Hello!
I am getting the following errors when running optim() [I tried optim() with 3 different methods as you can see]: Error in optim(c(0.66, 0.999, 0.064), pe, NULL, method = "L-BFGS-B") : objective function in optim evaluates to length 6 not 1 > out <- optim( c(0.66, 0.999, 0.064), pe, NULL, method = "Nelder-Mead") Error in optim(c(0.66, 0.999, 0.064), pe, NULL, method = "Nelder-Mead") : objective function in optim evaluates to length 6 not 1 > out <- optim( c(0.66, 0.999, 0.064), pe, NULL, method = "CG") Error in optim(c(0.66, 0.999, 0.064), pe, NULL, method = "CG") : objective function in optim evaluates to length 6 not 1 I don't know what the error message should mean to me. Particulars for the problem are listed below. Thanks in advance for any help!! Stu > y <- c(0.111111111111111,0.0921052631578947,0.0564516129032258,0.0608108108108108 ,0.0128205128205128,0.0136078431372549) > x3 <- c(3600,169200,185400,255600,271800,342000) > x2 <- c(1,3,4,5,6,7) > x1 <- c(0,0.978723404255319,0.087378640776699,0.549295774647887,0.0596026490066225 ,0.61578947368421) > observs <- data.frame(y, x1, x2, x3) > attach(observs) > pe <- function(c) c[1]*x1*x2^c[2]*x3^c[3] > out <- optim(c(0.66, 0.999, 0.064), pe, NULL, method = "L-BFGS-B") [[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.