stl_decomposer =============================================================================== .. py:module:: evalml.pipelines.components.transformers.preprocessing.stl_decomposer .. autoapi-nested-parse:: Component that removes trends and seasonality from time series using STL. Module Contents --------------- Classes Summary ~~~~~~~~~~~~~~~ .. autoapisummary:: evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer Contents ~~~~~~~~~~~~~~~~~~~ .. py:class:: STLDecomposer(time_index: str = None, degree: int = 1, seasonal_period: int = 7, random_seed: int = 0, **kwargs) Removes trends and seasonality from time series using the STL algorithm. https://www.statsmodels.org/dev/generated/statsmodels.tsa.seasonal.STL.html :param time_index: Specifies the name of the column in X that provides the datetime objects. Defaults to None. :type time_index: str :param degree: Not currently used. STL 3x "degree-like" values. None are able to be set at this time. Defaults to 1. :type degree: int :param seasonal_period: The number of entries in the time series data that corresponds to one period of a cyclic signal. For instance, if data is known to possess a weekly seasonal signal, and if the data is daily data, seasonal_period should be 7. For daily data with a yearly seasonal signal, seasonal_period should be 365. For compatibility with the underlying STL algorithm, must be odd. If an even number is provided, the next, highest odd number will be used. Defaults to 7. :type seasonal_period: int :param random_seed: Seed for the random number generator. Defaults to 0. :type random_seed: int **Attributes** .. list-table:: :widths: 15 85 :header-rows: 0 * - **hyperparameter_ranges** - None * - **invalid_frequencies** - ['SM', 'BM', 'SMS', 'BMS', 'BQ', 'BQS', 'T', 'S', 'L', 'U', 'N', 'A', 'BA', 'AS', 'BAS', 'BH'] * - **modifies_features** - False * - **modifies_target** - True * - **name** - STL Decomposer * - **needs_fitting** - True * - **training_only** - False **Methods** .. autoapisummary:: :nosignatures: evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.clone evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.default_parameters evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.describe evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.determine_periodicity evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.fit evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.fit_transform evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.get_trend_dataframe evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.inverse_transform evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.is_freq_valid evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.load evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.parameters evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.plot_decomposition evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.save evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.set_seasonal_period evalml.pipelines.components.transformers.preprocessing.stl_decomposer.STLDecomposer.transform .. py:method:: clone(self) Constructs a new component with the same parameters and random state. :returns: A new instance of this component with identical parameters and random state. .. py:method:: default_parameters(cls) Returns the default parameters for this component. Our convention is that Component.default_parameters == Component().parameters. :returns: Default parameters for this component. :rtype: dict .. py:method:: describe(self, print_name=False, return_dict=False) Describe a component and its parameters. :param print_name: whether to print name of component :type print_name: bool, optional :param return_dict: whether to return description as dictionary in the format {"name": name, "parameters": parameters} :type return_dict: bool, optional :returns: Returns dictionary if return_dict is True, else None. :rtype: None or dict .. py:method:: determine_periodicity(self, X: pandas.DataFrame, y: pandas.Series, method: str = 'autocorrelation') Function that uses autocorrelative methods to determine the first, signficant period of the seasonal signal. :param X: The feature data of the time series problem. :type X: pandas.DataFrame :param y: The target data of a time series problem. :type y: pandas.Series :param method: Either "autocorrelation" or "partial-autocorrelation". The method by which to determine the first period of the seasonal part of the target signal. "partial-autocorrelation" should currently not be used. Defaults to "autocorrelation". :type method: str :returns: The integer numbers of entries in time series data over which the seasonal part of the target data repeats. If the time series data is in days, then this is the number of days that it takes the target's seasonal signal to repeat. Note: the target data can contain multiple seasonal signals. This function will only return the first, and thus, shortest period. E.g. if the target has both weekly and yearly seasonality, the function will only return "7" and not return "365". If no period is detected, returns [None]. :rtype: (list[int]) .. py:method:: fit(self, X: pandas.DataFrame, y: pandas.Series = None) -> STLDecomposer Fits the STLDecomposer and determine the seasonal signal. Instantiates a statsmodels STL decompose object with the component's stored parameters and fits it. Since the statsmodels object does not fit the sklearn api, it is not saved during __init__() in _component_obj and will be re-instantiated each time fit is called. To emulate the sklearn API, when the STL decomposer is fit, the full seasonal component, a single period sample of the seasonal component, the full trend-cycle component and the residual are saved. y(t) = S(t) + T(t) + R(t) :param X: Conditionally used to build datetime index. :type X: pd.DataFrame, optional :param y: Target variable to detrend and deseasonalize. :type y: pd.Series :returns: self :raises ValueError: If y is None. :raises ValueError: If target data doesn't have DatetimeIndex AND no Datetime features in features data .. py:method:: fit_transform(self, X: pandas.DataFrame, y: pandas.Series = None) -> tuple[pandas.DataFrame, pandas.Series] Removes fitted trend and seasonality from target variable. :param X: Ignored. :type X: pd.DataFrame, optional :param y: Target variable to detrend and deseasonalize. :type y: pd.Series :returns: The first element are the input features returned without modification. The second element is the target variable y with the fitted trend removed. :rtype: tuple of pd.DataFrame, pd.Series .. py:method:: get_trend_dataframe(self, X, y) Return a list of dataframes with 4 columns: signal, trend, seasonality, residual. :param X: Input data with time series data in index. :type X: pd.DataFrame :param y: Target variable data provided as a Series for univariate problems or a DataFrame for multivariate problems. :type y: pd.Series or pd.DataFrame :returns: Each DataFrame contains the columns "signal", "trend", "seasonality" and "residual," with the latter 3 column values being the decomposed elements of the target data. The "signal" column is simply the input target signal but reindexed with a datetime index to match the input features. :rtype: list of pd.DataFrame :raises TypeError: If X does not have time-series data in the index. :raises ValueError: If time series index of X does not have an inferred frequency. :raises ValueError: If the forecaster associated with the detrender has not been fit yet. :raises TypeError: If y is not provided as a pandas Series or DataFrame. .. py:method:: inverse_transform(self, y_t: pandas.Series) -> tuple[pandas.DataFrame, pandas.Series] Adds back fitted trend and seasonality to target variable. The STL trend is projected to cover the entire requested target range, then added back into the signal. Then, the seasonality is projected forward to and added back into the signal. :param y_t: Target variable. :type y_t: pd.Series :returns: The first element are the input features returned without modification. The second element is the target variable y with the trend and seasonality added back in. :rtype: tuple of pd.DataFrame, pd.Series :raises ValueError: If y is None. .. py:method:: is_freq_valid(self, freq: str) :classmethod: Determines if the given string represents a valid frequency for this decomposer. :param freq: A frequency to validate. See the pandas docs at https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases for options. :type freq: str :returns: boolean representing whether the frequency is valid or not. .. py:method:: load(file_path) :staticmethod: Loads component at file path. :param file_path: Location to load file. :type file_path: str :returns: ComponentBase object .. py:method:: parameters(self) :property: Returns the parameters which were used to initialize the component. .. py:method:: plot_decomposition(self, X: pandas.DataFrame, y: pandas.Series, show: bool = False) -> tuple[matplotlib.pyplot.Figure, list] Plots the decomposition of the target signal. :param X: Input data with time series data in index. :type X: pd.DataFrame :param y: Target variable data provided as a Series for univariate problems or a DataFrame for multivariate problems. :type y: pd.Series or pd.DataFrame :param show: Whether to display the plot or not. Defaults to False. :type show: bool :returns: The figure and axes that have the decompositions plotted on them :rtype: matplotlib.pyplot.Figure, list[matplotlib.pyplot.Axes] .. py:method:: save(self, file_path, pickle_protocol=cloudpickle.DEFAULT_PROTOCOL) Saves component at file path. :param file_path: Location to save file. :type file_path: str :param pickle_protocol: The pickle data stream format. :type pickle_protocol: int .. py:method:: set_seasonal_period(self, X: pandas.DataFrame, y: pandas.Series) Function to set the component's seasonal period based on the target's seasonality. :param X: The feature data of the time series problem. :type X: pandas.DataFrame :param y: The target data of a time series problem. :type y: pandas.Series .. py:method:: transform(self, X: pandas.DataFrame, y: pandas.Series = None) -> tuple[pandas.DataFrame, pandas.Series] Transforms the target data by removing the STL trend and seasonality. Uses an ARIMA model to project forward the addititve trend and removes it. Then, utilizes the first period's worth of seasonal data determined in the .fit() function to extrapolate the seasonal signal of the data to be transformed. This seasonal signal is also assumed to be additive and is removed. :param X: Conditionally used to build datetime index. :type X: pd.DataFrame, optional :param y: Target variable to detrend and deseasonalize. :type y: pd.Series :returns: The input features are returned without modification. The target variable y is detrended and deseasonalized. :rtype: tuple of pd.DataFrame, pd.Series :raises ValueError: If target data doesn't have DatetimeIndex AND no Datetime features in features data