backtrader.indicator module

Backtrader Indicator Module.

This module provides the base Indicator class and related infrastructure for creating and managing technical analysis indicators. It replaces the metaclass-based approach with explicit inheritance and registration.

The Indicator class serves as the foundation for all technical indicators in backtrader, managing line data, minimum periods, and calculation logic.

class backtrader.indicator.IndicatorRegistry

Bases: object

Registry to manage indicator classes and provide caching functionality.

This class replaces the metaclass-based indicator registration and caching mechanism from the original backtrader implementation.

classmethod register(name, indicator_cls)

Register an indicator class in the registry.

Parameters:

• name – Name of the indicator class

• indicator_cls – The indicator class to register

classmethod cleancache()

Clear the indicator cache.

classmethod usecache(onoff)

Enable or disable indicator caching.

Parameters:

onoff – If True, enable caching; if False, disable it

classmethod get_cached_or_create(indicator_cls, *args, **kwargs)

Get cached indicator instance or create new one.

Parameters:

• indicator_cls – The indicator class to instantiate

• *args – Positional arguments for the indicator

• **kwargs – Keyword arguments for the indicator

Returns:

Cached indicator instance if available and caching enabled, otherwise a new indicator instance

class backtrader.indicator.Indicator

Bases: IndicatorBase

Base class for all technical indicators in Backtrader.

This class provides the foundation for creating custom indicators. It manages line data, minimum periods, and calculation logic. Indicators inherit from IndicatorBase and integrate with the LineIterator system for data flow.

_ltype

Line type set to IndType (0) for indicators

csv

Whether to output this indicator to CSV (default: False)

aliased

Whether this indicator has an alias name

csv = False

__getitem__(ago)

CRITICAL FIX: Forward item access to the first line (e.g., sma line)

For indicators with named lines like SMA (which has lines.sma), accessing indicator[0] should return the value from the first line, not the indicator’s own array.

aliased = False

classmethod __init_subclass__(**kwargs)

Handle subclass registration and initialization.

This method is called when a subclass of Indicator is created. It performs: 1. Lines creation using Lines infrastructure 2. Automatic registration in IndicatorRegistry 3. Alias handling for module-level access 4. next/once method setup for calculation modes

Parameters:

**kwargs – Additional keyword arguments

classmethod cleancache()

Clear the indicator cache

classmethod usecache(onoff)

Enable or disable caching

advance(size=1)

Advance indicator lines when data length is less than clock length.

This method supports indicators with data feeds of different lengths (e.g., different timeframes).

Parameters:

size – Number of steps to advance (default: 1)

preonce_via_prenext(start, end)

Implement preonce using prenext for batch calculation.

This is a generic implementation if prenext is overridden but preonce is not. It loops through the range and calls prenext for each step.

Parameters:

• start – Starting index

• end – Ending index

oncestart_via_nextstart(start, end)

Implement oncestart using nextstart for batch calculation.

This is used when nextstart is overridden but oncestart is not.

Parameters:

• start – Starting index

• end – Ending index

once_via_next(start, end)

Implement once using next for batch calculation.

This is used when next is overridden but once is not. It loops through the range and calls next for each step.

Parameters:

• start – Starting index

• end – Ending index

frompackages = ()

packages = ()

class backtrader.indicator.LinePlotterIndicatorBase

Bases: type

Base class for indicators that plot multiple lines.

Note: These classes are not currently used in the project. They are kept for compatibility with the original backtrader.

donew(*args, **kwargs)

Create a new LinePlotterIndicator instance.

Parameters:

• *args – Positional arguments

• **kwargs – Keyword arguments, must include ‘name’

Returns:

(created_object, args, kwargs)

Return type:

tuple

class backtrader.indicator.LinePlotterIndicator

Bases: Indicator, LinePlotterIndicatorBase

Indicator that plots multiple lines.

Note: This class is not currently used in the project.

frompackages = ()

packages = ()