Fix review nits.

cirq-core/cirq/devices/noise_utils.py

@@ -106,8 +106,11 @@ def decay_constant_to_xeb_fidelity(decay_constant: float, num_qubits: int = 2) -
     """Calculates the XEB fidelity from the depolarization decay constant.
 
     Args:
-        decay_constant: Depolarization decay constant
-        num_qubits: Number of qubits
+        decay_constant: Depolarization decay constant.
+        num_qubits: Number of qubits.
+
+    Returns:
+        Calculated XEB fidelity.
     """
     N = 2 ** num_qubits
     return 1 - ((1 - decay_constant) * (1 - 1 / N))
@@ -117,8 +120,11 @@ def decay_constant_to_pauli_error(decay_constant: float, num_qubits: int = 1) ->
     """Calculates pauli error from the depolarization decay constant.
 
     Args:
-        decay_constant: Depolarization decay constant
-        num_qubits: Number of qubits
+        decay_constant: Depolarization decay constant.
+        num_qubits: Number of qubits.
+
+    Returns:
+        Calculated Pauli error.
     """
     N = 2 ** num_qubits
     return (1 - decay_constant) * (1 - 1 / N / N)
@@ -128,8 +134,11 @@ def pauli_error_to_decay_constant(pauli_error: float, num_qubits: int = 1) -> fl
     """Calculates depolarization decay constant from pauli error.
 
     Args:
-        pauli_error: The pauli error
-        num_qubits: Number of qubits
+        pauli_error: The pauli error.
+        num_qubits: Number of qubits.
+
+    Returns:
+        Calculated depolarization decay constant.
     """
     N = 2 ** num_qubits
     return 1 - (pauli_error / (1 - 1 / N / N))
@@ -139,68 +148,83 @@ def xeb_fidelity_to_decay_constant(xeb_fidelity: float, num_qubits: int = 2) ->
     """Calculates the depolarization decay constant from XEB fidelity.
 
     Args:
-        xeb_fidelity: The XEB fidelity
-        num_qubits: Number of qubits
+        xeb_fidelity: The XEB fidelity.
+        num_qubits: Number of qubits.
+
+    Returns:
+        Calculated depolarization decay constant.
     """
     N = 2 ** num_qubits
     return 1 - (1 - xeb_fidelity) / (1 - 1 / N)
 
 
-def pauli_error_from_t1(t: float, t1_ns: float) -> float:
+def pauli_error_from_t1(t_ns: float, t1_ns: float) -> float:
     """Calculates the pauli error from T1 decay constant.
 
     This computes error for a specific duration, `t`.
 
     Args:
-        t: The duration of the gate
-        t1_ns: The T1 decay constant in ns
+        t_ns: The duration of the gate in ns.
+        t1_ns: The T1 decay constant in ns.
+
+    Returns:
+        Calculated Pauli error resulting from T1 decay.
     """
     t2 = 2 * t1_ns
-    return (1 - np.exp(-t / t2)) / 2 + (1 - np.exp(-t / t1_ns)) / 4
+    return (1 - np.exp(-t_ns / t2)) / 2 + (1 - np.exp(-t_ns / t1_ns)) / 4
 
 
-def pauli_error_from_depolarization(t: float, t1_ns: float, pauli_error: float = 0) -> float:
+def pauli_error_from_depolarization(t_ns: float, t1_ns: float, pauli_error: float = 0) -> float:
     """Calculates the amount of pauli error from depolarization.
 
     This computes non-T1 error for a specific duration, `t`. If pauli error
     from T1 decay is more than total pauli error, this returns zero; otherwise,
     it returns the portion of pauli error not attributable to T1 error.
 
     Args:
-        t: The duration of the gate
-        t1_ns: The T1 decay constant in ns
-        pauli_error: The pauli error
+        t_ns: The duration of the gate in ns.
+        t1_ns: The T1 decay constant in ns.
+        pauli_error: The total pauli error.
+
+    Returns:
+        Calculated Pauli error resulting from depolarization.
     """
-    t1_pauli_error = pauli_error_from_t1(t, t1_ns)
+    t1_pauli_error = pauli_error_from_t1(t_ns, t1_ns)
     if pauli_error >= t1_pauli_error:
         return pauli_error - t1_pauli_error
-    else:
-        warnings.warn("Pauli error from T1 decay is greater than total Pauli error", RuntimeWarning)
-        return 0
+
+    warnings.warn("Pauli error from T1 decay is greater than total Pauli error", RuntimeWarning)
+    return 0
 
 
 def average_error(decay_constant: float, num_qubits: int = 1) -> float:
     """Calculates the average error from the depolarization decay constant.
 
     Args:
-        decay_constant: Depolarization decay constant
-        num_qubits: Number of qubits
+        decay_constant: Depolarization decay constant.
+        num_qubits: Number of qubits.
+
+    Returns:
+        Calculated average error.
     """
     N = 2 ** num_qubits
     return (1 - decay_constant) * (1 - 1 / N)
 
 
-def decoherence_pauli_error(T1_ns: float, Tphi_ns: float, gate_time_ns: float) -> float:
+def decoherence_pauli_error(t1_ns: float, tphi_ns: float, gate_time_ns: float) -> float:
     """The component of Pauli error caused by decoherence.
 
     Args:
-        T1_ns: T1 time in nanoseconds.
-        Tphi_ns: Tphi time in nanoseconds.
+        t1_ns: T1 time in nanoseconds.
+        tphi_ns: Tphi time in nanoseconds.
         gate_time_ns: Duration in nanoseconds of the gate affected by this error.
+
+    Returns:
+        Calculated Pauli error resulting from decoherence.
     """
-    Gamma2 = (1 / (2 * T1_ns)) + 1 / Tphi_ns
+    Gamma2 = (1 / (2 * t1_ns)) + 1 / tphi_ns
 
-    exp1 = np.exp(-gate_time_ns / T1_ns)
+    exp1 = np.exp(-gate_time_ns / t1_ns)
     exp2 = np.exp(-gate_time_ns * Gamma2)
     px = 0.25 * (1 - exp1)
     py = px