Natural Language Processors
Java Scala Other
Latest commit cc48ac8 Feb 24, 2017 @hickst hickst committed on GitHub Merge pull request #141 from clulab/json4s
json4s version bump

README.md

Build Status

What is it?

This is the main public code repository of the Computational Language Understanding (CLU) Lab led by Mihai Surdeanu at University of Arizona. This repository contains (in descending order of novelty):

  • A rule-based event extraction (EE) framework called Odin (Open Domain INformer) in the org.clulab.odin package. See Odin's Wiki page for more details.
  • Two full-fledged Rhetorical Structure Theory (RST) discourse parsers. The discourse parsers are transparently included in our natural language (NL) processors (see below). The version in CoreNLPProcessor relies on constituent syntax, whereas the one in FastNLPProcessor uses dependency syntax. The latter is marginally worse (< 1 F1 point lower for the complete task) but it is much faster. You can test our discourse parsers online here.
  • A machine learning (ML) package (org.clulab.learning), which includes implementations for common ML algorithms (e.g., Perceptron, Logistic Regression, Support Vector Machines, Random Forests) for both classification and ranking.
  • A suite of NL processors in the org.clulab.processors package. We currently provide three APIs: one for Stanford's CoreNLP, one for a faster processor (FastNLPProcessor) that cherry picks fast components from multiple sources (Stanford and MaltParser), and, lastly, one for biomedical texts (BioNLPProcessor), which integrates resources trained for this domain (Stanford parser and our own NER based on the Stanford CRF).

This software requires Java 1.8, Scala 2.11, and CoreNLP 3.x or higher.

Our code is licensed as follows:

  • main, models - Apache License Version 2.0. Please note that these subprojects do not interact with the corenlp subproject below.
  • corenlp - GLP Version 3 or higher, due to the dependency on Stanford's CoreNLP.

(c) Mihai Surdeanu, 2013 -

Authors: Mihai Surdeanu, Marco Valenzuela, Gustave Hahn-Powell, Peter Jansen, Daniel Fried, Dane Bell, and Tom Hicks.

Changes

  • 6.0.2 - Enhance NER to load multiple override files.
  • 6.0.2 - file I/O fix related to json deserialization.
  • 6.0.2 - Fixed odin bug related to^ in lookbehinds. Update to use Bioresources 1.1.19 containing Bioentities project KBs.
  • 6.0.1 - Added support to odin for redefining variables.
  • 6.0.1 - Added support to odin for matching mention arguments.
  • 6.0.1 - Added support to odin for cross-sentence patterns.
  • 6.0.1 - Fixed odin bug when matching overlapping entities with same end at the beginning of a pattern.
  • 6.0.1 - Improved validation of named entities in RuleNER.
  • 6.0.1 - Added automated lexical variations to the BioNLPProcessor RuleNER.
  • 6.0.1 - Bug fix in multi-world entity matching in the RuleNER.
  • 6.0.0 - Reorganization into 3 subprojects with different licenses: main, corenlp, models.
  • 6.0.0 - Optimizations to json serialization/deserialization.
  • 5.9.6 - Serialize/deserialize Document, Mention, etc. to/from json.
  • 5.9.5 - Bug fix release: do not tag XML tags such as XREF... as named entities.
  • more...

Citations

If you use one of our discourse parsers, please cite this paper:

Mihai Surdeanu, Thomas Hicks, and Marco A. Valenzuela-Escarcega. Two Practical Rhetorical Structure Theory Parsers. In Proceedings of the Conference of the North American Chapter of the Association for Computational Linguistics - Human Language Technologies: Software Demonstrations (NAACL HLT), 2015. [pdf] [bib]

If you use Odin, our event extraction framework, please cite this paper:

Marco A. Valenzuela-Escarcega, Gustave Hahn-Powell, Thomas Hicks, and Mihai Surdeanu. A Domain-independent Rule-based Framework for Event Extraction. In Proceedings of the 53rd Annual Meeting of the Association for Computational Linguistics and the 7th International Joint Conference on Natural Language Processing of the Asian Federation of Natural Language Processing: Software Demonstrations (ACL-IJCNLP), 2015. [pdf] [bib]

If you use CoreNLPProcessor, please cite Stanford's paper:

Christopher D. Manning, Mihai Surdeanu, John Bauer, Jenny Finkel, Steven J. Bethard, and David McClosky. The Stanford CoreNLP Natural Language Processing Toolkit. In Proceedings of the 52nd Annual Meeting of the Association for Computational Linguistics (ACL), 2014. [pdf] [bib]

If you use anything else in this package, please link to this github page.

Installation

This software is available on Maven Central. To use, simply add the following dependencies to your pom.xml:

<dependency>
   <groupId>org.clulab</groupId>
   <artifactId>processors-corenlp_2.11</artifactId>
   <version>6.0.2</version>
</dependency>
<dependency>
   <groupId>org.clulab</groupId>
   <artifactId>processors-main_2.11</artifactId>
   <version>6.0.2</version>
</dependency>
<dependency>
   <groupId>org.clulab</groupId>
   <artifactId>processors-models_2.11</artifactId>
   <version>6.0.2</version>
</dependency>

The equivalent SBT dependencies are:

libraryDependencies ++= Seq(
    "org.clulab" %% "processors-corenlp" % "6.0.2",
    "org.clulab" %% "processors-main" % "6.0.2",
    "org.clulab" %% "processors-models" % "6.0.2"
)

External Dependencies

Most of the processors dependencies are captured in the build file. However, a few processors unit tests depend also on svm-rank, which should be installed separately. Simply installing the svm-rank binaries to /usr/local/bin (or another generic location on your OS) solves the problem:

https://www.cs.cornell.edu/people/tj/svm_light/svm_rank.html

Installing external dependencies on Mac OS X via homebrew

brew tap myedibleenso/nlp/svmlight
brew tap myedibleenso/nlp/svmrank
brew install svmlight svmrank

Skipping tests involving external dependencies

Alternatively, you can run just the unit tests that do not require external binaries with the following command:

sbt 'test-only -- -l NeedsExternalBinary'

Why you should use this code

  • Simple API - the APIs provided are, at least in my opinion, simpler than those provided for the original code. For example, when using CoreNLP you won't have to deal with hash maps that take class objects as keys. Instead, we use mostly arrays of integers or strings, which are self explanatory.
  • Memory efficient - arrays are more memory efficient than hash maps. Furthermore, we used our own implementation to intern strings (i.e., avoiding the storage of duplicated strings multiple times). Due to these changes, I measured up to 99% decrease in memory for the annotations corresponding to a typical natural language text, when compared to the original CoreNLP code. (Note: this reduction takes effect only after CoreNLP finishes its work.)
  • Faster access - again, because we use arrays instead of hash maps, access to the NL annotations (once constructed) is considerably faster than in the original Stanford code.
  • Tool-independent API - we support multiple NL and machine learning tools. If you use this code, you will have to change your code only minimally (i.e., only the constructor for the Processor object).
  • Discourse parsing - we include a complete RST parser; simply instantiate CoreNLPProcessor with withDiscourse = true.
  • Biomedical tools - we now include tools to process biomedical texts, which can be used under the same simple interface. We also offer event extraction tools for the biomedical domain.
  • Rule-based event extraction - we include Odin, an event extraction framework, which can be customized to various domains.

How to compile the source code

This is a standard sbt project, so use the usual commands, e.g., sbt compile, sbt assembly, to compile. Add the generated jar files under target/ to your $CLASSPATH, along with the other necessary dependency jars. Take a look at build.sbt to see which dependencies are necessary at runtime.

How to use it

Common scenarios

Most of the examples here use Scala. However, this software can be used as is from Java as well! Scroll down towards the end of this document to see a Java usage example.

Annotating entire documents

(see corenlp/src/main/scala/org/clulab/processors/examples/ProcessorExample.scala for a complete running example)

import org.clulab.processors.corenlp.CoreNLPProcessor
import org.clulab.processors.shallownlp.ShallowNLPProcessor
import org.clulab.processors.{Document, Processor}
import org.clulab.struct.DirectedGraphEdgeIterator

// create the processor
// any processor works here! Try FastNLPProcessor or BioNLPProcessor.
// use no arguments in the c'tor if you don't need the discourse parser
val proc:Processor = new CoreNLPProcessor(ShallowNLPProcessor.WITH_DISCOURSE) 

// the actual work is done here
val doc = proc.annotate("John Smith went to China. He visited Beijing, on January 10th, 2013.")

// you are basically done. the rest of this code simply prints out the annotations

// let's print the sentence-level annotations
var sentenceCount = 0
for (sentence <- doc.sentences) {
  println("Sentence #" + sentenceCount + ":")
  println("Tokens: " + sentence.words.mkString(" "))
  println("Start character offsets: " + sentence.startOffsets.mkString(" "))
  println("End character offsets: " + sentence.endOffsets.mkString(" "))

  // these annotations are optional, so they are stored using Option objects, hence the foreach statement
  sentence.lemmas.foreach(lemmas => println(s"Lemmas: ${lemmas.mkString(" ")}"))
  sentence.tags.foreach(tags => println(s"POS tags: ${tags.mkString(" ")}"))
  sentence.chunks.foreach(chunks => println(s"Chunks: ${chunks.mkString(" ")}"))
  sentence.entities.foreach(entities => println(s"Named entities: ${entities.mkString(" ")}"))
  sentence.norms.foreach(norms => println(s"Normalized entities: ${norms.mkString(" ")}"))
  sentence.dependencies.foreach(dependencies => {
    println("Syntactic dependencies:")
    val iterator = new DirectedGraphEdgeIterator[String](dependencies)
    while(iterator.hasNext) {
      val dep = iterator.next
      // note that we use offsets starting at 0 (unlike CoreNLP, which uses offsets starting at 1)
      println(" head:" + dep._1 + " modifier:" + dep._2 + " label:" + dep._3)
    }
  })
  sentence.syntacticTree.foreach(tree => {
    println("Constituent tree: " + tree)
    // see the org.clulab.utils.Tree class for more information
    // on syntactic trees, including access to head phrases/words
  })

  sentenceCount += 1
  println("\n")
}

// let's print the coreference chains
doc.coreferenceChains.foreach(chains => {
  for (chain <- chains.getChains) {
    println("Found one coreference chain containing the following mentions:")
    for (mention <- chain) {
      // note that all these offsets start at 0 too
      println("\tsentenceIndex:" + mention.sentenceIndex +
        " headIndex:" + mention.headIndex +
        " startTokenOffset:" + mention.startOffset +
        " endTokenOffset:" + mention.endOffset +
        " text: " + doc.sentences(mention.sentenceIndex).words.slice(mention.startOffset, mention.endOffset).mkString("[", " ", "]"))
    }
  }
})

// let's print the discourse tree
doc.discourseTree.foreach(dt => {
  println("Document-wide discourse tree:")
  println(dt.toString())
})

The above code generates the following output:

Sentence #0:
Tokens: John Smith went to China .
Start character offsets: 0 5 11 16 19 24
End character offsets: 4 10 15 18 24 25
Lemmas: John Smith go to China .
POS tags: NNP NNP VBD TO NNP .
Chunks: B-NP I-NP B-VP B-PP B-NP O
Named entities: PERSON PERSON O O LOCATION O
Normalized entities: O O O O O O
Syntactic dependencies:
  head:1 modifier:0 label:nn
  head:2 modifier:1 label:nsubj
  head:2 modifier:4 label:prep_to
Constituent tree: (ROOT (S (NP (NNP John) (NNP Smith)) (VP (VBD went) (PP (TO to) (NP (NNP China)))) (. .)))


Sentence #1:
Tokens: He visited Beijing , on January 10th , 2013 .
Start character offsets: 26 29 37 44 46 49 57 61 63 67
End character offsets: 28 36 44 45 48 56 61 62 67 68
Lemmas: he visit Beijing , on January 10th , 2013 .
POS tags: PRP VBD NNP , IN NNP JJ , CD .
Chunks: B-NP B-VP B-NP O B-PP B-NP I-NP I-NP I-NP O
Named entities: O O LOCATION O O DATE DATE DATE DATE O
Normalized entities: O O O O O 2013-01-10 2013-01-10 2013-01-10 2013-01-10 O
Syntactic dependencies:
  head:1 modifier:0 label:nsubj
  head:1 modifier:2 label:dobj
  head:1 modifier:8 label:tmod
  head:2 modifier:5 label:prep_on
  head:5 modifier:6 label:amod
Constituent tree: (ROOT (S (NP (PRP He)) (VP (VBD visited) (NP (NP (NNP Beijing)) (, ,) (PP (IN on) (NP (NNP January) (JJ 10th))) (, ,)) (NP-TMP (CD 2013))) (. .)))


Found one coreference chain containing the following mentions:
  sentenceIndex:1 headIndex:2 startTokenOffset:2 endTokenOffset:3 text: [Beijing]
Found one coreference chain containing the following mentions:
  sentenceIndex:1 headIndex:0 startTokenOffset:0 endTokenOffset:1 text: [He]
  sentenceIndex:0 headIndex:1 startTokenOffset:0 endTokenOffset:2 text: [John Smith]
Found one coreference chain containing the following mentions:
  sentenceIndex:1 headIndex:5 startTokenOffset:5 endTokenOffset:9 text: [January 10th , 2013]
Found one coreference chain containing the following mentions:
  sentenceIndex:0 headIndex:4 startTokenOffset:4 endTokenOffset:5 text: [China]

Document-wide discourse tree:
elaboration (LeftToRight)
  TEXT:John Smith went to China .
  TEXT:He visited Beijing , on January 10th , 2013 .

For more details about the annotation data structures, please see the org/clulab/processor/Document.scala file.

Changing processors is trivial: just replace the first line in the above example with:

val proc:Processor = new FastNLPProcessor()
// everything else stays the same

FastNLPProcessor uses the Stanford tokenizer, POS tagger, and NER, but replaces its parser with maltparser, trained to generated Stanford "basic" (rather than "collapsed") dependencies. This means that this annotator does not produce constituent trees and coreference chains. However, because of the faster parser, you should see a speedup increase of at least one order of magnitude. The output of the above code with FastNLPProcessor is:

Sentence #0:
Tokens: John Smith went to China .
Start character offsets: 0 5 11 16 19 24
End character offsets: 4 10 15 18 24 25
Lemmas: John Smith go to China .
POS tags: NNP NNP VBD TO NNP .
Chunks: B-NP I-NP B-VP B-PP B-NP O
Named entities: PERSON PERSON O O LOCATION O
Normalized entities: O O O O O O
Syntactic dependencies:
 head:1 modifier:0 label:nn
 head:2 modifier:1 label:nsubj
 head:2 modifier:3 label:prep
 head:2 modifier:5 label:punct
 head:3 modifier:4 label:pobj


Sentence #1:
Tokens: He visited Beijing , on January 10th , 2013 .
Start character offsets: 26 29 37 44 46 49 57 61 63 67
End character offsets: 28 36 44 45 48 56 61 62 67 68
Lemmas: he visit Beijing , on January 10th , 2013 .
POS tags: PRP VBD NNP , IN NNP JJ , CD .
Chunks: B-NP B-VP B-NP O B-PP B-NP I-NP I-NP I-NP O
Named entities: O O LOCATION O O DATE DATE DATE DATE O
Normalized entities: O O O O O 2013-01-10 2013-01-10 2013-01-10 2013-01-10 O
Syntactic dependencies:
 head:1 modifier:0 label:nsubj
 head:1 modifier:2 label:dobj
 head:1 modifier:3 label:punct
 head:1 modifier:4 label:prep
 head:1 modifier:9 label:punct
 head:4 modifier:5 label:pobj
 head:5 modifier:6 label:amod
 head:5 modifier:7 label:punct
 head:5 modifier:8 label:num

Annotating documents already split into sentences

val doc = proc.annotateFromSentences(List("John Smith went to China.", "He visited Beijing."))
// everything else stays the same

Annotating documents already split into sentences and tokenized

val doc = annotateFromTokens(List(
  List("John", "Smith", "went", "to", "China", "."),
  List("There", ",", "he", "visited", "Beijing", ".")))
// everything else stays the same

Using individual annotators

You can of course use only some of the annotators provided by CoreNLP by calling them individually. To illustrate, the Processor.annotate() method is implemented as follows:

def annotate(doc:Document): Document = {
  tagPartsOfSpeech(doc)
  lemmatize(doc)
  recognizeNamedEntities(doc)
  parse(doc)
  chunking(doc)
  labelSemanticRoles(doc)
  resolveCoreference(doc)
  discourse(doc)
  doc.clear()
  doc
}

(Note that CoreNLP currently does not support semantic role labeling.) You can use just a few of these annotators. For example, if you need just POS tags, lemmas and named entities, you could use the following code:

val doc = proc.mkDocument("John Smith went to China. He visited Beijing, on January 10th, 2013.")
proc.tagPartsOfSpeech(doc)
proc.lemmatize(doc)
proc.recognizeNamedEntities(doc)
doc.clear()

Note that the last method called (doc.clear()) clears the internal structures created by the actual CoreNLP annotators. This saves a lot of memory, so, although it is not strictly necessary, I recommend you call it.

Serialization

This package also offers serialization code for the generated annotations. The two scenarios currently supported are:

Serialization to/from streams

// saving to a PrintWriter, pw
val someAnnotation = proc.annotate(someText)
val serializer = new DocumentSerializer
serializer.save(someAnnotation, pw)

// loading from an BufferedReader, br
val someAnnotation = serializer.load(br)

Serialization to/from Strings

// saving to a String object, savedString
val someAnnotation = proc.annotate(someText)
val serializer = new DocumentSerializer
val savedString = serializer.save(someAnnotation)

// loading from a String object, fromString
val someAnnotation = serializer.load(fromString)

Note that space required for these serialized annotations is considerably smaller (8 to 10 times) than the corresponding serialized Java objects. This is because we store only the information required to recreate these annotations (e.g., words, lemmas, etc.) without storing any of the Java/Scala objects and classes.

Serialization to/from json

As of v5.9.6, Document and Mention instances can be serialized to/from json (see the complete working example).

Cleaning up the interned strings

Classes that implement the Processor trait intern String objects to avoid allocating memory repeatedly for the same string. This is implemented by maintaining an internal dictionary of strings previously seen. This dictionary is unlikely to use a lot of memory due to the Zipfian distribution of language. But, if memory usage is a big concern, it can be cleaned by calling:

Processor.in.clear()

I recommend you do this only after you annotated all the documents you plan to keep in memory.

Although I see no good reason for doing this, you can disable the interning of strings completely by setting the internStrings = false in the CoreNLProcessor constructor, as such:

val processor = new CoreNLPProcessor(internStrings = false)

Using processors from Java

Scala is (largely) compatible with Java, so this library can be directly used from Java. Below is Java code that translates most of the functionality from the first Scala example in this document to Java:

package org.clulab.processors;


import org.clulab.discourse.rstparser.DiscourseTree;
import org.clulab.processors.fastnlp.FastNLPProcessor;
import org.clulab.processors.corenlp.CoreNLPProcessor;
import org.clulab.struct.CorefMention;
import org.clulab.struct.DirectedGraphEdgeIterator;

public class ProcessorsJavaExample {
    public static void main(String [] args) throws Exception {
        // create the processor
        Processor proc = new CoreNLPProcessor(true, false, 0, 100);
        // for much faster processing, use FastNLPProcessor
        // Processor proc = new FastNLPProcessor(true, false);

        // the actual work is done here
        Document doc = proc.annotate("John Smith went to China. He visited Beijing, on January 10th, 2013.", false);

        // you are basically done. the rest of this code simply prints out the annotations

        // let's print the sentence-level annotations
        int sentenceCount = 0;
        for (Sentence sentence: doc.sentences()) {
            System.out.println("Sentence #" + sentenceCount + ":");
            System.out.println("Tokens: " + mkString(sentence.words(), " "));
            System.out.println("Start character offsets: " + mkString(sentence.startOffsets(), " "));
            System.out.println("End character offsets: " + mkString(sentence.endOffsets(), " "));

            // these annotations are optional, so they are stored using Option objects, hence the isDefined checks
            if(sentence.lemmas().isDefined()){
                System.out.println("Lemmas: " + mkString(sentence.lemmas().get(), " "));
            }
            if(sentence.tags().isDefined()){
                System.out.println("POS tags: " + mkString(sentence.tags().get(), " "));
            }
            if(sentence.chunks().isDefined()){
                System.out.println("Chunks: " + mkString(sentence.chunks().get(), " "));
            }
            if(sentence.entities().isDefined()){
                System.out.println("Named entities: " + mkString(sentence.entities().get(), " "));
            }
            if(sentence.norms().isDefined()){
                System.out.println("Normalized entities: " + mkString(sentence.norms().get(), " "));
            }
            if(sentence.dependencies().isDefined()) {
                System.out.println("Syntactic dependencies:");
                DirectedGraphEdgeIterator<String> iterator = new
                    DirectedGraphEdgeIterator<String>(sentence.dependencies().get());
                while(iterator.hasNext()) {
                    scala.Tuple3<Object, Object, String> dep = iterator.next();
                    // note that we use offsets starting at 0 (unlike CoreNLP, which uses offsets starting at 1)
                    System.out.println(" head:" + dep._1() + " modifier:" + dep._2() + " label:" + dep._3());
                }
            }
            if(sentence.syntacticTree().isDefined()) {
                System.out.println("Constituent tree: " + sentence.syntacticTree().get());
                // see the org.clulab.struct.Tree class for more information
                // on syntactic trees, including access to head phrases/words
            }

            sentenceCount += 1;
            System.out.println("\n");
        }

        // let's print the coreference chains
        if(doc.coreferenceChains().isDefined()) {
            // these are scala.collection Iterator and Iterable (not Java!)
            scala.collection.Iterator<scala.collection.Iterable<CorefMention>> chains = doc.coreferenceChains().get().getChains().iterator();
            while(chains.hasNext()) {
                scala.collection.Iterator<CorefMention> chain = chains.next().iterator();
                System.out.println("Found one coreference chain containing the following mentions:");
                while(chain.hasNext()) {
                    CorefMention mention = chain.next();
                    // note that all these offsets start at 0 too
                    System.out.println("\tsentenceIndex:" + mention.sentenceIndex() +
                        " headIndex:" + mention.headIndex() +
                        " startTokenOffset:" + mention.startOffset() +
                        " endTokenOffset:" + mention.endOffset());
                }
            }
        }

        // let's print the discourse tree
        if(doc.discourseTree().isDefined()) {
            DiscourseTree tree = doc.discourseTree().get();
            System.out.println("Discourse tree:\n" + tree);
        }
    }

    public static String mkString(String [] sa, String sep) {
        StringBuilder os = new StringBuilder();
        for(int i = 0; i < sa.length; i ++) {
            if(i > 0) os.append(sep);
            os.append(sa[i]);
        }
        return os.toString();
    }
    public static String mkString(int [] sa, String sep) {
        StringBuilder os = new StringBuilder();
        for(int i = 0; i < sa.length; i ++) {
            if(i > 0) os.append(sep);
            os.append(Integer.toString(sa[i]));
        }
        return os.toString();
    }
}

The output of this code is:

Sentence #0:
Tokens: John Smith went to China .
Start character offsets: 0 5 11 16 19 24
End character offsets: 4 10 15 18 24 25
Lemmas: John Smith go to China .
POS tags: NNP NNP VBD TO NNP .
Chunks: B-NP I-NP B-VP B-PP B-NP O
Named entities: PERSON PERSON O O LOCATION O
Normalized entities: O O O O O O
Syntactic dependencies:
 head:1 modifier:0 label:nn
 head:2 modifier:1 label:nsubj
 head:2 modifier:4 label:prep_to
Constituent tree:
(ROOT
    (S
        (NP
            (NNP John)
            (NNP Smith)
        )
        (VP
            (VBD went)
            (PP
                (TO to)
                (NP
                    (NNP China)
                )
            )
        )
        (. .)
    )
)


Sentence #1:
Tokens: He visited Beijing , on January 10th , 2013 .
Start character offsets: 26 29 37 44 46 49 57 61 63 67
End character offsets: 28 36 44 45 48 56 61 62 67 68
Lemmas: he visit Beijing , on January 10th , 2013 .
POS tags: PRP VBD NNP , IN NNP JJ , CD .
Chunks: B-NP B-VP B-NP O B-PP B-NP I-NP I-NP I-NP O
Named entities: O O LOCATION O O DATE DATE DATE DATE O
Normalized entities: O O O O O 2013-01-10 2013-01-10 2013-01-10 2013-01-10 O
Syntactic dependencies:
 head:1 modifier:0 label:nsubj
 head:1 modifier:2 label:dobj
 head:1 modifier:8 label:tmod
 head:2 modifier:5 label:prep_on
 head:5 modifier:6 label:amod
Constituent tree:
(ROOT
    (S
        (NP
            (PRP He)
        )
        (VP
            (VBD visited)
            (NP
                (NP
                    (NNP Beijing)
                )
                (, ,)
                (PP
                    (IN on)
                    (NP
                        (NNP January)
                        (JJ 10th)
                    )
                )
                (, ,)
            )
            (NP-TMP
                (CD 2013)
            )
        )
        (. .)
    )
)


Found one coreference chain containing the following mentions:
    sentenceIndex:1 headIndex:2 startTokenOffset:2 endTokenOffset:7
Found one coreference chain containing the following mentions:
    sentenceIndex:0 headIndex:1 startTokenOffset:0 endTokenOffset:2
    sentenceIndex:1 headIndex:0 startTokenOffset:0 endTokenOffset:1
Found one coreference chain containing the following mentions:
    sentenceIndex:1 headIndex:5 startTokenOffset:5 endTokenOffset:7
Found one coreference chain containing the following mentions:
    sentenceIndex:0 headIndex:4 startTokenOffset:4 endTokenOffset:5
Found one coreference chain containing the following mentions:
    sentenceIndex:1 headIndex:8 startTokenOffset:8 endTokenOffset:9
Discourse tree:
elaboration (LeftToRight)
    TEXT:John Smith went to China .
    TEXT:He visited Beijing , on January 10th , 2013 .

The discourse parser

The discourse parser in processors is inspired by the parser of Feng and Hirst and the HILDA parser of Hernault et al., but with a different feature set. It is transparently integrated in both CoreNLPProcessor and FastNLPProcessor: just instantiate it as CoreNLPProcessor(withDiscourse = true) or FastNLPProcessor(withDiscourse = true). If discourse is enabled, Document.discourseTree stores the discourse tree for the entire document as an instance of the DiscourseTree class.

Following the conventions from other modern discourse parsing work, the discourse tree:

  • Is represented as a binary tree, containing hypotactic relations (containing one nucleus and one satellite node) or paratactic relations (both nodes have equal importance).
  • Stores the relation labels in the parent node (in DiscourseTree.relationLabel) rather than the satellite nodes (like the RST corpus). We use the same 18 labels as Feng and Hirst.
  • Stores the relation direction in DiscourseTree.relationDirection. The direction can be LeftToRight (meaning the nucleus is the left child), RightToLeft (the right node is the nucleus), or None (for paratactic relations).

If you end up using this discourse parser, I would appreciate it if you cited this work:

Peter Jansen, Mihai Surdeanu, and Peter Clark. Discourse Complements Lexical Semantics for Non-factoid Answer Reranking. In Proceedings of the 52nd Annual Meeting of the Association for Computational Linguistics (ACL), 2014. [bib]

Developers only: For more details on the discourse parsers, please see this Wiki page.

The org.clulab.learning package

processors now contains a machine learning (ML) package (org.clulab.learning), which includes implementations for common ML algorithms (e.g., Perceptron, Logistic Regression, Support Vector Machines, Random Forests) for both classification and ranking.

The structure of this package is heavily inspired by Stanford's CoreNLP. Similar to CoreNLP, we use a Datum trait to store a single data point, which is implemented by BVFDatum to store binary-valued-feature datums, or by RVFDatum to store real-valued-feature datums. A collection of data points is stored as a Dataset, which is similarly implemented by BVFDataset or RVFDataset. All classifiers implement the Classifier trait, which has three main methods: train, which trains a model a given dataset, classOf, which returns the most likely prediction for a given datum, and scoresOf, which returns the scores for all known labels for a given datum. We currently support the following classifiers: large-margin Perceptron (PerceptronClassifier), linear SVMs and logistic regression from liblinear (LibLinearClassifier), dual SVMs from libsvm (LibSVMClassifier), and random forests from fast-random-forest (RandomForestClassifier).

A similar structure exists for ranking problems, with RankingDataset used to store a corpus of ranking examples, and RankingClassifier as the API to be implemented by all ranking classifiers. We currently support the following classifiers: ranking Perceptron (PerceptronRankingClassifier), ranking SVMs from svm-rank (SVMRankingClassifier), and boosted decision trees from jforests (JForestsRankingClassifier).

For usage examples, including how to create datums and datasets from scratch or import them from the svm-light format, please take a look at the examples under src/test/scala/org/clulab/learning.

The Odin event extraction framework

Please see Odin's Wiki page for details.

Other resources