public Solution ImproveSolution(Solution initialSolution, List<Customer> selected, List<Route> routes)
{
if (selected == null)
return initialSolution;
var oldDist = initialSolution.TotalDistance();
Solution bestSolution = initialSolution;
foreach (var c in selected)
{
foreach (var r in routes)
{
var transfer = BestInsertionPlaceCzech2001(initialSolution, c, r);
if(transfer.Value < oldDist)
{
bestSolution = transfer.Key;
oldDist = transfer.Value;
}
}
}
return bestSolution;
}
public static List<double> ComputeGains(ref Solution p1, ref Solution p2, ref Solution p3, ref Solution p12, ref Solution p23, ref Solution p31, ref Solution p123,
int max_iters = 30, Update update = null, VrpSolver solver = null)
{
if (solver == null) solver = DefaultSolver;
/////
for (var i = 0; i < max_iters; ++i)
{
p1 = solver.Solve(p1.Problem, p1);
p2 = solver.Solve(p2.Problem, p2);
p3 = solver.Solve(p3.Problem, p3);
p12 = solver.Solve(p12.Problem, p12);
p23 = solver.Solve(p23.Problem, p23);
p31 = solver.Solve(p31.Problem, p31);
p123 = solver.Solve(p123.Problem, p123);
var v1 = p1.TotalDistance();
var v2 = p2.TotalDistance();
var v3 = p3.TotalDistance();
var v12 = p12.TotalDistance();
var v23 = p23.TotalDistance();
var v31 = p31.TotalDistance();
var v123 = p123.TotalDistance();
var phi1 = 1.0 * 3.0 / v1 + 1.0 / 6.0 * (v12 - v2) + 1.0 / 6.0 * (v31 - v3) + 1.0 / 3.0 * (v123 - v23);
var phi2 = 1.0 * 3.0 / v2 + 1.0 / 6.0 * (v23 - v3) + 1.0 / 6.0 * (v12 - v1) + 1.0 / 3.0 * (v123 - v31);
var phi3 = 1.0 * 3.0 / v3 + 1.0 / 6.0 * (v31 - v1) + 1.0 / 6.0 * (v23 - v2) + 1.0 / 3.0 * (v123 - v12);
p1.Phi = v1 - phi1;
p2.Phi = v2 - phi2;
p3.Phi = v3 - phi3;
update(max_iters, i);
}
return null;
}
public KeyValuePair<Solution, double> BestInsertionPlaceCzech2001(Solution solution, Customer customer, Route route)
{
// Route customerRoute = solution.Routes[customerRouteIndex];
// Customer customer = (Customer)customerRoute.RouteList[cusotomerIndex];
// Route targetRoute = solution.Routes[targetRouteIndex];
//int bestSolution = -1;
double bestCost = solution.TotalDistance();
//solution.Routes[cusotomerIndex] = customerRoute.Copy();
//solution.Routes[cusotomerIndex].RouteList.RemoveAt(cusotomerIndex);
var routeIndex = route.Index();
var newSolution = solution.Copy();
var oldRouteIdx = customer.Route.Index();
var oldRoute = newSolution.Routes[oldRouteIdx].Copy();
oldRoute.RemoveAt(customer.Index());
newSolution.Routes[oldRouteIdx] = oldRoute;
Solution bestSolutionCopy = null;
for (int i = 1; i < route.RouteList.Count; ++i)
{
var newRoute = solution.Routes[routeIndex].Copy();
newRoute.InsertCustomer(customer, i);
newSolution.Routes[routeIndex] = newRoute;
double newCost = newSolution.TotalDistance();
if (newRoute.IsFeasible() && newCost < bestCost)
{
bestSolutionCopy = newSolution.Copy();
bestCost = newCost;
}
}
return new KeyValuePair<Solution, double>(bestSolutionCopy, bestCost);
}