cmcbride

(* compute GCD. playing with OCaml *)

let rec gcd n m = 
    if m = 0 then 
        n 
    else 
        if n > m 
        then 
            gcd (n-m) m
        else 

cmcbride

(* for use with Array.  Easy way to create an index, and then sort the index *)

let index a = Array.init ( Array.length a) (fun i -> i) 

let sort_index a idx = 
        let cmpi i j = compare a.(i) a.(j) in 
        Array.fast_sort cmpi idx