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// For information as to what this class does, see the Javadoc, below.       //
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// Scheines, Joseph Ramsey, and Clark Glymour.                               //
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package edu.cmu.tetrad.bayes;

import edu.cmu.tetrad.graph.Node;

import java.util.List;

/**
 * Interface containing methods to calculate probabilities for systems of
 * discrete variables. See instantiations for more details.
 *
 * @author josephramsey
 */
interface DiscreteProbs {

    /**
     * @return the variables over which probabilities and conditional
     * probabilities will be calculated.
     */
    List<Node> getVariables();

    /**
     * @return the probability in a given cell.
     */
    double getCellProb(int[] cell);

    /**
     * Calculates the probability P(a), where a is a two dimensional boolean
     * array, with a[i] representing particular combinations of values for
     * bayesIm.getNode(i) as boolean arrays of length bayesim.getNumSplits(i),
     * with a[i][j] = true iff the condition includes the j'th value of
     * bayesIm.getNode(i).
     */
    double getProb(Proposition assertion);

    /**
     * <p>Calculates the conditional probability P(a|b), where a and b are two
     * dimensional boolean arrays, with a[i] and b[i] representing particular
     * combinations of values for bayesIm.getNode(i) as boolean arrays of length
     * bayesim.getNumSplits(i), with a[i][j] = true iff the condition
     * includes the j'th value of bayesIm.getNode(i), and similarly for
     * b[i][j].&gt; 0 <p>This does not allow all possible conditional
     * probabilities to be calculated, since for instance the condition X1 = 1
     * or X2 = 2 cannot be represented this way directly, but it does capture
     * all conditions for which this type of method would generally be of
     * interest.&gt; 0
     */
    double getConditionalProb(Proposition assertion, Proposition condition);

}





