Displaying 20 results from an estimated 1000 matches similar to: "Ways to speed up R code?"
2005 Jun 21
1
How to plot circular data in the directions of 0, 0.5pi, pi and 1.5pi
Hi R users,
I use plot.circular(rad, stack=T,bins=4) and could just obtain the four
stacks in the directions of 45, 135, 225 and 315 degrees. But I want them in
0, 90, 180 and 270 degrees. Is there any parameter or any other function to
make it? Thanks for helping a R beginner.
--
Xiaohua Dai, Dr.
--------------------------------------------------------------------------------
Centre for
2005 Sep 12
1
help for linear-circular correlation
Hi R-profs,
Maybe my question is a little off topic. Could any one tell me how to
calculate a linear-circular correlation coefficient and its p-values?
I had a quick look at circular and CircStats packages and did not find
the related function.
Thanks for any kindly help.
Xiaohua
--
Xiaohua Dai, Dr.
Centre for Systems Research, Durban Institute of Technology
P.O.Box 953, Durban 4000, South
2005 Aug 03
1
help for cell2nb and queencell in spdep package
Dear Dr. Bivand and R-users,
I have a 5 by 5 grid, say, location[1:5,1:5], and I want to know the
indices of 8 neighbours of each cell. For example, for location[2,2], its
neighbour coordinates are [1,1:3], [2,1], [2,3] and [3,1:3]. Sometimes I
also need to remove edge effects (torus = TRUE).
I have tried "cell2nb" function in your spdep package. Here's my example:
> neigh
2005 Jul 12
1
question for IF ELSE usage
Hi R users,
Maybe the question is too simple.
In a IF ... ELSE ... statement "if(cond) cons.expr else alt.expr", IF and
ELSE should be at the same line?
For example,
if (x1==12)
{
y1 <- 5
}else
{
y1 <- 3
}
is right, while
if (x1==12)
{
y1 <- 5
}
else # Error: syntax error
{
y1 <- 3
}
is wrong?
Thanks
--
Xiaohua Dai
2006 May 12
1
[ESRI-L] outline polygons of point clumps
Sorry, I did not make my question clear. Since I have a point theme
with many points, some of them may clump together. the problems here
are:
1. how to find clumps in a point theme?
2. the convex-hull extension I found only deal with all the points in
a theme at each time? how to make each convex hull around each point
clump automatically?
Thanks.
Xiaohua
On 5/12/06, Bob Booth <bbooth
2006 Feb 15
1
Multiple comparison for circular data
Hi All,
Does anyone know how to compare the means of several circular-data
samplings? Any related websites, references and softwares?
Thanks
Xiaohua
--
Xiaohua Dai, Dr.
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2006 Jun 29
2
How to use a for loop to generate two sequences
Hi R users,
Hope the question is not too simple:
How to use a for loop to generate two lists as below:
testlist <- list(test1, test2, ..., test1000)
stringlist <- list("test1","test2",...,"test1000")
Thanks
Xiaohua
2006 Jun 14
1
set.seed
Hi R users,
Sorry for a simple question:
I found different people use different i in set.seed(i), are there any
rules to choose an i or one can choose as he likes?
Thanks
Xiaohua
2005 Jun 30
3
[OT] gmail filter for R-help and R-devel lists
This is slightly off-topic but I would be interested in whether anyone
has succeeded in creating a filter expression for Google's gmail
system that will select messages sent through the R-help and R-devel
lists. It seems as if it should be easy to select on '[R]' or '[Rd]'
in the subject line but I haven't been able to work out the exact
syntax that would do this and not
2005 Jul 13
5
maps drawing
Hello,
is there a package in R that would allow map drawing:
coastlines, country/state boundaries, maybe
topography,
rivers etc?
Thanks for any guidance,
Mark
2009 Aug 13
1
When using randomForest, what's the effect to "set.seed"?
Greetings,
When reading the random forest manual by Liaw, in the examples
"set.seed" is always used before building a forest.
Does it matter if I don't set the seed?
If I set a different seed manually each time I build a forest, will this
give better randomness?
Thank you all in advance!
--
====================
EcoInformatics Lab
2005 Jul 06
2
How to sample x-y coordinates from GIS files
Hi Gurus!
I have a job that is to get randomly samples from point-based GIS data (sp
called shape GIS files) under the total sum resctricted.
For example, I would like to take random smaples under the 1000 persons in
each city.
The randomly sampled persons should not be over 1000 any case.
Thank you in advance,
--
Kum-Hoe Hwang, Ph.D.
Phone : 82-31-250-3283
Email : phdhwang@gmail.com
2005 Oct 13
3
How to generate for one vector matrix
Is there any routine to generate for one vector matrix.
If I have X I want to generate start from zero to maximum value each vector.
For example, I have a vector x = (4,2,3,1,4)
I want to generate n=6 times, for 4, start 0 to 4, then 2 start 0 to 2, ect.
The result something like this:
generate(x,n=6)
1,1,2,1,4
1,2,3,0,3
4,0,1,1,1
3,1,0,1,4
0,0,3,0,0
4,1,3,0,4
Could anyone help me. Thanks.
2010 Jul 11
1
Durban Watson statistics
I would like to do the Durban-Watson test on a time series of log returns.
2 questions:
1) If I am just trying to find out if there is serial correlation, what do I do for the residuals? there is no model, so do I just use the log returns (time series) itself?
2) what is the code in R to accomplish this?
Regards
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2005 Jun 30
5
答复: fail in adding library in new version.
Dear Gabor,
Thank your for helping me so much!
I have loaded R the newest version 2.1.1. Then I setup it in the path of D:\program files\R\
1. unpack tools.zip into c:\cygwin
2. install Active perl in c:\Perl
3. install the mingw32 in c:\mingwin
4. add "c:\cygwin; c:\mingwin\bin" in "Control Panel -> System -> Advanced -> Environment Variables -> Path ->
2006 May 11
1
package update problem
Hi all,
>From late April, everytime when I update my packages, the package
"gap" is always on the list of "packages to be updated". I try to
download and install the gap zip file from CRAN. However, the same
problem still remains. No such problem for other packages.
> Sys.info()
sysname release
2004 Sep 30
3
Is there any way to release memory in running time?
Hi all,
I am doing some intensive computation right now. My system is Pentium4 3.20G
+ 1.0G RAM + WindowsXP + R1.9.1. It seems my computer is very powerful.
However, when I do some simple matrix algebra operations based on a matrix
(DD) with dimension 5000000 by 2, I found that the consumption of RAM is
huge. For example, the command a <- 1 - DD[,2] eats my 100M RAM. Does anyone
know how
2011 Apr 07
1
comparing ARIMA model to data
hi,
i am trying to teach myself about ARIMA models. i have followed examples
from a number of sources and have more or less got the hang of how it
works. i would like to compare the output from the fitted model to the
original data. is this possible? or even a meaningful thing to do?
to be clear, for example, having generated a fit to some data using
> fit <- arima(LakeHuron, order = c(1,
2010 Jan 04
1
glmer (lme4), glmmPQL (MASS) and xtmepoisson (Stata)
Dear R users,
I'm trying to specify a generalized linear mixed model in R, basically a Poisson model to describe monthly series of counts in different regions.
My aim is to fit subject-specific curves, modelling a non-linear trend for each region through random effects for linear splines components (see Durban et al, Stat Med 2005, or " Semiparametric regression" by Ruppert et al,
2005 Jan 11
1
CUSUM SQUARED structural breaks approach?
Dear all,
Does anyone know where there is R or S code for the CUSUM SQUARED
structural breaks approach? (Brown, Durban and Evans, 1975 - used in
Pesaran and Timmerman, 2002)
The problem is that the breaks package only appears to offer the
standard 'unsquared' CUSUM, even though it appears most think it is
inferior to the squared version. It might appear to be a relatively
simple