random:seed/3
用数字产生随机数种子
用法:
seed(A1, A2, A3) -> undefined | ran()
内部实现:
%% seed(A1, A2, A3) 
%%  Seed random number generation 
-spec seed(A1, A2, A3) -> 'undefined' | ran() when
      A1 :: integer(),
      A2 :: integer(),
      A3 :: integer().
seed(A1, A2, A3) ->
    seed_put({(abs(A1) rem (?PRIME1-1)) + 1,   % Avoid seed numbers that are
	      (abs(A2) rem (?PRIME2-1)) + 1,   % even divisors of the
	      (abs(A3) rem (?PRIME3-1)) + 1}). % corresponding primes.
-spec seed_put(ran()) -> 'undefined' | ran().
     
seed_put(Seed) ->
    put(random_seed, Seed).
用数字产生随机数种子
{MegaSecs, Secs, MicroSecs} = erlang:now(),
random:seed(MegaSecs, Secs, MicroSecs).