Source code for lenstronomy.LensModel.Profiles.dipole
__author__ = 'sibirrer'
import numpy as np
from lenstronomy.LensModel.Profiles.base_profile import LensProfileBase
__all__ = ['Dipole', 'DipoleUtil']
[docs]class Dipole(LensProfileBase):
"""
class for dipole response of two massive bodies (experimental)
"""
param_names = ['com_x', 'com_y', 'phi_dipole', 'coupling']
lower_limit_default = {'com_x': -100, 'com_y': -100, 'phi_dipole': -10, 'coupling': -10}
upper_limit_default = {'com_x': 100, 'com_y': 100, 'phi_dipole': 10, 'coupling': 10}
[docs] def function(self, x, y, com_x, com_y, phi_dipole, coupling):
# coordinate shift
x_shift = x - com_x
y_shift = y - com_y
# rotation angle
sin_phi = np.sin(phi_dipole)
cos_phi = np.cos(phi_dipole)
x_ = cos_phi*x_shift + sin_phi*y_shift
y_ = -sin_phi*x_shift + cos_phi*y_shift
r = np.sqrt(x_**2 + y_**2)
# f_ = coupling**2 * (x_/y_)**2 # np.sqrt(np.abs(y_)/r) * np.abs(y_)
# f_ = coupling * np.abs(x_)
f_ = np.zeros_like(x_)
return f_
[docs] def derivatives(self, x, y, com_x, com_y, phi_dipole, coupling):
# coordinate shift
x_shift = x - com_x
y_shift = y - com_y
# rotation angle
sin_phi = np.sin(phi_dipole)
cos_phi = np.cos(phi_dipole)
x_ = cos_phi*x_shift + sin_phi*y_shift
y_ = -sin_phi*x_shift + cos_phi*y_shift
f_x_prim = coupling * x_/np.sqrt(x_**2 + y_**2)
f_y_prim = np.zeros_like(x_)
# rotate back
f_x = cos_phi*f_x_prim-sin_phi*f_y_prim
f_y = sin_phi*f_x_prim+cos_phi*f_y_prim
return f_x, f_y
[docs] def hessian(self, x, y, com_x, com_y, phi_dipole, coupling):
# coordinate shift
x_shift = x - com_x
y_shift = y - com_y
# rotation angle
sin_phi = np.sin(phi_dipole)
cos_phi = np.cos(phi_dipole)
x_ = cos_phi*x_shift + sin_phi*y_shift
y_ = -sin_phi*x_shift + cos_phi*y_shift
r = np.sqrt(x_**2 + y_**2)
f_xx_prim = coupling*y_**2/r**3
f_xy_prim = -coupling * x_ * y_ / r**3
f_yy_prim = np.zeros_like(x_)
kappa = 1./2 * (f_xx_prim + f_yy_prim)
gamma1_value = 1./2 * (f_xx_prim - f_yy_prim)
gamma2_value = f_xy_prim
# rotate back
gamma1 = np.cos(2*phi_dipole)*gamma1_value-np.sin(2*phi_dipole)*gamma2_value
gamma2 = +np.sin(2*phi_dipole)*gamma1_value+np.cos(2*phi_dipole)*gamma2_value
f_xx = kappa + gamma1
f_yy = kappa - gamma1
f_xy = gamma2
return f_xx, f_xy, f_xy, f_yy
[docs]class DipoleUtil(object):
"""
pre-calculation of dipole properties
"""
[docs] def com(self, center1_x, center1_y, center2_x, center2_y, Fm):
"""
:return: center of mass
"""
com_x = (Fm * center1_x + center2_x)/(Fm + 1.)
com_y = (Fm * center1_y + center2_y)/(Fm + 1.)
return com_x, com_y
[docs] def mass_ratio(self, theta_E, theta_E_sub):
"""
computes mass ration of the two clumps with given Einstein radius and power law slope (clump1/sub-clump)
:param theta_E:
:param theta_E_sub:
:return:
"""
return (theta_E / theta_E_sub) ** 2
[docs] def angle(self, center1_x, center1_y, center2_x, center2_y):
"""
compute the rotation angle of the dipole
:return:
"""
phi_G = np.arctan2(center2_y - center1_y, center2_x - center1_x)
return phi_G