[R] using optimize() correctly ...
Esmail
esmail.js at gmail.com
Sun May 24 02:34:11 CEST 2009
Hi,
I am trying to use the optimize function to optimize a function. The
results I am getting don't agree with what I compute on my own and
when I look at the graph of
f(x) = 100 + ((x-10)**2 + (x-10)) * cos(x-10), where -10 <= x <= 10
in gnuplot.
I suspect I am making a mistake in the usage of the R optimize
function, perhaps someone could point out where?
> f<-function(x) 100 + ((x-10)**2 + (x-10)) * cos(x-10)
to MAXIMIZE:
> result=optimize(f, c(-10,10), lower = -10, upper=10, maximum=TRUE)
> result
$maximum
[1] -2.728743
$objective
[1] 247.3284
to MINIMIZE
> result=optimize(f, c(-10,10), lower = -10, upper=10, maximum=FALSE)
> result
$minimum
[1] 6.290112
$objective
[1] 91.52681
However, I believe the correct values should be
minimize:
x = -5.838 val= -133.020
maximize:
x = -8.957 val= 438.448
Thanks,
Esmail
This is w/ R version 2.8.1 (2008-12-22) under Ubuntu 9.04
More information about the R-help
mailing list