Try our new documentation site (beta).


bilinear_vb.vb


' Copyright 2024, Gurobi Optimization, LLC */

' This example formulates and solves the following simple bilinear model:
'
'     maximize    x
'     subject to  x + y + z <= 10
'                 x * y <= 2          (bilinear inequality)
'                 x * z + y * z == 1  (bilinear equality)
'                 x, y, z non-negative (x integral in second version)

Imports Gurobi

Class bilinear_vb
    Shared Sub Main()
        Try
            Dim env As New GRBEnv("bilinear.log")
            Dim model As New GRBModel(env)

            ' Create variables

            Dim x As GRBVar = model.AddVar(0, GRB.INFINITY, 0, GRB.CONTINUOUS, "x")
            Dim y As GRBVar = model.AddVar(0, GRB.INFINITY, 0, GRB.CONTINUOUS, "y")
            Dim z As GRBVar = model.AddVar(0, GRB.INFINITY, 0, GRB.CONTINUOUS, "z")

            ' Set objective
            Dim obj As GRBLinExpr = x
            model.SetObjective(obj, GRB.MAXIMIZE)

            ' Add linear constraint: x + y + z <= 10

            model.AddConstr(x + y + z <= 10, "c0")

            ' Add bilinear inequality: x * y <= 2

            model.AddQConstr(x * y <= 2, "bilinear0")

            ' Add bilinear equality: x * z + y * z == 1

            model.AddQConstr(x * z + y * z = 1, "bilinear1")

            ' Optimize model

            model.Optimize()

            Console.WriteLine(x.VarName & " " & x.X)
            Console.WriteLine(y.VarName & " " & y.X)
            Console.WriteLine(z.VarName & " " & z.X)

            Console.WriteLine("Obj: " & model.ObjVal & " " & obj.Value)

            x.Set(GRB.CharAttr.VType, GRB.INTEGER)
            model.Optimize()

            Console.WriteLine(x.VarName & " " & x.X)
            Console.WriteLine(y.VarName & " " & y.X)
            Console.WriteLine(z.VarName & " " & z.X)

            Console.WriteLine("Obj: " & model.ObjVal & " " & obj.Value)

            ' Dispose of model and env

            model.Dispose()

            env.Dispose()
        Catch e As GRBException
            Console.WriteLine("Error code: " & e.ErrorCode & ". " & e.Message)
        End Try

    End Sub
End Class

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

Gurobi Optimization