import numpy as np
from lenstronomy.Util import util
from lenstronomy.LightModel.light_model import LightModel
__all__ = ["light2mass_interpol"]
[docs]
def light2mass_interpol(
lens_light_model_list,
kwargs_lens_light,
numPix=100,
deltaPix=0.05,
subgrid_res=5,
center_x=0,
center_y=0,
):
"""Takes a lens light model and turns it numerically in a lens model (with all
lensmodel quantities computed on a grid). Then provides an interpolated grid for the
quantities.
:param kwargs_lens_light: lens light keyword argument list
:param numPix: number of pixels per axis for the return interpolation
:param deltaPix: interpolation/pixel size
:param center_x: center of the grid
:param center_y: center of the grid
:param subgrid_res: subgrid for the numerical integrals
:return: keyword arguments for 'INTERPOL' lens model
"""
# make super-sampled grid
x_grid_sub, y_grid_sub = util.make_grid(
numPix=numPix * 5, deltapix=deltaPix, subgrid_res=subgrid_res
)
import lenstronomy.Util.mask_util as mask_util
mask = mask_util.mask_azimuthal(x_grid_sub, y_grid_sub, center_x, center_y, r=1)
x_grid, y_grid = util.make_grid(numPix=numPix, deltapix=deltaPix)
# compute light on the subgrid
lightModel = LightModel(light_model_list=lens_light_model_list)
flux = lightModel.surface_brightness(x_grid_sub, y_grid_sub, kwargs_lens_light)
flux_norm = np.sum(flux[mask == 1]) / np.sum(mask)
flux /= flux_norm
from lenstronomy.LensModel import convergence_integrals as integral
# compute lensing quantities with subgrid
convergence_sub = util.array2image(flux)
f_x_sub, f_y_sub = integral.deflection_from_kappa_grid(
convergence_sub, grid_spacing=deltaPix / float(subgrid_res)
)
f_sub = integral.potential_from_kappa_grid(
convergence_sub, grid_spacing=deltaPix / float(subgrid_res)
)
# interpolation function on lensing quantities
x_axes_sub, y_axes_sub = util.get_axes(x_grid_sub, y_grid_sub)
from lenstronomy.LensModel.Profiles.interpol import Interpol
interp_func = Interpol()
interp_func.do_interp(x_axes_sub, y_axes_sub, f_sub, f_x_sub, f_y_sub)
# compute lensing quantities on sparser grid
x_axes, y_axes = util.get_axes(x_grid, y_grid)
f_ = interp_func.function(x_grid, y_grid)
f_x, f_y = interp_func.derivatives(x_grid, y_grid)
# numerical differentials for second order differentials
from lenstronomy.LensModel.lens_model import LensModel
lens_model = LensModel(lens_model_list=["INTERPOL"])
kwargs = [
{
"grid_interp_x": x_axes_sub,
"grid_interp_y": y_axes_sub,
"f_": f_sub,
"f_x": f_x_sub,
"f_y": f_y_sub,
}
]
f_xx, f_xy, f_yx, f_yy = lens_model.hessian(x_grid, y_grid, kwargs, diff=0.00001)
kwargs_interpol = {
"grid_interp_x": x_axes,
"grid_interp_y": y_axes,
"f_": util.array2image(f_),
"f_x": util.array2image(f_x),
"f_y": util.array2image(f_y),
"f_xx": util.array2image(f_xx),
"f_xy": util.array2image(f_xy),
"f_yy": util.array2image(f_yy),
}
return kwargs_interpol