Displaying 20 results from an estimated 100 matches similar to: "About LU decomposition in R"
2010 Feb 02
1
how to use optim() or nlm() to solve three nonlinear equations
Dear all,
I just know how to solve an eaquation by using optim() or nlm(). But, now, I have three nonlinear equations,
how could we use optim() or nlm() to solve a system of nonlinear equations in R? Thank you so much.
Sincerely,
Joe
___________________________________________________
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2006 May 12
2
reusing routines
I've created some Splus code for a microarray problem that
- needed to be in C, to take advantage of some sparse matrix
properties
- uses a cholesky decompostion as part of the computation
For the cholesky, I used the cholesky2 routine, which is a part of the
survival library. It does just what I want and I'm familiar with it (after
all, I wrote it).
In Splus, this all works
2010 Jul 26
1
O/T good c/c++ code for LU decomposition
Dear R People:
Could someone recommend a good c/c++ code (or Fortran) for LU
decomposition, please?
Sorry to bother about this. I'm trying to do some "non-R" work that
requires a matrix inversion.
Thanks,
Erin
--
Erin Hodgess
Associate Professor
Department of Computer and Mathematical Sciences
University of Houston - Downtown
mailto: erinm.hodgess at gmail.com
2011 Dec 16
0
Rd error message
I get the following error from one of my Rd files in R CMD check (R
2-14.0)
* checking Rd files ... WARNING
Error in switch(attr(block, "Rd_tag"), TEXT = if (!grepl("^[[:space:]]*
$", :
EXPR must be a length 1 vector
problem found in ?backsolve.Rd?
This is likely something that will be glaringly obvious once it's
pointed out, but without a line number I can't
2005 Jan 21
1
Cholesky Decomposition
Can we do Cholesky Decompositon in R for any matrix
---------------------------------
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2009 Mar 10
5
Cholesky Decomposition in R
Hi everyone:
I try to use r to do the Cholesky Decomposition,which is A=LDL',so far I
only found how to decomposite A in to LL' by using chol(A),the function
Cholesky(A) doesnt work,any one know other command to decomposte A in to
LDL'
My r code is:
library(Matrix)
A=matrix(c(1,1,1,1,5,5,1,5,14),nrow=3)
> chol(A)
[,1] [,2] [,3]
[1,] 1 1 1
[2,] 0 2 2
2007 Jun 04
2
rq matrix decomposition
I specifically need rq matrix decomposition (and not qr).
Looking at netlib site for LAPACK it does provide rq whereas LINPACK not.
Looking at companion qr in R I see how in base it wraps with a .Call but I
do not have success in doing that for a similar .Call for rq.
Anyone done this or can provide matrix rewrites that allow me to do the rq
decomposition with existing R funcs?
Regards MJ
2004 Aug 09
0
e164.lu
Hello,
we have set up e164.lu as a test zone, as the
delegation for 2.5.3.e164.arpa hasn't been
completed yet. For all those who want to call the
numbers currently availble directly via SIP,
please use the zone name in your enum.conf.
If you decide to use the zone, please tell me at
mstorck@luxadmin.org, so as soon as the
2.5.3.e164.arpa zone is ready, I will mail you, so
you may disable
2008 Jul 09
1
Question regarding lu in package Matrix
Dear R-helpers,
I have a question regarding LU-decomposition with function lu in package
Matrix. The following simple example confuses me: Why is as.matrix(elu$U)
not an upper triangular matrix?
u3 <-
matrix(c(1,1,1,1,1,1,-1,1,0,0,0,0,0,-1,1,0,0,0,-1,0,1,0,0,0,0,0,-1,1,0,0),5,6,byrow=T)
elu <- expand(lu(Matrix(u3,sparse=F)))
as.matrix(elu$U)
I only have very limited experience with the
2010 Jan 09
0
Activity after LU with ZFS/Zone working
Hy all,
recently I upgraded to S10U8 a T5120 using LU. The system had a zones
configured and at time of upgrade procedure the zones was still alive
and worked fine. The LU procedure was ended successfully. Zones on the
system was installed in a ZFS filesystem. Here the result at the end
of LU (ABE-from: s10Aug2007, ABE-to: s10Set2009):
# zfs list
NAME
USED AVAIL REFER MOUNTPOINT
2006 Dec 28
1
LU bug in Matrix package
There is a bug in Matrix package, please check it, thanks!
Matlab result:
x =
1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
16 17 18 19 20
21 22 23 24 25
>> lu(x)
ans =
21.0000 22.0000 23.0000 24.0000 25.0000
0.0476 0.9524 1.9048 2.8571 3.8095
0.7619
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
2012 Feb 21
1
System is computationally singular error when using cholesky decompostion in MCMC
Hello Everyone
I have a MCMC loop to calculate a time varying hierarchical Bayesian
structure.
This requires me to use around 5-6 matrix inversions in the loop.
I use cholesky and chol2inv for the matrix decomposition.
Because of the data I am working with I am required to invert a 167 by 167
matrix twice in one iteration.
I need to run the iteration for 10000 times, but I get the error
2008 Dec 09
2
Better way to find distances between points in a set?
I was playing around a bit to see how I could find the two points in a
set of points (or ordered pairs) furthest from each other.
Here's what I did:
1) created a Nrow by 2col matrix, so each row contains an x,y coordinate
pair.
2) fed the matrix to a nested mapply (cv is my matrix):
mapply(function(k,l) mapply(function(x,y,a,b)
+
2008 Dec 22
2
How can I avoid nested 'for' loops or quicken the process?
Hi All,
I'm still pretty new to using R - and I was hoping I might be able to get
some advice as to how to use 'apply' or a similar function instead of using
nested for loops.
Right now I have a script which uses nested for loops similar to this:
i <- 1
for(a in Alpha) { for (b in Beta) { for (c in Gamma) { for (d in Delta) {
for (e in Epsilon)
{
Output[i] <-
2010 Feb 04
1
Retrieve estimates from glmer()
Dear all,
I am running glmer() in R. How can I retrieve the estimates of fixed effects and the variance of the random effects from the result? Thank you so much.
Joe
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2010 Jul 13
1
A problem about the package "lme4" in R-2.11.1
Dear all R-users,
When I install the package "lme4" in R-2.11.1, and use it to run the
simulation on the Linux system, it appears the following problem.
Attaching package: 'lme4'
The following object(s) are masked from 'package:stats':
AIC
Error in names(argNew)[1] <- names(formals(new))[[1]] :
replacement has length zero
Calls: initial ... lmerFactorList
2008 Feb 01
3
Phase Shift
Is there any implementation in R for finding the phase shift between
two continuous signals. I would like to find the average phase shift
for tow signals over two years.
thanks
Stephen
--
Let's not spend our time and resources thinking about things that are
so little or so large that all they really do for us is puff us up and
make us feel like gods. We are mammals, and have not exhausted
2008 Nov 14
1
configuring graphics device in Linux
greetings,
i'm trying plot() from Owen's _The R Guide_ and having trouble with
being able to view the result. the Graphics Device 2 draws an image i
can only see the top part of and when i try to manipulate the window to
see the image, the window then says: "...ure margins too lar..." in
large letters. i guess it says something about picture margins too
large. i'm not sure
2000 Mar 21
2
chol2inv question
Hi there,
Please help me this out.
> m
[,1] [,2]
[1,] 1.1 1.0
[2,] 1.0 1.1
> chol2inv(m)
[,1] [,2]
[1,] 1.5094597 -0.7513148
[2,] -0.7513148 0.8264463
>
CT
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