MQL to Pine Script conversion yields different results

External question — Stack Overflow Stack Exchange Author: andymo Original post: https://stackoverflow.com/questions/70129601 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. I am trying to convert an MQL4 indicator into Pine Script but it yields a totally different output; the indicator values do not match. The MQL4 indicator line is smoother compared to PineScript The MQL4 indicator code is #property indicator_separate_window #property indicator_buffers 1 #property indicator_color1 Crimson #property indicator_width1 2 extern int period = 20; double Signal_Buffer[]; int init() { IndicatorDigits( Digits + 4 ); IndicatorShortName("Indi (" + string(period) + ")"); SetIndexBuffer(0, Signal_Buffer); SetIndexStyle(0, DRAW_LINE); SetIndexLabel(0, "Indi (" + string(period) + ")"); return (0); } int start() { int bars_loaded = IndicatorCounted(); if (bars_loaded > 0) bars_loaded--; int total_bars = Bars - bars_loaded; double current_high = 0; double current_low = 0; double high_low_median = 0; double signal = 0; double a = 0; double b = 0; for (int i = 0; i < total_bars; i++) { current_high = High[iHighest(Symbol(), Period(), MODE_HIGH, period, i)]; current_low = Low[iLowest(Symbol(), Period(), MODE_LOW, period, i)]; high_low_median = (High[i] + Low[i]) / 2.0; a = 0.66 * ( (high_low_median - current_low) / (current_high - current_low) - 0.5 ) + 0.67 * b; a = MathMin( MathMax( a, -0.999 ), 0.999 ); Signal_Buffer[i] = MathLog( ( a + 1.0 ) / ( 1 - a ) ) / 2.0 + signal / 2.0; b = a; signal = Signal_Buffer[i]; } return (0); } and the Pine Script code is //@version=5 indicator(title='Indi', shorttitle='Indi') per = input.int( defval=20, title='Period', minval=1 ) a = 0.0 b = 0.0 signal = 0.0 h = ta.highest( high, per ) l = ta.lowest( low, per ) m = hl2 a := 0.66 * ( (m - l) / (h - l) - 0.5 ) + 0.67 * b a := math.min( math.max( a, -0.999 ), 0.999 ) signal := math.log( ( a + 1.0 ) / ( 1 - a ) ) / 2.0 + signal / 2.0 b := a plot( signal )

External answer — Stack Overflow Stack Exchange Author: rumpypumpydumpy Original post: https://stackoverflow.com/a/70131294 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. I think maybe you need to replace b with nz(a[1] in this line : a = 0.66 * ( (high_low_median - current_low) / (current_high - current_low) - 0.5 ) + 0.67 * b; to a = 0.66 * ( (high_low_median - current_low) / (current_high - current_low) - 0.5 ) + 0.67 * nz(a[1]);