[R] mode

(Ted Harding) Ted.Harding at nessie.mcc.ac.uk
Sat Dec 13 14:19:43 CET 2003


Sorry, typo:

On 13-Dec-03 Ted Harding wrote:
> Example of kernel density estimation:
> 
>   X<-c(rnorm(200),2+0.5*rnorm(300))
>   hist(X,freq=FALSE,breaks=(-4)+0.2*(0:50))
>   S<-density(X,from=(-4),to=5,bw=0.2)
>   N<-length(S$y)
>   V1<-S$y[1:(N-2)];V2<-S$y[2:(N-1)];V3<-S$y[3:N]
>   ix<-1+which((V1<V2)&(V2>V3))
>   lines(S$x,S$y,col="red")
>   points(S$x[ix],S$y[ix],col="blue")
> 
> where the index ix identifies all the local modes of the fitted
> spline density estimate S. These include the global mode[s]
> 
>   S$x[which(S$y==maxS$y)]

  S$x[which(S$y==max(S$y))]

Ted.


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Date: 13-Dec-03                                       Time: 13:19:43
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