kcl.waterloo.math

Class Precise

java.lang.Object

kcl.waterloo.math.Precise

public class Precise
extends java.lang.Object

Method Summary

Modifier and Type	Method and Description
static java.math.BigDecimal[]	cumprod(double[] in) Returns the cumulative sum for a double[] as a BigDecimal
static java.math.BigDecimal[]	cumsum(double[] in) Returns the cumulative sum for a double[] as a BigDecimal
static java.math.BigDecimal	dot(double[] in1, double[] in2)
static java.math.BigDecimal	factorial(java.math.BigDecimal n) Returns the factorial as a BigDecimal.
static java.math.BigDecimal	factorial(long n) Returns the factorial as a BigDecimal.
static java.util.LinkedHashMap	getFactorialTable()
static java.math.BigDecimal	mean(double[] in) Returns the sumsq for a double[].
static java.math.BigDecimal	nCk(java.math.BigDecimal n, java.math.BigDecimal k) Accurately returns the binomial (N choose K) as a BigDecimal
static java.math.BigDecimal	nCk(int n, int k) Accurately returns the binomial (N choose K) as a BigDecimal
static java.math.BigDecimal	nCk(long n, long k) Accurately returns the binomial (N choose K) as a BigDecimal
static void	reset() Resets the internal hashmaps - thus freeing memory
static java.math.BigDecimal	sum(double[] in) Returns the sum for a double[].
static java.math.BigDecimal	sumsq(double[] in) Returns the sum of squares for a double[] accumulated as a BigDecimal

Methods inherited from class java.lang.Object

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

Method Detail

sum

public static java.math.BigDecimal sum(double[] in)

Returns the sum for a double[]. The sum is accumulated as a BigDecimal

Parameters:

in -

Returns:

a BigDecimal

cumsum

public static java.math.BigDecimal[] cumsum(double[] in)

Returns the cumulative sum for a double[] as a BigDecimal

Parameters:

in -

Returns:

BigDecimal

cumprod

public static java.math.BigDecimal[] cumprod(double[] in)

Returns the cumulative sum for a double[] as a BigDecimal

Parameters:

in -

Returns:

a BigDecimal

sumsq

public static java.math.BigDecimal sumsq(double[] in)

Returns the sum of squares for a double[] accumulated as a BigDecimal

Parameters:

in - BigDecimal

Returns:

`

dot

public static java.math.BigDecimal dot(double[] in1,
                                       double[] in2)

mean

public static java.math.BigDecimal mean(double[] in)

Returns the sumsq for a double[]. The mean is calculated as a BigDecimal but returned as double

Parameters:

in -

Returns:

a BigDecimal

reset

public static void reset()

Resets the internal hashmaps - thus freeing memory

getFactorialTable

public static java.util.LinkedHashMap getFactorialTable()

factorial

public static java.math.BigDecimal factorial(long n)

Returns the factorial as a BigDecimal. For n less than 0 returns null. For n=0,1 returns 1. Otherwise returns n!. Once calculated, values of n and n! are stored in a HashMap. Subsequent calls with input n will return the stored value of n!.

Parameters:

n - - type long

Returns:

n! - type BigDecimal

factorial

public static java.math.BigDecimal factorial(java.math.BigDecimal n)

Returns the factorial as a BigDecimal. For n less than 0 returns null. For n=0,1 returns 1. Otherwise returns n! Once calculated, values of n and n! are stored in a HashMap. Subsequent calls with input n will return the stored value of n!.

Parameters:

n - - type BigDecimal

Returns:

n! - type BigDecimal

nCk

public static java.math.BigDecimal nCk(int n,
                                       int k)

Accurately returns the binomial (N choose K) as a BigDecimal

For k< 0, return ZERO

For k==0 or k ==n return ONE

For k==1 return n

Otherwise returns

n!/((n*k)! k!)

Parameters:

n - - int

k - - int

Returns:

n!/((n*k)! k!)

as a BigDecimal

nCk

public static java.math.BigDecimal nCk(long n,
                                       long k)

Accurately returns the binomial (N choose K) as a BigDecimal

For k< 0, return ZERO

For k==0 or k ==n return ONE

For k==1 return n

Otherwise returns

n!/((n*k)! k!)

Parameters:

n - - long

k - - long

Returns:

n!/((n*k)! k!)

as a BigDecimal

nCk

public static java.math.BigDecimal nCk(java.math.BigDecimal n,
                                       java.math.BigDecimal k)

Accurately returns the binomial (N choose K) as a BigDecimal

For k< 0, return ZERO

For k==0 or k ==n return ONE

For k==1 return n

Otherwise returns

n!/((n*k)! k!)

Parameters:

n - - BigDecimal

k - - BigDecimal

Returns:

n!/((n*k)! k!)

as a BigDecimal