Parameter assignment of QuantumCircuitdoes not update the data attribute when inplace=True #13478
Description
Environment
- Qiskit version: 1.2.4
- Python version: 3.10
- Operating system: Mac OS Sequoia
What is happening?
When writing the following:
import numpy as np
from qiskit.circuit.library import TwoLocal
num_qubits = 6
n_layers = 4
qc = TwoLocal(num_qubits, "rx", "cx", entanglement=[[(0, 1), (2, 3), (4, 5)], [(1, 2), (3, 4)]], reps=n_layers, flatten=True, skip_unentangled_qubits=True, skip_final_rotation_layer=True)
qc.assign_parameters(rotation_angles, inplace=True)
print(qc.data)we get:
[CircuitInstruction(operation=Instruction(name='rx', num_qubits=1, num_clbits=0, params=[ParameterVectorElement(θ[0])]), qubits=(Qubit(QuantumRegister(6, 'q'), 0),), clbits=()), CircuitInstruction(operation=Instruction(name='rx', num_qubits=1, num_clbits=0, params=[ParameterVectorElement(θ[1])]), ...]Meaning that instructions still store the reference to the original Parameters, which should have been replaced by the values.
This behavior does not appear when doing
qc=qc.assign_parameters(rotation_angles, inplace=False)where in this case the binding is clearly visible on the instructions
How can we reproduce the issue?
import numpy as np
from qiskit.circuit.library import TwoLocal
num_qubits = 6
n_layers = 4
qc = TwoLocal(num_qubits, "rx", "cx", entanglement=[[(0, 1), (2, 3), (4, 5)], [(1, 2), (3, 4)]], reps=n_layers, flatten=True, skip_unentangled_qubits=True, skip_final_rotation_layer=True)
rotation_angles = np.random.random(qc.num_parameters)
qc.assign_parameters(rotation_angles, inplace=True)
print(qc.data)What should happen?
Instructions should be binded with the numeric values in both cases. One should therefore take care of the inplace=True case to match the other case.
Any suggestions?
No response