Upload 2 files

quread/trends.py

@@ -274,6 +274,34 @@ def compute_drift_alerts(
     return alerts
 
 
+def compute_snapshot_delta(
+    series: np.ndarray,
+    metric_key: str,
+    *,
+    from_index: int,
+    to_index: int,
+) -> Tuple[np.ndarray, np.ndarray, int, int]:
+    arr = np.asarray(series, dtype=float)
+    if arr.ndim != 2:
+        raise ValueError("series must be a 2D array of shape [snapshots, qubits].")
+    points = int(arr.shape[0])
+    if points < 2:
+        raise ValueError("Need at least 2 snapshots to compute delta.")
+
+    i = int(np.clip(int(from_index), 0, points - 1))
+    j = int(np.clip(int(to_index), 0, points - 1))
+    if i == j:
+        if j == points - 1:
+            i = max(0, j - 1)
+        else:
+            j = min(points - 1, i + 1)
+
+    raw_delta = arr[j] - arr[i]
+    risk_series = _risk_transform(arr, _resolve_metric(metric_key))
+    risk_delta = risk_series[j] - risk_series[i]
+    return np.asarray(raw_delta, dtype=float), np.asarray(risk_delta, dtype=float), int(i), int(j)
+
+
 def alerts_to_csv(alerts: List[Dict[str, Any]]) -> str:
     out = io.StringIO()
     writer = csv.writer(out)