FAILURE MAP
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FA-87706 / Collision detection broadphase / Open access

Swept box candidate test ignores touching bounds · case 01

Objects resting exactly at the sweep boundary are skipped.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The overlap test uses strict comparisons.

THE FAILURE

The overlap test uses strict comparisons.

Unsuccessful approach: Testing only the x interval admits distant objects.

Case contract

solve(box, vel, dt, margin, others): CCD broadphase bounds. Swept box = union of box at t and t+dt expanded by margin on all sides. fast = displacement length > half the smaller box extent. Return [swept rounded to 6, fast, sorted ids of others ([id,minx,miny,maxx,maxy]) overlapping the swept box with closed intervals].

Why this case matters

Broadphase stages decide which object pairs ever reach narrowphase; a wrong boundary, ordering or bookkeeping rule silently drops real contacts or floods the solver with false candidates.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(box, vel, dt, margin, others):
    dx, dy = vel[0] * dt, vel[1] * dt
    sw = [min(box[0], box[0] + dx) - margin, min(box[1], box[1] + dy) - margin,
          max(box[2], box[2] + dx) + margin, max(box[3], box[3] + dy) + margin]
    ext = min(box[2] - box[0], box[3] - box[1])
    fast = math.hypot(dx, dy) > 0.5 * ext
    hits = sorted(o[0] for o in others if o[1] < sw[2] and sw[0] < o[3] and o[2] < sw[3] and sw[1] < o[4])
    return [[round(c, 6) for c in sw], fast, hits]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[[[1, 1, 1.5, 4], [8, 16], 0.25, 0.5, [[15, 3, 0, 5, 2], [18, 4, 8, 4, 8], [28, 8, 4, 9, 4], [19, 0, -3, 1, -2], [16, -5, 7, -5, 8]]], [[0.5, 0.5, 4.0, 8.5], True, [15, 18]]], [[[-4, -4, -3.5, -3.5], [-12, 16], 0.125, 0.0, [[20, 8, 0, 10, 0], [1, -8, 8, -8, 8], [29, 1, 2, 3, 2]]], [[-5.5, -4.0, -3.5, -1.5], True, []]], [[[3, -4, 5, -3.5], [2, -3], 0.125, 0.25, [[7, -7, -3, -6, -1], [3, 3, -3, 5, -3], [24, 5, -7, 7, -6]]], [[2.75, -4.625, 5.5, -3.25], True, []]], [[[0, 0, 0.5, 1], [-12, 16], 0.125, 0.5, [[17, 4, 1, 5, 2], [13, 6, 7, 6, 9], [2, 1, 0, 2, 0], [26, -7, 1, -6, 1], [27, 2, 3, 2, 4]]], [[-2.0, -0.5, 1.0, 3.5], True, [2]]], [[[2, 4, 4, 5], [8, 3], 0.0625, 0.0, [[4, -5, 1, -4, 2], [8, 2, -8, 4, -6]]], [[2.0, 4.0, 4.5, 5.1875], True, []]], [[[-2, 2, 0, 2.5], [-2, 16], 0.25, 0.5, [[27, 2, 1, 2, 3], [24, 7, -8, 7, -7], [7, -1, 7, 0, 8], [14, -2, 6, -1, 7], [18, 2, -8, 2, -7]]], [[-3.0, 1.5, 0.5, 7.0], True, [7, 14]]], [[[1, -2, 2, -1], [-12, 16], 0.125, 0.25, [[3, -4, 5, -4, 6], [10, -1, 8, -1, 9], [8, 0, 5, 2, 5]]], [[-0.75, -2.25, 2.25, 1.25], True, []]], [[[0, 4, 2, 5], [8, 3], 0.25, 0.5, [[4, -6, 8, -6, 10], [19, 2, -1, 3, 1], [25, -5, 6, -4, 7], [20, 2, -5, 2, -3]]], [[-0.5, 3.5, 4.5, 6.25], True, []]]], [[[[3, -2, 3.5, -1.5], [30, 0], 0.25, 0.0, [[7, -1, 1, -1, 1], [24, -5, 4, -4, 5], [17, 3, 1, 3, 2]]], [[3.0, -2.0, 11.0, -1.5], True, []]], [[[2, -2, 2.5, 1], [-2, -20], 0.25, 0.0, [[27, 4, 3, 5, 5], [24, 2, 4, 4, 4]]], [[1.5, -7.0, 2.5, 1.0], True, []]], [[[-2, 4, 0, 7], [2, -20], 0.125, 0.5, [[4, -1, -1, 1, -1], [15, 8, 4, 8, 6], [18, -7, 6, -6, 8], [6, -5, 4, -3, 6], [12, -8, 0, -8, 0]]], [[-2.5, 1.0, 0.75, 7.5], True, []]], [[[4, 0, 4.5, 0.5], [0, -20], 0.0625, 0.25, [[19, -3, -8, -2, -8], [13, -5, -1, -3, -1], [29, -7, 2, -6, 2], [14, -8, 7, -7, 7], [10, 3, -5, 5, -3]]], [[3.75, -1.5, 4.75, 0.75], True, []]], [[[2, 2, 2.5, 2.5], [8, 0], 0.25, 0.0, [[19, 0, 6, 2, 8], [10, 2, 4, 4, 5], [22, 5, 4, 6, 5], [28, -3, 3, -2, 3], [2, -8, 7, -8, 8]]], [[2.0, 2.0, 4.5, 2.5], True, []]], [[[4, -3, 4.5, -2.5], [-2, -20], 0.25, 0.5, [[21, 7, 2, 9, 3], [16, 3, -5, 3, -5], [7, 0, 7, 2, 7], [23, 7, -5, 8, -3]]], [[3.0, -8.5, 5.0, -2.0], True, [16]]], [[[-3, -3, -1, -2], [-12, 3], 0.0625, 0.5, [[3, -3, -5, -1, -5], [24, -6, -2, -5, -1]]], [[-4.25, -3.5, -0.5, -1.3125], True, []]], [[[-4, 2, -2, 2.5], [-12, 3], 0.25, 0.0, [[13, 2, 8, 3, 9], [18, 2, -8, 4, -7], [28, -7, 3, -7, 4], [3, 5, -6, 5, -4]]], [[-7.0, 2.0, -2.0, 3.25], True, [28]]]], [[[[3, -2, 3.5, -1], [2, 0], 0.125, 0.0, [[7, 3, 4, 3, 6], [18, 0, -1, 2, 0], [23, -3, -8, -1, -8]]], [[3.0, -2.0, 3.75, -1.0], False, []]], [[[-3, -4, -2.5, -3], [-12, -20], 0.0625, 0.5, [[20, 2, 1, 2, 1], [8, -1, 5, -1, 7]]], [[-4.25, -5.75, -2.0, -2.5], True, []]], [[[3, -1, 4, 2], [0, -3], 0.125, 0.0, [[21, 5, 8, 7, 10], [9, -6, 3, -6, 3], [11, 4, -2, 5, -1]]], [[3.0, -1.375, 4.0, 2.0], False, [11]]], [[[-3, -3, -1, 0], [8, -3], 0.25, 0.0, [[26, 5, -2, 6, 0], [28, 6, 0, 8, 0], [2, 1, -3, 1, -3], [16, 3, 7, 4, 8]]], [[-3.0, -3.75, 1.0, 0.0], True, [2]]], [[[-2, -2, -1, -1.5], [-2, -3], 0.0625, 0.25, [[14, 0, 7, 0, 8], [20, -2, 2, -1, 4]]], [[-2.375, -2.4375, -0.75, -1.25], False, []]], [[[-3, -2, -2, -1], [-2, -3], 0.25, 0.5, [[29, -1, -6, 1, -6], [3, -3, -5, -2, -4], [13, -8, 0, -6, 0]]], [[-4.0, -3.25, -1.5, -0.5], True, []]], [[[0, 0, 1, 3], [2, 0], 0.125, 0.25, [[17, 8, -3, 8, -1], [4, 7, 2, 8, 4], [1, 6, 2, 8, 4], [11, 8, 5, 10, 7], [8, -3, 5, -2, 5]]], [[-0.25, -0.25, 1.5, 3.25], False, []]], [[[0, 3, 0.5, 3.5], [8, 16], 0.0625, 0.0, [[28, -6, -3, -5, -2], [9, -7, -1, -5, -1], [19, -8, -3, -6, -1], [26, 0, 1, 0, 3], [13, -6, -2, -5, 0]]], [[0.0, 3.0, 1.0, 4.5], True, [26]]]], [[[[-3, -3, -2.5, -2.5], [2, 16], 0.25, 0.25, [[7, -5, 6, -5, 8], [16, -1, 7, 0, 9], [26, 4, 7, 6, 8], [27, 4, 4, 6, 5]]], [[-3.25, -3.25, -1.75, 1.75], True, []]], [[[4, -1, 6, -0.5], [0, 3], 0.125, 0.25, [[28, 8, 6, 10, 7], [27, -7, 4, -6, 5], [11, 6, 6, 8, 8], [9, -4, 2, -4, 2], [4, 4, -4, 6, -3]]], [[3.75, -1.25, 6.25, 0.125], True, []]], [[[3, 2, 5, 5], [-12, -3], 0.0625, 0.25, [[16, 1, -1, 2, 1]]], [[2.0, 1.5625, 5.25, 5.25], False, []]], [[[0, 2, 1, 3], [0, -3], 0.0625, 0.0, [[5, -4, 2, -4, 4], [10, 1, 3, 1, 4], [15, 0, 2, 1, 4], [12, -4, -4, -3, -4]]], [[0.0, 1.8125, 1.0, 3.0], False, [10, 15]]], [[[-3, -1, -2, -0.5], [-12, -3], 0.25, 0.5, [[25, -1, 6, -1, 8], [6, -4, 0, -2, 1], [5, -6, 7, -5, 7], [27, 5, 7, 5, 7]]], [[-6.5, -2.25, -1.5, 0.0], True, [6]]], [[[-4, -1, -3, -0.5], [-12, -3], 0.25, 0.25, [[5, 3, -4, 5, -3], [15, -5, -2, -5, -2], [1, 3, -1, 5, 1]]], [[-7.25, -2.0, -2.75, -0.25], True, [15]]], [[[-3, -4, -1, -1], [-12, -20], 0.0625, 0.25, [[11, 5, -8, 6, -7]]], [[-4.0, -5.5, -0.75, -0.75], True, []]], [[[3, 0, 3.5, 3], [0, 0], 0.25, 0.0, [[4, 1, -4, 3, -3], [6, -7, -1, -5, 0]]], [[3.0, 0.0, 3.5, 3.0], False, []]]], [[[[-2, 4, 0, 4.5], [30, 3], 0.125, 0.0, [[9, -1, -5, -1, -4], [4, 6, -1, 6, -1]]], [[-2.0, 4.0, 3.75, 4.875], True, []]], [[[-4, 3, -3, 6], [0, 0], 0.125, 0.0, [[1, -7, -5, -6, -3], [28, -8, 4, -6, 5], [29, -4, 2, -3, 3], [23, 8, -7, 8, -6], [7, 1, -2, 2, -2]]], [[-4.0, 3.0, -3.0, 6.0], False, [29]]], [[[4, -3, 6, 0], [30, -20], 0.25, 0.25, [[25, -8, 3, -6, 3], [12, 6, 1, 8, 1], [20, -1, -6, -1, -6], [5, 7, 4, 7, 4], [18, 3, 7, 4, 7]]], [[3.75, -8.25, 13.75, 0.25], True, []]], [[[0, 4, 2, 4.5], [2, 16], 0.125, 0.0, [[8, 2, 4, 3, 4], [4, 2, -4, 2, -2], [19, 8, 6, 10, 6]]], [[0.0, 4.0, 2.25, 6.5], True, [8]]], [[[-3, 0, -2, 0.5], [0, -20], 0.125, 0.25, [[18, -2, -7, -1, -7], [9, 8, 7, 10, 8]]], [[-3.25, -2.75, -1.75, 0.75], True, []]], [[[2, 2, 4, 2.5], [-12, -3], 0.25, 0.25, [[5, -1, -7, -1, -6], [6, 0, 4, 0, 6]]], [[-1.25, 1.0, 4.25, 2.75], True, []]], [[[-3, 4, -2, 5], [2, 16], 0.25, 0.5, [[16, 1, 6, 2, 6], [24, 4, 4, 5, 5], [28, 0, 7, 2, 7], [29, -5, 8, -5, 8]]], [[-3.5, 3.5, -1.0, 9.5], True, []]], [[[0, 3, 1, 3.5], [-2, 16], 0.0625, 0.0, [[24, 3, -7, 5, -5], [4, 3, -1, 4, -1]]], [[-0.125, 3.0, 1.0, 4.5], True, []]]]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("case %d" % i, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
case 0[[0.5, 0.5, 4.0, 8.5], True, [15]][[0.5, 0.5, 4.0, 8.5], True, [15, 18]]Failed
case 1[[-5.5, -4.0, -3.5, -1.5], True, []][[-5.5, -4.0, -3.5, -1.5], True, []]Passed
case 2[[2.75, -4.625, 5.5, -3.25], True, []][[2.75, -4.625, 5.5, -3.25], True, []]Passed
case 3[[-2.0, -0.5, 1.0, 3.5], True, []][[-2.0, -0.5, 1.0, 3.5], True, [2]]Failed
case 4[[2.0, 4.0, 4.5, 5.1875], True, []][[2.0, 4.0, 4.5, 5.1875], True, []]Passed
case 5[[-3.0, 1.5, 0.5, 7.0], True, [14]][[-3.0, 1.5, 0.5, 7.0], True, [7, 14]]Failed
case 6[[-0.75, -2.25, 2.25, 1.25], True, []][[-0.75, -2.25, 2.25, 1.25], True, []]Passed
case 7[[-0.5, 3.5, 4.5, 6.25], True, []][[-0.5, 3.5, 4.5, 6.25], True, []]Passed

SHA-256 / 93979af9e5969b259a1a11d77643a299685c37b4ba11b77f2e2812278ac575d7

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(box, vel, dt, margin, others):
    dx, dy = vel[0] * dt, vel[1] * dt
    sw = [min(box[0], box[0] + dx) - margin, min(box[1], box[1] + dy) - margin,
          max(box[2], box[2] + dx) + margin, max(box[3], box[3] + dy) + margin]
    ext = min(box[2] - box[0], box[3] - box[1])
    fast = math.hypot(dx, dy) > 0.5 * ext
    hits = sorted(o[0] for o in others if o[1] <= sw[2] and sw[0] <= o[3])
    return [[round(c, 6) for c in sw], fast, hits]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[[[1, 1, 1.5, 4], [8, 16], 0.25, 0.5, [[15, 3, 0, 5, 2], [18, 4, 8, 4, 8], [28, 8, 4, 9, 4], [19, 0, -3, 1, -2], [16, -5, 7, -5, 8]]], [[0.5, 0.5, 4.0, 8.5], True, [15, 18]]], [[[-4, -4, -3.5, -3.5], [-12, 16], 0.125, 0.0, [[20, 8, 0, 10, 0], [1, -8, 8, -8, 8], [29, 1, 2, 3, 2]]], [[-5.5, -4.0, -3.5, -1.5], True, []]], [[[3, -4, 5, -3.5], [2, -3], 0.125, 0.25, [[7, -7, -3, -6, -1], [3, 3, -3, 5, -3], [24, 5, -7, 7, -6]]], [[2.75, -4.625, 5.5, -3.25], True, []]], [[[0, 0, 0.5, 1], [-12, 16], 0.125, 0.5, [[17, 4, 1, 5, 2], [13, 6, 7, 6, 9], [2, 1, 0, 2, 0], [26, -7, 1, -6, 1], [27, 2, 3, 2, 4]]], [[-2.0, -0.5, 1.0, 3.5], True, [2]]], [[[2, 4, 4, 5], [8, 3], 0.0625, 0.0, [[4, -5, 1, -4, 2], [8, 2, -8, 4, -6]]], [[2.0, 4.0, 4.5, 5.1875], True, []]], [[[-2, 2, 0, 2.5], [-2, 16], 0.25, 0.5, [[27, 2, 1, 2, 3], [24, 7, -8, 7, -7], [7, -1, 7, 0, 8], [14, -2, 6, -1, 7], [18, 2, -8, 2, -7]]], [[-3.0, 1.5, 0.5, 7.0], True, [7, 14]]], [[[1, -2, 2, -1], [-12, 16], 0.125, 0.25, [[3, -4, 5, -4, 6], [10, -1, 8, -1, 9], [8, 0, 5, 2, 5]]], [[-0.75, -2.25, 2.25, 1.25], True, []]], [[[0, 4, 2, 5], [8, 3], 0.25, 0.5, [[4, -6, 8, -6, 10], [19, 2, -1, 3, 1], [25, -5, 6, -4, 7], [20, 2, -5, 2, -3]]], [[-0.5, 3.5, 4.5, 6.25], True, []]]], [[[[3, -2, 3.5, -1.5], [30, 0], 0.25, 0.0, [[7, -1, 1, -1, 1], [24, -5, 4, -4, 5], [17, 3, 1, 3, 2]]], [[3.0, -2.0, 11.0, -1.5], True, []]], [[[2, -2, 2.5, 1], [-2, -20], 0.25, 0.0, [[27, 4, 3, 5, 5], [24, 2, 4, 4, 4]]], [[1.5, -7.0, 2.5, 1.0], True, []]], [[[-2, 4, 0, 7], [2, -20], 0.125, 0.5, [[4, -1, -1, 1, -1], [15, 8, 4, 8, 6], [18, -7, 6, -6, 8], [6, -5, 4, -3, 6], [12, -8, 0, -8, 0]]], [[-2.5, 1.0, 0.75, 7.5], True, []]], [[[4, 0, 4.5, 0.5], [0, -20], 0.0625, 0.25, [[19, -3, -8, -2, -8], [13, -5, -1, -3, -1], [29, -7, 2, -6, 2], [14, -8, 7, -7, 7], [10, 3, -5, 5, -3]]], [[3.75, -1.5, 4.75, 0.75], True, []]], [[[2, 2, 2.5, 2.5], [8, 0], 0.25, 0.0, [[19, 0, 6, 2, 8], [10, 2, 4, 4, 5], [22, 5, 4, 6, 5], [28, -3, 3, -2, 3], [2, -8, 7, -8, 8]]], [[2.0, 2.0, 4.5, 2.5], True, []]], [[[4, -3, 4.5, -2.5], [-2, -20], 0.25, 0.5, [[21, 7, 2, 9, 3], [16, 3, -5, 3, -5], [7, 0, 7, 2, 7], [23, 7, -5, 8, -3]]], [[3.0, -8.5, 5.0, -2.0], True, [16]]], [[[-3, -3, -1, -2], [-12, 3], 0.0625, 0.5, [[3, -3, -5, -1, -5], [24, -6, -2, -5, -1]]], [[-4.25, -3.5, -0.5, -1.3125], True, []]], [[[-4, 2, -2, 2.5], [-12, 3], 0.25, 0.0, [[13, 2, 8, 3, 9], [18, 2, -8, 4, -7], [28, -7, 3, -7, 4], [3, 5, -6, 5, -4]]], [[-7.0, 2.0, -2.0, 3.25], True, [28]]]], [[[[3, -2, 3.5, -1], [2, 0], 0.125, 0.0, [[7, 3, 4, 3, 6], [18, 0, -1, 2, 0], [23, -3, -8, -1, -8]]], [[3.0, -2.0, 3.75, -1.0], False, []]], [[[-3, -4, -2.5, -3], [-12, -20], 0.0625, 0.5, [[20, 2, 1, 2, 1], [8, -1, 5, -1, 7]]], [[-4.25, -5.75, -2.0, -2.5], True, []]], [[[3, -1, 4, 2], [0, -3], 0.125, 0.0, [[21, 5, 8, 7, 10], [9, -6, 3, -6, 3], [11, 4, -2, 5, -1]]], [[3.0, -1.375, 4.0, 2.0], False, [11]]], [[[-3, -3, -1, 0], [8, -3], 0.25, 0.0, [[26, 5, -2, 6, 0], [28, 6, 0, 8, 0], [2, 1, -3, 1, -3], [16, 3, 7, 4, 8]]], [[-3.0, -3.75, 1.0, 0.0], True, [2]]], [[[-2, -2, -1, -1.5], [-2, -3], 0.0625, 0.25, [[14, 0, 7, 0, 8], [20, -2, 2, -1, 4]]], [[-2.375, -2.4375, -0.75, -1.25], False, []]], [[[-3, -2, -2, -1], [-2, -3], 0.25, 0.5, [[29, -1, -6, 1, -6], [3, -3, -5, -2, -4], [13, -8, 0, -6, 0]]], [[-4.0, -3.25, -1.5, -0.5], True, []]], [[[0, 0, 1, 3], [2, 0], 0.125, 0.25, [[17, 8, -3, 8, -1], [4, 7, 2, 8, 4], [1, 6, 2, 8, 4], [11, 8, 5, 10, 7], [8, -3, 5, -2, 5]]], [[-0.25, -0.25, 1.5, 3.25], False, []]], [[[0, 3, 0.5, 3.5], [8, 16], 0.0625, 0.0, [[28, -6, -3, -5, -2], [9, -7, -1, -5, -1], [19, -8, -3, -6, -1], [26, 0, 1, 0, 3], [13, -6, -2, -5, 0]]], [[0.0, 3.0, 1.0, 4.5], True, [26]]]], [[[[-3, -3, -2.5, -2.5], [2, 16], 0.25, 0.25, [[7, -5, 6, -5, 8], [16, -1, 7, 0, 9], [26, 4, 7, 6, 8], [27, 4, 4, 6, 5]]], [[-3.25, -3.25, -1.75, 1.75], True, []]], [[[4, -1, 6, -0.5], [0, 3], 0.125, 0.25, [[28, 8, 6, 10, 7], [27, -7, 4, -6, 5], [11, 6, 6, 8, 8], [9, -4, 2, -4, 2], [4, 4, -4, 6, -3]]], [[3.75, -1.25, 6.25, 0.125], True, []]], [[[3, 2, 5, 5], [-12, -3], 0.0625, 0.25, [[16, 1, -1, 2, 1]]], [[2.0, 1.5625, 5.25, 5.25], False, []]], [[[0, 2, 1, 3], [0, -3], 0.0625, 0.0, [[5, -4, 2, -4, 4], [10, 1, 3, 1, 4], [15, 0, 2, 1, 4], [12, -4, -4, -3, -4]]], [[0.0, 1.8125, 1.0, 3.0], False, [10, 15]]], [[[-3, -1, -2, -0.5], [-12, -3], 0.25, 0.5, [[25, -1, 6, -1, 8], [6, -4, 0, -2, 1], [5, -6, 7, -5, 7], [27, 5, 7, 5, 7]]], [[-6.5, -2.25, -1.5, 0.0], True, [6]]], [[[-4, -1, -3, -0.5], [-12, -3], 0.25, 0.25, [[5, 3, -4, 5, -3], [15, -5, -2, -5, -2], [1, 3, -1, 5, 1]]], [[-7.25, -2.0, -2.75, -0.25], True, [15]]], [[[-3, -4, -1, -1], [-12, -20], 0.0625, 0.25, [[11, 5, -8, 6, -7]]], [[-4.0, -5.5, -0.75, -0.75], True, []]], [[[3, 0, 3.5, 3], [0, 0], 0.25, 0.0, [[4, 1, -4, 3, -3], [6, -7, -1, -5, 0]]], [[3.0, 0.0, 3.5, 3.0], False, []]]], [[[[-2, 4, 0, 4.5], [30, 3], 0.125, 0.0, [[9, -1, -5, -1, -4], [4, 6, -1, 6, -1]]], [[-2.0, 4.0, 3.75, 4.875], True, []]], [[[-4, 3, -3, 6], [0, 0], 0.125, 0.0, [[1, -7, -5, -6, -3], [28, -8, 4, -6, 5], [29, -4, 2, -3, 3], [23, 8, -7, 8, -6], [7, 1, -2, 2, -2]]], [[-4.0, 3.0, -3.0, 6.0], False, [29]]], [[[4, -3, 6, 0], [30, -20], 0.25, 0.25, [[25, -8, 3, -6, 3], [12, 6, 1, 8, 1], [20, -1, -6, -1, -6], [5, 7, 4, 7, 4], [18, 3, 7, 4, 7]]], [[3.75, -8.25, 13.75, 0.25], True, []]], [[[0, 4, 2, 4.5], [2, 16], 0.125, 0.0, [[8, 2, 4, 3, 4], [4, 2, -4, 2, -2], [19, 8, 6, 10, 6]]], [[0.0, 4.0, 2.25, 6.5], True, [8]]], [[[-3, 0, -2, 0.5], [0, -20], 0.125, 0.25, [[18, -2, -7, -1, -7], [9, 8, 7, 10, 8]]], [[-3.25, -2.75, -1.75, 0.75], True, []]], [[[2, 2, 4, 2.5], [-12, -3], 0.25, 0.25, [[5, -1, -7, -1, -6], [6, 0, 4, 0, 6]]], [[-1.25, 1.0, 4.25, 2.75], True, []]], [[[-3, 4, -2, 5], [2, 16], 0.25, 0.5, [[16, 1, 6, 2, 6], [24, 4, 4, 5, 5], [28, 0, 7, 2, 7], [29, -5, 8, -5, 8]]], [[-3.5, 3.5, -1.0, 9.5], True, []]], [[[0, 3, 1, 3.5], [-2, 16], 0.0625, 0.0, [[24, 3, -7, 5, -5], [4, 3, -1, 4, -1]]], [[-0.125, 3.0, 1.0, 4.5], True, []]]]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("case %d" % i, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
case 0[[0.5, 0.5, 4.0, 8.5], True, [15, 18, 19]][[0.5, 0.5, 4.0, 8.5], True, [15, 18]]Failed
case 1[[-5.5, -4.0, -3.5, -1.5], True, []][[-5.5, -4.0, -3.5, -1.5], True, []]Passed
case 2[[2.75, -4.625, 5.5, -3.25], True, [3, 24]][[2.75, -4.625, 5.5, -3.25], True, []]Failed
case 3[[-2.0, -0.5, 1.0, 3.5], True, [2]][[-2.0, -0.5, 1.0, 3.5], True, [2]]Passed
case 4[[2.0, 4.0, 4.5, 5.1875], True, [8]][[2.0, 4.0, 4.5, 5.1875], True, []]Failed
case 5[[-3.0, 1.5, 0.5, 7.0], True, [7, 14]][[-3.0, 1.5, 0.5, 7.0], True, [7, 14]]Passed
case 6[[-0.75, -2.25, 2.25, 1.25], True, [8]][[-0.75, -2.25, 2.25, 1.25], True, []]Failed
case 7[[-0.5, 3.5, 4.5, 6.25], True, [19, 20]][[-0.5, 3.5, 4.5, 6.25], True, []]Failed

SHA-256 / 7f17b29de05100f5fa58e95ddfba531dbb79290188923915a7813e1235134167

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 8 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

A deterministic bounded teaching model with stipulated toy conventions; not a production physics engine or spatial index. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:51:01.273942+00:00.

Case digest / 17fb8f9f79af2de7523555b9b8204de75f64ac1e5b0107b0621344992f401cf2