let mult a b =
let m = Array.length a in
let n = Array.length b.(0) in
let p = Array.length a.(0) in
let c = Array.make_matrix m n 0. in
for i = 0 to m - 1 do
for j = 0 to n - 1 do
for k = 0 to p - 1 do
c.(i).(j) <- c.(i).(j) +. a.(i).(k) *. b.(k).(j)
done
done
done ;
c