Displaying 20 results from an estimated 1000 matches similar to: "general genetic algorithm / simulated annealing framework"
2004 Jan 30
1
a problem loading package 'subselect'
Hi,
I downloaded the subselect package from CRAN and installed it in the
system wide R library path. During installation the package compiled the
fortran sources with no errors.
However, when loading the library gives me an error:
> library(subselect)
Error in dyn.load(x, as.logical(local), as.logical(now)) :
unable to load shared library
2004 Jan 20
2
graph algorithms in R
Hi,
I was wondering if there are any packages available that can represent
mathematical graphs along with functions to manipulate them? Google
did'nt turn up anything ( I may be asking too much of R :-/ )
Thanks,
-------------------------------------------------------------------
Rajarshi Guha <rxg218 at psu.edu> <http://jijo.cjb.net>
GPG Fingerprint: 0CCA 8EE2 2EEB 25E2 AB04
2003 Oct 01
1
question about predictions with linear models
Hi,
this question is probably very obvious but I just cant see where I
might be going wrong.
I'm using the lm() function to generate a linear model and then make
predictions using a different set of data.
To generate the model I do (tdata & pdata are matrices of observations
and parameters, tdepv, pdepv are response vectors)
x <- as.data.frame(tdata)
x$tdepv <- tdepv
2003 Oct 05
1
clicking on a point on a plot
Hi,
is this feature available in R?
I plot some data using plot(). Clicking on a point I'd like information
regarding that point. I realize that I could use locator() but this
gives me the X & Y values. Is it possible to somehow use locator to give
more information regarding the point chosen - say, which vector the
point was taken from.
It seems that R itself does not do this - is
2003 Oct 06
1
vif() from Design and car
Hi,
I've been generating linear models with lm(). I wanted to look at the
VIF's for the coefficient. Using the vif() function from the package
Design, I would get unusually high VIF's.
However using vif() from the car package I get more reasonable values
(ie in line with the quality of the model).
What is the difference between the two vif functions? (I dont have
access to the
2003 Dec 03
2
nameless functions in R
Hi,
I have an apply statement that looks like:
> check.cols <- function(v1, v2) {
+ return( identical(v1,v2) );
+ }
> x
[,1] [,2] [,3]
[1,] 1 3 3
[2,] 4 5 4
[3,] 2 7 6
> apply(x, c(2), check.cols, v2=c(7,8,9))
[1] FALSE FALSE FALSE
Is it possible to make the function check.cols() inline to the apply
statement. Some thing like this:
apply(x,
2004 Feb 12
2
variances of values predicted using a lm object
Hi,
is there a function in R that will give me the variances of a
predicted values obtained using predict.lm().
If no function is available I would need to calculate them myself -
which involves taking the inverse of X'X (' indicating transpose)
where X is my model matrix. I know that calculating an inverse directly
is not a good idea in general - could anybody suggest a way around
2004 Apr 19
1
using subscripts in a plot title with 2 lines
Hi,
I'm making a plot in which the title takes up two lines. The title
contains a subscript but when I look at the plot it does'nt seem tocome
out properly. The code I'm using is:
xtxt = expression(paste('Observed -log( ', IC[50], ' )'))
ytxt = expression(paste('Predicted -log( ', IC[50], ' )'))
mtxt = expression(paste('Plot of Observed
2004 Jun 10
1
a scope problem
Hi,
I have some code that looks like:
dftc <- df[sets$tcset,]
pt <- numeric(nrow(dftc))
sub <- 1:nrow(dftc)
for (i in 1:nrow(dftc)) {
n <- nnet( fmla, data=dftc, weights=wts, subset=sub[-i], size=4,
decay=0.01)
pt[i] <- predict( n, dftc[ i, ], type='class' )
}
However running this give me the error:
Error in eval(expr, envir, enclos) :
2005 Mar 24
1
Rggobi package
Hi,
I have an old version of the Rggobi package which now wont load (R
2.0.0). Looking for the package on CRAN does'nt turn up anything and
the links on http://www.ggobi.org/RSggobi.html don't work.
Does anybody know where I can get the latest version of RSggobi or
Rggobi?
Thanks,
-------------------------------------------------------------------
Rajarshi Guha <rxg218 at
2005 Sep 21
1
R , Java & DCOM
Hi,
I am working on a Java project that will run primarily on Windows. As
part of the project I would like to use the R engine.
However, from what I have seen on this list & the SJava list, installing
SJava on Windows can be troublesome.
As a result I was wondering if anybody had used DCOM to access R from a
Java program on Windows (if it is all possible).
Any pointers to documents and/or
2005 Dec 08
1
reference for a fortune quote
Hi, there is a quote in the fortunes package:
To paraphrase provocatively, `machine learning is statistics minus any
checking
of models and assumptions'.
-- Brian D. Ripley (about the difference between machine learning and
statistics)
useR! 2004, Vienna (May 2004)
Was this statement made in a presentation? If so, would it be possible
to get a reference for the presentation?
2006 Apr 26
1
accessing a SOAP based web service from R
Hi,
I have a number of web services that run on a server and can be
accessed via SOAP as well as by creating a specific URL.
Now, for certain services, the argument that I need to send is about 10
to 20 characters and the URL approach works fine. However if the
argument is a few kilobytes I would rather create a SOAP packet and send
that off.
So my first question is: is there a package that
2003 Sep 30
2
subsetting a matrix
Hi,
I'm trying to take a set of rows and columns out of a matrix. I hve
been using the index aray approach. My overll matrix is X and is 179 x
65. I want to take out 4 columns and 161 rows.
Thus I made a 161 x 2 array I and filled it up with the row,col indices.
However doing,
X[ I ] gives me a vector of the extracted elements. Is there anyway I
can coerce this into a 161 x 4 matrix?
2004 Dec 05
1
matrix of 1,0's to a data.frame of factors
Hi, I have an integer matrix consisting of 1's and 0's and I would like
to convert this to a data.frame where each column of the matrix becomes
a factor variable.
Now, some columns of the matrix have only 1's or only 0's as a result
there is only 1 level for those columns in the data.frame. However it is
required that each factor have 2 levels. So my solution is:
m <-
2004 Jun 21
2
visualizing a list of probabilities
Hi,
I'm using nnet to work on a 2 class classification problem. The result
of my code is data.frame of true class, predicted class and associated
probability.
One way of summarizing the data is by a confusion matrix. However are
there any graphical ways I could represent the data - specifically, I'd
like to show the probabilities associated with each member of my
prediction set?
(I
2004 May 20
2
column sorting a matrix with indices returned
Hi,
I'm trying to translate some Matlab code to R and I'm trying to
implement the behavior of Matlab's sort() which when applied to a matrix
will sort the columns returning the column sorted matrix as well as a
matrix of permuted indices.
Doing:
> x <- matrix(c(3,4,2,6,3,4,8,7,5), nr=3)
> x
[,1] [,2] [,3]
[1,] 3 6 8
[2,] 4 3 7
[3,] 2 4 5
2003 Dec 03
3
checking for identical columns in a mxn matrix
Hi,
I have a rectangular matrix and I need to check whether any columns
are identical or not. Currently I'm looping over the columns and
checking each column with all the others with identical().
However, as experience has shown me, getting rid of loops is a good idea
:) Would anybody have any suggestions as to how I could do this job more
efficiently.
(It would be nice to know which
2004 Sep 15
1
fractal dimension of an image
Hello, I have a problem that I think can be solved in R but I'm not sure
how to tie things together.
I have a digital image of a crystal growth in 2 dimensions. And my aim
is to calculate the fractal dimension of the crystal. I was planning to
use the box counting method.
So I need to read in the image in R (for which I can use the pixmap or
rimage packages) and then draw a grid over at a
2006 Mar 10
2
appending objects to a file created by save()
Hi,
I've been slowly transitioning to saving sets of objects for a project
using save() rather than cluttering my workspace and then doing
save.image()
However, sometimes after I have done say:
save(x,y,z, file='work.Rda')
and I reload it a little later and I see that I also want to save
object p. Currently I need to do:
save(x,y,z,p, file='work.Rda')
Is there any way