セルオートマトン法・ω・

cellular_automata.erl

-module(cellular_automata).
-compile(export_all).

make_rule(N) ->
   <<B1:1, B2:1, B3:1, B4:1, B5:1, B6:1, B7:1, B8:1>> = <<N>>,
   fun({X1, X2, X3}) ->
      <<Idx>> = <<0:5, X1:1, X2:1, X3:1>>,
      lists:nth(Idx+1, [B8,B7,B6,B5,B4,B3,B2,B1])
   end.

make_field(Density, Length) ->
   lists:map(fun(_) ->
      case random:uniform() =< Density of
         true  -> 1;
         false -> 0
      end
   end, lists:seq(1, Length)).

get_part(Field, N) when N =:= length(Field) ->
   {lists:nth(N-1, Field), lists:nth(N, Field),   lists:nth(1, Field)};
get_part(Field, N) when N =:= 1 ->
   {lists:last(Field),     lists:nth(N, Field), lists:nth(N+1, Field)};
get_part(Field, N) ->
   {lists:nth(N-1, Field), lists:nth(N, Field), lists:nth(N+1, Field)}.

apply_nth(Field, Rule, N) ->
   io:format("~p~n", [Field]),
   lists:foldl(fun(_, OldField) ->
      NewField = lists:map(fun(I) -> Rule(get_part(OldField, I)) end, lists:seq(1, length(Field))),
      io:format("~p~n", [NewField]),
      NewField
   end, Field, lists:seq(1, N)),
   ok.