def __init__(
self,
positions: aa.Grid2DIrregular,
noise_map: aa.ValuesIrregular,
tracer: Tracer,
):
"""
Given a positions dataset, which is a list of positions with names that associated them to model source
galaxies, use a `Tracer` to determine the traced coordinate positions in the source-plane.
Different children of this abstract class are available which use the traced coordinates to define a chi-squared
value in different ways.
Parameters
-----------
positions : Grid2DIrregular
The (y,x) arc-second coordinates of named positions which the log_likelihood is computed using. Positions
are paired to galaxies in the `Tracer` using their names.
tracer : Tracer
The object that defines the ray-tracing of the strong lens system of galaxies.
noise_value
The noise-value assumed when computing the log likelihood.
"""
self.positions = positions
self.noise_map = noise_map
self.source_plane_positions = tracer.traced_grid_2d_list_from(
grid=positions)[-1]
def via_tracer_from(self, tracer: Tracer, grid: aa.type.Grid2DLike,
plane_index: int) -> aplt.Visuals2D:
"""
From a `Tracer` get the attributes that can be plotted and returns them in a `Visuals2D` object.
Only attributes with `True` entries in the `Include` object are extracted.
From a tracer the following attributes can be extracted for plotting:
- origin: the (y,x) origin of the coordinate system used to plot the light object's quantities in 2D.
- border: the border of the mask of the grid used to plot the light object's quantities in 2D.
- light profile centres: the (y,x) centre of every `LightProfile` in the object.
- mass profile centres: the (y,x) centre of every `MassProfile` in the object.
- critical curves: the critical curves of all of the tracer's mass profiles combined.
- caustics: the caustics of all of the tracer's mass profiles combined.
When plotting a `Tracer` it is common for plots to only display quantities corresponding to one plane at a time
(e.g. the convergence in the image plane, the source in the source plane). Therefore, quantities are only
extracted from one plane, specified by the input `plane_index`.
Parameters
----------
tracer
The `Tracer` object which has attributes extracted for plotting.
grid
The 2D grid of (y,x) coordinates used to plot the tracer's quantities in 2D.
plane_index
The index of the plane in the tracer which is used to extract quantities, as only one plane is plotted
at a time.
Returns
-------
vis.Visuals2D
A collection of attributes that can be plotted by a `Plotter` object.
"""
origin = self.get("origin",
value=aa.Grid2DIrregular(grid=[grid.origin]))
border = self.get("border", value=grid.mask.border_grid_sub_1.binned)
if border is not None and len(border) > 0 and plane_index > 0:
border = tracer.traced_grid_2d_list_from(grid=border)[plane_index]
light_profile_centres = self.get(
"light_profile_centres",
tracer.planes[plane_index].extract_attribute(
cls=ag.lp.LightProfile, attr_name="centre"),
)
mass_profile_centres = self.get(
"mass_profile_centres",
tracer.planes[plane_index].extract_attribute(cls=ag.mp.MassProfile,
attr_name="centre"),
)
if plane_index == 0:
critical_curves = self.get(
"critical_curves",
tracer.critical_curves_from(grid=grid),
"critical_curves",
)
else:
critical_curves = None
if plane_index == 1:
caustics = self.get("caustics", tracer.caustics_from(grid=grid),
"caustics")
else:
caustics = None
return self.visuals + self.visuals.__class__(
origin=origin,
border=border,
light_profile_centres=light_profile_centres,
mass_profile_centres=mass_profile_centres,
critical_curves=critical_curves,
caustics=caustics,
)