Hello everyone... We were trying to implement the Newton-Raphson method in R, and estimate the parameters a and b, of a function, F, however we can't seem to implement this the right way. Hope you can show me the right way to do this. I think what we want R to do is to read the data from the website and then peform maxNR on the function, F. Btw the version of R being used is "RGui for Windows" if it helps to know this.
R-code below: library(maxLik) > require(maxLik) > > x <- > read.table('http://www.math.ku.dk/kurser/2008-09/blok4/stat2/doku/data/Eksempel_6_3.txt', > header = TRUE); > t <- log(x$Koncentration); > X <- x$Status; > > p <- function(a,b) exp(a+b*t)/(1+exp(a+b*t)); > S <- sum(X); > SP <- sum(t*X); > > F <- function(a,b) { + c(sum(p(a,b)) - S, + sum(t*p(a,b)) - SP) + } > > > z <- maxNR(F, start=1, print.level=2) Error in p(a, b) : element 1 is empty; the part of the args list of '*' being evaluated was: (b, t) > Thanks and best regards. -- View this message in context: http://n4.nabble.com/maxNR-Error-in-p-a-b-element-1-is-empty-the-part-of-the-args-list-of-being-evaluated-was-b-t-tp1677790p1677790.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.