'''
Created on 23/04/2012

@author: Davidmh
'''
from __future__ import division
from multiprocessing import Queue, Process, Pool
import time
import random

pars=[1,2]
ncpu=2


def calculate(par):
    time.sleep(0.5*random.random()+0.5)
    res=2*par
    print par,',',res
    q.put([par,res])
    print '---'



def saving(q, savefile):
    print '==Saving=='
    while True:
        try:
            item=q.get(False)
            print item
        except :
            print '%'
            time.sleep(0.5)
            continue

        savefile.write(item[0])
        savefile.write(',')
        savefile.write(item[1])
        savefile.write('\r\n')



if __name__=="__main__":
    print 'Started!'

    q=Queue()

    with open('test_par.txt', 'w', buffering=0) as savefile:
        savefile.write('This is the test file\r\n')
        print 'Standard map:'
        map(calculate, pars)
        print

        print 'Parallel map'
        pool = Pool(processes=min(ncpu, len(pars)))
        pool.map_async(calculate, pars, chunksize=1)
        pool.close()

        k=Process(target=saving, args=(q,savefile,))
        k.start()
        pool.join()
        print q.qsize()
        q.close()
        q.join_thread()

        k.terminate()
        pool.terminate()
    print 'End!'