Stanford NN dependency parser: Unrecoverable error while loading a tagger model

Question

I am trying to test the new Stanford Dependency parser which works with Neural Networks. I am trying to run the demos which are included in the zip file. The files ParserDemo.java and ParserDemo2.java work fine. However the file DependencyParserDemo.java :

import edu.stanford.nlp.ling.HasWord;
import edu.stanford.nlp.ling.TaggedWord;
import edu.stanford.nlp.parser.nndep.DependencyParser;
import edu.stanford.nlp.process.DocumentPreprocessor;
import edu.stanford.nlp.tagger.maxent.MaxentTagger;
import edu.stanford.nlp.trees.GrammaticalStructure;

import java.io.StringReader;
import java.util.List;

/**
 * Demonstrates how to first use the tagger, then use the NN dependency
 * parser. Note that the parser will not work on untagged text.
 *
 * @author Jon Gauthier
 */
public class DependencyParserDemo {
  public static void main(String[] args) {
    String modelPath = DependencyParser.DEFAULT_MODEL;
    String taggerPath = "edu/stanford/nlp/models/pos-tagger/english-left3words/english-left3words-distsim.tagger";

    for (int argIndex = 0; argIndex < args.length; ) {
      switch (args[argIndex]) {
        case "-tagger":
          taggerPath = args[argIndex + 1];
          argIndex += 2;
          break;
        case "-model":
          modelPath = args[argIndex + 1];
          argIndex += 2;
          break;
        default:
          throw new RuntimeException("Unknown argument " + args[argIndex]);
      }
    }

    String text = "I can almost always tell when movies use fake dinosaurs.";

    MaxentTagger tagger = new MaxentTagger(taggerPath);
    DependencyParser parser = DependencyParser.loadFromModelFile(modelPath);

    DocumentPreprocessor tokenizer = new DocumentPreprocessor(new StringReader(text));
    for (List<HasWord> sentence : tokenizer) {
      List<TaggedWord> tagged = tagger.tagSentence(sentence);
      GrammaticalStructure gs = parser.predict(tagged);

      // Print typed dependencies
      System.err.println(gs);
    }
  }
}

Throws an error:

Exception in thread "main" edu.stanford.nlp.io.RuntimeIOException: Unrecoverable error while loading a tagger model
    at edu.stanford.nlp.tagger.maxent.MaxentTagger.readModelAndInit(MaxentTagger.java:769)
    at edu.stanford.nlp.tagger.maxent.MaxentTagger.<init>(MaxentTagger.java:297)
    at edu.stanford.nlp.tagger.maxent.MaxentTagger.<init>(MaxentTagger.java:262)
    at DependencyParserDemo.main(DependencyParserDemo.java:40)
Caused by: java.io.IOException: Unable to resolve "edu/stanford/nlp/models/pos-tagger/english-left3words/english-left3words-distsim.tagger" as either class path, filename or URL
    at edu.stanford.nlp.io.IOUtils.getInputStreamFromURLOrClasspathOrFileSystem(IOUtils.java:448)
    at edu.stanford.nlp.tagger.maxent.MaxentTagger.readModelAndInit(MaxentTagger.java:764)
    ... 3 more

Could someone tell me what am I doing wrong?

Answer 1

It seems like your path to the file "english-left3words-distsim.tagger" is not correct. Check if path you provide is correct. You can also try it with absolute path.

Belphegor replied:

I solved it with absolute path. I first created the following folders in the src folders: edu/stanford/nlp/models/pos-tagger/english-left3words/ and inside I pasted the file english-left3words-distsim.tagger (which is in the POS-tagger file stanford-postagger-full-2015-04-20.zip). After this - it worked.