Pwrake - Parallel and Distributed Ruby
                   Masahiro Tanaka 2012-02-14

* Tested for

 - ruby 1.9.2p0

* Install

 $ ruby setup.rb

* How to use

 - create `rhosts' file : list of remote hosts

    $ cat rhosts
    host1
    host2
    host3
    ..

 - enable ssh-login to rhosts w/o passwd

 - demo program

    $ cat test/t.rb
    comm = Communicator.instance
    rank = comm.rank
    size = comm.size
    data = [rank,`hostname`.chomp]
    comm.send((rank+1)%size,0,data)
    p [:send, data, :recv, comm.recv((rank-1)%size,0)]

 - run

    $ pdrb test/t.rb

* Class method

 - Communicator.instance #=> communicator

* Instance methods

 - Communicator#rank
 - Communicator#size
 - Communicator#send(rank,tag,obj)
 - Communicator#recv(rank,tag) #=> obj