Release 0.40.0-dev

New features since last release

Add Exact Tensor Network C++ backend to lightning.tensor. (#977)
Add native N-controlled generators and adjoint support to lightning.gpu's single-GPU backend. (#970)
Add a Catalyst-specific wrapping class for Lightning-Qubit. (#960) (#999)
Add native N-controlled gate/matrix operations and adjoint support to lightning.kokkos. (#950)
Add native N-controlled gates support to lightning.gpu's single-GPU backend. (#938)

Breaking changes

Handling for the legacy operator arithmetic (the Hamiltonian and Tensor classes in PennyLane) is removed. (#994) (#997)
Removed all instances of qml.QubitStateVector. (#985)

Improvements

Add CUDA dependencies to Lightning GPU and Lightning Tensor Python wheels. (#1025)
Replace the dummy_tensor_update method with the cutensornetStateCaptureMPSAPI to ensure that further gates apply is allowed after the cutensornetStateCompute call. (#1028)
Add unit test for measurement with shots for Lightning Tensor with tn method. (#1027)
Update the python layer UI of Lightning Tensor. (#1022)
Catalyst device interfaces support dynamic shots, and no longer parses the device init op's attribute dictionary for a static shots literal. (#1017)
Update the logic for enabling grad_on_execution during device execution. (#1016)
Reduce flaky test and increase test shots count. (#1015)
Add Exact Tensor Network cpp binding. (#1014)
Reverse Lightning Qubit generators vector insertion order. (#1009)
Update Kokkos version support to 4.5. (#1007)
Enable N-controlled gate and matrix support to lightning.gpu simulator for Catalyst. (#1005)
Generalize seeding mechanism for all measurements. (#1003)
lightning.qubit, lightning.gpu, and lightning.kokkos now define the eval_jaxpr method for integration with the experimental capture project. (#1002)
Update Kokkos version support to 4.4.1 and enable Lightning-Kokkos[CUDA] C++ tests on CI. (#1000)
Add C++ unit tests for Exact Tensor Network backends. (#998)
Add native BLAS support to the C++ layer via dynamic scipy-openblas32 loading. (#995)
Update installation instruction for Lightning-GPU-MPI to explicitly ask users to add path/to/libmpi.so to the LD_LIBRARY_PATH. Update the runtime error message to ensure users know how to fix. (#993)
The TOML files for the devices are updated to use the new schema for declaring device capabilities. (#988)
Optimize lightning.tensor by adding direct MPS sites data set with qml.MPSPrep. (#983)
Unify excitation gates memory layout to row-major for both LGPU and LT. (#959)
Update the lightning.kokkos CUDA backend for compatibility with Catalyst. (#942)

Documentation

Add the exact tensor network to the Lightning-Tensor docs. (#1021)
Update Lightning-Tensor installation docs and usage suggestions. (#979)

Bug fixes

Add RTLD_NODELETE flag to dlopen in order to mitigate the segfault issues for arm64-macos Catalyst support. (#1030)
Set rpath with @loader_path instead of $ORIGIN for macOS. (#1029)
Update CUDA version to 12.4 for GPU tests on CI. (#1023)
Fix Lightning Kokkos [[maybe_unused]] and exp2 errors with hipcc. (#1018)
Pin jax[cpu]==0.4.28 for compatibility with PennyLane and Catalyst. (#1019)
Fix Lightning Kokkos editable mode path. (#1010)
Fix the missing ninja in Linux AARCH64 wheels recipe. (#1007)
Fix version switch condition the GPU workflow tests for LGPU and LKokkos. (#1006)
Fix issue with lightning.gpu Rot operation with adjoint. (#1004)
Fix the Lightning-Kokkos[CUDA] C++ API cudaFree segfaults in applyMatrix. (#1000)
Fix issue with adjoint-jacobian of adjoint ops. (#996)
Fix the upload-pypi token issues for Linux and MacOS (x86_64 & AARCH64) wheels. (#989)
Fix Pennylane dependency branch (v0.39_rc0 to master). (#984)
Fix PTM stable latest. Removing FIXME patch for v0.39. (#982)

Contributors

This release contains contributions from (in alphabetical order):

Ali Asadi, Astral Cai, Amintor Dusko, Christina Lee, Joseph Lee, Anton Naim Ibrahim, Luis Alfredo Nuñez Meneses, Andrija Paurevic, Shuli Shu, Raul Torres, Haochen Paul Wang

Release 0.39.0

New features since last release

Add support for out-of-order qml.probs in lightning.gpu. (#941)
Add mid-circuit measurements support to lightning.gpu's single-GPU backend. (#931)
Integrate Lightning-GPU with Catalyst so that hybrid programs can be seamlessly QJIT-compiled and executed on this device following pip install pennylane-lightning-gpu. (#928)
Add qml.Projector observable support via diagonalization to Lightning-GPU. (#894)
Add 1-target wire controlled gate support to lightning.tensor. Note that cutensornet only supports 1-target wire controlled gate as of v24.08. A controlled gate with more than 1 target wire should be converted to dense matrix. (#880)
Build and upload Lightning-Tensor wheels (x86_64, AARCH64) to PyPI. (#862) (#905)
Add Matrix Product Operator (MPO) for all gates support to lightning.tensor. Note current C++ implementation only works for MPO sites data provided by users. (#859)
Add shots measurement support to lightning.tensor. (#852)
Lightning-GPU and Lightning-Kokkos migrated to the new device API. (#853) (#810)

Breaking changes

Update MacOS wheel build to 13.0 for X86_64 and ARM due to the deprecation of MacOS-12 CI runners. (#969)
Deprecate initSV() and add resetStateVector() from the C++ API Lightning-GPU. This is to remove the reset_state additional call in the Python layer. (#933)
Deprecate PI gates implementation in Lightning-Qubit. The PI gates were the first implementation of gate kernels in lightning.qubit using pre-computed indices, prior to the development of LM (less memory) and AVX kernels. This deprecation is in favour of reducing compilation time and ensuring that Lightning-Qubit only relies on LM kernels in the dynamic dispatcher across all platforms. (#925)
Remove PowerPC wheel build recipe for Lightning-Qubit. (#902)
Update MacOS wheel builds to require Monterey (12.0) or greater for x86_64 and ARM. This was required to update Pybind11 to the latest release (2.13.5) for enabling Numpy 2.0 support in Lightning. (#901)
Remove support for Python 3.9 for all Lightning simulators. (#891)

Improvements

Update the lightning.tensor Python layer unit tests, as lightning.tensor cannot be cleaned up like other state-vector devices because the data is attached to the graph. It is recommended to use one device per circuit for lightning.tensor. (#971)
Add joint check for the N-controlled wires support in lightning.qubit. (#949)
Optimize GlobalPhase and C(GlobalPhase) gate implementation in lightning.gpu. (#946)
Add missing liblightning_kokkos_catalyst.so when building Lightning-Kokkos in editable installation. (#945)
Optimize the cartesian product to reduce the amount of memory necessary to set the StatePrep in Lightning-Tensor. (#943)
Update the qml.probs data-return in Lightning-GPU C++ API to align with other state-vector devices. (#941)
Add zero-state initialization to both StateVectorCudaManaged and StateVectorCudaMPI constructors to remove the reset_state in the Python layer ctor and refactor setBasisState(state, wires) in the C++ API. (#933)
Add setStateVector(state, wire) support to the Lightning-GPU C++ API. (#930)
The generate_samples methods of lightning.qubit and lightning.kokkos can now take in a seed number to make the generated samples deterministic. This can be useful when, among other things, fixing flaky tests in CI. (#927)
Remove dynamic decomposition rules for all Lightning devices. (#926)
Always decompose qml.QFT in all Lightning devices. (#924)
Uniform Python format to adhere PennyLane style. (#924)
Add the ci:use-gpu-runner GitHub label to lightning.kokkos GPU Testing CIs. (#916)
Update the test suite to remove deprecated code. (#912)
Merge lightning.gpu and lightning.tensor GPU tests in single Python and C++ CIs controlled by the ci:use-gpu-runner label. (#911)
Skip the compilation of Lightning simulators and development requirements to boost the build of public docs up to 5x. (#904)
Build Lightning wheels in Release mode to reduce the binary sizes. (#903)
Update Pybind11 to 2.13.5. (#901)
Migrate wheels artifacts to v4. (#893)
Update GitHub actions in response to a high-severity vulnerability. (#887)
Optimize and simplify controlled kernels in Lightning-Qubit. (#882)
Optimize gate cache recording for Lightning-Tensor C++ API. (#879)
Unify Lightning-Kokkos and Lightning-Qubit devices under a Lightning-Base abstracted class. (#876)
Smarter defaults for the split_obs argument in the serializer. The serializer splits linear combinations into chunks instead of all their terms. (#873)
Prefer tomlkit over toml for building Lightning wheels, and choose tomli and tomllib over toml when installing the package. (#857)
Lightning-Kokkos gains native support for the PauliRot gate. (#855)

Documentation

Update Lightning-Tensor installation docs and usage suggestions. (#971) (#972)
Update README.rst installation instructions for lightning.gpu and lightning.tensor. (#957)
Update lightning.tensor documentation to include all the new features added since pull request #756. The new features are: 1. Finite-shot measurements; 2. Expval-base quantities; 3. Support for qml.state() and qml.stateprep(); 4. Support for all gates support via Matrix Product Operator (MPO). (#909)

Bug fixes

Fix Lightning Kokkos test_device for kokkos_args fail for MacOS due to np.complex256 (#974)
Fix PTM stable-latest related to default.qubit.legacy and the latest flag usage. (#961) (#966)
Fix build failure for Lightning-Kokkos editable installation on MacOS due to liblightning_kokkos_catalyst.so copy and liblightning_kokkos_catalyst.so not copied to correct build path for editable installation. (#947) (#968)
Add concept restriction to ensure ConstMult inline function only hit with arithmetic-values times complex values. Fixes build failures with the test suite when enabling OpenMP, and disabling BLAS and Python under clang. (#936)
Bug fix for applyMatrix in Lightning-Tensor. Matrix operator data is not stored in the cuGateCache object to support TensorProd obs with multiple Hermitian obs. (#932)
Bug fix for _pauli_word of QuantumScriptSerializer. _pauli_word can process PauliWord object: I. (#919)
Bug fix for analytic qml.probs in the Lightning-Tensor C++ API. (#906)

Contributors

This release contains contributions from (in alphabetical order):

Ali Asadi, Amintor Dusko, Diego Guala, Joseph Lee, Luis Alfredo Nuñez Meneses, Vincent Michaud-Rioux, Lee J. O'Riordan, Mudit Pandey, Shuli Shu, Haochen Paul Wang

Release 0.38.0

New features since last release

Add qml.StatePrep() and qml.QubitStateVector() support to lightning.tensor. (#849)
Add analytic qml.probs() measurement support to lightning.tensor. (#830)
Add qml.state() measurement support to lightning.tensor. (#827)
Add Lightning-GPU Linux (AArch64 + GraceHopper) wheels to PyPI. (#815)
Add var support to lightning.tensor. Note that var support is added via obs**2 and this implementation scales as O(num_obs**2). (#804)

Breaking changes

Update python packaging to follow PEP 517/518/621/660 standards. (#832)
Add getData() in the lightning.tensor C++ backend. Users are responsible for ensuring sufficient host memory is allocated for the full state vector. (#827)
Remove NDpermuter.hpp which is no longer required. (#795)
Remove temporary steps from the CI, such as downgrading Scipy to <1.14 and installing Kokkos v4.2 for lightning-version == 'stable'. (#792)
Do not run GPU tests and Docker workflows on release. (#788)
Update python packaging to follow PEP 517/518/621/660 standards. (#832)

Improvements

Updated calls of size_t to std::size_t everywhere. (#816)
Update Lightning tests to support the generalization of basis state preparation. (#864)
Add SetState and SetBasisState to Lightning-KokkosSimulator. (#861)
Remove use of the deprecated Operator.expand in favour of Operator.decomposition. (#846)
The setBasisState and setStateVector methods of StateVectorLQubit and StateVectorKokkos are overloaded to support PennyLane-like parameters. (#843)
Move setBasisState, setStateVector and resetStateVector from StateVectorLQubitManaged to StateVectorLQubit. (#841)
Update generate_samples in Lightning-Kokkos and Lightning-GPU to support qml.measurements.Shots type instances. (#839)
Add a Catalyst-specific wrapping class for Lightning Kokkos. (#837) (#770)
Lightning-Qubit natively supports the PauliRot gate. (#834)
Multiple calls to the append_mps_final_state() API is allowed in lightning.tensor. (#830)
Add initial_state_prep option to Catalyst TOML file. (#826)
ENABLE_LAPACK is OFF by default for all Lightning backends. (#825)
Update ctrl_decomp_zyz tests with len(control_wires) > 1. (#821)
Update the Catalyst-specific wrapping class for Lightning Kokkos to track Catalyst's new support for MCM seeding. (#819)
Replace size_t by std::size_t everywhere. (#816)
Shot batching is made more efficient by executing all the shots in one go on Lightning-Qubit. (#814)
Lightning-Qubit calls generate_samples(wires) on a minimal subset of wires when executing in finite-shot mode. (#813)
Update LightingQubit.preprocess to work with changes to preprocessing for mid-circuit measurements. (#812)
Avoid unnecessary memory reset in Lightning-Qubit's state vector class constructor. (#811)
Add generate_samples(wires) support in Lightning-Qubit, which samples faster for a subset of wires. (#809)
Optimize the OpenMP parallelization of Lightning-Qubit's probs for all number of targets. (#807)
Optimize probs(wires) of Lightning-Kokkos using various kernels. Which kernel is to be used depends on the device, number of qubits and number of target wires. (#802)
Add GPU device compute capability check for Lightning-Tensor. (#803)
Refactor CUDA utils Python bindings to a separate module. (#801)
Parallelize Lightning-Qubit probs with OpenMP when using the -DLQ_ENABLE_KERNEL_OMP=1 CMake argument. (#800)
Implement probs(wires) using a bit-shift implementation akin to the gate kernels in Lightning-Qubit. (#795)
Enable setting the PennyLane version when invoking, for example, make docker-build version=master pl_version=master. (#791)

Documentation

The installation instructions for all lightning plugins have been improved. (#858) (#851)
Updated the README and added citation format for Lightning arXiv preprint. (#818)

Bug fixes

Point to the right Lightning root folder independently from the invocation location, when configuring the project. (#874)
Update dependencies and build command options following changes in the build system. (#863)
Replace structured bindings by variables in GateImplementationsLM.hpp. (#856)
Remove wrong -m when calling setup.py. (#854)
Fix plugin-test-matrix CI/CD workflows. (#850)
Set the immutable parameter value as false for the cutensornetStateApplyTensorOperator to allow the following cutensornetStateUpdateTensorOperator call. (#845)
Fix cuQuantum SDK path pass-though in CMake. (#831)
Fix CUDA sync issues on AArch64 + GraceHopper. (#823)
Check for the number of wires for Hermitian observables in Lightning-Tensor. Only 1-wire Hermitian observables are supported as of cuTensorNet-v24.03.0. (#806)
Set PL_BACKEND for the entire build-wheel-lightning-gpu Docker-build stage to properly build the Lightning-GPU wheel. (#791)
Fix conditions for skipping build & push steps in the Docker build workflows. (#790)
Downgrade Scipy on Lightning stable version tests. (#783)
Fix checkout command in test workflows for rc branches. (#777)
Point to the right Lightning root folder independently from the invocation location, when configuring the project. (#874)

Contributors

This release contains contributions from (in alphabetical order):

Ali Asadi, Astral Cai, Ahmed Darwish, Amintor Dusko, Vincent Michaud-Rioux, Luis Alfredo Nuñez Meneses, Erick Ochoa Lopez, Lee J. O'Riordan, Mudit Pandey, Shuli Shu, Raul Torres, Paul Haochen Wang

Release 0.37.0

New features since last release

Implement Python interface to the lightning.tensor device. (#748)
Add inverse support for gate operations in lightning.tensor in the C++ layer. (#753)
Add observable and expval support to the cutensornet-backed lightning.tensor C++ layer. (#728)
Add gate support to cutensornet-backed lightning.tensor C++ layer. (#718)
Add cutensornet-backed MPS C++ layer to lightning.tensor. (#704)
Add support for C(BlockEncode) to Lightning devices. (#743)

Breaking changes

Removed the QuimbMPS class and the corresponding backend from lightning.tensor. (#737)
Changed the name of default.tensor to lightning.tensor with the quimb backend. (#730)
dynamic_one_shot uses shot-vectors in the auxiliary tape to tell the device how many times to repeat the tape. Lightning-Qubit is updated accordingly. (#724)
dynamic_one_shot deals with post-selection during the post-processing phase, so Lightning-Qubit does not return None-valued measurements for mismatching samples anymore. (#720)

Improvements

Release candidate branches automatically use the new large GitHub runner pool. (#769)
Lightning-Kokkos dev wheels for MacOS (x86_64, ARM64) and Linux (AArch64) are uploaded to TestPyPI upon merging a pull request. (#765)
Lightning-Kokkos Linux (x86_64) dev wheels are pushed to Test PyPI upon merging a pull request. (#763)
Change the type of tensor network objects passed to ObservablesTNCuda and MeasurementsTNCuda classes from StateTensorT to TensorNetT. (#759)
Silence NDPermuter linting warnings. (#750)
Rationalize MCM tests, removing most end-to-end tests from the native MCM test file, but keeping one that validates multiple mid-circuit measurements with any allowed return. (#754)
Rename lightning.tensor C++ libraries. (#755)
Set state_tensor as const for the MeasurementTNCuda class. (#753)
Updated Kokkos version and support to 4.3.01. (#725)
Lightning-Kokkos' functors are rewritten as functions wrapping around generic gate and generator functors templated over a coefficient interaction function. This reduces boilerplate while clarifying how the various kernels differ from one another. (#640)
Update C++ and Python GitHub actions names to include the matrix info. (#717)
Remove CPhase in favour of CPhaseShift in Lightning devices. (#717)
The various OpenMP configurations of Lightning-Qubit are tested in parallel on different Github Actions runners. (#712)
Update Linux wheels to use manylinux_2_28 images. (#667)
Add support for qml.expval and qml.var in the lightning.tensor device for the quimb interface and the MPS method. (#686)
Changed the name of lightning.tensor to default.tensor with the quimb backend. (#719)
lightning.qubit and lightning.kokkos adhere to user-specified mid-circuit measurement configuration options. (#736)
Patch the C++ Measurements.probs(wires) method in Lightning-Qubit and Lightning-Kokkos to Measurements.probs() when called with all wires. This will trigger a more optimized implementation for calculating the probabilities of the entire system. (#744)
Remove the daily schedule from the "Compat Check w/PL - release/release" GitHub action. (#746)
Remove the required scipy config file for Lightning-Qubit. The support is now maintained by passing SCIPY_LIBS_PATH to the compiler. (#775)

Documentation

Add installation instructions and documentation for lightning.tensor. (#756)

Bug fixes

Don't route probs(wires=[]) to probs(all_wires) in Lightning-Kokkos. (#762)
ControlledQubitUnitary is present in the Python device but not the TOML files. It is added to the decomposition gates since it can be implemented in its alternate form of C(QubitUnitary). (#767)
Update the Lightning TOML files to indicate that non-commuting observables are supported. (#764)
Fix regex matching issue with auto on-boarding of release candidate branch to using the large runner queue. (#774)
Fix random CI failures for lightning.tensor Python unit tests and ignore lightning_tensor paths. (#761)
lightning.qubit and lightning.kokkos use qml.ops.Conditional.base instead of qml.ops.Conditional.then_op. (#752)
The preprocessing step in lightning.qubit now uses interface information to properly support the hardware-like postselection for mid-circuit measurements. (#760)
Fix AVX streaming operation support with newer GCC. (#729)
Revert changes calling the templated IMAG, ONE, ZERO functions in Kokkos kernels since they are incompatible with device execution. (#733)
The tests_lkcpu_python.yml workflow properly checks out the release or stable version of Lightning-Qubit during the test job. (#723)
Fix PennyLane Lightning-Kokkos and Lightning-Qubit tests for stable/stable configuration. (#734)
Remove the Autoray dependency from requirement files. (#736)
Fix the cuda-runtime-12-0 dependency issue on RHEL8. (#739)
Fix the memory segmentation fault when initializing zero-wire Lightning-Kokkos. (#757)
Remove pennylane.ops.op_math.controlled_decompositions.ctrl_decomp_zyz tests with len(control_wires) > 1. (#757)
Add support for Scipy v1.14. (#776)
Add pickle support for the DevPool object in lightning.gpu. (#772)

Contributors

This release contains contributions from (in alphabetical order):

Ali Asadi, Amintor Dusko, Lillian Frederiksen, Pietropaolo Frisoni, David Ittah, Vincent Michaud-Rioux, Lee James O'Riordan, Mudit Pandey, Shuli Shu, Jay Soni

Release 0.36.0

New features since last release

Add cutensornet-backed MPS C++ layer to lightning.tensor. (#704)
Add Python class for the lightning.tensor device which uses the new device API and the interface for quimb based on the MPS method. (#671)
Add compile-time support for AVX2/512 streaming operations in lightning.qubit. (#664)
lightning.kokkos supports mid-circuit measurements. (#672)
Add dynamic linking to LAPACK/OpenBlas shared objects in scipy.libs for both C++ and Python layer. (#653)
lightning.qubit supports mid-circuit measurements. (#650)
Add finite shots support in lightning.qubit2. (#630)
Add collapse and normalize methods to the StateVectorLQubit classes, enabling "branching" of the wavefunction. Add methods to create and seed an RNG in the Measurements modules. (#645)
Add two new Python classes (LightningStateVector and LightningMeasurements) to support lightning.qubit2. (#613)
Add analytic-mode qml.probs and qml.var support in lightning.qubit2. (#627)
Add LightningAdjointJacobian to support lightning.qubit2. (#631)
Add lightning.qubit2 device which uses the new device API. (#607) (#628)
Add Vector-Jacobian Product calculation support to lightning.qubit. (#644)
Add support for using new operator arithmetic as the default. (#649)

Breaking changes

Split Lightning-Qubit and Lightning-Kokkos CPU Python tests with pytest-split. Remove SERIAL from Kokkos' exec_model matrix. Remove all from Lightning-Kokkos' pl_backend matrix. Move clang-tidy checks to tidy.yml. Avoid editable pip installations. (#696)
Update lightning.gpu and lightning.kokkos to raise an error instead of falling back to default.qubit. (#689)
Add paths directives to test workflows to avoid running tests that cannot be impacted by changes. (#699) (#695)
Move common components of /src/simulator/lightning_gpu/utils/ to /src/utils/cuda_utils/. (#676)
Deprecate static LAPACK linking support. (#653)
Migrate lightning.qubit to the new device API. (#646)
Introduce ci:build_wheels label, which controls wheel building on pull_request and other triggers. (#648)
Remove building wheels for Lightning Kokkos on Windows. (#693)

Improvements

Add tests for Windows Wheels, fix ill-defined caching, and set the proper backend for lightning.kokkos wheels. (#693)
Replace string comparisons by isinstance checks where possible. (#691)
Refactor cuda_utils to remove its dependency on custatevec.h. (#681)
Add test_templates.py module where Grover and QSVT are tested. (#684)
Create cuda_utils for common usage of CUDA related backends. (#676)
Refactor lightning_gpu_utils unit tests to remove the dependency on statevector class. (#675)
Upgrade GitHub actions versions from v3 to v4. (#669)
Initialize the private attributes gates_indices_ and generators_indices_ of StateVectorKokkos using the definitions of the Pennylane::Gates::Constant namespace. (#641)
Add isort to requirements-dev.txt and run before black upon make format to sort Python imports. (#623)
Improve support for new operator arithmetic with QuantumScriptSerializer.serialize_observables. (#670)
Add workflow_dispatch to wheels recipes; allowing developers to build wheels manually on a branch instead of temporarily changing the headers. (#679)
Add the ENABLE_LAPACK compilation flag to toggle dynamic linking to LAPACK library. (#678)

Documentation

Bug fixes

Fix wire order permutations when using qml.probs with out-of-order wires in Lightning-Qubit. (#707)
Lightning-Qubit once again respects the wire order specified on device instantiation. (#705)
dynamic_one_shot was refactored to use SampleMP measurements as a way to return the mid-circuit measurement samples. LightningQubit's simulate` is modified accordingly. (#694)
Lightning-Qubit correctly decomposes state prep operations when used in the middle of a circuit. (#687)
Lightning-Qubit correctly decomposes qml.QFT and qml.GroverOperator if len(wires) is greater than 9 and 12 respectively. (#687)
Specify isort --py (Python version) and -l (max line length) to stabilize isort across Python versions and environments. (#647)
Fix random coverage xml CI issues. (#635)
lightning.qubit correctly decomposed state preparation operations with adjoint differentiation. (#661)
Fix the failed observable serialization unit tests. (#683)
Update the Lightning-Qubit new device API to work with Catalyst. (#665)
Update the version of codecov-action to v4 and fix the CodeCov issue with the PL-Lightning check-compatibility actions. (#682)
Refactor of dev prerelease auto-update-version workflow. (#685)
Remove gates unsupported by catalyst from TOML file. (#698)
Increase tolerance for a flaky test. (#703)
Remove ControlledQubitUnitary in favour of C(QubitUnitary) from the list of supported operations and the device TOML file. The stopping_condition method guarantees the consistency of decompositions. (#758)
Raise a clear error message with initialization of lightning.kokkos with zero-qubit on Windows. (#758)

Contributors

This release contains contributions from (in alphabetical order):

Ali Asadi, Amintor Dusko, Pietropaolo Frisoni, Thomas Germain, Christina Lee, Erick Ochoa Lopez, Vincent Michaud-Rioux, Rashid N H M, Lee James O'Riordan, Mudit Pandey, Shuli Shu

Release 0.35.1

Improvements

Use the adjoint gate parameter to apply qml.Adjoint operations instead of matrix methods in lightning.qubit. (#632)

Bug fixes

Fix qml.Adjoint support in lightning.gpu and lightning.kokkos. (#632)
Fix finite shots support in lightning.qubit, lightning.gpu and lightning.kokkos. The bug would impact calculations with measurements on observables with non-trivial diagonalizing gates and calculations with shot vectors. (#632)

Contributors

This release contains contributions from (in alphabetical order):

Vincent Michaud-Rioux

Release 0.35.0

New features since last release

All backends now support GlobalPhase and C(GlobalPhase) in forward pass. (#579)
Add Hermitian observable support for shot-noise measurement and Lapack support. (#569)

Breaking changes

Migrate lightning.gpu to CUDA 12. (#606)

Improvements

Expand error values and strings returned from CUDA libraries. (#617)
C(MultiRZ) and C(Rot) gates are natively supported (with LM kernels). (#614)
Add adjoint support for GlobalPhase in Lightning-GPU and Lightning-Kokkos. (#615)
Lower the overheads of Windows CI tests. (#610)
Decouple LightningQubit memory ownership from numpy and migrate it to Lightning-Qubit managed state-vector class. (#601)
Expand support for Projector observables on Lightning-Kokkos. (#601)
Split Docker build cron job into two jobs: master and latest. This is mainly for reporting in the plugin-test-matrix repo. (#600)
The BlockEncode operation from PennyLane is now supported on all Lightning devices. (#599)
OpenMP acceleration can now be enabled at compile time for all lightning.qubit gate kernels using the -DLQ_ENABLE_KERNEL_OMP=1 CMake argument. (#510)
Enable building Docker images for any branch or tag. Set the Docker build cron job to build images for the latest release and master. (#598)
Enable choosing the PennyLane-Lightning version and disabling push to Docker Hub in the Docker build workflow. Add a cron job calling the Docker build workflow. (#597)
Pull Kokkos v4.2.00 from the official Kokkos repository to test Lightning-Kokkos with the CUDA backend. (#596)
Remove deprecated MeasurementProcess.name. (#605)

Documentation

Update requirements to build the documentation. (#594)

Bug fixes

Downgrade auditwheel due to changes with library exclusion list. (#620)
List GlobalPhase gate in each device's TOML file. (#615)
Lightning-GPU's gate cache failed to distinguish between certain gates. For example, MultiControlledX([0, 1, 2], "111") and MultiControlledX([0, 2], "00") were applied as the same operation. This could happen with (at least) the following gates: QubitUnitary,ControlledQubitUnitary,MultiControlledX,DiagonalQubitUnitary,PSWAP,OrbitalRotation. (#579)
Ensure the stopping condition decompositions are respected for larger templated QFT and Grover operators. (#609)
Move concurrency group specifications from reusable Docker build workflow to the root workflows. (#604)
Fix lightning-kokkos-cuda Docker build and add CI workflow to build images and push to Docker Hub. (#593)
Update jax.config imports. (#619)
Fix apply state vector when using a Lightning handle. (#622)
Pinning Pytest to a version compatible with Flaky. (#624)

Contributors

This release contains contributions from (in alphabetical order):

Amintor Dusko, David Ittah, Vincent Michaud-Rioux, Lee J. O'Riordan, Shuli Shu, Matthew Silverman

Release 0.34.0

New features since last release

Support added for Python 3.12 wheel builds. (#541)
Lightning-Qubit support arbitrary controlled gates (any wires and any control values). The kernels are implemented in the LM module. (#576)
Shot-noise related methods now accommodate observable objects with arbitrary eigenvalues. Add a Kronecker product method for two diagonal matrices. (#570)
Add shot-noise support for probs in the C++ layer. Probabilities are calculated from generated samples. All Lightning backends support this feature. Please note that target wires should be sorted in ascending manner. (#568)
Add LM kernels to apply arbitrary controlled operations efficiently. (#516)
Add shots support for variance value, probs, sample, counts calculation for given observables (NamedObs, TensorProd and Hamiltonian) based on Pauli words, Identity and Hadamard in the C++ layer. All Lightning backends support this support feature. (#561)
Add shots support for expectation value calculation for given observables (NamedObs, TensorProd and Hamiltonian) based on Pauli words, Identity and Hadamard in the C++ layer by adding measure_with_samples to the measurement interface. All Lightning backends support this support feature. (#556)
qml.QubitUnitary operators can be included in a circuit differentiated with the adjoint method. Lightning handles circuits with arbitrary non-differentiable qml.QubitUnitary operators. 1,2-qubit qml.QubitUnitary operators with differentiable parameters can be differentiated using decomposition. [(#540)] (#540)

Breaking changes

Set the default version of Kokkos to 4.2.00 throughout the project (CMake, CI, etc.) [(#578)] (#578)
Overload applyOperation with a fifth matrix argument to all state vector classes to support arbitrary operations in AdjointJacobianBase. [(#540)] (#540)

Improvements

Ensure aligned memory used for numpy arrays with state-vector without reallocations. (#572)
Unify error messages of shot measurement related unsupported observables to better Catalyst. (#577)
Add configuration files to improve compatibility with Catalyst. (#566)
Refactor shot-noise related methods of MeasurementsBase class in the C++ layer and eigenvalues are not limited to 1 and -1. Add getObs() method to Observables class. Refactor applyInPlaceShots to allow users to get eigenvalues of Observables object. Deprecated _preprocess_state method in MeasurementsBase class for safer use of the LightningQubitRaw backend. (#570)
Modify setup.py to use backend-specific build directory (f"build_{backend}") to accelerate rebuilding backends in alternance. [(#540)] (#540)
Update Dockerfile and rewrite the build-wheel-lightning-gpu stage to build Lightning-GPU from the pennylane-lightning monorepo. [(#539)] (#539)
Add the MPI test CI workflows of Lightning-GPU in compatibility cron jobs. [(#536)] (#536)
Add MPI synchronization in places to safely handle communicated data. (#538)
Add release option in compatibility cron jobs to test the release candidates of PennyLane and the Lightning plugins against one another. [(#531)] (#531)
Add GPU workflows in compatibility cron jobs to test Lightning-GPU and Lightning-Kokkos with the Kokkos CUDA backend. [(#528)] (#528)

Documentation

Fixed a small typo in the documentation page for the PennyLane-Lightning GPU device. (#563)
Add OpenGraph social preview for Lightning docs. (#574)

Bug fixes

Fix CodeCov file contention issue when uploading data from many workloads. (#584)
Ensure the lightning.gpu intermediate wheel builds are uploaded to TestPyPI. (#575)
Allow support for newer clang-tidy versions on non-x86_64 platforms. (#567)
Do not run C++ tests when testing for compatibility with PennyLane, hence fixing plugin-matrix failures. Fix Lightning-GPU workflow trigger. (#571)
Revert single-node multi-GPU batching behaviour to match PennyLaneAI/pennylane-lightning-gpu#27. (#564)
Move deprecated stateprep QuantumScript argument into the operation list in mpitests/test_adjoint_jacobian.py. [(#540)] (#540)
Fix MPI Python unit tests for the adjoint method. (#538)
Fix the issue with assigning kernels to ops before registering kernels on macOS (#582)
Update MANIFEST.in to include device config files and CHANGELOG.md (#585)

Contributors

This release contains contributions from (in alphabetical order):

Ali Asadi, Isaac De Vlugt, Amintor Dusko, Vincent Michaud-Rioux, Erick Ochoa Lopez, Lee James O'Riordan, Shuli Shu

Release 0.33.1

pip-installed CUDA runtime libraries can now be accessed from a virtualenv. (#543)

Bug fixes

The pybind11 compiled module RPATH linkage has been restored to pre-0.33 behaviour. (#543)

Contributors

This release contains contributions from (in alphabetical order):

Lee J. O'Riordan

Release 0.33.0

New features since last release

Add documentation updates for the lightning.gpu backend. [(#525)] (#525)
Add SparseHamiltonian support for Lightning-Qubit and Lightning-GPU. [(#526)] (#526)
Add SparseHamiltonian support for Lightning-Kokkos. [(#527)] (#527)
Integrate python/pybind layer of distributed Lightning-GPU into the Lightning monorepo with Python unit tests. [(#518)] (#518)
Integrate the distributed C++ backend of Lightning-GPU into the Lightning monorepo. [(#514)] (#514)
Integrate Lightning-GPU into the Lightning monorepo. The new backend is named lightning.gpu and includes all single-GPU features. [(#499)] (#499)
Build Linux wheels for Lightning-GPU (CUDA-11). (#517)
Add Dockerfile in docker and make docker workflow in Makefile. The Docker images and documentation are available on DockerHub. (#496)
Add mid-circuit state preparation operation tests. (#495)

Breaking changes

Add tests_gpu.yml workflow to test the Lightning-Kokkos backend with CUDA-12. (#494)
Implement LM::GeneratorDoubleExcitation, LM::GeneratorDoubleExcitationMinus, LM::GeneratorDoubleExcitationPlus kernels. Lightning-Qubit default kernels are now strictly from the LM implementation, which requires less memory and is faster for large state vectors. (#512)
Add workflows validating compatibility between PennyLane and Lightning's most recent stable releases and development (latest) versions. (#507) (#498)
Introduce timeout-minutes in various workflows, mainly to avoid Windows builds hanging for several hours. (#503)
Cast integral-valued arrays to the device's complex type on entry in _preprocess_state_vector to ensure the state is correctly represented with floating-point numbers. (#501)
Update DefaultQubit to DefaultQubitLegacy on Lightning fallback. (#500)
Enums defined in GateOperation.hpp start at 1 (previously 0). ::BEGIN is introduced in a few places where it was assumed 0 accordingly. (#485)
Enable pre-commit hooks to format all Python files and linting of all Python source files. (#485)

Improvements

Improve Python testing for Lightning-GPU (+MPI) by adding jobs in Actions files and adding Python tests to increase code coverage. (#522)
Add support for pip install pennylane-lightning[kokkos] for the OpenMP backend. (#515)
Update setup.py to allow for multi-package co-existence. The PennyLane_Lightning package now is the responsible for the core functionality, and will be depended upon by all other extensions. [(#504)] (#504)
Redesign Lightning-Kokkos StateVectorKokkos class to use Kokkos RangePolicy together with special functors in applyMultiQubitOp to apply 1- to 4-wire generic unitary gates. For more than 4 wires, the general implementation using Kokkos TeamPolicy is employed to yield the best all-around performance. [(#490)] (#490)
Redesign Lightning-Kokkos Measurements class to use Kokkos RangePolicy together with special functors to obtain the expectation value of 1- to 4-wire generic unitary gates. For more than 4 wires, the general implementation using Kokkos TeamPolicy is employed to yield the best all-around performance. [(#489)] (#489)
Add tests to increase Lightning-Kokkos coverage. (#485)
Add memory locality tag reporting and adjoint diff dispatch for lightning.qubit statevector classes. (#492)
Add support for dependent external packages to C++ core. (#482)
Add support for building multiple backend simulators. (#497)

Documentation

Bug fixes

Fix CI issues running python-cov with MPI. (#535)
Re-add support for pip install pennylane-lightning[gpu]. (#515)
Switch most Lightning-Qubit default kernels to LM. Add LM::multiQubitOp tests, failing when targeting out-of-order wires clustered close to num_qubits-1. Fix the LM::multiQubitOp kernel implementation by introducing a generic revWireParity routine and replacing the bitswap-based implementation. Mimic the changes fixing the corresponding multiQubitOp and expval functors in Lightning-Kokkos. (#511)
Fix RTD builds by removing unsupported system_packages configuration option. (#491)

Contributors

This release contains contributions from (in alphabetical order):

Ali Asadi, Amintor Dusko, Vincent Michaud-Rioux, Lee J. O'Riordan, Shuli Shu

Release 0.32.0

New features since last release

The lightning.kokkos backend supports Nvidia GPU execution (with Kokkos v4 and CUDA v12). (#477)
Complete overhaul of repository structure to facilitates integration of multiple backends. Refactoring efforts we directed to improve development performance, code reuse and decrease overall overhead to propagate changes through backends. New C++ modular build strategy allows for faster test builds restricted to a module. Update CI/CD actions concurrency strategy. Change minimal Python version to 3.9. [(#472)] (#472)
Wheels are built with native support for sparse Hamiltonians. [(#470)] (#470)
Add native support to sparse Hamiltonians in the absence of Kokkos & Kokkos-kernels. [(#465)] (#465)

Breaking changes

Rename QubitStateVector to StatePrep in the Lightning-Qubit and Lightning-Kokkos classes. (#486)
Modify adjointJacobian methods to accept a (maybe unused) reference StateVectorT, allowing device-backed simulators to directly access state vector data for adjoint differentiation instead of copying it back-and-forth into JacobianData (host memory). (#477)

Improvements

Refactor LKokkos Measurements class to use (fast) specialized functors whenever possible. [(#481)] (#481)
Merge Lightning Qubit and Lightning Kokkos backends in the new repository. [(#472)] (#472)
Integrated new unified docs for Lightning Kokkos and Lightning Qubit packages. [(#473)] (#473)

Documentation

Bug fixes

Ensure PennyLane has an active_return attribute before calling it. [(#483)] (#483)
Do no import sqrt2_v from <numbers> in Util.hpp to resolve issue with Lightning-GPU builds. (#479)
Update the CMake internal references to enable sub-project compilation with affecting the parent package. (#478)
apply no longer mutates the inputted list of operations. (#474)

Contributors

This release contains contributions from (in alphabetical order):

Amintor Dusko, Christina Lee, Vincent Michaud-Rioux, Lee J. O'Riordan

Release 0.31.0

New features since last release

Update Kokkos support to 4.0.01. [(#439)] (#439)

Breaking changes

Update tests to be compliant with PennyLane v0.31.0 development changes and deprecations. (#448)

Improvements

Remove logic from setup.py and transfer paths and env variable definitions into workflow files. (#450)
Detect MKL or CBLAS if ENABLE_BLAS=ON making sure that BLAS is linked as expected. (#449)

Documentation

Fix LightningQubit class parameter documentation. (#456)

Bug fixes

Ensure cross-platform wheels continue to build with updates in git safety checks. (#452)
Fixing Python version bug introduce in (#450) when Python_EXECUTABLE was removed from setup.py. (#461)
Ensure aligned allocator definition works with C++20 compilers. (#438)
Prevent multiple threads from calling Kokkos::initialize or Kokkos::finalize. (#439)

Contributors

This release contains contributions from (in alphabetical order):

Vincent Michaud-Rioux, Lee J. O'Riordan, Chae-Yeun Park

Release 0.30.0

New features since last release

Add MCMC sampler. [(#384)] (#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

Release 0.29.0

Improvements

Remove runtime dependency on ninja build system. (#414)
Allow better integration and installation support with CMake targeted binary builds. (#403)
Remove explicit Numpy and Scipy requirements. (#412)
Get llvm installation root from the environment variable LLVM_ROOT_DIR (or fallback to brew). (#413)
Update AVX2/512 kernel infrastructure for additional gate/generator operations. (#404)
Remove unnecessary lines for resolving CodeCov issue. (#415)
Add more AVX2/512 gate operations. (#393)

Documentation

Bug fixes

Ensure error raised when asking for out of order marginal probabilities. Prevents the return of incorrect results. (#416)
Fix Github shields in README. (#402)

Contributors

Amintor Dusko, Vincent Michaud-Rioux, Lee James O'Riordan, Chae-Yeun Park

Release 0.28.2

Bug fixes

Fix Python module versioning for Linux wheels. (#408)

Contributors

This release contains contributions from (in alphabetical order):

Amintor Dusko, Shuli Shu, Trevor Vincent

Release 0.28.1

Bug fixes

Fix Pybind11 module versioning and locations for Windows wheels. (#400)

Contributors

This release contains contributions from (in alphabetical order):

Lee J. O'Riordan

Release 0.28.0

Breaking changes

Deprecate support for Python 3.7. (#391)

Improvements

Improve Lightning package structure for external use as a C++ library. (#369)
Improve the stopping condition method. (#386)

Bug fixes

Pin CMake to 3.24.x in wheel-builder to avoid Python not found error in CMake 3.25, when building wheels for PennyLane-Lightning-GPU. (#387)

Contributors

This release contains contributions from (in alphabetical order):

Amintor Dusko, Lee J. O'Riordan

Release 0.27.0

New features since last release

Enable building of Python 3.11 wheels and upgrade Python on CI/CD workflows to 3.8. (#381)

Breaking changes

Improvements

Update clang-tools version in Github workflows. (#351)
Improve tests and checks CI/CD pipelines. (#353)
Implement 3 Qubits gates (CSWAP & Toffoli) & 4 Qubits gates (DoubleExcitation, DoubleExcitationMinus, DoubleExcitationPlus) in LM manner. (#362)
Upgrade Kokkos and Kokkos Kernels to 3.7.00, and improve sparse matrix-vector multiplication performance and memory usage. (#361)
Update Linux (ubuntu-latest) architecture x86_64 wheel-builder from GCC 10.x to GCC 11.x. (#373)
Update gcc and g++ 10.x to 11.x in CI tests. This update brings improved support for newer C++ features. (#370)
Change Lightning to inherit from QubitDevice instead of DefaultQubit. (#365)

Documentation

Bug fixes

Use mutex when accessing cache in KernelMap. (#382)

Contributors

This release contains contributions from (in alphabetical order):

Amintor Dusko, Chae-Yeun Park, Monit Sharma, Shuli Shu

Release 0.26.1

Bug fixes

Fixes the transposition method used in the probability calculation. (#377)

Contributor

Amintor Dusko

Release 0.26.0

Improvements

Introduces requirements-dev.txt and improves dockerfile. (#330)
Support expval for a Hamiltonian. (#333)
Implements caching for Kokkos installation. (#316)
Supports measurements of operator arithmetic classes such as Sum, Prod, and SProd by deferring handling of them to DefaultQubit. (#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)
Updates to the release tagger to fix incompatibilities with RTD. (#344)
Update cancel-workflow-action and bot credentials. (#345)

Contributors

This release contains contributions from (in alphabetical order):

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

Release 0.25.0

New features since last release

Breaking changes

We explicitly disable support for PennyLane's parameter broadcasting. #317
We explicitly remove support for PennyLane's Sum, SProd and Prod as observables. (#326)

Improvements

CI builders use a reduced set of resources and redundant tests for PRs. (#319)
Parallelize wheel-builds where applicable. (#314)
AVX2/512 kernels are now available on Linux/MacOS with x86-64 architecture. (#313)

Documentation

Updated ReadTheDocs runner version from Ubuntu 20.04 to 22.04 (#327)

Bug fixes

Test updates to reflect new additions to PennyLane. (#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

Release 0.24.0

New features since last release

Add SingleExcitation and DoubleExcitation qchem gates and generators. (#289)
Add a new dispatch mechanism for future kernels. (#291)
Add IsingXY gate operation. (#303)
Support qml.state() in vjp and Hamiltonian in adjoint jacobian. (#294)

Breaking changes

Codebase is now moving to C++20. The default compiler for Linux is now GCC10. (#295)
Minimum macOS version is changed to 10.15 (Catalina). (#295)

Improvements

Split matrix operations, refactor dispatch mechanisms, and add a benchmark suits. (#274)
Add native support for the calculation of sparse Hamiltonians' expectation values. Sparse operations are offloaded to Kokkos and Kokkos-Kernels. (#283)
Device lightning.qubit now accepts a datatype for a statevector. (#290)

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 to style the Sphinx documentation. (#287)

Bug fixes

Fix the issue with using available clang-format version in format. (#288)
Fix a bug in the generator of DoubleExcitationPlus. (#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

Release 0.23.0

New features since last release

Add generate_samples() to lightning. (#247)
Add Lightning GBenchmark Suite. (#249)
Support runtime and compile information. (#253)

Improvements

Add ENABLE_BLAS build to CI checks. (#249)
Add more clang-tidy checks and kernel tests. (#253)
Add C++ code coverage to CI. (#265)
Skip over identity operations in "lightning.qubit". (#268)

Bug fixes

Update tests to remove JacobianTape. (#260)
Fix tests for MSVC. (#264)
Fix #include <cpuid.h> for PPC and AArch64 in Linux. (#266)
Remove deprecated tape execution methods. (#270)
Update qml.probs in test_measures.py. (#280)

Contributors

This release contains contributions from (in alphabetical order):

Ali Asadi, Chae-Yeun Park, Lee James O'Riordan, and Trevor Vincent

Release 0.22.1

Bug fixes

Ensure Identity kernel is registered to C++ dispatcher. (#275)

Release 0.22.0

New features since last release

Add Docker support. (#234)

Improvements

Update quantum tapes serialization and Python tests. (#239)
Clang-tidy is now enabled for both tests and examples builds under Github Actions. (#237)
The return type of StateVectorBase data is now derived-class defined. (#237)
Update adjointJacobian and VJP methods. (#222)
Set GitHub workflow to upload wheels to Test PyPI. (#220)
Finalize the new kernel implementation. (#212)

Documentation

Use of batching with OpenMP threads is documented. (#221)

Bug fixes

Fix for OOM errors when using adjoint with large numbers of observables. (#221)
Add virtual destructor to C++ state-vector classes. (#200)
Fix a bug in Python tests with operations' matrix calls. (#238)
Refactor utility header and fix a bug in linear algebra function with CBLAS. (#228)

Contributors

This release contains contributions from (in alphabetical order):

Ali Asadi, Chae-Yeun Park, Lee James O'Riordan

Release 0.21.0

New features since last release

Add C++ only benchmark for a given list of gates. (#199)
Wheel-build support for Python 3.10. (#186)
C++ support for probability, expectation value and variance calculations. (#185)
Add bindings to C++ expval, var, probs. (#214)

Improvements

setup.py adds debug only when --debug is given (#208)
Add new highly-performant C++ kernels for quantum gates. (#202)

The new kernels significantly improve the runtime performance of PennyLane-Lightning for both differentiable and non-differentiable workflows. Here is an example workflow using the adjoint differentiation method with a circuit of 5 strongly entangling layers:

import pennylane as qml
from pennylane import numpy as np
from pennylane.templates.layers import StronglyEntanglingLayers
from numpy.random import random
np.random.seed(42)
n_layers = 5
n_wires = 6
dev = qml.device("lightning.qubit", wires=n_wires)

@qml.qnode(dev, diff_method="adjoint")
def circuit(weights):
    StronglyEntanglingLayers(weights, wires=list(range(n_wires)))
    return [qml.expval(qml.PauliZ(i)) for i in range(n_wires)]

init_weights = np.random.random(StronglyEntanglingLayers.shape(n_layers=n_layers, n_wires=n_wires))
params = np.array(init_weights,requires_grad=True)
jac = qml.jacobian(circuit)(params)

The latest release shows improved performance on both single and multi-threaded evaluations!

Ensure debug info is built into dynamic libraries. (#201)

Documentation

New guidelines on adding and benchmarking C++ kernels. (#202)

Bug fixes

Update clang-format version (#219)
Fix failed tests on Windows. (#218)
Update clang-format version (#219)
Add virtual destructor to C++ state-vector classes. (#200)
Fix failed tests for the non-binary wheel. (#213)
Add virtual destructor to C++ state-vector classes. (#200)

Contributors

This release contains contributions from (in alphabetical order):

Ali Asadi, Amintor Dusko, Chae-Yeun Park, Lee James O'Riordan

Release 0.20.1

Bug fixes

Fix missing header-files causing build errors in algorithms module. (#193)
Fix failed tests for the non-binary wheel. (#191)

Release 0.20.2

Bug fixes

Introduce CY kernel to Lightning to avoid issues with decomposition. (#203)

Contributors

This release contains contributions from (in alphabetical order):

Lee J. O'Riordan

Release 0.20.1

Bug fixes

Fix missing header-files causing build errors in algorithms module. (#193)
Fix failed tests for the non-binary wheel. (#191)

Release 0.20.0

New features since last release

Add wheel-builder support for Python 3.10. (#186)
Add VJP support to PL-Lightning. (#181)
Add complex64 support in PL-Lightning. (#177)
Added examples folder containing aggregate gate performance test. (#165)

Breaking changes

Improvements

Update PL-Lightning to support new features in PL. (#179)

Documentation

Lightning setup.py build process uses CMake. (#176)

Contributors

This release contains contributions from (in alphabetical order):

Ali Asadi, Chae-Yeun Park, Isidor Schoch, Lee James O'Riordan

Release 0.19.0

Add Cache-Friendly DOTC, GEMV, GEMM along with BLAS Support. (#155)

Improvements

The performance of parametric gates has been improved. (#157)
AVX support is enabled for Linux users on Intel/AMD platforms. (#157)
PennyLane-Lightning has been updated to conform with clang-tidy recommendations for modernization, offering performance improvements across all use-cases. (#153)

Breaking changes

Linux users on x86_64 must have a CPU supporting AVX. (#157)

Bug fixes

OpenMP built with Intel MacOS CI runners causes failures on M1 Macs. OpenMP is currently disabled in the built wheels until this can be resolved with Github Actions runners. (#166)

Contributors

This release contains contributions from (in alphabetical order):

Ali Asadi, Lee James O'Riordan

Release 0.18.0

New features since last release

PennyLane-Lightning now provides a high-performance adjoint Jacobian method for differentiating quantum circuits. (#136)

The adjoint method operates after a forward pass by iteratively applying inverse gates to scan backwards through the circuit. The method is already available in PennyLane's default.qubit device, but the version provided by lightning.qubit integrates with the C++ backend and is more performant, as shown in the plot below:

The plot compares the average runtime of lightning.qubit and default.qubit for calculating the Jacobian of a circuit using the adjoint method for a range of qubit numbers. The circuit consists of ten BasicEntanglerLayers with a PauliZ expectation value calculated on each wire, repeated over ten runs. We see that lightning.qubit provides a speedup of around two to eight times, depending on the number of qubits.

The adjoint method can be accessed using the standard interface. Consider the following circuit:
```
import pennylane as qml

wires = 3
layers = 2
dev = qml.device("lightning.qubit", wires=wires)

@qml.qnode(dev, diff_method="adjoint")
def circuit(weights):
    qml.templates.StronglyEntanglingLayers(weights, wires=range(wires))
    return qml.expval(qml.PauliZ(0))

weights = qml.init.strong_ent_layers_normal(layers, wires, seed=1967)
```
The circuit can be executed and its gradient calculated using:
```
>>> print(f"Circuit evaluated: {circuit(weights)}")
Circuit evaluated: 0.9801286266677633
>>> print(f"Circuit gradient:\n{qml.grad(circuit)(weights)}")
Circuit gradient:
[[[-1.11022302e-16 -1.63051504e-01 -4.14810501e-04]
[ 1.11022302e-16 -1.50136528e-04 -1.77922957e-04]
[ 0.00000000e+00 -3.92874550e-02  8.14523075e-05]]

[[-1.14472273e-04  3.85963953e-02  0.00000000e+00]
[-5.76791765e-05 -9.78478343e-02  0.00000000e+00]
[-5.55111512e-17  0.00000000e+00 -1.11022302e-16]]]
```
PennyLane-Lightning now supports all of the operations and observables of default.qubit. (#124)

Improvements

A new state-vector class StateVectorManaged was added, enabling memory use to be bound to statevector lifetime. (#136)
The repository now has a well-defined component hierarchy, allowing each indepedent unit to be compiled and linked separately. (#136)
PennyLane-Lightning can now be installed without compiling its C++ binaries and will fall back to using the default.qubit implementation. Skipping compilation is achieved by setting the SKIP_COMPILATION environment variable, e.g., Linux/MacOS: export SKIP_COMPILATION=True, Windows: set SKIP_COMPILATION=True. This feature is intended for building a pure-Python wheel of PennyLane-Lightning as a backup for platforms without a dedicated wheel. (#129)
The C++-backed Python bound methods can now be directly called with wires and supplied parameters. (#125)
Lightning supports arbitrary unitary and non-unitary gate-calls from Python to C++ layer. (#121)

Documentation

Added preliminary architecture diagram for package. (#131)
C++ API built as part of docs generation. (#131)

Breaking changes

Wheels for MacOS <= 10.13 will no longer be provided due to XCode SDK C++17 support requirements. (#149)

Bug fixes

An indexing error in the CRY gate is fixed. (#136)
Column-major data in numpy is now correctly converted to row-major upon pass to the C++ layer. (#126)

Contributors

This release contains contributions from (in alphabetical order):

Thomas Bromley, Lee James O'Riordan

Release 0.17.0

New features

C++ layer now supports float (32-bit) and double (64-bit) templated complex data. (#113)

Improvements

The PennyLane device test suite is now included in coverage reports. (#123)
Static versions of jQuery and Bootstrap are no longer included in the CSS theme. (#118)
C++ tests have been ported to use Catch2 framework. (#115)
Testing now exists for both float and double precision methods in C++ layer. (#113) (#115)
Compile-time utility methods with constexpr have been added. (#113)
Wheel-build support for ARM64 (Linux and MacOS) and PowerPC (Linux) added. (#110)
Add support for Controlled Phase Gate (ControlledPhaseShift). (#114)
Move changelog to .github and add a changelog reminder. (#111)
Adds CMake build system support. (#104)

Breaking changes

Removes support for Python 3.6 and adds support for Python 3.9. (#127) (#128)
Compilers with C++17 support are now required to build C++ module. (#113)
Gate classes have been removed with functionality added to StateVector class. (#113)
We are no longer building wheels for Python 3.6. (#106)

Bug fixes

PowerPC wheel-builder now successfully compiles modules. (#120)

Documentation

Added community guidelines. (#109)

Contributors

This release contains contributions from (in alphabetical order):

Ali Asadi, Christina Lee, Thomas Bromley, Lee James O'Riordan

Release 0.15.1

Bug fixes

The PennyLane-Lightning binaries are now built with NumPy 1.19.5, to avoid ABI compatibility issues with the latest NumPy 1.20 release. See the NumPy release notes for more details. (#97)

Contributors

This release contains contributions from (in alphabetical order):

Josh Izaac, Antal Száva

Release 0.15.0

Improvements

For compatibility with PennyLane v0.15, the analytic keyword argument has been removed. Statistics can still be computed analytically by setting shots=None. (#93)
Inverse gates are now supported. (#89)
Add new lightweight backend with performance improvements. (#57)
Remove the previous Eigen-based backend. (#67)

Bug fixes

Re-add dispatch table after fixing static initialisation order issue. (#68)

Contributors

This release contains contributions from (in alphabetical order):

Thomas Bromley, Theodor Isacsson, Christina Lee, Thomas Loke, Antal Száva.

Release 0.14.1

Bug fixes

Fixes a bug where the QNode would swap Lightning-Qubit to DefaultQubitAutograd on device execution due to the inherited passthru_devices entry of the capabilities dictionary. (#61)

Contributors

This release contains contributions from (in alphabetical order):

Antal Száva

Release 0.14.0

Improvements

Extends support from 16 qubits to 50 qubits. (#52)

Bug fixes

Updates applying basis state preparations to correspond to the changes in DefaultQubit. (#55)

Contributors

This release contains contributions from (in alphabetical order):

Thomas Loke, Tom Bromley, Josh Izaac, Antal Száva

Release 0.12.0

Bug fixes

Updates capabilities dictionary to be compatible with core PennyLane (#45)
Fix install of Eigen for CI wheel building (#44)

Contributors

This release contains contributions from (in alphabetical order):

Tom Bromley, Josh Izaac, Antal Száva

Release 0.11.0

Initial release.

This release contains contributions from (in alphabetical order):

Tom Bromley, Josh Izaac, Nathan Killoran, Antal Száva

Files

CHANGELOG.md

Latest commit

History

CHANGELOG.md

File metadata and controls

Release 0.40.0-dev

New features since last release

Breaking changes

Improvements

Documentation

Bug fixes

Contributors

Release 0.39.0

New features since last release

Breaking changes

Improvements

Documentation

Bug fixes

Contributors

Release 0.38.0

New features since last release

Breaking changes

Improvements

Documentation

Bug fixes

Contributors

Release 0.37.0

New features since last release

Breaking changes

Improvements

Documentation

Bug fixes

Contributors

Release 0.36.0

New features since last release

Breaking changes

Improvements

Documentation

Bug fixes

Contributors

Release 0.35.1

Improvements

Bug fixes

Contributors

Release 0.35.0

New features since last release

Breaking changes

Improvements

Documentation

Bug fixes

Contributors

Release 0.34.0

New features since last release

Breaking changes

Improvements

Documentation

Bug fixes

Contributors

Release 0.33.1

Bug fixes

Contributors

Release 0.33.0

New features since last release

Breaking changes

Improvements

Documentation

Bug fixes

Contributors

Release 0.32.0

New features since last release

Breaking changes

Improvements

Documentation

Bug fixes

Contributors

Release 0.31.0

New features since last release

Breaking changes

Improvements