Dear group,

I have an question about data structure and types. I have a function calculates transitive closure of relation represented as an adjacency matrix

let trans_closure (m: 'a array array) : 'a array array =

  let last_cols = length m - 1 in

    for k = 0 to last_cols do

      for i = 0 to last_cols do

for j = 0 to last_cols do

 m.(i).(j) <- m.(i).(j) || (m.(i).(k) && m.(k).(j))

done;

      done;

  done;

  m

;;

(* transpose matrix A is the matrix A' formed by turning rows into

   columns and vice versa: (A')i,j = Aj,i.*)

let transpose (m: 'a array array) : 'a array array =

  let tc = trans_closure m in

  let last_cols = length m - 1 in

  for i = 0 to last_cols do

    for j = 0 to last_cols do

      tc.(j).(i) <- tc.(i).(j)

    done;

  done;

  tc

;;

I would like to compute equivalence classes, it is disjoint between matrix transitive closure  and matrix transpose. I would like it returns for me a new list with the type: list of list [[]]

I have a function convert 'a array array to 'a list list

let to_list (m : 'a array array) : 'a list list =

  List.map to_list (to_list m)

let eq_class (m: 'a array array) : 'a list list =

  let lst = length m - 1 in

      for i = 0 to lst do

for j = 0 to lst do

 let a = tc.(i).(j) && trans.(i).(j) in

            if a

            then 

           ???

I'm stuck here, I don't know how I can add the result "a" into the new list of list. I think I should create a new list with type 'a list list, but I don't know where I should write it?

Thank you for helping me understand and give me some advises.

Best regards,

Gwen