Love that analogy. http://www.c2.com/cgi/wiki?DogFood As an aside, back in the day I stopped trying to learn Autodif when Dave himself started using ADMB, a true testament to an early dogfood eater. Cheers, Jim James Ianelli REFM Division, Alaska Fisheries Science Center, NOAA 7600 Sand Point Way NE Seattle WA 98115 Ph. 206 526 6510