edu.berkeley.nlp.ling.CollinsHeadFinder Maven / Gradle / Ivy
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package edu.berkeley.nlp.ling;
//import edu.berkeley.nlp.ling.CategoryWordTag;
import java.io.StringReader;
import java.util.List;
import java.util.HashMap;
import edu.berkeley.nlp.syntax.Tree;
import edu.berkeley.nlp.syntax.Trees;
import edu.berkeley.nlp.treebank.PennTreebankLanguagePack;
import edu.berkeley.nlp.treebank.TreebankLanguagePack;
/**
* Implements the HeadFinder found in Michael Collins' 1999 thesis. Except:
* we've added a head rule for NX, which returns the leftmost item. No rule for
* the head of NX is found in any of the versions of Collins' head table that we
* have (did he perhaps use the NP rules for NX? -- no Bikel, CL, 2005 says it
* defaults to leftmost). These rules are suitable for the Penn Treebank.
*
* May 2004: Added support for AUX and AUXG to the VP rules; these cause no
* interference in Penn Treebank parsing, but means that these rules also work
* for the BLLIP corpus (or Charniak parser output in general). Feb 2005: Fixes
* to coordination reheading so that punctuation cannot become head.
*
* @author Christopher Manning
*/
public class CollinsHeadFinder extends AbstractCollinsHeadFinder {
public CollinsHeadFinder() {
this(new PennTreebankLanguagePack());
}
protected int postOperationFix(int headIdx, List> daughterTrees) {
if (headIdx >= 2) {
String prevLab = daughterTrees.get(headIdx - 1).getLabel();
if (prevLab.equals("CC")) {
int newHeadIdx = headIdx - 2;
Tree t = daughterTrees.get(newHeadIdx);
while (newHeadIdx >= 0 && t.isPreTerminal()
&& tlp.isPunctuationTag(t.getLabel())) {
newHeadIdx--;
}
if (newHeadIdx >= 0) {
headIdx = newHeadIdx;
}
}
}
return headIdx;
}
@SuppressWarnings("unchecked")
public CollinsHeadFinder(TreebankLanguagePack tlp) {
super(tlp);
nonTerminalInfo = new HashMap();
// This version from Collins' diss (1999: 236-238)
nonTerminalInfo.put("ADJP", new String[][] { { "left", "NNS", "QP", "NN",
"$", "ADVP", "JJ", "VBN", "VBG", "ADJP", "JJR", "NP", "JJS", "DT",
"FW", "RBR", "RBS", "SBAR", "RB" } });
nonTerminalInfo.put("ADVP", new String[][] { { "right", "RB", "RBR", "RBS",
"FW", "ADVP", "TO", "CD", "JJR", "JJ", "IN", "NP", "JJS", "NN" } });
nonTerminalInfo.put("CONJP",
new String[][] { { "right", "CC", "RB", "IN" } });
nonTerminalInfo.put("FRAG", new String[][] { { "right" } }); // crap
nonTerminalInfo.put("INTJ", new String[][] { { "left" } });
nonTerminalInfo.put("LST", new String[][] { { "right", "LS", ":" } });
nonTerminalInfo.put("NAC", new String[][] { { "left", "NN", "NNS", "NNP",
"NNPS", "NP", "NAC", "EX", "$", "CD", "QP", "PRP", "VBG", "JJ", "JJS",
"JJR", "ADJP", "FW" } });
nonTerminalInfo.put("NX", new String[][] { { "left" } }); // crap
nonTerminalInfo.put("PP", new String[][] { { "right", "IN", "TO", "VBG",
"VBN", "RP", "FW" } });
// should prefer JJ? (PP (JJ such) (IN as) (NP (NN crocidolite)))
nonTerminalInfo.put("PRN", new String[][] { { "left" } });
nonTerminalInfo.put("PRT", new String[][] { { "right", "RP" } });
nonTerminalInfo.put("QP", new String[][] { { "left", "$", "IN", "NNS",
"NN", "JJ", "RB", "DT", "CD", "NCD", "QP", "JJR", "JJS" } });
nonTerminalInfo.put("RRC", new String[][] { { "right", "VP", "NP", "ADVP",
"ADJP", "PP" } });
nonTerminalInfo.put("S", new String[][] { { "left", "TO", "IN", "VP", "S",
"SBAR", "ADJP", "UCP", "NP" } });
nonTerminalInfo.put("SBAR", new String[][] { { "left", "WHNP", "WHPP",
"WHADVP", "WHADJP", "IN", "DT", "S", "SQ", "SINV", "SBAR", "FRAG" } });
nonTerminalInfo.put("SBARQ", new String[][] { { "left", "SQ", "S", "SINV",
"SBARQ", "FRAG" } });
nonTerminalInfo.put("SINV", new String[][] { { "left", "VBZ", "VBD", "VBP",
"VB", "MD", "VP", "S", "SINV", "ADJP", "NP" } });
nonTerminalInfo.put("SQ", new String[][] { { "left", "VBZ", "VBD", "VBP",
"VB", "MD", "VP", "SQ" } });
nonTerminalInfo.put("UCP", new String[][] { { "right" } });
nonTerminalInfo.put("VP", new String[][] { { "left", "TO", "VBD", "VBN",
"MD", "VBZ", "VB", "VBG", "VBP", "AUX", "AUXG", "VP", "ADJP", "NN",
"NNS", "NP" } });
nonTerminalInfo.put("WHADJP", new String[][] { { "left", "CC", "WRB", "JJ",
"ADJP" } });
nonTerminalInfo.put("WHADVP", new String[][] { { "right", "CC", "WRB" } });
nonTerminalInfo.put("WHNP", new String[][] { { "left", "WDT", "WP", "WP$",
"WHADJP", "WHPP", "WHNP" } });
nonTerminalInfo.put("WHPP",
new String[][] { { "right", "IN", "TO", "FW" } });
nonTerminalInfo.put("X", new String[][] { { "right" } }); // crap rule
nonTerminalInfo.put("NP", new String[][] {
{ "rightdis", "NN", "NNP", "NNPS", "NNS", "NX", "POS", "JJR" },
{ "left", "NP" }, { "rightdis", "$", "ADJP", "PRN" },
{ "right", "CD" }, { "rightdis", "JJ", "JJS", "RB", "QP" } });
nonTerminalInfo.put("TYPO", new String[][] { { "left" } }); // another crap
// rule, for
// Switchboard
// (Roger)
}
/**
* Go through trees and determine their heads and print them. Just for
* debuggin'.
* Usage:
* java edu.stanford.nlp.trees.CollinsHeadFinder treebankFilePath
*
*
* @param args
* The treebankFilePath
*/
public static void main(String[] args) {
Trees.PennTreeReader reader = new Trees.PennTreeReader(new StringReader("((S (NP (DT the) (JJ quick) (JJ (AA (BB (CC brown)))) (NN fox)) (VP (VBD jumped) (PP (IN over) (NP (DT the) (JJ lazy) (NN dog)))) (. .)))"));
Tree tree = reader.next();
System.out.println("tree "+tree);
CollinsHeadFinder headFinder = new CollinsHeadFinder();
while (!tree.isLeaf()) {
Tree head = headFinder.determineHead(tree);
System.out.println("head "+head);
tree=head;
}
}
private static final long serialVersionUID = -8747319554557223437L;
}