/******************************************************** Xpress-BCL Java Example Problems ================================ file xbdlvriis2rep.java ``````````````````````` Transportation problem (infeasible data). Repairing infeasibility. - Using Optimizer functions - (c) 2008-2023 Fair Isaac Corporation author: S.Heipcke, Jan. 2008, rev. Mar. 2011 ********************************************************/ import java.io.*; import java.util.*; import java.text.DecimalFormat; import com.dashoptimization.*; public class xbdlvriis2rep { 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 XPRSprob op; /***********************************************************************/ static void modDelivery() { XPRBexpr lobj, lc; int s,c,i; XPRBvar[][] x; XPRBctr[] CSupply, CDemand; int nrow, ncol; IntHolder iscode; double[] lrp, grp, lbp, ubp; try (XPRBprob p = new XPRBprob("Delivery"); /* Initialize BCL and create a new problem */ XPRS xprs = new XPRS()) { /* Initialize Xpress-Optimizer */ /****VARIABLES****/ x = new XPRBvar[NSupp][NCust]; for(s=0;s<NSupp;s++) for(c=0; x[s][c]=p.newVar("x_s" s +="_" lobj=new for(s=0;s<NSupp;s++) Objective: Minimize total cost Set objective function CDemand=new Satisfy demand of each customer lc=new CDemand[c]=p.newCtr("Demand", CSupply=new Keep within supply at CSupply[s]=p.newCtr("Supply", if(IFVAN[s][c]!=0) sense to minimization Solve the LP-problem status:=" + p.getLPStat());
            if (p.getLPStat()==XPRB.LP_OPTIMAL)
                System.out.println(">= rows)
                  ax + aux_var  = b
                  ax + aux_var >= b
                  lbp:
                  x_i + aux_var >= l
                  ubp:
                  x_i - aux_var <= u
                */

                /**** Simplified infeasibility repair:
                      specifying preferences per constraint/bound type ****/

                System.out.println("\n**** Repair infeasibility:");
                iscode = new IntHolder();
                op.repairInfeas(iscode, 'c', 'o', ' ', 10, 9, 0, 20, 0,001);
                printSolution(p, iscode.value, x);

                /**** Weighted infeasibility repair:
                      specifying preferences for every constraint/bound separately ****/

                ncol=op.getIntAttrib(XPRS.ORIGINALCOLS);
                nrow=op.getIntAttrib(XPRS.ORIGINALROWS);
                lrp = new double[nrow];
                grp = new double[nrow];
                lbp = new double[ncol];
                ubp = new double[ncol];

                /* Relax bounds due to van capacity */
                /* Repairweightedinfeas for upper bounds of concerned flow variables */

                for(s=0; s<NSupp; for(c=0; if(IFVAN[s][c]!=0) ubp[x[s][c].getColNum()]=20; Relax van ubp,='d' 0.001,="" supply limits buy in additional Repairinfeas for='less or equal' side of Supply constraints for(s=0; lrp[CSupply[s].getRowNum()]=10; demand not satisfy all Demand grp[CDemand[c].getRowNum()]=9; Initialize the stream tokenizer static StreamTokenizer st=null; Use character='!' comments Return end-of-line as separator Read numbers return multi line data file void throws IOException FileReader datafile=null; int i=0, j=0; do while(st.ttype==st.TT_EOL); Skip empty lines data[j][i++]=st.nval; !=',' st.ttype== st.TT_EOL from files COST=new IFVAN=new tables to some entries that are zero simply left out COST[s][c]=0; IFVAN[s][c]=0; Print solution values double java.lang.String rstat[]={"relaxed optimum found",="relaxed problem infeasible" ,="relaxed problem unbounded">0,01)
                        System.out.print(x[s][c].getName()+ ":" + x[s][c].getSol() + " ");
            System.out.println();
            System.out.println("Violations:");
            for(c=0; c<NCust; sup=0; for(s=0; sup+=x[s][c].getSol(); Customer=" + c + " :>SUPPLY[s])
                    System.out.println("  Supplier " + s + ": " +  (dem-SUPPLY[s]) );
            }
            for(s=0; s<NSupp; for(c=0; if(IFVAN[s][c]!=0 Van=" + s + " c +=": " static void int double java.lang.String rstat[]={"relaxed optimum found",="relaxed problem infeasible" ,="relaxed problem unbounded">=0 && sol[x[s][c].getColNum()]>0,01)
                        System.out.print(x[s][c].getName()+ ":" + sol[x[s][c].getColNum()] + " ");
            System.out.println();
            System.out.println("Violations:");
            for(c=0; c<NCust; sup=0; for(s=0;>=0) sup+=sol[x[s][c].getColNum()];
                if(sup<DEMAND[c]) Customer=" + c + " :>=0) dem+=sol[x[s][c].getColNum()];
                if(dem>SUPPLY[s])
                    System.out.println("  Supplier " + s + ": " +  (dem-SUPPLY[s]) );
            }
            for(s=0; s<NSupp; for(c=0; if(IFVAN[s][c]!=0>=0 &&
                       VANCAP<sol[x[s][c].getColNum()])
                        System.out.println("  Van " + s + "-" + c + ": " + (sol[x[s][c].getColNum()]-VANCAP) );
        }
    }

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

    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 */
    }
}