Displaying 20 results from an estimated 200 matches similar to: "Why are lagged correlations typically negative?"
2005 Aug 03
7
call fortran in R
Hello,
I used a mac G5, R.2.1.1, and G77 3.4.4 and I would like to use and
call a fortran subroutine.
The trouble is that it seems I am not able to correctly load the
compiled code.
Here is what I have done:
In the terminal this how I compiled my fortran code:
R CMD SHLIB ~/Desktop/Fortan_kmeans/kmeans3.f
There is the wrapper I have paste inside de kmeans3.f file:
c
2004 Mar 30
1
classification with nnet: handling unequal class sizes
I hope this question is adequate for this list
I use the nnet code from V&R p. 348: The very nice and general function
CVnn2() to choose the number of hidden units and the amount of weight
decay by an inner cross-validation- with a slight modification to use it
for classification (see below).
My data has 2 classes with unequal size: 45 observations for classI and
116 obs. for classII
With
2005 Apr 20
1
negative p-values from fisher's test (PR#7801)
Full_Name: Martha Nason
Version: 2.0.1
OS: Windows XP
Submission from: (NULL) (137.187.154.154)
I am running simulations using fisher's test on 2 x c tables and a very small
p.value from fisher's test (<2.2e-16) is returned as a negative number. Code
follows.
> set.seed(0)
> nreps.outer <-7
> pvalue.fisher <- rep(NA,nreps.outer)
>
> population1 <- c(
2012 Oct 20
1
Logistic regression/Cut point? predict ??
I am new to R and I am trying to do a monte carlo simulation where I
generate data and interject error then test various cut points; however, my
output was garbage (at x equal zero, I did not get .50)
I am basically testing the performance of classifiers.
Here is the code:
n <- 1000; # Sample size
fitglm <- function(sigma,tau){
x <- rnorm(n,0,sigma)
intercept <- 0
beta
2000 Feb 19
1
problem with glm (PR#452)
I'm having sporadic problems with glm on my alpha workstation running
Compaq Tru64 UNIX V5.0 (I can't replicate the problem on my Linux PC). I
have the same problem whether I use a version of R built with the native
C-compiler or a version compiled with gcc. In both cases I've built with
g77.
I want to do some simulations with a call to glm in each rep. A simplified
version would be
2001 Oct 22
2
OT: compare several graphs
Hi all,
this is OT, but maybe someone can give me a clue. I've got data from eye
tracker experiments (750 data points). These figures show how the data
lock like
|** * ***** |*** ******
| ** **** | * *
| | * *
| | *
|-------------- |---------------
Y axes display velocity, x axes display time, * are the data points.
2005 Sep 08
0
Effect of data set size on calculation
Dear listers,
I have a piece of code which performs an ANOVA type of analysis on 2D GC
data. The code is shown below:
# ANOVA 2D GC analysis
# maxc <- number of samples
# nreps <- number of samples
maxc <- 2
nreps <- 4
sscl <- NULL
cmean <- NULL
#
# Initial stat. variable
#
dftot <- nrow(mat)-1
dfcl <- maxc - 1
dferr <- dftot - dfcl
totmean
2011 Oct 08
2
Permutation or Bootstrap to obtain p-value for one sample
Hi,
I am having trouble understanding how to approach a simulation:
I have a sample of n=250 from a population of N=2,000 individuals, and I
would like to use either permutation test or bootstrap to test whether this
particular sample is significantly different from the values of any other
random samples of the same population. I thought I needed to take random
samples (but I am not sure how
2004 Sep 23
0
nnet and weights: error analysis using V&R example
Dear R-users, dear Prof. Ripley as package maintainer
I tried to investigate the odd error, when I call nnet together with a
'weights' parameter, using the 'fgl' example in V&R p 348
The error I get is:
Error in eval(expr, envir, enclos) : Object "w" not found
I think it is a kind of scoping problem, but I really cannot see, what
the problem exactly is.
and
2004 Sep 23
0
nnet with weights parameter: odd error
Dear R-users
I use nnet for a classification (2 classes) problem. I use the code
CVnn1, CVnn2 as described in V&R.
The thing I changed to the code is: I define the (class) weight for each
observation in each cv 'bag' and give the vector of weights as parameter
of nnet(..weights = weight.vector...)
Unfortunately I get an error during some (but not all!) inner-fold cv runs:
2011 Jan 05
0
Nnet and AIC: selection of a parsimonious parameterisation
Hi All,
I am trying to use a neural network for my work, but I am not sure about my
approach to select a parsimonious model. In R with nnet, the IAC has
not been defined for a feed-forward neural network with a single hidden layer.
Is this because it does not make sens mathematically in this case?
For example, is this pseudo code sensible?
Thanks in advance for your help. I am sorry if this
2004 Jun 14
2
CVnn2 + nnet question
Hi,
I am trying to determine the number of units in the hidden layer
and the decay rate using the CVnn2 script found in MASS directory
(reference: pg 348,MASS-4).
The model that I am using is in the form of Y ~ X1 + X2 + X3...
+ X11 and the underlying data is time-series in nature.
I found the MASS and nnet package extremely useful (many thanks
to the contributors).
However I am getting
2012 Jan 13
0
Example of "task seeds" with R parallel. Critique?
Greetings:
In R parallel's vignette, there is a comment "It would however take
only slightly more work to allocate a stream to each task." (p.6).
I've written down a working example that can allocate not just one,
but several separate seeds for each task. (We have just a few project
here that need multiple streams). I would like to help work that up
for inclusion in the
2003 Dec 12
3
C++: Appending Values onto an R-Vector.
Hi folks. I posted this question a few days ago, but maybe it got lost
because of the code I included with it. I'm having a problem using the
SET_LENGTH() macro in an R extension I'm writing in C++. In a function
within the extension I use SET_LENGTH() to resize R vectors so as to
allow the concatenation of single values onto the vectors -- it's a
"push back" function to
2003 Apr 03
0
debugging question
Dear R-devel,
A user reported a strange problem with predict.randomForest in the
randomForest package yesterday, and I'm baffled by it. The code at the end
of the message produces the error. The problem is that, in
predict.randomForest, there's a .Fortran call to "runforest". One of the
arguments passed in is "countts", which is a vector of doubles. The error
2003 Dec 10
0
C++: SET_LENGTH() Over Many Iterations?
In a C++ extension to R (v 1.8.1), I've been experimenting with a
generic "push back" function to tack one value at a time onto the end
of an R vector created within the extension. After calling this
function a certain number of times Rgui.exe (I'm writing in Windows
using Visual Studio .NET 2003) will fail with an Access Violation,
which doesn't happen when I pre-allocate
1998 Nov 03
0
Is Samba typically slower sending files than receiving?
Is Samba typically slower sending files than receiving?
I have seen this both at home and at work.
Sometimes the throughput is 1/2 when I copy files from Samba
than when I copy to Samba (From WinNT and Win95/98)
The Players --------------------------------------------------------------------------------------
I have been playing with the options for three days.
I have an NT server that is old.
2015 Feb 05
0
Typically end-to-end 'delay' of live audio
On 02/05/2015 02:45 PM, Tony wrote:
> I have an audio device driver for a live feed that produces Opus
> frames, if I were to use icecast, what sort of real-time delay can I
> expect? 3-5s? 5-10s? more?
Likely that or more. This highly depends on the client side buffers.
Icecast itself doesn't buffer much and that can be disabled by turning
off the burst-on connect functionality.
2009 Jul 22
1
R extract vertices for polygon
Dear R users,
I'm trying to extract from a given matrix (GROUP) the coordinates of the vertices of the different groups (i.e. 3, 7, 1 . . .) to plot the polygons to delineate the area in which each group "wins" and colour it diferentially. I can make a simple point plot, but I would like to add polygons with full colored area. The example is with a 5x5 matrix, but I'm working
2011 Feb 02
2
Help with one of "those" apply functions
Hello there,
I'm still struggling with the *apply commands. I have 5 people with id's
from 10 to 14. I have varying amounts (nrep) of repeated outcome (value)
measured on them.
nrep <- 1:5
id <- rep(c("p1", "p2", "p3", "p4", "p5"), nrep)
value <- rnorm(length(id))
I want to create a new vector that contains the sum of the