bookExamples.ch05ControlStructs
Class Pi

java.lang.Object
  bookExamples.ch05ControlStructs.Pi

public class Pi
extends java.lang.Object

Constructor Summary

Pi()

Method Summary

static java.math.BigDecimal	arctan(int inverseX, int scale) Compute the value, in radians, of the arctangent of the inverse of the supplied integer to the specified number of digits after the decimal point.
static void	arctanThread1(int inverseX, int scale)
static void	arctanThread2(int inverseX, int scale)
static java.math.BigDecimal	computePi(int digits) Compute the value of pi to the specified number of digits after the decimal point.
static void	main(java.lang.String[] args)

Methods inherited from class java.lang.Object

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

Constructor Detail

Pi

public Pi()

Method Detail

main

public static void main(java.lang.String[] args)
                 throws java.lang.NumberFormatException

Throws:

java.lang.NumberFormatException

computePi

public static java.math.BigDecimal computePi(int digits)

Compute the value of pi to the specified number of digits after the decimal point. The value is computed using Machin's formula:

pi/4 = 4*arctan(1/5) - arctan(1/239)

and a power series expansion of arctan(x) to sufficient precision.

arctanThread1

public static void arctanThread1(int inverseX,
                                 int scale)

arctanThread2

public static void arctanThread2(int inverseX,
                                 int scale)

arctan

public static java.math.BigDecimal arctan(int inverseX,
                                          int scale)

Compute the value, in radians, of the arctangent of the inverse of the supplied integer to the specified number of digits after the decimal point. The value is computed using the power series expansion for the arc tangent:

arctan(x) = x - (x^3)/3 + (x^5)/5 - (x^7)/7 + (x^9)/9 ...