/********************************************************
  Xpress-BCL C# Example Problems
  ==============================

  file xbdelvr.cs
  ````````````````
  Transportation problem.

  (c) 2008-2024 Fair Isaac Corporation
      authors: S.Heipcke, D.Brett.
********************************************************/

using System;
using System.Text;
using System.IO;
using BCL;


namespace Examples
{
    public class TestIntroDelivery
    {
        const int NSupp = 10;                  /* Number of suppliers */
        const int NCust = 7;                   /* Number of customers */
        const int MaxArcs = 100;               /* Max. num. of non-zero cost values */

        //Define XPRBDATAPATH to wherever you have placed the data folder; here we expect it to be same directory as compiled example.
        static string XPRBDATAPATH = Directory.GetParent(System.Reflection.Assembly.GetExecutingAssembly().Location).FullName + "/Data";
        static string VANFILE = XPRBDATAPATH + "/delivery/ifvan.dat";   /* Van data file */
        static string COSTFILE = XPRBDATAPATH + "/delivery/cost.dat";    /* Cost data file */

        /****DATA****/
        /* Supplier:      London  Luton  B'ham Bristl  Derby Stckpt   York */
        double[] SUPPLY = {140.0, 600.0,  50.0,  10.0, 400.0, 200.0,  20.0,
        /* Supplier: Derby  Soton Scnthp */
        90.0,  30.0,  12.0};
        /* Customer:      London Livpol Doncst   York   Hull Manchr Shffld */
        double[] DEMAND = {123.3,  56.4,  17.1, 192.8, 310.0,  47.0,  86.0};

        double[,] COST = new double[NSupp,NCust];        /* Cost per supplier-customer pair */

        double[,] IFVAN = new double[NSupp,NCust];       /* Non-zero if route uses vans instead
        of lorries */
        double VANCAP=40.0;               /* Capacity on routes that use vans */

        XPRBprob p = new XPRBprob("Delivery");           /* Initialize a new problem in BCL */

        /***********************************************************************/

        void modDelivery()
        {
            XPRBexpr lobj, lc;
            int s,c;
            XPRBvar[,] x = new XPRBvar[NSupp,NCust];

            /****VARIABLES****/
            for(s=0;s<NSupp;s++)
            for(c=0; c<NCust; c++)
                x[s,c] = p.newVar("x_s" + s);

            /****OBJECTIVE****/
        lobj = new XPRBexpr();
            for(s=0;s<NSupp;s++)             /* Objective: Minimize total cost */
                for(c=0; c<NCust; c++)
                lobj += COST[s,c]*x[s,c];
            p.setObj(p.newCtr("OBJ", lobj)); /* Set objective function */

            /****CONSTRAINTS****/
            for(c=0; c<NCust; c++)           /* Satisfy demand of each customer */
            {
                lc = new XPRBexpr(0);
                for(s=0;s<NSupp;s++)  lc += x[s,c];
                p.newCtr("Demand", lc >= DEMAND[c]);
            }

            for(s=0;s<NSupp;s++)             /* Keep within supply at each supplier*/
            {
                lc = new XPRBexpr(0);
                for(c=0; c<NCust; c++)  lc+= x[s,c];
                p.newCtr("Supply", lc <= SUPPLY[s]);
            }

            /****BOUNDS****/
            for(s=0;s<NSupp;s++)
                for(c=0; c<NCust; c++)
                    if(IFVAN[s,c]!=0) x[s,c].setUB(VANCAP);

            /****SOLVING + OUTPUT****/
            p.exportProb(BCLconstant.XPRB_MPS,"delivery");   /* Write out an MPS file */

            p.setSense(BCLconstant.XPRB_MINIM);           /* Set objective sense to minimization */
            p.lpOptimize();                      /* Solve the LP-problem */
            System.Console.WriteLine("Objective: " + p.getObjVal());  /* Get objective value */

            for(s=0;s<NSupp;s++)              /* Print out the solution values */
                for(c=0; c<NCust; c++)
                    System.Console.Write(x[s,c].getName() + ":" + x[s,c].getSol() + " ");
            System.Console.WriteLine();
        }

        /***********************************************************************/

        /**** Read data from files ****/
        void readData()
        {
            int s,c;
            double[] outdata;
            FileStream file;
            StreamReader fileStreamIn;

            /* Initialize data tables to 0: in the van data file some entries that are
            * zero are simply left out, but the function XPRBreadarrline only initializes
            * those elements to 0 that have been read, e.g. a data line ",,," results
            * in the first 4 elements of the array to be set to zero, even if the
            * maximum number of elements to be read (=last parameter of XPRBreadarrline)
            * has a much larger value */
            for(s=0;s<NSupp;s++)
                for(c=0; c<NCust; c++)
                {
                    COST[s,c] = 0;
                    IFVAN[s,c] = 0;
                }

            /* Read the demand data file */
            file = new FileStream(COSTFILE, FileMode.Open, FileAccess.Read);
            fileStreamIn = new StreamReader(file);
            for (s = 0; s < NSupp; s++)
            {
                p.XPRBreadarrline(fileStreamIn, 99, "{g}, ", out outdata, NCust);
                for (int i = 0; i < NCust; i++)
                    COST[s, i] = outdata[i];
            }
            fileStreamIn.Close();
            file.Close();

            /* Read the van data file */
            file = new FileStream(VANFILE, FileMode.Open, FileAccess.Read);
            fileStreamIn = new StreamReader(file);
            for (s = 0; s < NSupp; s++)
            {
                p.XPRBreadarrline(fileStreamIn, 99, "{g}, ", out outdata, NCust);
                for (int i = 0; i < NCust; i++)
                    IFVAN[s, i] = outdata[i];
            }
            fileStreamIn.Close();
            file.Close();

        }

        /***********************************************************************/

        public static void Main()
        {
            XPRB.init();

            TestIntroDelivery TestInstance = new TestIntroDelivery();

            TestInstance.readData();            /* Data input from file */
            TestInstance.modDelivery();         /* Problem formulation and solution */

            return;
        }

    }

}