similar to: GLS with nlme

Dear List: I am estimating a gls model and am having to make some rather unconventional modifications to handle a particular problem I have identified. My aim is to fit a GLS with an AR1 structure, obtain the variance-covariance matrix (V), modify it as needed given my research problem, and then reestimate the GLS by brute force using matrix operations. All seems to be working almost perfectly,

Hello, I'm trying to assess the similarity of two lines that are represented as points (output of differential equation solvers). Is there a function or a package that deals with things like this? Thanks, John. ==================================================== Johannus (John) Janmaat Assistant Professor of Economics Barber School of Arts and Sciences University of British Columbia -

Dear All, Thank you for the replies to my first thread here: http://r.789695.n4.nabble.com/global-optimisation-with-inequality-constraints-td3799258.html. So far the best result is achieved via a penalised objective function. This was suggested by someone on this list privately. I am still looking into some of the options mentioned in the original thread, but I have been advised that there may

Hi there, I have a question on how to extract the linear term in the penalized spline in coxph. Here is a sample code: n=100 set.seed(1) x=runif(100) f1 = cos(2*pi*x) hazard = exp(f1) T = 0 for (i in 1:100) { T[i] = rexp(1,hazard[i]) } C = runif(n)*4 cen = T<=C y = T*(cen) + C*(1-cen) data.tr=cbind(y,cen,x) fit=coxph(Surv(data.tr[,1],

Hi I have some panel data for the 50 US states over about 25 years, and I would like to test a simple model via OLS, using this data. I know how to run OLS in R, and I think I can see how to create Panel Corrected Standard Errors using http://jackman.stanford.edu/classes/350C/pcse.r What I can't figure out is how to correct for autocorrelation over time. I have found a lot of R stuff on

Hello All, Is there a fast way to find the index(row and column) of a point in a matrix? Thanks, John. -- -------------------------------------------------------------------------- Dr. John Janmaat Department of Economics, Acadia University, Wolfville, NS, B4P 2R6 E-mail: jjanmaat at acadiau.ca Web: http://ace.acadiau.ca/~jjanmaat Tel: 902-585-1461 Fax: 902-585-1070

Hello, I have a system of quadratic equations (results of a Hamiltonian optimization) which I need to find the roots for. Is there a package and/or function which will find the roots for a quadratic system? Note that I am not opimizing, but rather solving the first order conditions which come from a Hamiltonian. I am basically looking for something in R that will do the same thing as fsolve in

Hello, I'm playing around with cluster analysis, and am looking for methods to select the number of clusters. I am aware of methods based on a 'pseudo F' or a 'pseudo T^2'. Are there packages in R that will generate these statistics, and/or other statistics to aid in cluster number selection? Thanks, John. --

Hello All, I am drawing four contour plots on a 2x2 layout. I need to downsize the contour line labels. cex and labcex do not seem to work. Any suggestions? Thanks, John. -- -------------------------------------------------------------------------- Dr. John Janmaat Department of Economics, Acadia University, Wolfville, NS, B4P 2R6 E-mail: jjanmaat at acadiau.ca Web:

Hello, Is there a package that implements the Cochrane-Orcutt itterative procedure for dealing with autocorrelation in a regression model? Thanks, John. -- ========================================== John Janmaat Department of Economics Acadia University, Wolfville, NS, B0P 1X0 (902)585-1461 All opinions stated are personal, unless otherwise indicated.

In order not to forget it (I have not got any answer so far) ... Uwe Ligges -------- Original Message -------- Subject: plotmath in underlined style; was: Re: [R] Underline in expression(). Date: Sun, 26 Sep 2004 18:50:02 +0200 From: Uwe Ligges <ligges@statistik.uni-dortmund.de> Organization: Fachbereich Statistik, Universitaet Dortmund To: John Janmaat <jajanmaat@netscape.net>,

Hello All, Is there an analogue to \underbar or the AMS math \underline in graphical math expressions? Thanks, John. -- ===================================================================================== Dr. John Janmaat Department of Economics Acadia University Wolfville, Nova Scotia, Canada B4P 2R6 TEL: 902-585-1461 WWW: http://ace.acadiau.ca/~jjanmaat/ EMAIL: jjanmaat at acadiau.ca June

Hello All, I'm looking to test a variable in a logit model (glm(..., binomial(link="logit"))) for exogeneity (endogeneity). At this point I am planning to try implementing Jeffery Grogger's "A Simple Test for Exogeneity in Probit, Logit, and Poisson Regression Models", Economic Letters, 1990. To do this, I need to be able to do an instrumental variables NLS

Hello, I am trying to get a time derivative on a plot title. I prefer to have it in the form \dot{s_i}, but \partial s_i/\partial t would be O.K. In the graphics demo I cannot find either a dot or a partial equivalent. Thanks, John. -- ========================================== John Janmaat Department of Economics Acadia University, Wolfville, NS, B0P 1X0 (902)585-1461 All opinions stated

Hi all, Xiph aims at developing open-standards media formats. Though xiph.org tells about vorbis/theora/flac/speex, nothing is mentioned about container to use (that is ogg/ogm). I have a few questions Is there a difference between ogg and ogm? I guess its only the extension that is different and everything else is same. Some tools (like ogmtools) are available to create ogm files. What is

Dear all, For analysis of a longitudinal data set with fixed measurement in time I built a gls model (nlme). For testing hypotheses in this model I used the linear.hypothesis function from the car package. A check with the results obtained in SAS proc MIXED with a repeated statement revealed an inconsistency in the results. The problem can be that the linear.hypothesis function (1) only gives the

Hi all, I would like to know how the BIC criterion is calculated for models estimated using gls( ) function. I read in Pinheiro & Bates (2000) p84 that BIC = -2logL + npar*log(N) (for the ML method), or BIC = -2logLR + npar*log(N-p) (for the REML method) but when I use any of these formulae I don't obtain the result given by R. Thanks in advance for any help. Eve CORDA Office national

Dear R Gurus, How do I generate/obtain the 95% CI of the predicted values from the GLS model? "Not plot.Predict" Currently I know how to get the 95% CI for the GLS model parameters. Please advice Regards Peter South Africa Please Note: This email and its contents are subject to our email legal notice which can be viewed at http://www.sars.gov.za/Email_Disclaimer.pdf

Hi I get the following error when I try and get the AICc for a gls regression using qpcR: > AICc(gls1) Loading required package: nlme Error in n/(n - p - 1) : 'n' is missing My gls is like this: > gls1 Generalized least squares fit by REML Model: thercarnmax ~ therherbmax Data: NULL Log-restricted-likelihood: 2.328125 Coefficients: (Intercept) therherbmax 1.6441405

Dear Rers, I have threes series, x, y, z and I want to fit a model z ~ x + y. First of all, I fit a lm. I found the residuals are correlated, by looking at the acf() and pacf(). Then I tried to fit a gls model allowing residuals to be correlated (correlation = corARMA(p=5, q=1)): y.na <- as.data.frame(y[complete.cases(y),]) y.gls <- gls(z ~ x + y, data = y.na, correlation=corARMA(p=5,