Corrected an erroneous comment.

src/solvers/MIPModel2.java

@@ -31,8 +31,7 @@ public final class MIPModel2 {
 
   // Model components.
   private final IloCplex mip;     // the MIP model
-  private final IloIntVar[][] x;  // x[i][j] = 1 if trans i & j are in the same
-                                  // cluster; x[i][i] = 1 if i anchors a cluster
+  private final IloIntVar[][] x;  // x[i][j] = 1 if trans i is in cluster j
   private final IloIntVar[][] y;  // y[i][j] = 1 if trans i & user j are
                                   // in the same cluster
   private final IloNumVar[][] z;  // z[i][j] is the objective contribution of