M. Useful Quantum Software

The toolbox, laptop-first (all free; all local unless noted). SDKs: Qiskit (this book's default; IBM ecosystem), Cirq (Google), PennyLane (Xanadu — quantum-ML oriented), Braket SDK (AWS). Simulators: qiskit-aer (your workhorse), stim (Clifford/QEC — thousands of qubits; the Part X engine), Qiskit's stabilizer/MPS methods, quimb / ITensor (tensor networks, Ch. 64.2), qsim (Google's fast statevector). QEC toolchain: stim (circuit-level noise + sampling), PyMatching (MWPM decoder), pymatching/panqec/fault-painter adjacent tools. Compilers/research: PyZX (ZX-calculus — Ch. 45.4), Boulder Opal-adjacent open tools (control), OpenQASM 3 tooling. Chemistry: Qiskit Nature, PySCF (classical integrals — 48.6's pipeline), OpenFermion. Hardware access: IBM Quantum platform (free open tier — Ch. 64.7), AWS Braket / Azure Quantum (paid, credits). Reference/resource estimation: Azure Quantum Resource Estimator (Ch. 79.4). Benchmarks: QASMBench, BenchPress corpora (Ch. 46.8). Selection rule: default to Qiskit+stim+numpy; add per specialization (Ch. 74's list).