[R] Problem with the port algorithm in nls function

[Bert Gunter]

from ?nls ...

"The algorithm = "port" code appears unfinished, and does not even
check that the starting value is within the bounds. Use with caution,
especially where bounds are supplied."

So it appears that you may have gotten what you paid for.

Cheers,
Bert
Bert Gunter

"Data is not information. Information is not knowledge. And knowledge
is certainly not wisdom."
   -- Clifford Stoll


On Mon, Nov 16, 2015 at 10:30 AM, roberto marrone
<robertomarrone at hotmail.it> wrote:
> Dear all,
>
> using the following code I have find a problem with the port algorithm. If I use the nls function without lower bound for my parameter it compute the parameter's value but I want the parameter positive. Running the following code I had this error. Thanks at all.
>
>
> optim <- nls(Prezzo ~ S*pnorm((log(15/14)+(0.015+theta^2/2)*0.17)/(theta*sqrt(0.17))) - 14*exp(-0.015*0-17)*pnorm((log(15/14)+(0.015+theta^2/2)*0.17)/(theta*sqrt(0.17)) - theta * sqrt(0.17)),
> +  start=c(theta=0.1),
> +  data=data,
> +  algorithm="port",
> +  lower=0.01,
> +  trace=TRUE,
> +  control= nls.control(maxiter = 100, tol = 1e-05, minFactor = 1/1024, printEval = FALSE, warnOnly = FALSE))
>
>
> Error in nls_port_fit(m, start, lower, upper, control, trace, give.v = TRUE) :
>   INTEGER() can only be applied to a 'integer', not a 'NULL'
>
>
>         [[alternative HTML version deleted]]
>
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