Error when import qiskit-algorithms

[EduMolinero]

Environment

• Qiskit version:
  qiskit 2.0.1
  qiskit-algorithms 0.3.1
• Python version:
  Python 3.12.9
• Operating system:
  macos sequoia 15.4.1

What is happening?

When I try to import anything from qiskit-algorithms I get the following error:

---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
Cell In[4], line 1
----> 1 from qiskit_nature.second_q.mappers import JordanWignerMapper
      2 mapper = JordanWignerMapper()

File ~/anaconda3/envs/quantum/lib/python3.12/site-packages/qiskit_nature/__init__.py:53
      1 # This code is part of a Qiskit project.
      2 #
      3 # (C) Copyright IBM 2018, 2023.
   (...)     10 # copyright notice, and modified files need to carry a notice indicating
     11 # that they have been altered from the originals.
     12 r"""
     13 =============================================
     14 Qiskit Nature module (:mod:`qiskit_nature`)
   (...)     50 
     51 """
---> 53 from qiskit_algorithms.list_or_dict import ListOrDict as ListOrDictType
     55 from .exceptions import QiskitNatureError, UnsupportMethodError
     56 from .logging import logging

File ~/anaconda3/envs/quantum/lib/python3.12/site-packages/qiskit_algorithms/__init__.py:254
    252 from .algorithm_job import AlgorithmJob
    253 from .algorithm_result import AlgorithmResult
--> 254 from .variational_algorithm import VariationalAlgorithm, VariationalResult
    255 from .amplitude_amplifiers import Grover, GroverResult, AmplificationProblem, AmplitudeAmplifier
    256 from .amplitude_estimators import (
    257     AmplitudeEstimator,
    258     AmplitudeEstimatorResult,
   (...)    267     EstimationProblem,
    268 )

File ~/anaconda3/envs/quantum/lib/python3.12/site-packages/qiskit_algorithms/variational_algorithm.py:36
     33 from qiskit.circuit import QuantumCircuit
     35 from .algorithm_result import AlgorithmResult
---> 36 from .optimizers import OptimizerResult
     39 class VariationalAlgorithm(ABC):
     40     """The Variational Algorithm Base Class."""

File ~/anaconda3/envs/quantum/lib/python3.12/site-packages/qiskit_algorithms/optimizers/__init__.py:139
    137 from .p_bfgs import P_BFGS
    138 from .powell import POWELL
--> 139 from .qnspsa import QNSPSA
    140 from .scipy_optimizer import SciPyOptimizer
    141 from .slsqp import SLSQP

File ~/anaconda3/envs/quantum/lib/python3.12/site-packages/qiskit_algorithms/optimizers/qnspsa.py:23
     20 import numpy as np
     21 from qiskit.circuit import QuantumCircuit
---> 23 from qiskit.primitives import BaseSampler
     24 from qiskit_algorithms.state_fidelities import ComputeUncompute
     26 from .spsa import SPSA, CALLBACK, TERMINATIONCHECKER, _batch_evaluate

ImportError: cannot import name 'BaseSampler' from 'qiskit.primitives' (/Users/user/anaconda3/envs/quantum/lib/python3.12/site-packages/qiskit/primitives/__init__.py)

How can we reproduce the issue?

The error arises from the import directly

from qiskit_algorithms import *

What should happen?

It should import the class without any kind of errors. From the documentation of qiskit the BaseSamplerhas been splitted into two different object BaseSamplerV1and BaseSamplerV2, so I think this is the cause of the error.

Any suggestions?

I've tried to change the import of BaseSampler into either BaseSamplerV1 or BaseSamplerV2 in the qiskit_algorithms/optimizers/qnspsa.pyfile, but I get the following error:

---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
Cell In[2], line 1
----> 1 from qiskit_nature.second_q.mappers import JordanWignerMapper
      2 mapper = JordanWignerMapper()

File ~/anaconda3/envs/quantum/lib/python3.12/site-packages/qiskit_nature/__init__.py:53
      1 # This code is part of a Qiskit project.
      2 #
      3 # (C) Copyright IBM 2018, 2023.
   (...)     10 # copyright notice, and modified files need to carry a notice indicating
     11 # that they have been altered from the originals.
     12 r"""
     13 =============================================
     14 Qiskit Nature module (:mod:`qiskit_nature`)
   (...)     50 
     51 """
---> 53 from qiskit_algorithms.list_or_dict import ListOrDict as ListOrDictType
     55 from .exceptions import QiskitNatureError, UnsupportMethodError
     56 from .logging import logging

File ~/anaconda3/envs/quantum/lib/python3.12/site-packages/qiskit_algorithms/__init__.py:254
    252 from .algorithm_job import AlgorithmJob
    253 from .algorithm_result import AlgorithmResult
--> 254 from .variational_algorithm import VariationalAlgorithm, VariationalResult
    255 from .amplitude_amplifiers import Grover, GroverResult, AmplificationProblem, AmplitudeAmplifier
    256 from .amplitude_estimators import (
    257     AmplitudeEstimator,
    258     AmplitudeEstimatorResult,
   (...)    267     EstimationProblem,
    268 )

File ~/anaconda3/envs/quantum/lib/python3.12/site-packages/qiskit_algorithms/variational_algorithm.py:36
     33 from qiskit.circuit import QuantumCircuit
     35 from .algorithm_result import AlgorithmResult
---> 36 from .optimizers import OptimizerResult
     39 class VariationalAlgorithm(ABC):
     40     """The Variational Algorithm Base Class."""

File ~/anaconda3/envs/quantum/lib/python3.12/site-packages/qiskit_algorithms/optimizers/__init__.py:139
    137 from .p_bfgs import P_BFGS
    138 from .powell import POWELL
--> 139 from .qnspsa import QNSPSA
    140 from .scipy_optimizer import SciPyOptimizer
    141 from .slsqp import SLSQP

File ~/anaconda3/envs/quantum/lib/python3.12/site-packages/qiskit_algorithms/optimizers/qnspsa.py:24
     21 from qiskit.circuit import QuantumCircuit
     23 from qiskit.primitives import BaseSamplerV1
---> 24 from qiskit_algorithms.state_fidelities import ComputeUncompute
     26 from .spsa import SPSA, CALLBACK, TERMINATIONCHECKER, _batch_evaluate
     28 # the function to compute the fidelity

File ~/anaconda3/envs/quantum/lib/python3.12/site-packages/qiskit_algorithms/state_fidelities/__init__.py:40
      1 # This code is part of a Qiskit project.
      2 #
      3 # (C) Copyright IBM 2022, 2023.
   (...)     10 # copyright notice, and modified files need to carry a notice indicating
     11 # that they have been altered from the originals.
     12 """
     13 State Fidelities (:mod:`qiskit_algorithms.state_fidelities`)
     14 ============================================================
   (...)     37 
     38 """
---> 40 from .base_state_fidelity import BaseStateFidelity
     41 from .compute_uncompute import ComputeUncompute
     42 from .state_fidelity_result import StateFidelityResult

File ~/anaconda3/envs/quantum/lib/python3.12/site-packages/qiskit_algorithms/state_fidelities/base_state_fidelity.py:24
     22 from qiskit import QuantumCircuit
     23 from qiskit.circuit import ParameterVector
---> 24 from qiskit.primitives.utils import _circuit_key
     26 from ..algorithm_job import AlgorithmJob
     29 class BaseStateFidelity(ABC):

ImportError: cannot import name '_circuit_key' from 'qiskit.primitives.utils' (/Users/user/anaconda3/envs/quantum/lib/python3.12/site-packages/qiskit/primitives/utils.py)

I've also tried to install everything from scratch using either pip or conda in new enviroments but the problem remains.

[woodsp-ibm]

Qiskit Algorithms (as well as the application modules, such as Qiskit Nature) do not support Qiskit 2.0. There is an issue here #224 for algorithms and similar in the application repos. For now you need to install a Qiskit version < 2.0 such as the latest 1.4 version 1.4.3, You can do this using pip install qiskit==1.4.3