Source code for lenstronomy.LensModel.Profiles.hessian

__author__ = 'sibirrer'

from lenstronomy.LensModel.Profiles.base_profile import LensProfileBase

__all__ = ['Hessian']


[docs]class Hessian(LensProfileBase): """ class for constant Hessian distortion (second order) The input is in the same convention as the LensModel.hessian() output. """ param_names = ['f_xx', 'f_yy', 'f_xy', 'f_yx', 'ra_0', 'dec_0'] lower_limit_default = {'f_xx': -100, 'f_yy': -100, 'f_xy': -100, 'f_yx': -100, 'ra_0': -100, 'dec_0': -100} upper_limit_default = {'f_xx': 100, 'f_yy': 100, 'f_xy': 100, 'f_yx': 100, 'ra_0': 100, 'dec_0': 100}
[docs] def function(self, x, y, f_xx, f_yy, f_xy, f_yx, ra_0=0, dec_0=0): """ :param x: x-coordinate (angle) :param y: y0-coordinate (angle) :param f_xx: dalpha_x/dx :param f_yy: dalpha_y/dy :param f_xy: dalpha_x/dy :param f_yx: dalpha_y/dx :param ra_0: x/ra position where shear deflection is 0 :param dec_0: y/dec position where shear deflection is 0 :return: lensing potential """ x_ = x - ra_0 y_ = y - dec_0 f_ = 1/2. * (f_xx * x_ * x_ + (f_xy + f_yx) * x_ * y_ + f_yy * y_ * y_) return f_
[docs] def derivatives(self, x, y, f_xx, f_yy, f_xy, f_yx, ra_0=0, dec_0=0): """ :param x: x-coordinate (angle) :param y: y0-coordinate (angle) :param f_xx: dalpha_x/dx :param f_yy: dalpha_y/dy :param f_xy: dalpha_x/dy :param f_yx: dalpha_y/dx :param ra_0: x/ra position where shear deflection is 0 :param dec_0: y/dec position where shear deflection is 0 :return: deflection angles """ x_ = x - ra_0 y_ = y - dec_0 f_x = f_xx * x_ + f_xy * y_ f_y = f_yx * x_ + f_yy * y_ return f_x, f_y
[docs] def hessian(self, x, y, f_xx, f_yy, f_xy, f_yx, ra_0=0, dec_0=0): """ Hessian. Attention: If f_xy != f_yx then this function is not accurate! :param x: x-coordinate (angle) :param y: y0-coordinate (angle) :param f_xx: dalpha_x/dx :param f_yy: dalpha_y/dy :param f_xy: dalpha_x/dy :param f_yx: dalpha_y/dx :param ra_0: x/ra position where shear deflection is 0 :param dec_0: y/dec position where shear deflection is 0 :return: f_xx, f_yy, f_xy """ return f_xx, f_xy, f_yx, f_yy