pine-script - ジグザグ線の傾き/微分値を計算する

Question

各ジグザグ線の傾き/導関数を計算し、ジグザグ線の上/下に表示したいと思います。これを行う方法？

ジグザグの例:

//@version=4
study("ZigZagSlope", overlay = true, max_bars_back = 500, max_lines_count = 300)
prd = input(defval = 3, title="ZigZag Period", minval = 2, maxval = 50)
showzigzag = input(defval = true, title = "Show Zig Zag")
upcol = input(defval = color.black, title = "Zigzag Up Color")
dncol = input(defval = color.black, title = "Zigzag Down Color")

float ph = highestbars(high, prd) == 0 ? high : na
float pl = lowestbars(low, prd) == 0 ? low : na
var dir = 0
dir := iff(ph and na(pl), 1, iff(pl and na(ph), -1, dir))
var max_array_size = 10
var zigzag = array.new_float(0)

add_to_zigzag(value, bindex)=>
    array.unshift(zigzag, bindex)
    array.unshift(zigzag, value)
    if array.size(zigzag) > max_array_size
        array.pop(zigzag)
        array.pop(zigzag)
    
update_zigzag(value, bindex)=>
    if array.size(zigzag) == 0
        add_to_zigzag(value, bindex)
    else
        if (dir == 1 and value > array.get(zigzag, 0)) or (dir == -1 and value < array.get(zigzag, 0))
            array.set(zigzag, 0, value)
            array.set(zigzag, 1, bindex)
        0.
Round_it(value)=> round(value / syminfo.mintick) * syminfo.mintick

dirchanged = change(dir)
if ph or pl
    if dirchanged
        add_to_zigzag(dir == 1 ? ph : pl, bar_index)
    else
        update_zigzag(dir == 1 ? ph : pl, bar_index)

if showzigzag and array.size(zigzag) >= 4
    var line zzline = na
    float val = array.get(zigzag, 0)
    int point = round(array.get(zigzag, 1))
    if change(val) or change(point)
        float val1 = array.get(zigzag, 2)
        int point1 = round(array.get(zigzag, 3))
        if change(val1) == 0 and change(point1) == 0
            line.delete(zzline)
        zzline := line.new(x1 = point, y1 = val, x2 = point1, y2 = val1, color = dir == 1 ? upcol : dncol, width = 2)

導関数の計算例:

https://www.tradingview.com/script/1Ea3KEUq-MaxWarren-s-Pine-Acceleration-2nd-Derivative/