Package jahuwaldt.js.math

Class BinomialCoef

  • All Implemented Interfaces:
    SizedObject, javolution.lang.Immutable, javolution.lang.ValueType
    public final class BinomialCoef
extends java.lang.Object
implements javolution.lang.ValueType, SizedObject

    This class represents an immutable matrix of binomial coefficients (n/k) defined up to a specified maximum index. 

         ( n )      n!
     (   ) = --------   0 <= k <= n
     ( k )   k!(n-k)!

    Reference: http://en.wikipedia.org/wiki/Binomial_coefficient

    Modified by: Joseph A. Huwaldt

    Version:
    October 16, 2015
    Author:
    Joseph A. Huwaldt, Date: May 11, 2011

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      BinomialCoef copy()
      Returns a copy of this binomial coefficient matrix allocated by the calling thread (possibly on the stack).
      double get​(int n, int k)
      Return the specified binomial coefficient (n / k)
      static BinomialCoef newInstance​(int size)
      Returns a BinomialCoef instance holding the coefficients (at least) up to the specified size.
      static void recycle​(BinomialCoef instance)
      Recycles a BinomialCoef instance immediately (on the stack when executing in a StackContext).
      int size()
      Return the size of the binomial coefficient matrix (the maximum binomial index value: (N/N)).
      javolution.text.Text toText()
      Returns the text representation of this binomial coefficient matrix.

      • Methods inherited from class java.lang.Object

        equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Method Detail

      • newInstance

        public static BinomialCoef newInstance​(int size)
        Returns a BinomialCoef instance holding the coefficients (at least) up to the specified size. The returned instance may be recycled and may contain more coefficients than the requested size.
        Parameters:
        size - the desired size to compute coefficients for: N = size - 1 ==> (N/N) or size = N + 1.
        Returns:
        The binomial coefficient matrix having at least specified size.

      • size

        public int size()
        Return the size of the binomial coefficient matrix (the maximum binomial index value: (N/N)).
        Specified by:
        size in interface SizedObject

      • get

        public double get​(int n,
                  int k)
        Return the specified binomial coefficient (n / k)
        Parameters:
        n - The 1st index into the binomial coefficient matrix (n / k). Must be < size().
        k - The 2nd index into the binomial coefficient matrix (n / k). Must be < size().
        Returns:
        The specified binomial coefficient as a double.

      • copy

        public BinomialCoef copy()
        Returns a copy of this binomial coefficient matrix allocated by the calling thread (possibly on the stack).
        Specified by:
        copy in interface javolution.lang.ValueType
        Returns:
        an identical and independent copy of this binomial coefficient matrix.

      • recycle

        public static void recycle​(BinomialCoef instance)
        Recycles a BinomialCoef instance immediately (on the stack when executing in a StackContext).

      • toText

        public javolution.text.Text toText()
        Returns the text representation of this binomial coefficient matrix.
        Returns:
        the text representation of this binomial coefficient matrix.