Pessoal, boa tarde! Tenho interesse no tópico e fiz uns testes. Não sei se ajuda em algo, mas deixo o script pra consulta. ### <code r> head(Orange, 3) mForm <- as.formula("circumference ~ A/(1+exp((B-age)/C))"); mForm; class(mForm) mExpr <- mForm[[3]]; mExpr; class(mExpr) # A/(1 + exp((B - age)/C)) fm1 <- nls(mForm, Orange, start=list(A=160, B=700, C=350)) mPar <- summary(fm1)$parameters[,1] xLim <- with(Orange, range(pretty(age))) varx <- all.vars(mExpr)[!all.vars(mExpr) %in% names(mPar)] sapply(1:length(mPar), function(i) {assign(names(mPar)[i], mPar[i], envir=.GlobalEnv)}) eval(call("curve", mExpr, xLim[1], xLim[2], xname=varx)) # curve(A/(1 + exp((B - age)/C)), xLim[1], xLim[2], xname=varx) plot(circumference~age, Orange) eval(call("curve", mExpr, xLim[1], xLim[2], xname=varx, add=T, col=2)) ### </code> ================================================ Éder Comunello Agronomist (UEM), MSc in Environ. Sciences (UEM) DSc in Agricultural Systems Engineering (USP/Esalq) Brazilian Agricultural Research Corporation (Embrapa) Dourados, MS, Brazil |<O>| ================================================ GEO, -22.2752, -54.8182, 408m UTC-04:00 / DST: UTC-03:00