/// <summary>
/// return the cost of the best solution so far.
/// </summary>
/// <returns></returns>
public double CostOfBssf()
{
if (_bssf != null)
{
return(_bssf.CostOfRoute());
}
return(-1D);
}
public string[] ThreeOptSolveProblem()
{
var results = new string[3];
// get initial bssf using default algorithm
int i, swap, temp, count = 0;
int[] perm = new int[_cities.Length];
_route = new List <City>();
Random rnd = new Random();
do
{
for (i = 0; i < perm.Length; i++) // create a random permutation template
{
perm[i] = i;
}
for (i = 0; i < perm.Length; i++)
{
swap = i;
while (swap == i)
{
swap = rnd.Next(0, _cities.Length);
}
temp = perm[i];
perm[i] = perm[swap];
perm[swap] = temp;
}
_route.Clear();
for (i = 0; i < _cities.Length; i++) // Now build the route using the random permutation
{
_route.Add(_cities[perm[i]]);
}
_bssf = new TspSolution(_route);
} while (CostOfBssf() == double.PositiveInfinity); // until a valid route is found
Stopwatch timer = new Stopwatch();
timer.Start();
count = 0;
TspSolution prevSolution = _bssf;
bool found = false;
do
{
double bestDist = _bssf.CostOfRoute();
found = false;
for (i = 0; i < _bssf.Route.Count - 2; i++)
{
for (int j = i + 1; j < _bssf.Route.Count - 1; j++)
{
for (int k = j + 1; k < _bssf.Route.Count; k++)
{
TspSolution newRoute1 = threeOptSwapA(_bssf, i, j, k);
TspSolution newRoute2 = threeOptSwapB(_bssf, i, j, k);
TspSolution newRoute3 = threeOptSwapC(_bssf, i, j, k);
TspSolution newRoute4 = twoOptSwap(_bssf, i, j);
TspSolution newRoute5 = twoOptSwap(_bssf, j, k);
TspSolution newRoute6 = twoOptSwap(_bssf, i, k);
double newDist1 = newRoute1.CostOfRoute();
double newDist2 = newRoute2.CostOfRoute();
double newDist3 = newRoute3.CostOfRoute();
double newDist4 = newRoute4.CostOfRoute();
double newDist5 = newRoute5.CostOfRoute();
double newDist6 = newRoute6.CostOfRoute();
if (isCompleteSolution(newRoute1) && newDist1 < bestDist && newDist1 <= newDist2 && newDist1 <= newDist3 && newDist1 <= newDist4 && newDist1 <= newDist5 && newDist1 <= newDist6)
{
prevSolution = _bssf;
_bssf = newRoute1;
found = true;
count++;
break;
}
if (isCompleteSolution(newRoute2) && newDist2 < bestDist && newDist2 <= newDist1 && newDist2 <= newDist3 && newDist2 <= newDist4 && newDist2 <= newDist5 && newDist2 <= newDist6)
{
prevSolution = _bssf;
_bssf = newRoute2;
found = true;
count++;
break;
}
if (isCompleteSolution(newRoute3) && newDist3 < bestDist && newDist3 <= newDist2 && newDist3 <= newDist1 && newDist3 <= newDist4 && newDist3 <= newDist5 && newDist3 <= newDist6)
{
prevSolution = _bssf;
_bssf = newRoute3;
found = true;
count++;
break;
}
if (isCompleteSolution(newRoute4) && newDist4 < bestDist && newDist4 <= newDist2 && newDist4 <= newDist1 && newDist4 <= newDist3 && newDist4 <= newDist5 && newDist4 <= newDist6)
{
prevSolution = _bssf;
_bssf = newRoute4;
found = true;
count++;
break;
}
if (isCompleteSolution(newRoute5) && newDist5 < bestDist && newDist5 <= newDist2 && newDist5 <= newDist1 && newDist5 <= newDist4 && newDist5 <= newDist3 && newDist5 <= newDist6)
{
prevSolution = _bssf;
_bssf = newRoute5;
found = true;
count++;
break;
}
if (isCompleteSolution(newRoute6) && newDist6 < bestDist && newDist6 <= newDist2 && newDist6 <= newDist1 && newDist6 <= newDist4 && newDist6 <= newDist5 && newDist6 <= newDist3)
{
prevSolution = _bssf;
_bssf = newRoute6;
found = true;
count++;
break;
}
}
if (found)
{
break;
}
}
if (found)
{
break;
}
}
} while (found);
timer.Stop();
results[Cost] = _bssf.CostOfRoute().ToString();
results[Time] = timer.Elapsed.ToString();
results[Count] = count.ToString();
return(results);
}
public string[] TwoOptSolveProblem()
{
var results = new string[3];
// get initial bssf using default algorithm
int i, swap, temp, count = 0;
int[] perm = new int[_cities.Length];
_route = new List <City>();
Random rnd = new Random();
do
{
for (i = 0; i < perm.Length; i++) // create a random permutation template
{
perm[i] = i;
}
for (i = 0; i < perm.Length; i++)
{
swap = i;
while (swap == i)
{
swap = rnd.Next(0, _cities.Length);
}
temp = perm[i];
perm[i] = perm[swap];
perm[swap] = temp;
}
_route.Clear();
for (i = 0; i < _cities.Length; i++) // Now build the route using the random permutation
{
_route.Add(_cities[perm[i]]);
}
_bssf = new TspSolution(_route);
} while (CostOfBssf() == double.PositiveInfinity); // until a valid route is found
Stopwatch timer = new Stopwatch();
timer.Start();
count = 0;
TspSolution prevSolution = _bssf;
bool found = false;
do
{
double bestDist = _bssf.CostOfRoute();
for (i = 0; i < _bssf.Route.Count; i++)
{
found = false;
for (int k = i + 1; k < _bssf.Route.Count; k++)
{
TspSolution newRoute = twoOptSwap(_bssf, i, k);
double newDist = newRoute.CostOfRoute();
if (isCompleteSolution(newRoute) && newDist < bestDist)
{
prevSolution = _bssf;
_bssf = newRoute;
found = true;
count++;
break;
}
}
if (found)
{
break;
}
}
} while (found);
timer.Stop();
results[Cost] = _bssf.CostOfRoute().ToString();
results[Time] = timer.Elapsed.ToString();
results[Count] = count.ToString();
return(results);
}