similar to: Covariance structure determination when lmer has false convergence.

Dear R Community! We analyse the impact of climbing activity on cliff vegetation. During our fieldwork, we recorded 90 Transects in 3 climbing sites. The aim is to see, if the plant cover (response: Cover) is influenced only by crevice availability (predictor: Cracs), or, additional, by the distance to the climbing route (predictor: Distance). Six plots are nested within one Transect

I am running the lmer() command in a for loop and occasionally a particular iteration is producing the false convergence warning. I would like to be able to mark these iterations with a dummy variable, but I can't find any other notification besides the warning message, which, in a for loop, only is printed after the loop is finished (which does not allow me to see which iteration it happened

Hello, I've run 7 candidate models using mixed-effects logistic regression with the lmer function from the lme4 package, and I'm getting the following error for 5 of those models: Warning message: In mer_finalize(ans : false convergence (8). The candidate models all run with the same data, just slightly different formulas (for AIC model selection). Can anyone explain this error to

Dear All, I am working with a generalized linear mixed-effects model with poisson error using the lme4 package in R. I created a model with the lmer function including some main effects, three two way interactions and two random effects. The model works well, but I have troubles when removing on of the two-way interactions. The Warning message: "In mer_finalize(ans) : false convergence

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 R Users, I was hoping for some help with a recurrent error message in lmer. I am trying to model the effect of temperature on metabolic rate in animals (response = int.length) at different temperatures (mean.sst), with repeated measurements on the same individuals (random effect = female). Ideally I would make a random slope and intercept model where the rate can change differently with

Dear R users, I am trying to fit a GLMM to the following dataset; tab a b c 1 1 0.6 199320100313 2 1 0.8 199427100412 3 1 0.8 199427202112 4 1 0.2 199428100611 5 1 1.0 199428101011 6 1 0.8 199428101111 7 0 0.8 199527103011 8 1 0.6 199527200711 9 0 0.8 199527202411 10 0 0.6 199529100412 11 1 0.2 199626201111 12 2 0.8 199627200612 13 1 0.4 199628100111 14 1 0.8

Hi R-users: New to R and I am trying to run a GLM with random effects. I have 3 replicates ('Replicate) of counts of parasites ('nor.tot.lep') before and after an experiment ('In.Out'). When I run lmer I get the error messages (16 of each) below... > lmer(nor.tot.lep ~ In.Out + (In.Out|Replicate),data=coho, family =tweedie(var.power = 1, + link.power = 1)) Generalized

Hello, all, I am running some simulations to estimate power for a complicated epidemiological study, and am using lme and lmer to get these estimates. I have to run a few thousand iterations, and once in a great while, an iteration will create fake data such that the model won't converge. I see from Google searches that this is not an uncommon situation. My question: is there a way to

Hello, has someone written by chance a function to extract the variance-covariance matrix from a lmer-object? I've noticed the VarCorr function, but it gives unhandy output. Regards, Roel de Jong

I'm trying to create a 3D plot using wireframe with certain parts removed. I would like to get rid of the part of the outer cube that crosses over the plot leaving the back two walls and the axes. It would also be useful to put lines in the plot separate from the wireframe call. I've looked through the documentation and have not been able to find such a request. Here is my code

Hi, I am doing a binomial GLMM with a random intercept using the formula below, but I always get the same warning message. > m01 <- lmer(pres~ HT + DN + dtree + DNm + cmnhi + cmxes + cplan + craan + lfphal0100 + lfov0100 + lfop0100 + (1|plot), family=binomial, data=vphal, verbose=TRUE) 0: 6309.9448: 0.459924 -5.20747 -0.378722 0.558779 -0.200922 -0.0488451 -0.397844 0.367916 -2.09820

I am trying to duplicate the example by Spencer Graves in the wiki, using lmer with the Nozzle data. http://wiki.r-project.org/rwiki/doku.php?id=guides:lmer-tests However the Chisq value and the fitAB values that are calculated are different compared to those in the example. I also get a warning message when I attempt the fitAB. Does anyone have any guidance as to why this might happen and how

Dear list members, the following hlm was constructed: hlm <- groupedData(laut ~ design | grpzugeh, data = imp.not.I) the grouped data object is located at and can be downloaded: www.anicca-vijja.de/lg/hlm_example.Rdata The following works: library(nlme) summary( fitlme <- lme(hlm) ) with output: ... AIC BIC logLik 425.3768 465.6087 -197.6884 Random effects:

Hi all, I've searched threads and read up on some ways of doing this but I'm having a hard time to get it to work. Here's my basic problem. I have the following linear mixed model y = Xb+Zu+e where u~N(0,s^2*K) where K is a matrix. I read a thread that basically suggested to decompose Zu into ZPD^(1/2) D^(-1/2)P'u so that (D^(-1/2)P'u)~N(0,s'^2I) but I'm not sure

Hi, To simplify, suppose I have 2 observations each day for three days. I would like to define the correlation structure of these 6 observations as follows: the correlation of 2 observations on the same day is, say, alpha, the correlation for 2 observations one day apart is rho and the correlation for 2 observations 2 days apart is rho^2. I.e. I would like to have an AR1 correlation + a

Hi R community! I've fitted three mixed-effects regression models to a thousand bootstrap samples (case-resampling regression) using the lme4 package in a custom-built for-loop. The only output I saved were the inferential statistics for my fixed and random effects. I did not save any output related to the performance to the machine learning algorithm used to fit the models (REML=FALSE).

Dear colleagues, I have a data from a repeated measures design that I'm analysing through a mixed model. Nine independent sampling units (flasks with culture medium with algae) were randomly divided into 3 groups ("c", "t1", "t2"). There is no need for inclusion of the random effect of the intercept, because the nine sample units are homogeneous among each other

Hi all, I’m hoping someone might be able to help me out. Forgive me if my mistake is something simple. I am new to mixed models, new to R, and new to lme4 and am struggling to figure everything out. I have two questions that I am hoping someone can answer. 1) Am I using the correct random structure for my model? 2) Can someone help me figure out what is wrong with my syntax to code for random

Dear R users, I am trying to use tseries' garch function in order to determine the volatility of a return series generated by quantmod. Here is the code that I am using: > library(quantmod) > getSymbols("AAPL") convert daily closing prices into continuous log returns > dret<-dailyReturn(AAPL,type='log') check to see that the autocorrelations decay >