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

  file foliolp.java
  `````````````````
  Modeling a small LP problem 
  to perform portfolio optimization.

  (c) 2008 Fair Isaac Corporation
      author: S.Heipcke, 2003, rev. Dec. 2011
********************************************************/

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

public class foliolp
{
 static final int NSHARES = 10;     /* Number of shares */
 static final int NRISK = 5;        /* Number of high-risk shares */
 static final int NNA = 4;          /* Number of North-American shares */

 static final double[] RET = {5,17,26,12,8,9,7,6,31,21};
                                    /* Estimated return in investment  */
 static final int[] RISK = {1,2,3,8,9};  /* High-risk values among shares */
 static final int[] NA = {0,1,2,3};      /* Shares issued in N.-America */

 static final String[] LPSTATUS = {"not loaded", "optimal", "infeasible", 
          "worse than cutoff", "unfinished", "unbounded", "cutoff in dual",
	  "unsolved", "nonconvex"};

 public static void main(String[] args)
 { 
  int s;
  XPRB bcl;
  XPRBprob p;
  XPRBexpr Risk,Na,Return,Cap;
  XPRBvar[] frac;                    /* Fraction of capital used per share */

  bcl = new XPRB();                  /* Initialize BCL */
  p = bcl.newProb("FolioLP");        /* Create a new problem in BCL */

/* Create the decision variables */
  frac = new XPRBvar[NSHARES];
  for(s=0;s<NSHARES;s++) frac[s] = p.newVar("frac");  /*, XPRB.PL, 0, 0.3); */
 
/* Objective: total return */
  Return = new XPRBexpr();
  for(s=0;s<NSHARES;s++) Return.add(frac[s].mul(RET[s])); 
  p.setObj(Return);                  /* Set the objective function */

/* Limit the percentage of high-risk values */
  Risk = new XPRBexpr();
  for(s=0;s<NRISK;s++) Risk.add(frac[RISK[s]]); 
  p.newCtr("Risk", Risk.lEql(1.0/3) );

/* Equivalent:
  XPRBctr CRisk;
  CRisk = p.newCtr("Risk");
  for(s=0;s<NRISK;s++) CRisk.addTerm(frac[RISK[s]], 1);
  CRisk.setType(XPRB.L);
  CRisk.addTerm(1.0/3);
*/

/* Minimum amount of North-American values */
  Na = new XPRBexpr();
  for(s=0;s<NNA;s++) Na.add(frac[NA[s]]); 
  p.newCtr("NA", Na.gEql(0.5) );

/* Spend all the capital */
  Cap = new XPRBexpr();
  for(s=0;s<NSHARES;s++) Cap.add(frac[s]); 
  p.newCtr("Cap", Cap.eql(1));

/* Upper bounds on the investment per share */
  for(s=0;s<NSHARES;s++) frac[s].setUB(0.3);

/* Export matrix to a file */
  try
  {
   p.exportProb(XPRB.MPS, "Folio");
   p.setSense(XPRB.MAXIM);
   p.exportProb(XPRB.LP, "Folio");
  }
  catch(IOException e)
  {
   System.err.println(e.getMessage());
   System.exit(1);
  }

/* Disable all BCL and Optimizer message printing, except error messages */
/*  p.setMsgLevel(1); */

/* Solve the problem */
  p.setSense(XPRB.MAXIM);
  p.lpOptimize("");
 
  System.out.println("Problem status: " + LPSTATUS[p.getLPStat()]);
 
/* Solution printing */
  System.out.println("Total return: " + p.getObjVal());
  for(s=0;s<NSHARES;s++) 
   System.out.println(s + ": " + frac[s].getSol()*100 + "%");  

/* Delete the problem */
  p.finalize();              
  p=null;
 }
}