[R] Question regarding R plot

[Uwe Ligges]

 > optimize(function(x) -scores(x), interval=c(0.5, 0))
$minimum
[1] 0.1830174

$objective
[1] -11.67820


So the maximum is at x=0.183 with a score of 11.7, numerically.

Uwe Ligges



On 17.04.2010 16:30, Akito Y. Kawahara wrote:
> Hi, I am new to R, and have a quick question regarding an R script
> that I received from a kind colleague.
>
> I am trying to determine the "peak" (maximum value) of the graph that
> is plotted when executing the following. There is an input file called
> "rates_values.txt" which begins as:
>
> rateValue
> 0.375693
> 0
> 1.71274
> 0
> 0
> 1.02832
> 0
> 0.16343
> 1.02349
> 0
> 0
> 1.47258
> 0.703522
> 0.390541
> 1.83415
>
>
>
> The script, below, must run with the rates_values.txt in the same dir.
>
> #-------
> rates<-read.table("rates_values.txt",header=T)
> attach(rates)
> scores<-function(x){
>    l<-length(rateValue)
>    total<-0
>    for(i in 1:l){
>      value<-16*rateValue[i]*rateValue[i]*x*exp(-4*rateValue[i]*x)
>      total<-total+value
>    }
>    return(total)
> }
>
>
> #-------
> #preparing the plot
> linewidth=3
> linetype=3
> color="blue"
> xvalue=0.5
>
> plot(scores,xvalue,0,type="n",font.axis=2,xlim=c(xvalue,0))
> curve(scores,xvalue,add=TRUE,col=color,lty=linetype,lwd=linewidth,xlim=c(xvalue,0))
>
> #-------
>
> Can anyone help me figure out how to determine the peak (maximum
> "scores") value in the plot that is generated? It should be about 11.7
> but I would like to get an exact value. This should be a relatively
> easy question, but I'm new to R, and what I have tried doesn't seem to
> work.
>
> Thanks!
>
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