/// <summary>
/// Create method corresponding to SignatureDataTransform.
/// </summary>
public static IDataTransform Create(IHostEnvironment env, Arguments args, IDataView input)
{
Contracts.CheckValue(env, nameof(env));
var host = env.Register(RegistrationName);
host.CheckValue(args, nameof(args));
host.CheckValue(input, nameof(input));
args.Check(host);
var scores = default(VBuffer <Single>);
TrainCore(host, input, args, ref scores);
using (var ch = host.Start("Dropping Slots"))
{
int selectedCount;
var column = CreateDropSlotsColumn(args, ref scores, out selectedCount);
if (column == null)
{
ch.Info("No features are being dropped.");
return(NopTransform.CreateIfNeeded(host, input));
}
ch.Info(MessageSensitivity.Schema, "Selected {0} slots out of {1} in column '{2}'", selectedCount, scores.Length, args.FeatureColumn);
var dsArgs = new DropSlotsTransform.Arguments();
dsArgs.Column = new[] { column };
return(new DropSlotsTransform(host, dsArgs, input));
}
}
/// <summary>
/// Create method corresponding to SignatureDataTransform.
/// </summary>
public static IDataTransform Create(IHostEnvironment env, Arguments args, IDataView input)
{
Contracts.CheckValue(env, nameof(env));
var host = env.Register(RegistrationName);
host.CheckValue(args, nameof(args));
host.CheckValue(input, nameof(input));
host.CheckUserArg(Utils.Size(args.Column) > 0, nameof(args.Column));
host.CheckUserArg(args.SlotsInOutput > 0, nameof(args.SlotsInOutput));
host.CheckNonWhiteSpace(args.LabelColumn, nameof(args.LabelColumn));
host.Check(args.NumBins > 1, "numBins must be greater than 1.");
using (var ch = host.Start("Selecting Slots"))
{
ch.Info("Computing mutual information");
var sw = new Stopwatch();
sw.Start();
var colSet = new HashSet <string>();
foreach (var col in args.Column)
{
if (!colSet.Add(col))
{
ch.Warning("Column '{0}' specified multiple time.", col);
}
}
var colArr = colSet.ToArray();
var colSizes = new int[colArr.Length];
var scores = MutualInformationFeatureSelectionUtils.TrainCore(host, input, args.LabelColumn, colArr,
args.NumBins, colSizes);
sw.Stop();
ch.Info("Finished mutual information computation in {0}", sw.Elapsed);
ch.Info("Selecting features to drop");
var threshold = ComputeThreshold(scores, args.SlotsInOutput, out int tiedScoresToKeep);
var columns = CreateDropSlotsColumns(colArr, colArr.Length, scores, threshold, tiedScoresToKeep, out int[] selectedCount);
if (columns.Count <= 0)
{
ch.Info("No features are being dropped.");
return(NopTransform.CreateIfNeeded(host, input));
}
for (int i = 0; i < selectedCount.Length; i++)
{
ch.Info("Selected {0} slots out of {1} in column '{2}'", selectedCount[i], colSizes[i], colArr[i]);
}
ch.Info("Total number of slots selected: {0}", selectedCount.Sum());
var dsArgs = new DropSlotsTransform.Arguments();
dsArgs.Column = columns.ToArray();
var ds = new DropSlotsTransform(host, dsArgs, input);
ch.Done();
return(ds);
}
}
protected override IDataView GetPerInstanceMetricsCore(IDataView perInst, RoleMappedSchema schema)
{
// Wrap with a DropSlots transform to pick only the first _numTopClusters slots.
if (perInst.Schema.TryGetColumnIndex(ClusteringPerInstanceEvaluator.SortedClusters, out int index))
{
var type = perInst.Schema.GetColumnType(index);
if (_numTopClusters < type.VectorSize)
{
var args = new DropSlotsTransform.Arguments
{
Column = new DropSlotsTransform.Column[]
{
new DropSlotsTransform.Column()
{
Name = ClusteringPerInstanceEvaluator.SortedClusters,
Slots = new[] {
new DropSlotsTransform.Range()
{
Min = _numTopClusters
}
}
}
}
};
perInst = new DropSlotsTransform(Host, args, perInst);
}
}
if (perInst.Schema.TryGetColumnIndex(ClusteringPerInstanceEvaluator.SortedClusterScores, out index))
{
var type = perInst.Schema.GetColumnType(index);
if (_numTopClusters < type.VectorSize)
{
var args = new DropSlotsTransform.Arguments
{
Column = new DropSlotsTransform.Column[]
{
new DropSlotsTransform.Column()
{
Name = ClusteringPerInstanceEvaluator.SortedClusterScores,
Slots = new[] {
new DropSlotsTransform.Range()
{
Min = _numTopClusters
}
}
}
}
};
perInst = new DropSlotsTransform(Host, args, perInst);
}
}
return(perInst);
}
/// <summary>
/// Create method corresponding to SignatureDataTransform.
/// </summary>
public static IDataTransform Create(IHostEnvironment env, Arguments args, IDataView input)
{
Contracts.CheckValue(env, nameof(env));
var host = env.Register(RegistrationName);
host.CheckValue(args, nameof(args));
host.CheckValue(input, nameof(input));
host.CheckUserArg(Utils.Size(args.Column) > 0, nameof(args.Column));
host.CheckUserArg(args.Count > 0, nameof(args.Count));
int[] colSizes;
var scores = CountFeatureSelectionUtils.Train(host, input, args.Column, out colSizes);
var size = args.Column.Length;
using (var ch = host.Start("Dropping Slots"))
{
int[] selectedCount;
var columns = CreateDropSlotsColumns(args, size, scores, out selectedCount);
if (columns.Count <= 0)
{
ch.Info("No features are being dropped.");
return(NopTransform.CreateIfNeeded(host, input));
}
for (int i = 0; i < selectedCount.Length; i++)
{
ch.Info(MessageSensitivity.Schema, "Selected {0} slots out of {1} in column '{2}'", selectedCount[i], colSizes[i], args.Column[i]);
}
ch.Info("Total number of slots selected: {0}", selectedCount.Sum());
var dsArgs = new DropSlotsTransform.Arguments();
dsArgs.Column = columns.ToArray();
ch.Done();
return(new DropSlotsTransform(host, dsArgs, input));
}
}