Project 1:- Project is created in scala using akka actors. Problem statement :- Find the sequence of natural numbers so that after adding up the squares of these numbers we get a single number whose square is equal to the previous sum
Project 2:- s described in class Gossip type algorithms can be used both for group commu- nication and for aggregate computation. The goal of this project is to determine the convergence of such algorithms through a simulator based on actors written in Scala. Since actors in Scala are fully asynchronous, the particular type of Gossip implemented is the so called Asynchronous Gossip. Gossip Algorithm for information propagation The Gossip algorithm involves the following: • Starting: A participant(actor) it told/sent a roumor(fact) by the main process • Step: Each actor selects a random neighboor and tells it the roumor • Termination: Each actor keeps track of rumors and how many times it has heard the rumor. It stops transmitting once it has heard the roumor 10 times (10 is arbitrary, you can play with other numbers).
Push-Sum algorithm for sum computation • State: Each actor Ai maintains two quantities: s and w. Initially, s = xi = i (that is actor number i has value i, play with other distribution if you so desire) and w = 1 • Starting: Ask one of the actors to start from the main process. • Receive: Messages sent and received are pairs of the form (s,w). Upon receive, an actor should add received pair to its own corresponding val- ues. Upon receive, each actor selects a random neighboor and sends it a message. • Send: When sending a message to another actor, half of s and w is kept by the sending actor and half is placed in the message. • Sum estimate: At any given moment of time, the sum estimate is s w where s and w are the current values of an actor. • Termination: If an actors ratio s w did not change more than 10−10 in 3 consecutive rounds the actor terminates. WARNING: the values s and w independently never converge, only the ratio does. Topologies The actual network topology plays a critical role in the dissemi- nation speed of Gossip protocols. As part of this project you have to experiment with various topologies. The topology determines who is considered a neighboor in the above algorithms. • Full Network Every actor is a neighboor of all other actors. That is, every actor can talk directly to any other actor. • 2D Grid: Actors form a 2D grid. The actors can only talk to the grid neigboors. • Line: Actors are arranged in a line. Each actor has only 2 neighboors (one left and one right, unless you are the first or last actor). • Imperfect 2D Grid: Grid arrangement but one random other neighboor is selected from the list of all actors (4+1 neighboors).