/// <summary>
/// Adds the appropriate features for the token at the specified index with the
/// specified array of previous outcomes to the specified list of features.
/// </summary>
/// <param name="features">The list of features to be added to.</param>
/// <param name="tokens">The tokens of the sentence or other text unit being processed.</param>
/// <param name="index">The index of the token which is currently being processed.</param>
/// <param name="previousOutcomes">The outcomes for the tokens prior to the specified index.</param>
public void CreateFeatures(List <string> features, string[] tokens, int index, string[] previousOutcomes)
{
List <string> cacheFeatures;
if (tokens == prevTokens)
{
cacheFeatures = (List <string>)contextsCache.Get(index);
if (cacheFeatures != null)
{
NumberOfCacheHits++;
features.AddRange(cacheFeatures);
return;
}
}
else
{
contextsCache.Clear();
prevTokens = tokens;
}
cacheFeatures = new List <string>();
NumberOfCacheMisses++;
generator.CreateFeatures(cacheFeatures, tokens, index, previousOutcomes);
contextsCache.Put(index, cacheFeatures);
features.AddRange(cacheFeatures);
}
/// <summary>
/// Adds the appropriate features for the token at the specified index with the
/// specified array of previous outcomes to the specified list of features.
/// </summary>
/// <param name="features">The list of features to be added to.</param>
/// <param name="tokens">The tokens of the sentence or other text unit being processed.</param>
/// <param name="index">The index of the token which is currently being processed.</param>
/// <param name="previousOutcomes">The outcomes for the tokens prior to the specified index.</param>
public void CreateFeatures(List <string> features, string[] tokens, int index, string[] previousOutcomes)
{
generator.CreateFeatures(features, tokens, index, previousOutcomes);
// previous features
for (var i = 1; i < prevWindowSize + 1; i++)
{
if (index - i >= 0)
{
var prevFeatures = new List <string>();
generator.CreateFeatures(prevFeatures, tokens, index - i, previousOutcomes);
foreach (var prevFeature in prevFeatures)
{
features.Add(PREV_PREFIX + i + prevFeature);
}
}
}
// next features
for (var i = 1; i < nextWindowSize + 1; i++)
{
if (i + index < tokens.Length)
{
var nextFeatures = new List <string>();
generator.CreateFeatures(nextFeatures, tokens, index + i, previousOutcomes);
foreach (var nextFeature in nextFeatures)
{
features.Add(NEXT_PREFIX + i + nextFeature);
}
}
}
}