Package de.tilman_neumann.jml.roots

Class SqrtReal

java.lang.Object

de.tilman_neumann.jml.roots.SqrtReal

public class SqrtReal
extends Object

Compute square root of large numbers using Heron's method with a good initial guess. Adapted from http://www.merriampark.com/bigsqrt.htm

Author:

Tilman Neumann

Constructor Summary

Constructors

Constructor	Description
SqrtReal()

Method Summary

Modifier and Type	Method	Description
static void	main(String[] argv)	Test.
static BigDecimal	sqrt(BigDecimal x, Scale resultScale)	Compute square root.
static BigDecimal	sqrt(BigDecimal x, BigDecimal guess, Scale resultScale)	Compute square root with initial guess.

Methods inherited from class java.lang.Object

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

Constructor Detail

SqrtReal

public SqrtReal()

Method Detail

sqrt

public static BigDecimal sqrt(BigDecimal x,
                              Scale resultScale)

Compute square root.

Parameters:

x - argument

resultScale - desired precision in after-comma digits

Returns:

sqrt(x) with error < 0.5*10^-resultScale, i.e. resultScale decimal digits are rounded correctly

sqrt

public static BigDecimal sqrt(BigDecimal x,
                              BigDecimal guess,
                              Scale resultScale)

Compute square root with initial guess.

Parameters:

x - argument

guess - initial guess of sqrt(x)

resultScale - desired precision in after-comma digits

Returns:

sqrt(x) with error < 0.5*10^-resultScale, i.e. resultScale decimal digits are rounded correctly

main

public static void main(String[] argv)

Test.

Parameters:

argv - command line arguments