def test_shst_deformation_asym():
"""Test shearing and stretching deformation 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')
with pytest.warns(MetpyDeprecationWarning):
sh, st = shearing_stretching_deformation(u,
v,
1 * units.meters,
2 * units.meters,
dim_order='yx')
true_sh = np.array([[-7.5, -1.5, 1.], [9.5, -0.5, -11.], [1.5, 5.5, 12.]
]) / units.sec
true_st = np.array([[4., 0.5, 12.5], [4., 1.5, -0.5], [1., 5.5, -4.5]
]) / units.sec
assert_array_equal(sh, true_sh)
assert_array_equal(st, true_st)
# Now try for yx ordered
with pytest.warns(MetpyDeprecationWarning):
sh, st = shearing_stretching_deformation(u.T,
v.T,
1 * units.meters,
2 * units.meters,
dim_order='xy')
assert_array_equal(sh, true_sh.T)
assert_array_equal(st, true_st.T)
def test_shst_deformation_asym():
"""Test vorticity and convergence 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')
sh, st = shearing_stretching_deformation(u, v, 1 * units.meters, 2 * units.meters,
dim_order='yx')
true_sh = np.array([[-3., 0., 1.], [4.5, -0.5, -6.], [2., 4., 7.]]) / units.sec
true_st = np.array([[4., 2., 8.], [3., 1.5, 0.5], [2., 4., -1.]]) / units.sec
assert_array_equal(sh, true_sh)
assert_array_equal(st, true_st)
# Now try for yx ordered
sh, st = shearing_stretching_deformation(u.T, v.T, 1 * units.meters, 2 * units.meters,
dim_order='xy')
assert_array_equal(sh, true_sh.T)
assert_array_equal(st, true_st.T)
def test_shst_zero_gradient():
"""Test shear_stretching_deformation when there is zero gradient."""
u = np.ones((3, 3)) * units('m/s')
sh, st = shearing_stretching_deformation(u, u, 1 * units.meter, 1 * units.meter,
dim_order='xy')
truth = np.zeros_like(u) / units.sec
assert_array_equal(sh, truth)
assert_array_equal(st, truth)
def test_shst_deformation():
"""Test of shearing and stretching deformation calculation for basic case."""
a = np.arange(3)
u = np.c_[a, a, a] * units('m/s')
sh, st = shearing_stretching_deformation(u, u, 1 * units.meter, 1 * units.meter,
dim_order='xy')
true_sh = np.ones_like(u) / units.sec
true_st = np.ones_like(u) / units.sec
assert_array_equal(sh, true_st)
assert_array_equal(st, true_sh)
def test_shst_zero_stretching():
"""Test shear_stretching_deformation when there is only shearing."""
a = np.arange(3)
u = np.c_[a, a, a] * units('m/s')
sh, st = shearing_stretching_deformation(u, u.T, 1 * units.meter, 1 * units.meter,
dim_order='yx')
true_sh = 2. * np.ones_like(u) / units.sec
true_st = np.zeros_like(u) / units.sec
assert_array_equal(sh, true_sh)
assert_array_equal(st, true_st)
def windProducts(x, y, u, v):
dx, dy = mpcalc.lat_lon_grid_spacing(x, y)
deformation = numpy.zeros(u.shape)
convergence = numpy.zeros(u.shape)
for i in range(u.shape[0]):
shear, stretch = mpcalc.shearing_stretching_deformation(
u[i, :, :], v[i, :, :], dx, dy)
deformation[i] = numpy.sqrt(shear**2 + stretch**2)
convergence[i] = -mpcalc.divergence(u[i, :, :], v[i, :, :], dx, dy)
return deformation, convergence
