Distributed Computing from https://www.cl.cam.ac.uk/projects/raspberrypi/tutorials/distributed-computing/

MergeClient.py

import socket 
import MergeSort 

HOST = '192.168.1.1' 
PORT = 50007 
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
s.connect((HOST, PORT)) 


#Receives arraystring in chunks 
arraystring = '' 
print 'Receiving data...' 
while 1:

data = s.recv(4096)	#Receives data in chunks 
#print data 
arraystring += data	#Adds data to array string 
if ']' in data:	#When end of data is received

break
array = eval(arraystring)	
print 'Data received, sorting array... ' 


#Sorts the array which it is allocated 
array = MergeSort.mergesort(array) 
print 'Array sorted, sending data...' 


#Converts array into string to be sent back to server 
arraystring = repr(array) 
s.sendall(arraystring)	#Sends array string 
print 'Data sent.' 

s.close()

MergeServer.py

import socket 

import MergeSort	#Imports mergesort functions 
import random 
import time 

#breaks down array into n sections where n is the number of processors 
def breakarray(array, n): 


sectionlength = len(array)/n	#length of each section 

result = [] 

for i in range(n):

if i < n - 1:
result.append( array[ i * sectionlength : (i+1) * sectionlength ] )
#include all remaining elements for the last section 
else:
result.append( array[ i * sectionlength : ] )

return result

#Create an array to be sorted 
arraylength = 100000	#Length of array to be sorted 
print 'Length of array is', arraylength 
array = range(arraylength)	#Creates array 
random.shuffle(array)	#Jumbles up array 


#Specify info on processors/computers 
procno = 2	#number of processors 
print 'Number of processors:', procno 
procID = 0	#ID of this processor(server) 
addr_list = []	#list of client addresses 


#Sets up network 
HOST = '' 
PORT = 50007 
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) 
s.bind((HOST, PORT)) 

s.listen(procno - 1)	#Listens for (n) number of client connections 
print 'Waiting for client...' 

for i in range(procno - 1):	#Connects to all clients

conn, addr = s.accept()	#Accepts connection from client 
print 'Connected by', addr 
addr_list.append(addr)	#Adds address to address list



#Start and time distributed computing sorting process	
start_time = time.time()	#Records start time 

sections = breakarray(array, procno)	#splits array into sections for every client 

for i in range(procno - 1):	#Converts array section into string to be sent

arraystring = repr(sections[i+1]) 
conn.sendto( arraystring , addr_list[i] )	#Sends array string 
print 'Data sent, sorting array...'

array = MergeSort.mergesort(sections[procID])	#Sorts section and stores it in array 
print 'Array sorted.' 

for i in range(procno - 1):	#Receives sorted sections from each client

arraystring = '' 
print 'Receiving data from clients...' 
while 1:
data = conn.recv(4096)	#Receives data in chunks 
arraystring += data	#Adds data to array string 
if ']' in data:	#When end of data is received

break
print 'Data received, merging arrays...'	
array = MergeSort.merge(array, eval(arraystring))	#Merges current array with section from client	
print 'Arrays merged.'

conn.close() 
time_taken = time.time() - start_time	#Calculates and records time_taken 

print 'Time taken to sort is ', time_taken, 'seconds.'