/**
* Trains a boundary POS prioritization model (AKA a figure-of-merit, or FOM). Parses the training
* corpus, constrained by the gold trees, and learns prioritization probabilities from the
* resulting parses.
*
* @param sparseMatrixGrammar
* @return a boundary POS figure of merit model.
*/
protected BoundaryPosModel trainPosFom(final LeftCscSparseMatrixGrammar sparseMatrixGrammar) {
try {
// Constrained parse the training corpus
final ParserDriver opts = new ParserDriver();
opts.cellSelectorModel = ConstrainedCellSelector.MODEL;
opts.researchParserType = ResearchParserType.ConstrainedCartesianProductHashMl;
final ConstrainedCphSpmlParser constrainedParser =
new ConstrainedCphSpmlParser(opts, sparseMatrixGrammar);
final StringWriter binaryConstrainedParses = new StringWriter(30 * 1024 * 1024);
for (final String inputTree : trainingCorpus) {
final ParseTask parseTask = constrainedParser.parseSentence(inputTree);
binaryConstrainedParses.write(parseTask.binaryParse.toString());
binaryConstrainedParses.write('\n');
}
final StringWriter serializedFomModel = new StringWriter(30 * 1024 * 1024);
BoundaryPosModel.train(
sparseMatrixGrammar,
new BufferedReader(new StringReader(binaryConstrainedParses.toString())),
new BufferedWriter(serializedFomModel),
.5f,
false,
2);
final BufferedReader fomModelReader =
new BufferedReader(new StringReader(serializedFomModel.toString()));
return new BoundaryPosModel(FOMType.BoundaryPOS, sparseMatrixGrammar, fomModelReader);
} catch (final IOException e) {
// StringWriter and StringReader should never IOException
throw new AssertionError(e);
}
}
/**
* Parses the development set with the specified grammar and FOM. Returns the accuracy (F1) of the
* resulting parses. Uses the specified <code>beamWidth</code> for all cells spanning >= 2 words.
* For lexical cells, uses <code>beamWidth</code> x 3 (since the FOM does not prioritize entries
* in lexical cells), and allocates <code>beamWidth</code> entries in lexical cells for unary
* productions.
*
* @param sparseMatrixGrammar
* @param posFom
* @param cycle
* @return Accuracy (F1) and speed (w/s)
*/
protected float[] parseDevSet(
final LeftCscSparseMatrixGrammar sparseMatrixGrammar,
final BoundaryPosModel posFom,
final int cycle) {
// Initialize the parser
final ParserDriver opts = new ParserDriver();
opts.researchParserType = ResearchParserType.CartesianProductHashMl;
opts.cellSelectorModel = ccModel;
opts.fomModel = posFom;
// Set beam-width configuration properties
GlobalConfigProperties.singleton()
.setProperty(Parser.PROPERTY_MAX_BEAM_WIDTH, Integer.toString(beamWidth));
GlobalConfigProperties.singleton()
.setProperty(Parser.PROPERTY_LEXICAL_ROW_BEAM_WIDTH, Integer.toString(beamWidth * 3));
GlobalConfigProperties.singleton()
.setProperty(Parser.PROPERTY_LEXICAL_ROW_UNARIES, Integer.toString(beamWidth));
// Parse the dev-set
final CartesianProductHashSpmlParser parser =
new CartesianProductHashSpmlParser(opts, sparseMatrixGrammar);
final long t0 = System.currentTimeMillis();
int words = 0;
final BracketEvaluator evaluator = new BracketEvaluator();
for (final String inputTree : developmentSet) {
parser.parseSentence(inputTree).evaluate(evaluator);
final NaryTree<String> naryTree = NaryTree.read(inputTree, String.class);
words += naryTree.leaves();
}
final long t1 = System.currentTimeMillis();
return new float[] {(float) evaluator.accumulatedResult().f1(), words * 1000f / (t1 - t0)};
}
