Re: [R] Trouble with optim function

2010-02-18 Thread Ian Fiske
You're minimizing the log likelihood, but you want to minimize the *negative* log likelihood. Also, optimize() is better than optim() if you have a function of only one argument. Replace Jon Moroney wrote: #Create the log likelihood function LL-function(x) {(trials*log(x))-(x*sumvect)}

[R] Trouble with optim function

2010-02-18 Thread Prof. John C Nash
optim really isn't intended for [1D] functions. And if you have a constrained search area, it pays to use it. The result you are getting is like the second root of a quadratic that you are not interested in. You may want to be rather careful about the problem to make sure you have the function

[R] Trouble with optim function

2010-02-17 Thread Jon Moroney
Hi all, I'm trying to make a little script to determine an unknown rate for a number of known exponential trials. My Code: #Set Trials and generate number trials=100 rand-runif(1,0,1) vector=0 #Generate vector of 100 random exponentials and sum them for (i in 1:100) {