Attribute Error in Reverse QGT

[Gopal-Dahale]

Environment

• Qiskit Algorithms version: 0.3.0
• Python version: 3.10.0
• Operating system: Ubuntu 22.04.5 LTS

What is happening?

When using ReverseQGT, we get the following error:

AttributeError: 'QuantumCircuit' object has no attribute '_parameter_table'

How can we reproduce the issue?

from qiskit.circuit.library import TwoLocal
from qiskit_algorithms.gradients import ReverseQGT
import numpy as np

n_qubits = 1
qc = TwoLocal(
    n_qubits,
    ["rx"],
    ["cx"],
    "linear",
    reps=1,
    skip_final_rotation_layer=True,
    flatten=True,
)
params = np.random.rand(qc.num_parameters)
grad = ReverseQGT()
grad.run([qc], [params]).result()

What should happen?

It should not throw this error.

Any suggestions?

We need to update the ReverseQGT with the supported attributes of QuantumCircuit for the latest qiskit version.

[woodsp-ibm]

This was brought up as an issue in

• Nightly test against Qiskit main failing #181

and was fixed by

• Update gradient logic for Qiskit Rust circuit data implementation #188

This code has not yet been released - I note you refer to the released version 0.3.0 and indeed that has that issue, but it has already been corrected in the codebase here, just not released yet. As such this has already been fixed so I am closing this,