/******************************************************** Xpress-BCL Java Example Problems ================================ file xbburgl.java ````````````````` Burglar problem. Binary variable formulation with index sets. -- Formulating logical conditions with indicator constraints -- (c) 2009 Fair Isaac Corporation author: S.Heipcke, June 2009, rev. Mar. 2011 ********************************************************/ import com.dashoptimization.*; public class xbburgl { /****DATA****/ /* Item: ca ne va pi tv vi ch br */ static final double[] VALUE = {15,100, 90, 60, 40, 15, 10, 1}; /* Value of items */ static final double[] WEIGHT = { 2, 20, 20, 30, 40, 30, 60, 10}; /* Weight of items */ static final double WTMAX = 102; /* Max weight allowed for haul */ static final String[] ITEMNAMES = {"camera", "necklace", "vase", "picture", "tv", "video", "chest", "brick"}; static int NItems; /* Number of items */ public static void main(String[] args) { XPRB bcl; XPRBvar[] x; XPRBindexSet ITEMS; /* Set of items */ int i; XPRBexpr lobj, kn; XPRBctr Log3a,Log3b; XPRBprob p; bcl = new XPRB(); /* Initialize BCL */ p = bcl.newProb("BurglarL"); /* Create a new problem in BCL */ /****INDICES****/ ITEMS=p.newIndexSet("Items",ITEMNAMES.length); /* Create the index set */ for(i=0;i<ITEMNAMES.length;i++) NItems=ITEMS.getSize(); Get the size of index set x=new for(i=0;i<NItems;i++) x[i]=p.newVar("x_"+ITEMS.getIndexName(i), if we take item otherwise lobj=new Set objective: maximize total value kn=new Weight restriction Logic constraint: Either and="picture" or="tv" not both Values within each pair are same x["vase"]== x["tv"]== Choose exactly one Log3a=p.newCtr("Log3a", <=0 Log3b=p.newCtr("Log3b",>= 2 */

/* Turn the 2 constraints into indicator constraints */
 Log3a.setIndicator(1, x[ITEMS.getIndex("vase")]);
                                  /* x["vase"]=1 -> x["tv"]+x["video"]=0 */
 Log3b.setIndicator(-1, x[ITEMS.getIndex("vase")]);
                                  /* x["vase"]=0 -> x["tv"]+x["video"]=2 */

/* Alternative MIP formulation (instead of Log3a and Log3b) */
/*
 p.newCtr("Log3", 
   x[ITEMS.getIndex("tv")].add(x[ITEMS.getIndex("vase")]).eql(1) );
*/                                            /* x["tv"] = 1 - x["vase"] */
 

/****SOLVING + OUTPUT****/
  p.setSense(XPRB.MAXIM);            /* Choose the sense of the optimization */
  p.mipOptimize("");                 /* Solve the MIP-problem */
  System.out.println("Objective: " + p.getObjVal());  /* Get objective value */

  for(i=0;i<NItems;i++) Print out the chosen items>0) 
    System.out.println(ITEMS.getIndexName(i) + ": " + x[i].getSol());
 }
}