Displaying 20 results from an estimated 2000 matches similar to: "EM algorithm"
2006 Oct 13
3
Rmpi performance
Dear R users,
we are trying to do some parallel computing using library(snow).
In particular we have a cluster with 3 nodes
>cl <- makeCluster(3, type = "MPI")
3 slaves are spawned successfully. 0 failed.
and we want to compute the function op_mat (see below) first with the
master and then with the cluster using system.time for checking the
computational performance.
2006 Jun 15
1
SSPIR problem
Dear R-Users,
I'm using SSPIR package for a spatio-temporal application.
Is it possible to modify the structure of the involved matrixes (Fmat,
Gmat, Vmat,Wmat)?
I want to create a model like this
#y(t)=k*theta(t)+epsilon(t)
#theta(t)=h*theta(t-1)+eta(t)
#epsilon(t) N(0,V) V=sigma2*I
#eta(t) N(0,W) W=sigma2_eta
where the state variable theta has dimension 1(p=1) and at
2009 Jul 01
1
RScaLAPACK package with OpenMPI
Hi all,
I'm using RScalapack library for parallelizing some heavy matrix
operations required by MCMC methods for spatio-temporal models. The
package reference manuals (dated 2005) states that the library needs
LamMPI to work but we have a Linux Cluster with OpenMPI. We have found
(http://cvs.fedoraproject.org/viewvc/devel/R-RScaLAPACK/) a patch for
OpenMPI but we are wondering if in the
2006 Nov 23
2
loading libraries on MPI cluster
Dear R-users,
we are using library(snow) for computation on a linux cluster with RMPI.
We have a problem with clusterEvalQ: after launching clusterEvalQ it seems
loading the required library on each node but if we type a function
belonging to the loaded package R doesn't find it.
> library(snow)
# making cluster with 3 nodes
> cl <- makeCluster(3, type = "MPI")
Loading
2007 Mar 19
1
data.frame handling
Dear R-users,
I have a little problem that I can't solve by myself.
I have a data frame with 2 factors and 8 observations (see the following
code):
y <- c(1,1,1,2,2,3,3,3)
y <- factor(y)
levels(y) <- c("a","b","c")
x <- c(1,2,3,1,2,1,2,3)
x <- factor(x)
levels(x) <- c("x","y","z")
X <-
2008 Jul 21
2
avoid loop with three-dimensional array
Dear R user,
I'm trying to find a solution for optimizing my code. I have to run a 50.000
iteration long simulation and it is absolutely necessary to have an
optimized code.
I have to do this operation
*sum_t ( t(X_t) %*% A %*% X_t )*
where X_t is a (d*k) matrix which changes in time and A is a constant in
time (d*d) matrix.
I have put all my X_t in a three dimensional array X of dimension
2001 Sep 06
2
Array as time series?
Dear R-helpers,
I have 4-dimensional atmospheric data (x,y,z,t), which I want to analyse
on spatio-temporal diversities.
As far as I understand there only exists the possibility to construct
time series as two-dimensional matrices (mts).
For the moment, I hold it in different objects:
1. a four-dimensional array for the spatial related analyses
2. a two-dimensional mts timeserie, which was
2011 Jul 12
1
Cross K Ripley's function and "spatio-temporal interaction power"
Dear All,
I have a collections of spatial data. I have to analyze pairs of these
point patterns to test their spatial interaction. I was moving towards
the cross K Ripley's function. The problem, however, are the following:
1) What is the best way to get a single real value that represents the
interaction "power"?
2) How to obtain a value that even allows me to rank the pairwise
2005 Jan 27
2
Request for help
My name is Michela Marignani and I'm an ecologist trying to solve a problem
linked to knight' s tour algorithm.
I need a program to create random matrices with presence/absence (i.e. 1,0
values), with defined colums and rows sums, to create null models for
statistical comparison of species distribution phenomena.
I've seen on the web many solutions of the problem, but none provides
2004 Nov 16
3
memory allocation
Dear sirs,
I'm using the Splancs package to compute standard errors of the estimates of a
spatio-temporal k function.
When I use as spatial and temporal distances too long vectors (respectively 60
and 80 entries) for a dataset of 1000 observations, R gives me the message
Error: cannot allocate vector of size 180000 Kb
Reached total allocation of 512 Mb.
I ran the function memory.size()
2002 May 13
1
Spatio-temporal analysis of homicide rates
Dear R-listers,
I would like to carry out a very basic descriptive analysis of homicides
rates in Italy, taking into account both the spatial dimension (103
provinces) and the temporal dimension (10 years), but no covariates. In
practice, what I would like to do is to describe spatio-temporal variation
of homicide rates, identifying those combinations of province-year where
the homicide rate
2006 Jun 27
2
Survival
? stato filtrato un testo allegato il cui set di caratteri non era
indicato...
Nome: non disponibile
Url: https://stat.ethz.ch/pipermail/r-help/attachments/20060627/84d9bd54/attachment.pl
2017 Oct 06
1
How to resolve this error
> library(SpatioTemporal)
> library(plotrix)
> library(maps)
> palay.cov<-read.csv("C:/Users/BEDANA-PC/Desktop/STThesisWD/Thesis
Data/palay.covar.csv")
> palay.o<-read.table("C:/Users/BEDANA-PC/Desktop/STThesisWD/Thesis
Data/palay.obs.txt")
> palay.obs<-as.matrix(palay.o)
> palay.stc<-read.table("C:/Users/BEDANA-PC/Desktop/STThesisWD/Thesis
2005 Dec 20
1
x axis
Hello,
I write to know how can I modify the x axis : when I plot a survival object, R plots a graph with x values = 0, 10, 20, 30 while I want a graph with values 0, 6, 12, 18, 24 in the x axis. How can I do this? In R 2.1.1 version there was "time.inc" in survplot, but in version R 2.2.0 there isn't it!
I am sorry for my english and I hope that you understand my problem.
Thank you
2009 Nov 18
1
foor loop - undefined columns selected error
Dear R-Help Members,
I am trying to read and analyse a set of 100 csv files.
I need work only on some columns in each of those, so I decided to use
a for loop, isolate the
column in each file to work on, but then an error mesage appear:
"undefined columns selected"
Here is my code:
setwd("F:/Data/")
a<-list.files()
for (x in a) {
? u<-read.csv(x, header=T,
2008 Dec 10
1
subset point data set by distance ranges
Greetings
I'm using R 2.8 with recent (last month) versions of the packages I need to
use at present.
I'm interested in examining hierarchical spatio-temporal patterns in a data
set. The data consist of 94 points (X, Y, UTM coordinates) at which catch
rates for a fish were recorded and there are also estimates of prey
available for these fish at the same locations.
2013 Apr 08
1
Computational Ecologist Job at NOAA in Silver Spring, MD -- Marine Wildlife Spatial Modeling in R
The NOAA National Centers for Coastal Ocean Science is hiring a
Computational Ecologist, a statistical/computational ecologist with
experience fitting advanced spatial models to marine wildlife survey
data (e.g., seabirds and marine mammal transects, fisheries trawl
surveys) in R and other statistical languages. This is a full-time,
long-term stable contract position. We are looking for an
2008 Oct 01
1
Simon Wood GAMsetup
Dear Simon, Thank you for your quick reply!
I used to perform the GAMsetup in the following manner:
GAMsetup sintax:
x.summer: vector used for construct the spline
knots<-14
N<-length(x.summer)
x<-array(x.summer,dim=c(1,N))
G<-list(m=1,n=N,nsdf=0,df=knots+1,dim=1,s.type=0,by=0,by.exists=FALSE,p.order=0,x=x,n.knots=knots,fit.method="mgcv")
H<-GAMsetup(G)
with the
2011 Feb 14
1
How to group data by day
Hi everybody,
I'm a beginner in R and I'm having a hard time grouping my data by day.
The data are in this format:
id; words
2005-07-07T09:59:56Z; 35
2005-07-07T10:01:39Z; 13
2005-07-08T10:02:22Z; 1
2005-07-09T10:03:16Z; 23
2005-07-10T10:04:23Z; 39
2005-07-10T10:04:39Z; 15
I've transformed the date strings in dates with the function:
london$id <- transform(london$id,
2005 Oct 19
6
forrest plot
Hi,
can you tel me how can I make a Forrest Plot with R?
It is possible and easy or are there a more practical free software available?
Than you
Mic
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