PSAR X

--Haas interpretation author: HashSwingBagHolder
--Inspired by: 'PSAR X' on TV by RafaelZioni  

start = 0.2
increment = 0.2
maximum = 0.8

len = 14
off= 0
dev= 1.9

OptimizedForInterval(0,
    function()

function PSAR(start, increment, maximum, src, len, off, dev)
    function pine_linreg(src, len , offset)
        intercept = LINEARREG(src, len, LR_Intercept)
        slope = LINEARREG(src, len, LR_Slope)
        return intercept + slope * (len - 1 - offset)
    end

    bar_index = Load('bar_index', 0)
    Save('bar_index', bar_index + 1)

    close = ClosePrices()
    high = HighPrices()
    low = LowPrices()
    
    c = close 

    psar = SAR(high, low, increment, maximum)
    cp = psar
    
    lreg = pine_linreg(cp, len, off) 
    lreg_x  = pine_linreg(cp, len, off+1)
    b = bar_index
    s = lreg - lreg_x
    intr = lreg - b*s
    dS = 0.0

    for i=1 , len do
        dS = dS + Pow(cp[i]-(s*(b-i)+intr), 2)  
    end

    de = Sqrt(dS/(len))
    up = (-de*dev) + psar
    down= (de*dev) + psar

    
    prev_up_t = Load('prev_up_t', c)

    prev_down_t = Load('prev_down_t', c)

    up_t   = c[2] > prev_up_t   and Max(up, prev_up_t)   or up

    down_t = c[2] < prev_down_t and Min(down, prev_down_t) or down

    Save('prev_up_t', up_t)
    Save('prev_down_t', down_t)

    prev_trend= Load('prev_trend', nil)

    trend = c > prev_down_t  and  1 or c < prev_up_t and -1 or (prev_trend != nil and prev_trend or 1)


    Save('prev_trend', trend)

    r_line = trend ==1 and up_t or down_t

    return r_line
end

r_line = PSAR(start, increment, maximum, c, len, off, dev)

Plot(0,"r_line1",r_line)

end
)