mirror of
https://github.com/mihakralj/QuanTAlib.git
synced 2026-07-29 18:17:43 +00:00
Miha Kralj
65 lines
2.3 KiB
Plaintext
65 lines
2.3 KiB
Plaintext
// Licensed under the Apache License, Version 2.0
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// © mihakralj
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//@version=6
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indicator("Choppiness Index", "CHOP", overlay=false)
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//@function Calculates Choppiness Index to measure market trendiness
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//@param length Lookback period for calculation
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//@returns CHOP value between 0 and 100 (lower=trending, higher=choppy)
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//@references E.W. Dreiss, Australian commodity trader
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//@optimized O(n) with circular buffers for TR sum and high/low tracking
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chop(simple int length) =>
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if length <= 1
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runtime.error("Length must be > 1")
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var float sum_tr = 0.0
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var int head = 0
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var int filled = 0
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var array<float> atr_buf = array.new_float(length, na)
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var array<float> high_buf = array.new_float(length, na)
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var array<float> low_buf = array.new_float(length, na)
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float prevClose = nz(close[1], close)
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float tr = math.max(high - low, math.max(math.abs(high - prevClose), math.abs(low - prevClose)))
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float out = array.get(atr_buf, head)
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if not na(out)
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sum_tr -= out
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else
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filled += 1
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array.set(atr_buf, head, tr)
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array.set(high_buf, head, high)
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array.set(low_buf, head, low)
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sum_tr += tr
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int win = math.min(filled, length)
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float hhv = -1e100
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float llv = 1e100
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for k = 0 to win - 1
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int idx = (head - k + length) % length
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float h = array.get(high_buf, idx)
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float l = array.get(low_buf, idx)
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if not na(h)
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hhv := math.max(hhv, h)
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if not na(l)
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llv := math.min(llv, l)
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head := (head + 1) % length
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float price_range = hhv - llv
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float chop_value = na
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if win >= 2 and price_range > 0
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float log_ratio = math.log(sum_tr / price_range) / math.log(10)
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float log_len = math.log(win) / math.log(10)
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chop_value := 100.0 * log_ratio / log_len
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chop_value := math.max(0.0, math.min(100.0, chop_value))
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chop_value
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// ---------- Main loop ----------
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// Inputs
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i_length = input.int(14, "Length", minval=2)
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// Calculation
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chop_value = chop(i_length)
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// Plot
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plot(chop_value, "CHOP", color=color.yellow, linewidth=2)
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hline(61.8, "High Threshold", color=color.new(color.red, 50), linestyle=hline.style_dashed)
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hline(38.2, "Low Threshold", color=color.new(color.green, 50), linestyle=hline.style_dashed)
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hline(50, "Midline", color=color.new(color.gray, 70), linestyle=hline.style_dotted)
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