similar to: "Evaluate a function for various value of parameters"
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")
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)
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
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$
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
2005 Nov 11
1
A 'sweave' strange problem !!!
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,
2007 Sep 14
3
problems for ./configure on Ralpha: gcc related
Dear all,
I am trying to compile Ralpha on my computer (OS = Debian). SVN Revision is:
Revision: 42843
Last Changed Date: 2007-09-14
./configure returns :
----------------------------------------------------
stephane at pcdray:~/Rdev/R-alpha$ ./configure
checking build system type... i686-pc-linux-gnulibc1
checking host system type... i686-pc-linux-gnulibc1
loading site script
2001 Nov 06
2
Canonical Correspondence analysis-CoCoAn package
Hi R-users,
I am new to R environment.I want to carry out a
correspondence analysis on a contigency table with 64
columns and 298 observation of Environmental data.In
many cells of the contigency table the frequency is
just the value '1'.
I got the following error.
> CAIV(Eplankton)
Error in if (L[i, j] < 0) return("Table L must contain
non-negative numbers") :
2006 Nov 10
2
Simplifying Sweave graphics
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2008 Apr 22
4
Modeling presence only data in R
Dear All,
I have a set of environental maps and presence-only points for some species.
How can I generate distributions models on R using these presence-only data?
What packages and functions can I use to do so?
Kind regards,
Miltinho
Brazil
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2007 Mar 28
2
Standardization Range
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indicato...
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2004 Oct 01
1
cumsum over a list or an array
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))) #
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
2008 Feb 26
3
R package to perform Horn's parallel analysis
I am seeking information on whether anyone has written code to perform
Horn's parallel analysis (a procedure that informs the selection of the
proper number of components in PCA) in R.
Thank you in advance for any help you can provide. Please respond
off-list at the email address below.
Karen Douglas
*******************************************************************
Karen Douglas,
2009 Apr 03
1
Weighted principal components analysis?
Hello R-ers,
I'm trying to do a weighted principal components analysis. I couldn't find any such option with princomp or prcomp. Does anyone know of a package or way to do this?
More specifically, the observations I'm working with are averages from populations of varying sizes. I thus need to weight the observations by sample size. Ideally I could apply these weights at the cell
2001 Feb 16
12
canonical correspondence analysis
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
2008 Dec 11
2
Principal Component Analysis - Selecting components? + right choice?
Dear R gurus,
I have some climatic data for a region of the world. They are monthly averages
1950 -2000 of precipitation (12 months), minimum temperature (12 months),
maximum temperature (12 months). I have scaled them to 2 km x 2km cells, and
I have around 75,000 cells.
I need to feed them into a statistical model as co-variates, to use them to
predict a response variable.
The climatic
2007 Oct 16
2
Canberra distance
Hi,
I misunderstand the definition of Canberra distance in R.
On Internet and in function description pages of dist() from stats and
Dist() from amap, Canberra distance between vectors x and y, d(x,y), is :
d(x,y) = sum(abs(x-y)/(x+y))
But in use, through simple examples, we find that the formula is :
d(x,y) = (NZ + 1)/NZ * sum(abs(x-y)/(x+y))
with NZ = nb of pairs of coordinates that are
2003 Jan 14
3
PLS regression?
Hi all,
I would like to do some QSAR analysis (quantitative structure activity
relationship). I need to use some Partial Least Squares (PLS) regression,
but I have not seen this option on the R-project. Is it possible to do this
kind of regression on R?
thank you in advance
best regards,
olivier
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