QuTiP 5.0.0

[Simon Cross]

Greetings,

QuTiP 5.0.0 has been released!

QuTiP 5 is a redesign of many of the core components of QuTiP (Qobj, QobjEvo, solvers) to make them more consistent and more flexible.

Qobj may now be stored in either sparse or dense representations, and the two may be mixed sensibly as needed. QobjEvo is now used consistently throughout QuTiP, and the implementation has been substantially cleaned up. A new Coefficient class is used to represent the time-dependent factors inside QobjEvo.

The solvers have been rewritten to work well with the new data layer and the concept of Integrators which solve ODEs has been introduced. In future, new data layers may provide their own Integrators specialized to their representation of the underlying data.

Much of the user-facing API of QuTiP remains familiar, but there have had to be many small breaking changes. If we can make changes to easy migrating code from QuTiP 4 to QuTiP 5, please let us know.

We have written a draft migration guide that is available in Google Colab: https://colab.research.google.com/drive/18TcuHNQifYSHdGey7otK8IPDB1YbDZpW?usp=sharing.  It provides short recipes for common pitfalls. We plan to keep updating it. Suggestions for additions welcome.

QuTiP 5 was a massive effort by many contributors. Please take a moment to look through the list of contributors https://qutip.readthedocs.io/en/qutip-5.0.x/changelog.html#contributor.

Full release notes: https://github.com/qutip/qutip/releases/tag/v5.0.0
PyPI: https://pypi.org/project/qutip/5.0.0/
Conda-forge: https://anaconda.org/conda-forge/qutip

Documentation: https://qutip.readthedocs.io/en/qutip-5.0.x/

Migration guide: https://colab.research.google.com/drive/18TcuHNQifYSHdGey7otK8IPDB1YbDZpW?usp=sharing

Please give it a whirl and report any issues encountered at
https://github.com/qutip/qutip/issues

Yours sincerely,

Simon Cross