} // END CreateMasterILP
public static void Main(string[] args)
{
try
{
string fileName = "../../../../examples/data/atsp.dat";
// Check the command line arguments
if (args.Length != 1 && args.Length != 2)
{
Usage();
return;
}
if (!(args[0].Equals("0") || args[0].Equals("1")))
{
Usage();
return;
}
bool sepFracSols = (args[0].ToCharArray()[0] == '0' ? false : true);
if (sepFracSols)
{
System.Console.WriteLine("Benders' cuts separated to cut off: " +
"Integer and fractional infeasible solutions.");
}
else
{
System.Console.WriteLine("Benders' cuts separated to cut off: " +
"Only integer infeasible solutions.");
}
if (args.Length == 2)
{
fileName = args[1];
}
// Read arc_costs from data file (17 city problem)
Data data = new Data(fileName);
// create master ILP
int numNodes = data.numNodes;
Cplex cplex = new Cplex();
IIntVar[][] x = new IIntVar[numNodes][];
CreateMasterILP(cplex, data, x);
// Create workerLP for Benders' cuts separation
WorkerLP workerLP = new WorkerLP(numNodes);
// Set up the cut callback to be used for separating Benders' cuts
cplex.SetParam(Cplex.Param.Preprocessing.Presolve, false);
// Set the maximum number of threads to 1.
// This instruction is redundant: If MIP control callbacks are registered,
// then by default CPLEX uses 1 (one) thread only.
// Note that the current example may not work properly if more than 1 threads
// are used, because the callback functions modify shared global data.
// We refer the user to the documentation to see how to deal with multi-thread
// runs in presence of MIP control callbacks.
cplex.SetParam(Cplex.Param.Threads, 1);
// Turn on traditional search for use with control callbacks
cplex.SetParam(Cplex.Param.MIP.Strategy.Search, Cplex.MIPSearch.Traditional);
cplex.Use(new BendersLazyConsCallback(x, workerLP));
if (sepFracSols)
{
cplex.Use(new BendersUserCutCallback(x, workerLP));
}
// Solve the model and write out the solution
if (cplex.Solve())
{
System.Console.WriteLine();
System.Console.WriteLine("Solution status: " + cplex.GetStatus());
System.Console.WriteLine("Objective value: " + cplex.ObjValue);
if (cplex.GetStatus().Equals(Cplex.Status.Optimal))
{
// Write out the optimal tour
int i, j;
double[][] sol = new double[numNodes][];
int[] succ = new int[numNodes];
for (j = 0; j < numNodes; ++j)
{
succ[j] = -1;
}
for (i = 0; i < numNodes; ++i)
{
sol[i] = cplex.GetValues(x[i]);
for (j = 0; j < numNodes; ++j)
{
if (sol[i][j] > 1e-03)
{
succ[i] = j;
}
}
}
System.Console.WriteLine("Optimal tour:");
i = 0;
while (succ[i] != 0)
{
System.Console.Write(i + ", ");
i = succ[i];
}
System.Console.WriteLine(i);
}
else
{
System.Console.WriteLine("Solution status is not Optimal");
}
}
else
{
System.Console.WriteLine("No solution available");
}
workerLP.End();
cplex.End();
}
catch (ILOG.Concert.Exception ex)
{
System.Console.WriteLine("Concert Error: " + ex);
}
catch (InputDataReader.InputDataReaderException ex)
{
System.Console.WriteLine("Data Error: " + ex);
}
catch (System.IO.IOException ex)
{
System.Console.WriteLine("IO Error: " + ex);
}
} // END Main
internal BendersUserCutCallback(IIntVar[][] x, WorkerLP workerLP)
{
this.x = x;
this.workerLP = workerLP;
numNodes = x.Length;
}
internal BendersUserCutCallback(IIntVar[][] x, WorkerLP workerLP)
{
this.x = x;
this.workerLP = workerLP;
numNodes = x.Length;
}
public static void Main(string[] args)
{
try
{
string fileName = "../../../../examples/data/atsp.dat";
// Check the command line arguments
if ( args.Length != 1 && args.Length != 2 )
{
Usage();
return;
}
if ( ! (args[0].Equals("0") || args[0].Equals("1")) )
{
Usage();
return;
}
bool sepFracSols = (args[0].ToCharArray()[0] == '0' ? false : true);
if ( sepFracSols )
{
System.Console.WriteLine("Benders' cuts separated to cut off: " +
"Integer and fractional infeasible solutions.");
}
else
{
System.Console.WriteLine("Benders' cuts separated to cut off: " +
"Only integer infeasible solutions.");
}
if ( args.Length == 2 ) fileName = args[1];
// Read arc_costs from data file (17 city problem)
Data data = new Data(fileName);
// create master ILP
int numNodes = data.numNodes;
Cplex cplex = new Cplex();
IIntVar[][] x = new IIntVar[numNodes][];
CreateMasterILP(cplex, data, x);
// Create workerLP for Benders' cuts separation
WorkerLP workerLP = new WorkerLP(numNodes);
// Set up the cut callback to be used for separating Benders' cuts
cplex.SetParam(Cplex.Param.Preprocessing.Presolve, false);
// Set the maximum number of threads to 1.
// This instruction is redundant: If MIP control callbacks are registered,
// then by default CPLEX uses 1 (one) thread only.
// Note that the current example may not work properly if more than 1 threads
// are used, because the callback functions modify shared global data.
// We refer the user to the documentation to see how to deal with multi-thread
// runs in presence of MIP control callbacks.
cplex.SetParam(Cplex.Param.Threads, 1);
// Turn on traditional search for use with control callbacks
cplex.SetParam(Cplex.Param.MIP.Strategy.Search, Cplex.MIPSearch.Traditional);
cplex.Use(new BendersLazyConsCallback(x, workerLP));
if ( sepFracSols )
cplex.Use(new BendersUserCutCallback(x, workerLP));
// Solve the model and write out the solution
if ( cplex.Solve() )
{
System.Console.WriteLine();
System.Console.WriteLine("Solution status: " + cplex.GetStatus());
System.Console.WriteLine("Objective value: " + cplex.ObjValue);
if ( cplex.GetStatus().Equals(Cplex.Status.Optimal) )
{
// Write out the optimal tour
int i, j;
double[][] sol = new double[numNodes][];
int[] succ = new int[numNodes];
for (j = 0; j < numNodes; ++j)
succ[j] = -1;
for (i = 0; i < numNodes; ++i)
{
sol[i] = cplex.GetValues(x[i]);
for (j = 0; j < numNodes; ++j)
{
if ( sol[i][j] > 1e-03 ) succ[i] = j;
}
}
System.Console.WriteLine("Optimal tour:");
i = 0;
while ( succ[i] != 0 )
{
System.Console.Write(i + ", ");
i = succ[i];
}
System.Console.WriteLine(i);
}
else
{
System.Console.WriteLine("Solution status is not Optimal");
}
}
else
{
System.Console.WriteLine("No solution available");
}
workerLP.End();
cplex.End();
}
catch (ILOG.Concert.Exception ex)
{
System.Console.WriteLine("Concert Error: " + ex);
}
catch (InputDataReader.InputDataReaderException ex)
{
System.Console.WriteLine("Data Error: " + ex);
}
catch (System.IO.IOException ex)
{
System.Console.WriteLine("IO Error: " + ex);
}
}
