search for: nlmest

...imulate 1000 data from nonlinear model in order to be able to do mixed effect analysis. If the program works but give you following warning message, what should I do? Can I still accept the result, which is about the precision of model parameter estimation? FALSE CONVERGENCE. in: ms( ~ - logLik(nlmeSt, nlmePars), start = list(nlmePars = c(coef(nlmeSt))), control = .... SINGULAR CONVERGENCE. in: ms( ~ - logLik(nlmeSt, nlmePars), start = list(nlmePars = c(coef(nlmeSt))), control = .... Thanks Farinaz

...id/set, weights=varPower(fixed=1)) (mydata has over 1000 records, so I won't reproduce it here). When I run this, I get the error: Error: dim<- length of dims do not match the length of object It turns out the error is being thrown by the statement: dim(work$pdFactor) <- dim(pdMatrix(nlmeSt$reStruct[[1]])) indeed: Browse[1]> length(work$pdFactor) [1] 72 Browse[1]> dim(pdMatrix(nlmeSt$reStruct[[1]])) [1] 6 6 It looks like work$pdFactor contains information about both levels of nesting, which is being ignored. Does someone have an idea for a fix (or am I abusing nlme)? I'...

...-------------------- > nlme(Count ~ quad.PBMC.model(aL, aN, T0), + data = tissueData, + weights = varConstPower(form =~ Count), + start = list( fixed = c(rep(1000, 8), -2, -2) ), + fixed = list(T0 ~ TypeTissue-1, aL ~ 1, aN ~ 1), + random = aL + aN ~ 1|Tissue + ) Error in MEestimate(nlmeSt, grpShrunk) : Singularity in backsolve at level 0, block 1 > > --------------------------------------------- The above command clearly this doesn't work, but if I comment out the "weights = ..." line, it executes with no problem. I'd greatly appreciate any guidance on h...

...96, 2.60583067635322, -0.638495324795519, -0.137018044847307, 1.70105176178795, -3.07372462709182, -0.0445309584408364, 12.3518546784787, -3.22126648052618, -1.69049623029482, 0.907261039321137)) 5: .C(fit_nlme, thetaPNLS = as.double(c(as.vector(unlist(sran)), sfix)), pdFactor = as.double(pdFactor(nlmeSt$reStruct)), as.integer(unlist(rev(grpShrunk))), as.integer(unlist(Dims)), as.integer(attr(nlmeSt$reStruct, "settings"))[-(1:3)], as.double(cF), as.double(vW), as.integer(unlist(cD)), settings = as.double(pnlsSettings), additional = double(NReal * (pLen + 1)), as.integer(!is.null(corre...

...Specifically, there a way to return an nlme object when the estimation process runs into a singular matrix? For example, can the results up to the point of an error such as "Error in solve.default(pdMatrix(a, fact = TRUE)) : system is computationally singular" or "Error in MEestimate(nlmeSt, grpShrunk) : Singularity in backsolve at level 0, block 1\n" be returned rather than only an error message being returned? Setting the "returnObject" nlme control option to TRUE seems to return an nlme object only when the maximum number of iterations is reached without meeting the...