Skip to content

Release v0.30.0
Compare
Choose a tag to compare
@mlxd mlxd released this 01 May 17:47
· 232 commits to master since this release
v0.30.0
680734a

New features since last release

  • Add MCMC sampler.
    (#384)

  • Serialize PennyLane's arithmetic operators when they are used as observables
    that are expressed in the Pauli basis.
    (#424)

Breaking changes

  • Lightning now works with the new return types specification that is now default in PennyLane.
    See the PennyLane qml.enable_return documentation for more information on this change.
    (#427)

Instead of creating potentially ragged numpy array, devices and QNode's now return an object of the same type as that
returned by the quantum function.

>>> dev = qml.device('lightning.qubit', wires=1)
>>> @qml.qnode(dev, diff_method="adjoint")
... def circuit(x):
...     qml.RX(x, wires=0)
...     return qml.expval(qml.PauliY(0)), qml.expval(qml.PauliZ(0))
>>> x = qml.numpy.array(0.5)
>>> circuit(qml.numpy.array(0.5))
(array(-0.47942554), array(0.87758256))

Interfaces like Jax or Torch handle tuple outputs without issues:

>>> jax.jacobian(circuit)(jax.numpy.array(0.5))
(Array(-0.87758255, dtype=float32, weak_type=True),
Array(-0.47942555, dtype=float32, weak_type=True))

Autograd cannot differentiate an output tuple, so results must be converted to an array before
use with qml.jacobian:

>>> qml.jacobian(lambda y: qml.numpy.array(circuit(y)))(x)
array([-0.87758256, -0.47942554])

Alternatively, the quantum function itself can return a numpy array of measurements:

>>> dev = qml.device('lightning.qubit', wires=1)
>>> @qml.qnode(dev, diff_method="adjoint")
>>> def circuit2(x):
...     qml.RX(x, wires=0)
...     return np.array([qml.expval(qml.PauliY(0)), qml.expval(qml.PauliZ(0))])
>>> qml.jacobian(circuit2)(np.array(0.5))
array([-0.87758256, -0.47942554])

Improvements

  • Remove deprecated set-output commands from workflow files.
    (#437)

  • Lightning wheels are now checked with twine check post-creation for PyPI compatibility.
    (#430)

  • Lightning has been made compatible with the change in return types specification.
    (#427)

  • Lightning is compatible with clang-tidy version 16.
    (#429)

Contributors

This release contains contributions from (in alphabetical order):

Christina Lee, Vincent Michaud-Rioux, Lee James O'Riordan, Chae-Yeun Park, Matthew Silverman

Assets 2
Loading