This is not reproducible, so I am reduced to guessing.
Your loglike() is only defined for positive f, but you have not imposed that constraint on your optimization. Further, if f=5.91e-05 is a typical value, your problem is badly conditioned and the finite difference code in optim() is likely to step outside the undeclared region of validity.
I suggest that you - study the help page for optim() - make use of the control parameters to scale the problem suitably - either impose the positivity constraint via the L-BFGS-B method, or transform f to a suitable scale, e.g. by making log(f) the parameter. On Tue, 11 Mar 2008, bernardo lagos alvarez wrote:
Dears useRs, I am using the mle function but this gives me the follow erros that I don't understand. Perhaps there is someone that can help me.
You could look at the many warnings -- they may well tell you the underlying problem.
thank you for you atention. Bernardo.erizo <- read.csv("Datos_Stokes_1.csv", header = TRUE) head(erizo)EDAD TALLA 1 0 7.7 2 1 14.5 3 1 16.9 4 1 13.2 5 1 24.4 6 1 22.5TAN <- function(edad,f,c,a,d) (1/sqrt(f))*log(abs(2*f*(edad-c)+ 2*sqrt((f^2)*((edad-c)^2)+f*a)))+d loglike = function(f,c,a,d) {+ edad <- erizo$EDAD + LT <- erizo$TALLA + N <- length(edad) + sigma <- sum((LT - TAN(edad,f,c,a,d))^2) / N + logl <- (N/2)*log(sigma) + (sum((LT - TAN(edad,f,c,a,d))^2) / (2*sigma)) + }ini.pars <- list(f=5.91e-05,c=-0.41732,a=0.009661,d=846.7179) library(stats4) erizo.mle <- mle(start= ini.pars, minuslogl = loglike, method="Nelder-Mead", control = list(maxit=1500, trace=TRUE))Nelder-Mead direct search function minimizer function value for initial parameters = 1159.477620 Scaled convergence tolerance is 1.72776e-05 Stepsize computed as 84.671790 BUILD 5 3165.307359 1159.477620 . . . HI-REDUCTION 303 1158.377359 1158.377314 LO-REDUCTION 305 1158.377339 1158.377303 LO-REDUCTION 307 1158.377321 1158.377303 Exiting from Nelder Mead minimizer 309 function evaluations used Error en optim(start, f, method = method, hessian = TRUE, ...) : non-finite finite-difference value [1] Además: Hubo 50 o más avisos (use warnings() para ver los primeros 50) ______________________________________________ [email protected] 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.
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