This experiment tests a sharper version of the current solver challenge hypothesis.
The working idea was:
maybe the remaining pose-free anisotropic solver challenge is not “find a universally better alpha estimator,” but “route each trial to the right refinement policy before refinement starts.”
The candidate routing signals tested here are:
- a raw anisotropy-to-skew ratio from the top marginalized seed
- a support-aware orbit-alias index from the same top seed plus the actual observation mask
The two refinement policies are:
- fixed-family alpha-only search
- geometry-plus-alpha family-switching search
The experiment script is run_regime_router_experiment.py.
Before the benchmark, the new script was checked explicitly.
Code sanity:
- script compiled cleanly
Support-aware alias-index invariance:
- audit cases:
20 - max joint-shift delta:
1.3323e-15
That matters because the new index is supposed to measure pose-related alias pressure. If jointly rotating the seed signature and the mask changed the index materially, the index itself would be suspect.
Router logic audit:
- leave-one-out toy accuracy:
1.0 - leave-one-out toy mean routed alpha error:
0.1
That is a direct audit of the threshold-and-direction selection logic used in the benchmark.
This is a focused pilot on the current hard branch.
Scope:
- observation regimes:
sparse_full_noisysparse_partial_high_noise
- anisotropy band:
moderate
- geometry-skew bins:
low_skewmid_skewhigh_skew
Trials:
4trials per cell24trials total
For each trial:
- take the top marginalized seed
- compute two candidate router signals from that seed
- run both refinement policies:
- alpha-only fixed-family search
- geometry-plus-alpha family switching
- record which policy actually gives lower alpha error
- evaluate leave-one-out threshold routers for each signal
The raw ratio is:
- anisotropy strength
|log(alpha_seed)| - divided by top-seed skew magnitude
|t_seed|
The support-aware orbit-alias index is:
- how much alpha perturbations around the top seed can be absorbed by optimal shifts under the current mask
- divided by how visible small skew perturbations remain under the same mask
So the support-aware index tries to encode:
hidden pose pressure relative to visible geometry anchor strength
The result is informative, but it does not validate the simplest scalar-router design.
Neither scalar router beats the fixed alpha-only policy overall. The raw anisotropy-to-skew ratio carries some useful signal and tracks the sparse-full branch surprisingly well, but the current support-aware alias index does not improve routing enough to beat the simple baseline. So the routing idea has legs, but not yet in one-scalar form.
The summary file is regime_router_summary.json.
Overall means:
- alpha-only fixed-family search:
0.1648 - geometry-plus-alpha family switching:
0.1678 - raw-ratio router:
0.1692 - support-aware alias router:
0.2038 - oracle router over the two methods:
0.1193
Overall leave-one-out routing accuracy:
- raw-ratio router:
0.4167 - support-aware router:
0.3750
So the direct practical answer is clear:
in this pilot, neither scalar router is good enough yet to replace the current fixed alpha-only default.
This branch establishes a real part of the routing idea.
- alpha-only:
0.1565 - geometry-plus-alpha:
0.1101 - raw-ratio router:
0.1104 - support-aware router:
0.1861 - oracle router over the two methods:
0.0772
This is the strongest positive surprise in the experiment.
The raw ratio almost matches the better geometry-plus-alpha policy here.
So in the sparse-full branch:
the simple ratio already contains a real clue about when geometry freedom helps.
This branch behaves the other way.
- alpha-only:
0.1730 - geometry-plus-alpha:
0.2254 - raw-ratio router:
0.2281 - support-aware router:
0.2214 - oracle router over the two methods:
0.1614
Here the fixed alpha-only policy is still the best practical choice.
Both routers lose ground relative to the alpha-only baseline.
So in the sparse-partial branch:
neither scalar signal is strong enough yet to suppress harmful geometry motion reliably.
The cell summaries show why the scalar routing rule is not complete.
-
low_skew- alpha-only:
0.1073 - family switch:
0.1043 - raw router:
0.1043 - support-aware router:
0.1043
- alpha-only:
-
mid_skew- alpha-only:
0.2247 - family switch:
0.2088 - raw router:
0.2088 - support-aware router:
0.3128
- alpha-only:
-
high_skew- alpha-only:
0.1376 - family switch:
0.0172 - raw router:
0.0179 - support-aware router:
0.1411
- alpha-only:
The raw router is very close to the right answer in every sparse-full cell.
The current support-aware index is not.
-
low_skew- alpha-only:
0.2011 - family switch:
0.2474 - raw router:
0.2695 - support-aware router:
0.2474
- alpha-only:
-
mid_skew- alpha-only:
0.2022 - family switch:
0.2163 - raw router:
0.1988 - support-aware router:
0.2022
- alpha-only:
-
high_skew- alpha-only:
0.1159 - family switch:
0.2124 - raw router:
0.2159 - support-aware router:
0.2147
- alpha-only:
This is the branch where the scalar-router idea still falls short.
The raw ratio keeps over-choosing geometry freedom, and the current support-aware index does not suppress that strongly enough.
This result does not kill the routing idea.
It sharpens it.
What it establishes:
- the solver challenge is a policy-routing problem rather than a single-estimator problem
- the raw ratio carries real signal in the sparse-full branch
- the current support-aware index is not the right compressed variable
What it does not establish:
- a single scalar based only on the top seed is already enough to route all moderate sparse cells correctly
The strongest reading is:
support regime itself still matters too much to be compressed away by the current scalar router design. The sparse-full and sparse-partial branches remain qualitatively different even after adding the first support-aware alias metric.
That is the central outcome of the experiment.
The most useful clue is this:
the raw ratio nearly solves the sparse-full branch, while the sparse-partial branch resists both scalar routers.
That points to a stronger next question:
- not “find a better single scalar”
- but “can we build a two-stage router that first identifies support type or visible support geometry, then applies a scalar rule inside that branch?”
In other words:
- sparse-full is a ratio-routable branch
- sparse-partial needs an explicit support-aware gate before any scalar alias measure becomes useful
Key figures:
The scatter is the right first look. It shows how each trial’s gain from geometry freedom relates to:
- the raw anisotropy-to-skew ratio
- the support-aware orbit-alias index
The bar figure then makes the practical outcome obvious:
- the raw router almost tracks the sparse-full winner
- neither router is good enough to beat alpha-only overall