mirror of https://github.com/Qiskit/qiskit.git
19 lines
850 B
YAML
19 lines
850 B
YAML
---
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upgrade:
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- |
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The :class:`~qiskit.circuit.library.QFT` class in the
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:mod:`qiskit.circuit.library` module now computes the Fourier transform
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using a little-endian representation of tensors, i.e. the state
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:math:`|1\rangle` maps to :math:`|0\rangle - |1\rangle + |2\rangle - ..`
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assuming the computational basis correspond to little-endian bit ordering
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of the integers. :math:`|0\rangle = |000\rangle, |1\rangle = |001\rangle`,
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etc. This was done to make it more consistent with the rest of Qiskit,
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which uses a little-endian convention for bit order. If you were depending
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on the previous bit order you can use the
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:meth:`~qiskit.circuit.library.QFT.reverse_bits` method to revert to the
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previous behavior. For example::
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from qiskit.circuit.library import QFT
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qft = QFT(5).reverse_bits()
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