/********************************************************
 * Xpress-BCL Java Example Problems
 * ================================
 *
 * file xbexpl2.java
 * `````````````````
 * Transportation model demonstrating use of index sets.
 *
 * (c) 2008-2024 Fair Isaac Corporation
 * author: S.Heipcke, Jan. 2000, rev. Dec. 2011
 ********************************************************/

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

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; a++) x[a] = p.newVar("x");

    /****OBJECTIVE****/
    lobj = new XPRBexpr();
    for (a = 0; a < NArc; a++) lobj.add(x[a].mul(COST[a].value));
    p.setObj(lobj); /* Set objective function */

    /****CONSTRAINTS****/
    /**** Create all constraints in a single loop ****/
    /* Initialize the linear expressions */
    av = new XPRBexpr[NSuppl];
    for (s = 0; s < NSuppl; s++) av[s] = new XPRBexpr();
    de = new XPRBexpr[NCustom];
    for (c = 0; c < NCustom; c++) de[c] = new XPRBexpr();

    for (a = 0; a < NArc; a++) {
        /* Add terms to expressions one-by-one */
      av[COST[a].suppl].add(x[a]);
      de[COST[a].custm].add(x[a]);
    }
    /* Terminate the constraint definition */
    for (s = 0; s < NSuppl; s++) p.newCtr("Avail", av[s].lEql(AVAIL[s]));
    for (c = 0; c < NCustom; c++) p.newCtr("Demand", de[c].gEql(DEMAND[c]));

    /****SOLVING + OUTPUT****/
    p.exportProb(XPRB.MPS, "trans"); /* Matrix generation & output to MPS file */

    p.lpOptimize(""); /* Solve the LP-problem */
    System.out.println("Objective: " + p.getObjVal()); /* Get objective value */

    for (a = 0; a < NArc; a++) /* Print out the solution values */
      if (x[a].getSol() > 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 */
        XPRBexprContext context =
            new XPRBexprContext() /* Release XPRBexpr instances at end of block. */) {
      readData(p); /* Data input from file */
      modTrans(p); /* Formulate and solve the problem */
    } catch (IOException e) {
      System.err.println(e.getMessage());
      System.exit(1);
    }
  }
}