SCUM

class SCUM(season_length=1, forecasters=None, clip_negative=True, dotm_max_length=5000)[source]

Bases: BaseForecaster, IterativeForecastingMixin

Simple Combination of Univariate Models forecaster.

SCUM is the M4 submission by Petropoulos and Svetunkov [1]. It combines point forecasts from four univariate models by taking the median at each horizon: automatic exponential smoothing (ETS), complex exponential smoothing (CES), automatic ARIMA, and dynamic optimized theta (DOTM).

The forecast combination is delegated to aeon.forecasting.ensembles.EnsembleForecaster, with SCUM defining the default component pool and applying the non-negative clipping used in the M4 implementation.

Parameters:
season_lengthint, default=1

Seasonal period/frequency passed to seasonal-capable component models.

forecasterssequence or None, default=None

Optional custom forecaster pool. Each entry can be either a forecaster instance or a (name, forecaster) tuple. If None, the SCUM pool (AutoETS, AutoCES, AutoARIMA, DOTM) is used.

clip_negativebool, default=True

If True, replace negative combined forecasts with zero, following the M4 implementation for non-negative data.

dotm_max_lengthint or None, default=5000

Maximum number of most recent observations passed to DOTM. The paper applies DOTM only to the last 5000 observations for very long series. Set to None to disable this window.

Attributes:
ensemble_EnsembleForecaster

Fitted median ensemble used to combine the component forecasts.

forecasters_list of tuple

Fitted (name, forecaster) pool used by SCUM.

forecast_float

Stored one-step-ahead combined forecast.

Notes

Capabilities

Missing Values

No

Multithreading

No

Univariate

Yes

Multivariate

No

Horizon

No

Exogenous

No

This implementation diverges from the original M4 submission [1] in a few places, mainly because it reuses aeon’s existing component forecasters:

  • ARIMA is non-seasonal. The paper uses the seasonal auto.arima from the R forecast package (non-seasonal orders up to 5, seasonal AR/MA up to 2). aeon’s AutoARIMA has no seasonal capability and a narrower order search, so the ARIMA member ignores seasonality and season_length is not passed to it.

  • No ETS frequency switch. The paper selects the ETS model with forecast::ets for frequencies <= 24 and smooth::es (which supports frequencies > 24 and a larger model pool) otherwise. Here a single AutoETS is used for all frequencies; this is adequate because aeon’s AutoETS already handles seasonal periods > 24, but it does not reproduce the larger es model pool used for weekly/hourly data.

  • Point forecasts only. The paper also produces median-combined prediction intervals; this implementation combines point forecasts only.

The four-model pool, the per-horizon median combination, the post-median non-negative clipping, and the DOTM-only most-recent-5000-observations window all follow the paper.

References

[1] (1,2)

Petropoulos, F. and Svetunkov, I. (2020). A simple combination of univariate models. International Journal of Forecasting, 36(1), 110-115.

Methods

clone([random_state])

Obtain a clone of the object with the same hyperparameters.

fit(y[, exog, axis])

Fit forecaster to series y.

forecast(y[, exog, axis])

Forecast the next horizon steps ahead of y.

get_class_tag(tag_name[, raise_error, ...])

Get tag value from estimator class (only class tags).

get_class_tags()

Get class tags from estimator class and all its parent classes.

get_fitted_params([deep])

Get fitted parameters.

get_params([deep])

Get parameters for this estimator.

get_tag(tag_name[, raise_error, ...])

Get tag value from estimator class.

get_tags()

Get tags from estimator.

iterative_forecast(y, prediction_horizon[, ...])

Fit SCUM once and return median-combined multi-step forecasts.

predict(y[, exog, axis])

Predict the next horizon steps ahead.

reset([keep])

Reset the object to a clean post-init state.

set_fit_request(*[, axis, exog])

Configure whether metadata should be requested to be passed to the fit method.

set_params(**params)

Set the parameters of this estimator.

set_predict_request(*[, axis, exog])

Configure whether metadata should be requested to be passed to the predict method.

set_tags(**tag_dict)

Set dynamic tags to given values.
clone(random_state=None)[source]

Obtain a clone of the object with the same hyperparameters.

A clone is a different object without shared references, in post-init state. This function is equivalent to returning sklearn.clone of self. Equal in value to type(self)(**self.get_params(deep=False)).

Parameters:
random_stateint, RandomState instance, or None, default=None

Sets the random state of the clone. If None, the random state is not set. If int, random_state is the seed used by the random number generator. If RandomState instance, random_state is the random number generator.

Returns:
estimatorobject

Instance of type(self), clone of self (see above)

fit(y, exog=None, axis=1)[source]

Fit forecaster to series y.

Fit a forecaster to predict self.horizon steps ahead using y.

Parameters:
ynp.ndarray

A time series on which to learn a forecaster to predict horizon ahead.

exognp.ndarray, default =None

Optional target-time exogenous values aligned with y.

Returns:
self

Fitted BaseForecaster.

forecast(y, exog=None, axis=1) → float[source]

Forecast the next horizon steps ahead of y.

By default this is simply fit followed by predict.

Parameters:
ynp.ndarray

A time series to predict the next horizon value for. Must be of shape (n_channels, n_timepoints) if a multivariate time series.

exognp.ndarray, default =None

Optional target-time exogenous values aligned with y.

Returns:
float

single prediction self.horizon steps ahead of y.

classmethod get_class_tag(tag_name, raise_error=True, tag_value_default=None)[source]

Get tag value from estimator class (only class tags).

Parameters:
tag_namestr

Name of tag value.

raise_errorbool, default=True

Whether a ValueError is raised when the tag is not found.

tag_value_defaultany type, default=None

Default/fallback value if tag is not found and error is not raised.

Returns:
tag_value

Value of the tag_name tag in cls. If not found, returns an error if raise_error is True, otherwise it returns tag_value_default.

Raises:
ValueError

if raise_error is True and tag_name is not in self.get_tags().keys()

Examples

>>> from aeon.classification import DummyClassifier
>>> DummyClassifier.get_class_tag("capability:multivariate")
True
classmethod get_class_tags()[source]

Get class tags from estimator class and all its parent classes.

Returns:
collected_tagsdict

Dictionary of tag name and tag value pairs. Collected from _tags class attribute via nested inheritance. These are not overridden by dynamic tags set by set_tags or class __init__ calls.

get_fitted_params(deep=True)[source]

Get fitted parameters.

State required:

Requires state to be “fitted”.

Parameters:
deepbool, default=True

If True, will return the fitted parameters for this estimator and contained subobjects that are estimators.

Returns:
fitted_paramsdict

Fitted parameter names mapped to their values.

get_params(deep=True)

Get parameters for this estimator.

Parameters:
deepbool, default=True

If True, will return the parameters for this estimator and contained subobjects that are estimators.

Returns:
paramsdict

Parameter names mapped to their values.

get_tag(tag_name, raise_error=True, tag_value_default=None)[source]

Get tag value from estimator class.

Includes dynamic and overridden tags.

Parameters:
tag_namestr

Name of tag to be retrieved.

raise_errorbool, default=True

Whether a ValueError is raised when the tag is not found.

tag_value_defaultany type, default=None

Default/fallback value if tag is not found and error is not raised.

Returns:
tag_value

Value of the tag_name tag in self. If not found, returns an error if raise_error is True, otherwise it returns tag_value_default.

Raises:
ValueError

if raise_error is True and tag_name is not in self.get_tags().keys()

Examples

>>> from aeon.classification import DummyClassifier
>>> d = DummyClassifier()
>>> d.get_tag("capability:multivariate")
True
get_tags()[source]

Get tags from estimator.

Includes dynamic and overridden tags.

Returns:
collected_tagsdict

Dictionary of tag name and tag value pairs. Collected from _tags class attribute via nested inheritance and then any overridden and new tags from __init__ or set_tags.

iterative_forecast(y, prediction_horizon, exog=None, *, future_exog=None)[source]

Fit SCUM once and return median-combined multi-step forecasts.

predict(y, exog=None, axis=1) → float[source]

Predict the next horizon steps ahead.

Parameters:
ynp.ndarray

A time series to predict the next horizon value for.

exognp.ndarray, default =None

Optional exogenous values for the prediction target. For models fitted with exogenous variables, this should contain the exogenous values needed to make the next prediction.

Returns:
float

single prediction self.horizon steps ahead of y.

reset(keep=None)[source]

Reset the object to a clean post-init state.

After a self.reset() call, self is equal or similar in value to type(self)(**self.get_params(deep=False)), assuming no other attributes were kept using keep.

Detailed behaviour:
removes any object attributes, except:

hyper-parameters (arguments of __init__) object attributes containing double-underscores, i.e., the string “__”

runs __init__ with current values of hyperparameters (result of get_params)

Not affected by the reset are:

object attributes containing double-underscores class and object methods, class attributes any attributes specified in the keep argument

Parameters:
keepNone, str, or list of str, default=None

If None, all attributes are removed except hyperparameters. If str, only the attribute with this name is kept. If list of str, only the attributes with these names are kept.

Returns:
selfobject

Reference to self.

Raises:
TypeError

If ‘keep’ is not a string or a list of strings.

set_fit_request(*, axis: bool | None | str = '$UNCHANGED$', exog: bool | None | str = '$UNCHANGED$') → SCUM

Configure whether metadata should be requested to be passed to the fit method.

Note that this method is only relevant when this estimator is used as a sub-estimator within a meta-estimator and metadata routing is enabled with enable_metadata_routing=True (see sklearn.set_config). Please check the User Guide on how the routing mechanism works.

The options for each parameter are:

  • True: metadata is requested, and passed to fit if provided. The request is ignored if metadata is not provided.

  • False: metadata is not requested and the meta-estimator will not pass it to fit.

  • None: metadata is not requested, and the meta-estimator will raise an error if the user provides it.

  • str: metadata should be passed to the meta-estimator with this given alias instead of the original name.

The default (sklearn.utils.metadata_routing.UNCHANGED) retains the existing request. This allows you to change the request for some parameters and not others.

Added in version 1.3.

Parameters:
axisstr, True, False, or None, default=sklearn.utils.metadata_routing.UNCHANGED

Metadata routing for axis parameter in fit.

exogstr, True, False, or None, default=sklearn.utils.metadata_routing.UNCHANGED

Metadata routing for exog parameter in fit.

Returns:
selfobject

The updated object.

set_params(**params)

Set the parameters of this estimator.

The method works on simple estimators as well as on nested objects (such as Pipeline). The latter have parameters of the form <component>__<parameter> so that it’s possible to update each component of a nested object.

Parameters:
**paramsdict

Estimator parameters.

Returns:
selfestimator instance

Estimator instance.

set_predict_request(*, axis: bool | None | str = '$UNCHANGED$', exog: bool | None | str = '$UNCHANGED$') → SCUM

Configure whether metadata should be requested to be passed to the predict method.

Note that this method is only relevant when this estimator is used as a sub-estimator within a meta-estimator and metadata routing is enabled with enable_metadata_routing=True (see sklearn.set_config). Please check the User Guide on how the routing mechanism works.

The options for each parameter are:

  • True: metadata is requested, and passed to predict if provided. The request is ignored if metadata is not provided.

  • False: metadata is not requested and the meta-estimator will not pass it to predict.

  • None: metadata is not requested, and the meta-estimator will raise an error if the user provides it.

  • str: metadata should be passed to the meta-estimator with this given alias instead of the original name.

The default (sklearn.utils.metadata_routing.UNCHANGED) retains the existing request. This allows you to change the request for some parameters and not others.

Added in version 1.3.

Parameters:
axisstr, True, False, or None, default=sklearn.utils.metadata_routing.UNCHANGED

Metadata routing for axis parameter in predict.

exogstr, True, False, or None, default=sklearn.utils.metadata_routing.UNCHANGED

Metadata routing for exog parameter in predict.

Returns:
selfobject

The updated object.

set_tags(**tag_dict)[source]

Set dynamic tags to given values.

Parameters:
**tag_dictdict

Dictionary of tag name and tag value pairs.

Returns:
selfobject

Reference to self.