Pennylane-lightning

Improvements

* Introduces requirements-dev.txt and improves dockerfile. [(330)](https://github.com/PennyLaneAI/pennylane-lightning/pull/330)

* Support `expval` for a Hamiltonian. [(333)](https://github.com/PennyLaneAI/pennylane-lightning/pull/333)

* Implements caching for Kokkos installation. [(316)](https://github.com/PennyLaneAI/pennylane-lightning/pull/316)

* Supports measurements of operator arithmetic classes such as `Sum`, `Prod`,
and `SProd` by deferring handling of them to `DefaultQubit`. [(349)](https://github.com/PennyLaneAI/pennylane-lightning/pull/349)


qml.qnode(qml.device('lightning.qubit', wires=2))
def circuit():
obs = qml.s_prod(2.1, qml.PauliZ(0)) + qml.op_sum(qml.PauliX(0), qml.PauliZ(1))
return qml.expval(obs)


Bug fixes

* Test updates to reflect new measurement error messages. [(334)](https://github.com/PennyLaneAI/pennylane-lightning/pull/334)

* Updates to the release tagger to fix incompatibilities with RTD. [(344)](https://github.com/PennyLaneAI/pennylane-lightning/pull/344)

* Update cancel-workflow-action and bot credentials. [(345)](https://github.com/PennyLaneAI/pennylane-lightning/pull/345)

Contributors

This release contains contributions from (in alphabetical order):

Amintor Dusko, Christina Lee, Lee J. O'Riordan, Chae-Yeun Park

Bug fixes

* Ensure build type for CMake in all compilers and operational systems.
[(341)](https://github.com/PennyLaneAI/pennylane-lightning/pull/341)

Contributor

Amintor Dusko

New features since last release

Breaking changes

* We explicitly disable support for PennyLane's parameter broadcasting. [317](https://github.com/PennyLaneAI/pennylane-lightning/pull/317)

* We explicitly remove support for PennyLane's `Sum`, `SProd` and `Prod`
as observables. [(326)](https://github.com/PennyLaneAI/pennylane-lightning/pull/326)

Improvements

* CI builders use a reduced set of resources and redundant tests for PRs. [(319)](https://github.com/PennyLaneAI/pennylane-lightning/pull/319)

* Parallelize wheel-builds where applicable. [(314)](https://github.com/PennyLaneAI/pennylane-lightning/pull/314)

* AVX2/512 kernels are now available on Linux/MacOS with x86-64 architecture. [(313)](https://github.com/PennyLaneAI/pennylane-lightning/pull/313)

Documentation

* Updated ReadTheDocs runner version from Ubuntu 20.04 to 22.04 [(327)](https://github.com/PennyLaneAI/pennylane-lightning/pull/327)

Bug fixes

* Test updates to reflect new additions to PennyLane. [(318)](https://github.com/PennyLaneAI/pennylane-lightning/pull/318)

Contributors

This release contains contributions from (in alphabetical order):

Amintor Dusko, Christina Lee, Rashid N H M, Lee J. O'Riordan, Chae-Yeun Park

New features since last release

* Add `SingleExcitation` and `DoubleExcitation` qchem gates and generators. [(289)](https://github.com/PennyLaneAI/pennylane-lightning/pull/289)

* Add a new dispatch mechanism for future kernels. [(291)](https://github.com/PennyLaneAI/pennylane-lightning/pull/291)

* Add `IsingXY` gate operation. [(303)](https://github.com/PennyLaneAI/pennylane-lightning/pull/303)

* Support `qml.state()` in vjp and Hamiltonian in adjoint jacobian. [(294)](https://github.com/PennyLaneAI/pennylane-lightning/pull/294)

Breaking changes

* Codebase is now moving to C++20. The default compiler for Linux is now GCC10. [(295)](https://github.com/PennyLaneAI/pennylane-lightning/pull/295)

* Minimum macOS version is changed to 10.15 (Catalina). [(295)](https://github.com/PennyLaneAI/pennylane-lightning/pull/295)

Improvements

* Split matrix operations, refactor dispatch mechanisms, and add a benchmark suite. [(274)](https://github.com/PennyLaneAI/pennylane-lightning/pull/274)

* Add native support for the calculation of sparse Hamiltonians' expectation values. Sparse operations are offloaded to [Kokkos](https://github.com/kokkos/kokkos) and [Kokkos-Kernels](https://github.com/kokkos/kokkos-kernels). [(#283)](https://github.com/PennyLaneAI/pennylane-lightning/pull/283)

* Device `lightning.qubit` now accepts a datatype for a statevector. [(290)](https://github.com/PennyLaneAI/pennylane-lightning/pull/290)

python
dev1 = qml.device('lightning.qubit', wires=4, c_dtype=np.complex64) for single precision
dev2 = qml.device('lightning.qubit', wires=4, c_dtype=np.complex128) for double precision


Documentation

* Use the centralized [Xanadu Sphinx Theme](https://github.com/XanaduAI/xanadu-sphinx-theme) to style the Sphinx documentation. [(#287)](https://github.com/PennyLaneAI/pennylane-lightning/pull/287)

Bug fixes

* Fix the issue with using available `clang-format` version in format. [(288)](https://github.com/PennyLaneAI/pennylane-lightning/pull/288)

* Fix a bug in the generator of `DoubleExcitationPlus`. [(298)](https://github.com/PennyLaneAI/pennylane-lightning/pull/298)

Contributors

This release contains contributions from (in alphabetical order):
Mikhail Andrenkov, Ali Asadi, Amintor Dusko, Lee James O'Riordan, Chae-Yeun Park, and Shuli Shu

New features since last release

* Add `generate_samples()` to lightning. [(247)](https://github.com/PennyLaneAI/pennylane-lightning/pull/247)

* Add Lightning GBenchmark Suite. [(249)](https://github.com/PennyLaneAI/pennylane-lightning/pull/249)

* Support runtime and compile information. [(253)](https://github.com/PennyLaneAI/pennylane-lightning/pull/253)

Improvements

* Add `ENABLE_BLAS` build to CI checks. [(249)](https://github.com/PennyLaneAI/pennylane-lightning/pull/249)

* Add more `clang-tidy` checks and kernel tests. [(253)](https://github.com/PennyLaneAI/pennylane-lightning/pull/253)

* Add C++ code coverage to CI. [(265)](https://github.com/PennyLaneAI/pennylane-lightning/pull/265)

* Skip over identity operations in `"lightning.qubit"`. [(268)](https://github.com/PennyLaneAI/pennylane-lightning/pull/268)

Bug fixes

* Update tests to remove `JacobianTape`. [(260)](https://github.com/PennyLaneAI/pennylane-lightning/pull/260)

* Fix tests for MSVC. [(264)](https://github.com/PennyLaneAI/pennylane-lightning/pull/264)

* Fix `include <cpuid.h>` for PPC and AArch64 in Linux. [(266)](https://github.com/PennyLaneAI/pennylane-lightning/pull/266)

* Remove deprecated tape execution methods. [(270)](https://github.com/PennyLaneAI/pennylane-lightning/pull/270)

* Update `qml.probs` in `test_measures.py`. [(280)](https://github.com/PennyLaneAI/pennylane-lightning/pull/280)

Contributors

This release contains contributions from (in alphabetical order):
Ali Asadi, Chae-Yeun Park, Lee James O'Riordan, and Trevor Vincent

Bug fixes

* Ensure `qml.Identity` kernel is registered to C++ dispatcher. [(275)](https://github.com/PennyLaneAI/pennylane-lightning/pull/275)