docs: add module docstrings and fill missing method docstrings in operate package

- Add module-level docstring to image.py explaining the OperateImage /
  OperateImageList / OperateImageGalaxies mixin hierarchy
- Add module-level docstring to lens_calc.py listing all the lensing
  quantities that LensCalc can derive from a deflection callable
- Add docstrings to OperateImage.image_2d_from and OperateImage.has
  (previously only raised NotImplementedError without documentation)
- Add docstring to _blurred_image_2d_from explaining its role as the
  internal PSF convolution helper

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: 2 people

autogalaxy/operate/image.py

@@ -1,3 +1,19 @@
+"""
+Mixin classes that add image-operation methods (PSF convolution, Fourier transform) to light objects.
+
+The three mixin classes here are arranged in a hierarchy:
+
+- `OperateImage` — methods that operate on a **single** image from a light object
+  (e.g. a `LightProfile` or `Galaxy`).
+- `OperateImageList` — extends `OperateImage` with methods that operate on a **list** of images,
+  one per light profile component.
+- `OperateImageGalaxies` — extends `OperateImageList` with methods that operate on a **dict** mapping
+  each `Galaxy` to its image, preserving galaxy identity through the pipeline.
+
+All three classes are mixins — they are not instantiated directly but are inherited by light objects
+(`LightProfile`, `Galaxy`, `Galaxies`, `Tracer`) to expose a consistent API for blurring and Fourier
+transforming images.
+"""
 from __future__ import annotations
 import numpy as np
 from typing import TYPE_CHECKING, Dict, List, Optional
@@ -24,9 +40,31 @@ class OperateImage:
     def image_2d_from(
         self, grid: aa.Grid2D, xp=np, operated_only: Optional[bool] = None
     ) -> aa.Array2D:
+        """
+        Abstract method — return the 2D image of this light object at every coordinate on `grid`.
+
+        Subclasses (e.g. `LightProfile`, `Galaxy`) implement this method to evaluate their surface
+        brightness at each (y, x) coordinate.
+
+        Parameters
+        ----------
+        grid
+            The 2D (y, x) coordinates where the image is evaluated.
+        operated_only
+            Controls which light profiles contribute. `None` (default) returns all profiles;
+            `True` returns only `LightProfileOperated` images; `False` excludes them.
+        """
         raise NotImplementedError
 
     def has(self, cls) -> bool:
+        """
+        Returns `True` if any attribute of this object is an instance of `cls`, else `False`.
+
+        Parameters
+        ----------
+        cls
+            The class type to search for.
+        """
         raise NotImplementedError
 
     def _blurred_image_2d_from(
@@ -36,6 +74,21 @@ def _blurred_image_2d_from(
         psf: aa.Convolver,
         xp=np,
     ) -> aa.Array2D:
+        """
+        Convolve a 2D image with a PSF using the supplied `Convolver`.
+
+        This is the internal helper used by `blurred_image_2d_from`. It does not handle the
+        `LightProfileOperated` logic — the caller must do that separately.
+
+        Parameters
+        ----------
+        image_2d
+            The 2D image of the masked pixels to be convolved.
+        blurring_image_2d
+            The 2D image of the pixels just outside the mask whose light blurs into the masked region.
+        psf
+            The PSF convolver that performs the 2D convolution.
+        """
 
         values = psf.convolved_image_from(
             image=image_2d, blurring_image=blurring_image_2d, xp=xp

autogalaxy/operate/lens_calc.py

@@ -1,3 +1,21 @@
+"""
+`LensCalc` — a calculator that derives all secondary lensing quantities from a deflection callable.
+
+Given any object that exposes `deflections_yx_2d_from` (a `MassProfile`, `Galaxy`, `Galaxies`, or
+`Tracer`), `LensCalc` computes:
+
+- **Hessian** (four components: H_yy, H_xy, H_yx, H_xx) — the matrix of second derivatives of the
+  lensing potential, computed by finite differences (NumPy) or automatic differentiation (JAX).
+- **Convergence via Hessian** — κ = 0.5 (H_yy + H_xx), independent of the analytic profile formula.
+- **Shear** — γ₁ = 0.5 (H_xx − H_yy), γ₂ = H_xy.
+- **Magnification** — μ = 1 / det(I − H).
+- **Critical curves** — image-plane loci where det(I − H) = 0, found via marching squares.
+- **Caustics** — source-plane images of the critical curves.
+- **Einstein radius** — the effective radius from the area enclosed by the tangential critical curve.
+- **Fermat potential** — φ(θ) = ½|θ − β|² − ψ(θ), using the optional potential callable.
+
+The class is constructed with `LensCalc.from_mass_obj(mass)` or `LensCalc.from_tracer(tracer)`.
+"""
 from functools import wraps
 import logging
 import numpy as np