InstanceFeasibilityAnalyzer.cs

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using LotSizingDataModel.Instance;
using LotSizingDataModel.Solver.Formulation;
using LotSizingDataModel.Solver.Modeling;
 
namespace LotSizingDataModel.Solver.Feasibility;
 
/// <summary>
/// Pre-solve instance feasibility facade. It never reports
/// Feasible: only proven Infeasible or Unknown.
/// </summary>
public sealed class InstanceFeasibilityAnalyzer
{
    private readonly MathematicalModelIntrinsicFeasibilityAnalyzer
        _modelAnalyzer = new();
 
    public IntrinsicFeasibilityAnalysisResult AnalyzeModel(
        MathematicalModel model,
        double tolerance = 1.0e-9)
    {
        return _modelAnalyzer.Analyze(
            model,
            tolerance);
    }
 
    public async ValueTask<IntrinsicFeasibilityAnalysisResult>
        AnalyzeAsync(
            LotSizingInstance instance,
            IMathematicalModelFormulation formulation,
            CancellationToken cancellationToken = default)
    {
        ArgumentNullException.ThrowIfNull(instance);
        ArgumentNullException.ThrowIfNull(formulation);
 
        MathematicalModel model =
            await formulation.BuildAsync(
                instance,
                cancellationToken);
 
        if (instance.HasClosedLoopReturnStreams)
        {
            instance.EnsureClosedLoopValid();
 
            model =
                new ClosedLoopSupplyNetworkModelDecorator()
                    .Apply(
                        instance,
                        model);
        }
 
        return _modelAnalyzer.Analyze(
            model);
    }
 
    public ValueTask<IntrinsicFeasibilityAnalysisResult>
        AnalyzeStandardAsync(
            LotSizingInstance instance,
            CancellationToken cancellationToken = default)
    {
        return AnalyzeAsync(
            instance,
            StandardLotSizingFormulationFactory.CreateDefault(),
            cancellationToken);
    }
}