I'm going through the problems on projecteuler.net to learn how to program in Erlang, and I am having the hardest time creating a prime generator that can create all of the primes below 2 million, in less than a minute. Using the sequential style, I have already written three types of generators, including the Sieve of Eratosthenes, and none of them perform well enough.

I figured a concurrent Sieve would work great, but I'm getting bad_arity messages, and I'm not sure why. Any suggestions on why I have the problem, or how to code it properly?

Here's my code, the commented out sections are where I tried to make things concurrent:

-module(primeserver). -compile(export_all). start() -> register(primes, spawn(fun() -> loop() end)). is_prime(N) -> rpc({is_prime,N}). rpc(Request) -> primes ! {self(), Request}, receive {primes, Response} -> Response end. loop() -> receive {From, {is_prime, N}} -> if N From ! {primes, false}; N =:= 2 -> From ! {primes, true}; N rem 2 =:= 0 -> From ! {primes, false}; true -> Values = is_not_prime(N), Val = not(lists:member(true, Values)), From ! {primes, Val} end, loop() end. for(N,N,_,F) -> [F(N)]; for(I,N,S,F) when I + S [F(I)|for(I+S, N, S, F)]; for(I,N,S,F) when I + S =:= N -> [F(I)|for(I+S, N, S, F)]; for(I,N,S,F) when I + S > N -> [F(I)]. get_list(I, Limit) -> if I [I*A || A [] end. is_not_prime(N) -> for(3, N, 2, fun(I) -> List = get_list(I,trunc(N/I)), lists:member(N,lists:flatten(List)) end ). %%L = for(1,N, fun() -> spawn(fun(I) -> wait(I,N) end) end), %%SeedList = [A || A %% lists:foreach(fun(X) -> %% Pid ! {in_list, X} %% end, SeedList) %% end, L). %%wait(I,N) -> %% List = [I*A || A lists:member(X,List) %% end.