+++ /dev/null
--module(life).
-
--export([bang/1]).
-
-
--define(CHAR_DEAD, 32). % " "
--define(CHAR_ALIVE, 111). % "o"
--define(CHAR_BAR, 45). % "-"
-
--define(GEN_INTERVAL, 100).
-
-
--record(state, {x :: non_neg_integer()
- ,y :: non_neg_integer()
- ,n :: pos_integer()
- ,bar :: nonempty_string()
- ,board :: array()
- ,gen_count :: pos_integer()
- ,gen_duration :: non_neg_integer()
- ,print_time :: non_neg_integer()
- }).
-
-
-%% ============================================================================
-%% API
-%% ============================================================================
-
-bang(Args) ->
- [X, Y] = [atom_to_integer(A) || A <- Args],
- {Time, Board} = timer:tc(fun() -> init_board(X, Y) end),
- State = #state{x = X
- ,y = Y
- ,n = X * Y
- ,bar = [?CHAR_BAR || _ <- lists:seq(1, X)]
- ,board = Board
- ,gen_count = 1 % Consider inital state to be generation 1
- ,gen_duration = Time
- ,print_time = 0 % There was no print time yet
- },
- life_loop(State).
-
-
-%% ============================================================================
-%% Internal
-%% ============================================================================
-
-life_loop(
- #state{x = X
- ,y = Y
- ,n = N
- ,bar = Bar
- ,board = Board
- ,gen_count = GenCount
- ,gen_duration = Time
- ,print_time = LastPrintTime
- }=State) ->
-
- {PrintTime, ok} = timer:tc(
- fun() ->
- do_print_screen(Board, Bar, X, Y, N, GenCount, Time, LastPrintTime)
- end
- ),
-
- {NewTime, NewBoard} = timer:tc(
- fun() ->
- next_generation(X, Y, Board)
- end
- ),
-
- NewState = State#state{board = NewBoard
- ,gen_count = GenCount + 1
- ,gen_duration = NewTime
- ,print_time = PrintTime
- },
-
- NewTimeMil = NewTime / 1000,
- NextGenDelay = at_least_zero(round(?GEN_INTERVAL - NewTimeMil)),
- timer:sleep(NextGenDelay),
-
- life_loop(NewState).
-
-
-at_least_zero(Integer) when Integer >= 0 -> Integer;
-at_least_zero(_) -> 0.
-
-
-do_print_screen(Board, Bar, X, Y, N, GenCount, Time, PrintTime) ->
- ok = do_print_status(Bar, X, Y, N, GenCount, Time, PrintTime),
- ok = do_print_board(Board).
-
-
-do_print_status(Bar, X, Y, N, GenCount, TimeMic, PrintTimeMic) ->
- TimeSec = TimeMic / 1000000,
- PrintTimeSec = PrintTimeMic / 1000000,
- ok = io:format("~s~n", [Bar]),
- ok = io:format(
- "X: ~b Y: ~b CELLS: ~b GENERATION: ~b DURATION: ~f PRINT TIME: ~f~n",
- [X, Y, N, GenCount, TimeSec, PrintTimeSec]
- ),
- ok = io:format("~s~n", [Bar]).
-
-
-do_print_board(Board) ->
- % It seems that just doing a fold should be faster than map + to_list
- % combo, but, after measuring several times, map + to_list has been
- % consistently (nearly twice) faster than either foldl or foldr.
- RowStrings = array:to_list(
- array:map(
- fun(_, Row) ->
- array:to_list(
- array:map(
- fun(_, State) ->
- state_to_char(State)
- end,
- Row
- )
- )
- end,
- Board
- )
- ),
-
- ok = lists:foreach(
- fun(RowString) ->
- ok = io:format("~s~n", [RowString])
- end,
- RowStrings
- ).
-
-
-state_to_char(0) -> ?CHAR_DEAD;
-state_to_char(1) -> ?CHAR_ALIVE.
-
-
-next_generation(W, H, Board) ->
- array:map(
- fun(Y, Row) ->
- array:map(
- fun(X, State) ->
- Neighbors = filter_offsides(H, W, neighbors(X, Y)),
- States = neighbor_states(Board, Neighbors),
- LiveNeighbors = lists:sum(States),
- new_state(State, LiveNeighbors)
- end,
- Row
- )
- end,
- Board
- ).
-
-
-new_state(1, LiveNeighbors) when LiveNeighbors < 2 -> 0;
-new_state(1, LiveNeighbors) when LiveNeighbors < 4 -> 1;
-new_state(1, LiveNeighbors) when LiveNeighbors > 3 -> 0;
-new_state(0, LiveNeighbors) when LiveNeighbors =:= 3 -> 1;
-new_state(State, _LiveNeighbors) -> State.
-
-
-neighbor_states(Board, Neighbors) ->
- [array:get(X, array:get(Y, Board)) || {X, Y} <- Neighbors].
-
-
-filter_offsides(H, W, Coordinates) ->
- [{X, Y} || {X, Y} <- Coordinates, is_onside(X, Y, H, W)].
-
-
-is_onside(X, Y, H, W) when (X >= 0) and (Y >= 0) and (X < W) and (Y < H) -> true;
-is_onside(_, _, _, _) -> false.
-
-
-neighbors(X, Y) ->
- [{X + OffX, Y + OffY} || {OffX, OffY} <- offsets()].
-
-
-offsets() ->
- [offset(D) || D <- directions()].
-
-
-offset('N') -> { 0, -1};
-offset('NE') -> { 1, -1};
-offset('E') -> { 1, 0};
-offset('SE') -> { 1, 1};
-offset('S') -> { 0, 1};
-offset('SW') -> {-1, 1};
-offset('W') -> {-1, 0};
-offset('NW') -> {-1, -1}.
-
-
-directions() ->
- ['N', 'NE', 'E', 'SE', 'S', 'SW', 'W', 'NW'].
-
-
-init_board(X, Y) ->
- array:map(fun(_, _) -> init_row(X) end, array:new(Y)).
-
-
-init_row(X) ->
- array:map(fun(_, _) -> init_cell_state() end, array:new(X)).
-
-
-init_cell_state() ->
- crypto:rand_uniform(0, 2).
-
-
-atom_to_integer(Atom) ->
- list_to_integer(atom_to_list(Atom)).
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