The following command crashes my Mac OS X version of R: (I'm running R on a PowerMac G5, with 1 GB of RAM and dual processors.) > arima.0 <- arima(w3.ts,order=c(1,0,0),seasonal=list(order=c (1,0,0),period=365)) -David Here is some background: w3.ts is hourly temperature data with about 20% NA's. It contains about 3.5 years of data. I am using period = 365, which makes sense me to me. Is this wrong? > summary(w3.ts) Min. 1st Qu. Median Mean 3rd Qu. Max. NA's 14.00 54.00 68.00 66.09 78.00 108.00 2976.00 > length(w3.ts) [1] 29542 > frequency(w3.ts) [1] 24 > deltat(w3.ts) [1] 0.04166667 > w3.ts[300:400] [1] 61 63 64 68 66 64 61 59 62 56 53 49 43 45 47 46 44 42 42 40 42 48 52 55 [25] 57 59 60 60 60 59 52 50 49 45 47 41 38 36 37 35 36 37 39 39 38 42 49 54 [49] 58 61 63 64 63 62 59 55 54 51 55 53 53 NA NA NA NA NA NA NA NA NA NA NA [73] NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA [97] NA NA NA NA NA > w3.ts[720:770] [1] NA NA NA NA NA NA NA NA [9] NA NA NA NA NA NA NA NA [17] NA NA NA NA NA NA NA NA [25] NA 41.50000 46.50000 40.00000 42.50000 37.50000 41.00000 36.50000 [33] 40.50000 38.50000 42.50000 41.00000 46.00000 43.50000 46.50000 43.50000 [41] 47.50000 41.50000 47.50000 42.50000 47.33333 47.66667 51.00000 41.50000 [49] 51.50000 40.00000 52.50000 -David