/********************************************************
  Xpress-BCL Java Example Problems
  ================================

  file xbexpl2.java
  `````````````````
  Transportation model demonstrating use of index sets.

  (c) 2008-2023 Fair Isaac Corporation
      author: S.Heipcke, Jan. 2000, rev. Dec. 2011
********************************************************/

import java.io.*;
import com.dashoptimization.*;

public class xbexpl2 {
    static final int MaxSuppliers = 100; /* Max. number of suppliers */
    static final int MaxCustomers = 1000;/* Max. number of customers */
    static final int MaxArcs = 10000;    /* Max. number of non-zero cost values */
    static final String DEMANDFILE = System.getProperty("XPRBDATA") +
        "/trans/ex2dem1.dat";
    /* Demand data file (comma-separated format) */
    static final String AVAILFILE = System.getProperty("XPRBDATA") +
        "/trans/ex2avail.dat";
    /* Supply data file (comma-separated format) */
    static final String COSTFILE = System.getProperty("XPRBDATA") +
        "/trans/ex2cost.dat";
    /* Cost data file (comma-separated format) */

    static XPRBindexSet Suppliers; /* Set of suppliers */
    static XPRBindexSet Customers; /* Set of customers */
    static double[] AVAIL;         /* Availability of products */
    static double[] DEMAND;        /* Demand by customers */

    static class TData {
        int suppl;
        int custm;
        double value;
    };

    static TData[] COST = new TData[MaxArcs]; /* Cost per supplier-customer pair*/

    static int NSuppl=0, NCustom=0, NArc=0;   /* Actual numbers of suppliers,
                                                 customers, and arcs */

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

    static void modTrans(XPRBprob p) throws IOException {
        XPRBexpr lobj, av[], de[];
        int s,c,a;
        XPRBvar[] x;

        /****VARIABLES****/
        x = new XPRBvar[NArc];
        for(a=0; a<NArc; x[a]=p.newVar("x"); lobj=new for(a=0; Set objective function Create all constraints in a single loop Initialize the linear expressions av=new for(s=0; av[s]=new de=new for(c=0; de[c]=new Add terms to one-by-one Terminate constraint definition Matrix generation output MPS file Solve LP-problem>0)
                System.out.println(Suppliers.getIndexName(COST[a].suppl) + " (" +
                                   AVAIL[COST[a].suppl] + ") -> " + Customers.getIndexName(COST[a].custm)
                                   + " (" + DEMAND[COST[a].custm] + "): " + x[a].getSol());
    }

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

    /**** Initialize the stream tokenizer ****/
    static StreamTokenizer initST(FileReader file) {
        StreamTokenizer st=null;

        st= new StreamTokenizer(file);   /* Initialize the stream tokenizer */
        st.commentChar('!');             /* Use the character '!' for comments */
        st.eolIsSignificant(true);       /* Return end-of-line character */
        st.ordinaryChar(',');            /* Use ',' as separator */
        st.parseNumbers();               /* Read numbers as numbers (not strings)*/
        return st;
    }

    /**** Read data from files ****/
    static void readData(XPRBprob p) throws IOException {
        FileReader datafile=null;
        StreamTokenizer st;
        int i;

        /* Create supplier and customer index sets */
        Suppliers = p.newIndexSet("suppl", MaxSuppliers);
        Customers = p.newIndexSet("custom", MaxCustomers);
        AVAIL = new double[MaxSuppliers];
        DEMAND = new double[MaxCustomers];

        /* Read the demand data file */
        datafile = new FileReader(DEMANDFILE);
        st = initST(datafile);
        do {
            do {
                st.nextToken();
            } while(st.ttype==st.TT_EOL);    /* Skip empty lines */
            if(st.ttype != st.TT_WORD) break;
            i=Customers.addElement(st.sval);
            if(st.nextToken() != ',') break;
            if(st.nextToken() != st.TT_NUMBER) break;
            DEMAND[i] = st.nval;
        } while( st.nextToken() == st.TT_EOL );
        datafile.close();
        NCustom = Customers.getSize();

        /* Read the supply data file */
        datafile = new FileReader(AVAILFILE);
        st = initST(datafile);
        do {
            do {
                st.nextToken();
            } while(st.ttype==st.TT_EOL);
            if(st.ttype != st.TT_WORD) break;
            i=Suppliers.addElement(st.sval);
            if(st.nextToken() != ',') break;
            if(st.nextToken() != st.TT_NUMBER) break;
            AVAIL[i] = st.nval;
        } while( st.nextToken() == st.TT_EOL );
        datafile.close();
        NSuppl = Suppliers.getSize();

        /* Read the cost data file */
        NArc = 0;
        datafile = new FileReader(COSTFILE);
        st = initST(datafile);
        do {                      /* Read the cost data file and fill the index sets */
            do {
                st.nextToken();
            } while(st.ttype==st.TT_EOL);    /* Skip empty lines */
            if(st.ttype != st.TT_WORD) break;
            COST[NArc]=new TData();
            COST[NArc].suppl=Suppliers.getIndex(st.sval);
            if(COST[NArc].suppl<0) System.out.println("Supp(" + st.sval + ")");
            if(st.nextToken() != ',') break;
            if(st.nextToken() != st.TT_WORD) break;
            COST[NArc].custm=Customers.getIndex(st.sval);
            if(COST[NArc].custm<0) System.out.println("Cust(" + st.sval + ")");
            if(st.nextToken() != ',') break;
            if(st.nextToken() != st.TT_NUMBER) break;
            COST[NArc++].value = st.nval;
        } while( st.nextToken() == st.TT_EOL );
        datafile.close();

        System.out.println("C: " + NCustom + "  S: " + NSuppl + "  A: " + NArc);
    }

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

    public static void main(String[] args) {
        try (XPRBprob p = new XPRBprob("Trans")) { /* Initialize BCL create a new problem */
            readData(p);                     /* Data input from file */
            modTrans(p);                     /* Formulate and solve the problem */
        }
        catch(IOException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }
}