Distributed Genetic Algorithms

Prof: Paul Schragger

Abdo Achkar

Fall 2005

Villanova University

Problem Definition

Distributed genetic algorithms to simulate the evolution of an animal.

General use case: Approximation problems that have no algorithmic

solution We might want to use [distributed] genetic

algorithms if The problem needs a lot of computation We want to avoid local minima/maxima

Genetic Algorithms

Program that optimizes a set of bit Strings that we name “Chromosome” according to a function that we call “fitness function”.

The bit Strings will Reproduce Be mutilated Be selected: the fittest will remain for the following

generation

Object Oriented Design

NetNodeHas-a

Population

Chromosome

ChromosomeLeg

Has-a

Has-a

Has-aIpList

Has-a

DatagramListener

Has-a

DatagramBroadcaster

Extends Thread

DgramListenerWorker

Has-a

Extends Thread

PacketHandler

Has-a

The Work Flow

BroadCast Anybody here

Wait for reply(DgramListener)

and

Solve Instance

Start

PacketHandlerReceived Packets

Associated event with the packet

Note: this event can be a broadcast or a new listen

DgramListenerWorker

MsgParser

Inside the DgramPacketHandler

private void doCommand(int command,DatagramPacket p) { switch(command) { case MsgClass.WAIT_FOR_DATA:

… case MsgClass.MSG_ANYBODY_HERE:

… case MsgClass.MSG_SERVER_CONNECT_TIMEOUT:

… case MsgClass.MSG_SERVER_IS_DOWN:

… case MsgClass.MSG_YOU_ARE_THE_SERVER:

…}

}

The Voting Algorithm

Wait for Server’s Data

event

Client detects server’s time out

Broadcasts the server failed Listen for votes

Vote Received

Add to IP list

Msg:vote

Vote Wait for votesresult

1

2

3 3

4

5

5

End of Vote

Send “you are the server” To the highest IP

6

7

Act Accordingly

8

The Program FlowAnybody here

Listen

Data Received

Timeout

We are Clients

ListenData Received

Timeout

Broadcast: vote

Update Population

Vote call received

Listen

Vote

We are servers

Msg:You are the server

BroadcastWe are server

Listen

Add IP to list

Vote Received

Timeout

Tell the server

We Serve

Listen

Anybody here

Send Data

Vote call received

Data Received

References Artificial Intelligence, Negnevitsky. Distributed Computing, Attiya and Welch Distributed Application Programming in C++,

Maddox The Essential Guide to Networking, Keogh Network Management, Subramanian Java How to Program, Deitel and Deitel Distributed Systems, Tanenbaum and Van Steen C++ In Action, Melweski Inertie d’un système, M Devel, Université de

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