[R] help with integration

[andrea.toreti at apat.it]

Dear all,
I have a problem with the integration of the following function.
Could you please give some suggestions?

Thank you very much!!!

y<-rnorm(n=100)

f<-function(x,xi,h){
  n<-length(xi)
  Ke<-c()
  for(t in 1:n) {
   Ke[t]<-dnorm((x-xi[t])/h)
  }
  fke<-sum(Ke)*(1/(n*h))
  fke<-fke^2
  return(fke)
}
integrate(f,-Inf,Inf,xi=y,h=0.32)

I obtained this error:
   evaluation of function gave a result of wrong length
In addition: There were 50 or more warnings (use warnings() to see the  
first 50)
50: In Ke[t] <- dnorm((x - xi[t])/h) :
   number of items to replace is not a multiple of replacement length