Add default search space for standard trainers

docs/samples/Microsoft.ML.Samples.GPU/Microsoft.ML.Samples.GPU.csproj

@@ -44,6 +44,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.ML.Onnx.TestModels" Version="$(MicrosoftMLOnnxTestModelsVersion)" />
+    <PackageReference Include="System.Text.Json" Version="$(SystemTextJsonVersion)" />
   </ItemGroup>
   <ItemGroup Condition=" '$(OS)' == 'Windows_NT'">
     <PackageReference Include="SciSharp.TensorFlow.Redist-Windows-GPU" Version="$(TensorFlowVersion)" />

docs/samples/Microsoft.ML.Samples/Microsoft.ML.Samples.csproj

@@ -977,6 +977,7 @@
     <PackageReference Include="Microsoft.ML.Onnx.TestModels" Version="$(MicrosoftMLOnnxTestModelsVersion)" />
     <PackageReference Include="SciSharp.TensorFlow.Redist" Version="$(TensorFlowVersion)" />
     <PackageReference Include="Microsoft.ML.OnnxRuntime" Version="$(MicrosoftMLOnnxRuntimeVersion)" />
+    <PackageReference Include="System.Text.Json" Version="$(SystemTextJsonVersion)" />
   </ItemGroup>
 
     <ItemGroup>

src/Microsoft.ML.Console/Microsoft.ML.Console.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <TargetFramework>net6.0</TargetFramework>
     <OutputType>Exe</OutputType>
     <AssemblyName>MML</AssemblyName>
     <StartupObject>Microsoft.ML.Tools.Console.Console</StartupObject>
@@ -27,6 +27,7 @@
     <ProjectReference Include="..\Microsoft.ML.Sweeper\Microsoft.ML.Sweeper.csproj" />
     <ProjectReference Include="..\Microsoft.ML.TensorFlow\Microsoft.ML.TensorFlow.csproj" />
     <ProjectReference Include="..\Microsoft.ML.Transforms\Microsoft.ML.Transforms.csproj" />
+    <PackageReference Include="System.Text.Json" Version="$(SystemTextJsonVersion)" />
 
     <NativeAssemblyReference Include="FastTreeNative" />
     <NativeAssemblyReference Include="CpuMathNative" />

src/Microsoft.ML.SearchSpace/Converter/ChoiceOptionConverter.cs

@@ -0,0 +1,46 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using Microsoft.ML.SearchSpace.Option;
+
+namespace Microsoft.ML.SearchSpace.Converter
+{
+    internal class ChoiceOptionConverter : JsonConverter<ChoiceOption>
+    {
+        class Schema
+        {
+            /// <summary>
+            /// must be one of "int" | "float" | "double"
+            /// </summary>
+            [JsonPropertyName("default")]
+            public object Default { get; set; }
+
+            [JsonPropertyName("choices")]
+            public object[] Choices { get; set; }
+        }
+
+        public override ChoiceOption Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            var schema = JsonSerializer.Deserialize<Schema>(ref reader, options);
+
+            return new ChoiceOption(schema.Choices, schema.Default);
+        }
+
+        public override void Write(Utf8JsonWriter writer, ChoiceOption value, JsonSerializerOptions options)
+        {
+            var schema = new Schema
+            {
+                Choices = value.Choices,
+                Default = value.SampleFromFeatureSpace(value.Default),
+            };
+
+            JsonSerializer.Serialize(writer, schema, options);
+        }
+    }
+}

src/Microsoft.ML.SearchSpace/Converter/NumericOptionConverter.cs

@@ -0,0 +1,84 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using Microsoft.ML.SearchSpace.Option;
+
+namespace Microsoft.ML.SearchSpace.Converter
+{
+    internal class NumericOptionConverter : JsonConverter<UniformNumericOption>
+    {
+        class Schema
+        {
+            /// <summary>
+            /// must be one of "int" | "float" | "double"
+            /// </summary>
+            [JsonPropertyName("type")]
+            public string Type { get; set; }
+
+            [JsonPropertyName("default")]
+            public object Default { get; set; }
+
+            [JsonPropertyName("min")]
+            public object Min { get; set; }
+
+            [JsonPropertyName("max")]
+            public object Max { get; set; }
+
+            [JsonPropertyName("log_base")]
+            public bool LogBase { get; set; }
+        }
+
+        public override UniformNumericOption Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            var schema = JsonSerializer.Deserialize<Schema>(ref reader, options);
+
+            return schema.Type switch
+            {
+                "int" => new UniformIntOption(Convert.ToInt32(schema.Min), Convert.ToInt32(schema.Max), schema.LogBase, Convert.ToInt32(schema.Default)),
+                "float" => new UniformSingleOption(Convert.ToSingle(schema.Min), Convert.ToSingle(schema.Max), schema.LogBase, Convert.ToSingle(schema.Default)),
+                "double" => new UniformDoubleOption(Convert.ToDouble(schema.Min), Convert.ToDouble(schema.Max), schema.LogBase, Convert.ToDouble(schema.Default)),
+                _ => throw new ArgumentException($"unknown schema type: {schema.Type}"),
+            };
+        }
+
+        public override void Write(Utf8JsonWriter writer, UniformNumericOption value, JsonSerializerOptions options)
+        {
+            var schema = value switch
+            {
+                UniformIntOption intOption => new Schema
+                {
+                    Type = "int",
+                    Default = intOption.SampleFromFeatureSpace(intOption.Default).AsType<int>(),
+                    Min = Convert.ToInt32(intOption.Min),
+                    Max = Convert.ToInt32(intOption.Max),
+                    LogBase = intOption.LogBase,
+                },
+                UniformDoubleOption doubleOption => new Schema
+                {
+                    Type = "double",
+                    Default = doubleOption.SampleFromFeatureSpace(doubleOption.Default).AsType<double>(),
+                    Min = doubleOption.Min,
+                    Max = doubleOption.Max,
+                    LogBase = doubleOption.LogBase,
+                },
+                UniformSingleOption singleOption => new Schema
+                {
+                    Type = "float",
+                    Default = singleOption.SampleFromFeatureSpace(singleOption.Default).AsType<Single>(),
+                    Min = Convert.ToSingle(singleOption.Min),
+                    Max = Convert.ToSingle(singleOption.Max),
+                    LogBase = singleOption.LogBase,
+                },
+                _ => throw new ArgumentException("unknown type"),
+            };
+
+            JsonSerializer.Serialize(writer, schema, options);
+        }
+    }
+}

src/Microsoft.ML.SearchSpace/Converter/OptionConverter.cs

@@ -0,0 +1,66 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using Microsoft.ML.SearchSpace.Option;
+
+namespace Microsoft.ML.SearchSpace.Converter
+{
+    internal class OptionConverter : JsonConverter<OptionBase>
+    {
+        public override OptionBase Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            try
+            {
+                return JsonSerializer.Deserialize<SearchSpace>(ref reader, options);
+            }
+            catch (Exception)
+            {
+                // try choice option
+            }
+
+            try
+            {
+                return JsonSerializer.Deserialize<ChoiceOption>(ref reader, options);
+            }
+            catch (Exception)
+            {
+                // try numeric option
+            }
+
+            try
+            {
+                return JsonSerializer.Deserialize<UniformNumericOption>(ref reader, options);
+            }
+            catch (Exception)
+            {
+                throw new ArgumentException("unknown option type");
+            }
+        }
+
+        public override void Write(Utf8JsonWriter writer, OptionBase value, JsonSerializerOptions options)
+        {
+            if (value is SearchSpace ss)
+            {
+                JsonSerializer.Serialize(writer, ss, options);
+            }
+            else if (value is ChoiceOption choiceOption)
+            {
+                JsonSerializer.Serialize(writer, choiceOption, options);
+            }
+            else if (value is UniformNumericOption uniformNumericOption)
+            {
+                JsonSerializer.Serialize(writer, uniformNumericOption, options);
+            }
+            else
+            {
+                throw new ArgumentException("unknown option type");
+            }
+        }
+    }
+}

src/Microsoft.ML.SearchSpace/Converter/SearchSpaceConverter.cs

@@ -0,0 +1,28 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using Microsoft.ML.SearchSpace.Option;
+
+namespace Microsoft.ML.SearchSpace.Converter
+{
+    internal class SearchSpaceConverter : JsonConverter<SearchSpace>
+    {
+        public override SearchSpace Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            var optionKVPairs = JsonSerializer.Deserialize<Dictionary<string, OptionBase>>(ref reader, options);
+
+            return new SearchSpace(optionKVPairs);
+        }
+
+        public override void Write(Utf8JsonWriter writer, SearchSpace value, JsonSerializerOptions options)
+        {
+            JsonSerializer.Serialize<IDictionary<string, OptionBase>>(value, options);
+        }
+    }
+}

src/Microsoft.ML.SearchSpace/Microsoft.ML.SearchSpace.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
-    <IncludeInPackage>Microsoft.ML.AutoML</IncludeInPackage>
+    <IncludeInPackage>Microsoft.ML.Core</IncludeInPackage>
     <DisableImplicitNamespaceImports>true</DisableImplicitNamespaceImports>
     <NoWarn>MSML_ContractsCheckMessageNotLiteralOrIdentifier</NoWarn>
     <LangVersion>9.0</LangVersion>

src/Microsoft.ML.SearchSpace/Option/ChoiceOption.cs

@@ -5,6 +5,8 @@
 using System;
 using System.Diagnostics.Contracts;
 using System.Linq;
+using System.Text.Json.Serialization;
+using Microsoft.ML.SearchSpace.Converter;
 
 #nullable enable
 
@@ -13,6 +15,7 @@ namespace Microsoft.ML.SearchSpace.Option
     /// <summary>
     /// This class represent option for discrete value, such as string, enum, etc..
     /// </summary>
+    [JsonConverter(typeof(ChoiceOptionConverter))]
     public sealed class ChoiceOption : OptionBase
     {
         private readonly UniformSingleOption _option;

src/Microsoft.ML.SearchSpace/Option/NestOption.cs

@@ -11,9 +11,9 @@
 namespace Microsoft.ML.SearchSpace.Option
 {
     /// <summary>
-    /// This class represent nest option, which is an option that contains other options, like <see cref="ChoiceOption"/>, <see cref="UniformNumericOption"/> or even <see cref="NestOption"/> itself.
+    /// This class represent nest option, which is an option that contains other options, like <see cref="ChoiceOption"/>, <see cref="UniformNumericOption"/> or even <see cref="SearchSpace"/> itself.
     /// </summary>
-    public sealed class NestOption : OptionBase, IDictionary<string, OptionBase>
+    public sealed class SearchSpace : OptionBase, IDictionary<string, OptionBase>
     {
         private readonly Dictionary<string, OptionBase> _options = new Dictionary<string, OptionBase>();
 

src/Microsoft.ML.SearchSpace/Option/OptionBase.cs

@@ -5,11 +5,15 @@
 
 #nullable enable
 
+using System.Text.Json.Serialization;
+using Microsoft.ML.SearchSpace.Converter;
+
 namespace Microsoft.ML.SearchSpace.Option
 {
     /// <summary>
     /// abstrace class for Option.
     /// </summary>
+    [JsonConverter(typeof(OptionConverter))]
     public abstract class OptionBase
     {
         /// <summary>
@@ -37,7 +41,7 @@ public abstract class OptionBase
 
         /// <summary>
         /// Gets the step of this option. The <see cref="Step"/> is used to determine the number of grid this option should be divided into. In <see cref="ChoiceOption"/>, it's always the length of
-        /// <see cref="ChoiceOption.Choices"/>. And in <see cref="UniformNumericOption"/>, it's always [null]. And in <see cref="SearchSpace"/>, it's a combination of all <see cref="Step"/> in its options.
+        /// <see cref="ChoiceOption.Choices"/>. And in <see cref="UniformNumericOption"/>, it's always [null]. And in <see cref="ML.SearchSpace.SearchSpace"/>, it's a combination of all <see cref="Step"/> in its options.
         /// </summary>
         public abstract int?[] Step { get; }
     }

src/Microsoft.ML.SearchSpace/Option/UniformNumericOption.cs

@@ -5,12 +5,15 @@
 using System;
 using System.Diagnostics.Contracts;
 using System.Linq;
+using System.Text.Json.Serialization;
+using Microsoft.ML.SearchSpace.Converter;
 
 namespace Microsoft.ML.SearchSpace.Option
 {
     /// <summary>
     /// abstract class for numeric option.
     /// </summary>
+    [JsonConverter(typeof(NumericOptionConverter))]
     public abstract class UniformNumericOption : OptionBase
     {
         /// <summary>