"Can't re-use trainer!" message on CV with AveragePerceptron.

[sfilipi]

Running CV with Average Perceptron throws: "Can't re-use trainer":

Dataset: wikiDetox

Code:

var data= mlContext.Data.TextReader(new TextLoader.Arguments()
                {
                    Separator = "tab",
                    HasHeader = true,
                    Column = new[]
                    {
                        new TextLoader.Column("Sentiment", DataKind.BL, 0),
                        new TextLoader.Column("SentimentText", DataKind.Text, 1)
                    }
                }).Read(dataFile);

var pipeline = mlContext.Transforms.Text.FeaturizeText("SentimentText", "Features")
                    .Append(mlContext.BinaryClassification.Trainers.AveragedPerceptron(label: "Sentiment", features: "Features"));

[Zruty0]

Actually, upon cursory look it seems that our OnlineLinearTrainer is stateful. This is horrible, the estimators are not supposed to be stateful. We will need to rewrite OnlineLinearTrainer.

[Zruty0]

@GalOshri you also hit this bug

[sfilipi]

@TomFinley do you want to close this with pr #1455