From cbccf2dfc7d5ada536d8beef7975881772d73a05 Mon Sep 17 00:00:00 2001
From: Shuli Shu <08cnbj@gmail.com>
Date: Tue, 17 Sep 2024 17:42:09 +0000
Subject: [PATCH] apply python layer comments

---
 .../lightning_tensor/_tensornet.py             | 18 ++++++++++--------
 .../lightning_tensor/lightning_tensor.py       |  5 ++---
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/pennylane_lightning/lightning_tensor/_tensornet.py b/pennylane_lightning/lightning_tensor/_tensornet.py
index 5b4a444e09..c91c10570b 100644
--- a/pennylane_lightning/lightning_tensor/_tensornet.py
+++ b/pennylane_lightning/lightning_tensor/_tensornet.py
@@ -111,16 +111,16 @@ def gate_matrix_decompose(gate_ops_matrix, wires, c_dtype):
 
     # Convert the MPOs to the correct order for the cutensornet backend
     mpos = []
-    for i in range(len(MPOs)):
-        if i == 0:
+    for index, MPO in enumerate(MPOs):
+        if index == 0:
             # [ket, bra, bond](0, 1, 2) -> [ket, bond, bra](0, 2, 1) -> Fortran order or reverse indices(1, 2, 0) to match the order requirement of cutensornet backend.
-            mpos.append(np.transpose(MPOs[i], axes=(1, 2, 0)))
-        elif i == len(MPOs) - 1:
+            mpos.append(np.transpose(MPO, axes=(1, 2, 0)))
+        elif index == len(MPOs) - 1:
             # [bond, ket, bra](0, 1, 2) -> Fortran order or reverse indices(2, 1, 0) to match the order requirement of cutensornet backend.
-            mpos.append(np.transpose(MPOs[i], axes=(2, 1, 0)))
+            mpos.append(np.transpose(MPO, axes=(2, 1, 0)))
         else:
             # [bondL, ket, bra, bondR](0, 1, 2, 3) -> [bondL, ket, bondR, bra](0, 1, 3, 2) -> Fortran order or reverse indices(2, 3, 1, 0) to match the requirement of cutensornet backend.
-            mpos.append(np.transpose(MPOs[i], axes=(2, 3, 1, 0)))
+            mpos.append(np.transpose(MPO, axes=(2, 3, 1, 0)))
 
     return mpos, sorted_wires
 
@@ -365,12 +365,14 @@ def _apply_lightning(self, operations):
                     method = getattr(tensornet, "applyMatrix")
                     try:
                         method(qml.matrix(operation), wires, False)
-                    except AttributeError:
+                    except AttributeError:  # pragma: no cover
+                        # To support older versions of PL
                         method(operation.matrix(), wires, False)
             else:
                 try:
                     gate_ops_matrix = qml.matrix(operation)
-                except AttributeError:
+                except AttributeError:  # pragma: no cover
+                    # To support older versions of PL
                     gate_ops_matrix = operation.matrix()
 
                 self._apply_MPO(gate_ops_matrix, wires)
diff --git a/pennylane_lightning/lightning_tensor/lightning_tensor.py b/pennylane_lightning/lightning_tensor/lightning_tensor.py
index 60406aadc8..ff53d41ede 100644
--- a/pennylane_lightning/lightning_tensor/lightning_tensor.py
+++ b/pennylane_lightning/lightning_tensor/lightning_tensor.py
@@ -168,9 +168,8 @@
 
 def stopping_condition(op: Operator) -> bool:
     """A function that determines whether or not an operation is supported by the ``mps`` method of ``lightning.tensor``."""
-    # These thresholds are adapted from `lightning_base.py`
-    # To avoid building matrices beyond the given thresholds.
-    # This should reduce runtime overheads for larger systems.
+    # TODOs: These thresholds are from ``lightning.qubit`` and should be adjuested based on the benchmarking tests for the MPS
+    #  simulator (against both max_mps_bond_dim and number of qubits).
     if isinstance(op, qml.QFT):
         return len(op.wires) < 10
     if isinstance(op, qml.GroverOperator):