Decoding Strategies

Abstract Tagger

• Create a package cs325.tagger.
• Download the TagList class.
• Create an abstract class AbstractTagger.
• Create a constructor.
• @param classifier a multi-classifier.
• Define a method addSentence.
• Adds training instances from a sentences.
• @param words the words in the sentence.
• @param tags the pos-tags in the sentence.
• Define a method train.
• Calls the train method in the classifier.
• Define a protected method getFeatures.
• @return a list of string features from the current state.
• @param words the list of words.
• @param tags the list of previously found pos-tags.
• @param index the current index.
• Declare an abstract method decode.
• @return the list of tags with the overall probability.
• @param words the list of words.

Greedy, Exhaustive, Top, Beam Tagger

• Create classes GreedyTagger, ExhaustiveTagger, TopTagger, and BeamTagger.
• Override the decode methods using greedy, exhaustive, top, and beam decoding strategies.
• Reference: DSUtils.

Unit Test

• Test your decoding strategies using TaggerTest.

Quiz

• Complete the TopKTagger class such that it considers the top-k highest probable predictions at each state. Run your TopKTagger using TaggerTest, where k = 3. Submit your code and the results from TaggerTest.