def test_zero_gradient():
"""Test divergence_vorticity when there is no gradient in the field."""
u = np.ones((3, 3)) * units('m/s')
c, v = divergence_vorticity(u,
u,
1 * units.meter,
1 * units.meter,
dim_order='xy')
truth = np.zeros_like(u) / units.sec
assert_array_equal(c, truth)
assert_array_equal(v, truth)
def test_divergence_vorticity():
"""Test of vorticity and divergence calculation for basic case."""
a = np.arange(3)
u = np.c_[a, a, a] * units('m/s')
c, v = divergence_vorticity(u,
u,
1 * units.meter,
1 * units.meter,
dim_order='xy')
true_c = np.ones_like(u) / units.sec
true_v = np.ones_like(u) / units.sec
assert_array_equal(c, true_c)
assert_array_equal(v, true_v)
def test_cv_zero_vorticity():
"""Test divergence_vorticity when there is only divergence."""
a = np.arange(3)
u = np.c_[a, a, a] * units('m/s')
c, v = divergence_vorticity(u,
u.T,
1 * units.meter,
1 * units.meter,
dim_order='xy')
true_c = 2. * np.ones_like(u) / units.sec
true_v = np.zeros_like(u) / units.sec
assert_array_equal(c, true_c)
assert_array_equal(v, true_v)
def test_vorticity_divergence_asym():
"""Test vorticity and divergence calculation with a complicated field."""
u = np.array([[2, 4, 8], [0, 2, 2], [4, 6, 8]]) * units('m/s')
v = np.array([[6, 4, 8], [2, 6, 0], [2, 2, 6]]) * units('m/s')
c, vort = divergence_vorticity(u,
v,
1 * units.meters,
2 * units.meters,
dim_order='yx')
true_c = np.array([[0., 4., 0.], [1., 0.5, -0.5], [2., 0., 5.]
]) / units.sec
true_vort = np.array([[-1., 2., 7.], [3.5, -1.5, -6.], [-2., 0., 1.]
]) / units.sec
assert_array_equal(c, true_c)
assert_array_equal(vort, true_vort)
# Now try for xy ordered
c, vort = divergence_vorticity(u.T,
v.T,
1 * units.meters,
2 * units.meters,
dim_order='xy')
assert_array_equal(c, true_c.T)
assert_array_equal(vort, true_vort.T)
def test_default_order_warns():
"""Test that using the default array ordering issues a warning."""
u = np.ones((3, 3)) * units('m/s')
with pytest.warns(FutureWarning):
divergence_vorticity(u, u, 1 * units.meter, 1 * units.meter)