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# copyright: hyperactive developers, MIT License (see LICENSE file) |
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import numpy as np |
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from skbase.utils.dependencies import _check_soft_dependencies |
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if _check_soft_dependencies("sktime", severity="none"): |
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from sktime.forecasting.base._delegate import _DelegatedForecaster |
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else: |
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from skbase.base import BaseEstimator as _DelegatedForecaster |
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from hyperactive.experiment.integrations.sktime_forecasting import ( |
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SktimeForecastingExperiment, |
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) |
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class ForecastingOptCV(_DelegatedForecaster): |
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"""Tune an sktime forecaster via any optimizer in the hyperactive API. |
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Parameters |
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---------- |
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forecaster : sktime forecaster, BaseForecaster instance or interface compatible |
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The forecaster to tune, must implement the sktime forecaster interface. |
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optimizer : hyperactive BaseOptimizer |
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The optimizer to be used for hyperparameter search. |
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cv : sktime BaseSplitter descendant |
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determines split of ``y`` and possibly ``X`` into test and train folds |
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y is always split according to ``cv``, see above |
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if ``cv_X`` is not passed, ``X`` splits are subset to ``loc`` equal to ``y`` |
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if ``cv_X`` is passed, ``X`` is split according to ``cv_X`` |
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strategy : {"refit", "update", "no-update_params"}, optional, default="refit" |
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defines the ingestion mode when the forecaster sees new data when window expands |
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"refit" = forecaster is refitted to each training window |
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"update" = forecaster is updated with training window data, in sequence provided |
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"no-update_params" = fit to first training window, re-used without fit or update |
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update_behaviour : str, optional, default = "full_refit" |
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one of {"full_refit", "inner_only", "no_update"} |
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behaviour of the forecaster when calling update |
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"full_refit" = both tuning parameters and inner estimator refit on all data seen |
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"inner_only" = tuning parameters are not re-tuned, inner estimator is updated |
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"no_update" = neither tuning parameters nor inner estimator are updated |
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scoring : sktime metric (BaseMetric), str, or callable, optional (default=None) |
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scoring metric to use in tuning the forecaster |
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* sktime metric objects (BaseMetric) descendants can be searched |
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with the ``registry.all_estimators`` search utility, |
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for instance via ``all_estimators("metric", as_dataframe=True)`` |
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* If callable, must have signature |
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``(y_true: 1D np.ndarray, y_pred: 1D np.ndarray) -> float``, |
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assuming np.ndarrays being of the same length, and lower being better. |
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Metrics in sktime.performance_metrics.forecasting are all of this form. |
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* If str, uses registry.resolve_alias to resolve to one of the above. |
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Valid strings are valid registry.craft specs, which include |
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string repr-s of any BaseMetric object, e.g., "MeanSquaredError()"; |
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and keys of registry.ALIAS_DICT referring to metrics. |
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* If None, defaults to MeanAbsolutePercentageError() |
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refit : bool, optional (default=True) |
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True = refit the forecaster with the best parameters on the entire data in fit |
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False = no refitting takes place. The forecaster cannot be used to predict. |
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This is to be used to tune the hyperparameters, and then use the estimator |
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as a parameter estimator, e.g., via get_fitted_params or PluginParamsForecaster. |
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error_score : "raise" or numeric, default=np.nan |
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Value to assign to the score if an exception occurs in estimator fitting. If set |
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to "raise", the exception is raised. If a numeric value is given, |
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FitFailedWarning is raised. |
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cv_X : sktime BaseSplitter descendant, optional |
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determines split of ``X`` into test and train folds |
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default is ``X`` being split to identical ``loc`` indices as ``y`` |
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if passed, must have same number of splits as ``cv`` |
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backend : string, by default "None". |
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Parallelization backend to use for runs. |
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Runs parallel evaluate if specified and ``strategy="refit"``. |
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- "None": executes loop sequentially, simple list comprehension |
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- "loky", "multiprocessing" and "threading": uses ``joblib.Parallel`` loops |
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- "joblib": custom and 3rd party ``joblib`` backends, e.g., ``spark`` |
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- "dask": uses ``dask``, requires ``dask`` package in environment |
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- "dask_lazy": same as "dask", |
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but changes the return to (lazy) ``dask.dataframe.DataFrame``. |
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- "ray": uses ``ray``, requires ``ray`` package in environment |
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Recommendation: Use "dask" or "loky" for parallel evaluate. |
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"threading" is unlikely to see speed ups due to the GIL and the serialization |
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backend (``cloudpickle``) for "dask" and "loky" is generally more robust |
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than the standard ``pickle`` library used in "multiprocessing". |
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backend_params : dict, optional |
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additional parameters passed to the backend as config. |
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Directly passed to ``utils.parallel.parallelize``. |
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Valid keys depend on the value of ``backend``: |
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- "None": no additional parameters, ``backend_params`` is ignored |
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- "loky", "multiprocessing" and "threading": default ``joblib`` backends |
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any valid keys for ``joblib.Parallel`` can be passed here, e.g., ``n_jobs``, |
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with the exception of ``backend`` which is directly controlled by ``backend``. |
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If ``n_jobs`` is not passed, it will default to ``-1``, other parameters |
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will default to ``joblib`` defaults. |
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- "joblib": custom and 3rd party ``joblib`` backends, e.g., ``spark``. |
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any valid keys for ``joblib.Parallel`` can be passed here, e.g., ``n_jobs``, |
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``backend`` must be passed as a key of ``backend_params`` in this case. |
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If ``n_jobs`` is not passed, it will default to ``-1``, other parameters |
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will default to ``joblib`` defaults. |
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- "dask": any valid keys for ``dask.compute`` can be passed, |
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e.g., ``scheduler`` |
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- "ray": The following keys can be passed: |
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- "ray_remote_args": dictionary of valid keys for ``ray.init`` |
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- "shutdown_ray": bool, default=True; False prevents ``ray`` from shutting |
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down after parallelization. |
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- "logger_name": str, default="ray"; name of the logger to use. |
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- "mute_warnings": bool, default=False; if True, suppresses warnings |
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Example |
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------- |
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Tuning an sktime forecaster via grid search |
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1. defining the tuned estimator: |
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>>> from sktime.forecasting.naive import NaiveForecaster |
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>>> from sktime.split import ExpandingWindowSplitter |
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>>> from hyperactive.integrations.sktime import ForecastingOptCV |
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>>> from hyperactive.opt import GridSearchSk as GridSearch |
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>>> |
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>>> param_grid = {"strategy": ["mean", "last", "drift"]} |
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>>> tuned_naive = ForecastingOptCV( |
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... NaiveForecaster(), |
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... GridSearch(param_grid), |
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... cv=ExpandingWindowSplitter( |
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... initial_window=12, step_length=3, fh=range(1, 13) |
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... ), |
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... ) |
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2. fitting the tuned estimator: |
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>>> from sktime.datasets import load_airline |
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>>> from sktime.split import temporal_train_test_split |
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>>> y = load_airline() |
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>>> y_train, y_test = temporal_train_test_split(y, test_size=12) |
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>>> |
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>>> tuned_naive.fit(y_train, fh=range(1, 13)) |
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ForecastingOptCV(...) |
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>>> y_pred = tuned_naive.predict() |
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3. obtaining best parameters and best estimator |
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>>> best_params = tuned_naive.best_params_ |
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>>> best_estimator = tuned_naive.best_forecaster_ |
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""" |
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_tags = { |
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"authors": "fkiraly", |
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"maintainers": "fkiraly", |
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"python_dependencies": "sktime", |
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} |
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# attribute for _DelegatedForecaster, which then delegates |
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# all non-overridden methods are same as of getattr(self, _delegate_name) |
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# see further details in _DelegatedForecaster docstring |
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_delegate_name = "best_forecaster_" |
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def __init__( |
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self, |
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forecaster, |
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optimizer, |
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cv, |
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strategy="refit", |
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update_behaviour="full_refit", |
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scoring=None, |
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refit=True, |
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error_score=np.nan, |
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cv_X=None, |
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backend=None, |
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backend_params=None, |
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): |
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self.forecaster = forecaster |
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self.optimizer = optimizer |
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self.cv = cv |
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self.strategy = strategy |
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self.update_behaviour = update_behaviour |
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self.scoring = scoring |
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self.refit = refit |
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self.error_score = error_score |
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self.cv_X = cv_X |
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self.backend = backend |
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self.backend_params = backend_params |
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super().__init__() |
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def _fit(self, y, X, fh): |
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"""Fit to training data. |
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Parameters |
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---------- |
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y : pd.Series |
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Target time series to which to fit the forecaster. |
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fh : int, list or np.array, optional (default=None) |
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The forecasters horizon with the steps ahead to to predict. |
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X : pd.DataFrame, optional (default=None) |
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Exogenous variables are ignored |
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Returns |
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------- |
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self : returns an instance of self. |
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""" |
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from sktime.utils.validation.forecasting import check_scoring |
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forecaster = self.forecaster.clone() |
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scoring = check_scoring(self.scoring, obj=self) |
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# scoring_name = f"test_{scoring.name}" |
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experiment = SktimeForecastingExperiment( |
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forecaster=forecaster, |
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scoring=scoring, |
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cv=self.cv, |
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X=X, |
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y=y, |
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strategy=self.strategy, |
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error_score=self.error_score, |
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cv_X=self.cv_X, |
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backend=self.backend, |
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backend_params=self.backend_params, |
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) |
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optimizer = self.optimizer.clone() |
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optimizer.set_params(experiment=experiment) |
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best_params = optimizer.solve() |
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self.best_params_ = best_params |
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self.best_forecaster_ = forecaster.set_params(**best_params) |
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# Refit model with best parameters. |
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if self.refit: |
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self.best_forecaster_.fit(y=y, X=X, fh=fh) |
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return self |
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def _predict(self, fh, X): |
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"""Forecast time series at future horizon. |
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private _predict containing the core logic, called from predict |
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State required: |
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Requires state to be "fitted". |
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Accesses in self: |
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Fitted model attributes ending in "_" |
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self.cutoff |
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Parameters |
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---------- |
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fh : guaranteed to be ForecastingHorizon or None, optional (default=None) |
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The forecasting horizon with the steps ahead to to predict. |
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If not passed in _fit, guaranteed to be passed here |
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X : pd.DataFrame, optional (default=None) |
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Exogenous time series |
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Returns |
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------- |
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y_pred : pd.Series |
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Point predictions |
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""" |
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if not self.refit: |
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raise RuntimeError( |
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f"In {self.__class__.__name__}, refit must be True to make predictions," |
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f" but found refit=False. If refit=False, {self.__class__.__name__} can" |
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" be used only to tune hyper-parameters, as a parameter estimator." |
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) |
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return super()._predict(fh=fh, X=X) |
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def _update(self, y, X=None, update_params=True): |
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"""Update time series to incremental training data. |
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Parameters |
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---------- |
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y : guaranteed to be of a type in self.get_tag("y_inner_mtype") |
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Time series with which to update the forecaster. |
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if self.get_tag("scitype:y")=="univariate": |
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guaranteed to have a single column/variable |
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if self.get_tag("scitype:y")=="multivariate": |
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guaranteed to have 2 or more columns |
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if self.get_tag("scitype:y")=="both": no restrictions apply |
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X : optional (default=None) |
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guaranteed to be of a type in self.get_tag("X_inner_mtype") |
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Exogeneous time series for the forecast |
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update_params : bool, optional (default=True) |
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whether model parameters should be updated |
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Returns |
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------- |
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self : reference to self |
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""" |
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update_behaviour = self.update_behaviour |
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303
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if update_behaviour == "full_refit": |
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super()._update(y=y, X=X, update_params=update_params) |
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elif update_behaviour == "inner_only": |
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306
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self.best_forecaster_.update(y=y, X=X, update_params=update_params) |
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elif update_behaviour == "no_update": |
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308
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self.best_forecaster_.update(y=y, X=X, update_params=False) |
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else: |
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raise ValueError( |
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'update_behaviour must be one of "full_refit", "inner_only",' |
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312
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f' or "no_update", but found {update_behaviour}' |
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) |
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return self |
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315
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316
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@classmethod |
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def get_test_params(cls, parameter_set="default"): |
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"""Return testing parameter settings for the estimator. |
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319
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320
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Parameters |
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---------- |
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|
parameter_set : str, default="default" |
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323
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|
Name of the set of test parameters to return, for use in tests. If no |
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324
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special parameters are defined for a value, will return ``"default"`` set. |
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325
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|
|
|
|
326
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|
Returns |
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327
|
|
|
------- |
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328
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|
|
params : dict or list of dict |
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329
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""" |
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330
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from sktime.forecasting.naive import NaiveForecaster |
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331
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from sktime.forecasting.trend import PolynomialTrendForecaster |
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332
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|
from sktime.performance_metrics.forecasting import ( |
|
333
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|
|
MeanAbsolutePercentageError, |
|
334
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|
mean_absolute_percentage_error, |
|
335
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) |
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336
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|
|
from sktime.split import SingleWindowSplitter |
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337
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|
|
338
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|
|
from hyperactive.opt.gfo import HillClimbing |
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from hyperactive.opt.gridsearch import GridSearchSk |
|
340
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from hyperactive.opt.random_search import RandomSearchSk |
|
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|
|
|
|
|
342
|
|
|
params_gridsearch = { |
|
343
|
|
|
"forecaster": NaiveForecaster(strategy="mean"), |
|
344
|
|
|
"cv": SingleWindowSplitter(fh=1), |
|
345
|
|
|
"optimizer": GridSearchSk(param_grid={"window_length": [2, 5]}), |
|
346
|
|
|
"scoring": MeanAbsolutePercentageError(symmetric=True), |
|
347
|
|
|
} |
|
348
|
|
|
params_randomsearch = { |
|
349
|
|
|
"forecaster": PolynomialTrendForecaster(), |
|
350
|
|
|
"cv": SingleWindowSplitter(fh=1), |
|
351
|
|
|
"optimizer": RandomSearchSk(param_distributions={"degree": [1, 2]}), |
|
352
|
|
|
"scoring": mean_absolute_percentage_error, |
|
353
|
|
|
"update_behaviour": "inner_only", |
|
354
|
|
|
} |
|
355
|
|
|
params_hillclimb = { |
|
356
|
|
|
"forecaster": NaiveForecaster(strategy="mean"), |
|
357
|
|
|
"cv": SingleWindowSplitter(fh=1), |
|
358
|
|
|
"optimizer": HillClimbing( |
|
359
|
|
|
search_space={"window_length": [2, 5]}, |
|
360
|
|
|
n_iter=10, |
|
361
|
|
|
n_neighbours=5, |
|
362
|
|
|
), |
|
363
|
|
|
"scoring": "MeanAbsolutePercentageError(symmetric=True)", |
|
364
|
|
|
"update_behaviour": "no_update", |
|
365
|
|
|
} |
|
366
|
|
|
return [params_gridsearch, params_randomsearch, params_hillclimb] |
|
367
|
|
|
|