Golang tour #47

go_tour_47.go

package main

import ("fmt"
        "math/cmplx"
        )

func Cbrt(x complex128) complex128 {
    guess := x/2
    // assumes stability after 20 iterations
    for i:=0;i<20;i++ {
        	guess = guess-(cmplx.Pow(guess, 3) -x)/(3*cmplx.Pow(guess,2))
    }
    return guess
}

func main() {
    fmt.Println("My func: ", Cbrt(2))
    fmt.Println("Builtin: ", cmplx.Pow(2, 1.0/3.0))
}