mirror of
https://github.com/mihakralj/QuanTAlib.git
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Miha Kralj
56 lines
1.3 KiB
Plaintext
56 lines
1.3 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("Elder Ray Index (ERI)", "ERI", overlay=false)
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//@function Calculates Elder Ray Index (Bull Power and Bear Power)
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//@param period EMA period for the centerline
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//@returns tuple [bullPower, bearPower] measuring buying/selling pressure
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eri(simple int period) =>
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if period <= 0
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runtime.error("Period must be greater than 0")
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float alpha = 2.0 / (period + 1.0)
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float beta = 1.0 - alpha
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var float ema = 0.0
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var float e = 1.0
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var bool warmup = true
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var bool first = true
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float src = nz(close)
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if first
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ema := src
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first := false
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else
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ema := alpha * src + beta * ema
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float emaVal = src
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if warmup
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e *= beta
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float c = e > 1e-10 ? 1.0 / (1.0 - e) : 1.0
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emaVal := ema * c
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if e <= 1e-10
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warmup := false
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else
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emaVal := ema
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float bullPower = high - emaVal
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float bearPower = low - emaVal
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[bullPower, bearPower]
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// ---------- Main loop ----------
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// Inputs
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i_period = input.int(13, "Period", minval=1, maxval=500)
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// Calculation
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[bull, bear] = eri(i_period)
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// Plot
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plot(bull, "Bull Power", color.new(color.green, 0), 2)
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plot(bear, "Bear Power", color.new(color.red, 0), 2)
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hline(0, "Zero", color=color.gray, linestyle=hline.style_dotted)
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