private static int[] MoveQueens(int[] randomState, int costToSolverHeuristic, double temperature)
{
var random = new Random();
var randomStateLength = randomState.Length;
while (true)
{
var randomCol = random.Next(randomStateLength);
var randomRow = random.Next(randomStateLength);
var temporaryRow = randomState[randomCol];
randomState[randomCol] = randomRow;
var heuristicCost = GenerateHeuristics.GetHeuristicCost(randomState);
if (heuristicCost < costToSolverHeuristic)
{
return(randomState);
}
var distanceToSolver = costToSolverHeuristic - heuristicCost;
var probabilityAccepted = Math.Min(1, Math.Exp(distanceToSolver / temperature));
if (random.NextDouble() < probabilityAccepted)
{
return(randomState);
}
randomState[randomCol] = temporaryRow;
}
}
/*
* annealing = processo de aquecimento de metais, vidros, etc. seguido de resfriamento lento e gradual, com objetivo de tornar o material mais duro;
* simulated =reproduzido por meio de um modelo, simulado;
* scheduling =arranjo de eventos no tempo, escalonamento.
*/
public static IEnumerable <int> Solve(int nQueens, int maxIterations, double temperature, double variableCoolingFactor)
{
var randomState = GenerateHeuristics.GenerateRandomState(nQueens);
var heuristicCost = GenerateHeuristics.GetHeuristicCost(randomState);
var count = 0;
var countheristic = 0;
for (var i = 0; i < maxIterations && heuristicCost > 0; i++)
{
randomState = MoveQueens(randomState, heuristicCost, temperature);
heuristicCost = GenerateHeuristics.GetHeuristicCost(randomState);
temperature = Math.Max(temperature * variableCoolingFactor, 0.01);
count++;
countheristic += heuristicCost;
Console.WriteLine("Custo da Heuristica : " + heuristicCost);
}
Console.WriteLine("Custo Total da Heuristica : " + countheristic);
Console.WriteLine("Numero de Iterações: " + count);
return(heuristicCost == 0 ? randomState : null);
}