{"id":24489,"library":"qiskit-algorithms","title":"Qiskit Algorithms","description":"A library of quantum computing algorithms for variational quantum eigensolvers (VQE), quantum phase estimation (QPE), Grover's search, amplitude estimation, and more. Current version 0.4.0 supports Qiskit 2.x and PrimitivesV2. Release cadence is approximately every 2-4 months.","status":"active","version":"0.4.0","language":"python","source_language":"en","source_url":"https://github.com/qiskit-community/qiskit-algorithms","tags":["quantum computing","algorithms","vqe","grover","qiskit","quantum","primitives"],"install":[{"cmd":"pip install qiskit-algorithms","lang":"bash","label":"stable"}],"dependencies":[{"reason":"Core Qiskit dependency for quantum circuit construction, transpilation, and primitives.","package":"qiskit","optional":false},{"reason":"Used for classical optimizers (e.g., SLSQP) in VQE.","package":"scipy","optional":true},{"reason":"Numerical computations backend.","package":"numpy","optional":false}],"imports":[{"note":"In Qiskit 0.25+ algorithms moved to standalone package. Importing from qiskit.algorithms is deprecated and will break in Qiskit 1.0+.","wrong":"from qiskit.algorithms import VQE","symbol":"VQE","correct":"from qiskit_algorithms import VQE"},{"note":"Same as above; all algorithm classes moved to qiskit_algorithms.","wrong":"from qiskit.algorithms import QAOA","symbol":"QAOA","correct":"from qiskit_algorithms import QAOA"},{"note":"","wrong":null,"symbol":"Grover","correct":"from qiskit_algorithms import Grover"},{"note":"","wrong":null,"symbol":"AmplitudeEstimation","correct":"from qiskit_algorithms import AmplitudeEstimation"}],"quickstart":{"code":"from qiskit import QuantumCircuit\nfrom qiskit.primitives import StatevectorSampler\nfrom qiskit_algorithms import Grover\nfrom qiskit_algorithms.amplitude_amplifiers import GroverOperator\n\n# Define a simple oracle for |11>\noracle = QuantumCircuit(2)\noracle.cz(0, 1)\n\n# Grover operator\ngrover_op = GroverOperator(oracle)\n\n# Grover instance\nsampler = StatevectorSampler()\ngrover = Grover(sampler=sampler)\n\n# Run Grover's algorithm\nresult = grover.amplify(grover_op)\nprint(\"Top measurement:\", result.top_measurement)","lang":"python","description":"A minimal example of Grover's search with the standalone qiskit-algorithms package."},"warnings":[{"fix":"Replace `from qiskit.algorithms import ...` with `from qiskit_algorithms import ...` and ensure qiskit-algorithms is installed.","message":"Post-Qiskit 1.0, `qiskit.algorithms` is removed entirely. Use `qiskit-algorithms` standalone package.","severity":"gotcha","affected_versions":"qiskit >=1.0, qiskit-algorithms <0.3.0 (no support); use qiskit-algorithms >=0.3.0"},{"fix":"Update primitive references: `from qiskit.primitives import StatevectorSampler` instead of `from qiskit.primitives import Sampler`.","message":"PrimitivesV2 support in 0.4.0 changes the API: algorithms now accept sampler/estimator V2 instances (e.g., StatevectorSampler) instead of V1 (e.g., Sampler).","severity":"breaking","affected_versions":"qiskit-algorithms 0.4.0+"},{"fix":"Install qiskit-algorithms and change imports to `qiskit_algorithms`.","message":"`qiskit.algorithms` module (in qiskit-terra) is deprecated since Qiskit 0.25 and removed in Qiskit 1.0.","severity":"deprecated","affected_versions":"qiskit 0.25 - 0.46, qiskit 1.0+"}],"env_vars":null,"last_verified":"2026-05-01T00:00:00.000Z","next_check":"2026-07-30T00:00:00.000Z","problems":[{"fix":"pip install qiskit-algorithms, then change imports to `from qiskit_algorithms import ...`","cause":"Qiskit 1.0+ removed the algorithms module. Use the standalone package.","error":"ModuleNotFoundError: No module named 'qiskit.algorithms'"},{"fix":"Use VQE(estimator, ansatz, optimizer) with required positional arguments: VQE(estimator, ansatz, optimizer). Check docs for correct signature.","cause":"In qiskit-algorithms 0.3+, the VQE constructor changed: use `estimator` and `optimizer` keyword, not `ansatz` directly.","error":"TypeError: VQE.__init__() got an unexpected keyword argument 'ansatz'"},{"fix":"Use `from qiskit_algorithms.minimum_eigensolvers import NumPyMinimumEigensolver`.","cause":"Some algorithms moved to submodules in later versions.","error":"AttributeError: module 'qiskit_algorithms' has no attribute 'NumPyMinimumEigensolver'"}],"ecosystem":"pypi","meta_description":null,"install_score":null,"install_tag":null,"quickstart_score":null,"quickstart_tag":null}