Contents
- abs
- add
- all_time_high
- all_time_low
- and
- approx
- aroon_down
- aroon_osc
- aroon_up
- atr
- bb_lower
- bb_upper
- bb_width
- cci
- change
- cond
- count
- cross
- crossover
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- cumsum
- days_since
- dev
- deviation
- div
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- eq
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- highest
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- kc_lower
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- kc_upper
- kcw
- loss
- lowest
- lowest_bars_ago
- lt
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- max
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- mul
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- pow
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- rising
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- sqrt
- stdev
- stoch_d
- stoch_k
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- sub
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- swma
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- universe_percentile
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- vwma
- weeks_since
- wilderma
- williams_r
- wma
- years_since
No matches
bb_width
Bollinger Bands Width (upper_band - lower_band)
bb_width(source, period, num_stdev)
Parameters
| Name | Type | Description |
|---|---|---|
source |
field | Data series |
period |
int | Stdev period |
num_stdev |
float | Number of standard deviations |
Formula
BB Width = 2 * num_stdev * stdev(source, period)Examples
/* narrower bands (lower volatility) than 20 bars ago */
bb_width(close, 20, 2) < bb_width(close, 20, 2)[20];/* wider bands (higher volatility) than 20 bars ago */
bb_width(close, 20, 2) > bb_width(close, 20, 2)[20];/* increasing width (expanding volatility) for 3 consecutive bars */
rising(bb_width(close, 20, 2), 3) == true;/* decreasing width (contracting volatility) for 3 consecutive bars */
falling(bb_width(close, 20, 2), 3) == true;Returns
float
Range
period must be 2-400
Notes
Absolute width -- the two bands' moving averages cancel, so this takes no matype: it has no MA term to select one for