def _specific_angular_momentum_z(field, data):
xv, yv, zv = obtain_relative_velocity_vector(data)
rv = obtain_position_vector(data)
units = rv.units
rv = np.rollaxis(rv, 0, len(rv.shape))
rv = data.ds.arr(rv, units=units)
return rv[..., 0] * yv - rv[..., 1] * xv
def _specific_angular_momentum_y(field, data):
xv, yv, zv = obtain_relative_velocity_vector(data)
rv = obtain_position_vector(data)
units = rv.units
rv = np.rollaxis(rv, 0, len(rv.shape))
rv = data.ds.arr(rv, input_units=units)
return -(xv * rv[..., 2] - zv * rv[..., 0])
def _relative_particle_velocity(field, data):
"""The vector particle velocities in an arbitrary coordinate system
Relative to the coordinate system defined by the *bulk_velocity*
vector field parameter.
Note that the orientation of the x and y axes are arbitrary.
"""
field_names = [(ptype, f"particle_velocity_{ax}") for ax in "xyz"]
return obtain_relative_velocity_vector(data, field_names=field_names).T
def _cylindrical_z_component(field, data):
"""The cylindrical z component of the vector field
Relative to the coordinate system defined by the *normal* vector,
*center*, and *bulk_* field parameters.
"""
normal = data.get_field_parameter("normal")
vectors = obtain_relative_velocity_vector(data, (xn, yn, zn),
f"bulk_{basename}")
return get_cyl_z_component(vectors, normal)
def _spherical_phi_component(field, data):
"""The spherical phi component of the vector field
Relative to the coordinate system defined by the *normal* vector,
*center*, and *bulk_* field parameters.
"""
normal = data.get_field_parameter("normal")
vectors = obtain_relative_velocity_vector(data, (xn, yn, zn),
f"bulk_{basename}")
phi = data["index", "spherical_phi"]
return get_sph_phi_component(vectors, phi, normal)
def _cylindrical_radius_component(field, data):
"""The cylindrical radius component of the vector field
Relative to the coordinate system defined by the *normal* vector,
*center*, and *bulk_* field parameters.
"""
normal = data.get_field_parameter("normal")
vectors = obtain_relative_velocity_vector(data, (xn, yn, zn),
"bulk_%s" % basename)
theta = data["index", 'cylindrical_theta']
return get_cyl_r_component(vectors, theta, normal)
def _cylindrical_theta_component(field, data):
"""The cylindrical theta component of the vector field
Relative to the coordinate system defined by the *normal* vector,
*center*, and *bulk_* field parameters.
"""
normal = data.get_field_parameter("normal")
vectors = obtain_relative_velocity_vector(data, (xn, yn, zn),
f"bulk_{basename}")
theta = data["index", "cylindrical_theta"].copy()
theta = np.tile(theta, (3, ) + (1, ) * len(theta.shape))
return get_cyl_theta_component(vectors, theta, normal)
def test_obtain_relative_velocity_vector():
ds = fake_random_ds(64,
nprocs=8,
fields=_fields,
negative=[False, True, True, True])
dd = ds.all_data()
vels = obtain_relative_velocity_vector(dd)
assert_array_equal(vels[0, :], dd["velocity_x"])
assert_array_equal(vels[1, :], dd["velocity_y"])
assert_array_equal(vels[2, :], dd["velocity_z"])
def _spherical_radius_component(field, data):
"""The spherical radius component of the vector field
Relative to the coordinate system defined by the *normal* vector,
*center*, and *bulk_* field parameters.
"""
normal = data.get_field_parameter("normal")
vectors = obtain_relative_velocity_vector(data, (xn, yn, zn),
f"bulk_{basename}")
theta = data["index", "spherical_theta"]
phi = data["index", "spherical_phi"]
rv = get_sph_r_component(vectors, theta, phi, normal)
# Now, anywhere that radius is in fact zero, we want to zero out our
# return values.
rv[np.isnan(theta)] = 0.0
return rv
def _kinetic_energy_density(field, data):
v = obtain_relative_velocity_vector(data)
return 0.5 * data[ftype, "density"] * (v**2).sum(axis=0)
def _specific_angular_momentum_z(field, data):
xv, yv, zv = obtain_relative_velocity_vector(data)
rv = obtain_position_vector(data)
rv = np.rollaxis(rv, 0, len(rv.shape))
rv = data.ds.arr(rv, input_units=data["index", "x"].units)
return xv * rv[..., 1] - yv * rv[..., 0]
