Package org.apache.commons.math.distribution

Class PascalDistributionImpl

    • Constructor Detail

      • PascalDistributionImpl

        public PascalDistributionImpl​(int r,
                              double p)
        Create a Pascal distribution with the given number of trials and probability of success.
        Parameters:
        r - the number of successes
        p - the probability of success

    • Method Detail

      • getNumberOfSuccesses

        public int getNumberOfSuccesses()
        Access the number of successes for this distribution.
        Specified by:
        getNumberOfSuccesses in interface PascalDistribution
        Returns:
        the number of successes

      • getProbabilityOfSuccess

        public double getProbabilityOfSuccess()
        Access the probability of success for this distribution.
        Specified by:
        getProbabilityOfSuccess in interface PascalDistribution
        Returns:
        the probability of success

      • setNumberOfSuccesses

        @Deprecated
public void setNumberOfSuccesses​(int successes)
        Deprecated.
        as of 2.1 (class will become immutable in 3.0)
        Change the number of successes for this distribution.
        Specified by:
        setNumberOfSuccesses in interface PascalDistribution
        Parameters:
        successes - the new number of successes
        Throws:
        java.lang.IllegalArgumentException - if successes is not positive.

      • setProbabilityOfSuccess

        @Deprecated
public void setProbabilityOfSuccess​(double p)
        Deprecated.
        as of 2.1 (class will become immutable in 3.0)
        Change the probability of success for this distribution.
        Specified by:
        setProbabilityOfSuccess in interface PascalDistribution
        Parameters:
        p - the new probability of success
        Throws:
        java.lang.IllegalArgumentException - if p is not a valid probability.

      • getDomainLowerBound

        protected int getDomainLowerBound​(double p)
        Access the domain value lower bound, based on p, used to bracket a PDF root.
        Specified by:
        getDomainLowerBound in class AbstractIntegerDistribution
        Parameters:
        p - the desired probability for the critical value
        Returns:
        domain value lower bound, i.e. P(X < lower bound) < p

      • getDomainUpperBound

        protected int getDomainUpperBound​(double p)
        Access the domain value upper bound, based on p, used to bracket a PDF root.
        Specified by:
        getDomainUpperBound in class AbstractIntegerDistribution
        Parameters:
        p - the desired probability for the critical value
        Returns:
        domain value upper bound, i.e. P(X < upper bound) > p

      • probability

        public double probability​(int x)
        For this distribution, X, this method returns P(X = x).
        Specified by:
        probability in interface IntegerDistribution
        Parameters:
        x - the value at which the PMF is evaluated
        Returns:
        PMF for this distribution

      • inverseCumulativeProbability

        public int inverseCumulativeProbability​(double p)
                                 throws MathException
        For this distribution, X, this method returns the largest x, such that P(X ≤ x) ≤ p.

        Returns -1 for p=0 and Integer.MAX_VALUE for p=1.

        Specified by:
        inverseCumulativeProbability in interface IntegerDistribution
        Overrides:
        inverseCumulativeProbability in class AbstractIntegerDistribution
        Parameters:
        p - the desired probability
        Returns:
        the largest x such that P(X ≤ x) <= p
        Throws:
        MathException - if the inverse cumulative probability can not be computed due to convergence or other numerical errors.
        java.lang.IllegalArgumentException - if p < 0 or p > 1

      • getSupportLowerBound

        public int getSupportLowerBound()
        Returns the lower bound of the support for the distribution. The lower bound of the support is always 0 no matter the parameters.
        Returns:
        lower bound of the support (always 0)
        Since:
        2.2

      • getSupportUpperBound

        public int getSupportUpperBound()
        Returns the upper bound of the support for the distribution. The upper bound of the support is always positive infinity no matter the parameters. Positive infinity is represented by Integer.MAX_VALUE together with AbstractIntegerDistribution.isSupportUpperBoundInclusive() being false
        Returns:
        upper bound of the support (always Integer.MAX_VALUE for positive infinity)
        Since:
        2.2

      • getNumericalMean

        public double getNumericalMean()
        Returns the mean. For number of successes r and probability of success p, the mean is ( r * p ) / ( 1 - p )
        Returns:
        the mean
        Since:
        2.2

      • getNumericalVariance

        public double getNumericalVariance()
        Returns the variance. For number of successes r and probability of success p, the mean is ( r * p ) / ( 1 - p )^2
        Returns:
        the variance
        Since:
        2.2