TheAlgorithms/Python · error · ValueError

partitions can not > number_of_bytes!

Error message

partitions can not > number_of_bytes!

What it means

Raised by allocation_num when the requested number of partitions exceeds number_of_bytes. With floor division each partition would get 0 bytes, producing empty/degenerate ranges, so the function refuses. The positive-partition check at line 33 runs first, so this error only fires for partitions >= 1 that are simply too numerous.

Source

Thrown at maths/allocation_number.py:35

    :return: list of bytes to be assigned to each worker thread

    >>> allocation_num(16647, 4)
    ['1-4161', '4162-8322', '8323-12483', '12484-16647']
    >>> allocation_num(50000, 5)
    ['1-10000', '10001-20000', '20001-30000', '30001-40000', '40001-50000']
    >>> allocation_num(888, 999)
    Traceback (most recent call last):
        ...
    ValueError: partitions can not > number_of_bytes!
    >>> allocation_num(888, -4)
    Traceback (most recent call last):
        ...
    ValueError: partitions must be a positive number!
    """
    if partitions <= 0:
        raise ValueError("partitions must be a positive number!")
    if partitions > number_of_bytes:
        raise ValueError("partitions can not > number_of_bytes!")
    bytes_per_partition = number_of_bytes // partitions
    allocation_list = []
    for i in range(partitions):
        start_bytes = i * bytes_per_partition + 1
        end_bytes = (
            number_of_bytes if i == partitions - 1 else (i + 1) * bytes_per_partition
        )
        allocation_list.append(f"{start_bytes}-{end_bytes}")
    return allocation_list


if __name__ == "__main__":
    import doctest

    doctest.testmod()

View on GitHub (pinned to f5988cc097)

Solutions

1. Cap partitions at number_of_bytes: partitions = min(partitions, number_of_bytes).
2. Derive partitions from the size instead of a fixed constant, e.g. partitions = max(1, min(requested, number_of_bytes)).
3. Add a call-site assertion so oversized partition requests fail with your own clearer error.

Example fix

# before
ranges = allocation_num(888, 999)

# after
ranges = allocation_num(888, min(999, 888))  # cap at total size

partitions = min(int(partitions), number_of_bytes)
if partitions < 1:
    raise ValueError('partitions must be >= 1')
ranges = allocation_num(number_of_bytes, partitions)

When it happens

Trigger: Calling allocation_num(888, 999) - any call where 1 <= partitions <= 0-edge is fine but partitions > number_of_bytes raises. Minimum viable input is partitions == number_of_bytes (each chunk gets 1 byte).

Common situations: Auto-scaling split counts from a target chunk size without bounding by total size, hardcoding partition counts for small test files, or unit-of-measure confusion (KB chunk count vs byte total).

Related errors

• partitions must be a positive number!
• Limit for the Catalan sequence must be ≥ 0
• Number should not be negative.
• Negative arguments are not supported
• the value of input must be a natural number

AI-assisted analysis of TheAlgorithms/Python@f5988cc097 (2026-08-14). Data as JSON: /api/errors/5cbbe12de9759272. Report an issue: GitHub.