Displaying 20 results from an estimated 4000 matches similar to: "storing data from loops"
2008 Jun 03
3
matlab eigs function in R
Hello
Does anybody know how one can compute d largest eigenvalues/eigenvectors in
R, like in MATLAB eigs function ? eigen function computes all
eigenvectors/eigenvalues, and they are slightly different than those
generated by matlab eigs.
Thanks in advance
--
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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
2004 Apr 19
0
R analog of Matlab "eigs" function
Hi,
I was wondering if anyone knew of an implementation of a function similar to
"eigs" in Matlab (full description here:
http://www.mathworks.com/access/helpdesk/help/techdoc/ref/eigs.html).
This function differs from the standard "eigen" in that it computes a *few*
eigenvectors for cases in which your matrix is very large and/or you don't
need all the eigenvectors.
2010 Jan 11
3
Eigenvectors and values in R and SAS
Hi,
I was wondering if function eigen() does something different from the
function call eigen() in SAS.
I'm in the process of translating a SAS code into a R code and the values of
the eigenvectors and eigenvalues of a square matrix came out to be different
from the values in SAS.
I would also appreciate it if someone can explain the difference in simple
terms. I'm pretty new to both
2011 Nov 14
0
Fwd: How to compute eigenvectors and eigenvalues?
Inicio del mensaje reenviado:
> De: Arnau Mir <arnau.mir@uib.es>
> Fecha: 14 de noviembre de 2011 13:24:31 GMT+01:00
> Para: Martin Maechler <maechler@stat.math.ethz.ch>
> Asunto: Re: [R] How to compute eigenvectors and eigenvalues?
>
> Sorry, but I can't explain very well.
>
>
> The matrix 4*mp is:
>
> 4*mp
> [,1] [,2] [,3]
> [1,]
2009 Apr 24
1
the puzzle of eigenvector and eigenvalue
Dear all
I am so glad the R can provide the efficient calculate about
eigenvector and eigenvalue.
However, i have some puzzle about the procedure of eigen.
Fristly, what kind of procedue does the R utilize such that the eigen
are obtained?
For example, A=matrix(c(1,2,4,3),2,2)
we can define the eigenvalue lamda, such as
det | 1-lamda 4 | =0
| 2 3-lamda |
then
2009 Dec 01
1
eigenvalues of complex matrices
Dear all,
I want to compute the eigenvalues of a complex matrix for some statistics.
Comparing it to its matlab/octave sibling, I don't get the same eigenvalues
in R computing it from the exact same matrix.
In R, I used eigen() and arpack() that give different eigenvalues. In
matlab/octave I used eig() and eigs() that give out the same eigenvalues but
different to the R ones.
For real
2010 Jun 25
2
Forcing scalar multiplication.
I am trying to check the results from an Eigen decomposition and I need to force a scalar multiplication. The fundamental equation is: Ax = lx. Where 'l' is the eigen value and x is the eigen vector corresponding to the eigenvalue. 'R' returns the eigenvalues as a vector (e <- eigen(A); e$values). So in order to 'check' the result I would multiply the eigenvalues
2006 Mar 13
0
wishlist: function mlh.mlm to test multivariate linear hypotheses of the form: LBT'=0 (PR#8680)
Full_Name: Yves Rosseel
Version: 2.2.1
OS:
Submission from: (NULL) (157.193.116.152)
The code below sketches a possible implementation of a function 'mlh.mlm' which
I think would be a good complement to the 'anova.mlm' function in the stats
package. It tests a single linear hypothesis of the form H_0: LBT'= 0 where B is
the matrix of regression coefficients; L is a matrix
2007 Nov 27
0
Function to calculate eigenvector bootstrap error
Hi everybody,
I need help in writing a statistical function for bootstrap. Suppose m is a matrix with n cols and p rows, my original data. What I want to do is a bootstrap (using boot from package boot) on eigenvectors from a PCA done on m with a statistic function calculating the eigenvector bootstrap error ratio.
If R = number of bootstrap replicates, then my function should look something
2009 Apr 23
1
the definition of eigenvector in R
Dear All
i have a little puzzle about eigenvector in the R.
As we know that the eigenvector can be displayed on several form.
For example
A=matrix(c(1,2,4,3),2,2)
if we want to get the eigenvalue and eigenvector, the code followed
eigen(A)
$values
[1] 5 -1
$vectors
[,1] [,2]
[1,] -0.7071068 -0.8944272
[2,] -0.7071068 0.4472136
however, we also can calculate the vector matrix
2012 Apr 27
2
find the eigenvector corresponding to the largest eigenvalue
Hi,
If I use the eigen() function to find the eigenvalues of a matrix, how can I find the eigenvector corresponding to the largest eigen value?
Thanks!
[[alternative HTML version deleted]]
2012 Sep 25
1
REML - quasipoisson
hi
I'm puzzled as to the relation between the REML score computed by gam and
the formula (4) on p.4 here:
http://opus.bath.ac.uk/22707/1/Wood_JRSSB_2011_73_1_3.pdf
I'm ok with this for poisson, or for quasipoisson when phi=1.
However, when phi differs from 1, I'm stuck.
#simulate some data
library(mgcv)
set.seed(1)
x1<-runif(500)
x2<-rnorm(500)
2012 Oct 01
0
[Fwd: REML - quasipoisson]
Hi Greg,
For quasi families I've used extended quasi-likelihood (see Mccullagh
and Nelder, Generalized Linear Models 2nd ed, section 9.6) in place of
the likelihood/quasi-likelihood in the expression for the (RE)ML score.
I hadn't realised that this was possible before the paper was published.
best,
Simon
ps. sorry for slow reply, the original message slipped through my filter
for
2003 Apr 03
2
Matrix eigenvectors in R and MatLab
Dear R-listers
Is there anyone who knows why I get different eigenvectors when I run
MatLab and R? I run both programs in Windows Me. Can I make R to produce
the same vectors as MatLab?
#R Matrix
PA9900<-c(11/24 ,10/53 ,0/1 ,0/1 ,29/43 ,1/24 ,27/53 ,0/1 ,0/1 ,13/43
,14/24 ,178/53 ,146/244 ,17/23 ,15/43 ,2/24 ,4/53 ,0/1 ,2/23 ,2/43 ,4/24
,58/53 ,26/244 ,0/1 ,5/43)
#R-syntax
2012 Apr 25
1
pca biplot.princomp has a bug?
x=rmvnorm(2000, rep(0, 6), diag(c(5, rep(1,5))))
x=scale(x, center=T, scale=F)
pc <- princomp(x)
biplot(pc)
There are a bunch of red arrows plotted, what do they mean? I knew that the
first arrow labelled with "Var1" should be pointing the most varying
direction of the data-set (if we think them as 2000 data points, each being
a vector of size 6). I also read from
1997 May 01
0
R-alpha: eigen()
eigen() seems to work for symmetric matrices only. This is out of sync
with the help file.
> trpr.37
0 1 2 3 4
0 1.00000000 0.0000000 0.0000000 0.0000000 0.0000000
1 0.44444444 0.5555556 0.0000000 0.0000000 0.0000000
2 0.02439024 0.2439024 0.7317073 0.0000000 0.0000000
3 0.00000000 0.0000000 0.2307692 0.7692308 0.0000000
4 0.00000000 0.0000000
2007 Jun 29
4
Dominant eigenvector displayed as third (Marco Visser)
Dear R users & Experts,
This is just a curiousity, I was wondering why the dominant eigenvetor and eigenvalue
of the following matrix is given as the third. I guess this could complicate automatic selection
procedures.
0 0 0 0 0 5
1 0 0 0 0 0
0 1 0 0 0 0
0 0 1 0 0 0
0 0 0 1 0 0
0 0 0 0 1 0
Please
2005 Jul 04
0
eigen of a real pd symmetric matrix gives NaNs in $vector (PR#7989)
I would presume this is another manifestation of what I reported
(reproduced below) on 2003-12-01.
cajo.terbraak at wur.nl wrote:
>Full_Name: cajo ter Braak
>Version: 2.1.1
>OS: Windows
>Submission from: (NULL) (137.224.10.105)
>
>
># I would like to attach the matrix C in the Rdata file; it is 50x50 and comes
>from a geostatistical problem (spherical covariogram)
>
2006 Mar 03
1
NA in eigen()
Hi,
I am using eigen to get an eigen decomposition of a square, symmetric
matrix. For some reason, I am getting a column in my eigen vectors (the
52nd column out of 601) that is a column of all NAs. I am using the option,
symmetric=T for eigen. I just discovered that I do not get this behavior
when I use the option EISPACK=T. With EISPACK=T, the 52nd eigenvector is
(up to rounding error) a