Change code to prevent diffdock creating *.npy when just checking usage

[mainguyenanhvu]

Dear authors,

I found that utils/so3.py automatically created running files even in the case of checking usage at https://github.com/gcorso/DiffDock/blob/main/utils/so3.py#L45:

if os.path.exists('.so3_omegas_array4.npy'):
    _omegas_array = np.load('.so3_omegas_array4.npy')
    _cdf_vals = np.load('.so3_cdf_vals4.npy')
    _score_norms = np.load('.so3_score_norms4.npy')
    _exp_score_norms = np.load('.so3_exp_score_norms4.npy')
else:
    _eps_array = 10 ** np.linspace(np.log10(MIN_EPS), np.log10(MAX_EPS), N_EPS)
    _omegas_array = np.linspace(0, np.pi, X_N + 1)[1:]

    _exp_vals = np.asarray([_expansion(_omegas_array, eps) for eps in _eps_array])
    _pdf_vals = np.asarray([_density(_exp, _omegas_array, marginal=True) for _exp in _exp_vals])
    _cdf_vals = np.asarray([_pdf.cumsum() / X_N * np.pi for _pdf in _pdf_vals])
    _score_norms = np.asarray([_score(_exp_vals[i], _omegas_array, _eps_array[i]) for i in range(len(_eps_array))])

    _exp_score_norms = np.sqrt(np.sum(_score_norms**2 * _pdf_vals, axis=1) / np.sum(_pdf_vals, axis=1) / np.pi)

    np.save('.so3_omegas_array4.npy', _omegas_array)
    np.save('.so3_cdf_vals4.npy', _cdf_vals)
    np.save('.so3_score_norms4.npy', _score_norms)
    np.save('.so3_exp_score_norms4.npy', _exp_score_norms)

and at https://github.com/gcorso/DiffDock/blob/main/utils/torus.py#L31.

if os.path.exists('.p.npy'):
    p_ = np.load('.p.npy')
    score_ = np.load('.score.npy')
else:
    p_ = p(x, sigma[:, None], N=100)
    np.save('.p.npy', p_)

    eps = np.finfo(p_.dtype).eps
    score_ = grad(x, sigma[:, None], N=100) / (p_ + eps)
    np.save('.score.npy', score_)

I think it will be better to run it only when we actually execute with inputs instead of importing. This situation creates files in unexpected directories just because users check usage.