support for booleans

src/Microsoft.ML.Data/Transforms/KeyToValue.cs

@@ -512,7 +512,7 @@ public override bool SaveOnnx(OnnxContext ctx, string srcVariableName, string ds
 
                     var labelEncoderOutput = dstVariableName;
                     var labelEncoderInput = srcVariableName;
-                    if (TypeOutput == NumberDataViewType.Double)
+                    if (TypeOutput == NumberDataViewType.Double || TypeOutput == BooleanDataViewType.Instance)
                         labelEncoderOutput = ctx.AddIntermediateVariable(NumberDataViewType.Single, "CastNodeOutput");
                     else if (TypeOutput == NumberDataViewType.Int64 || TypeOutput == NumberDataViewType.UInt16 ||
                         TypeOutput == NumberDataViewType.Int32 || TypeOutput == NumberDataViewType.Int16 ||
@@ -555,6 +555,15 @@ public override bool SaveOnnx(OnnxContext ctx, string srcVariableName, string ds
                         string[] values = Array.ConvertAll<TValue, string>(_values.GetValues().ToArray(), item => Convert.ToString(item));
                         node.AddAttribute("values_strings", values);
                     }
+                    else if (TypeOutput == BooleanDataViewType.Instance)
+                    {
+                        float[] values = Array.ConvertAll<TValue, float>(_values.GetValues().ToArray(), item => Convert.ToSingle(item));
+                        node.AddAttribute("values_floats", values);
+                        opType = "Cast";
+                        castNode = ctx.CreateNode(opType, labelEncoderOutput, dstVariableName, ctx.GetNodeName(opType), "");
+                        t = InternalDataKindExtensions.ToInternalDataKind(DataKind.Boolean).ToType();
+                        castNode.AddAttribute("to", t);
+                    }
                     else
                         return false;
 

src/Microsoft.ML.Data/Transforms/ValueToKeyMappingTransformer.cs

@@ -793,6 +793,17 @@ private void CastInputToString<T>(OnnxContext ctx, out OnnxNode node, out long[]
                 node.AddAttribute("keys_strings", terms.Select(item => item.ToString()));
             }
 
+            private void CastInputToFloat<T>(OnnxContext ctx, out OnnxNode node, out long[] termIds, string srcVariableName, int iinfo,
+                string opType, string labelEncoderOutput)
+            {
+                var castOutput = ctx.AddIntermediateVariable(NumberDataViewType.Single, "castOutput");
+                var castNode = ctx.CreateNode("Cast", srcVariableName, castOutput, ctx.GetNodeName("Cast"), "");
+                var t = InternalDataKindExtensions.ToInternalDataKind(DataKind.Single).ToType();
+                castNode.AddAttribute("to", t);
+                node = ctx.CreateNode(opType, castOutput, labelEncoderOutput, ctx.GetNodeName(opType));
+                var terms = GetTermsAndIds<T>(iinfo, out termIds);
+                node.AddAttribute("keys_floats", terms.Select(item => Convert.ToSingle(item)));
+            }
             private bool SaveAsOnnxCore(OnnxContext ctx, int iinfo, ColInfo info, string srcVariableName, string dstVariableName)
             {
                 OnnxNode node;
@@ -808,6 +819,11 @@ private bool SaveAsOnnxCore(OnnxContext ctx, int iinfo, ColInfo info, string src
                     var terms = GetTermsAndIds<ReadOnlyMemory<char>>(iinfo, out termIds);
                     node.AddAttribute("keys_strings", terms);
                 }
+                else if (type.Equals(BooleanDataViewType.Instance))
+                {
+                    // LabelEncoder doesn't support boolean tensors, so values are cast to floats
+                    CastInputToFloat<Boolean>(ctx, out node, out termIds, srcVariableName, iinfo, opType, labelEncoderOutput);
+                }
                 else if (type.Equals(NumberDataViewType.Single))
                 {
                     node = ctx.CreateNode(opType, srcVariableName, labelEncoderOutput, ctx.GetNodeName(opType));
@@ -817,13 +833,7 @@ private bool SaveAsOnnxCore(OnnxContext ctx, int iinfo, ColInfo info, string src
                 else if (type.Equals(NumberDataViewType.Double))
                 {
                     // LabelEncoder doesn't support double tensors, so values are cast to floats
-                    var castOutput = ctx.AddIntermediateVariable(NumberDataViewType.Single, "castOutput");
-                    castNode = ctx.CreateNode("Cast", srcVariableName, castOutput, ctx.GetNodeName("Cast"), "");
-                    var t = InternalDataKindExtensions.ToInternalDataKind(DataKind.Single).ToType();
-                    castNode.AddAttribute("to", t);
-                    node = ctx.CreateNode(opType, castOutput, labelEncoderOutput, ctx.GetNodeName(opType));
-                    var terms = GetTermsAndIds<double>(iinfo, out termIds);
-                    node.AddAttribute("keys_floats", terms);
+                    CastInputToFloat<Double>(ctx, out node, out termIds, srcVariableName, iinfo, opType, labelEncoderOutput);
                 }
                 else if (type.Equals(NumberDataViewType.Int64))
                 {

test/Microsoft.ML.Tests/OnnxConversionTest.cs

@@ -1209,10 +1209,13 @@ public void IndicateMissingValuesOnnxConversionTest()
         [InlineData(DataKind.UInt16)]
         [InlineData(DataKind.Double)]
         [InlineData(DataKind.String)]
+        [InlineData(DataKind.Boolean)]
         public void ValueToKeyMappingOnnxConversionTest(DataKind valueType)
         {
             var mlContext = new MLContext(seed: 1);
             string filePath = GetDataPath("type-conversion.txt");
+            if (valueType == DataKind.Boolean)
+                filePath = GetDataPath("type-conversion-boolean.txt");
 
             TextLoader.Column[] columns = new[]
             {
@@ -1249,11 +1252,11 @@ public void ValueToKeyMappingOnnxConversionTest(DataKind valueType)
         [InlineData(DataKind.UInt16)]
         [InlineData(DataKind.Double)]
         [InlineData(DataKind.String)]
+        [InlineData(DataKind.Boolean)]
         public void KeyToValueMappingOnnxConversionTest(DataKind valueType)
         {
             var mlContext = new MLContext(seed: 1);
-            string filePath = GetDataPath("type-conversion.txt");
-
+            string filePath = (valueType == DataKind.Boolean) ? GetDataPath("type-conversion-boolean.txt") : GetDataPath("type-conversion.txt");
             TextLoader.Column[] columns = new[]
             {
                 new TextLoader.Column("Value", valueType, 0, 0)

test/data/type-conversion-boolean.txt

@@ -0,0 +1 @@
+False