2 files changed, 8 insertions, 3 deletions

diff --git a/src/explicitsimulation.cpp b/src/explicitsimulation.cpp
index 98df0b0..95b721b 100644
--- a/src/explicitsimulation.cpp
+++ b/src/explicitsimulation.cpp
@@ -13,12 +13,13 @@ using namespace Bu;
 
 Genetic::ExplicitSimulation::ExplicitSimulation( Genetic::Operator *pOper,
                 Genetic::FitnessFunction *pFunc, int iThreads, int iPopSize,
-                float fKeep, float fRandom, bool bKeepBest ) :
+                float fKeep, float fRandom, bool bKeepBest, bool bRecalcSurvivors ) :
         pOper( pOper ),
         iPopSize( iPopSize ),
         fKeep( fKeep ),
         fRandom( fRandom ),
         bKeepBest( bKeepBest ),
+        bRecalcSurvivors( bRecalcSurvivors ),
         bRunning( true )
 {
         for( int j = 0; j < iPopSize; j++ )
@@ -102,7 +103,10 @@ void Genetic::ExplicitSimulation::timestep()
 
         // Refill the population
         mFitness.lock();
-        hFitness = hTempFitness;
+        if( bRecalcSurvivors )
+                hFitness.clear();
+        else
+                hFitness = hTempFitness;
         mFitness.unlock();
         xPop.clear();
         xPop.timestep();
diff --git a/src/explicitsimulation.h b/src/explicitsimulation.h
index e71b489..78cb904 100644
--- a/src/explicitsimulation.h
+++ b/src/explicitsimulation.h
@@ -18,7 +18,7 @@ namespace Genetic
         public:
                 ExplicitSimulation( Operator *pOper, FitnessFunction *pFunc,
                                 int iThreads, int iPopSize, float fKeep, float fRandom,
-                                bool bKeepBest=true );
+                                bool bKeepBest=true, bool bRecalcSurvivors=false );
                 virtual ~ExplicitSimulation();
 
                 void timestep();
@@ -47,6 +47,7 @@ namespace Genetic
                 float fKeep;
                 float fRandom;
                 bool bKeepBest;
+                bool bRecalcSurvivors;
                 typedef Bu::Hash<Genetic::PhenotypeId, double> FitnessHash;
                 FitnessHash hFitness;
                 double dMinFitness;