]> > my program need to calculate a hash key of a matrix (with dimension 8 > x 8). It is necessary that this calculation is very fast, so my > program will update the hash key after every small modification of the > matrix. My problem is that the hash key should be an unsigned int > or an unsigned long in. > > My problem occurs here (Mersenne prime number 2^31-1): > let big_prim = 2147483647 > val big_prim : int = -1 OCaml does not of unsigned integers. Using Int64 or Bignum modules as Sven suggested you would be a threat to your program performances since it involves boxing. BTW, why do care about the integer sign ? Only the printer show you -1, but the hardware representation, taking note that OCaml int are 31 bits, doesn't change between signed and unsigned, does it ? The only main difference I see is when comparing two signed integers. Then perhaps something like : let ui_compare x y = x lsr 16 < y lsr 16 || x land 0xFFFF < y land 0xFFFF Is what you need. ui_compare 1 2;; // true ui_compare (-1) 2;; // false Nicolas Cannasse ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners