Function test_psd_oversampling

lib/matplotlib/tests/test_mlab.py:1027–1037

Test the case len(x) < NFFT for psd().

()

def test_psd_oversampling():
    """Test the case len(x) < NFFT for psd()."""
    u = np.array([0, 1, 2, 3, 1, 2, 1])
    dt = 1.0
    Su = np.abs(np.fft.fft(u) * dt)**2 / (dt * u.size)
    P, f = mlab.psd(u, NFFT=u.size*2, Fs=1/dt, window=mlab.window_none,
                    detrend=mlab.detrend_none, noverlap=0, pad_to=None,
                    scale_by_freq=None,
                    sides='onesided')
    Su_1side = np.append([Su[0]], Su[1:4] + Su[4:][::-1])
    assert_almost_equal(np.sum(P), np.sum(Su_1side))  # same energy