public void TestCrossValidationMacroWithStratification()
        {
            var dataPath = GetDataPath(@"breast-cancer.txt");

            using (var env = new TlcEnvironment(42))
            {
                var subGraph = env.CreateExperiment();

                var nop       = new ML.Transforms.NoOperation();
                var nopOutput = subGraph.Add(nop);

                var learnerInput = new ML.Trainers.StochasticDualCoordinateAscentBinaryClassifier
                {
                    TrainingData = nopOutput.OutputData,
                    NumThreads   = 1
                };
                var learnerOutput = subGraph.Add(learnerInput);

                var modelCombine = new ML.Transforms.ManyHeterogeneousModelCombiner
                {
                    TransformModels = new ArrayVar <ITransformModel>(nopOutput.Model),
                    PredictorModel  = learnerOutput.PredictorModel
                };
                var modelCombineOutput = subGraph.Add(modelCombine);

                var experiment  = env.CreateExperiment();
                var importInput = new ML.Data.TextLoader(dataPath);
                importInput.Arguments.Column = new ML.Data.TextLoaderColumn[]
                {
                    new ML.Data.TextLoaderColumn {
                        Name = "Label", Source = new[] { new ML.Data.TextLoaderRange(0) }
                    },
                    new ML.Data.TextLoaderColumn {
                        Name = "Strat", Source = new[] { new ML.Data.TextLoaderRange(1) }
                    },
                    new ML.Data.TextLoaderColumn {
                        Name = "Features", Source = new[] { new ML.Data.TextLoaderRange(2, 9) }
                    }
                };
                var importOutput = experiment.Add(importInput);

                var crossValidate = new ML.Models.CrossValidator
                {
                    Data                 = importOutput.Data,
                    Nodes                = subGraph,
                    TransformModel       = null,
                    StratificationColumn = "Strat"
                };
                crossValidate.Inputs.Data            = nop.Data;
                crossValidate.Outputs.PredictorModel = modelCombineOutput.PredictorModel;
                var crossValidateOutput = experiment.Add(crossValidate);
                experiment.Compile();
                experiment.SetInput(importInput.InputFile, new SimpleFileHandle(env, dataPath, false, false));
                experiment.Run();
                var data = experiment.GetOutput(crossValidateOutput.OverallMetrics);

                var schema = data.Schema;
                var b      = schema.TryGetColumnIndex("AUC", out int metricCol);
                Assert.True(b);
                b = schema.TryGetColumnIndex("Fold Index", out int foldCol);
                Assert.True(b);
                using (var cursor = data.GetRowCursor(col => col == metricCol || col == foldCol))
                {
                    var    getter     = cursor.GetGetter <double>(metricCol);
                    var    foldGetter = cursor.GetGetter <DvText>(foldCol);
                    DvText fold       = default;

                    // Get the verage.
                    b = cursor.MoveNext();
                    Assert.True(b);
                    double avg = 0;
                    getter(ref avg);
                    foldGetter(ref fold);
                    Assert.True(fold.EqualsStr("Average"));

                    // Get the standard deviation.
                    b = cursor.MoveNext();
                    Assert.True(b);
                    double stdev = 0;
                    getter(ref stdev);
                    foldGetter(ref fold);
                    Assert.True(fold.EqualsStr("Standard Deviation"));
                    Assert.Equal(0.00485, stdev, 5);

                    double sum = 0;
                    double val = 0;
                    for (int f = 0; f < 2; f++)
                    {
                        b = cursor.MoveNext();
                        Assert.True(b);
                        getter(ref val);
                        foldGetter(ref fold);
                        sum += val;
                        Assert.True(fold.EqualsStr("Fold " + f));
                    }
                    Assert.Equal(avg, sum / 2);
                    b = cursor.MoveNext();
                    Assert.False(b);
                }
            }
        }
        public void TestSimpleTrainExperiment()
        {
            var dataPath = GetDataPath("adult.tiny.with-schema.txt");

            using (var env = new TlcEnvironment())
            {
                var experiment = env.CreateExperiment();

                var importInput  = new ML.Data.TextLoader(dataPath);
                var importOutput = experiment.Add(importInput);

                var catInput = new ML.Transforms.CategoricalOneHotVectorizer
                {
                    Data = importOutput.Data
                };
                catInput.AddColumn("Categories");
                var catOutput = experiment.Add(catInput);

                var concatInput = new ML.Transforms.ColumnConcatenator
                {
                    Data = catOutput.OutputData
                };
                concatInput.AddColumn("Features", "Categories", "NumericFeatures");
                var concatOutput = experiment.Add(concatInput);

                var sdcaInput = new ML.Trainers.StochasticDualCoordinateAscentBinaryClassifier
                {
                    TrainingData = concatOutput.OutputData,
                    LossFunction = new HingeLossSDCAClassificationLossFunction()
                    {
                        Margin = 1.1f
                    },
                    NumThreads = 1,
                    Shuffle    = false
                };
                var sdcaOutput = experiment.Add(sdcaInput);

                var scoreInput = new ML.Transforms.DatasetScorer
                {
                    Data           = concatOutput.OutputData,
                    PredictorModel = sdcaOutput.PredictorModel
                };
                var scoreOutput = experiment.Add(scoreInput);

                var evalInput = new ML.Models.BinaryClassificationEvaluator
                {
                    Data = scoreOutput.ScoredData
                };
                var evalOutput = experiment.Add(evalInput);

                experiment.Compile();
                experiment.SetInput(importInput.InputFile, new SimpleFileHandle(env, dataPath, false, false));
                experiment.Run();
                var data = experiment.GetOutput(evalOutput.OverallMetrics);

                var schema = data.Schema;
                var b      = schema.TryGetColumnIndex("AUC", out int aucCol);
                Assert.True(b);
                using (var cursor = data.GetRowCursor(col => col == aucCol))
                {
                    var getter = cursor.GetGetter <double>(aucCol);
                    b = cursor.MoveNext();
                    Assert.True(b);
                    double auc = 0;
                    getter(ref auc);
                    Assert.Equal(0.93, auc, 2);
                    b = cursor.MoveNext();
                    Assert.False(b);
                }
            }
        }