diff --git a/Data/extract_data.ml b/Data/extract_data.ml
new file mode 100644
index 0000000..0022d0f
--- /dev/null
+++ b/Data/extract_data.ml
@@ -0,0 +1,91 @@
+let read_file filename =
+  let ic = open_in filename in
+  let rec aux accu = 
+    try
+      let new_accu =
+        (input_line ic) :: accu
+      in
+      aux new_accu
+    with End_of_file -> 
+      (close_in ic; List.rev accu)
+  in
+  aux []
+
+
+let rec find_x x = function
+  | [] -> []
+  | line :: rest ->
+    let line = String.trim line in
+    match String.split_on_char ' ' line with
+    | x_test :: _ -> 
+      if x_test = x then line :: rest
+      else find_x x rest
+    | _ -> find_x x rest
+
+let get find_x conversion lines =
+  match find_x lines with
+  | line :: rest ->
+    begin
+      match String.split_on_char '=' line with
+      | _ :: n :: _ -> conversion @@ String.trim n, rest
+      | _ -> raise Exit
+    end
+  | [] -> raise Exit
+
+let read_float x = 
+  match String.split_on_char ' ' x with 
+  | x :: _ -> float_of_string x
+  | [] -> invalid_arg x
+
+
+let find_summary = find_x "N_det"
+let get_ndet = get find_summary int_of_string
+
+let find_nstates = find_x "N_states"
+let get_nstates = get find_nstates int_of_string
+
+let find_nsop = find_x "N_sop"
+let get_nsop = get find_nsop int_of_string
+
+let find_variance = find_x "Variance"
+let get_variance = get find_variance read_float
+
+let find_pt2 = find_x "PT2"
+let get_pt2  = get find_pt2 read_float
+
+let find_rpt2 = find_x "rPT2"
+let get_rpt2  = get find_rpt2 read_float
+
+let find_e   = find_x "E"
+let get_e    = get find_e   float_of_string
+
+
+let rec read_block lines =
+  let ndet, lines = get_ndet lines in
+  let nstates, lines = get_nstates lines in
+  let nsop, lines = get_nsop lines in
+  Printf.printf "%10d %10d" ndet nsop ;
+  let rec aux lines = function
+  | 0 -> (Printf.printf "\n%!" ; lines)
+  | n -> (
+    let e, lines = get_e lines in
+    let variance, lines = get_variance lines in
+    let pt2, lines = get_pt2 lines in
+    let rpt2, lines = get_rpt2 lines in
+    Printf.printf "  %16.10e  %16.10f  %16.10f" pt2 rpt2 e;
+    aux lines (n-1) )
+  in
+  aux lines nstates 
+
+let rec read_blocks lines =
+  try 
+    let lines = read_block lines in
+    read_blocks lines
+  with Exit -> ()
+
+let () =
+  Array.iteri (fun i fname -> 
+    if i = 0 then () else
+    let lines = read_file fname in
+    read_blocks lines) Sys.argv
+