/* * $Id: CDAgent_ag2672.java,v 1.3 2008/07/08 03:36:51 nemo Exp $ * * Copyright (c) 2008, Nemo Semret. * * Your agent must implement this interface. All the constants of the * game are set here as well. Do not hardcode the constants in your * agent. You should refer to them as these static variables. Some of * these values may change in the final run so you must design your * algorithm for the general case. */ package edu.columbia.ee.e6773; /** * Interface for player agent representing Information Provider in Content Delivery Game. * http://www.ee.columbia.edu/~nemo/teaching/Content_Delivery_Game.html * @author Nemo Semret */ public class CDAgent_ag2672 implements CDNAgent { /******************* Variables I have included ********************************/ /* bk is the array that holds the number of users that uses network bandwidth*/ public long[] bk; /* ck is the array that holds the number of users that uses the cache*/ public long[] ck; /* day_counter is used to indicate the current day */ public int day_counter = 0; /* ak is the array of boolens that will be returns tellling us which networks will need cache */ public boolean[] ak; /* avg_N is an array that contains the avg N for every network for a given day*/ public double[] avg_N; // FIXME: unnecessary array you are just updating day_N locally anyway /* day_N is the array that contains the N value for evey day */ public double[] day_N; /* expected congestion is the array the save 0 if no congestion or the loss due to congestion*/ public double[] expected_cong; public CDAgent_ag2672 () { bk = new long[K]; ck = new long[K]; ak = new boolean [K]; avg_N = new double [K]; day_N = new double [1000]; expected_cong = new double[K]; for (int k = 0; k < K; k++) { ak[k] = true; } } /** Coded By Abdulhamid Ghandour * UNI: ag2672 * Submitted May-19-2008 * The function startDay will take the input X in Gbytes. In the beginning * i will estimate N for evey Network and find an average for the day. * Then i will Find the N for that day by averaging the estimated N over * all previous day and will use that N later on. Then using the values of * C (capacity) and bk, i can predict if there is congestion in a network * or not, and that will help me in some cases. No i check, If i * previously cached on a network and the netork gave me positive revenue, * then i stay cache it, else i will stop caching. On the other had If i * didnt previously cache, but i know that someone is caching, i check if * sharing the users using cache by adding a cache will give positive * revenue, then I will cache, else i will not add a cache. Also is no one * is caching, including me, then if my revenue is a bit better than the * congestion loos, i will cache, else i won't cache. */ public boolean[] startDay(long X) { // FIXED: always cache first round or else N remains zero throughout and never cache if (day_counter == 0) { for(int j = 0; j < K; j++) { ak[j] = true; } day_counter++; return ak; } int N_counter =0; int avg_users= 10000; double N_total = 0; double N = 0 ; double current_N_tot = 0; double CACHE_COST = (Sc + Pc * X/1073741824.0); // FIXED /*try to find N from every network that we had used a cache in it using the value bk*/ for(int j = 0; j < K; j++) { if ( ak[j] == true && bk[j]>0){ /*if we cached in that network, then our bk is on avergve 1/N *( 1-q) *avg_user */ avg_N[j]= (avg_users * (1-q))/bk[j]; /* we add these N we estimated for every network for that day */ N_total = N_total + avg_N[j]; N_counter++; } else avg_N[j]=0; } /*this will calculate the Avg N for that day and will store it in day_N array */ if (N_counter>0) { //FIXED day_N[day_counter] = (N_total / N_counter); } else { day_N[day_counter] = day_N[day_counter - 1]; } /*Encrement the day counter*/ day_counter++; /*this will add the N values for all previous day */ for(int r = 0; r < day_counter; r++) current_N_tot = current_N_tot + day_N[r]; /*and this N will be the average over all days and round it */ N = Math.round(current_N_tot / day_counter); for (int t = 0; t < K; t++){ expected_cong[t] = 0; /* if the capacity c is small, then congestion happens and we lose * some resources the expected_cong arry will have zero if no * congestion is predicted or it will have *a negative value * crosponding to the loss of mony on bandwidth */ if (C[t]*60*60*24*1000000 < X*8*bk[t]*N) // FIXED Gbyte -> byte expected_cong[t] = -Pb*bk[t]*X/1073741824.0; } for(int i = 0; i < K; i++){ /*if the previuos day, i have chached this network then */ if ( ak[i] == true ){ /* this is if caching gave me positive revenue then keeep caching else,stop caching*/ if ( (ck[i] * V) > CACHE_COST) ak[i] = true; else ak[i] = false; } /*the other case, if previously i didnt cache, then i can cache if i can make revenue doing so */ else{ /* this is if i am getting a low value which means someone is caching then i check if cache will make me better of, then i will cache*/ if ( bk[i] < (avg_users * (1-q) /(N*2) )){ // FIXED: 2 is in denominator /*estimate my ck[i] as 10000 /(1+N/3) assuming that N/3 *will be caching if using this estimation we can see that *caching will give us positive revenue then we cache*/ if ( (avg_users * q * V/(1+N/3)) > CACHE_COST ) ak[i] = true; else ak[i] = false; } else{ /*this mean that my bk[i] is high which implies that no one is caching, thus i should cache if it gives positive revenue taking into acount congestion*/ if (avg_users * q * V > CACHE_COST + expected_cong[i]) ak[i] = true; else ak[i] = false; } } } return ak; } public void endDay(long[] b, long[] c) { /* at the end og the day, the arrays contains the number of users for each network will be given and saved to arrays bk and ck*/ bk = b; ck = c; } }