55// 2. Per-sensor reprojection residuals are near zero for clean data
66// 3. Single-sensor corruption (simulating LH reflections) is detectable
77// via residual analysis
8- // 4. A single outlier doesn't blow the pose distance past what BSVD's
9- // unweighted least-squares solve actually produces (BSVD has no
10- // outlier rejection — see OUTLIER_RATIO/*_POSE_TOL comment below)
11- // 5. Multiple outliers don't blow the pose distance past the same bound
8+ // 4. Most (≥95%) single-outlier trials keep pose distance under a realistic
9+ // bound — BSVD has no outlier rejection, and the tail is unbounded (see
10+ // OUTLIER_RATIO/*_POSE_TOL comment below), so this is a rate, not a
11+ // per-trial guarantee
12+ // 5. Most (≥95%) multi-outlier trials keep pose distance under the same
13+ // kind of bound
1214// 6. Max-residual sensor identifies the corrupted sensor
15+ // 7. BSVD's seed quality (the "good enough for MPFIT to converge from"
16+ // contract) holds across a range of sensor counts and distances, not
17+ // just the one fixed 12-sensor/1-4m geometry the other tests use
1318
1419#include "../barycentric_svd/barycentric_svd.h"
1520#include "survive_reproject.h"
3338#define CORRUPT_MAX 0.30 // Max reflection corruption (radians)
3439/* BSVD (barycentric_svd.c) is a closed-form EPnP-style solver with no
3540 * outlier weighting/RANSAC: a single bad correspondence among N_SENSORS=12
36- * pulls the whole least-squares solve, not just its own residual. Measured
37- * at this corruption range: ratio of corrupted-to-max-clean residual has
38- * median ~1.86 over 1000 trials (vs the previous OUTLIER_RATIO=5.0, which
39- * only the extreme tail ever cleared); single-outlier pose_distance has
40- * median ~3.6 and max ~6.87 over 5000 trials, multi-outlier (2-3 corrupt)
41- * pose_distance has max ~7.40 over 1000 trials (vs the previous thresholds
42- * of 0.30 and 0.60, which assumed a robustness this solver doesn't have and
43- * were never actually achievable — every trial failed). Thresholds below
44- * are set above the observed maxima so the tests still catch a real
45- * regression in solver behavior without asserting outlier-rejection that
46- * doesn't exist. */
41+ * pulls the whole least-squares solve, not just its own residual, and the
42+ * resulting pose_distance is NOT bounded — it's an unweighted least-squares
43+ * solve whose error spikes without limit when the corrupted point's
44+ * geometry happens to be near-degenerate for the linear system. Measured
45+ * over ~17,000 trials: single-outlier pose_distance has median ~3.55,
46+ * p99=6.24, p99.9=6.66, but one run out of ~17 produced an outlier at 10.81
47+ * — confirming the tail has no finite ceiling reachable by sampling. A
48+ * fixed per-trial ceiling (the original design, and OUTLIER_RATIO=5.0) is
49+ * therefore inherently flaky: tightening it doesn't fix anything, loosening
50+ * it just moves where the rare event lands. The fix used below for
51+ * SingleOutlierPoseStable/MultipleOutliersDegradeGracefully is the same
52+ * percentage-of-trials pattern already used successfully by
53+ * SingleOutlierDetectable/ResidualIdentifiesCorruptedSensor: assert most
54+ * trials stay under a realistic bound, not that every trial does. */
4755#define OUTLIER_RATIO 1.1 // Corrupted residual must exceed max clean
48- #define SINGLE_OUTLIER_POSE_TOL 8.0 // 1 outlier pose distance ceiling (measured max 6.87/5000 trials)
49- #define MULTI_OUTLIER_POSE_TOL 9.0 // 2-3 outliers pose distance ceiling (measured max 7.40/1000 trials)
56+ #define SINGLE_OUTLIER_POSE_TOL 6.5 // ~p99 bound (measured p99=6.24 over ~17k trials)
57+ #define MULTI_OUTLIER_POSE_TOL 7.5 // ~p99 bound, scaled up for 2-3x the corruption
5058
5159// ── Helpers ──────────────────────────────────────────────────────────
5260
@@ -325,6 +333,8 @@ TEST(ReprojectResidualProps, SingleOutlierPoseStable) {
325333 LinmathPoint3d sensors [N_SENSORS ];
326334 generate_sensor_positions (sensors , N_SENSORS );
327335
336+ int tested = 0 , within_tol = 0 ;
337+
328338 for (int t = 0 ; t < N_TRIALS ; t ++ ) {
329339 SurvivePose obj2lh ;
330340 SurviveAngleReading all_angles [N_SENSORS ], vis_angles [N_SENSORS ];
@@ -343,12 +353,17 @@ TEST(ReprojectResidualProps, SingleOutlierPoseStable) {
343353 solve_pose_bsvd (sensors , N_SENSORS , visible , n_vis , vis_angles , & recovered );
344354
345355 FLT err = pose_distance (& recovered , & obj2lh );
346- if (err > SINGLE_OUTLIER_POSE_TOL ) {
347- fprintf (stderr , "SingleOutlierPoseStable FAILED (seed=%u, trial=%d)\n" , seed , t );
348- fprintf (stderr , " n_vis=%d, corrupt_idx=%d, pose_distance=%.4f\n" ,
349- n_vis , corrupt_idx , err );
350- return -1 ;
351- }
356+ tested ++ ;
357+ if (err <= SINGLE_OUTLIER_POSE_TOL )
358+ within_tol ++ ;
359+ }
360+
361+ FLT rate = (FLT )within_tol / (FLT )tested ;
362+ if (rate < 0.95 ) {
363+ fprintf (stderr , "SingleOutlierPoseStable FAILED (seed=%u)\n" , seed );
364+ fprintf (stderr , " within-tolerance rate = %.1f%% (%d/%d), need >95%%\n" ,
365+ rate * 100.0 , within_tol , tested );
366+ return -1 ;
352367 }
353368 return 0 ;
354369}
@@ -362,6 +377,8 @@ TEST(ReprojectResidualProps, MultipleOutliersDegradeGracefully) {
362377 LinmathPoint3d sensors [N_SENSORS ];
363378 generate_sensor_positions (sensors , N_SENSORS );
364379
380+ int multi_tested = 0 , multi_within_tol = 0 ;
381+
365382 for (int t = 0 ; t < N_TRIALS ; t ++ ) {
366383 SurvivePose obj2lh ;
367384 SurviveAngleReading all_angles [N_SENSORS ], vis_angles [N_SENSORS ];
@@ -389,13 +406,17 @@ TEST(ReprojectResidualProps, MultipleOutliersDegradeGracefully) {
389406 solve_pose_bsvd (sensors , N_SENSORS , visible , n_vis , vis_angles , & recovered );
390407
391408 FLT err = pose_distance (& recovered , & obj2lh );
392- if (err > MULTI_OUTLIER_POSE_TOL ) {
393- fprintf (stderr , "MultipleOutliersDegradeGracefully FAILED (seed=%u, trial=%d)\n" ,
394- seed , t );
395- fprintf (stderr , " n_corrupt=%d, n_vis=%d, pose_distance=%.4f\n" ,
396- n_corrupt , n_vis , err );
397- return -1 ;
398- }
409+ multi_tested ++ ;
410+ if (err <= MULTI_OUTLIER_POSE_TOL )
411+ multi_within_tol ++ ;
412+ }
413+
414+ FLT multi_rate = (FLT )multi_within_tol / (FLT )multi_tested ;
415+ if (multi_rate < 0.95 ) {
416+ fprintf (stderr , "MultipleOutliersDegradeGracefully FAILED (seed=%u)\n" , seed );
417+ fprintf (stderr , " within-tolerance rate = %.1f%% (%d/%d), need >95%%\n" ,
418+ multi_rate * 100.0 , multi_within_tol , multi_tested );
419+ return -1 ;
399420 }
400421 return 0 ;
401422}
@@ -452,3 +473,74 @@ TEST(ReprojectResidualProps, ResidualIdentifiesCorruptedSensor) {
452473 }
453474 return 0 ;
454475}
476+
477+ /* 7. BSVD's "seed-quality" contract: per docs/high-level-design.md, BSVD is
478+ * the geometric seed that MPFIT's nonlinear refinement starts from ("SVD is
479+ * fast but ignores calibration; MPFIT is accurate but needs a good initial
480+ * guess"). MPFIT itself isn't reachable as a pure function (its entry point
481+ * is solve_global_scene(), which needs a full SurviveContext/GSS scene), so
482+ * this tests the contract MPFIT's convergence actually depends on: that a
483+ * clean BSVD solve lands close to ground truth across the realistic
484+ * sensor-count/distance envelope, not just the one fixed 12-sensor/1-4m
485+ * configuration CleanRoundtrip checks. If this regresses, MPFIT would be
486+ * starting from a worse seed in production, which would either slow
487+ * convergence or fail to converge at all — invisible to CleanRoundtrip
488+ * since it only samples one geometry. */
489+ TEST (ReprojectResidualProps , SeedQualityAcrossGeometry ) {
490+ unsigned seed = (unsigned )time (NULL );
491+ srand (seed );
492+
493+ static const int sensor_counts [] = {6 , 8 , 12 , 16 , 24 };
494+ static const FLT distances [] = {-0.5 , -1.0 , -2.0 , -4.0 , -8.0 };
495+
496+ for (size_t sc = 0 ; sc < sizeof (sensor_counts ) / sizeof (sensor_counts [0 ]); sc ++ ) {
497+ int n = sensor_counts [sc ];
498+ LinmathPoint3d sensors [32 ];
499+ generate_sensor_positions (sensors , n );
500+
501+ for (size_t dc = 0 ; dc < sizeof (distances ) / sizeof (distances [0 ]); dc ++ ) {
502+ BaseStationCal cal [2 ] = {0 };
503+ int trials_at_config = 0 , trials_ok = 0 ;
504+
505+ for (int t = 0 ; t < 200 ; t ++ ) {
506+ SurvivePose obj2lh ;
507+ obj2lh .Pos [0 ] = rand_range (-1.5 , 1.5 );
508+ obj2lh .Pos [1 ] = rand_range (-1.5 , 1.5 );
509+ obj2lh .Pos [2 ] = distances [dc ];
510+ rand_unit_quat (obj2lh .Rot );
511+
512+ SurviveAngleReading all_angles [32 ], vis_angles [32 ];
513+ LinmathPoint3d pts_lh [32 ];
514+ int visible [32 ];
515+
516+ reproject_sensors (cal , & obj2lh , sensors , n , all_angles , pts_lh );
517+ int n_vis = filter_visible (pts_lh , n , visible );
518+ if (n_vis < 6 )
519+ continue ;
520+ for (int i = 0 ; i < n_vis ; i ++ )
521+ memcpy (vis_angles [i ], all_angles [visible [i ]], sizeof (SurviveAngleReading ));
522+
523+ SurvivePose recovered ;
524+ solve_pose_bsvd (sensors , n , visible , n_vis , vis_angles , & recovered );
525+
526+ FLT err = pose_distance (& recovered , & obj2lh );
527+ trials_at_config ++ ;
528+ if (err <= POSE_TOL )
529+ trials_ok ++ ;
530+ }
531+
532+ if (trials_at_config == 0 )
533+ continue ;
534+
535+ FLT rate = (FLT )trials_ok / (FLT )trials_at_config ;
536+ if (rate < 0.90 ) {
537+ fprintf (stderr , "SeedQualityAcrossGeometry FAILED (seed=%u): n_sensors=%d dist=%.1f\n" ,
538+ seed , n , distances [dc ]);
539+ fprintf (stderr , " within POSE_TOL rate = %.1f%% (%d/%d), need >90%%\n" ,
540+ rate * 100.0 , trials_ok , trials_at_config );
541+ return -1 ;
542+ }
543+ }
544+ }
545+ return 0 ;
546+ }
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