Termination Problem: redundant ObjFunc evaluation

[Matthew Wall]

if you use the 'score' method instead of the invoking your objective 
function directly then you will not have to re-evaluate. 
GAGenome::score caches the score returned by the objective function 
(and well-behaved genomes mark the cache as dirty when they change 
state).

so instead of

   double y = objective(genome);

do this:

   double y = ga.statistics().bestIndividual().score();



>Hi All,
>I'm trying to find a better way to perform the terminate function.
>At the moment I need to terminate on a generation limit, but also when a
>solution falls within a user specified tolerance. The performance
>bottleneck happens here. You'll notice in the code snippet that I
>re-evaluate the genome in order to get an objective value, which I
>should already have. Is there a direct way to get the objective value,
>without re-evaluating as shown below?
>Many thanks,
>Martin
>
>#define TOLERANCE 0.00001
>
>GABoolean terminate(GAGeneticAlgorithm & ga)
>{
>
>  GABin2DecGenome& genome
>= (GABin2DecGenome &)ga.statistics().bestIndividual();
>  double y = objective(genome);
>
>  GABoolean bWithinTolerance = ((fabs(y) <= TOLERANCE ) ? gaTrue :
>gaFalse );
>  GABoolean bGeneration = ((ga.generation() < ga.nGenerations()) ?
>gaFalse : gaTrue);
>
>  if ((bWithinTolerance == gaTrue)||
>   (bGeneration == gaTrue))
>  {
>   if (bWithinTolerance == gaTrue)
>   {
>    cout << "Tolerance achieved: " << TOLERANCE << "\n";
>   }
>   cout << "Terminating on generation: " << ga.generation() << '\n';
>   return gaTrue;
>  }
>
>  return gaFalse;
>}