@pytest.fixture
def disc_particles(solid_disk):
    'Solid disc without velocities.'
    (mass, pos, vel) = solid_disk(N_part=100)
    return (pos[:, 0], pos[:, 1], pos[:, 2], mass)
Solid disc without velocities.
@pytest.fixture
def disc_particles(solid_disk):
    
    (mass, pos, vel) = solid_disk(N_part=100)
    return (pos[:, 0], pos[:, 1], pos[:, 2], mass)