public void FindRoute(ref double[,] existingPheromones)
{
int[] path = new int[Costs.GetLength(0)];
HashSet <int> visited = new HashSet <int>();
// Choose a random city to start from
path[0] = random.Next(path.Length);
visited.Add(path[0]);
// Is a path possible?
bool success = FindRoute(0, ref path, visited, ref existingPheromones);
if (success)
{
// If so, store that path.
AntRoute = path;
// Find and store the route cost
StoreRouteCost();
}
else
{
Console.WriteLine("Setting Route to null. Edit this output to debug.");
AntRoute = null;
RouteCost = Double.MaxValue;
}
}
// Follows a route
// Returns a new matrix with the same values, changed so that
// the route from node i to node j has been followed. Makes it
// so that nothing from i or to j will be followed again. Also
// makes it so that the route from j to the beginning node can't
// be followed. Returns a reduced matrix.
public Matrix FollowRoute(int i, int j)
{
double[,] costs = Costs.Clone() as double[, ];
for (int k = 0; k < Costs.GetLength(0); k++)
{
costs[i, k] = Double.PositiveInfinity;
costs[k, j] = Double.PositiveInfinity;
}
// Make it so that it can't go to the start city (unless this is the last city
if (CitiesVisited < Cities.Length - 2)
{
costs[j, 0] = Double.PositiveInfinity;
}
return(new Matrix(Cities, costs, LowerBound, CitiesVisited + 1).Reduce());
}
public double[,] solveUV(out int cycles)
{
//Account for minimum delivery
adjustMinimumDelivery_FromSupplyAndDemand(false); //Subtract away
//Get dimensions
int rows = Costs.GetLength(0);
int cols = Costs.GetLength(1);
//Get Northwest approximation
double[,] solutionCurr = solveNorthWest(false);
//Cycle until end condion met
cycles = 0; //For statistics
while (true)
{
#region Calculate UV values
double[] u;
double[] v;
calculateUV_Values(solutionCurr, out u, out v);
#endregion
#region Calculate penalty values, track location of greatest penalty
double[,] penalties = new double[rows, cols];
int rMax = -1;
int cMax = -1;
double penaltyMax = double.NegativeInfinity;
bool allNegative = true;
//Calculate penalties
for (int r = 0; r < rows; r++)
{
for (int c = 0; c < cols; c++)
{
//Calculate only for unassigned cells
if (solutionCurr[r, c] == 0)
{
//Get and store value
double penalty = u[r] + v[c] - Costs[r, c];
penalties[r, c] = penalty;
//Check sign
if (penalty > 0)
{
allNegative = false;
}
//Check for max
if (penalty > penaltyMax)
{
penaltyMax = penalty;
rMax = r;
cMax = c;
}
}
}
}
#endregion
//Check end condion
if (allNegative)
{
//Finished
break;
}
#region Generate new iteration of solution
//Identify loop
int rLoopStart = rMax;
int cLoopStart = cMax;
int[,] loop = findLoop(solutionCurr, rLoopStart, cLoopStart);
//Get lowest number in "negative" group (odd entries of loop)
double minValue = double.PositiveInfinity;
for (int p = 0; p < loop.GetLength(0); p++)
{
//Get cell value
int r = loop[p, 0];
int c = loop[p, 1];
//Determine current operation
if (p % 2 == 1) //odd (negative operation numbers)
{
if (solutionCurr[r, c] < minValue)
{
minValue = solutionCurr[r, c];
}
}
}
//Adjust current solution
for (int p = 0; p < loop.GetLength(0); p++)
{
//Get cell value
int r = loop[p, 0];
int c = loop[p, 1];
//Determine current operation
if (p % 2 == 0) //even or zero
{
//Add the minimum value to the solution
solutionCurr[r, c] += minValue;
}
else //odd
{
//Remove the minimum value from the solution
solutionCurr[r, c] -= minValue;
}
}
#endregion
cycles++;
}
//Account for minimum delivery
addMinimumDelivery_ToSolution(solutionCurr);
adjustMinimumDelivery_FromSupplyAndDemand(true); //Add back
return(solutionCurr);
}
