Returns the natural log of the ( Binomial Coefficient : Math Functions « Development « Java Tutorial


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public class Main {

   * Returns the natural <code>log</code> of the <a
   * href=""> Binomial
   * Coefficient</a>, "<code>n choose k</code>", the number of
   * <code>k</code>-element subsets that can be selected from an
   * <code>n</code>-element set.
   * <Strong>Preconditions</strong>:
   * <ul>
   * <li> <code>0 <= k <= n </code> (otherwise
   * <code>IllegalArgumentException</code> is thrown)</li>
   * </ul>
   * @param n the size of the set
   * @param k the size of the subsets to be counted
   * @return <code>n choose k</code>
   * @throws IllegalArgumentException if preconditions are not met.
  public static double binomialCoefficientLog(final int n, final int k) {
      if (n < k) {
          throw new IllegalArgumentException(
              "must have n >= k for binomial coefficient (n,k)");
      if (n < 0) {
          throw new IllegalArgumentException(
              "must have n >= 0 for binomial coefficient (n,k)");
      if ((n == k) || (k == 0)) {
          return 0;
      if ((k == 1) || (k == n - 1)) {
          return Math.log((double)n);
      double logSum = 0;

      // n!/k!
      for (int i = k + 1; i <= n; i++) {
          logSum += Math.log((double)i);

      // divide by (n-k)!
      for (int i = 2; i <= n - k; i++) {
          logSum -= Math.log((double)i);

      return logSum;

6.17.Math Functions
6.17.1.Math Class Methods
6.17.2.Use math functions
6.17.3.Testing the Math class methods
6.17.4.Floating Point Number Enhancements in JDK 6
6.17.10.Demonstrate toDegrees() and toRadians().
6.17.11.Find absolute value of float, int, double and long using Math.abs
6.17.12.Find ceiling value of a number using Math.ceil
6.17.13.Find exponential value of a number using Math.exp
6.17.14.Find floor value of a number using Math.floor
6.17.15.Find maximum of two numbers using Math.max
6.17.16.Find natural logarithm value of a number using Math.log
6.17.17.Find power using Math.pow
6.17.18.Find square root of a number using Math.sqrt
6.17.19.Round Java float and double numbers using Math.round
6.17.21.Normalizes an angle to a relative angle.
6.17.22.Normalizes an angle to an absolute angle.
6.17.23.Normalizes an angle to be near an absolute angle
6.17.24.Calculate the floor of the log, base 2
6.17.25.Greatest Common Divisor (GCD) of positive integer numbers
6.17.26.Least Common Multiple (LCM) of two strictly positive integer numbers
6.17.27.Moving Average
6.17.28.Normalize an angle in a 2&pi wide interval around a center value.
6.17.29.Returns n!. Shorthand for n Factorial, the product of the numbers 1,...,n as a double.
6.17.30.Returns n!. Shorthand for n Factorial, the product of the numbers 1,...,n.
6.17.31.Returns the hyperbolic cosine of x.
6.17.32.Returns the hyperbolic sine of x.
6.17.33.Returns the natural log of the ( Binomial Coefficient
6.17.34.Returns the natural logarithm of n!.
6.17.35.Round the given value to the specified number of decimal places. The value is rounded using the BigDecimal.ROUND_HALF_UP method.
6.17.36.Value is rounded using the given method which is any method defined in BigDecimal
6.17.37.sqrt(a^2 + b^2) without under/overflow