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### Mip1.java

/* Copyright 2016, Gurobi Optimization, Inc. */

/* 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 {
GRBEnv    env   = new GRBEnv("mip1.log");
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();
model.setObjective(expr, GRB.MAXIMIZE);

// Add constraint: x + 2 y + 3 z <= 4

expr = new GRBLinExpr();

// Add constraint: x + y >= 1

expr = new GRBLinExpr();

// 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());
}
}
}