Displaying 20 results from an estimated 5000 matches similar to: "symmetric matrix multiplication"
2011 Oct 23
0
FW: Re: symmetric matrix multiplication
Just to avoid possible confusion, let me correct a typo
(at step [2] in the example below). Apologies!
-----FW: <XFMail.111023084327.ted.harding at wlandres.net>-----
Date: Sun, 23 Oct 2011 08:43:27 +0100 (BST)
Sender: r-help-bounces at r-project.org
From: (Ted Harding) <ted.harding at wlandres.net>
To: r-help at r-project.org
Subject: Re: [R] symmetric matrix multiplication
On
2005 Jul 04
1
eigen of a real pd symmetric matrix gives NaNs in $vector (PR#7987)
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)
> rm(list=ls(all=TRUE))
> load(file= "test.eigen.Rdata")
> ls()
[1] "C" "eW"
>
> sym.check = max(abs(C - t(C))) # should
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)
>
2012 Mar 19
2
hypergeometric function in ‘ mvtnorm’
Is there any way to know how the "dmvt" function computes the hypergeometric
function needed in the calculation for the density of multivariate t
distribution?
--
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2013 Jun 18
1
eigen(symmetric=TRUE) for complex matrices
R-3.0.1 rev 62743, binary downloaded from CRAN just now; macosx 10.8.3
Hello,
eigen(symmetric=TRUE) behaves strangely when given complex matrices.
The following two lines define 'A', a 100x100 (real) symmetric matrix
which theoretical considerations [Bochner's theorem] show to be positive
definite:
jj <- matrix(0,100,100)
A <- exp(-0.1*(row(jj)-col(jj))^2)
A's being
2011 Mar 27
1
pmt
I am working with the pmt function in the {mnormt} package, and i am getting
negative values returned. the following is an example of one of my outputs:
pmt(x = c(3.024960, -1.010898), mean = c(21.18844, 21.18844), S =
matrix(c(.319,.139,.139,0.319), 2, 2),df = 42)
# -6.585641e-18
Any help on why i'm getting negative numbers would be very much appreciated.
THanks!
--
View this message in
2011 Dec 22
1
try to silence errors
I am trying to use the dmt function in the package {mnormt}. Throughout my
algorithm, the covariance matrix is sometime calculated to be singular.
When attempting to calculate the dmt function with a covariance that is not
positive definite, I would like it to return Inf or NaN instead of an error
message.
I have been using the try function, however it is not yeilding the desired
result. (I did
2007 Nov 29
1
?eigen documentation suggestion
from ?eigen
symmetric: if 'TRUE', the matrix is assumed to be symmetric (or
Hermitian if complex) and only its lower triangle is used. If
'symmetric' is not specified, the matrix is inspected for
symmetry.
I think that could mislead a naive reader as it suggests that, with symmetric=TRUE,
the result of eigen() (vectors and values) depends only on
2009 Jul 23
2
SystemFit
Hi,
I have two products which are substitudes. I try to fix a system as below to
mydata.
Demand1 = A1 -B1*Price1 + C1*Price2
Demand2 = A2 +B2*Price1 - C2*Price2
I would expect C1 & B2 to be symmetric, If they are truly substitude. How
can I enforce this symmetry when creating a system of equations via
SystemFit ?
--
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2011 Nov 16
2
Conversion of symmetry matrix into a vector
Dear R users,
I am not good in R-language programming. So, i need your help.
I want to convert my lower-triangle value of symmetry matrix into a vector with their row and column name.
I found a function called "sm2vec" in "corpcor" package but it give only a vector of values but not row and column names. But i also want ROW and COLUMN name together with their corresponding
2007 Mar 16
1
error code 5 from Lapack routine 'dsyevr'
While using the rmvnorm function, I get the error:
Error in eigen(sigma, sym = TRUE) : error code 5 from Lapack routine
'dsyevr'
The same thing happens when I try the eigen() function on my covariance
matrix. The matrix is a symmetric 111x111 matrix. Well, it is almost
symmetric; there are slight deviations from symmetry (the largest is
3e-18). I have this in an MCMC loop, and it
2006 Sep 23
1
variance-covariance structure of random effects in lme
Dear R users,
I have a question about the patterned variance-covariance structure for the random effects in linear mixed effect model.
I am reading section 4.2.2 of "Mixed-Effects Models in S and S-Plus" by Jose Pinheiro and Douglas Bates.
There is an example of defining a compound symmetry variance-covariance structure for the random effects in a
split-plot experiment on varieties of
2003 Jul 10
1
The question is on Symmetry model for square table.
Please help,
I tried a program on S-plus, and it worked. Also I tried the same
program on R but not worked. Here is the programme. I put it in a
function form. The model and assumption are at the bottom.
where
counts<-c(22,2,2,0,5,7,14,0,0,2,36,0,0,1,17,10)
which is name.data, i is row size and j is the column size.
symmetry
function(i, j, name.data)
{
row <- (c(1:i))
col <-
2003 Nov 04
2
real eigenvectors
Hello list,
Sorry, these questions are not directly linked to R.
If I consider an indefinte real matrix, I would like to know if the
symmetry of the matrix is sufficient to say that their eigenvectors are real ?
And what is the conditions to ensure that eigenvectors are real in the case
of an asymmetric matrix (if some conditions exist)?
Thanks in Advance,
St?phane DRAY
2009 Oct 12
1
unexpected behaviour of isSymmetric() (PR#14000)
Full_Name: Mike Danilov
Version: 2.9.0
OS: Fedora Core 9
Submission from: (NULL) (142.103.121.198)
When checking for the symmetry of a matrix, function isSymmetric.matrix() gets
confused by the discrepancy of colnames/rownames if its argument. See the code
snippet below. Perhaps it's a problem of the matrix product which copies
colnames of the first argument but not the rownames of the
2011 Sep 12
2
1 not equal to 1, and rep command
Hi
I need to use rep() to get a vector out, but I have spotted something very
strange. See the reproducible example below.
N <- 79
seg <- 5
segN <- N / seg # = 15.8
d1 <- seg - ( segN - floor(segN) ) * seg
d1 # = 1
rep(2, d1) # = numeric(0), strange - why doesn't it print one "2"?
rep(2, 1) # 2, ok
rep(2, d1 / 1,1) # 2, this
2003 Jul 03
2
SVD and spectral decompositions of a hermitian matrix
Hi:
I create a hermitian matrix and then perform its singular value
decomposition. But when I put it back, I don't get the original
hermitian matrix. I am having the same problem with spectral value
decomposition as well.
I am using R 1.7.0 on Windows. Here is my code:
X <- matrix(rnorm(16)+1i*rnorm(16),4)
X <- X + t(X)
X[upper.tri(X)] <- Conj(X[upper.tri(X)])
Y <-
2006 Jun 15
2
Problem on Matrix multiplication
Dear all r-users,
I am getting a big problem with matrix multiplication
suppose I have,
> weight
Weight
1 1067640
2 8871500
3 42948778
4 127583735
5 22000000
6 44000000
7 56850000
8 23805662
and,
> s
a b c d e
f g h
a 402493.18 -133931.62 461483.3 -94042.86 674493.8
2011 Feb 04
2
always about positive definite matrix
1. Martin Maechler's comments should be taken as replacements
for anything I wrote where appropriate. Any apparent conflict is a
result of his superior knowledge.
2. 'eigen' returns the eigenvalue decomposition assuming the
matrix is symmetric, ignoring anything in m[upper.tri(m)].
3. The basic idea behind both posdefify and nearPD is to compute
the
2014 Feb 05
2
[LLVMdev] SCEV implementation and limitations, do we need "pow"?
Hi,
I was looking at some bugs to play with, and I started with
http://llvm.org/bugs/show_bug.cgi?id=18606
As I commented there, a loop is unrolled and exhibit this pattern:
%mul.1 = mul i32 %mul, %mul
%mul.2 = mul i32 %mul.1, %mul.1
....
With an unroll factor of 32, the last multiply has 2^32 terms in its
SCEV expression.
(I mean I expect it would have those terms if I was patient