#! /usr/bin/env python
# -*- mode:python; coding:utf-8; -*-

#  Calculation of Pi using quadrature.  Use the Parallel Python package.  Parallel Python appears not to be
#  packaged for use with Python 3 in the Ubuntu package repository.
#
#  Copyright © 2008–2011 Russel Winder

import time

import sys
import os
import pp

def processSlice ( id , sliceSize , delta ) :
    sum = 0.0
    for i in xrange ( 1 + id * sliceSize , ( id + 1 ) * sliceSize + 1 ) :
        x = ( i - 0.5 ) * delta
        sum += 1.0 / ( 1.0 + x * x )
    return sum

def execute ( processCount ) :
    n = 10000000 # 100 times fewer due to speed issues.
    delta = 1.0 / n
    startTime = time.time ( )
    sliceSize = n / processCount
    server = pp.Server ( secret = 'blahblahblah' )
    jobs = [ server.submit ( processSlice , ( i , sliceSize , delta ) ) for i in xrange ( 0, processCount ) ]
    pi = 4.0 * delta * sum ( [ job ( ) for job in jobs ] )
    elapseTime = time.time ( ) - startTime
    print ( "==== Python PP pi = " + str ( pi ) )
    print ( "==== Python PP iteration count = " + str ( n ) )
    print ( "==== Python PP elapse = " + str ( elapseTime ) )
    print ( "==== Python PP process count = " + str ( processCount ) )
    print ( "==== Python PP processor count = " + str ( server.get_ncpus ( ) ) )
    server.print_stats ( )
    
if __name__ == '__main__' :
    execute ( 1 )
    print
    execute ( 2 )
    print
    execute ( 8 )
    print
    execute ( 32 )