Displaying 20 results from an estimated 100 matches similar to: "lme: problems with corARMA"
2004 Jul 23
0
problem lme using corSymm()
Hi,
I got a computational problem with lme (nlme library R 1.9.1) using
corSymm(). Here is the data:
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 0.19639793 0.09127954 0.11733288 0.07598273 0.06545106 0.06211532
[2,] 0.22773467 0.10981912 0.16052847 0.38101187 0.18353474 0.24072918
[3,] 0.46743388 0.45733836 0.32191178 0.43356107 0.39159746 0.53984221
[4,]
2005 Dec 02
1
covariance structures in lmer
Hi,
I usually use lme from the nlme library. Now I have read an article about
lmer in Rnews and lmer seemed to me more comfortable to use. Unfortunately,
I didn't find out how to use covariance structures (e. g. corSymm(),
corAR1()). Is there a way to use them similarly as in lme ? Is it
implemented ? If somebody knows, please let me know.
Thank you very much in advance,
Stephan
2004 May 10
2
trellis plot problem with R-1.9.0-1
I tried following commands:
amp~time|subject/trial #this was the grouping structure of the data
plot(dip,inner=~condition,layout=c(2,2))
after the plot command I obtained this error message:
Error in if(!any(cond.max.level - cond.current.level <0)&&(row-1)* :
missing value where TRUE/FALSE needed
This error only occured in compination with "layout". It was no
2004 Apr 22
1
lme correlation structure error
Hi there fellow R-users,
I am trying to follow an example of modelling a serial correlation structure
in the textbook "Mixed Effects Model in S and Splus".
However, I am getting some very odd results. Here is what I am trying to
run:
library(nlme)
data(Ovary)
fm1<-lme(follicles~sin(2*pi*Time)+cos(2*pi*Time),data=Ovary,random=pdDiag(~s
in(2*pi*Time)))
### The example is fine up
2002 Sep 10
2
Hat values for generalized additive models
Would anyone be able to provide insight for the following question, please?
Setting: estimation of prediction intervals for age-period-cohort models
using GAMs (rate ~ s(age,period))
Method: bootstrap (Davison and Hinkley, 1997)
Issue: standardisation of the residuals for resampling requires an
adjustment using the diagonals of the hat matrix.
Is there a simple way to get the hat values out of a
2011 Mar 18
0
Life of style
it occupies the nerazzurri champions league final win over the psychological advantage, and for bayern speaking, lost the champions league blemish also have hope in February of knockouts compensated, however with seven months at the top of the highest in Europe now compared both teams are suffering a flourishing after the lonely time. After the end of the season, inter milan and bayern Munich are
2007 Oct 01
1
corMatrix crashes R 2.5.1 (windows XP) with corARMA structure
R-helpers,
n <- 100
arcoefs <- c(0.8)
macoefs <- c(-0.6)
p <- length(arcoefs)
q <- length(macoefs)
require(nlme)
tmp <- corARMA(value=c(arcoefs,macoefs), form=~1, p=p, q=q)
Sigma <- corMatrix(tmp, covariate = 1:n) # results in segfault
Have I used these commands in an improper way?
Thanks
Ben
2008 Feb 12
0
nlme & special case of corARMA?
Dear All:
I am trying to fit a special case of a 2-banded Toeplitz correlation
structure. A 2-banded Toeplitz has ones on the diagonal, a
correlation, RHO1, on the first off-diagonal, and a correlation, RHO2,
on the second off-diagonal, with zeros on all subsequent
off-diagonals. After reading relevant sections in Mixed-Effects
Models in S and S-PLUS (Pinheiro & Bates, 2000) and searching
2005 Jun 10
1
Problems with corARMA
Dear all
I am tryiing to fit the following lme with an ARMA correlation structure:
test <- lme(fixed=fev1f~year, random=~1|id2, data=pheno2,
correlation=corARMA(value=0.2, form=~year|id2), na.action=na.omit)
But I get the following error message:
Error in getGroupsFormula.default(correlation, asList = TRUE) :
"Form" argument must be a formula
I have used this same form
2005 Dec 09
1
R-help: gls with correlation=corARMA
Dear Madams/Sirs,
Hello. I am using the gls function to specify an arma correlation during
estimation in my model. The parameter values which I am sending the
corARMA function are from a previous fit using arima. I have had some
success with the method, however in other cases I get the following error
from gls: "All parameters must be less than 1 in absolute value". None
of
2005 Apr 14
1
lme, corARMA and large data sets
I am currently trying to get a "lme" analyses running to correct for the
non-independence of residuals (using e.g. corAR1, corARMA) for a larger data
set (>10000 obs) for an independent (lgeodisE) and dependent variable
(gendis). Previous attempts using SAS failed. In addition we were told by
SAS that our data set was too large to be handled by this procedure anyway
(!!).
SAS script
2003 Jul 09
0
model selection in lme when corARMA is assumed
I have a data analysis job for which lme may be used. Prof. Spencer Graves had helped me much on that. I'm really appreciated for that. Could anybody else in the list give me some hints from other perspectives? I hope I can learn as much as possible for this complicated real data.
Thanks in advance.
Hanhan
To briefly describe my data: My data is health effect measurements (y) and personal
2008 May 04
1
Validating a mixed-effects model
Hi
I constructed a mixed-effects model from longitudinal repeated
measurements of lab values in 22 patients seperated into two groups
with the groups as fixed effect using lme. I thought about using the
jackknife procedure, i. e., removing any one subject and calculating
the fixed effect, to assess the stability of the fixed effect and
thereby validate the model. I suppose this has been done in
2007 Oct 10
2
corMatrix crashes with corARMA structure (PR#9952)
Full_Name: Benjamin Tyner
Version: 2.6.0 RC 2007-10-01 r43043
OS: WinXP
Submission from: (NULL) (171.161.224.10)
platform i386-pc-mingw32
arch i386
os mingw32
system i386, mingw32
status RC
major
2004 Mar 09
2
corARMA and ACF in nlme
Hi R-sters,
Just wondering what I might be doing wrong. I'm trying to fit a multiple
linear regression model, and being ever mindful about the possibilities of
autocorrelation in the errors (it's a time series), the errors appear to
follow an AR1 process (ar(ts(glsfit$residuals)) selected order 1). So,
when I go back and try to do the simultaneous regression and error fit with
gls,
2003 Jul 08
1
Questions about corARMA
Hi,
I'm a new member here in the list. I am a graduate from University of Georgia. Recently in doing analysis using lme on a dataset, I found several questions:
1. How to express the equation when the correlation structure is very complicated. For exmaple, if the fixed is y(t)=0.03x1(t)+1.5x2(t)(I omitted "hat" and others). And the model with corARMA(p=2,q=3) is proper. What will be
2004 Jul 20
1
Performance problem
Dear all,
I have a performance problem in terms of computing time.
I estimate mixed models on a fairly large number of subgroups (10000) using
lme(.) within the by(.) function and it takes hours to do the calculation
on a fast notebook under Windows.
I suspect by(.) to be a poor implementation for doing individual analysis
on subgroups.
Is there an alternative and more efficient way for doing
2004 Jul 21
2
Rose Diagrams
Hi,
Is it possible to create Rose Diagrams of wind data (speed & direction) with
R??
Best regards,
Lars Peters
-----
Lars Peters
University of Konstanz
Limnological Institute
D-78457 Konstanz
Germany
phone: +49 (0)7531 88-2930
fax: +49 (0)7531 88-3533
e-mail: Lars.Peters@Uni-Konstanz.de
web: Lars Peters
<http://www.uni-konstanz.de/sfb454/tp_eng/A1/doc/peters/peters.html>
2003 Dec 03
1
Changing Colors
Hello,
I've got a big problem. I'm using R for geostatistical analyses, especially
the field-package.
I try to generate plots after the kriging process with help of
image.plot(..., col=terrain.colors, ...). Everything works fine, but I want
to reverse the color-palettes (heat.colors, topo.colors or gray()) to get
darkest colors at highest data-values instead the other way round.
Could
2004 Jul 09
1
Mixed model ANOVA with a nested design
Dear all,
I've got a big problem. I try to analyse my data using R with a mixed model
ANOVA without useful results and success.
My data are as follows:
3 factors (Treatment, Site, Subsite) with 'Subsite' as random factor and
nested into 'Site'.
I want to analyse the effects of the three main effects (factorial design to
a specified degrees (2)) with the interactions between