R help - Apr 2006 - help with vectorizing a function

Dear r-helpers,

I am developing a smoothing function that performs a casewise deletion of all 
the non-informative observations in a bivariate dataset following the Poisson - 
D'Avril algorythm.

But I am now facing two problems: 
1)Being based on loops, the function takes a lot of time before having done its 
work and even if I tried I was not able to vectorize it. 
2) I cannot control the degree of smoothing.

I have read the posting guide, the FAQ and have also RSiteSearched but without 
success. 

Can anybody help me?

Here is an example of the procedure:
(i have noticed also a different behaviour on different machines)
##################################

x <- rnorm(1000, sd=15)
y <- -x + rnorm(1000, sd=15)
 
plot(x, y,  ann=F, pch=16,   
      xlim=c(-50,50), ylim=c(-50, 50), asp=1,   col=2)

abline(lm(y ~ x))  
    
metamat<-c( 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0,
            1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0,
            0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0,
            1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0,
            0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0,
            1, 0, 0, 0)

matemot<-c( 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0,
            1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0,
            0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0,
            1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0,
            0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0,
            1, 0, 0, 0)


par(cex=.8, pch=15)
for(j in seq(-46, 60, 7)){
      for (i in -64:58){
  points(i+rep(1:8, 8), rep(1:8, each=8)-j, col=metamat)
  Sys.sleep(0.1)
  points(i+rep(1:8, 8), rep(1:8, each=8)-j, col="white")
  Sys.sleep(0.1)
  points(i+rep(1:8, 8)+1, rep(1:8, each=8)-j, col=matemot)
  Sys.sleep(0.1)
  points(i+rep(1:8, 8)+1, rep(1:8, each=8)-j, col="white")
                  }
                }
#################

Thank you, 
Glucinio