Cplex 12.7 GetValue() problem

[Ali Pala]

Hi,

When using Cplex 12.7, we obtain the optimal solution on our Solution object, but get the below error message. Same model works with Gurobi with no issues. Therefore, it looks like the problem is related to Cplex 12.7.

at ILOG.CPLEX.Cplex.GetValues(INumVar[] var, Int32 start, Int32 num)

at ILOG.CPLEX.Cplex.GetValues(INumVar[] var)

at OPTANO.Modeling.Optimization.Solver.Cplex127.CplexSolver.SolveAdapterSpecific(Int32 prioLevel, IDictionary`2 variableValues)

at OPTANO.Modeling.Optimization.SolverBase.CallSolveOnAdapter(Int32 prioLevel, Dictionary`2 variableValues, Boolean isResolve)

at OPTANO.Modeling.Optimization.SolverBase.BuildConfigureAndSolveOnAdapter(Int32 prioLevel, Dictionary`2 variableValues, Boolean isResolve, TimeSpan gloablElapsedTime)

at OPTANO.Modeling.Optimization.SolverBase.BuildConfigureAndSolveOnAdapter(Int32 prioLevel, Dictionary`2 variableValues, Boolean isResolve)

at OPTANO.Modeling.Optimization.SolverBase.SolveSingleStageModel(Dictionary`2 startSolution, Boolean isResolve, List`1 objectiveStages)

at OPTANO.Modeling.Optimization.SolverBase.SolveNonNative(Dictionary`2 variableValues, Boolean isResolve)

at OPTANO.Modeling.Optimization.SolverBase.Solve(Model model, Dictionary`2 variableValues)

 Any suggestions regarding that question?

[OPTANO Team]

Hi,

please find attached a mini demo using cplex 12.7 and retrieving the variable values.

Does this example run on your system?

Please copy the 3 cplex 12.7 files in the same folder.

Best

jp

[OPTANO Team]

Program.cs

// See https://aka.ms/new-console-template for more information

using OPTANO.Modeling.Common;
using OPTANO.Modeling.Optimization;
using OPTANO.Modeling.Optimization.Enums;

Console.WriteLine("Starting CPLEX Test");
var model = new Model();

var x = new Variable("x", 0, double.PositiveInfinity, VariableType.Integer);
var y = new Variable("y", 0, double.PositiveInfinity, VariableType.Integer);


model.AddObjective(new Objective(2 * x + y + 10, "goal", ObjectiveSense.Maximize), "goal");

model.AddConstraint(x + y <= 100);

var solver = new OPTANO.Modeling.Optimization.Solver.Cplex127.CplexSolver();
var solution = solver.Solve(model);
Console.WriteLine($"This is {solver}");
Console.WriteLine($"Finished with status {solution.Status}");

//solve retrieves values per default configuration automatically
Console.WriteLine($"Variable x is {x.Value}");
Console.WriteLine($"Variable y is {y.Value}");

trial.csproj

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net6.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <PlatformTarget>x64</PlatformTarget>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="optano.modeling" Version="3.10.0.538" />
  </ItemGroup>

  <ItemGroup>
    <Reference Include="ILOG.Concert">
      <HintPath>ILOG.Concert.dll</HintPath>
    </Reference>
    <Reference Include="ILOG.CPLEX">
      <HintPath>ILOG.CPLEX.dll</HintPath>
    </Reference>
  </ItemGroup>

  <ItemGroup>
    <None Update="cplex1270.dll">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
  </ItemGroup>

</Project>

[Ali Pala]

It worked out, thanks.

[OPTANO Team]

Perfect. Happy to help!

jp