Golang Fibonacci Test

package main

import (
	"fmt"
	"time"
)

func main() {
	n := 999999
	// fmt.Println(fibonacci_recursion(n))
	// fmt.Println(fibonacci_recursion_append(n))
	// fmt.Println(fibonacci_single_channel(n))
	// fmt.Println(fibonacci_multiple_channel(n))
	t := time.Now()
	// fibonacci_recursion(n)
	// fmt.Printf("%v:Recursion Caculate\n", time.Now().Sub(t))
	// t = time.Now()
	fibonacci_recursion_append(n)
	fmt.Printf("%v:Recursion Append\n", time.Now().Sub(t))
	t = time.Now()
	fibonacci_single_channel(n)
	fmt.Printf("%v:Single Channel\n", time.Now().Sub(t))
	t = time.Now()
	fibonacci_multiple_channel(n)
	fmt.Printf("%v:Multiple Channel\n", time.Now().Sub(t))
}

func fibonacci_recursion(n int) []int64 {
	arr := make([]int64, n)
	// fmt.Println(unsafe.Pointer(&arr))
	fibonacci_recursion_calc(&arr, n)
	return arr
}

func fibonacci_recursion_calc(arr *[]int64, n int) int64 {
	var v int64
	if n == 1 {
		v = 1
	} else if n == 2 {
		v = 1
	} else {
		v = fibonacci_recursion_calc(arr, n-2) + fibonacci_recursion_calc(arr, n-1)
	}
	// (*arr)[n-1] = v
	return v
}

func fibonacci_recursion_append(n int) []int64 {
	if n == 1 {
		return []int64{1}
	}
	if n == 2 {
		return []int64{1, 1}
	}
	arr := fibonacci_recursion_append(n - 1)
	return append(arr, arr[n-2]+arr[n-3])
}

func fibonacci_single_channel(n int) []int64 {
	arr := make([]int64, n)
	exit := make(chan bool)
	cache := make(chan int, 220000)
	go func() {
		for i := 0; i < n; i++ {
			cache <- i
		}
		exit <- true
	}()
	go func() {
		for {
			v := <-cache
			if v == 0 {
				arr[0] = 1
			} else if v == 1 {
				arr[1] = 1
			} else {
				arr[v] = arr[v-1] + arr[v-2]
			}
		}
	}()
	<-exit
	return arr
}

func fibonacci_multiple_channel(n int) []int64 {
	arr := make([]int64, n)
	input := make(chan int64, 200)
	a, b, output := make(chan int64, 200), make(chan int64, 200), make(chan int64, 200)
	go func() {
		input <- 1
		input <- 1
		<-a
		for {
			input <- <-a + <-b
		}
	}()
	go func() {
		for {
			v := <-input
			a <- v
			b <- v
			output <- v
		}
	}()
	for i := 0; i < n; i++ {
		arr[i] = <-output
	}
	return arr
}