From a243be6b0e0af216b0bd53bc82d6cd315d43b181 Mon Sep 17 00:00:00 2001
From: Aberrahmane Sider <ar.sider@univ-bejaia.dz>
Date: Mon, 2 May 2011 15:12:17 +0100
Subject: [PATCH] Added Least Load Neighbors and another bulk algorithm

---
 loba_bulk.cpp | 78 +++++++++++++++++++++++++++++++++++++++++++++++++--
 options.cpp   |  5 +++-
 2 files changed, 80 insertions(+), 3 deletions(-)

diff --git a/loba_bulk.cpp b/loba_bulk.cpp
index 9af50cf..f5ec64e 100644
--- a/loba_bulk.cpp
+++ b/loba_bulk.cpp
@@ -1,4 +1,5 @@
 #include <xbt/log.h>
+#include <math.h>
 
 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(loba);
 
@@ -6,8 +7,81 @@ XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(loba);
 
 void loba_bulk::load_balance()
 {
-    // write code here...
-    xbt_die("Load-balancing algorithm \"bulk\" not implemented!");
+	float myLoad = get_load();
+
+	unsigned NbNwMinLoad = 0;
+	unsigned NbNwLowerLoad = 0;
+	unsigned NbNeighbours = pneigh.size();
+
+	double *S = new double[NbNeighbours];
+	for (unsigned i = 0; i < NbNeighbours; i++) 
+		S[i] = 0.0;
+	//What is the minimum and maximum load under myLoad?
+	float minLoad = myLoad;
+	for (unsigned i = 0; i < NbNeighbours; i++) {
+		if (pneigh[i]->get_load() < minLoad) {
+			minLoad = pneigh[i]->get_load();
+		}
+		if (pneigh[i]->get_load() < myLoad) {
+			NbNwLowerLoad++;
+		}
+	}
+	for (unsigned i = 0; i < NbNeighbours; i++)
+		if (pneigh[i]->get_load() == minLoad)
+			NbNwMinLoad++;
+
+	float maxLoad = minLoad;
+	for (unsigned i = 0; i < NbNeighbours; i++) {
+		if (pneigh[i]->get_load() > minLoad && pneigh[i]->get_load() < myLoad)
+			if (maxLoad < pneigh[i]->get_load())
+				maxLoad = pneigh[i]->get_load();
+	}
+
+	double alpha = 0.0;
+
+	if (NbNwLowerLoad && NbNwMinLoad < NbNwLowerLoad) //There is one or many neighbors with minimum load but not all neighbors have minimum load
+		alpha = (1. / ((double) NbNwMinLoad + 2));
+	if (NbNwMinLoad == NbNwLowerLoad) //All neighbors have minimum load
+		alpha = (1. / ((double) NbNwMinLoad + 1));
+	float myS = 0.;
+	//There exist underloaded neighbors
+	if (NbNwMinLoad && myLoad != 0.0) {
+		for (unsigned i = 0; i < NbNeighbours; i++) {
+			if (pneigh[i]->get_load() == minLoad) {
+				S[i] = floor(alpha * (myLoad - minLoad));
+				myS +=  S[i];
+			} else {
+				if (pneigh[i]->get_load() < myLoad) {
+					S[i] = floor(alpha * (myLoad - pneigh[i]->get_load()));
+					myS +=  S[i];
+				}
+			}
+		}
+		//Check assumption 4.2 (b) page 520
+		bool HaveToCorrectS = false;
+		for (unsigned i = 0; i < NbNeighbours; i++) {
+			if (pneigh[i]->get_load() < myLoad) { //
+				//Condition 4.6
+				if ((myLoad - myS) < (pneigh[i]->get_load() + S[i])) {
+					HaveToCorrectS = true;
+				}
+			}
+		}
+		if (HaveToCorrectS) {
+				for (unsigned i = 0; i < NbNeighbours; i++) {
+					while (((myLoad - myS) < pneigh[i]->get_load() + S[i]) && (S[i] > 0)) {
+						myS -= 1.0;
+						S[i] -= 1.0;
+					}
+				}
+		}
+	}//End there are underloaded neighbors;
+	for (unsigned i = 0 ; i < NbNeighbours ; i++) {
+                send(pneigh[i], S[i]);
+                XBT_DEBUG("sent to %s", pneigh[i]->get_name());
+        }
+
+	delete[] S;
 }
 
 // Local variables:
diff --git a/options.cpp b/options.cpp
index 9b1344a..3e0f92d 100644
--- a/options.cpp
+++ b/options.cpp
@@ -13,6 +13,7 @@ XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(main);
 #include "loba_besteffort.h"
 #include "loba_bulk.h"
 #include "loba_fairstrategy.h"
+#include "loba_lln.h"
 #include "loba_makhoul.h"
 #include "loba_makhoul2.h"
 #include "loba_simple.h"
@@ -80,10 +81,12 @@ namespace opt {
     {
         NOL_INSERT("besteffort", "balance with best effort strategy",
                    loba_besteffort);
-        NOL_INSERT("bulk", "describe your algorithm here...",
+        NOL_INSERT("bulk", "A multi-load-units assignation rule without ordering...",
                    loba_bulk);
         NOL_INSERT("fairstrategy", "balance with fair strategy",
                    loba_fairstrategy);
+        NOL_INSERT("lln", "Balance with less loaded neighbors without ordering-bulk method",
+                   loba_lln);
         NOL_INSERT("makhoul", "balance with Makhoul's PhD algorithm",
                    loba_makhoul);
         NOL_INSERT("makhoul2", "balance with Makhoul's source code",
-- 
2.39.5