From 3358a469a36c44ca8998c00df04142463dac479d Mon Sep 17 00:00:00 2001
From: Fabian Becker <halfdan@xnorfz.de>
Date: Thu, 6 Nov 2014 11:27:32 +0100
Subject: [PATCH] Fix bug in PSO implementation.

---
 .../optimization/strategies/ParticleSwarmOptimization.java | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/eva2/optimization/strategies/ParticleSwarmOptimization.java b/src/eva2/optimization/strategies/ParticleSwarmOptimization.java
index 32ec6f55..6830a2d3 100644
--- a/src/eva2/optimization/strategies/ParticleSwarmOptimization.java
+++ b/src/eva2/optimization/strategies/ParticleSwarmOptimization.java
@@ -1478,23 +1478,24 @@ public class ParticleSwarmOptimization extends AbstractOptimizer implements java
     @Override
     public void setPopulation(Population pop) {
         this.population = pop;
-        if (pop.size() != pop.getTargetSize()) { // new particle count!
+        if (pop.size() > 0 && pop.size() != pop.getTargetSize()) { // new particle count!
             tracedVelocity = null;
             initializeByPopulation(null, false);
+            bestIndividual = pop.getBestEAIndividual();
         } else {
             for (int i = 0; i < pop.size(); i++) {
                 AbstractEAIndividual indy = pop.getEAIndividual(i);
                 if (indy == null) {
                     System.err.println("Error in PSO.setPopulation!");
-                } else if (!indy.hasData(partTypeKey)) {
+                } else if (!indy.hasData(this.partTypeKey)) {
                     initIndividualDefaults(indy, initialVelocity);
                     initIndividualMemory(indy);
                     indy.putData(indexKey, i);
                     indy.setIndividualIndex(i);
                 }
             }
+            bestIndividual = pop.getBestEAIndividual();
         }
-        bestIndividual = pop.getBestEAIndividual();
     }
 
     @Override