get next pipeline API rev -- refactor API to consume column dimension…

…s, purpose, type, and name instead of available trainers & transforms (dotnet#19)

src/AutoML/API/MLContextAutoFitExtensions.cs

@@ -47,11 +47,6 @@ internal static RegressionResult AutoFit(this RegressionContext context,
             var bestResult = new RegressionIterationResult(bestPipeline.Model, (RegressionMetrics)bestPipeline.EvaluatedMetrics, bestPipeline.ScoredValidationData, bestPipeline.Pipeline.ToPipeline());
             return new RegressionResult(bestResult, results);
         }
-
-        public static Pipeline GetPipeline(this RegressionContext context, IDataView dataView, string label)
-        {
-            return PipelineSuggesterApi.GetPipeline(TaskKind.Regression, dataView, label);
-        }
     }
 
     public static class BinaryClassificationExtensions
@@ -96,11 +91,6 @@ internal static BinaryClassificationResult AutoFit(this BinaryClassificationCont
             var bestResult = new BinaryClassificationItertionResult(bestPipeline.Model, (BinaryClassificationMetrics)bestPipeline.EvaluatedMetrics, bestPipeline.ScoredValidationData, bestPipeline.Pipeline.ToPipeline());
             return new BinaryClassificationResult(bestResult, results);
         }
-
-        public static Pipeline GetPipeline(this BinaryClassificationContext context, IDataView dataView, string label)
-        {
-            return PipelineSuggesterApi.GetPipeline(TaskKind.BinaryClassification, dataView, label);
-        }
     }
 
     public static class MulticlassExtensions
@@ -144,11 +134,6 @@ internal static MulticlassClassificationResult AutoFit(this MulticlassClassifica
             var bestResult = new MulticlassClassificationIterationResult(bestPipeline.Model, (MultiClassClassifierMetrics)bestPipeline.EvaluatedMetrics, bestPipeline.ScoredValidationData, bestPipeline.Pipeline.ToPipeline());
             return new MulticlassClassificationResult(bestResult, results);
         }
-
-        public static Pipeline GetPipeline(this MulticlassClassificationContext context, IDataView dataView, string label)
-        {
-            return PipelineSuggesterApi.GetPipeline(TaskKind.MulticlassClassification, dataView, label);
-        }
     }
 
     public class BinaryClassificationResult

src/AutoML/API/Pipeline.cs

@@ -5,11 +5,11 @@ namespace Microsoft.ML.Auto
 {
     public class Pipeline
     {
-        public PipelineNode[] Elements { get; set; }
+        public PipelineNode[] Nodes { get; set; }
 
-        public Pipeline(PipelineNode[] elements)
+        public Pipeline(PipelineNode[] nodes)
         {
-            Elements = elements;
+            Nodes = nodes;
         }
 
         // (used by Newtonsoft)
@@ -27,31 +27,31 @@ public IEstimator<ITransformer> ToEstimator()
     public class PipelineNode
     {
         public string Name { get; set; }
-        public PipelineNodeType ElementType { get; set; }
+        public PipelineNodeType NodeType { get; set; }
         public string[] InColumns { get; set; }
         public string[] OutColumns { get; set; }
         public IDictionary<string, object> Properties { get; set; }
 
-        public PipelineNode(string name, PipelineNodeType elementType,
+        public PipelineNode(string name, PipelineNodeType nodeType,
             string[] inColumns, string[] outColumns,
             IDictionary<string, object> properties = null)
         {
             Name = name;
-            ElementType = elementType;
+            NodeType = nodeType;
             InColumns = inColumns;
             OutColumns = outColumns;
             Properties = properties ?? new Dictionary<string, object>();
         }
 
-        public PipelineNode(string name, PipelineNodeType elementType, 
+        public PipelineNode(string name, PipelineNodeType nodeType, 
             string inColumn, string outColumn, IDictionary<string, object> properties = null) :
-            this(name, elementType, new string[] { inColumn }, new string[] { outColumn }, properties)
+            this(name, nodeType, new string[] { inColumn }, new string[] { outColumn }, properties)
         {
         }
 
-        public PipelineNode(string name, PipelineNodeType elementType,
+        public PipelineNode(string name, PipelineNodeType nodeType,
             string[] inColumns, string outColumn, IDictionary<string, object> properties = null) :
-            this(name, elementType, inColumns, new string[] { outColumn }, properties)
+            this(name, nodeType, inColumns, new string[] { outColumn }, properties)
         {
         }
 

src/AutoML/AutoFitter/AutoFitter.cs

@@ -16,22 +16,22 @@ internal class AutoFitter
         private readonly IDebugLogger _debugLogger;
         private readonly IList<InferredPipelineRunResult> _history;
         private readonly string _label;
-        private readonly MLContext _mlContext;
+        private readonly MLContext _context;
         private readonly OptimizingMetricInfo _optimizingMetricInfo;
         private readonly IDictionary<string, ColumnPurpose> _purposeOverrides;
         private readonly AutoFitSettings _settings;
         private readonly IDataView _trainData;
         private readonly TaskKind _task;
         private readonly IDataView _validationData;
 
-        public AutoFitter(MLContext mlContext, OptimizingMetricInfo metricInfo, AutoFitSettings settings, 
+        public AutoFitter(MLContext context, OptimizingMetricInfo metricInfo, AutoFitSettings settings, 
             TaskKind task, string label, IDataView trainData, IDataView validationData,
             IDictionary<string, ColumnPurpose> purposeOverrides, IDebugLogger debugLogger)
         {
             _debugLogger = debugLogger;
             _history = new List<InferredPipelineRunResult>();
             _label = label;
-            _mlContext = mlContext;
+            _context = context;
             _optimizingMetricInfo = metricInfo;
             _settings = settings ?? new AutoFitSettings();
             _purposeOverrides = purposeOverrides;
@@ -49,13 +49,13 @@ public InferredPipelineRunResult[] Fit()
         private void IteratePipelinesAndFit()
         {
             var stopwatch = Stopwatch.StartNew();
-            var transforms = TransformInferenceApi.InferTransforms(_mlContext, _trainData, _label, _purposeOverrides);
-            var availableTrainers = RecipeInference.AllowedTrainers(_mlContext, _task, _settings.StoppingCriteria.MaxIterations);
+            var columns = AutoMlUtils.GetColumnInfoTuples(_context, _trainData, _label, _purposeOverrides);
 
             do
             {
                 // get next pipeline
-                var pipeline = PipelineSuggester.GetNextInferredPipeline(_history, transforms, availableTrainers, _optimizingMetricInfo.IsMaximizing);
+                var iterationsRemaining = _settings.StoppingCriteria.MaxIterations - _history.Count;
+                var pipeline = PipelineSuggester.GetNextInferredPipeline(_history, columns, _task, iterationsRemaining, _optimizingMetricInfo.IsMaximizing);
 
                 // break if no candidates returned, means no valid pipeline available
                 if (pipeline == null)
@@ -113,11 +113,11 @@ private object GetEvaluatedMetrics(IDataView scoredData)
             switch(_task)
             {
                 case TaskKind.BinaryClassification:
-                    return _mlContext.BinaryClassification.EvaluateNonCalibrated(scoredData);
+                    return _context.BinaryClassification.EvaluateNonCalibrated(scoredData);
                 case TaskKind.MulticlassClassification:
-                    return _mlContext.MulticlassClassification.Evaluate(scoredData);
+                    return _context.MulticlassClassification.Evaluate(scoredData);
                 case TaskKind.Regression:
-                    return _mlContext.Regression.Evaluate(scoredData);
+                    return _context.Regression.Evaluate(scoredData);
                 // should not be possible to reach here
                 default:
                     throw new InvalidOperationException($"unsupported machine learning task type {_task}");

src/AutoML/AutoFitter/InferredPipeline.cs

@@ -70,17 +70,17 @@ public static InferredPipeline FromPipeline(Pipeline pipeline)
             var transforms = new List<SuggestedTransform>();
             SuggestedTrainer trainer = null;
 
-            foreach(var pipelineNode in pipeline.Elements)
+            foreach(var pipelineNode in pipeline.Nodes)
             {
-                if(pipelineNode.ElementType == PipelineNodeType.Trainer)
+                if(pipelineNode.NodeType == PipelineNodeType.Trainer)
                 {
                     var trainerName = (TrainerName)Enum.Parse(typeof(TrainerName), pipelineNode.Name);
                     var trainerExtension = TrainerExtensionCatalog.GetTrainerExtension(trainerName);
                     var stringParamVals = pipelineNode.Properties.Select(prop => new StringParameterValue(prop.Key, prop.Value.ToString()));
                     var hyperParamSet = new ParameterSet(stringParamVals);
                     trainer = new SuggestedTrainer(context, trainerExtension, hyperParamSet);
                 }
-                else if (pipelineNode.ElementType == PipelineNodeType.Transform)
+                else if (pipelineNode.NodeType == PipelineNodeType.Transform)
                 {
                     var estimatorName = (EstimatorName)Enum.Parse(typeof(EstimatorName), pipelineNode.Name);
                     var estimatorExtension = EstimatorExtensionCatalog.GetExtension(estimatorName);

src/AutoML/AutoMlUtils.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using Microsoft.ML.Data;
 using Microsoft.ML.Transforms;
@@ -29,5 +30,20 @@ public static IDataView Take(this IDataView data, int count)
             var take = SkipTakeFilter.Create(env, new SkipTakeFilter.TakeArguments { Count = count }, data);
             return new CacheDataView(env, data, Enumerable.Range(0, data.Schema.Count).ToArray());
         }
+
+        public static (string, ColumnType, ColumnPurpose, ColumnDimensions)[] GetColumnInfoTuples(MLContext context,
+            IDataView data, string label, IDictionary<string, ColumnPurpose> purposeOverrides)
+        {
+            var purposes = PurposeInference.InferPurposes(context, data, label, purposeOverrides);
+            var colDimensions = DatasetDimensionsApi.CalcColumnDimensions(data, purposes);
+            var cols = new (string, ColumnType, ColumnPurpose, ColumnDimensions)[data.Schema.Count];
+            for (var i = 0; i < cols.Length; i++)
+            {
+                var schemaCol = data.Schema[i];
+                var col = (schemaCol.Name, schemaCol.Type, purposes[i].Purpose, colDimensions[i]);
+                cols[i] = col;
+            }
+            return cols;
+        }
     }
 }

src/AutoML/DatasetDimensions/ColumnDimensions.cs

@@ -0,0 +1,14 @@
+namespace Microsoft.ML.Auto
+{
+    internal class ColumnDimensions
+    {
+        public int? Cardinality;
+        public bool? HasMissing;
+
+        public ColumnDimensions(int? cardinality, bool? hasMissing)
+        {
+            Cardinality = cardinality;
+            HasMissing = hasMissing;
+        }
+    }
+}

src/AutoML/DatasetDimensions/DatasetDimensionsApi.cs

@@ -0,0 +1,45 @@
+using Microsoft.ML.Data;
+
+namespace Microsoft.ML.Auto
+{
+    internal class DatasetDimensionsApi
+    {
+        private const int MaxRowsToRead = 1000;
+
+        public static ColumnDimensions[] CalcColumnDimensions(IDataView data, PurposeInference.Column[] purposes)
+        {
+            data = data.Take(MaxRowsToRead);
+
+            var colDimensions = new ColumnDimensions[data.Schema.Count];
+
+            for (var i = 0; i < data.Schema.Count; i++)
+            {
+                var column = data.Schema[i];
+                var purpose = purposes[i];
+
+                // default column dimensions
+                int? cardinality = null;
+                bool? hasMissing = null;
+
+                // if categorical text feature, calc cardinality
+                if(column.Type.ItemType().IsText() && purpose.Purpose == ColumnPurpose.CategoricalFeature)
+                {
+                    cardinality = DatasetDimensionsUtil.GetTextColumnCardinality(data, i);
+                }
+
+                // if numeric feature, discover missing values
+                // todo: upgrade logic to consider R8?
+                if (column.Type.ItemType() == NumberType.R4)
+                {
+                    hasMissing = column.Type.IsVector() ? 
+                        DatasetDimensionsUtil.HasMissingNumericVector(data, i) : 
+                        DatasetDimensionsUtil.HasMissingNumericSingleValue(data, i);
+                }
+
+                colDimensions[i] = new ColumnDimensions(cardinality, hasMissing);
+            }
+
+            return colDimensions;
+        }
+    }
+}

src/AutoML/DatasetDimensions/DatasetDimensionsUtil.cs

@@ -0,0 +1,62 @@
+using System;
+using System.Collections.Generic;
+using Microsoft.ML.Data;
+
+namespace Microsoft.ML.Auto
+{
+    internal static class DatasetDimensionsUtil
+    {
+        public static int GetTextColumnCardinality(IDataView data, int colIndex)
+        {
+            var seen = new HashSet<string>();
+            using (var cursor = data.GetRowCursor(x => x == colIndex))
+            {
+                var getter = cursor.GetGetter<ReadOnlyMemory<char>>(colIndex);
+                while (cursor.MoveNext())
+                {
+                    var value = default(ReadOnlyMemory<char>);
+                    getter(ref value);
+                    var valueStr = value.ToString();
+                    seen.Add(valueStr);
+                }
+            }
+            return seen.Count;
+        }
+
+        public static bool HasMissingNumericSingleValue(IDataView data, int colIndex)
+        {
+            using (var cursor = data.GetRowCursor(x => x == colIndex))
+            {
+                var getter = cursor.GetGetter<Single>(colIndex);
+                var value = default(Single);
+                while (cursor.MoveNext())
+                {
+                    getter(ref value);
+                    if (Single.IsNaN(value))
+                    {
+                        return true;
+                    }
+                }
+                return false;
+            }
+        }
+
+        public static bool HasMissingNumericVector(IDataView data, int colIndex)
+        {
+            using (var cursor = data.GetRowCursor(x => x == colIndex))
+            {
+                var getter = cursor.GetGetter<VBuffer<Single>>(colIndex);
+                var value = default(VBuffer<Single>);
+                while (cursor.MoveNext())
+                {
+                    getter(ref value);
+                    if (VBufferUtils.HasNaNs(value))
+                    {
+                        return true;
+                    }
+                }
+                return false;
+            }
+        }
+    }
+}

src/AutoML/PipelineSuggesters/PipelineSuggester.cs

@@ -5,6 +5,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Microsoft.ML.Data;
 
 namespace Microsoft.ML.Auto
 {
@@ -13,23 +14,29 @@ internal static class PipelineSuggester
         private const int TopKTrainers = 3;
 
         public static Pipeline GetNextPipeline(IEnumerable<PipelineRunResult> history,
-            IEnumerable<SuggestedTransform> transforms,
-            IEnumerable<SuggestedTrainer> availableTrainers,
+            (string, ColumnType, ColumnPurpose, ColumnDimensions)[] columns,
+            TaskKind task,
+            int iterationsRemaining,
             bool isMaximizingMetric = true)
         {
             var inferredHistory = history.Select(r => InferredPipelineRunResult.FromPipelineRunResult(r));
-            var nextInferredPipeline = GetNextInferredPipeline(inferredHistory,
-                transforms, availableTrainers, isMaximizingMetric);
+            var nextInferredPipeline = GetNextInferredPipeline(inferredHistory, columns, task, iterationsRemaining, isMaximizingMetric);
             return nextInferredPipeline.ToPipeline();
         }
 
         public static InferredPipeline GetNextInferredPipeline(IEnumerable<InferredPipelineRunResult> history,
-            IEnumerable<SuggestedTransform> transforms,
-            IEnumerable<SuggestedTrainer> availableTrainers,
+            (string, ColumnType, ColumnPurpose, ColumnDimensions)[] columns,
+            TaskKind task,
+            int iterationsRemaining,
             bool isMaximizingMetric = true)
         {
+            var context = new MLContext();
+
+            var availableTrainers = RecipeInference.AllowedTrainers(context, TaskKind.BinaryClassification, history.Count() + iterationsRemaining);
+            var transforms = TransformInferenceApi.InferTransforms(context, columns);
+
             // if we haven't run all pipelines once
-            if(history.Count() < availableTrainers.Count())
+            if (history.Count() < availableTrainers.Count())
             {
                 return GetNextFirstStagePipeline(history, availableTrainers, transforms);
             }