From c04c583261cf324ffd6a131a32e1b2c41668600a Mon Sep 17 00:00:00 2001
From: Siraaj Khandkar <siraaj@khandkar.net>
Date: Tue, 31 Jul 2012 16:21:13 -0400
Subject: [PATCH] Logging and printing compute time for each generation.

---
 001/src/life_observer.erl | 20 ++++++++++++++------
 001/src/life_time.erl     | 12 +++++++++---
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/001/src/life_observer.erl b/001/src/life_observer.erl
index e16fcf7..f2d6baa 100644
--- a/001/src/life_observer.erl
+++ b/001/src/life_observer.erl
@@ -7,7 +7,7 @@
         ,register_with_logger/0
         ,add_handler/2
         ,delete_handler/0
-        ,log_generation/3
+        ,log_generation/4
         ]).
 
 %% Callbacks
@@ -55,8 +55,8 @@ delete_handler() ->
     gen_event:delete_handler(?EVENT_MGR_REF, ?HANDLER, Args).
 
 
-log_generation(GenID, Dead, Alive) ->
-    Event = {generation, GenID, Dead, Alive},
+log_generation(GenID, GenDuration, Dead, Alive) ->
+    Event = {generation, GenID, GenDuration, Dead, Alive},
     gen_event:notify(?EVENT_MGR_REF, Event).
 
 
@@ -88,7 +88,7 @@ init([X, Y]) ->
     ok = validate_makedir(file:make_dir(?PATH_DIR__DATA)),
     {ok, LogFile} = file:open(FilePath, write),
 
-    CSVHeaders = ["Generation", "Dead", "Alive"],
+    CSVHeaders = ["Generation", "Duration", "Dead", "Alive"],
     ok = do_write(LogFile, list_to_csvline(CSVHeaders)),
 
     {ok, #state{log_file=LogFile}}.
@@ -99,10 +99,14 @@ terminate(_Reason, #state{log_file=LogFile}=State) ->
     {ok, State}.
 
 
-handle_event({generation, GenID, Dead, Alive},
+handle_event({generation, GenID, GenDuration, Dead, Alive},
     #state{log_file=LogFile}=State) ->
 
-    Values = [integer_to_list(I) || I <- [GenID, Dead, Alive]],
+    Values = [integer_to_list(GenID)
+             ,float_to_string(GenDuration)
+             ,integer_to_list(Dead)
+             ,integer_to_list(Alive)
+             ],
     ok = do_write(LogFile, list_to_csvline(Values)),
     {ok, State}.
 
@@ -122,3 +126,7 @@ do_write(File, Line) ->
 
 list_to_csvline(List) ->
     string:join(List, ?CSV_DELIMITER).
+
+
+float_to_string(Float) ->
+    io_lib:format("~f", [Float]).
diff --git a/001/src/life_time.erl b/001/src/life_time.erl
index 1140c79..143573d 100644
--- a/001/src/life_time.erl
+++ b/001/src/life_time.erl
@@ -33,6 +33,7 @@
                ,state_pairs     :: list(tuple(integer(), integer())) | []
                ,replies_pending :: integer()
                ,gen_id          :: integer()
+               ,gen_began       :: erlang:timestamp()
                }).
 
 
@@ -84,10 +85,12 @@ handle_info(next_gen,
           ,gen_id=GenID
           }=State) ->
 
+    GenBegan = os:timestamp(),
     NewGenID = GenID + 1,
     ok = life_lib:cast_one2all(Cells, {next_gen, NewGenID}),
     NewState = State#state{replies_pending=NumCells
                           ,gen_id=NewGenID
+                          ,gen_began=GenBegan
                           ,num_dead=0
                           ,num_alive=0
                           },
@@ -105,6 +108,7 @@ handle_cast({report_state, {CellID, GenID, CellState}},
           ,state_pairs=StatePairs
           ,replies_pending=RepliesPending
           ,gen_id=GenID
+          ,gen_began=GenBegan
           ,num_cells=NumCells
           }=State) ->
 
@@ -124,11 +128,13 @@ handle_cast({report_state, {CellID, GenID, CellState}},
             ),
             StateChars = [state_to_char(S) || {_, S} <- SortedStatePairs],
 
-            ok = life_observer:log_generation(GenID, NewNDead, NewNAlive),
+            GenDuration = timer:now_diff(os:timestamp(), GenBegan) / 1000000,
+
+            ok = life_observer:log_generation(GenID, GenDuration, NewNDead, NewNAlive),
 
             ok = io:format(
-                "X: ~b Y: ~b CELLS: ~b DEAD: ~b ALIVE: ~b GENERATION: ~b~n",
-                [X, Y, NumCells, NewNDead, NewNAlive, GenID]
+                "X: ~b Y: ~b CELLS: ~b DEAD: ~b ALIVE: ~b GENERATION: ~b DURATION: ~f~n",
+                [X, Y, NumCells, NewNDead, NewNAlive, GenID, GenDuration]
             ),
             ok = do_print_bar(X),
             ok = do_print_state_chars(X, StateChars),
-- 
2.20.1