TST : add test of odd NFFT single sided psd

tacaswell · tacaswell · commit 01d2e6ccc095 · 2015-04-12T12:11:36.000-04:00
diff --git a/lib/matplotlib/tests/test_mlab.py b/lib/matplotlib/tests/test_mlab.py
@@ -2960,8 +2960,17 @@ def test_evaluate_equal_dim_and_num_lt(self):
         np.testing.assert_array_almost_equal(y, y_expected, 7)
 
 
-#*****************************************************************
-#*****************************************************************
+def test_psd_onesided_norm():
+    u = np.array([0, 1, 2, 3, 1, 2, 1])
+    dt = 1.0
+    Su = np.abs(np.fft.fft(u) * dt)**2 / float(dt * u.size)
+    P, f = mlab.psd(u, NFFT=u.size, 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_allclose(P, Su_1side, atol=1e-06)
+
 
 if __name__ == '__main__':
     import nose
