Hi: Is equation written as a function? As in, say,
eq <- function(k) 1/LR - (exp(-k * T) * LM) * (1 - exp(-k)) I believe the log of the likelihood would be a simpler expression to maximize... On Fri, Oct 1, 2010 at 1:39 PM, <mlar...@rsmas.miami.edu> wrote: > I am trying to figure out how to run maximum likelihood in R. Here is my > situation: > > I have the following equation: > equation<-(1/LR-(exp(-k*T)*LM)*(1-exp(-k))) > This is a numeric vector, given LR, T, LM and k. If this is supposed to be a function of k, then you have to define it as such. See above. > > LR, T, and LM are vectors of data. I want to R to change the value of k > to maximize the value of equation. > > My attempts at optim and optimize have been unsuccessful. Are these the > recommended functions that I should use to maximize my equation? > > With optim I wanted the function to be maximized so I had to make the > fnscale negative. Here is what I put: > > L<-optim(k,equation,control=(fnscale=-1)) > > My result: Error: could not find function "fn" > > This is because equation is not a function, given the definition you provided above. > > Here is what I put for optimize: > > L<-optimise(equation,k,maximum=TRUE) > > My result: Error: 'xmin' not less than 'xmax' > > Any advise would be greatly appreciated. > HTH, Dennis Mike > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
