mirror of https://github.com/Qiskit/qiskit.git
54 lines
2.9 KiB
YAML
54 lines
2.9 KiB
YAML
---
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features:
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A new a new 2-qubit gate, :class:`~qiskit.circuit.library.ECRGate`,
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the echo cross-resonance (ECR), has been added to the
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:mod:`qiskit.circuit.library` module along with a corresponding method,
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:meth:`~qiskit.circuit.QuantumCircuit.ecr` for the
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:class:`~qiskit.circuit.QuantumCircuit` class. The ECR gate is two
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:math:`CR(\frac{π,4})` pulses with an
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:class:`~qiskit.circuit.library.XGate` between them for the echo. This gate
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is locally equivalent to a :class:`~qiskit.circuit.library.CXGate` (can
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convert to a CNOT with local pre- or post-rotation). It is the native gate
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on current IBM hardware and compiling to it allows the pre-/post-rotations
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to be merged into the rest of the circuit.
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A new kwarg ``approximation_degree`` has been added to the
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:func:`~qiskit.compiler.transpile` function for enabling
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approximate compilation. Valid values range from 0 to 1, and higher
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means less approximation. This is a heuristic dial
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to experiment with circuit approximations. The concrete interpretation
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of this number is left to each pass, which may use it to perform
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some approximate version of the pass. Specific examples include
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unitary synthesis or translators to discrete gate sets.
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If a pass does not support this option, it implies exact transformation.
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Two new transpiler passess, :class:`~qiskit.transpiler.GateDirection` and
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class:`qiskit.transpiler.CheckGateDirection`, were added to the
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:mod:`qiskit.transpiler.passes` module. These new passes are intended to
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be more general replacements for
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:class:`~qiskit.transpiler.passes.CXDirection` and
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:class:`~qiskit.transpiler.passes.CheckCXDirection` (which are both now
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deprecated, see the deprecation notes for more details) that perform the
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same function but work with other gates beside just
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:class:`~qiskit.circuit.library.CXGate`.
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deprecations:
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The :class:`~qiskit.transpiler.passes.CXDirection` transpiler pass in the
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:mod:`qiskit.transpiler.passes` module has been deprecated and will be
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removed in a future release. Instead the
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:class:`~qiskit.transpiler.GateDirection` should be used. It behaves
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identically to the :class:`~qiskit.transpiler.passes.CXDirection` except
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that it now also supports transforming a circuit with
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:class:`~qiskit.circuit.library.ECRGate` gates in addition to
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:class:`~qiskit.circuit.library.CXGate` gates.
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The :class:`~qiskit.transpiler.passes.CheckCXDirection` transpiler pass in
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the :mod:`qiskit.transpiler.passes` module has been deprecated and will be
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removed in a future release. Instead the
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:class:`~qiskit.transpiler.CheckGateDirection` pass should be used.
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It behaves identically to the
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:class:`~qiskit.transpiler.passes.CheckCXDirection` except
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that it now also supports checking the direction of all 2-qubit gates, not
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just :class:`~qiskit.circuit.library.CXGate` gates.
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