WHALE ENGINE
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WHALE ENGINE

Bollinger Band Width (bbw)

[[bbw]] measures the distance between the Bollinger Bands around their middle average. You can use it to identify volatility contraction or expansion phases, filter market conditions, or compare multiple parameter setups in grid search.

BBW does not tell you price direction. A high value means the bands are wider and recent volatility is stronger. A lower value means the bands are tighter and the market is quieter.

Block declaration

A strategy can contain multiple [[bbw]] blocks. Each block produces one numeric series representing the BBW value.

Examples

Minimal setup

This block computes BBW from close using the default settings: a 20-period window and a multiplier of 2.0.

[[bbw]]
id = "bbw"

Custom fixed setup

This block uses custom length and multiplier values.

[[bbw]]
id         = "bbw"
length     = 24
multiplier = 2.4

Search for the optimal period and multiplier

This block explores ranges of values for length and multiplier to identify the best-performing configuration.

[[bbw]]
id               = "bbw"
length.start     = 10
length.stop      = 30
multiplier.start = 1.0
multiplier.stop  = 3.0
multiplier.step  = 0.2

Dedicated timeframe

This BBW block uses a dedicated daily timeframe. The price series needed to compute the bands are taken from this timeframe (timeframe = "D"), rather than from the primary timeframe defined in [backtest]. See the Exchanges, Symbols and Timeframes page for alignment rules between this timeframe and the primary timeframe.

[[bbw]]
id        = "bbw"
timeframe = "D"

Specific symbol

This block reads its candles from the specific symbol BINANCE:ETHUSDT. See the Exchanges, Symbols and Timeframes page for alignment with the main symbol.

[[bbw]]
id     = "bbw"
symbol = "BINANCE:ETHUSDT"

Parameters

ParameterDescription
id
String
Required		Unique series name.
source
 String
 or Array
 Optional		Input series used for the calculation.
Accepted forms: source = "hl2" or source = ["close", "hl2"].
Each value can be either a standard price source (open, close, high, low, hl2, hlc3, ohlc4, hlcc4, volume) or the id of another indicator.
Default value: "close"
length
Integer or Range
Optional		SMA and standard deviation window; must be ≥ 1. Default value: 20.

Usage:
• Fixed: length = value
• Grid search:
 – length.start = min_value
 – length.stop = max_value
 – length.step = value (optional, default 1)
multiplier
Decimal or Range
Optional		Standard deviation factor. Default value: 2.0.

Usage:
• Fixed: multiplier = value
• Grid search:
 – multiplier.start = min_value
 – multiplier.stop = max_value
 – multiplier.step = value (optional, default 1)
symbol
String or Array
Optional		Market symbol(s) used when source contains standard prices (open, close, high, low, hl2, hlc3, ohlc4, hlcc4, volume).
If source mixes standard prices and indicator ids, symbol is applied only to combinations based on standard prices.
If source contains only indicator ids, symbol is ignored.
For symbol format and alignment rules, see Exchanges, Symbols and Timeframes.
timeframe
String or Array
Optional		Timeframe on which this indicator is computed.
If timeframe is omitted, the computation uses the grid’s main timeframe defined in [backtest].
For accepted formats and timeframe alignment rules, see Exchanges, Symbols and Timeframes.

Available variables

The BBW block exposes one numeric series and its parameters, along with the input source, symbol, and timeframe.

Assume the block is configured as:

[[bbw]]
id = "bbw"

Then:

VariableDescription
bbw or bbw[0]
Decimal		Current BBW value.
bbw[n]
Decimal		BBW value from n candles ago.
bbw.length
Decimal		Length in use.
bbw.multiplier
Decimal		Multiplier in use.
bbw.source
String		Input series name.
bbw.symbol
String		Symbol used.
bbw.timeframe
String		Timeframe used.
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