/// <summary>
/// Simplify prediction of examples with action dependent features.
/// </summary>
/// <typeparam name="TExample">The type of the user example.</typeparam>
/// <typeparam name="TActionDependentFeature">The type of the user action dependent features.</typeparam>
/// <param name="vw">The vw instance.</param>
/// <param name="serializer">The serializer for <typeparamref name="TExample"/>.</param>
/// <param name="actionDependentFeatureSerializer">The serializer for <typeparamref name="TActionDependentFeature"/>.</param>
/// <param name="example">The user example.</param>
/// <param name="actionDependentFeatures">The action dependent features.</param>
/// <param name="index">The index of action dependent feature to label.</param>
/// <param name="label">The label for the selected action dependent feature.</param>
/// <returns>An ranked subset of predicted actions.</returns>
public static ActionDependentFeature <TActionDependentFeature>[] Predict <TExample, TActionDependentFeature>(
VowpalWabbit vw,
VowpalWabbitSingleExampleSerializer <TExample> serializer,
VowpalWabbitSingleExampleSerializer <TActionDependentFeature> actionDependentFeatureSerializer,
TExample example,
IReadOnlyCollection <TActionDependentFeature> actionDependentFeatures,
int?index = null,
ILabel label = null)
{
Contract.Requires(vw != null);
Contract.Requires(actionDependentFeatureSerializer != null);
Contract.Requires(example != null);
Contract.Requires(actionDependentFeatures != null);
ActionDependentFeature <TActionDependentFeature>[] predictions = null;
Execute(
vw,
serializer,
actionDependentFeatureSerializer,
example,
actionDependentFeatures,
(examples, validActionDependentFeatures, emptyActionDependentFeatures) =>
{
var ex_col = examples.ToList();
vw.Predict(ex_col);
predictions = VowpalWabbitMultiLine.GetPrediction(vw, examples, validActionDependentFeatures, emptyActionDependentFeatures);
},
index,
label);
// default to the input list
return(predictions ?? actionDependentFeatures.Select((o, i) => new ActionDependentFeature <TActionDependentFeature>(i, o)).ToArray());
}
/// <summary>
/// Predicts for these examples and returns the current prediction for it.
/// </summary>
/// <typeparam name="TPrediction">The prediction type.</typeparam>
/// <param name="predictionFactory">The prediction factory to be used. See <see cref="VowpalWabbitPredictionType"/>.</param>
/// <returns>The prediction for the this example.</returns>
protected override TPrediction PredictInternal <TPrediction>(IVowpalWabbitPredictionFactory <TPrediction> predictionFactory, VowpalWabbit vw)
{
return(this.Execute(vw, ex => vw.Predict(ex), predictionFactory));
}
/// <summary>
/// Predicts for these examples.
/// </summary>
protected override void PredictInternal(VowpalWabbit vw)
{
// unfortunately can't specify <void>
this.Execute <int>(vw, ex => vw.Predict(ex));
}
/// <summary>
/// Predicts for this example and returns the current prediction for it.
/// </summary>
/// <typeparam name="TPrediction">The prediction type.</typeparam>
/// <param name="predictionFactory">The prediction factory to be used. See <see cref="VowpalWabbitPredictionType"/>.</param>
/// <param name="vw">The VW instance that should be used for prediction.</param>
/// <returns>The prediction for the this example.</returns>
protected override TPrediction PredictInternal <TPrediction>(IVowpalWabbitPredictionFactory <TPrediction> predictionFactory, VowpalWabbit vw)
{
return(vw.Predict <TPrediction>(this.Example, predictionFactory));
}
/// <summary>
/// Predicts for this example.
/// </summary>
protected override void PredictInternal(VowpalWabbit vw)
{
vw.Predict(this.Example);
}
/// <summary>
/// Simplify prediction of examples with action dependent features.
/// </summary>
/// <typeparam name="TExample">The type of the user example.</typeparam>
/// <typeparam name="TActionDependentFeature">The type of the user action dependent features.</typeparam>
/// <param name="vw">The vw instance.</param>
/// <param name="serializer">The serializer for <typeparamref name="TExample"/>.</param>
/// <param name="actionDependentFeatureSerializer">The serializer for <typeparamref name="TActionDependentFeature"/>.</param>
/// <param name="example">The user example.</param>
/// <param name="actionDependentFeatures">The action dependent features.</param>
/// <returns>An ranked subset of predicted action indexes.</returns>
public static int[] PredictIndex <TExample, TActionDependentFeature>(
VowpalWabbit vw,
VowpalWabbitSerializer <TExample> serializer,
VowpalWabbitSerializer <TActionDependentFeature> actionDependentFeatureSerializer,
TExample example,
IEnumerable <TActionDependentFeature> actionDependentFeatures)
{
Contract.Requires(vw != null);
Contract.Requires(serializer != null);
Contract.Requires(actionDependentFeatureSerializer != null);
Contract.Requires(example != null);
Contract.Requires(actionDependentFeatures != null);
// shared |userlda :.1 |che a:.1
// `doc1 |lda :.1 :.2 [1]
// `doc2 |lda :.2 :.3 [2]
// <new line>
var examples = new List <VowpalWabbitExample>();
try
{
// contains prediction results
var sharedExample = serializer.Serialize(vw, example);
// check if we have shared features
if (sharedExample != null)
{
examples.Add(sharedExample);
vw.Predict(sharedExample);
}
// leave as loop (vs. linq) so if the serializer throws an exception, anything allocated so far can be free'd
foreach (var actionDependentFeature in actionDependentFeatures)
{
var adfExample = actionDependentFeatureSerializer.Serialize(vw, actionDependentFeature);
Contract.Assert(adfExample != null);
examples.Add(adfExample);
vw.Predict(adfExample);
}
// signal we're finished using an empty example
var empty = vw.GetOrCreateEmptyExample();
examples.Add(empty);
vw.Predict(empty);
// Nasty workaround. Since the prediction result is stored in the first example
// and we'll have to get an actual VowpalWabbitExampt
var firstExample = examples.FirstOrDefault();
if (firstExample == null)
{
return(null);
}
return(firstExample.GetPrediction(vw, VowpalWabbitPredictionType.Multilabel));
}
finally
{
// dispose examples
// Note: must not dispose examples before final example
// as the learning algorithm (such as cbf) keeps a reference
// to the example
foreach (var e in examples)
{
e.Dispose();
}
}
}