A Tour of Go 47: Advanced Exercise: Complex cube roots

gistfile1.go

package main

import (
	"fmt"
	"math/cmplx"
)

func Cbrt(x complex128) complex128 {
	z := complex(1.0, 0)
	for cmplx.Abs(z*z*z-x) > 1e-9 {
		z = z - (z*z*z-x)/(3*z*z)
	}
	return z
}

func main() {
	test := complex(2, 1)
	fmt.Println(Cbrt(test))
	fmt.Println(cmplx.Pow(test, 1.0/3))
}