Question

Solve the following three problems using "Java with Akka Actors". Read the submission instructions carefully.

Problem 1 (25 Points): Fibonacci Numbers 1. Develop an actor program for computing Fibonacci numbers concurrently. Particularly, create an actor which receives a request for a particular Fibonacci number from a client actor. If it is one of the base cases, the actor replies with a message containing the answer; otherwise, it creates the two sub-problems you would normally create in a recursive implementation. It then creates two new (Fibonacci) actors, and sends one subproblem to each. Once it has received replies from these actors, it adds them to produce its result, and sends it back to the computation's client.

Answer 1

Actor:

public class Actor extends Thread
{
//number will be the input whose fibonacci we need to create
private int number;
//Result will store the final answer
public int result;

public Actor(int number)
{
this.number = number;
}

public int getResult()
{
return this.result;
}
public void run()
{
//Base case is if number is 2 or lesst than 2 it sets result to 1
//fibonacci series is 0 1 1 2 3
//so second fibonaci is 1
if (number <= 2)
result = 1;
else
{
//Since we are going to use threads we need to use exceptions
try
{
//Create the first actor and assign him one of the number to calculate
Actor first = new Actor(number - 1);
//Create the first second and assign him one of the number to calculate
Actor second = new Actor(number - 2);
//calls the instance of first actor
first.start();
//call the instance of second actor
second.start();

first.join();

second.join();
//result would be the sum of answers given by both acotrs
result = first.result + second.result;
}
catch (InterruptedException ex)
{
System.out.println("Exception occured");
}
}
}
}

Client class:

import java.util.*;

public class Main {
public static void main(String[] args) throws Exception
{
try
{
//Scanner for taking the input
Scanner sc = new Scanner(System.in);
//Taking input from the user
int number = sc.nextInt();
//CAlling the actor class with the input
Actor fibonaci = new Actor(number);
//Starting the main thread
fibonaci.start();
//join all the threads to get the answer
fibonaci.join();
//printing the answer
System.out.println(fibonaci.getResult());
}
catch(Exception e)
{
System.out.println("Exception occured");
}
}
}

Input/Output

input - 8

output - 21

fibonacci series - 1 1 2 3 5 8 13 21