Exception when converting PredictedLabel from Key To Value #3090
Description
When trying to convert the output PredictedLabel from key back to value, the exception
System.InvalidOperationException
HResult=0x80131509
Message=Metadata KeyValues does not exist
Source=Microsoft.ML.Core
StackTrace:
at Microsoft.ML.Runtime.Contracts.Check(IExceptionContext ctx, Boolean f, String msg) in C:\MLDotNet2\src\Microsoft.ML.Core\Utilities\Contracts.cs:line 497
is thrown.
Code to repro:
var mlContext = new MLContext();
var textLoaderOptions = new TextLoader.Options()
{
Columns = new[]
{
new TextLoader.Column("Label", DataKind.Single, 0),
new TextLoader.Column("Row", DataKind.Single, 1),
new TextLoader.Column("Column", DataKind.Single, 2),
},
HasHeader = true,
Separators = new[] { '\t' }
};
var textLoader = mlContext.Data.CreateTextLoader(textLoaderOptions);
var data = textLoader.Load(@"C:\MLDotNet2\test\data\trivial-train.tsv");
var ap = mlContext.BinaryClassification.Trainers.AveragedPerceptron();
var ova = mlContext.MulticlassClassification.Trainers.OneVersusAll(ap);
var pipeline = mlContext.Transforms.Conversion.MapValueToKey("Label")
.Append(mlContext.Transforms.Concatenate("Features", "Row", "Column"))
.Append(ova)
.Append(mlContext.Transforms.Conversion.MapKeyToValue("PredictedLabel"));
var model = pipeline.Fit(data);Replace C:\MLDotNet2\ with path to ML.NET repo on your local machine