Question

i was trying to store my simulation output inside an array. I have written the following code:

nsim=50
res=array(0,c(nsim,20,20))
for(i in 1:nsim) {
    cat("simul=",i,"\n")
    simulated = NULL
    stik.simulated = NULL
    simulated = rpp(....)
    stik.simulated = STIKhat(....)
    # from stik.simulated we will get $khat and $Ktheo and 
    # the dimension of stik.simulated$Khat-stik.simulated$Ktheo is 20 x 20
    res[i,,] = stik.simulated$Khat - stik.simulated$Ktheo  
}

But whenever the function is trying to store the output inside an array, I get the following error:

simul= 1 
Xrange is  20 40 
Yrange is  -20 20 
Doing quartic kernel
Error in res[, , i] = stik.simulated$Khat - stik.simulated$Ktheo : 
  subscript out of bounds

seeking your help. Thanks.

Answer 1

I think you need to organize your code to avoid such errors. I assume you are using package stpp.

First You create, a function which generate the matrix of each iteration; Try to test your function with many values.

stick_diff <- function(u,v){
  u <- seq(0,u,by=1)
  v <- seq(0,v,by=1)
  simulated <- rpp(...)                    ## call here rpp with right parameters
  stik <- STIKhat(xyt=simulated$xyt,
                     dist=u, times=v, ...)
  stik$Khat-stik$Ktheo                     ## !! here if u#v you will have recycling!
}

Once you are sure of your function you call it the loop, with right dimensions.

nsim <- 50
u    <- 20
res=array(0,c(nsim,u,u))
for(i in 1:nsim)
  res[i,,] <- stick_diff(i,u,u)