Save/access a postsolved solution in memory

using System;
using System.IO;
using Optimizer;



namespace XPRSExamples
{
	class SaveSol
	{
		public static void Main(string[] args)
		{
			SaveSol example = new SaveSol();
			example.Run();
		}

		private void Run()
		{
			try
			{
				string sProblem=@"..\..\..\Data\burglar";     /* Problem name */
				string sOutFile="savesol.out"; /* Output file name */

				int nSol;                     /* Number of integer solutions found */
				double dBestObj;              /* Best objective value found */
				int nNodes;                   /* Number of nodes solved in the global search */
				int nActNodes;                /* Number of active nodes ignored by the search */
				int nLastNode;                /* Node at which the last integer solution was found */
				double dBestBnd;              /* Best bound found in the global search */
				int nGlStatus;                /* Global search status - complete, incomplete, etc */
				int i;                        /* Loop counter*/

				
				// open the output file
				// Delete the file if it exists.
				if (File.Exists(sOutFile)) 
				{
					File.Delete(sOutFile);
				}
				pOutput = new StreamWriter(sOutFile);

				// Initialise Optimizer
				XPRS.Init("");
				Console.WriteLine("{0}", XPRS.GetBanner());

				prob = new XPRSprob();

				// Tell Optimizer to call optimizermsg whenever a message is output
				prob.MessageCallbacks += new MessageCallback(this.OptimizerMsg);

				// Get and display the Optimizer version number
				Console.WriteLine("\nXpress Optimiser Subroutine Library Release {0}",prob.Version/100);

				// Allow no cuts - so the problem does not solve too quickly
				prob.CutStrategy = 0;
				
				// Read the problem file
        prob.MPSFormat = -1;
				prob.ReadProb(sProblem,"");

				// Tell Optimizer to postsolve every integer solution found, save it to memory and
				// print the solution values to the output file

				// Call function printsol whenever an integer solution is found
				prob.IntsolCallbacks += new IntsolCallback(this.PrintSol);

				// Get the number of columns and allocate space for the solution array
				gnCol = prob.Cols;
				gpIntSol = new double[gnCol];

				// Search for integer solutions
				Console.WriteLine("Solving problem {0}\n\n",sProblem);
                prob.MipOptimize();

				// Retrieve the results of the global search

				// Get the number of integer solutions found 
				nSol = prob.MIPSols;

				// Get the objective value of the best integer solution found
				dBestObj = prob.MIPObjVal;

				// Get the number of outstanding nodes
				nActNodes = prob.ActiveNodes;

				// Get the node at which the last feasible integer solution was found
				nLastNode = prob.MIPSolNode;

				// Get the number of nodes solved
				nNodes = prob.Nodes;

				// Get the value of the best bound
				dBestBnd = prob.BestBound;

				// Get the global status
				nGlStatus = (int)prob.MIPStatus;

				// Display the results of the global search

				switch (nGlStatus) 
				{
					case 3:
						Console.WriteLine("Global search incomplete\n\n");
						Console.WriteLine("   No integer solution found\n");
						Console.WriteLine("   {0} nodes searched\n",nNodes);
						Console.WriteLine("   {0} nodes remaining in search\n",nActNodes);
						Console.WriteLine("   Best bound {0}\n\n",dBestBnd);
						break;
					case 4:
						Console.WriteLine("Global search incomplete\n\n");
						Console.WriteLine("   {0} integer solution{1} found\n",nSol,(nSol==1) ? "" : "s");
						Console.WriteLine("   {0} nodes searched\n",nNodes);
						Console.WriteLine("   {0} nodes remaining in search\n",nActNodes);
						Console.WriteLine("   Best bound {0}\n\n",dBestBnd);
						Console.WriteLine("   Best integer solution at node {0}\n\n",nLastNode);
						Console.WriteLine("      Objective value {0}\n\n",dBestObj);
						Console.WriteLine("      Solution values\n");
						for (i=0; i<gnCol; i++)
							Console.WriteLine("          x[{0}]={1}\n",i,gpIntSol[i]);
						Console.WriteLine("\n");
						break;
					case 5:
						Console.WriteLine("Global search complete\n\n");
						Console.WriteLine("   No integer solution found\n");
						Console.WriteLine("   {0} nodes searched\n",nNodes);
						Console.WriteLine("   Best bound {0}\n",dBestBnd);
						break;
					case 6:
						Console.WriteLine("Global search complete\n\n");
						Console.WriteLine("   {0} nodes searched\n",nNodes);
						Console.WriteLine("   {0} integer solution%s found\n\n",nSol,(nSol==1) ? "" : "s");
						Console.WriteLine("   Best integer solution at node {0}\n\n",nLastNode);
						Console.WriteLine("      Objective value {0}\n\n",dBestObj);
						Console.WriteLine("      Solution values\n");
						for (i=0; i<gnCol; i++)
							Console.WriteLine("          x[{0}]={1}\n",i,gpIntSol[i]);
						Console.WriteLine("\n");
						break;
					default:
						Console.WriteLine("Global search did not take place\n\n");
						break;
				}
			}

			catch (XPRSException e)
			{
				Console.WriteLine(e.ToString());
        throw e;
			}
			finally
			{
				prob.Destroy();
				pOutput.Close();
				XPRS.Free();
			}
		}

		public void OptimizerMsg (XPRSprob prob, object data, string message, int len, int msglvl)
		{
			switch(msglvl)
			{
				case 3:
				case 4:
					Console.WriteLine ("{0}" + message, data);
					break;
			}
		}

		public void PrintSol(XPRSprob prob, object data)
		{
			int nNodeNum;            // Current node number
			double dObjVal;          // Objective value of the nodal integer solution
			int i;                   // Loop counter

			// Get the current node number
			nNodeNum = prob.Nodes;
	
			// Get the objective value of the current integer solution
			dObjVal = prob.MIPObjVal;

			// Retrieve the postsolved solution values from memory
			prob.GetSol(gpIntSol, null, null, null);

			// Print the solution to the output file
			pOutput.Write("Node " + nNodeNum + "\n");
			pOutput.Write("   Integer solution has objective value " + dObjVal + "\n");
			pOutput.Write("   Postsolved solution values are:\n");
			for (i=0; i<gnCol; i++)
				pOutput.Write("      x[" + i + "]=" + gpIntSol[i] + "\n");
			pOutput.Write("\n");
		}

		private XPRSprob prob;

		private int gnCol;                        // Numberfile of columns in the problem matrix
		private double[] gpIntSol;                // Integer solution values
		private StreamWriter pOutput;

	}
}