Package org.apache.commons.numbers.arrays

Class LinearCombination

java.lang.Object

org.apache.commons.numbers.arrays.LinearCombination

public class LinearCombination
extends java.lang.Object

Computes linear combinations accurately. This method computes the sum of the products ai bi to high accuracy. It does so by using specific multiplication and addition algorithms to preserve accuracy and reduce cancellation effects. It is based on the 2005 paper Accurate Sum and Dot Product by Takeshi Ogita, Siegfried M. Rump, and Shin'ichi Oishi published in SIAM J. Sci. Comput.

Constructor Summary

Constructors

Constructor	Description
LinearCombination()

Method Summary

Modifier and Type	Method	Description
static double	value(double[] a, double[] b)
static double	value(double a1, double b1, double a2, double b2)
static double	value(double a1, double b1, double a2, double b2, double a3, double b3)
static double	value(double a1, double b1, double a2, double b2, double a3, double b3, double a4, double b4)

Methods inherited from class java.lang.Object

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

Constructor Details

LinearCombination

public LinearCombination()

Method Details

value

public static double value(double[] a, double[] b)

Parameters:

a - Factors.

b - Factors.

Returns:

\( \sum_i a_i b_i \).

Throws:

java.lang.IllegalArgumentException - if the sizes of the arrays are different.

value

public static double value(double a1, double b1, double a2, double b2)

Parameters:

a1 - First factor of the first term.

b1 - Second factor of the first term.

a2 - First factor of the second term.

b2 - Second factor of the second term.

Returns:

\( a_1 b_1 + a_2 b_2 \)

See Also:

value(double, double, double, double, double, double), value(double, double, double, double, double, double, double, double), value(double[], double[])

value

public static double value(double a1, double b1, double a2, double b2, double a3, double b3)

Parameters:

a1 - First factor of the first term.

b1 - Second factor of the first term.

a2 - First factor of the second term.

b2 - Second factor of the second term.

a3 - First factor of the third term.

b3 - Second factor of the third term.

Returns:

\( a_1 b_1 + a_2 b_2 + a_3 b_3 \)

See Also:

value(double, double, double, double), value(double, double, double, double, double, double, double, double), value(double[], double[])

value

public static double value(double a1, double b1, double a2, double b2, double a3, double b3, double a4, double b4)

Parameters:

a1 - First factor of the first term.

b1 - Second factor of the first term.

a2 - First factor of the second term.

b2 - Second factor of the second term.

a3 - First factor of the third term.

b3 - Second factor of the third term.

a4 - First factor of the fourth term.

b4 - Second factor of the fourth term.

Returns:

\( a_1 b_1 + a_2 b_2 + a_3 b_3 + a_4 b_4 \)

See Also:

value(double, double, double, double), value(double, double, double, double, double, double), value(double[], double[])