R help - Jul 2009 - maximum/minimum value of a function

Dear All,

Does anyone know how to get the maximum/minimum value of a function using R,

I think there should be an instruction, but i can not find it in help files

Thank you in advance for your help :)

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Hi Derek,

like this?

myfunction<-function(xmin, xmax, number_of_values)
 {
 xvalues<-seq(from=xmin, to=xmax, by = ((xmax - xmin)/(number_of_values -
1)))
 outputvalues<-xvalues^2+(xmax/xvalues)^3*runif(number_of_values)
 return(outputvalues)
 }
my.values<-myfunction(1,10,100)
min(my.values)
max(my.values)
plot(my.values)
bests

milton



On Fri, Jul 10, 2009 at 11:11 PM, Derek An <derekan2@gmail.com> wrote:
> Dear All,
>
> Does anyone know how to get the maximum/minimum value of a function using
> R,
>
> I think there should be an instruction, but i can not find it in help files
>
> Thank you in advance for your help :)
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
>
http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>
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On Sat, Jul 11, 2009 at 6:24 AM, milton ruser<milton.ruser at gmail.com>
wrote:
> my.values<-myfunction(1,10,100)
> min(my.values)
> max(my.values)
 That finds the minimum and maximum of a limited sample from a
univariate function. Extending this method to ten dimensions might be
a bit tricky...

If you want to find the min or max of a function to a higher
resolution or of higher dimensionality then you need an optimisation
algorithm.

 In R, see help(optim), help(optimise) and help(nlminb). Which one to
use will depend on your function and parameter constraints.

Barry