feat!: point-source position fit defaults to FitPositionsImagePairAllSolved

AnalysisPoint (was FitPositionsImagePairRepeat) and FitPointDataset (was
FitPositionsImagePair) now default to all-to-all pairing with the
analytically-solved source centre, per the #678 phase B truth-anchored A100
evidence: repeat pairing catastrophically mis-ranks truth when an observed
image is missing (delta +1.8e5 logL on the simple_missing discriminator)
while the all-to-all Occam mixture absorbs it; solved centres converge
under gradient searches where free centres plateau; solved posteriors are
not overconfident (einstein_radius sigma 0.038 vs 0.027 free).

Centre-bearing profiles (ps.Point / ps.PointFlux) used with the new default
raise PointProfileMismatchException loudly, directing users to pair
ps.PointSolved with the default or pass a free-centre fit class explicitly.
Tests pinning free-centre literals now pass their fit class explicitly; new
tests pin the default and the loud mismatch.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DnTmLoJjJgMTze5uAbg1Jd

Author: 2 people

autolens/fixtures.py

@@ -112,6 +112,9 @@ def make_fit_point_dataset_x2_plane():
         dataset=make_point_dataset(),
         tracer=make_tracer_x2_plane_point(),
         solver=make_solver(),
+        # The tracer's point source is centre-bearing (`ps.Point`), which the
+        # solved-centre default fit class rejects — use the free-centre pair fit.
+        fit_positions_cls=al.FitPositionsImagePair,
     )
 
 

autolens/point/fit/dataset.py

@@ -5,7 +5,7 @@
 (image-plane positions, fluxes, and/or time delays) simultaneously.  It creates and
 stores individual fit objects for each component that is present in the dataset:
 
-- ``FitPositionsImagePair`` (or another positions fit class) — fits image-plane positions.
+- ``FitPositionsImagePairAllSolved`` (or another positions fit class) — fits image-plane positions.
 - ``FitFluxes`` — fits flux ratios (if fluxes are in the dataset).
 - ``FitTimeDelays`` — fits time delays (if time delays are in the dataset).
 
@@ -21,7 +21,7 @@ class is used by ``AnalysisPoint`` as the evaluation engine inside the
 from autolens.point.fit.times_delays import FitTimeDelays
 from autolens.lens.tracer import Tracer
 
-from autolens.point.fit.positions.image.pair import FitPositionsImagePair
+from autolens.point.fit.positions.image.pair_all import FitPositionsImagePairAllSolved
 from autolens import exc
 
 
@@ -31,7 +31,7 @@ def __init__(
         dataset: PointDataset,
         tracer: Tracer,
         solver: PointSolver,
-        fit_positions_cls=FitPositionsImagePair,
+        fit_positions_cls=FitPositionsImagePairAllSolved,
         xp=np,
         fit_flux_cls=FitFluxes,
         fit_time_delays_cls=FitTimeDelays,

autolens/point/model/analysis.py

@@ -23,7 +23,7 @@
 
 from autolens.analysis.analysis.lens import AnalysisLens
 from autolens.analysis.exceptions import raise_fit_exception
-from autolens.point.fit.positions.image.pair_repeat import FitPositionsImagePairRepeat
+from autolens.point.fit.positions.image.pair_all import FitPositionsImagePairAllSolved
 from autolens.point.fit.dataset import FitPointDataset
 from autolens.point.fit.fluxes import FitFluxes
 from autolens.point.fit.times_delays import FitTimeDelays
@@ -41,7 +41,7 @@ def __init__(
         self,
         dataset: PointDataset,
         solver: PointSolver,
-        fit_positions_cls=FitPositionsImagePairRepeat,
+        fit_positions_cls=FitPositionsImagePairAllSolved,
         image=None,
         cosmology: ag.cosmo.LensingCosmology = None,
         title_prefix: str = None,

test_autolens/point/fit/test_fit_dataset.py

@@ -33,7 +33,10 @@ def test__fit_dataset__matching_point_name__positions_log_likelihood_correct(
     )
 
     fit = al.FitPointDataset(
-        dataset=dataset, tracer=point_source_tracer, solver=mock_solver
+        dataset=dataset,
+        tracer=point_source_tracer,
+        solver=mock_solver,
+        fit_positions_cls=al.FitPositionsImagePair,
     )
 
     assert fit.positions.log_likelihood == pytest.approx(-22.14472, 1.0e-4)
@@ -111,13 +114,64 @@ def test__fit_dataset__positions_and_flux__both_log_likelihoods_correct_and_sum(
         fluxes_noise_map=flux_noise_map,
     )
 
-    fit = al.FitPointDataset(dataset=dataset, tracer=tracer, solver=solver)
+    fit = al.FitPointDataset(
+        dataset=dataset,
+        tracer=tracer,
+        solver=solver,
+        fit_positions_cls=al.FitPositionsImagePair,
+    )
 
     assert fit.positions.log_likelihood == pytest.approx(-22.14472, 1.0e-4)
     assert fit.flux.log_likelihood == pytest.approx(-2.9920449, 1.0e-4)
     assert fit.log_likelihood == fit.positions.log_likelihood + fit.flux.log_likelihood
 
 
+def test__fit_dataset__default_positions_fit_is_all_to_all_solved(
+    positions_and_noise, mock_solver
+):
+    """
+    The #678 phase B evidence campaign moved the demonstrated defaults to
+    solved centres with all-to-all pairing: the missing-image discriminator
+    showed repeat pairing catastrophically mis-ranks truth when an observed
+    image is absent, while the all-to-all Occam mixture absorbs it.
+    """
+    positions, noise_map = positions_and_noise
+    dataset = al.PointDataset(
+        name="point_0", positions=positions, positions_noise_map=noise_map
+    )
+
+    solved_tracer = al.Tracer(
+        galaxies=[
+            al.Galaxy(redshift=0.5, mass=al.mp.IsothermalSph(einstein_radius=1.0)),
+            al.Galaxy(redshift=1.0, point_0=al.ps.PointSolved()),
+        ]
+    )
+
+    fit = al.FitPointDataset(dataset=dataset, tracer=solved_tracer, solver=mock_solver)
+
+    assert fit.fit_positions_cls is al.FitPositionsImagePairAllSolved
+    assert isinstance(fit.positions, al.FitPositionsImagePairAllSolved)
+    assert np.isfinite(fit.log_likelihood)
+
+
+def test__fit_dataset__default_with_centre_bearing_profile_raises_loudly(
+    point_source_tracer, positions_and_noise, mock_solver
+):
+    # A `ps.Point` centre would be silently ignored by a solved-centre fit, so
+    # the mismatch must raise, pointing the user at the free-centre class.
+    positions, noise_map = positions_and_noise
+    dataset = al.PointDataset(
+        name="point_0", positions=positions, positions_noise_map=noise_map
+    )
+
+    fit = al.FitPointDataset(
+        dataset=dataset, tracer=point_source_tracer, solver=mock_solver
+    )
+
+    with pytest.raises(al.exc.PointProfileMismatchException):
+        fit.positions.log_likelihood
+
+
 def test__fit_dataset__fit_flux_cls_and_fit_time_delays_cls_hooks_are_forwarded_and_default_unchanged(
     point_source_tracer, positions_and_noise, mock_solver
 ):

test_autolens/point/model/test_analysis_point.py

@@ -69,6 +69,15 @@ def _test__make_result__result_imaging_is_returned(point_dataset):
     assert isinstance(result, ResultPoint)
 
 
+def test__default_fit_positions_cls_is_all_to_all_solved(point_dataset):
+    # #678 phase B defaults decision: solved centres + all-to-all pairing.
+    solver = al.m.MockPointSolver(model_positions=point_dataset.positions)
+
+    analysis = al.AnalysisPoint(dataset=point_dataset, solver=solver, use_jax=False)
+
+    assert analysis.fit_positions_cls is al.FitPositionsImagePairAllSolved
+
+
 def test__figure_of_merit__matches_correct_fit_given_galaxy_profiles(
     positions_x2, positions_x2_noise_map
 ):
@@ -86,7 +95,12 @@ def test__figure_of_merit__matches_correct_fit_given_galaxy_profiles(
 
     solver = al.m.MockPointSolver(model_positions=positions_x2)
 
-    analysis = al.AnalysisPoint(dataset=point_dataset, solver=solver, use_jax=False)
+    analysis = al.AnalysisPoint(
+        dataset=point_dataset,
+        solver=solver,
+        fit_positions_cls=al.FitPositionsImagePairRepeat,
+        use_jax=False,
+    )
 
     instance = model.instance_from_unit_vector([])
     analysis_log_likelihood = analysis.log_likelihood_function(instance=instance)
@@ -107,7 +121,12 @@ def test__figure_of_merit__matches_correct_fit_given_galaxy_profiles(
     model_positions = al.Grid2DIrregular([(0.0, 1.0), (1.0, 2.0)])
     solver = al.m.MockPointSolver(model_positions=model_positions)
 
-    analysis = al.AnalysisPoint(dataset=point_dataset, solver=solver, use_jax=False)
+    analysis = al.AnalysisPoint(
+        dataset=point_dataset,
+        solver=solver,
+        fit_positions_cls=al.FitPositionsImagePairRepeat,
+        use_jax=False,
+    )
 
     analysis_log_likelihood = analysis.log_likelihood_function(instance=instance)
 
@@ -147,7 +166,12 @@ def test__figure_of_merit__includes_fit_fluxes(
 
     solver = al.m.MockPointSolver(model_positions=positions_x2)
 
-    analysis = al.AnalysisPoint(dataset=point_dataset, solver=solver, use_jax=False)
+    analysis = al.AnalysisPoint(
+        dataset=point_dataset,
+        solver=solver,
+        fit_positions_cls=al.FitPositionsImagePairRepeat,
+        use_jax=False,
+    )
 
     instance = model.instance_from_unit_vector([])
 
@@ -179,7 +203,12 @@ def test__figure_of_merit__includes_fit_fluxes(
     model_positions = al.Grid2DIrregular([(0.0, 1.0), (1.0, 2.0)])
     solver = al.m.MockPointSolver(model_positions=model_positions)
 
-    analysis = al.AnalysisPoint(dataset=point_dataset, solver=solver, use_jax=False)
+    analysis = al.AnalysisPoint(
+        dataset=point_dataset,
+        solver=solver,
+        fit_positions_cls=al.FitPositionsImagePairRepeat,
+        use_jax=False,
+    )
 
     instance = model.instance_from_unit_vector([])
     analysis_log_likelihood = analysis.log_likelihood_function(instance=instance)