def test_first_derivative(self):
x0 = np.arange(0, 2.0 * np.pi, 0.01)
xx = []
for x in x0:
if np.random.random() < .3:
xx.append(x)
x0 = np.array(xx)
testf = np.array([np.sin(x) for x in x0])
true_deriv = np.array([np.cos(x) for x in x0])
wwidth = 5
deriv = np.empty_like(x0)
for ix, (wx, wy) in enumerate(zip(sliding_window(x0, width=wwidth, fixed_width=True),
sliding_window(testf, width=wwidth, fixed_width=True))):
x = x0[ix]
coeff = fd_coefficients(x, wx, k=1)
deriv[ix] = coeff.dot(wy)
np.testing.assert_almost_equal(deriv, true_deriv, 6)
def test_sliding_window(self):
n = 0
seq = [1, 2, 3, 4, 5, 6, 7, 8, 9]
width = 2
for ix in sliding_window(seq, width=width, fixed_width=False):
self.assertLessEqual(len(ix), 2 * width + 1)
self.assertGreaterEqual(seq[n], np.min(ix))
self.assertLessEqual(seq[n], np.max(ix))
n += 1
self.assertEqual(n, len(seq), "need n={} == len(seq)=={}".format(n, len(seq)))
def test_sliding_window_fixed_width(self):
n = 0
seq = [1, 2, 3, 4, 5, 6, 7, 8, 9]
width = 2
for ix in sliding_window(seq, width=width, fixed_width=True):
assert len(ix) == 2 * width + 1
assert seq[n] >= np.min(ix)
assert seq[n] <= np.max(ix)
n += 1
assert n == len(seq), "need n={} == len(seq)=={}".format(n, len(seq))
def test_first_derivative(self):
x0 = np.arange(0, 2.0 * np.pi, 0.05)
xx = []
for x in x0:
if np.random.random() < .3:
xx.append(x)
x0 = np.array(xx)
testf = np.array([np.sin(x) for x in x0])
true_deriv = [np.cos(x) for x in x0]
wwidth = 5
deriv = np.empty_like(x0)
for ix, (wx, wy) in enumerate(
zip(sliding_window(x0, width=wwidth, fixed_width=True),
sliding_window(testf, width=wwidth, fixed_width=True))):
x = x0[ix]
coeff = fd_coefficients(x, wx, k=1)
deriv[ix] = coeff.dot(wy)
plt.plot(x0, deriv, 'o')
plt.plot(x0, true_deriv)
plt.show()
print(np.array(deriv) - np.array(true_deriv))