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cell_connection_probability

Module that calculates cell connection probabilities and posterior probabilities.

CellConnectionProbabilityEstimation

Bases: Component

Estimates the cell connection probabilities and posterior probabilities for each grid tile. Cell connection probabilities are calculated based on footprint per grid. Posterior probabilities are calculated based on the cell connection probabilities and grid prior probabilities.

This class reads in cell footprint estimation and the grid model wit prior probabilities. The output is a DataFrame that represents cell connection probabilities and posterior probabilities for each cell and grid id combination for a given date.

Source code in multimno/components/execution/cell_connection_probability/cell_connection_probability.py
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class CellConnectionProbabilityEstimation(Component):
    """
    Estimates the cell connection probabilities and posterior probabilities for each grid tile.
    Cell connection probabilities are calculated based on footprint per grid.
    Posterior probabilities are calculated based on the cell connection probabilities
    and grid prior probabilities.

    This class reads in cell footprint estimation and the grid model wit prior probabilities.
    The output is a DataFrame that represents cell connection probabilities and
     posterior probabilities for each cell and grid id combination for a given date.
    """

    COMPONENT_ID = "CellConnectionProbabilityEstimation"

    def __init__(self, general_config_path: str, component_config_path: str) -> None:
        super().__init__(general_config_path, component_config_path)

        self.data_period_start = datetime.datetime.strptime(
            self.config.get(self.COMPONENT_ID, "data_period_start"), "%Y-%m-%d"
        ).date()

        self.data_period_end = datetime.datetime.strptime(
            self.config.get(self.COMPONENT_ID, "data_period_end"), "%Y-%m-%d"
        ).date()

        self.data_period_dates = [
            self.data_period_start + datetime.timedelta(days=i)
            for i in range((self.data_period_end - self.data_period_start).days + 1)
        ]

        self.current_date = None
        self.current_cell_footprint = None
        self.partition_number = self.config.getint(self.COMPONENT_ID, "partition_number")

    def initalize_data_objects(self):

        self.clear_destination_directory = self.config.getboolean(self.COMPONENT_ID, "clear_destination_directory")

        # Input
        self.input_data_objects = {}
        self.use_land_use_prior = self.config.getboolean(self.COMPONENT_ID, "use_land_use_prior")

        inputs = {
            "cell_footprint_data_silver": SilverCellFootprintDataObject,
        }

        if self.use_land_use_prior:
            inputs["enriched_grid_data_silver"] = SilverEnrichedGridDataObject

        for key, value in inputs.items():
            path = self.config.get(CONFIG_SILVER_PATHS_KEY, key)
            if check_if_data_path_exists(self.spark, path):
                self.input_data_objects[value.ID] = value(self.spark, path)
            else:
                self.logger.warning(f"Expected path {path} to exist but it does not")
                raise ValueError(f"Invalid path for {value.ID} in component {self.COMPONENT_ID} initialization")

        # Output
        self.output_data_objects = {}
        silver_cell_probabilities_path = self.config.get(
            CONFIG_SILVER_PATHS_KEY, "cell_connection_probabilities_data_silver"
        )

        if self.clear_destination_directory:
            delete_file_or_folder(self.spark, silver_cell_probabilities_path)

        self.output_data_objects[SilverCellConnectionProbabilitiesDataObject.ID] = (
            SilverCellConnectionProbabilitiesDataObject(
                self.spark,
                silver_cell_probabilities_path,
            )
        )

    @get_execution_stats
    def execute(self):
        self.logger.info(f"Starting {self.COMPONENT_ID}...")
        self.read()
        for current_date in self.data_period_dates:

            self.logger.info(f"Processing cell footprint for {current_date.strftime('%Y-%m-%d')}")

            self.current_date = current_date

            self.current_cell_footprint = self.input_data_objects[SilverCellFootprintDataObject.ID].df.filter(
                (F.make_date(F.col(ColNames.year), F.col(ColNames.month), F.col(ColNames.day)) == F.lit(current_date))
            )

            self.transform()
            self.write()
            self.spark.catalog.clearCache()
        self.logger.info(f"Finished {self.COMPONENT_ID}")

    def transform(self):
        self.logger.info(f"Transform method {self.COMPONENT_ID}")

        cell_footprint_df = self.current_cell_footprint

        # Calculate the cell connection probabilities

        window_spec = Window.partitionBy(ColNames.year, ColNames.month, ColNames.day, ColNames.grid_id)

        cell_conn_probs_df = cell_footprint_df.withColumn(
            ColNames.cell_connection_probability,
            F.col(ColNames.signal_dominance) / F.sum(ColNames.signal_dominance).over(window_spec),
        )
        # Calculate the posterior probabilities

        if self.use_land_use_prior:
            grid_model_df = self.input_data_objects[SilverEnrichedGridDataObject.ID].df.select(
                ColNames.grid_id, ColNames.prior_probability
            )
            cell_conn_probs_df = cell_conn_probs_df.join(grid_model_df, on=ColNames.grid_id)
            cell_conn_probs_df = cell_conn_probs_df.withColumn(
                ColNames.posterior_probability,
                F.col(ColNames.cell_connection_probability) * F.col(ColNames.prior_probability),
            )

        elif not self.use_land_use_prior:
            cell_conn_probs_df = cell_conn_probs_df.withColumn(
                ColNames.posterior_probability,
                F.col(ColNames.cell_connection_probability),
            )

        # Normalize the posterior probabilities

        window_spec = Window.partitionBy(ColNames.year, ColNames.month, ColNames.day, ColNames.cell_id)

        cell_conn_probs_df = cell_conn_probs_df.withColumn(
            ColNames.posterior_probability,
            F.col(ColNames.posterior_probability) / F.sum(ColNames.posterior_probability).over(window_spec),
        )

        cell_conn_probs_df = utils.apply_schema_casting(
            cell_conn_probs_df, SilverCellConnectionProbabilitiesDataObject.SCHEMA
        )
        cell_conn_probs_df = cell_conn_probs_df.coalesce(self.partition_number)

        self.output_data_objects[SilverCellConnectionProbabilitiesDataObject.ID].df = cell_conn_probs_df