Source code for flwr_datasets.partitioner.square_partitioner

# Copyright 2023 Flower Labs GmbH. All Rights Reserved.
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# Licensed under the Apache License, Version 2.0 (the "License");
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#     http://www.apache.org/licenses/LICENSE-2.0
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"""SquarePartitioner class."""


import numpy as np

from flwr_datasets.partitioner.size_partitioner import SizePartitioner


class SquarePartitioner(SizePartitioner):
    """Partitioner creates partitions of size that are correlated with squared id.

    The amount of data each client gets is correlated with the squared partition ID.
    For instance, if the IDs range from 1 to M, client with ID 1 gets 1 unit of data,
    client 2 gets 4 units, and so on, up to client M which gets M^2 units.

    Parameters
    ----------
    num_partitions : int
        The total number of partitions that the data will be divided into.
    """

    def __init__(self, num_partitions: int) -> None:
        super().__init__(
            num_partitions=num_partitions, partition_id_to_size_fn=np.square
        )
        if num_partitions <= 0:
            raise ValueError("The number of partitions must be greater than zero.")