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Folio - Examples from 'Getting Started' Description Different versions of a portfolio optimization problem. Basic modelling and solving tasks:
Source Files By clicking on a file name, a preview is opened at the bottom of this page. Data Files folioinit.cs /******************************************************** Xpress-BCL C# Example Problems ============================== file folioinit.cs ````````````````` Modeling a small LP problem to perform portfolio optimization. Explicit initialization. (c) 2008-2024 Fair Isaac Corporation authors: S.Heipcke, D.Brett. ********************************************************/ using System; using System.Text; using System.IO; using BCL; namespace Examples { public class TestUGFolioInit { const int NSHARES = 10; // Number of shares const int NRISK = 5; // Number of high-risk shares const int NNA = 4; // Number of North-American shares double[] RET = {5,17,26,12,8,9,7,6,31,21}; // Estimated return in investment int[] RISK = {1,2,3,8,9}; // High-risk values among shares int[] NA = {0,1,2,3}; // Shares issued in N.-America public void solveProb() { XPRB.init(); int s; XPRBprob p = new XPRBprob("FolioLP"); // Initialize a new problem in BCL XPRBexpr Risk,Na,Return,Cap; XPRBvar[] frac = new XPRBvar[NSHARES]; // Fraction of capital used per share // Create the decision variables for(s=0;s<NSHARES;s++) frac[s] = p.newVar("frac"); // Objective: total return Return = new XPRBexpr(); for(s=0;s<NSHARES;s++) Return += RET[s]*frac[s]; p.setObj(p.newCtr("Objective", Return)); // Set the objective function // Limit the percentage of high-risk values Risk = new XPRBexpr(); for(s=0;s<NRISK;s++) Risk += frac[RISK[s]]; p.newCtr("Risk", Risk <= 1.0/3); // Minimum amount of North-American values Na = new XPRBexpr(); for(s=0;s<NNA;s++) Na += frac[NA[s]]; p.newCtr("NA", Na >= 0.5); // Spend all the capital Cap = new XPRBexpr(); for(s=0;s<NSHARES;s++) Cap += frac[s]; p.newCtr("Cap", Cap == 1); // Upper bounds on the investment per share for(s=0;s<NSHARES;s++) frac[s].setUB(0.3); // Solve the problem p.setSense(BCLconstant.XPRB_MAXIM); p.lpOptimize(); /* Solve the LP-problem */ string[] LPSTATUS = {"not loaded", "optimal", "infeasible", "worse than cutoff", "unfinished", "unbounded", "cutoff in dual"}; System.Console.WriteLine("Problem status: " + LPSTATUS[p.getLPStat()]); // Solution printing System.Console.WriteLine("Total return: " + p.getObjVal()); for(s=0;s<NSHARES;s++) System.Console.WriteLine(s + ": " + frac[s].getSol()*100 + "%"); } public static void Main() { TestUGFolioInit TestInstance = new TestUGFolioInit(); if(XPRB.init() != 0) { System.Console.WriteLine("Initialization failed."); return; } TestInstance.solveProb(); return; } } } | |||||||||
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