/******************************************************** Xpress-BCL Java Example Problems ================================ file xbdlvriis.java ``````````````````` Transportation problem (infeasible data). Retrieving and printing IIS. (c) 2008 Fair Isaac Corporation author: S.Heipcke, 2005, rev. Mar. 2011 ********************************************************/ import java.io.*; import java.util.*; import com.dashoptimization.*; public class xbdlvriis { static final int NSupp = 10; /* Number of suppliers */ static final int NCust = 7; /* Number of customers */ static final int MaxArcs = 100; /* Max. num. of non-zero cost values */ static final String VANFILE = System.getProperty("XPRBDATA") + "/delivery/ifvan.dat"; static final String COSTFILE = System.getProperty("XPRBDATA") + "/delivery/cost.dat"; /****DATA****/ /* Supplier: London Luton B'ham Bristl Derby Stckpt */ static final double SUPPLY[] = {140.0, 200.0, 50.0, 10.0, 400.0, 200.0, /* Supplier: York Derby Soton Scnthp */ 20.0, 90.0, 30.0, 12}; /* Customer: London Livpol Doncst York Hull Manchr */ static final double DEMAND[] = {1230.3, 560.4, 117.1, 592.8, 310.0, 1247.0, /* Customer: Shffld */ 86}; static double[][] COST; /* Cost per supplier-customer pair */ static double[][] IFVAN; /* Non-zero if route uses vans instead of lorries */ static final double VANCAP=40; /* Capacity on routes that use vans */ static XPRB bcl; static XPRBprob p; /***********************************************************************/ static void modDelivery() { XPRBexpr lobj, lc; int s,c,i; XPRBvar[][] x; ArrayList iisctr,iisvar; int numv, numc, numiis, ct; bcl = new XPRB(); /* Initialize BCL */ p = bcl.newProb("Delivery"); /* Create a new problem in BCL */ /****VARIABLES****/ x = new XPRBvar[NSupp][NCust]; for(s=0;s<NSupp;s++) for(c=0; x[s][c]=p.newVar("x_s" lobj=new for(s=0;s<NSupp;s++) Objective: Minimize total cost Set objective function Satisfy demand of each customer lc=new Keep within supply at if(IFVAN[s][c]!=0) sense to minimization Solve the LP-problem status:=" + p.getLPStat());
  if (p.getLPStat()==XPRB.LP_OPTIMAL)
   System.out.println(" Number IIS:=" + numiis); 

   iisvar = new ArrayList();
   iisctr = new ArrayList();

   for(s=1;s<=numiis;s++)
   { 
    p.getIIS(iisvar, iisctr, s);
    numv = iisvar.size(); numc = iisctr.size();
    System.out.println(" IIS=" + s + " :=" + numv + " variables,=" +
                       numc + " if>0)
    {                              /* Print all variables in the IIS */
     System.out.print("        Variables: ");
     for(i=0;i<numv;i++) +=" " if>0)
    {                              /* Print all constraints in the IIS */
     System.out.print("        Constraints: ");
     for(i=0;i<numc;i++) +=" " Alternative way of enumerating IIS: numv=iisvar.size(); numc=iisctr.size(); approximation:=" + numv + " variables,=" + numc + " constraints with non-zero reduced ct=0;>0)
  {
   if(ct>0)
    System.out.println("IIS " + ct + ":  " + numv + " variables, " + numc + " constraints");
   ct++;  
   p.getIIS(iisvar, iisctr, ct);
   numv = iisvar.size(); numc = iisctr.size();
  }
   
/* Retrieve variables only */
   System.out.println("Variables");
   for(s=1;s<=numiis;s++)
   { 
    p.getIIS(iisvar, null, s);
    numv = iisvar.size(); 
    System.out.print("  IIS " + s + ":  " + numv + " variables  ( " );
    for(i=0;i<numv;i++) 
     System.out.print(((XPRBvar)iisvar.get(i)).getName() + " ");
     System.out.println(")");
   }

/* Retrieve constraints only */    
   System.out.println("Constraints");
   for(s=1;s<=numiis;s++)
   { 
    p.getIIS(null, iisctr, s);
    numc = iisctr.size();
    System.out.print("  IIS " + s + ":  " + numc + " constraints  ( ");
    for(i=0;i<numc;i++) 
     System.out.print(((XPRBctr)iisctr.get(i)).getName() + " ");
    System.out.println(")");
   } 
     
  }
 }

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

    /**** 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 multi line data file ****/
 static void readMultiLineFile(String filename, double[][] data) throws IOException
 {
  FileReader datafile=null;
  StreamTokenizer st;
  int i=0, j=0;

  datafile = new FileReader(filename);
  st = initST(datafile);
  do
  {
   do
   { 
    st.nextToken();
   } while(st.ttype==st.TT_EOL);    /* Skip empty lines */
   while(st.ttype == st.TT_NUMBER)
   {
    data[j][i++] = st.nval;
    if(st.nextToken() != ',') { j++; i=0; break;}
    st.nextToken();
   }
  } while( st.ttype == st.TT_EOL );
  datafile.close(); 
 }

    /**** Read data from files ****/
 static void readData() throws IOException
 {
  int s,c;  

  COST = new double[NSupp][NCust];
  IFVAN = new double[NSupp][NCust];
 
/* Initialize data tables to 0: in the van data file some entries that are 
 * zero are simply left out (that is, the lines are incomplete) */
  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 */
 readMultiLineFile(COSTFILE,COST);

        /* Read the van data file */
 readMultiLineFile(VANFILE,IFVAN);
}

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

 public static void main(String[] args)
 {
  try
  {
   readData();           /* Data input from file */
  }
  catch(IOException e)
  {
   System.err.println(e.getMessage());
   System.exit(1);
  }
  modDelivery();         /* Problem formulation and solution */
 }
}