Function to generate hexagonally packed points within a given radius

hexagonal_packed_circle.py

import numpy as np

def hexagon(radius: float, spacing: float) -> np.ndarray:
    """take a circle radius and point spacing and return an 
    [N, 2] shaped array containing the hexagonal-packed points 
    """
    n_points = int(np.ceil(radius / spacing)) * 2
    basis = spacing * np.array([[1, 0], [np.cos(np.pi / 3), np.sin(np.pi / 3)]])
    x, y = np.mgrid[
        -n_points : n_points : (2 * n_points + 1) * 1j,
        -n_points : n_points : (2 * n_points + 1) * 1j,
    ]
    points = (
        x[:, :, np.newaxis] * basis[0] + y[:, :, np.newaxis] * basis[1]
    ).reshape(((2 * n_points + 1) ** 2, -1))

    points_filter = (points ** 2).sum(axis=1) <= (radius ** 2)
    return points[points_filter]