CliqueFactory.java

/*
 * Ivory: A Hadoop toolkit for web-scale information retrieval
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you
 * may not use this file except in compliance with the License. You may
 * obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * permissions and limitations under the License.
 */

package ivory.smrf.model.builder;

import ivory.core.ConfigurationException;
import ivory.core.RetrievalEnvironment;
import ivory.core.util.XMLTools;
import ivory.smrf.model.Clique;
import ivory.smrf.model.DocumentNode;
import ivory.smrf.model.GraphNode;
import ivory.smrf.model.Parameter;
import ivory.smrf.model.TermNode;
import ivory.smrf.model.potential.PotentialFunction;

import java.util.ArrayList;
import java.util.List;

import org.w3c.dom.Node;

import com.google.common.collect.Lists;

/**
 * @author Don Metzler
 */
public class CliqueFactory {
  public static List<Clique> getSequentialDependenceCliques(RetrievalEnvironment env,
      String[] queryTerms, Node domNode, boolean docDependent) throws ConfigurationException {
    List<Clique> cliques = Lists.newArrayList();     // Clique set.
    DocumentNode docNode = new DocumentNode();       // The document node.

    // If there are no terms, then return an empty MRF.
    if (queryTerms.length == 0) {
      return cliques;
    }

    // Default parameter associated with CliqueSet.
    Parameter parameter = new Parameter(Parameter.DEFAULT, 1.0f);

    // Get potential type.
    String potentialType = XMLTools.getAttributeValueOrThrowException(domNode, "potential",
        "A potential attribute must be specified in order to generate a clique set!");

    // If there is more than one term, then add appropriate cliques.
    List<GraphNode> cliqueNodes = null;
    Clique c = null;
    TermNode lastTermNode = null;

    for (String element : queryTerms) {
      // Term node.
      TermNode termNode = new TermNode(element);

      // Add sequential cliques.
      if (lastTermNode != null) {
        cliqueNodes = Lists.newArrayList();
        if (docDependent) {
          cliqueNodes.add(docNode);
        }
        cliqueNodes.add(lastTermNode);
        cliqueNodes.add(termNode);

        // Get the potential function.
        PotentialFunction potential = PotentialFunction.create(env, potentialType, domNode);

        c = new Clique(cliqueNodes, potential, parameter);
        cliques.add(c);
      }

      // Update last term node.
      lastTermNode = termNode;
    }

    return cliques;
  }

  public static List<Clique> getFullDependenceCliques(RetrievalEnvironment env,
      String[] queryTerms, Node domNode, boolean ordered, boolean docDependent)
      throws ConfigurationException {
    List<Clique> cliques = Lists.newArrayList();     // Clique set.
    DocumentNode docNode = new DocumentNode();       // The document node.

    // If there are no terms, then return an empty MRF.
    if (queryTerms.length == 0) {
      return cliques;
    }

    // Default parameter associated with CliqueSet.
    Parameter parameter = new Parameter(Parameter.DEFAULT, 1.0f);

    // Get potential type.
    String potentialType = XMLTools.getAttributeValueOrThrowException(domNode, "potential",
        "A potential attribute must be specified in order to generate a clique set!");

    // If there is more than one term, then add appropriate cliques.
    ArrayList<GraphNode> cliqueNodes = null;
    Clique c = null;

    for (int i = 1; i < Math.pow(2, queryTerms.length); i++) {
      String binary = Integer.toBinaryString(i);
      int padding = queryTerms.length - binary.length();
      for (int j = 0; j < padding; j++) {
        binary = "0" + binary;
      }

      boolean singleTerm = false;
      boolean contiguous = true;

      int firstOne = binary.indexOf('1');
      int lastOne = binary.lastIndexOf('1');
      if (lastOne == firstOne) {
        singleTerm = true;
      }

      for (int j = binary.indexOf('1') + 1; j <= binary.lastIndexOf('1') - 1; j++) {
        if (binary.charAt(j) == '0') {
          contiguous = false;
          break;
        }
      }

      if (ordered && !singleTerm && contiguous) {
        cliqueNodes = Lists.newArrayList();
        if (docDependent) {
          cliqueNodes.add(docNode);
        }
        for (int j = firstOne; j <= lastOne; j++) {
          TermNode termNode = new TermNode(queryTerms[j]);
          cliqueNodes.add(termNode);
        }

        // Get the potential function.
        PotentialFunction potential = PotentialFunction.create(env, potentialType, domNode);

        c = new Clique(cliqueNodes, potential, parameter);
        cliques.add(c);
      } else if (!ordered && !singleTerm && !contiguous) {
        cliqueNodes = Lists.newArrayList();
        if (docDependent) {
          cliqueNodes.add(docNode);
        }
        for (int j = 0; j < binary.length(); j++) {
          if (binary.charAt(j) == '1') {
            TermNode termNode = new TermNode(queryTerms[j]);
            cliqueNodes.add(termNode);
          }
        }

        // Get the potential function.
        PotentialFunction potential = PotentialFunction.create(env, potentialType, domNode);

        c = new Clique(cliqueNodes, potential, parameter);
        cliques.add(c);
      }
    }

    return cliques;
  }
}