handle boolean type in construction utils.

src/Microsoft.ML.Api/ApiUtils.cs

@@ -21,7 +21,7 @@ private static OpCode GetAssignmentOpCode(Type t)
             // REVIEW: This should be a Dictionary<Type, OpCode> based solution.
             // DvTexts, strings, arrays, and VBuffers.
             if (t == typeof(DvInt8) || t == typeof(DvInt4) || t == typeof(DvInt2) || t == typeof(DvInt1) ||
-                t == typeof(DvBool) || t == typeof(DvText) || t == typeof(string) || t.IsArray ||
+                t == typeof(DvBool) || t==typeof(bool?) || t == typeof(DvText) || t == typeof(string) || t.IsArray ||
                 (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(VBuffer<>)) || t == typeof(DvDateTime) ||
                 t == typeof(DvDateTimeZone) || t == typeof(DvTimeSpan) || t == typeof(UInt128))
             {

src/Microsoft.ML.Api/DataViewConstructionUtils.cs

@@ -152,6 +152,19 @@ private Delegate CreateGetter(int index)
                             Ch.Assert(colType.IsText);
                             return CreateStringToTextGetter(index);
                         }
+                        else if (outputType == typeof(bool))
+                        {
+                            // Bool -> DvBool
+                            Ch.Assert(colType.IsBool);
+                            return CreateBooleanToDvBoolGetter(index);
+                        }
+                        else if (outputType == typeof(bool?))
+                        {
+                            // Bool? -> DvBool
+                            Ch.Assert(colType.IsBool);
+                            return CreateNullableBooleanToDvBoolGetter(index);
+                        }
+
                         // T -> T
                         Ch.Assert(colType.RawType == outputType);
                         del = CreateDirectGetter<int>;
@@ -197,6 +210,30 @@ private Delegate CreateStringToTextGetter(int index)
                         });
                 }
 
+                private Delegate CreateBooleanToDvBoolGetter(int index)
+                {
+                    var peek = DataView._peeks[index] as Peek<TRow, bool>;
+                    Ch.AssertValue(peek);
+                    bool buf = false;
+                    return (ValueGetter<DvBool>)((ref DvBool dst) =>
+                    {
+                        peek(GetCurrentRowObject(), Position, ref buf);
+                        dst =  (DvBool)buf;
+                    });
+                }
+
+                private Delegate CreateNullableBooleanToDvBoolGetter(int index)
+                {
+                    var peek = DataView._peeks[index] as Peek<TRow, bool?>;
+                    Ch.AssertValue(peek);
+                    bool? buf = null;
+                    return (ValueGetter<DvBool>)((ref DvBool dst) =>
+                    {
+                        peek(GetCurrentRowObject(), Position, ref buf);
+                        dst = buf.HasValue ? (DvBool)buf.Value : DvBool.NA;
+                    });
+                }
+
                 private Delegate CreateArrayToVBufferGetter<TDst>(int index)
                 {
                     var peek = DataView._peeks[index] as Peek<TRow, TDst[]>;

src/Microsoft.ML.Core/Data/DataKind.cs

@@ -207,7 +207,7 @@ public static bool TryGetDataKind(this Type type, out DataKind kind)
                 kind = DataKind.R8;
             else if (type == typeof(DvText))
                 kind = DataKind.TX;
-            else if (type == typeof(DvBool) || type == typeof(bool))
+            else if (type == typeof(DvBool) || type == typeof(bool) ||type ==typeof(bool?))
                 kind = DataKind.BL;
             else if (type == typeof(DvTimeSpan))
                 kind = DataKind.TS;

test/Microsoft.ML.Tests/LearningPipelineTests.cs

@@ -110,5 +110,54 @@ public void NoTransformPipeline()
             pipeline.Add(new FastForestBinaryClassifier());
             var model = pipeline.Train<Data, Prediction>();
         }
+
+        public class BooleanLabelData
+        {
+            [ColumnName("Features")]
+            [VectorType(2)]
+            public float[] Features;
+
+            [ColumnName("Label")]
+            public bool Label;
+        }
+
+        [Fact]
+        public void BooleanLabelPipeline()
+        {
+            var data = new BooleanLabelData[1];
+            data[0] = new BooleanLabelData();
+            data[0].Features = new float[] { 0.0f, 1.0f };
+            data[0].Label = false;
+            var pipeline = new LearningPipeline();
+            pipeline.Add(CollectionDataSource.Create(data));
+            pipeline.Add(new FastForestBinaryClassifier());
+            var model = pipeline.Train<Data, Prediction>();
+        }
+
+        public class NullableBooleanLabelData
+        {
+            [ColumnName("Features")]
+            [VectorType(2)]
+            public float[] Features;
+
+            [ColumnName("Label")]
+            public bool? Label;
+        }
+
+        [Fact]
+        public void NullableBooleanLabelPipeline()
+        {
+            var data = new NullableBooleanLabelData[2];
+            data[0] = new NullableBooleanLabelData();
+            data[0].Features = new float[] { 0.0f, 1.0f };
+            data[0].Label = null;
+            data[1] = new NullableBooleanLabelData();
+            data[1].Features = new float[] { 1.0f, 0.0f };
+            data[1].Label = false;
+            var pipeline = new LearningPipeline();
+            pipeline.Add(CollectionDataSource.Create(data));
+            pipeline.Add(new FastForestBinaryClassifier());
+            var model = pipeline.Train<Data, Prediction>();
+        }
     }
 }