{"abstract":"duplicate coordinates are overwritten instead of summed.","category":"Sparse tensor canonicalization","checks":7,"contract":"Entries are [row,column,value]. Return lexically sorted coordinate/value rows, summing all values at equal coordinates.","contract_signature":"entries","evaluation_group":"moe-route-contribution-merge","failed_approach":"Keeping the first value fixes overwrite order dependence but still omits subsequent contributions.","family":"w3-sparse-tensor-canonicalization-coo-duplicate-sum","id":"FA-100441","implementations":{"attempt":{"sha256":"dcb301e022d0fddf7cee4a1a717033d1fa6429d2da7f9cee5a8dc9e3395b2d08","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(entries):\n    out={}\n    for r,c,v in entries: out[(r,c)]=out.get((r,c),v)\n    return [[r,c,v] for (r,c),v in sorted(out.items())]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('duplicate add',solve([[0,1,N],[0,1,2]]),[[0,1,N+2]])\ncheck('several cells',solve([[1,0,3],[0,1,N],[1,0,4]]),[[0,1,N],[1,0,7]])\ncheck('empty',solve([]),[])\ncheck('single',solve([[N,0,5]]),[[N,0,5]])\ncheck('negative values',solve([[0,0,-N],[0,0,1]]),[[0,0,1-N]])\ncheck('cancel',solve([[0,0,N],[0,0,-N]]),[[0,0,0]])\ncheck('unique entries',solve([[1,2,4],[0,3,8]]),[[0,3,8],[1,2,4]])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"fc90576f96d576fcf695ec2dd1458565c35807cd25b0472399347a46069f686e","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(entries):\n    out={}\n    for r,c,v in entries: out[(r,c)]=v\n    return [[r,c,v] for (r,c),v in sorted(out.items())]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('duplicate add',solve([[0,1,N],[0,1,2]]),[[0,1,N+2]])\ncheck('several cells',solve([[1,0,3],[0,1,N],[1,0,4]]),[[0,1,N],[1,0,7]])\ncheck('empty',solve([]),[])\ncheck('single',solve([[N,0,5]]),[[N,0,5]])\ncheck('negative values',solve([[0,0,-N],[0,0,1]]),[[0,0,1-N]])\ncheck('cancel',solve([[0,0,N],[0,0,-N]]),[[0,0,0]])\ncheck('unique entries',solve([[1,2,4],[0,3,8]]),[[0,3,8],[1,2,4]])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"These are toy integer-valued COO or CSR contracts; they make no claim about a framework API, floating point policy, or large tensor performance. 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.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w3-sparse-tensor-canonicalization-coo-duplicate-sum","generated_at":"2026-09-30T16:48:35.784922+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A small offline sparse-array operation has explicit coordinate and storage semantics.","root_cause":"Direct assignment discards earlier contributions at a coordinate.","sha256":"cff760ae59bc69ead0a06f269986d8b39d0d9d0b61ad8eeaf0ec150546489f23","title":"Sparse tensor: duplicate coordinates are overwritten instead of summed · case 01","variant":1,"variant_policy":"The fixture code references N, supplied as 1 through 5. Fixed boundary checks may repeat. These records share one mechanism and must remain together in evaluation splits.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":28.858,"exit_code":1,"observations":[{"actual":[[0,1,1]],"check":"duplicate add","expected":[[0,1,3]],"passed":false},{"actual":[[0,1,1],[1,0,3]],"check":"several cells","expected":[[0,1,1],[1,0,7]],"passed":false},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[[1,0,5]],"check":"single","expected":[[1,0,5]],"passed":true},{"actual":[[0,0,-1]],"check":"negative values","expected":[[0,0,0]],"passed":false},{"actual":[[0,0,1]],"check":"cancel","expected":[[0,0,0]],"passed":false},{"actual":[[0,3,8],[1,2,4]],"check":"unique entries","expected":[[0,3,8],[1,2,4]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"duplicate add\", \"actual\": [[0, 1, 1]], \"expected\": [[0, 1, 3]], \"passed\": false}, {\"check\": \"several cells\", \"actual\": [[0, 1, 1], [1, 0, 3]], \"expected\": [[0, 1, 1], [1, 0, 7]], \"passed\": false}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"single\", \"actual\": [[1, 0, 5]], \"expected\": [[1, 0, 5]], \"passed\": true}, {\"check\": \"negative values\", \"actual\": [[0, 0, -1]], \"expected\": [[0, 0, 0]], \"passed\": false}, {\"check\": \"cancel\", \"actual\": [[0, 0, 1]], \"expected\": [[0, 0, 0]], \"passed\": false}, {\"check\": \"unique entries\", \"actual\": [[0, 3, 8], [1, 2, 4]], \"expected\": [[0, 3, 8], [1, 2, 4]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":28.844,"exit_code":1,"observations":[{"actual":[[0,1,2]],"check":"duplicate add","expected":[[0,1,3]],"passed":false},{"actual":[[0,1,1],[1,0,4]],"check":"several cells","expected":[[0,1,1],[1,0,7]],"passed":false},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[[1,0,5]],"check":"single","expected":[[1,0,5]],"passed":true},{"actual":[[0,0,1]],"check":"negative values","expected":[[0,0,0]],"passed":false},{"actual":[[0,0,-1]],"check":"cancel","expected":[[0,0,0]],"passed":false},{"actual":[[0,3,8],[1,2,4]],"check":"unique entries","expected":[[0,3,8],[1,2,4]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"duplicate add\", \"actual\": [[0, 1, 2]], \"expected\": [[0, 1, 3]], \"passed\": false}, {\"check\": \"several cells\", \"actual\": [[0, 1, 1], [1, 0, 4]], \"expected\": [[0, 1, 1], [1, 0, 7]], \"passed\": false}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"single\", \"actual\": [[1, 0, 5]], \"expected\": [[1, 0, 5]], \"passed\": true}, {\"check\": \"negative values\", \"actual\": [[0, 0, 1]], \"expected\": [[0, 0, 0]], \"passed\": false}, {\"check\": \"cancel\", \"actual\": [[0, 0, -1]], \"expected\": [[0, 0, 0]], \"passed\": false}, {\"check\": \"unique entries\", \"actual\": [[0, 3, 8], [1, 2, 4]], \"expected\": [[0, 3, 8], [1, 2, 4]], \"passed\": true}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}