table.ml

open Extensions

(*
   the hashtable initially built up in run is a mapping
   from: time t
   to: number of vertices that received the message at time t

   and then it is made into a cumulative distribution
   i.e. maps to num vtcs that received at OR BEFORE time t

  then written out to output channel "chan"
*)


(*
  elapsed is the maximum time value in the table
  if there is no binding at vtx's time_received then set it to 1
  otherwise set it to its current value + 1.
*)
let add_to_table elapsed tbl vtx =
  let t = Node.time_received vtx in
  if (t > elapsed)
  then ()
  else
    if (Hashtbl.mem tbl t)
    then
      let prev = Hashtbl.find tbl t in
      Hashtbl.replace tbl t (prev + 1)
    else
      Hashtbl.add tbl t 1

let run chan g elapsed num_nodes =
  let dist_tbl = Hashtbl.create elapsed in
  for i = 0 to elapsed do Hashtbl.add dist_tbl i 0 done;
  (* build up distribution *)
  Network.G.iter_vertex (add_to_table elapsed dist_tbl) g;
  (* make it cumulative *)
  for i = 1 to elapsed do
    let prev = Hashtbl.find dist_tbl (i-1) in
    let curr = Hashtbl.find dist_tbl i in
    let cml = prev + curr in
    Hashtbl.replace dist_tbl i cml
  done;
  let dist_list = Hashtbl.to_list dist_tbl in
  let cmp (k1, v1) (k2, v2) = k1 - k2 in
  let dist_sorted = List.sort cmp dist_list in
  (* write out to channel *)
  List.iter (fun (k, v) -> Printf.fprintf chan "%d\t%d\n" k v) dist_sorted