Displaying 20 results from an estimated 2000 matches similar to: "Using R in a web application"
2008 May 16
1
Dimensions of svd V matrix
Hi,
I'm trying to do PCA on a n by p wide matrix (n < p), and I'd like to
get more principal components than there are rows. However, svd() only
returns a V matrix of with n columns (instead of p) unless the argument
nv=p is set (prcomp calls svd without setting it). Moreover, the
eigenvalues returned are always min(n, p) instead of p, even if nv is set:
> x <-
2009 Nov 27
2
Symmetric Matrix classes
Hi,
I'd like to store large covariance matrices using Matrix classes.
dsyMatrix seems like the right one, but I want to specify just the
upper/lower triangle and diagonal and not have to instantiate a huge
n^2 vector just for the sake of having half of it ignored:
Dumb example:
M <- new("dsyMatrix", uplo="U", x=rnorm(1e4), Dim=as.integer(c(100, 100)))
diag(M) <- 1
2008 Apr 03
1
Lapack error in Design:::ols
Hi,
I'm trying to use Frank Harrell's Design:::ols function to do regression
of y (numeric) on the interaction of two factors (x1 and x2), but Lapack
throws an error:
> library(Design)
...
> load(url("http://www.csse.unimelb.edu.au/~gabraham/x"))
> ols(y ~ x1 * x2, data=x)
Error in chol2inv(fit$qr$qr) : 'size' cannot exceed nrow(x) = 20
> traceback()
2008 May 18
1
predict.prcomp: 'newdata' does not have the correct number of columns
Hi,
I'm doing PCA on wide matrices and I don't understand why calling
predict.prcomp on it throws an error:
> x1 <- matrix(rnorm(100), 5, 20)
> x2 <- matrix(rnorm(100), 5, 20)
> p <- prcomp(x1)
> predict(p, x2)
Error in predict.prcomp(p, x2) :
'newdata' does not have the correct number of columns
> dim(x2)
[1] 5 20
> dim(p$rotation)
[1] 20 5
2009 Mar 10
1
S4 generic masking S3 generic when using namespace
Hi,
I have two example packages, test1 and test2, where the only code in
them is:
setGeneric("predict", function(object, ...) standardGeneric("predict"))
(get them from http://www.cs.mu.oz.au/~gabraham/test1.tar and
http://www.cs.mu.oz.au/~gabraham/test2.tar)
The difference between them is that first does not have a namespace, and
loads fine. The second has a namespace
2008 Aug 12
1
Conflict between octave3.0-headers and r-base-dev
Hi,
I'm using Ubuntu Hardy i386, and the R 2.7.1 Ubuntu packages from CRAN.
The CRAN r-base-dev package depends on refblas3-dev or atlas3-base-dev,
but octave3.0-headers depends on libblas-dev. The two blas packages seem
to conflict, so r-base-dev and octave3.0-headers can't be installed
together.
Is this a known issue?
Thanks,
Gad
$ sudo apt-get install octave3.0-headers
Reading
2010 May 26
2
cran2deb Packages.bz2 Hash Sum mismatch
Hi,
I'm using Ubuntu 9.10 amd64 with cran2deb packages (I know it's meant
for Debian, it's worked fine for me for many months).
Recently apt-get update has to started to complain:
...
Hit http://debian.cran.r-project.org testing/ Release
Get:1 http://debian.cran.r-project.org testing/ Packages [515kB]
Fetched 1B in 3s (0B/s)
W: Failed to fetch
2008 Oct 09
2
Singular information matrix in lrm.fit
Hi R helpers,
I'm fitting large number of single factor logistic regression models
as a way to immediatly discard factor which are insignificant.
Everything works fine expect that for some factors I get error message
"Singular information matrix in lrm.fit" which breaks whole execution
loop... how to make LRM not to throw this error and simply skip
factors with singularity
2008 Dec 09
1
ARMA
Hi!
Is there any package or function on R to ARMA models (Box & Jenkins, without
sazonality and trend) with resources to automatic identification for p and q
?
Regards,
Raphael Saldanha
Brazil
[[alternative HTML version deleted]]
2008 Dec 11
1
help with predict in stats4
Hi,
We're using stats4 for a logistic regression. The code is
chdreg.logit2 <- glm(chd ~ age + sex, family = binomial)
summary(chdreg.logit2)
oddsratios <- coef(chdreg.logit2)
exp(oddsratios)
# Calculate model predicted values
pred <- predict(chdreg.logit2,type="response")
The glm part runs fine, and up to now so has the predict function.
However, now we're
2009 Feb 08
1
Hessian?
I am new to 'R' and also new to the concept of a 'Hessian' with non-linear optimization. I would like to avoid going through all of the reference articles given with ?optim as access to a library is not handy. Would someone be able to elighten me on what is in the Hessian matrix if 'hessian = TRUE' with optim? The documentation indicates that this is a numerically
2009 Jun 17
1
Predict Fanny Membership
Hello List,
My question is an elementary one. I have run a fuzzy kmeans cluster using
FANNY to group freshwater fish assemblages. I then went in the field to
validate that classification and have retrieved new assemblage data for a
new suite of streams. Therefore I would like to use Predict to determine how
well the original clustering fits the new data. However I have not figured
out a
2009 Jan 20
2
Confidence intervals in ccf()
Hi,
I have been running the ccf() function to find cross-correlations of time
series across various lags. When I give the option of plot=TRUE, I get a
plot that gives me 95% confidence interval cut-offs (based on sample
covariances) for my cross-correlations at each lag. This gives me a sense of
whether my cross-correlations are statistically significant or not.
However, I am unable to get R to
2008 Oct 14
1
Labour Statistics
Hi everyone,
This is not so much of an R question as a statistics question. I
currently work for the largest pre employment screening company in
Canada. Upper management has noticed that noticed that usually a month
or so before any big kind of economic shock happens, that our incoming
files (requests for a background check) jump up or down.
As the company statistician, they've asked me
2008 Sep 09
4
PCA and % variance explained
After doing a PCA using princomp, how do you view how much each component
contributes to variance in the dataset. I'm still quite new to the theory of
PCA - I have a little idea about eigenvectors and eigenvalues (these
determine the variance explained?). Are the eigenvalues related to loadings
in R?
Thanks,
Paul
--
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2009 Apr 09
1
arima on defined lags
Dear all,
The standard call to ARIMA in the base package such as
arima(y,c(5,0,0),include.mean=FALSE)
gives a full 5th order lag polynomial model with for example coeffs
Coefficients:
ar1 ar2 ar3 ar4 ar5
0.4715 0.067 -0.1772 0.0256 -0.2550
s.e. 0.1421 0.158 0.1569 0.1602 0.1469
Is it possible (I doubt it but am
2008 May 16
1
64-bit R and cache memory
Dear all,
I have a few questions regarding the 64 bit version of R and the cache
memory R uses.
-----------------------------------
Computer & software info:
OS: kUbuntu Feasty Fawn 7.04 (64-bit)
Processor: AMD Opteron 64-bit
R: version 2.7.0 (64-bit)
Cache memory: currently 16 GB (was 2 GB)
Outcome of 'limit' command in shell: cputime unlimited, filesize
unlimited, datasize
2009 Apr 07
1
R segfaulting with glmnet on some data, not other
Hello R-help list,
I have a piece of code written by a grad student here at BU which will segfault when using one data set, but complete just fine using another. Both sets are just text files full of real numbers.
It seems like a bug within R. It could be a bug within her data, but
again, her data is just a bunch of floats, so her data could be
triggering a bug within R. I have tried this
2009 Feb 02
3
Environmental variables
I use a Mac (10.4.11 Mac Os X).
In my .tcshrc I define an environmental variable MY.
Is it possible to find out its value from inside R? When one loads
R for Mac OS X Cocoa GUI written by:
Simon Urbanek
Stefano M. Iacus
are files like .tcshrc read by R?
Can I make the value of this environmental variable available to R?
Sys.getenv() produces a lot of output, with the values of many
2009 Nov 25
2
R or C++ on FreeNX servers
Hi all,
I have just found out that the machine learning group in our Faculty has
a lot of spare capacity on their FreeNX servers. I do not know a lot
about these beasts but I understand that they are a free version of
something produced by a firm called "NoMachine".
They are designed for executing parallel algorithms and I thought that
they might be of use in a project of mine