Hi Luigi, I took a quick look. First error: You wrote O = mle2(minuslogl = holling, start = list(a = A, h = B, x = X))
it should be b=B (h is not an argument of holling()) The error message gave very precise information! Second error: You wrote O = mle2(minuslogl = nll, start = list(a = A, h = B), data = list(n = 57200000, k = A)) but the arguments to nll() are p,n,k. Setting start to values for a and h causes the function to complain. HTH, Eric On Tue, Jun 30, 2020 at 12:45 PM Luigi Marongiu <marongiu.lu...@gmail.com> wrote: > > Hello, > I would like to optimize the function: > ``` > holling = function(a, b, x) { > y = (a * x^2) / (b^2 + x^2) > return(y) > } > ``` > I am trying to use the function mle2 from bbmle, but how do I need to > feed the data? > If I give `holling` as function to be optimized, passing the starting > values for `a`, `b`, and `x`, I get: > ``` > X = 1:60 > A = 3261 > B = 10 > O = mle2(minuslogl = holling, start = list(a = A, h = B, x = X)) > > Error in mle2(minuslogl = holling, start = list(a = A, b = B, x = X)) : > some named arguments in 'start' are not arguments to the specified > log-likelihood function > ``` > If I pass the negative log-function (assuming a binomial distribution > of the data, which I am not sure about) > ``` > nll = function(p, n, k) { > # extract parms > a = p[1] > h = p[2] > # calculate probability of attack > pred = a/(1+a*h*n) > # calc NLL > -sum(dbinom(k, prob = pred, size = n, log = TRUE)) > } > ``` > then I get the same error: > ``` > > O = mle2(minuslogl = nll, start = list(a = A, h = B), > + data = list(n = 57200000, k = A)) > Error in mle2(minuslogl = nll, start = list(a = A, h = B), data = > list(n = 57200000, : > some named arguments in 'start' are not arguments to the specified > log-likelihood function > ``` > but with the disadvantage of working on an assumed function (nll). > How can I optimize the function `holling` properly? > Thank you > > > > > -- > Best regards, > Luigi > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.