Displaying 20 results from an estimated 500 matches similar to: "PCA R"
2005 Mar 14
1
Significance of Principal Coordinates
Dear all,
I was looking for methods in R that allow assessing the number of
significant principal coordinates. Unfortunatly I was not very
successful. I expanded my search to the web and Current Contents,
however, the information I found is very limited.
Therefore, I tried to write code for doing a randomization. I would
highly appriciate if somebody could comment on the following approach.
2009 Nov 15
1
Problem building package for R 2.10.0 on Mac OS X
Hi
I have submitted a package (rioja) to CRAN. It checks OK for all R versions and OS's except r-release-macosx-ix86 where it fails when checking the examples. Specifically, it fails because R can't find the package vegan which is needed in a function. Here is the snippet from the check results:
### Begin snippet
checking examples ... ERROR
Running examples in 'rioja-Ex.R'
2004 Jul 31
1
dudi.pca behaviour and discrimin
Hello,
I not have attached in this e-mail the zipped
list of matrices I am using because it has 1 meg
once zipped and anyway we cannot send attached
files on r-help mailling list.
First, after running the code that is written
bellow, I realized that the printout of dudi.pca
gives me for both of my matrices
$cw length that are unequal to either respective $rank or $eig lengths.
Is that
How to use PC1 of PCA and dim1 of MCA as a predictor in logistic regression model for data reduction
2011 Aug 17
4
How to use PC1 of PCA and dim1 of MCA as a predictor in logistic regression model for data reduction
Hi all,
I'm trying to do model reduction for logistic regression. I have 13
predictor (4 continuous variables and 9 binary variables). Using subject
matter knowledge, I selected 4 important variables. Regarding the rest 9
variables, I tried to perform data reduction by principal component
analysis (PCA). However, 8 of 9 variables were binary and only one
continuous. I transformed the data by
2006 Mar 13
0
Bootstrapping PCA + Standard Error Scree
Two questions about principal components analysis in R:
Q.1) Hogenraad and McKenzie (1999) used Bruce Thompson's FACSTRAP
program to bootstrap the factor loadings and scores in a principal
components analysis. The input to the analysis was a word-word
correlation matrix derived from a frequency count of x words across n
texts. This is how they described their procedure:
"Finally, we
2005 Jan 08
0
cmdscale problem
Dear R developers,
there appears to be a small problem with function cmdscale: for
non-Euclidean distance matrices, using option add=FALSE (the default),
cmdscale misses the smallest eigenvalue. This affects GOF statistic g.1
(See Mardia, Kent + Bibby (1979): Multivariate Analysis, eq. (14.4.7).
The corresponding formula in Cox + Cox (2001): Multidimensional Scaling,
2nd ed., p 38, would
2010 Feb 18
1
R-commands for MDS
Hello
I am using the following command but not able to text the values on the graph can
someone please make suggestions for improvement
#here is the command
loc_mds <- cmdscale(dist.r, k = 7, eig = TRUE)
loc_mds$eig
sum(abs(loc_mds$eig[1:2]))/sum(abs(loc_mds$eig))
sum((loc_mds$eig[1:2])^2)/sum((loc_mds$eig)^2)
x <-loc_mds$points[,1]
y <-loc_mds$points[,2]
plot(x, y,
2005 Dec 04
1
Understanding nonlinear optimization and Rosenbrock's banana valley function?
GENERAL REFERENCE ON NONLINEAR OPTIMIZATION?
What are your favorite references on nonlinear optimization? I like
Bates and Watts (1988) Nonlinear Regression Analysis and Its
Applications (Wiley), especially for its key insights regarding
parameter effects vs. intrinsic curvature. Before I spent time and
money on several of the refences cited on the help pages for "optim",
2009 Jan 24
1
Help with dudi.pca
Dear R-helpers,
I have two data frames, op and em4:
> str(op)
'data.frame': 37 obs. of 5 variables:
$ m : num 0.202 0.336 0.122 0.139 0.14 ...
$ lln : num 0.798 0.643 0.863 0.835 0.823 ...
$ rrn : num 0.789 0.702 0.894 0.895 0.923 ...
$ asym2: num 0.177 0.304 0.108 0.187 0.274 ...
$ asym3: num 0.0755 0.0975 0.0818 0.0651 0.13 ...
> str(rownames(op))
chr
2010 May 02
2
Scree diagram,
hello,
I've two questions today.
1) I'm trying to do a scree diagram, I did a Google for a specific command I
could used to do so. All I could find is a screeplot. Are they the same
command?
2) what command can I used to present a PC scores, eigenvectors of the PC
scores, and component correlations?
thanks!
--
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2003 May 06
2
R vs SPSS output for princomp
Hi,
I am using R to do a principal components analysis for a class
which is generally using SPSS - so some of my question relates to
SPSS output (and this might not be the right place). I have
scoured the mailing list and the web but can't get a feel for this.
It is annoying because they will be marking to the SPSS output.
Basically I'm getting different values for the component
2008 Jan 05
2
Cumulative sum of vector
Hi,
Maybe I have not been looking in the right spot, but, I have not been
able to fine a command to automatically calculate the running
cumulative sum of a vector. Is there such a command?
Example of current code:
> eig$values
[1] 678.365651 6.769697 2.853783
> prop<-eig$values/sum(eig$values)
> prop
[1] 0.986012163 0.009839832 0.004148005
>
2002 Jan 07
3
cluster - clusplot.default (PR#1249)
The following code in clusplot.default (package cluster) is in error:
x1 <- cmdscale(x, k = 2, eig = TRUE)
var.dec <- sum(x1$eig)/sum(diag(x1$x))
if (var.dec < 0)
var.dec <- 0
if (var.dec > 1)
var.dec <- 1
x1 <- x1$points
x1 has components with names "points" and "eig", not "x", so
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")
2008 Mar 03
1
Extracting data from Eigen function
Hi
I need to extract the data returned by Eigen to plot the eigenvectors.
However, when I try and eigv = eigen(covariance); it returns an object with
the matrices containing eigenvalues and vectors.. how can I extract the
eigenvector matrix from this??
When I try mat = eig["vectors"] it returns a matrix with the "$vectors"
string on top , how can I remove this?
code:
> eig
2003 Feb 06
6
Confused by SVD and Eigenvector Decomposition in PCA
Hey, All
In principal component analysis (PCA), we want to know how many percentage
the first principal component explain the total variances among the data.
Assume the data matrix X is zero-meaned, and
I used the following procedures:
C = covriance(X) %% calculate the covariance matrix;
[EVector,EValues]=eig(C) %%
L = diag(EValues) %%L is a column vector with eigenvalues as the elements
percent
2002 Mar 08
1
Matrix multiplication problem
Dear List,
I am having trouble with some R code I have written to perform
Redundancy Analysis (RDA) on a matrix of species abundance data (Y) and
a matrix of environmental data (X).
RDA is a constrained form of PCA and can be thought of as a PCA of the
fitted values of a regression of each variable in Y on all variables in
X.
For info, the first use of RDA is in:
Rao, C.R, 1964. The use and
2005 Jan 04
1
scree plot
Hi!
Is there an easy way to add to the scree-plot labels to each value pertaining to the cumulative proportion of explained variance?
Thanks and a happy new year
Anne
----------------------------------------------------
Anne Piotet
Tel: +41 79 359 83 32 (mobile)
Email: anne.piotet@m-td.com
---------------------------------------------------
M-TD Modelling and Technology Development
PSE-C
2005 Jul 25
1
Winbind and AD issues
Hello,
I've been working on integrating a Fedora Core 2 box into Active
Directory over the weekend.. it's a file server running Samba.
I seem to have partial success but it isn't really working how I want it
to and maybe some clever person here can see the problem.
I've joined it to the AD and I see the computer account in there..
Kerberos seems to work:
***************
2008 May 03
0
factor analysis for binary data with FactoMineR package
Hi List,
I'm following on the discussions regarding the use of exploratory factor analysis with binary data, from nabble:
http://www.nabble.com/PCA--for-Binary-data-to11050371.html#a11092127
and i tried using FactorMineR package but unfortunately i have trouble understanding what are the types of the variables which AFDM is suitable for? I guessed from that example in ?AFDM that