Groovy example source code file (partialsums.groovy)

This example Groovy source code file (partialsums.groovy) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Groovy tags/keywords

decimalformat, decimalformat, harmonic, harmonic, hills, hills, text, zeta, zeta

The Groovy partialsums.groovy source code

import java.text.DecimalFormat

// ---------------------------------------------------------------------
// The Great Computer Language Shootout
// http://shootout.alioth.debian.org/
//
// Use JRE 1.4 features only [JRE 1.5 'printf' would have helped better
// streamline code]
//
// Contributed by Anthony Borla
// Modified by Alex Tkachman
// ---------------------------------------------------------------------

def calculate()
{
    final double twothirds = 2.0d/3.0d;

    n = Integer.parseInt(args[0])

    double a1 = 0.0d, a2 = 0.0d, a3 = 0.0d, a4 = 0.0d, a5 = 0.0d
    double a6 = 0.0d, a7 = 0.0d, a8 = 0.0d, a9 = 0.0d, alt = -1.0d

    double k = 1.0d
    while (k<=n){
       double k2 = Math.pow(k,2.0d), k3 = k2*k
       double sk = Math.sin(k), ck = Math.cos(k)
       alt = -alt

       a1 = a1 + Math.pow(twothirds,k-1.0d)
       a2 = a2 + Math.pow(k,-0.5d)
       a3 = a3 + 1.0d/(k*(k+1.0d))
       a4 = a4 + 1.0d/(k3 * sk*sk)
       a5 = a5 + 1.0d/(k3 * ck*ck)
       a6 = a6 + 1.0d/k
       a7 = a7 + 1.0d/k2
       a8 = a8 + alt/k
       a9 = a9 + alt/(2.0d*k-1.0d)
       k += 1.0d
    }

    def fmt = new DecimalFormat("##0.000000000")

    result = fmt.format(a1); println "${result}\t(2/3)^k"
    result = fmt.format(a2); println "${result}\tk^-0.5"
    result = fmt.format(a3); println "${result}\t1/k(k+1)"
    result = fmt.format(a4); println "${result}\tFlint Hills"
    result = fmt.format(a5); println "${result}\tCookson Hills"
    result = fmt.format(a6); println "${result}\tHarmonic"
    result = fmt.format(a7); println "${result}\tRiemann Zeta"
    result = fmt.format(a8); println "${result}\tAlternating Harmonic"
    result = fmt.format(a9); println "${result}\tGregory"
}

// --------------------------------

long start = System.currentTimeMillis ()
calculate()
println "${System.currentTimeMillis () - start}ms"