similar to: nlme problems

I am trying to plot multiple densityplots on each panel, and using panel.groups to do some additional plotting (not included in the example) as in this example. library(lattice) thedata <- data.frame(x=rnorm(1200),class=rep(1:3,each=200,times=2), group=rep(1:2,each=100,times=6)) densityplot(~x | class,groups=group, xlab='x', panel.groups =

Hello all. I'm doing a simulation study where I will be making use of the 'nlme' package. I want to loosen up the convergence criteria so that I increase the likelihood of convergence (potentially at the cost of obtaining slightly less than ideal results). The parameters in the function nlmeControl() control the convergence criteria. These default values can be modified to make

Dear Splus and R users: I have a problem in fitting a NLME model, the error message is: "step halving factor reduced below minimum in PNLS step" What does it mean and how to fix the problem, could anyone help me about it? Any suggestion/help would be greatly appreciated. Mei

In some trial simulation work I need to create batch files that will repeatedly generate pseudoreplicate datasets and then create non- linear mixed effects models using nlme. Inevitably these models sometimes fail to converge but I need the batch file to simply move on to another simulation rather than abort. I am using the try() function as in model<-try((nlme(...))) which handles

I wonder whether R has methods for constrained fitting of linear models. I am trying fm<-lm(y~x+I(x^2), data=dat) which most of the time gives indeed the coefficients of an inverted parabola. I know in advance that it has to be an inverted parabola with the maximum constrained to positive (or zero) values of x. The help pages for lm do not contain any info on constrained fitting. Does anyone

Hi, I'm trying to get a toy program making use of nmmin to run successfully. I've gotten to the point of compiling. However, when I attempt to run my executable, I guess a bus error. I see that someone else has asked about using nmmin before <http://tolstoy.newcastle.edu.au/R/help/06/03/23944.html>, but I haven't come across any replies. Is there some documentation on how to

Hi I have found some postings referring to the fact that one can try and understand why a particular model is failing to solve/converge from the verbose output one can generate when fitting a nonlinear mixed model. I am trying to understand this output and have not been able to find out much: **Iteration 1 LME step: Loglik: -237.4517 , nlm iterations: 22 reStruct parameters: subjectno1

I am having trouble fitting correlation structures within nlme. I would like to fit corCAR1, corGaus and corExp correlation structures to my data. I either get the error "step halving reduced below minimum in pnls step" or alternatively R crashes. My dataset is similar to the CO2 example in the nlme package. The one major difference is that in my case the 'conc' steps are

I am trying to use the R API to call optim functions (nmmin, vmmin, lbfgsb, etc.) through a C program but I couldn't find the shared library to link under the R-2.6.0 build which is compiled under Linux (REL5). main.cpp:35: undefined reference to `Rf_initEmbeddedR(int, char**)' main.cpp:41: undefined reference to `nmmin' Thanks in advance for any help. ------------------------

Can anybody, please, explain me how many parameter are estimated using randomLCA? For examples, model "dentistry.lca2random" estimate 1 scale (or variance, b_j) parameter and 2 position parameters (a_cj)? Doesn't it? Do I need at least 4 diagnostic tests for such a model? What happens if I specify options blocksize and byclass? How many diagnostic tests (or rater) I need?

Dear Members of the Help List, Honestly, I feel a little bit stupid - I would like to do something rather simple: fit a non linear model to existing data, to be more precise I wanted to start with simple higher order polynomials. Unfortunately, I do not quite understand the examples in the helpfiles for the nlm, nls and nlsModel commands. Could anyone please provide a simple example to get me

Dear R users, I am struggling to fit expo-linear equation to my data using "nls" function. I am always getting error message as i highlighted below in yellow color:  Theexpo-linear equation which i am interested to fit my data:       response_variable =  (c/r)*log(1+exp(r*(Day-tt))), where "Day" is time-variable my response variable rl <-

Hi R-help; In using nlme, I often encounter the following error message: Error in nlme.formula(model = response ~ ......, data = ... : Step halving factor reduced below minimum in PNLS step Resetting the pnlsTol default value does not solve the problem. Any suggestions or workarouds for solving the problem? TIA, Richard

Hello,   I am attempting to use nlme to model the response of 19 groups.  I am able to get a reasonable fit of all of the groups to the observed data using an exponential decay model (a*exp-x*b).  The problem is that when I plot the fitted values to residuals, it demonstrates a pattern of increasing variance.   I attempt to model this variance using   Sig3.nlme <- update(Sig2.nlme, weights =

OS: Arch Linux (64-bit) (fully updated) GFX Card: Geforce 8800GT (driver version irrelevant - had problem for a year) WM: Openbox Problem: Whenever I minimise WoW, the fps drops to sub-10. I can solve this by minimising and maximising the window again, but if I wait too long after minimising, it doesn't always work. Also, if I minimise it by accident too many times, it also doesn't work.

Hey there, I want to plot 5 parabola functions, which happen to be f(x) = 0.25x? + 6,47x -32.6 g(x)=0.99x? -6x -195 j(x)= 0.77x? +14x -495 k(x)=0.001x? + 65x -785 l(x) = 0.9x? -2x -636 in the same graph. Sadly I even do not really understand how to plot just one graph... I found this code in the Internet, which plots a cos-function: >x <- seq( -10, 10, length = 1000) >plot(x,

Hello, how are writes distributed as the free space within a pool reaches a very small percentage? I understand that when free space is available, ZFS will batch writes and then issue them in sequential order, maximising write bandwidth. When free space reaches a minimum, what happens? Thanks! :) -- Regards, Jeremy

Full_Name: Karsten Krug Version: 2.4.0 OS: Open Suse 10.0, Windows XP Submission from: (NULL) (88.134.13.50) I found a problem in the 'optimise' function for one dimensional optimisation. Example 1: Try to find a maximum of the function below with the use of 'optimise' in the interval [0,0.5]. The function follows a parabola and has two local maxima located at the margins of

Hi, I was wondering if someone could please help me. I am doing a logistic regression to compare size at maturity between 3 seasons. My model is: fit <- glm(Mature ~ Season * Size - 1, family = binomial, data=dat) where Mature is a binary response, 0 for immature, 1 for mature. There are 3 Seasons. The Season * Size interaction is significant. I would like to compare the size at 50%

Dear R-users, I need to use the aftreg function in package 'eha' to estimate failure times for left truncated survival data. Apparently, survreg still cannot fit such models. Both functions should be fitting the accelerated failure time (Weibull) model. However, as G?ran Brostr?m points out in the help file for aftreg, the parameterisation is different giving rise to different