jahuwaldt.js.math

Class BinomialCoef

java.lang.Object

jahuwaldt.js.math.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

Modifier and Type	Method and 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.