Simple optim - question
Carsten Steinhoff <carsten.steinhoff <at> gmx.de> writes:
I want to find the parameters mu and sigma that minimize the following
function.
It's important, that mu and sigma are strictly positive.
-----------------
optimiere = function(fmean,smean,d,x,mu,sigma)
{
merk = c()
for (i in 1:length(d))
merk=c(merk,1/(d[i]^2)*(d[i]-1/(fmean*(1-plnorm(x[i],mu,sigma))))^2)
return(sum(merk))
}
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.... Try optim or nlminb, both can be used with constraints. Or, as your example looks like a least-square problem, reformulate optim and use nls. Dieter