Add Seed property to MLContext and use as default for data splits

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

@@ -82,6 +82,15 @@ internal interface ICancelable
         bool IsCanceled { get; }
     }
 
+    [BestFriend]
+    internal interface ISeededEnvironment : IHostEnvironment
+    {
+        /// <summary>
+        /// The seed property that, if assigned, makes components requiring randomness behave deterministically.
+        /// </summary>
+        int? Seed { get; }
+    }
+
     /// <summary>
     /// A host is coupled to a component and provides random number generation and concurrency guidance.
     /// Note that the random number generation, like the host environment methods, should be accessed only

src/Microsoft.ML.Core/Environment/ConsoleEnvironment.cs

@@ -366,24 +366,7 @@ protected override void Dispose(bool disposing)
         public ConsoleEnvironment(int? seed = null, bool verbose = false,
             MessageSensitivity sensitivity = MessageSensitivity.All,
             TextWriter outWriter = null, TextWriter errWriter = null, TextWriter testWriter = null)
-            : this(RandomUtils.Create(seed), verbose, sensitivity, outWriter, errWriter, testWriter)
-        {
-        }
-
-        // REVIEW: do we really care about custom random? If we do, let's make this ctor public.
-        /// <summary>
-        /// Create an ML.NET environment for local execution, with console feedback.
-        /// </summary>
-        /// <param name="rand">An custom source of randomness to use in the environment.</param>
-        /// <param name="verbose">Set to <c>true</c> for fully verbose logging.</param>
-        /// <param name="sensitivity">Allowed message sensitivity.</param>
-        /// <param name="outWriter">Text writer to print normal messages to.</param>
-        /// <param name="errWriter">Text writer to print error messages to.</param>
-        /// <param name="testWriter">Optional TextWriter to write messages if the host is a test environment.</param>
-        private ConsoleEnvironment(Random rand, bool verbose = false,
-            MessageSensitivity sensitivity = MessageSensitivity.All,
-            TextWriter outWriter = null, TextWriter errWriter = null, TextWriter testWriter = null)
-            : base(rand, verbose, nameof(ConsoleEnvironment))
+            : base(seed, verbose, nameof(ConsoleEnvironment))
         {
             Contracts.CheckValueOrNull(outWriter);
             Contracts.CheckValueOrNull(errWriter);

src/Microsoft.ML.Core/Environment/HostEnvironmentBase.cs

@@ -93,7 +93,7 @@ internal interface IMessageSource
     /// query progress.
     /// </summary>
     [BestFriend]
-    internal abstract class HostEnvironmentBase<TEnv> : ChannelProviderBase, IHostEnvironment, IChannelProvider, ICancelable
+    internal abstract class HostEnvironmentBase<TEnv> : ChannelProviderBase, ISeededEnvironment, IChannelProvider, ICancelable
         where TEnv : HostEnvironmentBase<TEnv>
     {
         void ICancelable.CancelExecution()
@@ -330,6 +330,9 @@ public void RemoveListener(Action<IMessageSource, TMessage> listenerFunc)
 
         // The random number generator for this host.
         private readonly Random _rand;
+
+        public int? Seed { get; }
+
         // A dictionary mapping the type of message to the Dispatcher that gets the strongly typed dispatch delegate.
         protected readonly ConcurrentDictionary<Type, Dispatcher> ListenerDict;
 
@@ -345,14 +348,14 @@ public void RemoveListener(Action<IMessageSource, TMessage> listenerFunc)
         private readonly List<WeakReference<IHost>> _children;
 
         /// <summary>
-        ///  The main constructor.
+        /// The main constructor.
         /// </summary>
-        protected HostEnvironmentBase(Random rand, bool verbose,
+        protected HostEnvironmentBase(int? seed, bool verbose,
             string shortName = null, string parentFullName = null)
             : base(shortName, parentFullName, verbose)
         {
-            Contracts.CheckValueOrNull(rand);
-            _rand = rand ?? RandomUtils.Create();
+            Seed = seed;
+            _rand = RandomUtils.Create(Seed);
             ListenerDict = new ConcurrentDictionary<Type, Dispatcher>();
             ProgressTracker = new ProgressReporting.ProgressTracker(this);
             _cancelLock = new object();

src/Microsoft.ML.Data/DataLoadSave/DataOperationsCatalog.cs

@@ -496,13 +496,12 @@ internal static IEnumerable<TrainTestData> CrossValidationSplit(IHostEnvironment
         internal static void EnsureGroupPreservationColumn(IHostEnvironment env, ref IDataView data, ref string samplingKeyColumn, int? seed = null)
         {
             Contracts.CheckValue(env, nameof(env));
-            var host = env.Register("rand");
             // We need to handle two cases: if samplingKeyColumn is provided, we use hashJoin to
             // build a single hash of it. If it is not, we generate a random number.
             if (samplingKeyColumn == null)
             {
                 samplingKeyColumn = data.Schema.GetTempColumnName("SamplingKeyColumn");
-                data = new GenerateNumberTransform(env, data, samplingKeyColumn, (uint?)(seed ?? host.Rand.Next()));
+                data = new GenerateNumberTransform(env, data, samplingKeyColumn, (uint?)(seed ?? ((ISeededEnvironment)env).Seed));
             }
             else
             {
@@ -518,7 +517,13 @@ internal static void EnsureGroupPreservationColumn(IHostEnvironment env, ref IDa
                     // instead of having two hash transformations.
                     var origStratCol = samplingKeyColumn;
                     samplingKeyColumn = data.Schema.GetTempColumnName(samplingKeyColumn);
-                    var columnOptions = new HashingEstimator.ColumnOptionsInternal(samplingKeyColumn, origStratCol, 30, (uint)(seed ?? host.Rand.Next()));
+                    HashingEstimator.ColumnOptionsInternal columnOptions;
+                    if (seed.HasValue)
+                        columnOptions = new HashingEstimator.ColumnOptionsInternal(samplingKeyColumn, origStratCol, 30, (uint)seed.Value);
+                    else if (((ISeededEnvironment)env).Seed.HasValue)
+                        columnOptions = new HashingEstimator.ColumnOptionsInternal(samplingKeyColumn, origStratCol, 30, (uint)((ISeededEnvironment)env).Seed.Value);
+                    else
+                        columnOptions = new HashingEstimator.ColumnOptionsInternal(samplingKeyColumn, origStratCol, 30);
                     data = new HashingEstimator(env, columnOptions).Fit(data).Transform(data);
                 }
                 else

src/Microsoft.ML.Data/MLContext.cs

@@ -14,7 +14,7 @@ namespace Microsoft.ML
     /// create components for data preparation, feature enginering, training, prediction, model evaluation.
     /// It also allows logging, execution control, and the ability set repeatable random numbers.
     /// </summary>
-    public sealed class MLContext : IHostEnvironment
+    public sealed class MLContext : ISeededEnvironment
     {
         // REVIEW: consider making LocalEnvironment and MLContext the same class instead of encapsulation.
         private readonly LocalEnvironment _env;
@@ -140,6 +140,7 @@ private void ProcessMessage(IMessageSource source, ChannelMessage message)
         IChannel IChannelProvider.Start(string name) => _env.Start(name);
         IPipe<TMessage> IChannelProvider.StartPipe<TMessage>(string name) => _env.StartPipe<TMessage>(name);
         IProgressChannel IProgressChannelProvider.StartProgressChannel(string name) => _env.StartProgressChannel(name);
+        int? ISeededEnvironment.Seed => _env.Seed;
 
         [BestFriend]
         internal void CancelExecution() => ((ICancelable)_env).CancelExecution();

src/Microsoft.ML.Data/Utilities/LocalEnvironment.cs

@@ -47,7 +47,7 @@ protected override void Dispose(bool disposing)
         /// </summary>
         /// <param name="seed">Random seed. Set to <c>null</c> for a non-deterministic environment.</param>
         public LocalEnvironment(int? seed = null)
-            : base(RandomUtils.Create(seed), verbose: false)
+            : base(seed, verbose: false)
         {
         }
 

test/Microsoft.ML.AutoML.Tests/AutoFitTests.cs

@@ -37,7 +37,7 @@ public void AutoFitBinaryTest()
         [Fact]
         public void AutoFitMultiTest()
         {
-            var context = new MLContext(1);
+            var context = new MLContext(42);
             var columnInference = context.Auto().InferColumns(DatasetUtil.TrivialMulticlassDatasetPath, DatasetUtil.TrivialMulticlassDatasetLabel);
             var textLoader = context.Data.CreateTextLoader(columnInference.TextLoaderOptions);
             var trainData = textLoader.Load(DatasetUtil.TrivialMulticlassDatasetPath);