fixing parametrization flag and updating relevant test scripts

examples/quimb_intro/test.py

@@ -24,21 +24,23 @@ hamiltonian = hamiltonians.SymbolicHamiltonian(form)
 
 # define circuit
 def build_circuit(nqubits, nlayers):
-    """Construct a Qibo parametric quantum circuit."""
+    """Construct a more complex Qibo parametric quantum circuit without CNOT gates."""
     circ = Circuit(nqubits)
-    for _ in range(nlayers):
+    for layer in range(nlayers):
         for q in range(nqubits):
             circ.add(gates.RY(q=q, theta=0.))
             circ.add(gates.RZ(q=q, theta=0.))
-        [circ.add(gates.CZ(q % nqubits, (q + 1) % nqubits)) for q in range(nqubits)]
+            circ.add(gates.RX(q=q, theta=0.))
+        # Add controlled rotations and SWAPs for entanglement
+        for q in range(nqubits - 1):
+            circ.add(gates.CNOT(q, q + 1))
+            circ.add(gates.SWAP(q, q + 1))
     circ.add(gates.M(*range(nqubits)))
     return circ
 
-nqubits = 4
+nqubits = 6
 circuit = build_circuit(nqubits=nqubits, nlayers=3)
 
-quimb_circuit = quimb_backend._qibo_circuit_to_quimb(circuit)
-
 def f(params):
     circuit.set_parameters(params)
     return quimb_backend.expectation(

src/qibotn/backends/quimb.py

@@ -376,45 +376,6 @@ class QuimbBackend(QibotnBackend, NumpyBackend):
 
         return A_new, B_new, C_new
 
-    # def _qibo_circuit_to_quimb(self, qibo_circ, quimb_circuit_type=qtn.Circuit, **circuit_kwargs):
-    #     """
-    #     Convert a Qibo Circuit to a Quimb Circuit.
-
-    #     Parameters
-    #     ----------
-    #     qibo_circ : qibo.models.circuit.Circuit
-    #         The circuit to convert.
-    #     quimb_circuit_type : type
-    #         The Quimb circuit class to use (Circuit, CircuitMPS, etc).
-    #     circuit_kwargs : dict
-    #         Extra arguments to pass to the Quimb circuit constructor.
-
-    #     Returns
-    #     -------
-    #     circ : quimb.tensor.circuit.Circuit
-    #         The converted circuit.
-    #     """
-    #     nqubits = qibo_circ.nqubits
-    #     quimb_gates = []
-    #     circ = quimb_circuit_type(nqubits, **circuit_kwargs)
-
-    #     for gate in qibo_circ.queue:
-    #         gname = getattr(gate, "name", None)
-    #         qname = GATE_MAP.get(gname, None)
-    #         if qname is None:
-    #             continue  # skip measurements and unknown gates
-
-    #         # Handle parametrized gates (Qibo: .parameters, Quimb: expects flat tuple)
-    #         params = getattr(gate, "parameters", ())
-    #         qubits = getattr(gate, "qubits", ())
-
-    #         # Quimb expects (*params, *qubits)
-    #         gate_spec = (qname,) + tuple(params) + tuple(qubits)
-    #         quimb_gates.append(gate_spec)
-
-    #     circ.apply_gates(quimb_gates)
-    #     return circ
-
     def _qibo_circuit_to_quimb(self, qibo_circ, quimb_circuit_type=qtn.Circuit, **circuit_kwargs):
         """
         Convert a Qibo Circuit to a Quimb Circuit.
@@ -446,8 +407,11 @@ class QuimbBackend(QibotnBackend, NumpyBackend):
             qubits = getattr(gate, "qubits", ())
             
             # Check if the gate is parametrized
-            is_parametrized = isinstance(gate, ParametrizedGate)
+            is_parametrized = (
-            
+                isinstance(gate, ParametrizedGate)
+                and getattr(gate, "trainable", True)
+            )
+            # import pdb; pdb.set_trace()
             if is_parametrized:
                 circ.apply_gate(
                     qname,