Displaying 20 results from an estimated 1000 matches similar to: "efficiently multiply different matrices in 3-d array with different vectors?"
2012 Nov 29
1
instrumental variables regression using ivreg (AER) or tsls (sem)
Dear friends,
I am trying to understand and implement instrumental variables
regression using R.
I found a small (simple) example here which purportedly illustrates the
mechanics (using 2-stage least-squares):
http://www.r-bloggers.com/a-simple-instrumental-variables-problem/
Basically, here are the R commands (reproducible example) from that
site:
# ------ begin R
library(AER)
2010 Sep 21
1
missing package tensorA
Hi: I was trying to download the package MCMCglmm and it give me this message:
Aviso: dependency ?tensorA? is not available
probando la URL
'http://www.vps.fmvz.usp.br/CRAN/bin/windows64/contrib/2.11/MCMCglmm_2.06.zip'
Content type 'application/zip' length 8988896 bytes (8.6 Mb)
URL abierta
downloaded 8.6 Mb
package 'MCMCglmm' successfully unpacked and MD5 sums checked
my
2008 Jul 29
1
tensor product of equi-spaced B-splines in the unit square
Dear all,
I need to compute tensor product of B-spline defined over equi-spaced
break-points.
I wrote my own program (it works in a 2-dimensional setting)
library(splines)
# set the break-points
Knots = seq(-1,1,length=10)
# number of splines
M = (length(Knots)-4)^2
# short cut to splineDesign function
bspline = function(x) splineDesign(Knots,x,outer.ok = T)
# bivariate tensor product of
2025 May 20
2
how to read a PSB file in R?
On Tue May20'25 05:56:59AM, Rui Barradas wrote:
> From: Rui Barradas <ruipbarradas at sapo.pt>
> Date: Tue, 20 May 2025 05:56:59 +0100
> To: Ranjan Maitra <mlmaitra at gmx.com>, r-help at r-project.org
> Subject: Re: [R] how to read a PSB file in R?
>
> ?s 03:17 de 20/05/2025, Ranjan Maitra via R-help escreveu:
> > I have come across this file (warning,
2008 Dec 03
1
Taking slices with tensorA
I've set up a simple tensor with indices 'a' and 'b'.
> ftable(B)
b u v w x y
a
a1 0.001868954 0.403345197 0.030088185 0.137252368 0.142634612
a2 0.396935972 0.945219795 0.068828465 0.314180585 0.446338719
a3 0.752412200 0.748810918 0.125532631 0.471686930 0.345062348
a4 0.191103000 0.536607533 0.257740399
2001 Feb 23
4
hclust question
Dear all,
I have a question with regard to the use of hclust. I would like to be
able to specify my own distance matrix instead of asking R to compute
the distance matrix for me. It is computationally easier for me this
way. My question is: How can I get hclust to accept this?
Thanks,
Ranjan
--
***************************************************************************
Ranjan
2018 Mar 30
3
getting all circular arrangements without accounting for order
Thanks!
Yes, however, this seems a bit wasteful. Just wondering if there are other, more efficient options possible.
Best wishes,
Ranjan
On Thu, 29 Mar 2018 22:20:19 -0400 Boris Steipe <boris.steipe at utoronto.ca> wrote:
> If one is equal to the reverse of another, keep only one of the pair.
>
> B.
>
>
>
> > On Mar 29, 2018, at 9:48 PM, Ranjan Maitra
2018 Mar 30
3
getting all circular arrangements without accounting for order
Dear friends,
I would like to get all possible arrangements of n objects listed 1:n on a circle.
Now this is easy to do in R. Keep the last spot fixed at n and fill in the rest using permuations(n-1, n-1) from the gtools package.
However, what if clockwise or counterclockwise arrangements are the same? I know that half of the above (n - 1)! arrangements are redundant.
Is there an easy way to
2011 Mar 20
3
manova question
Dear friends,
Sorry for this somewhat generically titled posting but I had a question
with using contrasts in a manova context. So here is my question:
Suppose I am interested in doing inference on \beta in the case of the
model given by:
Y = X %*% \beta + e
where Y is a n x p matrix of observations, X is a n x m design matrix,
\beta is m x p matrix of parameters, and e is a
2018 Jan 18
8
reading lisp file in R
Dear friends,
Is there a way to read data files written in lisp into R?
Here is the file: https://archive.ics.uci.edu/ml/machine-learning-databases/university/university.data
I would like to read it into R. Any suggestions?
Thanks very much in advance for pointers on this and best wishes,
Ranjan
--
Important Notice: This mailbox is ignored: e-mails are set to be deleted on receipt. Please
2018 Mar 30
0
getting all circular arrangements without accounting for order
I don't know if this is more efficient than enumerating with distinct
directions and weeding... it seems kind of heavyweight to me:
#######
library(gtools)
directionless_circular_permutations <- function( n ) {
v <- seq.int( n-1 )
ix <- combinations( n-1, 2 )
jx <- permutations( n-3, n-3 )
x <- lapply( seq.int( nrow( ix ) )
, function( i ) {
2018 Mar 30
2
getting all circular arrangements without accounting for order
Jeff,
I wanted to let you know that your function is faster than generating the directional circular permutations and weeding.
Here is the time for n = 10. I compared with just doing the permutations, there is no point in proceeding further with the weeding since it is slower at the start itself.
system.time(directionless_circular_permutations(10))
user system elapsed
1.576 0.000
2007 May 18
2
displaying intensity through opacity on an image
Dear colleagues,
I have an image which I can display in the greyscale using image. On this image, for some pixels, which I know, I want to display their activity based on a third measure. One way to do that would be to color these differently, and use an opacity measure to display the third measure. An example of what I am trying to do is at:
2007 Mar 21
3
question on suppressing error messages with Rmath library
Dear list,
I have been using the Rmath library for quite a while: in the current instance, I am calling dnt (non-central t density function) repeatedly for several million. When the argument is small, I get the warning message:
full precision was not achieved in 'pnt'
which is nothing unexpected. (The density calls pnt, if you look at the function dnt.) However, to have this happen a
2018 Jan 18
1
reading lisp file in R
Thanks! I am trying to use it in R. (Actually, I try to give my students experiences with different kinds of files and I was wondering if there were tools available for such kinds of files. I don't know Lisp so I do not actually know what the lines towards the bottom of the file mean.(
Many thanks for your response!
Best wishes,
Ranjan
On Wed, 17 Jan 2018 20:59:48 -0800 David Winsemius
2012 Mar 19
1
car/MANOVA question
Dear colleagues,
I had a question wrt the car package. How do I evaluate whether a
simpler multivariate regression model is adequate?
For instance, I do the following:
ami <- read.table(file =
"http://www.public.iastate.edu/~maitra/stat501/datasets/amitriptyline.dat",
col.names=c("TCAD", "drug", "gender", "antidepressant","PR",
2018 Mar 30
0
getting all circular arrangements without accounting for order
New function below is a bit faster due to more efficent memory handling.
for-loop FTW!
directionless_circular_permutations2 <- function( n ) {
n1 <- n - 1L
v <- seq.int( n1 )
ix <- combinations( n1, 2L )
jx <- permutations( n-3L, n-3L )
jxrows <- nrow( jx )
jxoffsets <- seq.int( jxrows )
result <- matrix( n, nrow = factorial( n1 )/2L, ncol = n )
k
2018 Jan 18
0
reading lisp file in R
> On Jan 17, 2018, at 8:22 PM, Ranjan Maitra <maitra at email.com> wrote:
>
> Dear friends,
>
> Is there a way to read data files written in lisp into R?
>
> Here is the file: https://archive.ics.uci.edu/ml/machine-learning-databases/university/university.data
>
> I would like to read it into R. Any suggestions?
It's just a text file. What difficulties
2018 Mar 30
0
getting all circular arrangements without accounting for order
If one is equal to the reverse of another, keep only one of the pair.
B.
> On Mar 29, 2018, at 9:48 PM, Ranjan Maitra <maitra at email.com> wrote:
>
> Dear friends,
>
> I would like to get all possible arrangements of n objects listed 1:n on a circle.
>
> Now this is easy to do in R. Keep the last spot fixed at n and fill in the rest using permuations(n-1, n-1)
2017 Oct 09
2
example of geom_contour() with function argument
Can someone please point me to an example with geom_contour() that uses a
function? The help does not have an example of a function, and also I did
not find anything from online searches.
TIA,
BFD
-----------------------------------------------------------------------------------------------
How about geom_contour()?
Am So., 8. Okt. 2017, 20:52 schrieb Ranjan Maitra <maitra at