/// <summary>
/// Returns the customer that least increases the length of the given route.
/// </summary>
/// <param name="problem"></param>
/// <param name="route"></param>
/// <param name="customers"></param>
/// <param name="costs"></param>
/// <returns></returns>
public static CheapestInsertionResult CalculateBestPlacement(
IProblemWeights problem,
IRoute route,
ICollection <int> customers,
IInsertionCosts costs)
{
// initialize the best placement result.
CheapestInsertionResult best = new CheapestInsertionResult();
best.Increase = float.MaxValue;
// loop over all customers in the route.
if (route.Count > 0)
{ // there have to be at least two customers.
IEnumerator <int> route_enumerator = route.GetEnumerator();
if (!route_enumerator.MoveNext())
{ // this route is empty
throw new ArgumentException("Route needs to be initialized with at least two customers!");
}
int customer_before = route_enumerator.Current;
int customer_after = -1;
while (route_enumerator.MoveNext())
{ // keep moving!
customer_after = route_enumerator.Current;
InsertionCost cost = costs.PopCheapest(customer_before, customer_after);
bool found = false;
while (!found)
{ // test if the costs are empty.
if (cost == null)
{ // re-initialize the costs with all customers under consideration.
foreach (int customer in customers)
{
costs.Add(customer_before, customer_after, customer,
(float)problem.WeightMatrix[customer_before][customer] +
(float)problem.WeightMatrix[customer][customer_after] -
(float)problem.WeightMatrix[customer_before][customer_after]);
}
// pop the cheapest again!
cost = costs.PopCheapest(customer_before, customer_after);
}
else if (customers.Contains(cost.Customer))
{ // the customer is found!
found = true;
}
else
{ // pop the cheapest again!
cost = costs.PopCheapest(customer_before, customer_after);
}
}
if (cost.Cost < best.Increase)
{ // the costs is better than the current cost!
best = new CheapestInsertionResult()
{
Customer = cost.Customer,
CustomerAfter = customer_after,
CustomerBefore = customer_before,
Increase = cost.Cost
};
if (best.Increase == 0)
{ // immidiately return if smaller than epsilon.
return(best);
}
}
// set the after to the before.
customer_before = route_enumerator.Current;
}
// if the round is a round try first-last.
if (route.IsRound)
{ // the route is a round!
customer_after = route.First;
InsertionCost cost = costs.PopCheapest(customer_before, customer_after);
bool found = false;
while (!found)
{ // test if the costs are empty.
if (cost == null)
{ // re-initialize the costs with all customers under consideration.
foreach (int customer in customers)
{
costs.Add(customer_before, customer_after, customer,
(float)problem.WeightMatrix[customer_before][customer] +
(float)problem.WeightMatrix[customer][customer_after] -
(float)problem.WeightMatrix[customer_before][customer_after]);
}
// pop the cheapest again!
cost = costs.PopCheapest(customer_before, customer_after);
}
else if (customers.Contains(cost.Customer))
{ // the customer is found!
found = true;
}
else
{ // pop the cheapest again!
cost = costs.PopCheapest(customer_before, customer_after);
}
}
if (cost.Cost < best.Increase)
{ // the costs is better than the current cost!
best = new CheapestInsertionResult()
{
Customer = cost.Customer,
CustomerAfter = customer_after,
CustomerBefore = customer_before,
Increase = cost.Cost
};
if (best.Increase == 0)
{ // immidiately return if smaller than epsilon.
return(best);
}
}
}
}
else
{ // route needs to be initialized.
throw new ArgumentException("Route needs to be initialized with at least two customers!");
}
// return result.
return(best);
}
/// <summary>
/// Returns the customer that least increases the length of the given route.
/// </summary>
/// <param name="problem"></param>
/// <param name="route"></param>
/// <param name="customers"></param>
/// <param name="costs"></param>
/// <returns></returns>
public static CheapestInsertionResult CalculateBestPlacement(
IProblemWeights problem,
IRoute route,
ICollection<int> customers,
IInsertionCosts costs)
{
// initialize the best placement result.
CheapestInsertionResult best = new CheapestInsertionResult();
best.Increase = float.MaxValue;
// loop over all customers in the route.
if (route.Count > 0)
{ // there have to be at least two customers.
IEnumerator<int> route_enumerator = route.GetEnumerator();
if (!route_enumerator.MoveNext())
{ // this route is empty
throw new ArgumentException("Route needs to be initialized with at least two customers!");
}
int customer_before = route_enumerator.Current;
int customer_after = -1;
while (route_enumerator.MoveNext())
{ // keep moving!
customer_after = route_enumerator.Current;
InsertionCost cost = costs.PopCheapest(customer_before, customer_after);
bool found = false;
while(!found)
{ // test if the costs are empty.
if (cost == null)
{ // re-initialize the costs with all customers under consideration.
foreach (int customer in customers)
{
costs.Add(customer_before, customer_after, customer,
(float)problem.WeightMatrix[customer_before][customer] +
(float)problem.WeightMatrix[customer][customer_after] -
(float)problem.WeightMatrix[customer_before][customer_after]);
}
// pop the cheapest again!
cost = costs.PopCheapest(customer_before, customer_after);
}
else if (customers.Contains(cost.Customer))
{ // the customer is found!
found = true;
}
else
{ // pop the cheapest again!
cost = costs.PopCheapest(customer_before, customer_after);
}
}
if (cost.Cost < best.Increase)
{ // the costs is better than the current cost!
best = new CheapestInsertionResult()
{
Customer = cost.Customer,
CustomerAfter = customer_after,
CustomerBefore = customer_before,
Increase = cost.Cost
};
if (best.Increase == 0)
{ // immidiately return if smaller than epsilon.
return best;
}
}
// set the after to the before.
customer_before = route_enumerator.Current;
}
// if the round is a round try first-last.
if (route.IsRound)
{ // the route is a round!
customer_after = route.First;
InsertionCost cost = costs.PopCheapest(customer_before, customer_after);
bool found = false;
while (!found)
{ // test if the costs are empty.
if (cost == null)
{ // re-initialize the costs with all customers under consideration.
foreach (int customer in customers)
{
costs.Add(customer_before, customer_after, customer,
(float)problem.WeightMatrix[customer_before][customer] +
(float)problem.WeightMatrix[customer][customer_after] -
(float)problem.WeightMatrix[customer_before][customer_after]);
}
// pop the cheapest again!
cost = costs.PopCheapest(customer_before, customer_after);
}
else if (customers.Contains(cost.Customer))
{ // the customer is found!
found = true;
}
else
{ // pop the cheapest again!
cost = costs.PopCheapest(customer_before, customer_after);
}
}
if (cost.Cost < best.Increase)
{ // the costs is better than the current cost!
best = new CheapestInsertionResult()
{
Customer = cost.Customer,
CustomerAfter = customer_after,
CustomerBefore = customer_before,
Increase = cost.Cost
};
if (best.Increase == 0)
{ // immidiately return if smaller than epsilon.
return best;
}
}
}
}
else
{ // route needs to be initialized.
throw new ArgumentException("Route needs to be initialized with at least two customers!");
}
// return result.
return best;
}
