Java BayesNet类代码示例

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
JunctionTreeSeparator(Set<Integer> separator, BayesNet bayesNet,
  JunctionTreeNode childNode, JunctionTreeNode parentNode) {
  // ////////////////////
  // initialize node set
  m_nNodes = new int[separator.size()];
  int iPos = 0;
  m_nCardinality = 1;
  for (Integer element : separator) {
    int iNode = element;
    m_nNodes[iPos++] = iNode;
    m_nCardinality *= bayesNet.getCardinality(iNode);
  }
  m_parentNode = parentNode;
  m_childNode = childNode;
  m_bayesNet = bayesNet;
}
 

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
JunctionTreeNode(Set<Integer> clique, BayesNet bayesNet, boolean[] bDone) {
  m_bayesNet = bayesNet;
  m_children = new Vector<JunctionTreeNode>();
  // ////////////////////
  // initialize node set
  m_nNodes = new int[clique.size()];
  int iPos = 0;
  m_nCardinality = 1;
  for (Integer integer : clique) {
    int iNode = integer;
    m_nNodes[iPos++] = iNode;
    m_nCardinality *= bayesNet.getCardinality(iNode);
  }
  // //////////////////////////////
  // initialize potential function
  calculatePotentials(bayesNet, clique, bDone);
}
 

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
/**
 * initCPTs reserves space for CPTs and set all counts to zero
 * 
 * @param bayesNet the bayes net to use
 * @throws Exception if something goes wrong
 */
@Override
public void initCPTs(BayesNet bayesNet) throws Exception {
  // Reserve space for CPTs
  int nMaxParentCardinality = 1;

  for (int iAttribute = 0; iAttribute < bayesNet.m_Instances.numAttributes(); iAttribute++) {
    if (bayesNet.getParentSet(iAttribute).getCardinalityOfParents() > nMaxParentCardinality) {
      nMaxParentCardinality = bayesNet.getParentSet(iAttribute)
        .getCardinalityOfParents();
    }
  }

  // Reserve plenty of memory
  bayesNet.m_Distributions = new Estimator[bayesNet.m_Instances
    .numAttributes()][nMaxParentCardinality];
}
 

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
/**
 * Updates the classifier with the given instance.
 * 
 * @param bayesNet the bayes net to use
 * @param instance the new training instance to include in the model
 * @throws Exception if the instance could not be incorporated in the model.
 */
@Override
public void updateClassifier(BayesNet bayesNet, Instance instance)
  throws Exception {
  for (int iAttribute = 0; iAttribute < bayesNet.m_Instances.numAttributes(); iAttribute++) {
    double iCPT = 0;

    for (int iParent = 0; iParent < bayesNet.getParentSet(iAttribute)
      .getNrOfParents(); iParent++) {
      int nParent = bayesNet.getParentSet(iAttribute).getParent(iParent);

      iCPT = iCPT * bayesNet.m_Instances.attribute(nParent).numValues()
        + instance.value(nParent);
    }

    bayesNet.m_Distributions[iAttribute][(int) iCPT].addValue(
      instance.value(iAttribute), instance.weight());
  }
}
 

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
/**
 * initCPTs reserves space for CPTs and set all counts to zero
 * 
 * @param bayesNet the bayes net to use
 * @throws Exception if something goes wrong
 */
@Override
public void initCPTs(BayesNet bayesNet) throws Exception {
  Instances instances = bayesNet.m_Instances;

  // Reserve space for CPTs
  int nMaxParentCardinality = 1;
  for (int iAttribute = 0; iAttribute < instances.numAttributes(); iAttribute++) {
    if (bayesNet.getParentSet(iAttribute).getCardinalityOfParents() > nMaxParentCardinality) {
      nMaxParentCardinality = bayesNet.getParentSet(iAttribute)
        .getCardinalityOfParents();
    }
  }

  // Reserve plenty of memory
  bayesNet.m_Distributions = new Estimator[instances.numAttributes()][nMaxParentCardinality];

  // estimate CPTs
  for (int iAttribute = 0; iAttribute < instances.numAttributes(); iAttribute++) {
    for (int iParent = 0; iParent < bayesNet.getParentSet(iAttribute)
      .getCardinalityOfParents(); iParent++) {
      bayesNet.m_Distributions[iAttribute][iParent] = new DiscreteEstimatorBayes(
        instances.attribute(iAttribute).numValues(), m_fAlpha);
    }
  }
}
 

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
/**
 * search determines the network structure/graph of the network with the Taby
 * algorithm.
 * 
 * @param bayesNet the network to use
 * @param instances the data to use
 * @throws Exception if something goes wrong
 */
@Override
protected void search(BayesNet bayesNet, Instances instances)
  throws Exception {
  initCache(bayesNet, instances);

  // go do the search
  Operation oOperation = getOptimalOperation(bayesNet, instances);
  while ((oOperation != null) && (oOperation.m_fDeltaScore > 0)) {
    performOperation(bayesNet, instances, oOperation);
    oOperation = getOptimalOperation(bayesNet, instances);
  }

  // free up memory
  m_Cache = null;
}
 

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
/**
 * getOptimalOperation finds the optimal operation that can be performed on
 * the Bayes network that is not in the tabu list.
 * 
 * @param bayesNet Bayes network to apply operation on
 * @param instances data set to learn from
 * @return optimal operation found
 * @throws Exception if something goes wrong
 */
Operation getOptimalOperation(BayesNet bayesNet, Instances instances)
  throws Exception {
  Operation oBestOperation = new Operation();

  // Add???
  oBestOperation = findBestArcToAdd(bayesNet, instances, oBestOperation);
  // Delete???
  oBestOperation = findBestArcToDelete(bayesNet, instances, oBestOperation);
  // Reverse???
  if (getUseArcReversal()) {
    oBestOperation = findBestArcToReverse(bayesNet, instances, oBestOperation);
  }

  // did we find something?
  if (oBestOperation.m_fDeltaScore == -1E100) {
    return null;
  }

  return oBestOperation;
}
 

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
/**
 * find best (or least bad) arc addition operation
 * 
 * @param bayesNet Bayes network to add arc to
 * @param instances data set
 * @param oBestOperation
 * @return Operation containing best arc to add, or null if no arc addition is
 *         allowed (this can happen if any arc addition introduces a cycle, or
 *         all parent sets are filled up to the maximum nr of parents).
 */
Operation findBestArcToAdd(BayesNet bayesNet, Instances instances,
  Operation oBestOperation) {
  int nNrOfAtts = instances.numAttributes();
  // find best arc to add
  for (int iAttributeHead = 0; iAttributeHead < nNrOfAtts; iAttributeHead++) {
    if (bayesNet.getParentSet(iAttributeHead).getNrOfParents() < m_nMaxNrOfParents) {
      for (int iAttributeTail = 0; iAttributeTail < nNrOfAtts; iAttributeTail++) {
        if (addArcMakesSense(bayesNet, instances, iAttributeHead,
          iAttributeTail)) {
          Operation oOperation = new Operation(iAttributeTail,
            iAttributeHead, Operation.OPERATION_ADD);
          if (m_Cache.get(oOperation) > oBestOperation.m_fDeltaScore) {
            if (isNotTabu(oOperation)) {
              oBestOperation = oOperation;
              oBestOperation.m_fDeltaScore = m_Cache.get(oOperation);
            }
          }
        }
      }
    }
  }
  return oBestOperation;
}
 

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
/**
 * find best (or least bad) arc deletion operation
 * 
 * @param bayesNet Bayes network to delete arc from
 * @param instances data set
 * @param oBestOperation
 * @return Operation containing best arc to delete, or null if no deletion can
 *         be made (happens when there is no arc in the network yet).
 */
Operation findBestArcToDelete(BayesNet bayesNet, Instances instances,
  Operation oBestOperation) {
  int nNrOfAtts = instances.numAttributes();
  // find best arc to delete
  for (int iNode = 0; iNode < nNrOfAtts; iNode++) {
    ParentSet parentSet = bayesNet.getParentSet(iNode);
    for (int iParent = 0; iParent < parentSet.getNrOfParents(); iParent++) {
      Operation oOperation = new Operation(parentSet.getParent(iParent),
        iNode, Operation.OPERATION_DEL);
      if (m_Cache.get(oOperation) > oBestOperation.m_fDeltaScore) {
        if (isNotTabu(oOperation)) {
          oBestOperation = oOperation;
          oBestOperation.m_fDeltaScore = m_Cache.get(oOperation);
        }
      }
    }
  }
  return oBestOperation;
}
 

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
/**
 * find best (or least bad) arc reversal operation
 * 
 * @param bayesNet Bayes network to reverse arc in
 * @param instances data set
 * @param oBestOperation
 * @return Operation containing best arc to reverse, or null if no reversal is
 *         allowed (happens if there is no arc in the network yet, or when any
 *         such reversal introduces a cycle).
 */
Operation findBestArcToReverse(BayesNet bayesNet, Instances instances,
  Operation oBestOperation) {
  int nNrOfAtts = instances.numAttributes();
  // find best arc to reverse
  for (int iNode = 0; iNode < nNrOfAtts; iNode++) {
    ParentSet parentSet = bayesNet.getParentSet(iNode);
    for (int iParent = 0; iParent < parentSet.getNrOfParents(); iParent++) {
      int iTail = parentSet.getParent(iParent);
      // is reversal allowed?
      if (reverseArcMakesSense(bayesNet, instances, iNode, iTail)
        && bayesNet.getParentSet(iTail).getNrOfParents() < m_nMaxNrOfParents) {
        // go check if reversal results in the best step forward
        Operation oOperation = new Operation(parentSet.getParent(iParent),
          iNode, Operation.OPERATION_REVERSE);
        if (m_Cache.get(oOperation) > oBestOperation.m_fDeltaScore) {
          if (isNotTabu(oOperation)) {
            oBestOperation = oOperation;
            oBestOperation.m_fDeltaScore = m_Cache.get(oOperation);
          }
        }
      }
    }
  }
  return oBestOperation;
}
 

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
/**
 * getOptimalOperation finds the optimal operation that can be performed on
 * the Bayes network that is not in the tabu list.
 * 
 * @param bayesNet Bayes network to apply operation on
 * @param instances data set to learn from
 * @return optimal operation found
 * @throws Exception if something goes wrong
 */
Operation getOptimalOperation(BayesNet bayesNet, Instances instances)
  throws Exception {
  Operation oBestOperation = new Operation();

  // Add???
  oBestOperation = findBestArcToAdd(bayesNet, instances, oBestOperation);
  // Delete???
  oBestOperation = findBestArcToDelete(bayesNet, instances, oBestOperation);
  // Reverse???
  if (getUseArcReversal()) {
    oBestOperation = findBestArcToReverse(bayesNet, instances, oBestOperation);
  }

  // did we find something?
  if (oBestOperation.m_fScore == -1E100) {
    return null;
  }

  return oBestOperation;
}
 

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
/**
 * find best (or least bad) arc addition operation
 * 
 * @param bayesNet Bayes network to add arc to
 * @param instances data set
 * @param oBestOperation
 * @return Operation containing best arc to add, or null if no arc addition is
 *         allowed (this can happen if any arc addition introduces a cycle, or
 *         all parent sets are filled up to the maximum nr of parents).
 * @throws Exception if something goes wrong
 */
Operation findBestArcToAdd(BayesNet bayesNet, Instances instances,
  Operation oBestOperation) throws Exception {
  int nNrOfAtts = instances.numAttributes();
  // find best arc to add
  for (int iAttributeHead = 0; iAttributeHead < nNrOfAtts; iAttributeHead++) {
    if (bayesNet.getParentSet(iAttributeHead).getNrOfParents() < m_nMaxNrOfParents) {
      for (int iAttributeTail = 0; iAttributeTail < nNrOfAtts; iAttributeTail++) {
        if (addArcMakesSense(bayesNet, instances, iAttributeHead,
          iAttributeTail)) {
          Operation oOperation = new Operation(iAttributeTail,
            iAttributeHead, Operation.OPERATION_ADD);
          double fScore = calcScoreWithExtraParent(oOperation.m_nHead,
            oOperation.m_nTail);
          if (fScore > oBestOperation.m_fScore) {
            if (isNotTabu(oOperation)) {
              oBestOperation = oOperation;
              oBestOperation.m_fScore = fScore;
            }
          }
        }
      }
    }
  }
  return oBestOperation;
}
 

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
/**
 * find best (or least bad) arc deletion operation
 * 
 * @param bayesNet Bayes network to delete arc from
 * @param instances data set
 * @param oBestOperation
 * @return Operation containing best arc to delete, or null if no deletion can
 *         be made (happens when there is no arc in the network yet).
 * @throws Exception of something goes wrong
 */
Operation findBestArcToDelete(BayesNet bayesNet, Instances instances,
  Operation oBestOperation) throws Exception {
  int nNrOfAtts = instances.numAttributes();
  // find best arc to delete
  for (int iNode = 0; iNode < nNrOfAtts; iNode++) {
    ParentSet parentSet = bayesNet.getParentSet(iNode);
    for (int iParent = 0; iParent < parentSet.getNrOfParents(); iParent++) {
      Operation oOperation = new Operation(parentSet.getParent(iParent),
        iNode, Operation.OPERATION_DEL);
      double fScore = calcScoreWithMissingParent(oOperation.m_nHead,
        oOperation.m_nTail);
      if (fScore > oBestOperation.m_fScore) {
        if (isNotTabu(oOperation)) {
          oBestOperation = oOperation;
          oBestOperation.m_fScore = fScore;
        }
      }
    }
  }
  return oBestOperation;
}
 

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
/**
 * LeaveOneOutCV returns the accuracy calculated using Leave One Out cross
 * validation. The dataset used is m_Instances associated with the Bayes
 * Network.
 * 
 * @param bayesNet : Bayes Network containing structure to evaluate
 * @return accuracy (in interval 0..1) measured using leave one out cv.
 * @throws Exception passed on by updateClassifier
 */
public double leaveOneOutCV(BayesNet bayesNet) throws Exception {
  m_BayesNet = bayesNet;
  double fAccuracy = 0.0;
  double fWeight = 0.0;
  Instances instances = bayesNet.m_Instances;
  bayesNet.estimateCPTs();
  for (int iInstance = 0; iInstance < instances.numInstances(); iInstance++) {
    Instance instance = instances.instance(iInstance);
    instance.setWeight(-instance.weight());
    bayesNet.updateClassifier(instance);
    fAccuracy += accuracyIncrease(instance);
    fWeight += instance.weight();
    instance.setWeight(-instance.weight());
    bayesNet.updateClassifier(instance);
  }
  return fAccuracy / fWeight;
}
 

import weka.classifiers.bayes.BayesNet; //导入依赖的package包/类
/**
 * Count nr of arcs missing from other network compared to current network
 * Note that an arc is not 'missing' if it is reversed.
 * 
 * @param other network to compare with
 * @return nr of missing arcs
 */
public int missingArcs(BayesNet other) {
  try {
    Sync(other);
    int nMissing = 0;
    for (int iAttribute = 0; iAttribute < m_Instances.numAttributes(); iAttribute++) {
      for (int iParent = 0; iParent < m_ParentSets[iAttribute]
        .getNrOfParents(); iParent++) {
        int nParent = m_ParentSets[iAttribute].getParent(iParent);
        if (!other.getParentSet(m_order[iAttribute]).contains(
          m_order[nParent])
          && !other.getParentSet(m_order[nParent]).contains(
            m_order[iAttribute])) {
          nMissing++;
        }
      }
    }
    return nMissing;
  } catch (Exception e) {
    System.err.println(e.getMessage());
    return 0;
  }
}