TheAlgorithms/Python · error · ValueError

vol_hollow_circular_cylinder() only accepts non-negative val

Error message

vol_hollow_circular_cylinder() only accepts non-negative values

What it means

Raised by vol_hollow_circular_cylinder(inner_radius, outer_radius, height) in maths/volume.py when inner_radius, outer_radius or height is negative. This is the first of two guards: it only checks signs; a second guard then enforces outer_radius > inner_radius. The result is pi * (outer**2 - inner**2) * height.

Source

Thrown at maths/volume.py:435

    Traceback (most recent call last):
        ...
    ValueError: vol_hollow_circular_cylinder() only accepts non-negative values
    >>> vol_hollow_circular_cylinder(1, 2, -3)
    Traceback (most recent call last):
        ...
    ValueError: vol_hollow_circular_cylinder() only accepts non-negative values
    >>> vol_hollow_circular_cylinder(2, 1, 3)
    Traceback (most recent call last):
        ...
    ValueError: outer_radius must be greater than inner_radius
    >>> vol_hollow_circular_cylinder(0, 0, 0)
    Traceback (most recent call last):
        ...
    ValueError: outer_radius must be greater than inner_radius
    """
    # Volume - (outer_radius squared - inner_radius squared) * pi * height
    if inner_radius < 0 or outer_radius < 0 or height < 0:
        raise ValueError(
            "vol_hollow_circular_cylinder() only accepts non-negative values"
        )
    if outer_radius <= inner_radius:
        raise ValueError("outer_radius must be greater than inner_radius")
    return pi * (pow(outer_radius, 2) - pow(inner_radius, 2)) * height


def vol_conical_frustum(height: float, radius_1: float, radius_2: float) -> float:
    """
    | Calculate the Volume of a Conical Frustum.
    | Wikipedia reference: https://en.wikipedia.org/wiki/Frustum

    >>> vol_conical_frustum(45, 7, 28)
    48490.482608158454
    >>> vol_conical_frustum(1, 1, 2)
    7.330382858376184
    >>> vol_conical_frustum(1.6, 2.6, 3.6)
    48.7240076620753

View on GitHub (pinned to f5988cc097)

Solutions

Validate all three arguments are >= 0 before the call (and outer > inner to also avoid the second ValueError).
Recompute inner_radius = outer_radius - wall_thickness and clamp/validate the result when thickness data is offset-based.
Check column mapping of your import file if negatives appear systematically.

Example fix

# before
vol = vol_hollow_circular_cylinder(outer_r - wall, outer_r, h)  # negative when wall > outer_r

# after
inner_r = outer_r - wall
if inner_r < 0:
    raise ValueError(f'wall thickness {wall} exceeds outer radius {outer_r}')
vol = vol_hollow_circular_cylinder(inner_r, outer_r, h)

Defensive patterns

Strategy: validation

Validate before calling

if inner_radius < 0 or outer_radius < 0 or height < 0:
    raise ValueError(f'hollow cylinder args must be >= 0: {inner_radius}, {outer_radius}, {height}')
vol = vol_hollow_circular_cylinder(inner_radius, outer_radius, height)

Try / catch

try:
    vol = vol_hollow_circular_cylinder(ir, oR, h)
except ValueError as e:
    raise ValueError(f'bad tube geometry ir={ir}, oR={oR}, h={h}: {e}') from e

Prevention

Validate wall-thickness-derived inner radii before the call.
Check import column mapping when negatives appear systematically.

When it happens

Trigger: Calling vol_hollow_circular_cylinder(-1, 2, 3), (1, -2, 3) or (1, 2, -3); pipe/tube parameters imported with sign errors or swapped-but-negative values.

Common situations: CAD or piping data where wall thickness is stored as a negative offset from the outer radius; measurement files with minus signs from a calibration offset; mixing inner/outer columns in a spreadsheet.

Related errors

AI-assisted analysis of TheAlgorithms/Python@f5988cc097 (2026-08-14). Data as JSON: /api/errors/a20993463ced5934. Report an issue: GitHub.