//+------------------------------------------------------------------+ //| ThreePoleButterworthFilter.mq4 | //| | //| Three-Pole Butterworth Filter | //| | //| Algorithm taken from book | //| "Cybernetics Analysis for Stock and Futures" | //| by John F. Ehlers | //| | //| contact@mqlsoft.com | //| http://www.mqlsoft.com/ | //+------------------------------------------------------------------+ #property copyright "Coded by Witold Wozniak" #property link "www.mqlsoft.com" #property indicator_chart_window #property indicator_buffers 1 #property indicator_color1 Red extern int CutoffPeriod = 15; double Filter[]; int buffers = 0; int drawBegin = 0; double tempReal, rad2Deg, deg2Rad; double coef1, coef2, coef3, coef4; int init() { drawBegin = 4; initBuffer(Filter, "Three-Pole Butterworth Filter", DRAW_LINE); IndicatorBuffers(buffers); IndicatorShortName("Three-Pole Butterworth Filter [" + CutoffPeriod + "]"); tempReal = MathArctan(1.0); rad2Deg = 45.0 / tempReal; deg2Rad = 1.0 / rad2Deg; double a1 = MathExp(-3.14159 / CutoffPeriod); double b1 = 2 * a1 * MathCos(deg2Rad * 1.414 * 180 / CutoffPeriod); double c1 = a1 * a1; coef2 = b1 + c1; coef3 = -(c1 + b1 * c1); coef4 = c1 * c1; coef1 = (1.0 - b1 + c1) * (1.0 - c1) / 8.0; return (0); } int start() { if (Bars <= drawBegin) return (0); int countedBars = IndicatorCounted(); if (countedBars < 0) return (-1); if (countedBars > 0) countedBars--; int s, limit = Bars - countedBars - 1; for (s = limit; s >= 0; s--) { Filter[s] = coef1 * (P(s) + 3.0 * P(s + 1) + 3.0 * P(s + 2) + P(s + 3)) + coef2 * Filter[s + 1] + coef3 * Filter[s + 2] + coef4 * Filter[s + 3]; if (s > Bars - 4) { Filter[s] = P(s); } } return (0); } double P(int index) { return ((High[index] + Low[index]) / 2.0); } void initBuffer(double array[], string label = "", int type = DRAW_NONE, int arrow = 0, int style = EMPTY, int width = EMPTY, color clr = CLR_NONE) { SetIndexBuffer(buffers, array); SetIndexLabel(buffers, label); SetIndexEmptyValue(buffers, EMPTY_VALUE); SetIndexDrawBegin(buffers, drawBegin); SetIndexShift(buffers, 0); SetIndexStyle(buffers, type, style, width); SetIndexArrow(buffers, arrow); buffers++; }
Sample
Analysis
Market Information Used:
Series array that contains the highest prices of each bar
Series array that contains the lowest prices of each bar
Indicator Curves created:
Implements a curve of type type
Indicators Used:
Custom Indicators Used:
Order Management characteristics:
Other Features: