Changelog¶

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Effort-based versioning.

Unreleased ¶

robust_phase_estimation: replaced epsilon with n_repetitions, removed sign_E0, added an rng argument for deterministic sampling, added a t0 argument setting the base evolution time, and changed the trotter_order default from 2 to 1. The estimated phase is now E0 * t0, so the energy is recovered as theta / t0. The returned list now has length n_repetitions (no leading placeholder).
run_hadamard_test / rpe_get_hadamard_output: replaced seed with an rng (numpy.random.Generator) argument.
build_hadamard_test_circuit / run_hadamard_test: renamed the theta argument to phase_gate_angle.
rpe_get_hadamard_output: renamed the m argument to evolution_time. It now takes the evolution time itself instead of the exponent m; callers passing m positionally must pass 2**m to keep the previous behaviour.
Renamed rpe_distance to angular_distance; it is now vectorized.
rpe_update_theta: signature changed to (phi_m, theta_ref, m), now returning a single angle.
optuna dependency moved from core dependency to recommended.
draw_layered_circuit / draw_layered_expval: replaced the list_names argument with three keyword-only arguments state_label, labels_1qubit and labels_2qubit. A label list shorter than the circuit depth now raises ValueError instead of failing with an IndexError while drawing.

rpe_distance (renamed to angular_distance).
hyperoptimization example and all QAOA-related code: examples/hyperoptimization.py, src/qpe_toolbox/circuit/qaoa.py and tests/test_qaoa.py. This removes brute_force_maxcut, compute_qaoa_contraction_costs and study_optimization_time_costs from qpe_toolbox.circuit.
two_qubit_rand_layer: the reverse argument. It only changed the order in which overlapping gates were applied, and never the control direction its documentation claimed.

draw_layered_expval: two-qubit layer labels were indexed in the opposite direction to single-qubit ones, so the two label lists disagreed on which layer they were naming.
draw_layered_circuit / draw_layered_expval: unlabelled diagrams drew [''] next to every qubit instead of nothing.

Initial public release of qpe-toolbox.
circuit module: quimb circuit construction, parametrized circuits, QAOA, gate counting, serialization, and plotting.
hamiltonian module: Hamiltonian class, spin models, pyscf interface for molecular chemistry, fermionic encodings via openfermion.
estimation module: textbook and robust QPE variants, LCU walk operators, block encoding, QFT, Hadamard test.
tensor module: MPS/MPO utilities beyond what quimb provides natively.
Sphinx documentation deployed to GitHub Pages.
Full test suite with ≥ 70 % branch coverage.
CI/CD workflows for testing and PyPI publishing.