Mip1.java
/* Copyright 2019, Gurobi Optimization, LLC */ /* This example formulates and solves the following simple MIP model: maximize x + y + 2 z subject to x + 2 y + 3 z <= 4 x + y >= 1 x, y, z binary */ import gurobi.*; public class Mip1 { public static void main(String[] args) { try { // Create empty environment, set options, and start GRBEnv env = new GRBEnv(true); env.set("logFile", "mip1.log"); env.start(); // Create empty model GRBModel model = new GRBModel(env); // Create variables GRBVar x = model.addVar(0.0, 1.0, 0.0, GRB.BINARY, "x"); GRBVar y = model.addVar(0.0, 1.0, 0.0, GRB.BINARY, "y"); GRBVar z = model.addVar(0.0, 1.0, 0.0, GRB.BINARY, "z"); // Set objective: maximize x + y + 2 z GRBLinExpr expr = new GRBLinExpr(); expr.addTerm(1.0, x); expr.addTerm(1.0, y); expr.addTerm(2.0, z); model.setObjective(expr, GRB.MAXIMIZE); // Add constraint: x + 2 y + 3 z <= 4 expr = new GRBLinExpr(); expr.addTerm(1.0, x); expr.addTerm(2.0, y); expr.addTerm(3.0, z); model.addConstr(expr, GRB.LESS_EQUAL, 4.0, "c0"); // Add constraint: x + y >= 1 expr = new GRBLinExpr(); expr.addTerm(1.0, x); expr.addTerm(1.0, y); model.addConstr(expr, GRB.GREATER_EQUAL, 1.0, "c1"); // Optimize model model.optimize(); System.out.println(x.get(GRB.StringAttr.VarName) + " " +x.get(GRB.DoubleAttr.X)); System.out.println(y.get(GRB.StringAttr.VarName) + " " +y.get(GRB.DoubleAttr.X)); System.out.println(z.get(GRB.StringAttr.VarName) + " " +z.get(GRB.DoubleAttr.X)); System.out.println("Obj: " + model.get(GRB.DoubleAttr.ObjVal)); // Dispose of model and environment model.dispose(); env.dispose(); } catch (GRBException e) { System.out.println("Error code: " + e.getErrorCode() + ". " + e.getMessage()); } } }
