Short-circuit set_snr_of_snr_light_profiles when no SNR profiles present (#471)

Previously the method always ray-traced the full grid before looking for
LightProfileSNR instances, which is wasted work for simulators that use
only regular light profiles (e.g. the cluster simulator, which uses
SersicSph and SersicCore and ray-traced a 1000x1000 grid through 5 dPIE
profiles + an NFW halo for nothing).

Scan the tracer's light profiles up-front; if none are LightProfileSNR,
return before any ray-tracing.

Co-authored-by: Jammy2211 <JNightingale2211@gmail.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: 3 people

autolens/lens/tracer.py

@@ -1206,6 +1206,15 @@ def set_snr_of_snr_light_profiles(
             The psf of the simulated imaging which can change the S/N of the light profile due to spreading out
             the emission.
         """
+        has_snr_profile = any(
+            isinstance(light_profile, LightProfileSNR)
+            for galaxies in self.planes
+            for galaxy in galaxies
+            for light_profile in galaxy.cls_list_from(cls=ag.LightProfile)
+        )
+        if not has_snr_profile:
+            return
+
         grid = aa.Grid2D.uniform(
             shape_native=grid.shape_native,
             pixel_scales=grid.pixel_scales,