From: Fredrik <fredjoha@...>
Date: 2008-04-18T15:45:05+09:00
Subject: Re: Parallel for loop

> It's different with blocks:

(reposting, my last post didn't appear(?))
Great, thanks for that lesson! It would look like this then.

  def forkmap(n = nil)
    nproc = 0
    result = map do |*a|
      r, w = IO.pipe
      fork do
        r.close
        w.write( Marshal.dump( yield(*a) ) )
      end
      if n and (nproc+=1) >= n
        Process.wait ; nproc -= 1
      end
      [ w.close, r ].last
    end
    Process.waitall
    result.map{|r| Marshal.load [ r.read, r.close ].first}
  end