Displaying 20 results from an estimated 10000 matches similar to: "Forcing scalar multiplication."
2011 Nov 14
2
How to compute eigenvectors and eigenvalues?
Hello.
Consider the following matrix:
mp <- matrix(c(0,1/4,1/4,3/4,0,1/4,1/4,3/4,1/2),3,3,byrow=T)
> mp
[,1] [,2] [,3]
[1,] 0.00 0.25 0.25
[2,] 0.75 0.00 0.25
[3,] 0.25 0.75 0.50
The eigenvectors of the previous matrix are 1, 0.25 and 0.25 and it is not a diagonalizable matrix.
When you try to find the eigenvalues and eigenvectors with R, R responses:
> eigen(mp)
$values
[1]
2008 Jun 18
2
highest eigenvalues of a matrix
DeaR list,
I happily use eigen() to compute the eigenvalues and eigenvectors of
a fairly large matrix (200x200, say), but it seems over-killed as its
rank is limited to typically 2 or 3. I sort of remember being taught
that numerical techniques can find iteratively decreasing eigenvalues
and corresponding orthogonal eigenvectors, which would provide a nice
alternative (once I have the
2009 Apr 24
1
the puzzle of eigenvector and eigenvalue
Dear all
I am so glad the R can provide the efficient calculate about
eigenvector and eigenvalue.
However, i have some puzzle about the procedure of eigen.
Fristly, what kind of procedue does the R utilize such that the eigen
are obtained?
For example, A=matrix(c(1,2,4,3),2,2)
we can define the eigenvalue lamda, such as
det | 1-lamda 4 | =0
| 2 3-lamda |
then
2006 Mar 03
1
NA in eigen()
Hi,
I am using eigen to get an eigen decomposition of a square, symmetric
matrix. For some reason, I am getting a column in my eigen vectors (the
52nd column out of 601) that is a column of all NAs. I am using the option,
symmetric=T for eigen. I just discovered that I do not get this behavior
when I use the option EISPACK=T. With EISPACK=T, the 52nd eigenvector is
(up to rounding error) a
2012 Apr 27
2
find the eigenvector corresponding to the largest eigenvalue
Hi,
If I use the eigen() function to find the eigenvalues of a matrix, how can I find the eigenvector corresponding to the largest eigen value?
Thanks!
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2004 Oct 19
3
matrix of eigenvalues
I thought that the function
eigen(A)
will return a matrix with eigenvectors that are independent of each
other (thus forming a base and the matrix being invertible). This
seems not to be the case in the following example
A=matrix(c(1,2,0,1),nrow=2,byrow=T)
eigen(A) ->ev
solve(ev$vectors)
note that I try to get the upper triangular form with eigenvalues on
the diagonal and (possibly) 1 just
2006 Aug 10
3
Geometrical Interpretation of Eigen value and Eigen vector
Dear all,
It is not a R related problem rather than statistical/mathematical. However
I am posting this query hoping that anyone can help me on this matter. My
problem is to get the Geometrical Interpretation of Eigen value and Eigen
vector of any square matrix. Can anyone give me a light on it?
Thanks and regards,
Arun
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2007 Jun 29
2
Spectral Decomposition
All of my resources for numerical analysis show that the spectral
decomposition is
A = CBC'
Where C are the eigenvectors and B is a diagonal matrix of eigen values.
Now, using the eigen function in R
# Original matrix
aa <- matrix(c(1,-1,-1,1), ncol=2)
ss <- eigen(aa)
# This results yields back the original matrix according to the formula
above
ss$vectors %*% diag(ss$values) %*%
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
2006 Jan 18
1
function 'eigen' (PR#8503)
Full_Name: Pierre Legendre
Version: 2.1.1
OS: Mac OSX 10.4.3
Submission from: (NULL) (132.204.120.81)
I am reporting the mis-behaviour of the function 'eigen' in 'base', for the
following input matrix:
A <- matrix(c(2,3,4,-1,3,1,1,-2,0),3,3)
eigen(A)
I obtain the following results, which are incorrect for eigenvalues and
eigenvectors 2 and 3 (incorrect imaginary portions):
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
2002 Nov 05
2
eigenvectors order
Hi,
How the eigenvectors output by the eigen() function are ordered. The
first column corresponds to the largest eigenvalue? or is the last
column as in Octave?
I'm performing a spatial-temporal analysis of some climatic variables
so my matrices are MxN (locations*time)and I'm looking for the leading
EOF's. As I have understand the eigenvectors columns represent those
EOF's
2004 Apr 15
5
Solving Matrices
On April 15th, Elizabeth wrote:
<snip>
> In execises 39-42, determine if the columns of the matrix span
> R4:
<snip>
>(or x <- matrix(data=c(7, -5, 6, -7, 2, -3, 10, 9, -5,
> 4, -2, 2, 8, -9, 7, 15), nrow=4, ncol=4)
>
>That is the whole of the question <snip>
Have you tried det(x) and/or eigen(x) ?
A zero determinant (within
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
2012 Apr 19
3
Solve an ordinary or generalized eigenvalue problem in R?
Folks:
I'm trying to port some code from python over to R, and I'm running into a
wall finding R code that can solve a generalized eigenvalue problem
following this function model:
http://docs.scipy.org/doc/scipy/reference/generated/scipy.linalg.eig.html
Any ideas? I don't want to call python from within R for various reasons,
I'd prefer a "native" R solution if one
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
2006 Mar 28
2
R crashes during 'eigen'
Hi all,
Hi,
When I want to compute the eigenvalues & eigenvectors of a specific
matrix, R crashes (i.e. it stops responding to any input). I've tried it
with different versions of R (2.1.1, 2.2.0, 2.2.1) - all with crashing
as result.
What I did before the crash was:
M <- as.matrix(read.table("thematrix",header=T))
eigen(M)
If, instead of eigen(M), I use eigen(M,
1997 May 18
2
R-alpha: Eigenvalue Computation Query
I have been looking at the "eigen" function and have reintroduced the
ability to compute (right) eigenvalues and vectors for non-symmetric
matrices. I've also made "eigen" complex capable.
The code is based on the eispack entry points RS, RG, CH, CG (which is
what S appears to use too). The problem with both the S and R
implementations is that they consume huge amounts
2012 Mar 09
1
Eigenvalue calculation of sparse matrices
Dear all,
I am currently working on the calculation of eigenvalues (and -vectors)
of large matrices. Since these are mostly sparse matrices and I remember
some specific functionalities in MATLAB for sparse matrices, I started a
research how to optimize the calculation of eigenvalues of a sparse matrix.
The function eigen itself works with the LAPACK library which has no
special handling for
2003 Apr 11
2
princomp with not non-negative definite correlation matrix
$ R --version
R 1.6.1 (2002-11-01).
So I would like to perform principal components analysis on a 16X16
correlation matrix, [princomp(cov.mat=x) where x is correlation matrix],
the problem is princomp complains that it is not non-negative definite.
I called eigen() on the correlation matrix and found that one of the
eigenvectors is close to zero & negative (-0.001832311). Is there any
way