Updated to ACOTSP 1.03

Author: A. Wilke

README.md

@@ -1,7 +1,7 @@
 ACOTSPJava
 ==========
 
-A Java implementation of ACO algorithms for the TSP
+A Java implementation of ACO algorithms for the TSP  
 
 
 
@@ -16,20 +16,31 @@ https://github.com/adibaba/ACOTSPJava/
 
 
 
-Project information
--------------------
-
-The code is based on the ACOTSP project of Thomas Stuetzle:  
-ACO algorithms for the TSP  
-http://iridia.ulb.ac.be/~mdorigo/ACO/aco-code/public-software.html
+Usage
+-----
 
 You have to include the Apache Commons CLI library 1.2  
 http://commons.apache.org/proper/commons-cli/
 
+- Download the file  
+http://archive.apache.org/dist/commons/cli/binaries/commons-cli-1.2-bin.tar.gz
+- Copy the file 'commons-cli-1.2.jar' to your project directory
+- Add the library  
+In Eclipse: Right-click on jar-file -> 'Build Path' -> 'Add to Build Path'
+
 
 
-Contact information
+Project information
 -------------------
 
+The code is based on the ACOTSP project of Thomas Stuetzle:  
+ACO algorithms for the TSP, version 1.03  
+http://www.aco-metaheuristic.org/aco-code
+
+
+
+Contact
+-------
+
 Adrian Wilke  
 http://adrianwilke.de/

src/de/adrianwilke/acotspjava/LocalSearch.java

@@ -119,7 +119,7 @@ static void two_opt_first(int[] tour)
 	int pos_c1, pos_c2; /* positions of cities c1, c2 */
 	int i, j, h, l;
 	int help;
-	boolean improve_node, improvement_flag;
+	boolean improvement_flag;
 	int h1 = 0, h2 = 0, h3 = 0, h4 = 0;
 	int radius; /* radius of nn-search */
 	int gain = 0;
@@ -147,7 +147,6 @@ static void two_opt_first(int[] tour)
 		// DEBUG ( assert ( c1 < Tsp.n && c1 >= 0); )
 		if (dlb_flag && dlb[c1])
 		    continue;
-		improve_node = false;
 		pos_c1 = pos[c1];
 		s_c1 = tour[pos_c1 + 1];
 		radius = Tsp.instance.distance[c1][s_c1];
@@ -164,7 +163,6 @@ static void two_opt_first(int[] tour)
 			    h2 = s_c1;
 			    h3 = c2;
 			    h4 = s_c2;
-			    improve_node = true;
 			    gotoExchange = true;
 			    break;
 			}
@@ -198,7 +196,6 @@ static void two_opt_first(int[] tour)
 				h2 = c1;
 				h3 = p_c2;
 				h4 = c2;
-				improve_node = true;
 				gotoExchange = true;
 				break;
 			    }
@@ -207,7 +204,13 @@ static void two_opt_first(int[] tour)
 		    }
 		}
 
-		if (improve_node || gotoExchange) {
+		if (!gotoExchange) {
+		    /* No exchange */
+		    dlb[c1] = true;
+		    continue;
+		}
+
+		if (gotoExchange) {
 		    gotoExchange = false;
 		    improvement_flag = true;
 		    dlb[h1] = false;

src/de/adrianwilke/acotspjava/Tsp.java

@@ -119,9 +119,9 @@ static int ceil_distance(int i, int j)
     {
 	double xd = instance.nodeptr[i].x - instance.nodeptr[j].x;
 	double yd = instance.nodeptr[i].y - instance.nodeptr[j].y;
-	double r = Math.sqrt(xd * xd + yd * yd) + 0.000000001;
+	double r = Math.sqrt(xd * xd + yd * yd);
 
-	return (int) r;
+	return (int) Math.ceil(r);
     }
 
     static int geo_distance(int i, int j)