qiskit/releasenotes/notes/0.15/transformationpass_property...

16 lines
825 B
YAML

---
upgrade:
- |
In previous releases a :class:`~qiskit.transpiler.PassManager`
did not allow ``TransformationPass`` classes to modify the
:class:`~qiskit.transpiler.PropertySet`. This restriction has been lifted
so a ``TransformationPass`` class now has read and write access to both
the :class:`~qiskit.transpiler.PropertySet` and
:class:`~qiskit.transpiler.DAGCircuit` during
:meth:`~qiskit.transpiler.PassManager.run`. This change was made to
more efficiently facilitate ``TransformationPass`` classes that have an
internal state which may be necessary for later passes in the
:class:`~qiskit.transpiler.PassManager`. Without this change a second
redundant ``AnalysisPass`` would have been necessary to recreate the
internal state, which could add significant overhead.