Displaying 20 results from an estimated 130 matches similar to: "Eigenvectors and values in R and SAS"
2003 Mar 26
1
Solving equations
Hello,
Does somebody knows if there exists a function which solves a set of
equation, say f(vars),
for the variables vars (similar to Solve in mathematica).
The functions I am considering are of the form f(t) ~ A*exp(B*t), where
A and B are matrices.
Thanks Thomas
2010 Nov 10
2
prcomp function
Hello,
I have a short question about the prcomp function. First I cite the
associated help page (help(prcomp)):
"Value:
...
SDEV the standard deviations of the principal components (i.e., the square
roots of the eigenvalues of the covariance/correlation matrix, though the
calculation is actually done with the singular values of the data matrix).
ROTATION the matrix of variable loadings
2010 Sep 29
1
Fitting a half-ellipse curve
Dear mailing list,
I have following array:
X2 Y2
[1,] 422.7900 6.0
[2,] 469.8007 10.5
[3,] 483.9428 11.0
[4,] 532.4917 25.5
[5,] 596.1942 33.5
[6,] 630.8496 40.5
[7,] 733.2996 45.0
[8,] 946.4779 32.0
[9,] 996.8068 35.5
[10,] 1074.3310 23.0
I do afterwards the following:
plot.new()
plot.window(xlim=c(min(X1)-50,max(X1)+50),
2007 Aug 12
1
Write values on y axe
Hi,
I have values on y axe from 0.0001 to 3.086. When I do plot I have writen
values: 0.001, 0.050,1.000 ..., but how I can write on graph the minimum
value and maximum value, with all decimals (I don't want to use the format
1e-0x)? I am using log scale.
For example, if I have the values:
0.0001
0.0015
0.0256
0.0236
....
0.0201
2.9668
3.0086
I need have each 'x' value put on y axe,
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",
2006 May 19
4
why no multiple submit?
is it by design? is it standard? how do you give users multiple
actions on a form?
--
Posted via http://www.ruby-forum.com/.
2002 Nov 26
3
dovecot and pop3
Dear dovecotters:
I'm becoming interested in dovecot as a replacement for UW-IMAPD. Any
project that claims it's the "postfix of ____ servers" deserves a looksee.
If indeed I were to going to switch at some point, I'd need to replace
the UW POP3 server (which is a part of the UW package). I would prefer
one that actually used the dovecot IMAP server instead of going to
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
2011 Jul 28
1
sorting data from dataframe with oter dataframe
Hi, the subject isn't define well the problem, so i'll explain it in detail:
i've got a csv.file with data on number of factors (every column got the
name
of the factor as header and the data below). on another csv file, i've got
the
factors sorted by their type. for example-
c1=read.csv('C:/R/c1.csv', header= TRUE)
urrDate A_XS b_XS c_XS
2023 Mar 11
3
Multiple Assignment built into the R Interpreter?
Dear R Core,
working on my dynamic factor modelling package, which requires several
subroutines to create and update several system matrices, I come back to
the issue of being annoyed by R not supporting multiple assignment out of
the box like Matlab, Python and julia. e.g. something like
A, C, Q, R = init_matrices(X, Y, Z)
would be a great addition to the language. I know there are several
2010 Mar 19
1
Howto get unnormalized eigenvectors?
Hi,
I try to calculate the angle between two first eigenvectors of different covariance matrices of biological phenotypic traits for different populations. My issue here is, that all possibilities to do so seem to normalize the eigenvectors to length 1. Although the helpfile of eigen() states, that using eigen(, symmetric = FALSE, EISPACK =TRUE) skips normalization this is (I guess) not applicable
2001 Sep 21
1
Request for Help: Rotation of PCA Solution or Eigenvectors
Dear R Helper,
I am writing because I seek to perform a varimax rotation
on my Principal Components Analysis (PCA) solution. (I have been
performing PCA's using the eigen command in R.) If you can tell me
how to perform this rotation when I use the eigen command (or the
princomp command) I would be thrilled.
Thanks so much!
Wendy Treynor
Ann Arbor, MI
USA
2004 Jun 22
0
prcomp & eigenvectors
I have the following situation I want to analyse with prcomp.
Each subject has a curve called the contrast sensitivity function (CSF).
This curve's overall shape is due to the additive output of 3 "channels"
(eigenvectors).
#this shows 3 SF channels; net CSF = c1 + c2+c3
x<-1:100
c1<-dnorm(x,mean=20,sd=20)
c2<-dnorm(x,mean=50,sd=20)
c3<-dnorm(x,mean=80,sd=20)
2003 Jun 09
1
understanding eigen(): getting non-normalized eigenvectors
Hi, dear R pros
I try to understand eigen(). I have seen, that eigen() gives the
eigenvectors normalized to unit length.
What shall I do to get the eigenvectors not normalized to unit length?
E.g. take the example:
A
[,1] [,2]
V1 0.7714286 -0.2571429
V2 -0.4224490 0.1408163
Calculating eigen(A) "by hand" gives the eigenvectors (example from
Backhaus,
2008 Jul 08
1
Help with eigenvectors
Hi everybody,
I have some problems with the function eigen. I have a square matrix and I
want to calculate the eigenvalues and eigenvectors. I apply the function
eigen and I get it, however when I solve the same problem in Statistica
software, I realise that some eigenvectors are the opposite. How can I get
the same values?
Thanks in advance
[[alternative HTML version deleted]]
2011 May 28
1
prcomp & eigenvectors ... ??
Hi ...
Please could you help with probably a very simple problem I have. I'm completely new to R and am trying to follow a tutorial using R for Force Distribution Analysis that I got from ... http://projects.eml.org/mbm/website/fda_gromacs.htm. Basically, the MDS I preform outputs a force matrix (.fm) from the force simulation I perform.
Then, this matrix is read into R and prcomp is
2010 Jun 15
1
Getting the eigenvectors for the dependent variables from principal components analysis
Dear listserv,
I am trying to perform a principal components analysis and create an output table of the eigenvalues for the dependent variables. What I want is to see which variables are driving each principal components axis, so I can make statements like, "PC1 mostly refers to seed size" or something like that.
For instance, if I try the example from ?prcomp
> prcomp(USArrests,
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
2013 Mar 14
2
Same eigenvalues but different eigenvectors using 'prcomp' and 'principal' commands
Dear all,
I've used the 'prcomp' command to
calculate the eigenvalues and eigenvectors of a matrix(gg).
Using the command 'principal' from the
'psych' packageĀ I've performed the same exercise. I got the same
eigenvalues but different eigenvectors. Is there any reason for that
difference?
Below are the steps I've followed:
1. PRCOMP
#defining the matrix
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,]