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About nlminb function

3 messages · Freddy Hernández, Jorge I Velez, Rui Barradas

Freddy Hernández
# 
Hello

I want to use the nlminb function but I have the objective function like
characters. I can summarize the problem using the first example in the
nlminb documentation.

x <- rnbinom(100, mu = 10, size = 10)
hdev <- function(par)   -sum(dnbinom(x, mu = par[1], size = par[2], log =
TRUE))
nlminb(c(9, 12), objective=hdev)

With the last instructions we obtain appropriate results. If I have the name
of the objective function stored in the element name, how can modify the
next two instructions to obtain the same above results?

name <- 'hdev'
nlminb(c(9, 12), objective=name)

Thanks for the reply.

Freddy.

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Rui Barradas
# 
Hello,

Try


makeFunction <- function(x) eval( parse(text=x) )

name <- 'hdev'
nlminb(c(9, 12), objective = makeFunction(name))

Hope this helps,

Rui Barradas

Em 04-07-2012 17:37, Freddy Hern?ndez escreveu: