Package edu.cmu.tetrad.bayes

Class ApproximateUpdater

java.lang.Object
edu.cmu.tetrad.bayes.ApproximateUpdater
All Implemented Interfaces:
BayesUpdater, ManipulatingBayesUpdater, TetradSerializable, Serializable
public final class ApproximateUpdater extends Object implements ManipulatingBayesUpdater
Calculates updated marginals for a Bayes net by simulating data and calculating likelihood ratios. The method is as follows. For P(A | B), enough sample points are simulated from the underlying BayesIm so that 1000 satisfy the condition B. Then the maximum likelihood estimate of condition A is calculated.
Author:
josephramsey
See Also:

  • Constructor Details

    • ApproximateUpdater

      public ApproximateUpdater(BayesIm bayesIm)
      Constructs a new updater for the given Bayes net.
      Parameters:
      bayesIm - the Bayes net to be updated.

    • ApproximateUpdater

      public ApproximateUpdater(BayesIm bayesIm, Evidence evidence)
      Constructs a new updater for the given Bayes net.
      Parameters:
      bayesIm - the Bayes net to be updated.
      evidence - the evidence for the update.

  • Method Details

    • serializableInstance

      public static ApproximateUpdater serializableInstance()
      Returns a simple exemplar of this class to test serialization.
      Returns:
      a simple exemplar of this class to test serialization.

    • getBayesIm

      public BayesIm getBayesIm()
      Description copied from interface: BayesUpdater
      Returns the evidence for the updater.
      Specified by:
      getBayesIm in interface BayesUpdater
      Returns:
      the Bayes instantiated model that is being updated.

    • getManipulatedBayesIm

      public BayesIm getManipulatedBayesIm()
      Description copied from interface: ManipulatingBayesUpdater
      Returns the manipulated Bayes IM. This is the Bayes IM in which the variables in the manipulation have been removed from the graph.
      Specified by:
      getManipulatedBayesIm in interface ManipulatingBayesUpdater
      Returns:
      the Bayes instantiated model after manipulations have been applied.

    • getManipulatedGraph

      public Graph getManipulatedGraph()
      Description copied from interface: ManipulatingBayesUpdater
      Returns the manipulated graph. This is the graph in which the variables in the manipulation have been removed from the graph.
      Specified by:
      getManipulatedGraph in interface ManipulatingBayesUpdater
      Returns:
      the graph for getManipulatedBayesIm().

    • getUpdatedBayesIm

      public BayesIm getUpdatedBayesIm()
      Description copied from interface: ManipulatingBayesUpdater
      Returns the updated Bayes IM. This is the Bayes IM in which all probabilities of variables conditional on their parents have been updated.
      Specified by:
      getUpdatedBayesIm in interface ManipulatingBayesUpdater
      Returns:
      the updated Bayes IM, or null if there is no updated Bayes IM.

    • getEvidence

      public Evidence getEvidence()
      Description copied from interface: ManipulatingBayesUpdater
      Returns the manipulation that was used to manipulate the Bayes IM.
      Specified by:
      getEvidence in interface ManipulatingBayesUpdater
      Returns:
      a copy of the getModel evidence.

    • setEvidence

      public void setEvidence(Evidence evidence)
      Sets new evidence for the next update operation.
      Specified by:
      setEvidence in interface BayesUpdater
      Specified by:
      setEvidence in interface ManipulatingBayesUpdater
      Parameters:
      evidence - the new evidence.

    • getMarginal

      public double getMarginal(int variable, int value)
      Description copied from interface: ManipulatingBayesUpdater
      Returns the updated graph. This is the graph in which all probabilities of variables conditional on their parents have been updated.
      Specified by:
      getMarginal in interface BayesUpdater
      Specified by:
      getMarginal in interface ManipulatingBayesUpdater
      Parameters:
      variable - variable index
      value - category index
      Returns:
      P(variable = category | evidence) where evidence is getEvidence().

    • isJointMarginalSupported

      public boolean isJointMarginalSupported()
      Description copied from interface: BayesUpdater
      Returns the joint marginal probability of the given variables taking the given values, given the evidence.
      Specified by:
      isJointMarginalSupported in interface BayesUpdater
      Returns:
      true if the getJointMarginal() method is supported.

    • getJointMarginal

      public double getJointMarginal(int[] variables, int[] values)
      Description copied from interface: BayesUpdater
      Returns the joint marginal probability of the given variables taking the given values, given the evidence.
      Specified by:
      getJointMarginal in interface BayesUpdater
      Parameters:
      variables - variable indices
      values - category indices
      Returns:
      the joint marginal.

    • calculatePriorMarginals

      public double[] calculatePriorMarginals(int nodeIndex)
      Description copied from interface: BayesUpdater
      Calculates the prior marginal probabilities of the given node.
      Specified by:
      calculatePriorMarginals in interface BayesUpdater
      Parameters:
      nodeIndex - node index
      Returns:
      P(node = value), where value is the value of the node in the Bayes net.

    • calculateUpdatedMarginals

      public double[] calculateUpdatedMarginals(int nodeIndex)
      Description copied from interface: BayesUpdater
      Calculates the updated marginal probabilities of the given node, given the evidence.
      Specified by:
      calculateUpdatedMarginals in interface BayesUpdater
      Parameters:
      nodeIndex - node index
      Returns:
      P(node = value | evidence), where value is the value of the node in the Bayes net.

    • toString

      public String toString()
      Prints out the most recent marginal.
      Overrides:
      toString in class Object