qiskit/releasenotes/notes/1.3/deprecate-unit-duration-48b...

46 lines
2.7 KiB
YAML

---
features_visualization:
- |
The :func:`.timeline_drawer` visualization function has a new argument
``target``, used to specify a :class:`.Target` object for the
visualization. By default the function used the
:attr:`.Instruction.duration` to get the duration of a given instruction,
but specifying the target will leverage the timing details inside the
target instead.
deprecations_circuits:
- |
The :attr:`.QuantumCircuit.unit` and :attr:`.QuantumCircuit.duration`
attributes have been deprecated and will be removed in Qiskit 2.0.0. These
attributes were used to track the estimated duration and unit of that
duration to execute on the circuit. However, the values of these attributes
were always limited, as they would only be properly populated if the
transpiler were run with the correct settings. The duration was also only a
guess based on the longest path on the sum of the duration of
:class:`.DAGCircuit` and wouldn't ever correctly account for control flow
or conditionals in the circuit.
- |
The :attr:`.DAGCircuit.unit` and :attr:`.DAGCircuit.duration`
attributes have been deprecated and will be removed in Qiskit 2.0.0. These
attributes were used to track the estimated duration and unit of that
duration to execute on the circuit. However, the values of these attributes
were always limited, as they would only be properly populated if the
transpiler were run with the correct settings. The duration was also only a
guess based on the longest path on the sum of the duration of
:class:`.DAGCircuit` and wouldn't ever correctly account for control flow
or conditionals in the circuit.
- |
The :attr:`.Instruction.duration` and :attr:`.Instruction.unit` attributes
have been deprecated and will be removed in Qiskit 2.0.0. This includes
setting the ``unit`` or ``duration`` arguments for any :class:`qiskit.circuit.Instruction`
or subclass. These attributes were used to attach a custom execution
duration and unit for that duration to an individual instruction. However,
the source of truth of the duration of a gate is the :class:`.BackendV2`
:class:`.Target` which contains the duration for each instruction supported
on the backend. The duration of an instruction is not something that's
typically user adjustable and is an immutable property of the backend. If
you were previously using this capability to experiment with different
durations for gates you can mutate the
:attr:`.InstructionProperties.duration` field in a given :class:`.Target` to
set a custom duration for an instruction on a backend (the unit is always in
seconds in the :class:`.Target`).