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/*
The Computer Language Shootout
http://shootout.alioth.debian.org/
contributed by Andrei Formiga
modified by Isaac Gouy
*/
object partialsums {
def main(args: Array[String]) = {
accumulate(0,0,0,0,0,0,0,0,0, Integer.parseInt(args(0))+1, 1,1)
}
val twothirds = 2.0 / 3.0
def accumulate(a1: Double, a2: Double, a3: Double, a4: Double, a5: Double,
a6: Double, a7: Double, a8: Double, a9: Double,
n: Double, alt: Double, k: Double) {
if (k < n) {
val k2 = Math.pow(k, 2.0)
val k3 = k2 * k
val sk = Math.sin(k)
val ck = Math.cos(k)
accumulate(
a1 + Math.pow(twothirds, k - 1.0)
,a2 + 1.0 / Math.sqrt(k)
,a3 + 1.0 / (k * (k + 1.0))
,a4 + 1.0 / (k3 * sk*sk)
,a5 + 1.0 / (k3 * ck*ck)
,a6 + 1.0 / k
,a7 + 1.0 / k2
,a8 + alt / k
,a9 + alt / (2.0 * k - 1.0)
,n
,-alt
,k + 1.0
)
} else {
val f = "%.9f\t"
Console.printf( f + "(2/3)^k\n", a1)
Console.printf( f + "k^-0.5\n", a2)
Console.printf( f + "1/k(k+1)\n", a3)
Console.printf( f + "Flint Hills\n", a4)
Console.printf( f + "Cookson Hills\n", a5)
Console.printf( f + "Harmonic\n", a6)
Console.printf( f + "Riemann Zeta\n", a7)
Console.printf( f + "Alternating Harmonic\n", a8)
Console.printf( f + "Gregory\n", a9)
}
}
}
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