{"abstract":"Shared expert output is lost when routed experts are empty.","category":"Mixture of experts dispatch","checks":6,"contract":"Given a shared scalar and routed (expert,weight,value) routes, return shared plus weighted route values.","contract_signature":"shared,routes","evaluation_group":"moe-shared-route-combine","failed_approach":"Adding the shared expert only when at least one conditional route survives still drops it on overflow.","family":"w3-mixture-of-experts-dispatch-shared-expert","id":"FA-100581","implementations":{"attempt":{"sha256":"35d09e99f0874f26aafae448fbda6aaa891623fdbb4714a339e9bc275c46d024","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(shared,routes):\n    return shared+sum(w*v for e,w,v in routes) if routes else 0\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nrows=[('a',0.5,N),('b',0.5,2*N)]\ncheck('shared and routes',solve(N,rows),N+1.5*N)\ncheck('no routes',solve(N,[]),N)\ncheck('one route',solve(2*N,[('x',1,N)]),3*N)\ncheck('zero shared',solve(0,rows),1.5*N)\ncheck('zero weights',solve(N,[('x',0,9)]),N)\ncheck('empty and zero',solve(0,[]),0)\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":"48aeeefb2c3b1b74eb3ad4270fc8e410e540760dc7e3488ef5a8fcbcd17747af","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(shared,routes):\n    return sum(w*v for e,w,v in routes)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nrows=[('a',0.5,N),('b',0.5,2*N)]\ncheck('shared and routes',solve(N,rows),N+1.5*N)\ncheck('no routes',solve(N,[]),N)\ncheck('one route',solve(2*N,[('x',1,N)]),3*N)\ncheck('zero shared',solve(0,rows),1.5*N)\ncheck('zero weights',solve(N,[('x',0,9)]),N)\ncheck('empty and zero',solve(0,[]),0)\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":"Inputs are finite toy scores and routes; the contract does not model a production model, accelerator, or learned routing quality. 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-mixture-of-experts-dispatch-shared-expert","generated_at":"2026-09-30T16:48:37.194461+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic toy router makes this dispatch decision independently inspectable.","root_cause":"The combine step only visits conditional routes.","sha256":"5ba233384284dea988989180da200acee8e73d1f366d798f44aa02cbf3abde4f","title":"Shared expert output is lost when routed experts are empty · 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":32.63,"exit_code":1,"observations":[{"actual":2.5,"check":"shared and routes","expected":2.5,"passed":true},{"actual":0,"check":"no routes","expected":1,"passed":false},{"actual":3,"check":"one route","expected":3,"passed":true},{"actual":1.5,"check":"zero shared","expected":1.5,"passed":true},{"actual":1,"check":"zero weights","expected":1,"passed":true},{"actual":0,"check":"empty and zero","expected":0,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"shared and routes\", \"actual\": 2.5, \"expected\": 2.5, \"passed\": true}, {\"check\": \"no routes\", \"actual\": 0, \"expected\": 1, \"passed\": false}, {\"check\": \"one route\", \"actual\": 3, \"expected\": 3, \"passed\": true}, {\"check\": \"zero shared\", \"actual\": 1.5, \"expected\": 1.5, \"passed\": true}, {\"check\": \"zero weights\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"empty and zero\", \"actual\": 0, \"expected\": 0, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":30.699,"exit_code":1,"observations":[{"actual":1.5,"check":"shared and routes","expected":2.5,"passed":false},{"actual":0,"check":"no routes","expected":1,"passed":false},{"actual":1,"check":"one route","expected":3,"passed":false},{"actual":1.5,"check":"zero shared","expected":1.5,"passed":true},{"actual":0,"check":"zero weights","expected":1,"passed":false},{"actual":0,"check":"empty and zero","expected":0,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"shared and routes\", \"actual\": 1.5, \"expected\": 2.5, \"passed\": false}, {\"check\": \"no routes\", \"actual\": 0, \"expected\": 1, \"passed\": false}, {\"check\": \"one route\", \"actual\": 1, \"expected\": 3, \"passed\": false}, {\"check\": \"zero shared\", \"actual\": 1.5, \"expected\": 1.5, \"passed\": true}, {\"check\": \"zero weights\", \"actual\": 0, \"expected\": 1, \"passed\": false}, {\"check\": \"empty and zero\", \"actual\": 0, \"expected\": 0, \"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."}}