Displaying 20 results from an estimated 300 matches similar to: "nipals in the chemometrics package in R"
2008 May 01
4
efficient code - yet another question
Dear list members;
The code given below corresponds to the PCA-NIPALS (principal
component analysis) algorithm adapted from the nipals function in the
package chemometrics. The reason for using NIPALS instead of SVD is
the ability of this algorithm to handle missing values, but that's a
different story. I've been trying to find a way to improve (if
possible) the efficiency of the code,
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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2010 Sep 27
3
Howto compile chemometrics package from source
Dear friends,
I'm confused about how to install packages from source.
I just updated R in Lenny from http://cran.fiocruz.br/bin/linux/debian/
I included in sources.list:
deb http://cran.fiocruz.br/bin/linux/debian lenny-cran/
deb-src http://cran.fiocruz.br/bin/linux/debian lenny-cran/
Then:
apt-get update
apt-get install r-base r-base-dev
Then I downloaded the package
2005 Feb 18
3
Barplot - Can't figure it out
Hi,
I have two catagorical vectors like this;
x = c(1, 2, 4, 2, 1)
y = c(2, 4, 2 ,4, 1)
I want to set up a barplot with the catagories 1-4 horizontally and
number of occurances vertically for each vector x,y. I've tried
boxplot(table(x,y), beside=T)
and
boxplot(c(x,y), beside=T)
among others, but can't get it to work...Any ideas? I'd apppreciate any help
2003 Nov 01
1
Partial least squares.
Dear R-helpers,
I am looking, quite unsuccesfully, for a number of functions/packages.
Firstly, I am interested in a package for partial least squares. I have
found that there seemed to exist a package called pls, but which seems
not to run any more with modern versions of R. I have not been able to
find certain "chemometrics package" I found some people discussing about
in this
2002 Nov 02
2
Partial Least Squares
Hi everybody!
Is there any package or functions to make Partial Least Squares
analysis with R?
Thanks a lot
Luis
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2017 Dec 21
0
New package: nipals
I would like to announce the availability of the 'nipals' package on CRAN,
https://cran.r-project.org/web/packages/nipals/.
The nipals package tries to do just one thing really well...find principal
components of a matrix using Nonlinear Partial Least Squares. Missing
values are allowed, the principal components are orthogonal, and the code
has been heavily optimized.
Details of the
2017 Dec 21
0
New package: nipals
I would like to announce the availability of the 'nipals' package on CRAN,
https://cran.r-project.org/web/packages/nipals/.
The nipals package tries to do just one thing really well...find principal
components of a matrix using Nonlinear Partial Least Squares. Missing
values are allowed, the principal components are orthogonal, and the code
has been heavily optimized.
Details of the
2008 Sep 21
0
Task View for Chemometrics and Computational Physics
Dear All,
A new task view "ChemPhys" on chemometrics and computational physics is
available on CRAN (http://cran.r-project.org/web/views/ChemPhys.html).
It describes packages and functions that are of use in modeling
chemical/physical systems.
Suggestions and comments regarding this task view are welcome. If you
think a new category, package or function should be added, please mail.
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")
2003 Sep 02
0
R/Chemometrics/reading .spa files into R.
Maybe someone out there has done this already .... (which would save me some time):
For a repetitive chemometric task I need to retrieve spectra from a Nicolet IR acquisition system into R and analyze them there. The raw spectra are in files ending in the extension .spa. I can use the Omnic software to export them to .csv, but I would like to skip this step since it is manual. Has anyone of you
2013 Apr 07
3
mlogit error
Dear List
I am trying to fit a multinomial model using the mlogit package. Attempting to load
the data into mlogit presents the following error.
MLOG<-mlogit.data(Mult3,shape="long",choice="CHOICE",alt.var="mode.ids",indivs = "set3",chid.var = "obs")
Error in `row.names<-.data.frame`(`*tmp*`, value = c("1.1", "1.2",
2000 Oct 03
3
prcomp compared to SPAD
Hi !
I've used the example given in the documentation for the prcomp function
both in R and SPAD to compare the results obtained.
Surprisingly, I do not obtain the same results for the coordinates of
the principal composantes with these two softwares.
using USArrests data I obtain with R :
> summary(prcomp(USArrests))
Importance of components:
PC1 PC2
2017 Sep 18
1
Data arrangement for PLSDA using the ropls package
Hello,
I would like to do a partial least square discriminant analysis (PLSDA) in R using the package "ropls"
Which is in R available via the R command :
source("https://bioconductor.org/biocLite.R")
I try to do a PLSDA to illustrate the impact of two genders (AP,C) on 5 compounds measured in persons (samples) should be illustrated. When I try to do a PLSDA I get the warning
2009 Jun 13
2
How to write loop
Dear all,
I want to do the following process as a loop ( to run
automatically with dimension of X, here 50). How can I do that? Your
cooments will be highly appreciable.
Alex
*# Code:*
library(lars)
library(chemometrics)
X<-matrix(rnorm(2500),ncol=50)
dim(X)
# [1] 50 50
X1<-X[,2:dim(X)[2]] # I have taken out first column
dim(X1)
#[1] 50 49
X2<-X1[2:dim(X1)[1],] #
2004 Aug 20
3
Partial Least Squares
Friends,
Is there a Partial Least Squares package implemented in R?
Thanks,
Lana
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2011 Apr 20
4
Two Questions
Sorry for the somewhat nondescript subject line, but I have two questions:
1. What is a really good book on R for a nonprogrammer?
2. How do I open more than one R Graphics: Device 2(ACTIVE). That
what is the R command that I can use to keep more than one plot open. I am
running a script from a book on Chemometrics that results in more than one
graph during the execution, but
2013 Apr 23
2
Needed: Beta Testers and Summer Camp Students
Greetings.
I'm teaching linear regression this semester and that means I write
more functions for my regression support package "rockchalk". I'm at
a point now were some fresh eyes would help, so if you are a student
in a course on regression, please consider looking over my package
overview document here:
http://pj.freefaculty.org/R/rockchalk.pdf
That tells how you can grab
2009 Jan 21
2
Does anyone has this paper in pdf?
de Jong, S. (1993) SIMPLS: an alternative approach to partial least squares
regression. Chemometrics and Intelligent Laboratory Systems, 18, 251?263
Thanks
2013 Mar 18
1
Windows R-3.0.0 and Tcl/tkrplot issue
Greetings R Developers,
I've been testing the alpha release of R-3.0.0 and I noticed that the plotting functionality in package tkrplot was not working correctly.
Further diagnosis found the issue to be related to the command '.Tcl("image create Rplot plotname")' from package "tkrplot".
The following example is taken from here: