search for: corclasses

...rCAR1 and corExp (among other options) to model the temporal and spatial components of the auto-correlation. However, as far as I can tell, I can only model using one correlation class or the other. I would like my model to account for both temporal and spatial autocorrelation simultaneously. The ?corClasses help page provides some advice on how to create your own correlation class. I was able to create a new class that I called corSPT: I add the spatial and temporal autocorrelation matrices to produce the corSPT correlation matrix. The code for this is pasted below: ################## BEGIN ########...

...to link from within parts of the documentation that are not the \seealso section? For example, I would like to have something like: \arguments{ \item{correlation}{an optional \code{corStruct} object describing the within-group correlation structure; the available classes are given in \link{\code{corClasses}}} } When the package is compiled, the word corClasses is blue and underlines, but nothing happens when you click on it. Second, how do I link to a function of the same name in another package? I thought I could use something like: \seealso{\code{\link[nlme]{ranef}}} but that gives a Page Not F...

Let's say I would like to look inside the function corBrownian in library (ape). When I type in the function name I get the following, which is not nearly the detail that goes into this function. I am wondering how to begin cracking this function open (and others) so I can learn more about it and perhaps code my own corClass one day. Thanks. > corBrownian function (value = 1, phy, form

I noticed that ?corClasses in package nlme does not list corSpatial among the standard classes. This might either be intentional because corSpatial is not "standard" , or it might be simply an oversight that needs correcting. ------------------------------------------ Robert W. Baer, Ph.D. Professor of Physiolog...

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,

Hi, I need to correct for ar(1) behavior of my residuals of my model. I noticed that there are multiple gls models in R. I am wondering if anyone has experience in choosing between gls models. For example, how should one decide whether to use lm.gls in MASS, or gls in nlme for correcting ar(1)? Does anyone have a preference? Any advice is appreciated! Thanks, -- Tom [[alternative HTML

A couple of questions: How to be sure that gls allowes errors to be correlated and/or have unequal variances? (is this on auto or is there a switch?) How to calculate confidence limits for a linear regresssion? -------------- next part -------------- A non-text attachment was scrubbed... Name: dthompson.vcf Type: text/x-vcard Size: 303 bytes Desc: Card for David Thompson Url :

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

dear list, I am wondering if one can find examples and/or more detailed descriptions of modifications needed when going beyond standard corStruct classes (i.e. those already provided for use in lme/nlme)? When I looked at pages 238-239 of Pinheiro/Bates (2000): Mixed-effects models in S and S-plus, I found that I would need a bit more explicit guidance what to do for implementing a new

Hi! I have a dataset of properties that are owned by different firms, each firm owning multiple properties. I am running a regression of holding period (how long a property was held in a firm's portfolio) on the left, and a bunch of factors on the right. When calculating standard errors, I would like to cluster my disturbance terms by firm. Any ideas on how to do this? I'm guessing

I would like to be able to extract the significance levels (or standard errors) of the variance-covariance parameters in nlme objects (i.e. from the varClasses and/or corClasses). Is there a way to do it, or do I have to reverse the intervals function calculations ? Thanks. Rob _________________________________________________________________ [[alternative HTML version deleted]]

Hi to all, In other statistical software, such as Eviews, it is possible to regress a model with the Least Squares method, assuming that the residuals follow an AR(q) process. For example the resulting regression is something like y = 1.2154 + 0.2215 x + 0.251 AR(1) How is it possible to do the same in R? Thank you very much in advance, Constantine Tsardounis http://www.costis.name

Dear R help-list reader, I'm trying to investigate my data with linear mixed model and are seeking advise how to write the model in R. I was trying to get hold of the recommended book from Bates et al, but neither the major bookshop nor our university library had the book. My data is mirroring the example given in the appendix of John Foxes book "Applied Regression" with a

Dear R-users: I have some problems working with lme function, and i would be glad if anyone could help me. this kind of analysis i was used to do with PROC MIXED from SAS, but i would like to move to R, for many reasons... So, the problem is: Imagine the I have 3 factors: fact_A, fact_B and fact_C: The latter I would assume that is random, and the rest of them are fixed. Analysing the

Dear List, This is my first post, and I'm a relatively new R user trying to work out a mixed effects model using lme() with random effects, and a correlation structure, and have looked over the archives, & R help on lme, corClasses, & etc extensively for clues. My programming experience is minimal (1 semester of C). My mentor, who has much more programming experience, but a comparable level of knowledge of R, has been stumped. What follows are 3 questions pertaining to an lme() model, one on the nested hierarcy, 1 on a st...

I have been reading about autocorrelation in linear models over the last couple of days, and I have to say the more I read, the more confused I get. Beyond confusion lies enlightenment, so I'm tempted to ask R-Help for guidance. Most authors are mainly worried about autocorrelation in the residuals, but some authors are also worried about autocorrelation within Y and within X vectors

R 2.8.1 Windows XP I am trying to analyze repeated measures data (the data are listed at the end of this Email message) and I need help to make sure that I have properly specified my model, and would like to know why lmer does not return a p value for Group, my fixed effect. My subjects are divided into two groups (variable GROUP), individual subjects are indicated by the variable SS, Value is