Displaying 20 results from an estimated 1000 matches similar to: "Solve an ordinary or generalized eigenvalue problem in R?"
2012 Apr 23
0
Solve an ordinary or generalized eigenvalue problem in R
This thread reveals that R has some holes in the solution of some of the linear algebra
problems that may arise. It looks like Jim Ramsay used a quick and dirty approach to the
generalized eigenproblem by using B^(-1) %*% A, which is usually not too successful due to
issues with condition of B and making a symmetric/Hermitian problem unsymmetric.
In short, the problem is stated as follows:
2005 Jun 16
2
Computing generalized eigenvalues
I need to compute generalized eigenvalues. The eigen function in base
doesn't do it and I can't find a package that does.
As I understand it, Lapack __can__ computer them
(http://www.netlib.org/lapack/lawn41/node111.html) and R can use
Lapack. If there is no function already, can I access Lapack from R
and use those routines directly?
Thank you,
Joshua Gilbert.
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
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
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
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]]
2005 Dec 14
2
suggestions for nls error: false convergence
Hi,
I'm trying to fit some data using a logistic function defined as
y ~ a * (1+m*exp(-x/tau)) / (1+n*exp(-x/tau)
My data is below:
x <- 1:100
y <- c(0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,1,1,1,2,2,2,2,2,3,4,4,4,5,
5,5,5,6,6,6,6,6,8,8,9,9,10,13,14,16,19,21,
24,28,33,40,42,44,50,54,69,70,93,96,110,127,127,141,157,169,
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]
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
2020 Oct 15
2
package(moments) issue
Hi all,
While running the anscombe.test in R, I'm getting an error of *Error in if
(pval > 1) pval <- 2 - pval : missing value where TRUE/FALSE needed* for a
few time series columns whereas for most of the series the function is
working fine. I have checked for those specific columns for missing values.
However, there is no NA/NAN value in the dataset.
I have also run kurtosis for
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
--
View this message in context: http://www.nabble.com/matlab-eigs-function-in-R-tp17619641p17619641.html
Sent from the R help mailing list
2023 Mar 01
1
Incorrect behavior of ks.test and psmirnov functions with exact=TRUE
HI,
I've noticed what I think is an incorrect behavior of stats::psmirnov
function and consequently of ks.test when run in an exact mode.
For example:
psmirnov(1, sizes=c(50, 50), z=1:100, two.sided = FALSE, lower.tail = F,
exact=TRUE)
produces 2.775558e-15
However, the exact value should be 1/combination(100, 50), which is
9.9e-30. While the absolute error is small, the relative error is
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
2020 Oct 15
0
package(moments) issue
moments::anscombe.test(x) does give errors when x has too few values or if
all the values in x are the same
> moments::anscombe.test(c(1,2,6))
Error in if (pval > 1) pval <- 2 - pval :
missing value where TRUE/FALSE needed
> moments::anscombe.test(c(2,2,2,2,2,2,2,2))
Error in if (pval > 1) pval <- 2 - pval :
missing value where TRUE/FALSE needed
You can use tryCatch() to
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
2020 Oct 15
2
package(moments) issue
Hi Bill,
Thanks for prompt reply and letting me know a way around it.
I have more than 1200 observations and not all the values are the same.
However, my data points are quite similar, for example,
0.079275, 0.078867, 0.070716 in millions and etc. I have run the data
without converting it to millions and I still get the same error
message. As I have kurtosis value, it should be fine for the
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",
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
2008 Mar 27
1
Significance of confidence intervals in the Non-Linear Least Squares Program.
I am using the non-linear least squares routine in "R" -- nls. I have a
dataset where the nls routine outputs tight confidence intervals on the
2 parameters I am solving for.
As a check on my results, I used the Python SciPy leastsq module on the
same data set and it yields the same answer as "R" for the
coefficients. However, what was somewhat surprising was the the