Displaying 20 results from an estimated 600 matches similar to: "hclust question"
2001 May 13
1
CART in R
Can anyone please help me out? I would like to do CART (classification
and regression trees) in R. Is this at all
possible? If so, how?
Thanks,
Ranjan
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Ranjan Maitra, Department of Mathematics and Statistics,
University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
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 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
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Important Notice: This mailbox is ignored: e-mails are set to be deleted on receipt. Please
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 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
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 ) {
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
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:
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 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
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
2012 Dec 28
4
efficiently multiply different matrices in 3-d array with different vectors?
Hello,
I have been wondering of an efficient way to do this:
I have an n x m x p array Z and a p x n matrix Y.
I want to multiply each of the n matrices with the corresponding column
vector of Y.
In other words, I am wanting to matrix multiply:
Z[i, ,] %*% Y[, i]
which will give me a (two-dimensional) array or matrix of dimension n x
p with the i'th row storing the above.
Any pointers
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
2018 Jan 18
0
reading lisp file in R
It seems the file contains records, with each record having 18 fields.
I would use awk (standard unix tool), creating an awk script to process the
file
into a new file with one line for each record, each line with 18 fields,
say comma-separated.
The csv file can then be easily read into R via the function read.csv.
HTH,
Eric
On Thu, Jan 18, 2018 at 6:22 AM, Ranjan Maitra <maitra at
2012 Jul 21
2
two questions re: the use of lattice
Dear friends,
I have two questions regarding the use of lattice. First some code:
## begin code
z <- cbind(rep(c("BIC", "ICL", "s_v", "Q_v", "sig-q",
"s_lsk", "s_lML", "s_mlsk", "s_mlML", "s_la8",
"s_haar"), each = 250), rep(c(5, 10, 20, 30, 50), each = 50))
z
2012 May 07
1
commenting out a block of R code
Dear friends,
Is there an easy way of commenting out a block of R code after it has
been written? (I am aware that R-aware editors can insert #
line-by-line while it is being written, but I want to basically block
out chunks of R code in a few strokes.)
This question was asked on this mailing list some time ago: Professor
Ripley's answer was to try the following:
2007 Jul 25
2
using contrasts on matrix regressions (using gmodels, perhaps)
Hi,
I want to test for a contrast from a regression where I am regressing the columns of a matrix. In short, the following.
X <- matrix(rnorm(50),10,5)
Y <- matrix(rnorm(50),10,5)
lm(Y~X)
Call:
lm(formula = Y ~ X)
Coefficients:
[,1] [,2] [,3] [,4] [,5]
(Intercept) 0.3350 -0.1989 -0.1932 0.7528 0.0727
X1 0.2007 -0.8505 0.0520