FA-98821 / Tensor stride and reshape semantics / Open access
Tensor views: logical index bounds are checked per axis · case 01
logical index bounds are checked per axis.
ROOT CAUSE
The address calculation accepts coordinates outside the logical shape.
THE FAILURE
The address calculation accepts coordinates outside the logical shape.
Unsuccessful approach: Rejecting negative coordinates still lets indices at or above an axis size through.
Case contract
Return None if any index is outside [0,size); otherwise compute offset + dot(index,strides).
Why this case matters
Dense tensor views rely on consistent logical coordinates and physical storage addresses.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(shape, strides, offset, index):
return offset+sum(i*s for i,s in zip(index,strides))
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('last valid',solve([2,N],[N,1],5,[1,N-1]),5+2*N-1)
check('too large',solve([2,3],[3,1],0,[2,0]),None)
check('negative',solve([3],[1],0,[-1]),None)
check('origin',solve([2,2],[2,1],N,[0,0]),N)
check('rank mismatch',solve([2,2],[2,1],0,[1]),None)
check('scalar',solve([],[],7,[]),7)
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| last valid | 6 | 6 | Passed |
| too large | 6 | None | Failed |
| negative | -1 | None | Failed |
| origin | 1 | 1 | Passed |
| rank mismatch | 2 | None | Failed |
| scalar | 7 | 7 | Passed |
SHA-256 / 5c76f1c962d3829cb67e13632391d40de669bdd438922a5d5778c965f197db1b
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(shape, strides, offset, index):
if any(i<0 for i in index): return None
return offset+sum(i*s for i,s in zip(index,strides))
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('last valid',solve([2,N],[N,1],5,[1,N-1]),5+2*N-1)
check('too large',solve([2,3],[3,1],0,[2,0]),None)
check('negative',solve([3],[1],0,[-1]),None)
check('origin',solve([2,2],[2,1],N,[0,0]),N)
check('rank mismatch',solve([2,2],[2,1],0,[1]),None)
check('scalar',solve([],[],7,[]),7)
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| last valid | 6 | 6 | Passed |
| too large | 6 | None | Failed |
| negative | None | None | Passed |
| origin | 1 | 1 | Passed |
| rank mismatch | 2 | None | Failed |
| scalar | 7 | 7 | Passed |
SHA-256 / 609313bedb567942f5cba8315400131d9c1deaa8a504ce5e96985b12b1f93802
HELD IN THE MEMBER ARCHIVE
The verified repair and its recorded checks are member-only.
This mechanism has 6 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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Sign in to the archive ↗Verification & scope
Self-contained integer metadata models only; no production framework compatibility or performance claim. 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 2026-09-30T16:48:17.165200+00:00.
Case digest / d48550621fde747dd89be05c32b5b6c565289666e5e26bad528dac2f580239ae