Demo · intentionally changed circuit
Sample regression report.
Measurement details
Measured locally on 8 September 2026 with Qiskit 2.5.2. The candidate deliberately removes CX from a Bell-state circuit. This is an intentional example, not a customer incident or a Qiskit bug.
| Check | Observed | Limit | Status |
|---|---|---|---|
| Two-qubit gates | 1 → 0 | ≤ 1 | WITHIN_POLICY |
| Distribution distance (TV) | 0.5 | ≤ 0.05 | REGRESSION |
Exact ideal probabilities · no shots
Interpretation & next step
A selected limit was exceeded.
Inspect the failing checks and reproduce the change locally. Review intended changes before updating a policy or baseline.
What changed
Values, circuit instructions and environment details stay in your local full report.
- circuit_sha256
Scope & provenance
Client-reported local results. KetQat checks the summary schema, arithmetic and verdict consistency; it does not rerun private circuits. Computational-basis distributions on zero input do not establish circuit equivalence or whole-program correctness. These checks measure no hardware performance, runtime or cost.
Sampled intervals cover one report. Repeated comparisons need an error budget across reports; repeated sampling until a pass is not valid evidence. A matching hash identifies a record and is not independent verification.
Policy and record fingerprints
{
"case_key": "c8adda57bfc3a5bf5448630744b8a4baa0342a78f59623795ee68d20c4f0bdd1",
"baseline_sha256": "4817acddeae9cd71dcf87d5056fbe319455318a3084c060aa954a6ade8ee8223",
"candidate_sha256": "b6824e6fef2edfe4ac204815102706675c79f9ff59081c0bb95b7b33bd1be504",
"policy": {
"schema_version": "ketqat.regression.policy.v1",
"changed_axes": [
"source_commit",
"circuit"
],
"resources": {
"two_qubit_gates": {
"absolute_increase": 0,
"relative_increase": 0
}
},
"max_total_variation": 0.05,
"family_alpha": 0.01
}
}The lower two-qubit gate count is within the resource limit. The distribution distance exceeds 0.05, so the combined verdict is REGRESSION. Fewer gates alone would not establish a useful improvement.