Example usage for org.apache.commons.math3.exception.util LocalizedFormats FACTORIAL_NEGATIVE_PARAMETER

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Prototype

LocalizedFormats FACTORIAL_NEGATIVE_PARAMETER

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Usage

From source file:org.gitools.analysis.groupcomparison.format.math33Preview.CombinatoricsUtils.java

/**
 * Returns n!. Shorthand for {@code n} <a
 * href="http://mathworld.wolfram.com/Factorial.html"> Factorial</a>, the
 * product of the numbers {@code 1, ..., n}.
 * <p>/*  w  w  w  .j  a  v a2  s.  c  om*/
 * <Strong>Preconditions</strong>:
 * <ul>
 * <li> {@code n >= 0} (otherwise
 * {@code IllegalArgumentException} is thrown)</li>
 * <li> The result is small enough to fit into a {@code long}. The
 * largest value of {@code n} for which {@code n!} <
 * Long.MAX_VALUE} is 20. If the computed value exceeds {@code Long.MAX_VALUE}
 * an {@code ArithMeticException } is thrown.</li>
 * </ul>
 * </p>
 *
 * @param n argument
 * @return {@code n!}
 * @throws MathArithmeticException if the result is too large to be represented
 *                                 by a {@code long}.
 * @throws NotPositiveException    if {@code n < 0}.
 * @throws MathArithmeticException if {@code n > 20}: The factorial value is too
 *                                 large to fit in a {@code long}.
 */
public static long factorial(final int n) throws NotPositiveException, MathArithmeticException {
    if (n < 0) {
        throw new NotPositiveException(LocalizedFormats.FACTORIAL_NEGATIVE_PARAMETER, n);
    }
    if (n > 20) {
        throw new MathArithmeticException();
    }
    return FACTORIALS[n];
}

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From source file:org.gitools.analysis.groupcomparison.format.math33Preview.CombinatoricsUtils.java

/**
 * Compute n!, the<a href="http://mathworld.wolfram.com/Factorial.html">
 * factorial</a> of {@code n} (the product of the numbers 1 to n), as a
 * {@code double}.// w w  w. j  a va 2s.  com
 * The result should be small enough to fit into a {@code double}: The
 * largest {@code n} for which {@code n! < Double.MAX_VALUE} is 170.
 * If the computed value exceeds {@code Double.MAX_VALUE},
 * {@code Double.POSITIVE_INFINITY} is returned.
 *
 * @param n Argument.
 * @return {@code n!}
 * @throws NotPositiveException if {@code n < 0}.
 */
public static double factorialDouble(final int n) throws NotPositiveException {
    if (n < 0) {
        throw new NotPositiveException(LocalizedFormats.FACTORIAL_NEGATIVE_PARAMETER, n);
    }
    if (n < 21) {
        return FACTORIALS[n];
    }
    return FastMath.floor(FastMath.exp(CombinatoricsUtils.factorialLog(n)) + 0.5);
}

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From source file:org.gitools.analysis.groupcomparison.format.math33Preview.CombinatoricsUtils.java

/**
 * Compute the natural logarithm of the factorial of {@code n}.
 *
 * @param n Argument./*  www  . j  a  v  a  2s  .c om*/
 * @return {@code n!}
 * @throws NotPositiveException if {@code n < 0}.
 */
public static double factorialLog(final int n) throws NotPositiveException {
    if (n < 0) {
        throw new NotPositiveException(LocalizedFormats.FACTORIAL_NEGATIVE_PARAMETER, n);
    }
    if (n < 21) {
        return FastMath.log(FACTORIALS[n]);
    }
    double logSum = 0;
    for (int i = 2; i <= n; i++) {
        logSum += FastMath.log(i);
    }
    return logSum;
}

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