def make(N_part=100, seed=None):
    random = np.random.RandomState(seed=seed)
    (mass_dm, pos_dm) = mock_dm_halo(N_part=N_part)
    vel_dm = random.random_sample(size=(N_part, 3))
    return (mass_dm, pos_dm, vel_dm)
def make(N_part=100, seed=None):
    random = np.random.RandomState(seed=seed)
    (mass_dm, pos_dm) = mock_dm_halo(N_part=N_part)
    vel_dm = random.random_sample(size=(N_part, 3))
    return (mass_dm, pos_dm, vel_dm)