public Schedule FindBestSchedule(SortedDictionary <int, List <Job> > jobs, int level = 20, int populationSize = 100, int topPercentToKeep = 80, OpenShopGASchedulerSettings currentBestFit = null)
{
//first, define a population
var populationSet = new List <Schedule>();
var rand = new Random();
for (int i = 0; i < populationSize; i++)
{
var chromosome = ScheduleCourses(jobs, true);
var settings = new OpenShopGASchedulerSettings()
{
Chromosome = chromosome
};
var sched = new Schedule()
{
Courses = this.Schedule,
SchedulerName = nameof(OpenShopGAScheduler),
ScheduleSettings = settings,
};
var rating = GetRating(sched);
sched.Rating = rating;
populationSet.Add(sched);
}
var fittest = SelectFittest(populationSet, level, topPercentToKeep, currentBestFit);
return(fittest.OrderByDescending(s => s.Rating).First());
}
//------------------------------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------------------------------
public OpenShopGAScheduler(int paramID, Models.Preferences preferences, bool preferShortest = true, OpenShopGASchedulerSettings currentBestFit = null)
{
this.CurrentBestFit = currentBestFit;
this.Preferences = preferences;
SetUp(paramID);
MakeStartingPoint();
InitDegreePlan();
}
private List <OpenShopGASchedulerSettings> GetCrossOvers(OpenShopGASchedulerSettings parent1, OpenShopGASchedulerSettings parent2, int count)
{
var random = new Random();
var lowest = parent1.Chromosome.Count < parent2.Chromosome.Count ? parent1.Chromosome.Count : parent2.Chromosome.Count;
if (parent1.Chromosome.Count <= 0)
{
return new List <OpenShopGASchedulerSettings>()
{
parent1
}
}
;
var crossOvers = new List <OpenShopGASchedulerSettings>();
for (int i = 0; i < count; i++)
{
var crossOver = new OpenShopGASchedulerSettings()
{
Chromosome = new List <Job>()
};
foreach (var job in parent1.Chromosome)
{
crossOver.Chromosome.Add(job);
}
var randIndex = random.Next(lowest - 1);
//swap at this index
var old = crossOver.Chromosome[randIndex];
var newVal = crossOver.Chromosome[randIndex];
crossOver.Chromosome[randIndex] = newVal;
int jobToReplace = -1;
for (int j = 0; i < parent1.Chromosome.Count; i++)
{
if (crossOver.Chromosome[i] == newVal)
{
jobToReplace = i;
}
}
if (jobToReplace != -1)
{
crossOver.Chromosome[jobToReplace] = old;
}
crossOvers.Add(crossOver);
}
return(crossOvers);
}
public List <Schedule> SelectFittest(List <Schedule> populationSet, int level = 20, int topPercentToKeep = 95, OpenShopGASchedulerSettings currentBestFit = null)
{
if (level == 0 || populationSet.Count <= 2)
{
return(populationSet);
}
var rand = new Random();
Schedule topSchedule = null;
//select best from population
if (currentBestFit == null)
{
topSchedule = populationSet.OrderByDescending(s => s.Rating).First();
}
else
{
ScheduleCourse(currentBestFit.Chromosome);
topSchedule = new Schedule()
{
Courses = this.Schedule,
SchedulerName = nameof(OpenShopGAScheduler),
ScheduleSettings = currentBestFit,
};
var rating = GetRating(topSchedule);
topSchedule.Rating = rating;
}
var cutoff = populationSet.Count * topPercentToKeep / 100;
populationSet = populationSet.OrderByDescending(s => s.Rating).Take(cutoff).ToList();
if (populationSet.Contains(topSchedule))
{
populationSet.Remove(topSchedule);
}
List <Schedule> offSprings = new List <Schedule>();
while (populationSet.Count > 0)
{
var mate = populationSet.First();
//cross over
var crossOvers = GetCrossOvers(topSchedule.ScheduleSettings, mate.ScheduleSettings, 2);
foreach (var crossOver in crossOvers)
{
//mutate (swap with some other schedule in the population)
var randomPop = rand.Next(populationSet.Count - 1);
var randomToMutate = populationSet[randomPop];
var mutation = GetCrossOvers(crossOver, randomToMutate.ScheduleSettings, 1);
ScheduleCourse(mutation.First().Chromosome);
var offspring = new Schedule()
{
Courses = this.Schedule,
SchedulerName = nameof(OpenShopGAScheduler),
ScheduleSettings = crossOver,
};
var rating = GetRating(offspring);
offspring.Rating = rating;
offSprings.Add(offspring);
}
populationSet.Remove(mate);
}
return(SelectFittest(offSprings, level - 1));
}