test_xrft.py 文件源码

def test_isotropic_ps_slope(N=512, dL=1., amp=1e1, s=-3.):
    """Test the spectral slope of isotropic power spectrum."""

    theta = xr.DataArray(_synthetic_field(N, dL, amp, s),
                        dims=['y', 'x'],
                        coords={'y':range(N), 'x':range(N)})
    iso_ps = xrft.isotropic_powerspectrum(theta, detrend='constant',
                                        density=True)
    npt.assert_almost_equal(np.ma.masked_invalid(iso_ps[1:]).mask.sum(), 0.)
    y_fit, a, b = xrft.fit_loglog(iso_ps.freq_r.values[4:],
                                iso_ps.values[4:])

    npt.assert_allclose(a, s, atol=.1)