Upgrade Guide¶

This document describes breaking changes and how to upgrade. For a complete list of changes including minor and patch releases, please refer to the changelog.

3.6.0 ¶

This release brings extended support for multi-controlled gates that was introduced in https://github.com/munich-quantum-toolkit/core/pull/1380 to the ZX-calculus checker.

This release also updates the minimum required mqt-core version to v3.6.0 as well as the nanobind version to v2.12.0.

3.5.0 ¶

To comply with established guidelines for attribute names, mqt.qcec.pyqcec.StateType.random_1Q_basis has been renamed to random_1q_basis.

This release also updates the minimum required mqt-core version to v3.4.1 as well as the nanobind version to v2.11.0.

3.4.0 ¶

Python wheels¶

This release contains two changes to the distributed wheels.

First, we have removed all wheels for Python 3.13t. Free-threading Python was introduced as an experimental feature in Python 3.13. It became stable in Python 3.14.

Second, for Python 3.12+, we are now providing Stable ABI wheels instead of separate version-specific wheels. This was enabled by migrating our Python bindings from pybind11 to nanobind.

Both of these changes were made in the interest of conserving PyPI space and reducing CI/CD build times. The full list of wheels now reads:

3.10
3.11
3.12+ Stable ABI
3.14t

Starting with this release, MQT QCEC no longer supports Python 3.9. This is in line with the scheduled end of life of the version. As a result, MQT QCEC is no longer tested under Python 3.9 and no longer ships Python 3.9 wheels.

3.2.0 ¶

Testing previous versions of the mqt-qcec package built via uv sync or simple (uv) pip install . generally failed due to binary incompatibility of the mqt-core compiled extension packages and the mqt-qcec one. This required building mqt-core from source and without build isolation to get a working local setup. By using the latest pybind11 release (v3), the binary compatibility between extension modules compiled under different circumstances (such as different compilers) has been greatly increased. As such, it is no longer necessary to build mqt-core from source and without build isolation when locally working on mqt-qcec. A simple uv sync is enough to successfully run pytest.

The ApplicationScheme, EquivalenceCriterion, and StateType enums are now exposed via pybind11’s new py::native_enum, which makes them compatible with Python’s enum.Enum class (PEP 435). As a result, the enums can no longer be initialized using a string. Instead of ApplicationScheme("sequential") or "sequential", use ApplicationScheme.sequential.

Finally, the minimum required C++ version has been raised from C++17 to C++20. The default compilers of our test systems support all relevant features of the standard.

3.1.0 ¶

Even tough this is not a breaking change, it is worth mentioning to developers of MQT QCEC that all Python code (except tests) has been moved to the top-level python directory. Furthermore, the C++ code for the Python bindings has been moved to the top-level bindings directory.

3.0.0 ¶

This major release introduces several breaking changes, including the removal of deprecated features and the introduction of new APIs. The following paragraphs describe the most important changes and how to adapt your code accordingly. We intend to provide a more comprehensive migration guide for future releases.

The major change in this major release is the move to the MQT Core Python package. This move allows us to make qiskit a fully optional dependency and entirely rely on the MQT Core IR for representing circuits. Additionally, the mqt-core Python package now ships all its C++ libraries as shared libraries so that these need not be fetched or built as part of the build process. This was tricky to achieve cross-platform, and you can find some more backstory in the corresponding PR. We expect this integration to mature over the next few releases. If you encounter any issues, please let us know.

Some internals of QCEC have been streamlined and refactored to improve the overall code quality and maintainability. Most notably, counterexamples are now returned as decision diagrams instead of dense arrays. This was made possible by the move to the MQT Core Python package, which now also exposes the underlying DD package to Python. The returned DDs have a get_vector() method that can be used to convert them to a dense array if needed.

MQT Core itself dropped support for several parsers in v3.0.0, including the .real, .qc, .tfc, and GRCS parsers. The .real parser lives on as part of the MQT SyReC project. All others have been removed without replacement. Consequently, these input formats are no longer supported in MQT QCEC.

MQT QCEC has moved to the munich-quantum-toolkit GitHub organization under https://github.com/munich-quantum-toolkit/qcec. While most links should be automatically redirected, please update any links in your code to point to the new location. All links in the documentation have been updated accordingly.

MQT QCEC now requires CMake 3.24 or higher. Most modern operating systems should have this version available in their package manager. Alternatively, CMake can be conveniently installed from PyPI using the cmake package.