问题暂已解决

x<-ts(x[,2],start=1950)
y<-c(1:16)
i=1
for(p in 0:3){
  for(q in 0:3){
    m<-arima(x,order=c(p,0,q),method = "ML")
    y[i]<-m$aic
    print(y)
    i=i+1
  }
}
y<-matrix(y,4,4)
min(y)
which(y== min(y), arr.ind = TRUE)

....
out <- matrix(NA, nrow = p, ncol = q)
....
out[p, q] <- m$aic
.....

多谢！