Updating descriptions and replacing 'tns' with 'tn'

doc/releases/changelog-dev.md

@@ -4,7 +4,11 @@
 
 <h3>New features since last release</h3>
 
-* The `default.tensor` device is introduced to perform tensor network simulation of a quantum circuit.
+* The `default.tensor` device now supports the `tn` method to simulate quantum circuits using exact tensor networks.
+  [(#5786)](https://github.com/PennyLaneAI/pennylane/pull/5786)
+
+* The `default.tensor` device is introduced to perform tensor network simulation of a quantum circuit using the `mps`
+  (Matrix Product State) method.
   [(#5699)](https://github.com/PennyLaneAI/pennylane/pull/5699)
 
 <h3>Improvements 🛠</h3>

pennylane/devices/default_tensor.py

@@ -123,7 +123,7 @@
 )
 # The set of supported observables.
 
-_methods = frozenset({"mps", "tns"})
+_methods = frozenset({"mps", "tn"})
 # The set of supported methods.
 
 
@@ -160,7 +160,7 @@ class DefaultTensor(Device):
         wires (int, Iterable[Number, str]): Number of wires present on the device, or iterable that
             contains unique labels for the wires as numbers (i.e., ``[-1, 0, 2]``) or strings
             (``['aux_wire', 'q1', 'q2']``).
-        method (str): Supported method. Currently, the supported methods are 'mps' (Matrix Product State) and 'tns' (Exact Tensor Network).
+        method (str): Supported method. Currently, the supported methods are 'mps' (Matrix Product State) and 'tn' (Exact Tensor Network).
         dtype (type): Data type for the tensor representation. Must be one of ``np.complex64`` or ``np.complex128``.
         **kwargs: keyword arguments for the device, passed to the ``quimb`` backend.
 
@@ -172,8 +172,8 @@ class DefaultTensor(Device):
         contract (str): The contraction method for applying gates in the MPS method. It can be either ``auto-mps`` or ``nonlocal``.
             ``nonlocal`` turns each gate into a Matrix Product Operator (MPO) and applies it directly to the MPS,
             while ``auto-mps`` swaps nonlocal qubits in 2-qubit gates to be next to each other before applying the gate,
-            then swaps them back. Default is ``auto-mps``. TODO: change this
-        # TODO: add options for TNS
+            then swaps them back. Default is ``auto-mps``. TODO: update description with new choices
+        # TODO: add kwargs for TN
 
     **Example:**
 
@@ -272,7 +272,7 @@ def __init__(
 
         if not accepted_methods(method):
             raise ValueError(
-                f"Unsupported method: {method}. Supported methods are 'mps' (Matrix Product State) and 'tns' (Exact Tensor Network)."
+                f"Unsupported method: {method}. Supported methods are 'mps' (Matrix Product State) and 'tn' (Exact Tensor Network)."
             )
 
         if dtype not in [np.complex64, np.complex128]:
@@ -285,7 +285,7 @@ def __init__(
         self._method = method
         self._dtype = dtype
 
-        # options both for MPS and TNS
+        # options both for MPS and TN
         # TODO: add options
 
         # options for MPS
@@ -340,10 +340,10 @@ def _initialize_quimb_circuit(self, wires: qml.wires.Wires) -> None:
                 cutoff=self._cutoff,
             )
 
-        elif self.method == "tns":
+        elif self.method == "tn":
             self._quimb_circuit = qtn.Circuit(
-                psi0=self._initial_tns(wires),
-                # TODO: add options for TNS
+                psi0=self._initial_tn(wires),
+                # TODO: add options for TN
             )
 
         else:
@@ -367,7 +367,7 @@ def _initial_mps(self, wires: qml.wires.Wires) -> "qtn.MatrixProductState":
             tags=[str(l) for l in wires.labels] if wires else None,
         )
 
-    def _initial_tns(self, wires: qml.wires.Wires) -> "qtn.TensorNetwork":
+    def _initial_tn(self, wires: qml.wires.Wires) -> "qtn.TensorNetwork":
         r"""
         Return an initial tensor network state to :math:`\ket{0}`.
 
@@ -714,3 +714,4 @@ def execute_and_compute_vjp(
         raise NotImplementedError(
             "The computation of vector-Jacobian product has yet to be implemented for the default.tensor device."
         )
+

tests/devices/default_tensor/test_default_tensor.py

@@ -162,7 +162,7 @@ def test_wires_runtime_error():
 @pytest.mark.parametrize("max_bond_dim", [None, 10])
 @pytest.mark.parametrize("cutoff", [1e-16, 1e-12])
 @pytest.mark.parametrize("contract", ["auto-mps", "nonlocal"])
-@pytest.mark.parametrize("method", ["mps", "tns"])
+@pytest.mark.parametrize("method", ["mps", "tn"])
 def test_kwargs(method, max_bond_dim, cutoff, contract):
     """Test the class initialization with different arguments and returned properties."""
 
@@ -191,7 +191,7 @@ def test_invalid_kwarg():
         qml.device("default.tensor", wires=0, fake_arg=None)
 
 
-@pytest.mark.parametrize("method", ["mps", "tns"])
+@pytest.mark.parametrize("method", ["mps", "tn"])
 def test_method(method):
     """Test the device method."""
     assert qml.device("default.tensor", method=method).method == method
@@ -216,7 +216,7 @@ def test_ivalid_data_type():
         qml.device("default.tensor", wires=0, dtype=float)
 
 
-@pytest.mark.parametrize("method", ["mps", "tns"])
+@pytest.mark.parametrize("method", ["mps", "tn"])
 class TestSupportedGatesAndObservables:
     """Test that the DefaultTensor device supports all gates and observables that it claims to support."""
 
@@ -320,7 +320,7 @@ def test_execute_and_compute_vjp(self):
             dev.execute_and_compute_vjp(circuits=None, cotangents=None)
 
 
-@pytest.mark.parametrize("method", ["mps", "tns"])
+@pytest.mark.parametrize("method", ["mps", "tn"])
 class TestJaxSupport:
     """Test the JAX support for the DefaultTensor device."""
 

tests/devices/default_tensor/test_tensor_expval.py

@@ -35,9 +35,9 @@
 @pytest.fixture(
     params=[
         (np.complex64, "mps"),
-        (np.complex64, "tns"),
+        (np.complex64, "tn"),
         (np.complex128, "mps"),
-        (np.complex128, "tns"),
+        (np.complex128, "tn"),
     ]
 )
 def dev(request):
@@ -110,7 +110,7 @@ def test_multi_wire_identity_expectation(self, theta, phi, dev):
         assert np.allclose(1.0, result, tol)
 
     @pytest.mark.parametrize("wires", [([0, 1]), (["a", 1]), (["b", "a"]), ([-1, 2.5])])
-    @pytest.mark.parametrize("method", ["mps", "tns"])
+    @pytest.mark.parametrize("method", ["mps", "tn"])
     def test_custom_wires(self, theta, phi, wires, method):
         """Tests custom wires."""
         dev = qml.device("default.tensor", wires=wires, method=method)
@@ -361,7 +361,7 @@ def test_PauliZ_hadamard_PauliY(self, theta, phi, varphi, dev):
 
 
 @pytest.mark.parametrize("theta, phi", list(zip(THETA, PHI)))
-@pytest.mark.parametrize("method", ["mps", "tns"])
+@pytest.mark.parametrize("method", ["mps", "tn"])
 def test_multi_qubit_gates(theta, phi, method):
     """Tests a simple circuit with multi-qubit gates."""
 

tests/devices/default_tensor/test_tensor_var.py

@@ -34,9 +34,9 @@
 @pytest.fixture(
     params=[
         (np.complex64, "mps"),
-        (np.complex64, "tns"),
+        (np.complex64, "tn"),
         (np.complex128, "mps"),
-        (np.complex128, "tns"),
+        (np.complex128, "tn"),
     ]
 )
 def dev(request):
@@ -107,7 +107,7 @@ def test_multi_wire_identity_variance(self, theta, phi, dev):
         assert np.allclose(0.0, result, atol=tol, rtol=0)
 
     @pytest.mark.parametrize("wires", [([0, 1]), (["a", 1]), (["b", "a"]), ([-1, 2.5])])
-    @pytest.mark.parametrize("method", ["mps", "tns"])
+    @pytest.mark.parametrize("method", ["mps", "tn"])
     def test_custom_wires(self, theta, phi, wires, method):
         """Tests custom wires."""
         device = qml.device("default.tensor", wires=wires, method=method)
@@ -371,7 +371,7 @@ def test_PauliZ_hadamard_PauliY(self, theta, phi, varphi, dev):
 # in the tape computation with `default.qubit`, that we use as reference.
 @pytest.mark.usefixtures("new_opmath_only")
 @pytest.mark.parametrize("theta, phi", list(zip(THETA, PHI)))
-@pytest.mark.parametrize("method", ["mps", "tns"])
+@pytest.mark.parametrize("method", ["mps", "tn"])
 def test_multi_qubit_gates(theta, phi, method):
     """Tests a simple circuit with multi-qubit gates."""