/// <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>
/// Simplify learning of examples with action dependent features.
/// </summary>
public static void Learn <TExample, TActionDependentFeature>(
VowpalWabbit vw,
VowpalWabbitSingleExampleSerializer <TExample> serializer,
VowpalWabbitSingleExampleSerializer <TActionDependentFeature> actionDependentFeatureSerializer,
TExample example,
IReadOnlyCollection <TActionDependentFeature> actionDependentFeatures,
int index,
ILabel label)
{
Contract.Requires(vw != null);
Contract.Requires(actionDependentFeatureSerializer != null);
Contract.Requires(example != null);
Contract.Requires(actionDependentFeatures != null);
Contract.Requires(index >= 0);
Contract.Requires(label != null);
Execute(
vw,
serializer,
actionDependentFeatureSerializer,
example,
actionDependentFeatures,
(examples, _, __) =>
{
vw.Learn(examples.ToList());
},
index,
label);
}
/// <summary>
/// Initializes a new instance of the <see cref="VowpalWabbit{TExample}"/> class.
/// </summary>
/// <param name="vw">The native instance to wrap.</param>
/// <remarks>This instance takes ownership of <paramref name="vw"/> instance and disposes it.</remarks>
public VowpalWabbit(VowpalWabbit vw)
{
if (vw == null)
{
throw new ArgumentNullException("vw");
}
Contract.Ensures(this.serializer != null);
Contract.EndContractBlock();
this.vw = vw;
this.compiledSerializer = VowpalWabbitSerializerFactory.CreateSerializer <TExample>(vw.Settings);
if (this.compiledSerializer == null)
{
throw new ArgumentException("No features found for " + typeof(TExample));
}
this.serializer = this.compiledSerializer.Create(vw);
// have a 2nd member to throw NullReferenceException in release instead of silently producing wrong results.
this.learnSerializer = this.serializer.CachesExamples ? null : this.serializer;
// have a 3rd member to avoid cast everytime...
this.singleLineSerializer = this.serializer as VowpalWabbitSingleExampleSerializer <TExample>;
}
/// <summary>
/// Simplify learning 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>[] LearnAndPredict <TExample, TActionDependentFeature>(
VowpalWabbit vw,
VowpalWabbitSingleExampleSerializer <TExample> serializer,
VowpalWabbitSingleExampleSerializer <TActionDependentFeature> actionDependentFeatureSerializer,
TExample example,
IReadOnlyCollection <TActionDependentFeature> actionDependentFeatures,
int index,
ILabel label)
{
Contract.Requires(vw != null);
Contract.Requires(actionDependentFeatureSerializer != null);
Contract.Requires(example != null);
Contract.Requires(actionDependentFeatures != null);
Contract.Requires(index >= 0);
Contract.Requires(label != null);
ActionDependentFeature <TActionDependentFeature>[] predictions = null;
Execute(
vw,
serializer,
actionDependentFeatureSerializer,
example,
actionDependentFeatures,
(examples, validActionDependentFeatures, emptyActionDependentFeatures) =>
{
foreach (var ex in examples)
{
vw.Learn(ex);
}
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>
/// Initializes a new instance of the <see cref="VowpalWabbit{TExample}"/> class.
/// </summary>
/// <param name="vw">The native instance to wrap.</param>
/// <param name="compiledSerializer">The per-compiled serializer.</param>
/// <remarks>This instance takes ownership of <paramref name="vw"/> instance and disposes it.</remarks>
public VowpalWabbit(VowpalWabbit vw, IVowpalWabbitSerializerCompiler <TExample> compiledSerializer)
{
if (vw == null)
{
throw new ArgumentNullException(nameof(vw));
}
if (compiledSerializer == null)
{
throw new ArgumentNullException(nameof(compiledSerializer));
}
Contract.Ensures(this.serializer != null);
Contract.EndContractBlock();
this.vw = vw;
this.compiledSerializer = compiledSerializer;
this.serializer = this.compiledSerializer.Create(vw);
// have a 2nd member to throw NullReferenceException in release instead of silently producing wrong results.
this.learnSerializer = this.serializer.CachesExamples ? null : this.serializer;
// have a 3rd member to avoid cast everytime...
this.singleLineSerializer = this.serializer as VowpalWabbitSingleExampleSerializer <TExample>;
}
/// <summary>
/// Simplify learning of examples with action dependent features.
/// </summary>
/// <typeparam name="TExample">User example type.</typeparam>
/// <typeparam name="TActionDependentFeature">Action dependent feature type.</typeparam>
/// <param name="vw">The VowpalWabbit instances.</param>
/// <param name="serializer">The example serializer.</param>
/// <param name="actionDependentFeatureSerializer">The action dependent feature serializer.</param>
/// <param name="example">The example.</param>
/// <param name="actionDependentFeatures">The action dependent features.</param>
/// <param name="predictOrLearn">An action executed once the set of valid examples is determined. </param>
/// <param name="index">The optional index of the action dependent feature this label belongs too.</param>
/// <param name="label">The optional label to be used for learning or evaluation.</param>
public static void Execute <TExample, TActionDependentFeature>(
VowpalWabbit vw,
VowpalWabbitSingleExampleSerializer <TExample> serializer,
VowpalWabbitSingleExampleSerializer <TActionDependentFeature> actionDependentFeatureSerializer,
TExample example,
IReadOnlyCollection <TActionDependentFeature> actionDependentFeatures,
LearnOrPredictAction <TActionDependentFeature> predictOrLearn,
int?index = null,
ILabel label = null)
{
Contract.Requires(vw != null);
Contract.Requires(actionDependentFeatureSerializer != null);
Contract.Requires(example != null);
Contract.Requires(actionDependentFeatures != null);
var examples = new List <VowpalWabbitExample>(actionDependentFeatures.Count + 1);
var validExamples = new List <VowpalWabbitExample>(actionDependentFeatures.Count + 1);
var validActionDependentFeatures = new List <ActionDependentFeature <TActionDependentFeature> >(actionDependentFeatures.Count + 1);
var emptyActionDependentFeatures = new List <ActionDependentFeature <TActionDependentFeature> >(actionDependentFeatures.Count + 1);
VowpalWabbitExample emptyExample = null;
try
{
// contains prediction results
if (serializer != null)
{
var sharedExample = serializer.Serialize(example, SharedLabel.Instance);
// check if we have shared features
if (sharedExample != null)
{
examples.Add(sharedExample);
if (!sharedExample.IsNewLine)
{
validExamples.Add(sharedExample);
}
}
}
var i = 0;
foreach (var actionDependentFeature in actionDependentFeatures)
{
var adfExample = actionDependentFeatureSerializer.Serialize(actionDependentFeature,
index != null && i == index ? label : null);
Contract.Assert(adfExample != null);
examples.Add(adfExample);
if (!adfExample.IsNewLine)
{
validExamples.Add(adfExample);
validActionDependentFeatures.Add(new ActionDependentFeature <TActionDependentFeature>(i, actionDependentFeature));
}
else
{
emptyActionDependentFeatures.Add(new ActionDependentFeature <TActionDependentFeature>(i, actionDependentFeature));
}
i++;
}
if (validActionDependentFeatures.Count == 0)
{
return;
}
// signal we're finished using an empty example
emptyExample = vw.GetOrCreateNativeExample();
emptyExample.MakeEmpty(vw);
predictOrLearn(validExamples, validActionDependentFeatures, emptyActionDependentFeatures);
}
finally
{
if (emptyExample != null)
{
emptyExample.Dispose();
}
// 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();
}
}
}
