Hello,
Thanks a lot for the replies.
I tried to use the "optim" function in R, and chose the "L-BFGS-B" method
of optimization. Now the result is very sensitive to the starting values. I
use the same function, but I give the line of code I use for "optim".
optim(0.25, f, method= "L-BFGS-B", low
lap tibco.com
> -Original Message-
> From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On
> Behalf
> Of William Dunlap
> Sent: Monday, October 28, 2013 3:03 PM
> To: Rolf Turner; Shantanu MULLICK
> Cc: r-help@r-project.org
> Subject: Re: [R] O
, 2013 2:01 PM
> To: Shantanu MULLICK
> Cc: r-help@r-project.org
> Subject: Re: [R] Optimize function in R: unable to find maximum of logistic
> function
>
>
> This could be described as a bug, perhaps. Or it could be described as
> an indication that numerical optimization
This could be described as a bug, perhaps. Or it could be described as
an indication that numerical optimization is inevitably tricky. Notice that
if you narrow down your search interval from [0,5] to [0,0.5] you get the
right answer:
> optimize(f, c(0, 0.5), maximum= TRUE,tol=1e-10)
$maximum
[
Hello,
This seems like a bug, removing 'maximum = TRUE' has no effect except
that the returned value says it's a minimum, not a maximum.
Rui Barradas
Em 28-10-2013 17:00, Shantanu MULLICK escreveu:
Hello Everyone,
I want to perform a 1-D optimization by using the optimize() function. I
want
Hello Everyone,
I want to perform a 1-D optimization by using the optimize() function. I
want to find the maximum value of a "logistic" function. The optimize()
function gives the wrong result.
My code:
f= function (k) {
T_s = 20
result = (2- 2/(1+ exp(-2*T_s*k)))
return(result)
}
optimize(f, c(0
6 matches
Mail list logo
