Try our new documentation site.


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());
    }
  }
}

Try Gurobi for Free

Choose the evaluation license that fits you best, and start working with our Expert Team for technical guidance and support.

Evaluation License
Get a free, full-featured license of the Gurobi Optimizer to experience the performance, support, benchmarking and tuning services we provide as part of our product offering.
Academic License
Gurobi supports the teaching and use of optimization within academic institutions. We offer free, full-featured copies of Gurobi for use in class, and for research.
Cloud Trial

Request free trial hours, so you can see how quickly and easily a model can be solved on the cloud.

Search