Extended support for different V2 transpilers from different backends. (backport #879) (#882)

* Added checks for different transpiler types (#879)

(cherry picked from commit e1859dd)

* Update constraints.txt

---------

Co-authored-by: M. Emre Sahin <[email protected]>
Co-authored-by: Edoardo Altamura <[email protected]>

Author: 3 people

qiskit_machine_learning/neural_networks/estimator_qnn.py

@@ -183,7 +183,10 @@ def __init__(
                 self.num_virtual_qubits = circuit.num_qubits
             else:
                 circuit = pass_manager.run(circuit)
-                self.num_virtual_qubits = circuit.layout._input_qubit_count
+                if hasattr(circuit.layout, "_input_qubit_count"):
+                    self.num_virtual_qubits = circuit.layout._input_qubit_count
+                else:
+                    self.num_virtual_qubits = circuit.num_qubits
 
         self._org_circuit = circuit
 

qiskit_machine_learning/neural_networks/sampler_qnn.py

@@ -209,7 +209,10 @@ def __init__(
                 self.num_virtual_qubits = circuit.num_qubits
             else:
                 circuit = pass_manager.run(circuit)
-                self.num_virtual_qubits = circuit.layout._input_qubit_count
+                if hasattr(circuit.layout, "_input_qubit_count"):
+                    self.num_virtual_qubits = circuit.layout._input_qubit_count
+                else:
+                    self.num_virtual_qubits = circuit.num_qubits
 
         self._org_circuit = circuit