----------------------
Breaking Changes:
- Major module re-org of superoperator tools into `operator_tools` also moved `random_operators` to the operator tools module. Added type checking in random operators, added new module to check plain old operators are unitary etc (gh-150, 140, 164).
- Remove symmetrization functionality from `observable_estimation` in favor of pyquil functionality (gh-194).
- Methods in `fitting` renamed to be less ambiguous `decay_constant_param_decay` -> `decay_time_param_decay` and
`fit_decay_constant_param_decay` -> `fit_decay_time_param_decay`. Correspondingly, the fit parameter was renamed
`decay_constant` -> `decay_time`(gh-175)
- `generate_cz_phase_ramsey_experiment` was made plural, consistent with rest of `qubit_spectroscopy` (gh-175)
- `acquire_cz_phase_ramsey_data` removed in favor of `estimate_observables` and all other specific `acquire_*` methods
in `qubit_spectroscopy.py` were removed in favor of `acquire_qubit_spectroscopy_data` (gh-175)
- argument order standardized, which changed the api of `generate_exhaustive_process_dfe_experiment`,
`generate_exhaustive_state_dfe_experiment`, `generate_monte_carlo_state_dfe_experiment`,
`generate_monte_carlo_process_dfe_experiment`, `robust_phase_estimate`,
and positional arg name of `acquire_dfe_data` (gh-182)
Improvements and Changes:
- Fixed the years in this Change log file 2018 -> 2019
- Added linear inversion process tomography (gh-142)
- Changed qubit tensor factor ordering of state tomography estimates to match that of process tomography, e.g.
tomographizing the plus eigenstate of `X0 * Z1` and passing in `qubits = [0,1]` will yield the state
estimate corresponding to `|+0> = (1, 0, 1, 0)/sqrt(2)` rather than `|0+>` (gh-142)
- Improved the `superoperator_tools` notebook and the `random_operators` notebook (gh-98)
- Improvements to Ripple carry adder notebook, added tests for non parametric bit string
prep program in utils (gh-98)
- Added the ability to project a Choi matrix to the closest unitary (gh-159, 157)
- Reduced local test run time from 11min to 5min (gh-160)
- Major changes and improvements to all notebooks (gh-148, 149, 153, 154, 155, 156, 165, 167, 172, 182(see 183))
- Speedup the tests (gh-158, 161)
- Complete overhaul/addition of documentation in docs folder (gh-170, 174)
- Github PR and bug report templates added (gh-177, 182)
- `merge_disjoint_experiments` and `get_results_by_qubit_groups` added to `observable_estimation.py` to facilitate
running experiments 'in parallel' on a QPU and analyzing the results separately (gh-182)
- various `do_*` methods added that wrap various experiments into a single method with sensible defaults (gh-182)
- examples notebooks moved to docs/ directory to be rendered within documentation (gh-182)
- tqdm progress bars added to most data acquisition methods (gh-182)
Bugfixes:
- Dagger is now implemented in pyquil as a gate-level modifier, but this doesn't play well with noise models on the QVM
so a stop-gap was put into basic_compile to hand compile the dagger modifier (gh-169)
- Compiler sometimes failed to find connected subgraphs of qubits (gh-188)
- QPU cannot handle integer parameters (gh-188)