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QuanTAlib/lib/trends_IIR/decycler/decycler.pine
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Miha Kralj 3dd05f23e4 Refactor indicators to include "Ehlers" in names and descriptions for clarity
- Updated the name and description of the Hilbert Trendline (HTIT) to "Ehlers Hilbert Transform Instantaneous Trend (HTIT)".
- Changed the name and description of the MESA Adaptive Moving Average (MAMA) to "Ehlers MESA Adaptive Moving Average".
- Modified the Center of Gravity (CG) indicator to "Ehlers Center of Gravity (CG)".
- Renamed the Detrended Synthetic Price (DSP) to "Ehlers Detrended Synthetic Price (DSP)".
- Updated the Autocorrelation Periodogram (EACP) to "Ehlers Autocorrelation Periodogram (EACP)".
- Changed the Homodyne Discriminator (HOMOD) to "Ehlers Homodyne Discriminator (HOMOD)".
- Updated the Hilbert Transform Dominant Cycle Period and Phase indicators to include "Ehlers" in their names.
- Renamed the Hilbert Transform Phasor Components to "Ehlers Hilbert Transform Phasor Components (HT_PHASOR)".
- Updated the SineWave indicator to "Ehlers Hilbert Transform SineWave (HT_SINE)".
- Changed the Phasor Analysis indicator to "Ehlers Hilbert Transform Phasor Components (HT_PHASOR)".
- Updated the SSF-Based Detrended Synthetic Price to "Ehlers SSF Detrended Synthetic Price (SSFDSP)".
- Renamed the Ultimate Channel to "Ehlers Ultimate Channel (UCHANNEL)".
- Added new indicators: Moving Average Variable Period (MAVP), Ehlers Predictive Moving Average (PMA), Ehlers Reverse EMA (REVERSEEMA), and Ehlers Trendflex Indicator (TRENDFLEX).
- Updated various SVG badges to reflect changes in classes, comments, source files, lines of code, methods, and public types.
2026-02-18 19:08:15 -08:00

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// The MIT License (MIT)
// © mihakralj
//@version=6
// Indicator algorithm (C) 2004-2024 John F. Ehlers
indicator("Ehlers Decycler (DECYCLER)", "DECYCLER", overlay=true)
//@function Calculates Ehlers Decycler by subtracting a 2-pole Butterworth high-pass filter from price
//@param source Series to calculate Decycler from
//@param period Cutoff period for the high-pass filter (>= 1)
//@returns Decycler value (source minus high-pass filtered component)
//@optimized Uses 2-pole Butterworth HP with O(1) complexity per bar
decycler(series float source, simple int period) =>
if period <= 0
runtime.error("Period must be positive")
float src = na(source) ? 0.0 : source
// Butterworth 2-pole HP coefficient: alpha = (cos(x) + sin(x) - 1) / cos(x)
// where x = 0.707 * 2pi / period
float arg = 0.707 * 2.0 * math.pi / period
float alpha = (math.cos(arg) + math.sin(arg) - 1.0) / math.cos(arg)
float omah = 1.0 - alpha * 0.5
float oma = 1.0 - alpha
float a1 = omah * omah
float b1 = 2.0 * oma
float c1 = -(oma * oma)
// 2-pole HP: HP[n] = a1*(x - 2*x[1] + x[2]) + b1*HP[1] + c1*HP[2]
float diff_src = nz(src) - 2.0 * nz(src[1]) + nz(src[2])
var float hp = 0.0
var float hp1 = 0.0
float new_hp = bar_index < 2 ? 0.0 : a1 * diff_src + b1 * hp + c1 * hp1
hp1 := hp
hp := new_hp
// Decycler = price - high-pass
na(source) ? na : src - new_hp
// ---------- Main loop ----------
// Inputs
i_period = input.int(60, "Period", minval=1, tooltip="Cutoff period for the high-pass filter")
i_source = input.source(close, "Source")
// Calculation
decycler_value = decycler(i_source, i_period)
// Plot
plot(decycler_value, "DECYCLER", color=color.yellow, linewidth=2)