Merge branch 'master' into deprecate_QubitStateVector

.github/workflows/install_deps/action.yml

@@ -15,23 +15,23 @@ inputs:
  jax_version:
  description: The version of JAX to install for any job that requires JAX
  required: false
- default: 0.4.23
+ default: '0.4.23'
  install_tensorflow:
  description: Indicate if TensorFlow should be installed or not
  required: false
  default: 'true'
  tensorflow_version:
  description: The version of TensorFlow to install for any job that requires TensorFlow
  required: false
- default: 2.16.0
+ default: '2.16.0'
  install_pytorch:
  description: Indicate if PyTorch should be installed or not
  required: false
  default: 'true'
  pytorch_version:
  description: The version of PyTorch to install for any job that requires PyTorch
  required: false
- default: 2.3.0
+ default: '2.3.0'
  install_pennylane_lightning_master:
  description: Indicate if PennyLane-Lightning should be installed from the master branch
  required: false

.github/workflows/interface-unit-tests.yml

@@ -379,8 +379,7 @@ jobs:
  # catalyst requires the latest version of pennylane that is about to be released.
  # Installing catalyst after pennylane to make sure that the latest catalyst is used.
  install_catalyst_nightly: true
- # using lightning master does not work for the tests with external libraries
- install_pennylane_lightning_master: false
+ install_pennylane_lightning_master: true
  pytest_coverage_flags: ${{ inputs.pytest_coverage_flags }}
  pytest_markers: external
  additional_pip_packages: pyzx matplotlib stim quimb mitiq pennylane-qiskit ply

.github/workflows/tests-gpu.yml

@@ -15,7 +15,7 @@ concurrency:
  cancel-in-progress: true
 
 env:
- TORCH_VERSION: 2.2.0
+ TORCH_VERSION: 2.3.0
 
 jobs:
  gpu-tests:

.gitignore

@@ -27,3 +27,5 @@ config.toml
 qml_debug.log
 datasets/*
 .benchmarks/*
+*.h5
+*.hdf5

Makefile

@@ -60,12 +60,10 @@ clean-docs:
 
 test:
  $(PYTHON) $(TESTRUNNER)
- $(PYTHON) $(PLUGIN_TESTRUNNER) --device=default.qubit.autograd
 
 coverage:
  @echo "Generating coverage report..."
  $(PYTHON) $(TESTRUNNER) $(COVERAGE)
- $(PYTHON) $(PLUGIN_TESTRUNNER) --device=default.qubit.autograd $(COVERAGE) --cov-append
 
 .PHONY:format
 format:

doc/development/deprecations.rst

@@ -9,17 +9,18 @@ deprecations are listed below.
 Pending deprecations
 --------------------
 
-* All of the legacy devices (any with the name ``default.qubit.{autograd,torch,tf,jax,legacy}``) are deprecated. Use ``default.qubit`` instead,
- as it supports backpropagation for the many backends the legacy devices support.
+* ``Device``, ``QubitDevice``, and ``QutritDevice`` will no longer be imported top level in v0.40. They instead
+ we be available as ``qml.devices.LegacyDevice``, ``qml.devices.QubitDevice``, and ``qml.devices.QutritDevice``
+ respectively.
 
- - Deprecated in v0.38
- - Will be removed in v0.39
+ - Deprecated top level access in v0.39
+ - Top level access removed in v0.40
 
-* The logic for internally switching a device for a different backpropagation
- compatible device is now deprecated, as it was in place for the deprecated ``default.qubit.legacy``.
+* `QNode.gradient_fn` is deprecated. Please use `QNode.diff_method` instead. `QNode.get_gradient_fn` can also be used to
+ process the diff method.
 
- - Deprecated in v0.38
- - Will be removed in v0.39 
+ - Deprecated in v0.39
+ - Will be removed in v0.40
 
 * The ``decomp_depth`` argument in ``qml.device`` is deprecated. 
 
@@ -88,6 +89,23 @@ Other deprecations
 Completed deprecation cycles
 ----------------------------
 
+* All of the legacy devices (any with the name ``default.qubit.{autograd,torch,tf,jax,legacy}``) are removed. Use ``default.qubit`` instead,
+ as it supports backpropagation for the many backends the legacy devices support.
+
+ - Deprecated in v0.38
+ - Removed in v0.39
+
+* The logic for internally switching a device for a different backpropagation
+ compatible device is removed, as it was in place for removed ``default.qubit.legacy``.
+
+ - Deprecated in v0.38
+ - Removed in v0.39
+
+* `Operator.expand` is now removed. Use `qml.tape.QuantumScript(op.deocomposition())` instead.
+
+ - Deprecated in v0.38
+ - Removed in v0.39
+
 * The ``expansion_strategy`` attribute of ``qml.QNode`` is removed.
  Users should make use of ``qml.workflow.construct_batch``, should they require fine control over the output tape(s).
 

doc/development/guide/logging.rst

@@ -298,7 +298,7 @@ process, and surrounding operations:
 
  # Get logger for use by this script only.
  logger = logging.getLogger(__name__)
- dev_name = "default.qubit.jax"
+ dev_name = "default.qubit"
  num_wires = 2
  num_shots = None
 

doc/development/release_notes.md

@@ -5,6 +5,8 @@ This page contains the release notes for PennyLane.
 
 .. mdinclude:: ../releases/changelog-dev.md
 
+.. mdinclude:: ../releases/changelog-0.38.1.md
+
 .. mdinclude:: ../releases/changelog-0.38.0.md
 
 .. mdinclude:: ../releases/changelog-0.37.0.md

doc/introduction/interfaces/jax.rst

@@ -54,7 +54,7 @@ a JAX-capable QNode in PennyLane. Simply specify the ``interface='jax'`` keyword
 
 .. code-block:: python
 
- dev = qml.device('default.qubit.jax', wires=2)
+ dev = qml.device('default.qubit', wires=2)
 
  @qml.qnode(dev, interface='jax')
  def circuit1(phi, theta):
@@ -85,7 +85,7 @@ For example:
 
 .. code-block:: python
 
- dev = qml.device('default.qubit.jax', wires=2)
+ dev = qml.device('default.qubit', wires=2)
 
  @qml.qnode(dev, interface='jax')
  def circuit3(phi, theta):
@@ -119,7 +119,7 @@ the ``@jax.jit`` decorator can be directly applied to the QNode.
 
 .. code-block:: python
 
- dev = qml.device('default.qubit.jax', wires=2)
+ dev = qml.device('default.qubit', wires=2)
 
  @jax.jit # QNode calls will now be jitted, and should run faster.
  @qml.qnode(dev, interface='jax')
@@ -176,7 +176,7 @@ Example:
 
  # Device construction should happen inside a `jax.jit` decorated
  # method when using a PRNGKey.
- dev = qml.device('default.qubit.jax', wires=2, prng_key=key, shots=100)
+ dev = qml.device('default.qubit', wires=2, prng_key=key, shots=100)
 
 
  @qml.qnode(dev, interface='jax', diff_method=None)

doc/releases/changelog-0.38.0.md

@@ -1,6 +1,6 @@
 :orphan:
 
-# Release 0.38.0 (current release)
+# Release 0.38.0
 
 <h3>New features since last release</h3>
 

doc/releases/changelog-0.38.1.md

@@ -0,0 +1,14 @@
+:orphan:
+
+# Release 0.38.1 (current release)
+
+<h3>Bug fixes 🐛</h3>
+
+* Fix float-to-complex casting in various places across PennyLane.
+ [(#6260)](https://github.com/PennyLaneAI/pennylane/pull/6260)
+
+<h3>Contributors ✍️</h3>
+
+This release contains contributions from (in alphabetical order):
+
+Mudit Pandey

doc/releases/changelog-dev.md

@@ -5,16 +5,30 @@
 <h3>New features since last release</h3>
 
 <h3>Improvements 🛠</h3>
+
+* PennyLane is now compatible with NumPy 2.0.
+ [(#6061)](https://github.com/PennyLaneAI/pennylane/pull/6061)
+ [(#6258)](https://github.com/PennyLaneAI/pennylane/pull/6258)
+
+* `qml.qchem.excitations` now optionally returns fermionic operators.
+ [(#6171)](https://github.com/PennyLaneAI/pennylane/pull/6171)
+
 * The `diagonalize_measurements` transform now uses a more efficient method of diagonalization 
  when possible, based on the `pauli_rep` of the relevant observables.
  [#6113](https://github.com/PennyLaneAI/pennylane/pull/6113/)
 
+* The `Hermitian` operator now has a `compute_sparse_matrix` implementation.
+ [(#6225)](https://github.com/PennyLaneAI/pennylane/pull/6225)
+
 <h4>Capturing and representing hybrid programs</h4>
 
-* Differentiation of hybrid programs via `qml.grad` can now be captured into plxpr.
- When evaluating a captured `qml.grad` instruction, it will dispatch to `jax.grad`,
- which differs from the Autograd implementation of `qml.grad` itself.
+* Differentiation of hybrid programs via `qml.grad` and `qml.jacobian` can now be captured
+ into plxpr. When evaluating a captured `qml.grad` (`qml.jacobian`) instruction, it will
+ dispatch to `jax.grad` (`jax.jacobian`), which differs from the Autograd implementation
+ without capture. Pytree inputs and outputs are supported.
  [(#6120)](https://github.com/PennyLaneAI/pennylane/pull/6120)
+ [(#6127)](https://github.com/PennyLaneAI/pennylane/pull/6127)
+ [(#6134)](https://github.com/PennyLaneAI/pennylane/pull/6134)
 
 * Improve unit testing for capturing of nested control flows.
  [(#6111)](https://github.com/PennyLaneAI/pennylane/pull/6111)
@@ -23,6 +37,9 @@
  `from pennylane.capture.primitives import *`.
  [(#6129)](https://github.com/PennyLaneAI/pennylane/pull/6129)
 
+* `FermiWord` and `FermiSentence` classes now have methods to compute adjoints.
+ [(#6166)](https://github.com/PennyLaneAI/pennylane/pull/6166)
+
 * The `SampleMP.process_samples` method is updated to support using JAX tracers
  for samples, allowing compatiblity with Catalyst workflows.
  [(#6211)](https://github.com/PennyLaneAI/pennylane/pull/6211)
@@ -34,14 +51,24 @@
  unique representation of the object.
  [(#6167)](https://github.com/PennyLaneAI/pennylane/pull/6167)
 
+* A `ReferenceQubit` is introduced for testing purposes and as a reference for future plugin development.
+ [(#6181)](https://github.com/PennyLaneAI/pennylane/pull/6181)
+
+* The `to_mat` methods for `FermiWord` and `FermiSentence` now optionally return
+ a sparse matrix.
+ [(#6173)](https://github.com/PennyLaneAI/pennylane/pull/6173)
 
 <h3>Breaking changes 💔</h3>
 
 * Remove support for Python 3.9.
  [(#6223)](https://github.com/PennyLaneAI/pennylane/pull/6223)
 
-* `DefaultQubitTF` is removed. Please use `default.qubit` for all interfaces.
+* `DefaultQubitTF`, `DefaultQubitTorch`, `DefaultQubitJax`, and `DefaultQubitAutograd` are removed.
+ Please use `default.qubit` for all interfaces.
  [(#6207)](https://github.com/PennyLaneAI/pennylane/pull/6207)
+ [(#6208)](https://github.com/PennyLaneAI/pennylane/pull/6208)
+ [(#6209)](https://github.com/PennyLaneAI/pennylane/pull/6209)
+ [(#6210)](https://github.com/PennyLaneAI/pennylane/pull/6210)
 
 * `expand_fn`, `max_expansion`, `override_shots`, and `device_batch_transform` are removed from the
  signature of `qml.execute`.
@@ -57,16 +84,31 @@
  Please use `qml.transforms.split_non_commuting` instead.
  [(#6204)](https://github.com/PennyLaneAI/pennylane/pull/6204)
 
+* `Operator.expand` is now removed. Use `qml.tape.QuantumScript(op.deocomposition())` instead.
+ [(#6227)](https://github.com/PennyLaneAI/pennylane/pull/6227)
+
+
 <h3>Deprecations 👋</h3>
 
 * The ``QubitStateVector`` template is deprecated.
  Instead, use ``StatePrep``.
  [(#6172)](https://github.com/PennyLaneAI/pennylane/pull/6172)
 
+* `Device`, `QubitDevice`, and `QutritDevice` will no longer be accessible via top-level import in v0.40.
+ They will still be accessible as `qml.devices.LegacyDevice`, `qml.devices.QubitDevice`, and `qml.devices.QutritDevice`
+ respectively.
+ [(#6238)](https://github.com/PennyLaneAI/pennylane/pull/6238/)
+
+* `QNode.gradient_fn` is deprecated. Please use `QNode.diff_method` and `QNode.get_gradient_fn` instead.
+ [(#6244)](https://github.com/PennyLaneAI/pennylane/pull/6244)
+
 <h3>Documentation 📝</h3>
 
 <h3>Bug fixes 🐛</h3>
 
+* Fix a bug where zero-valued JVPs were calculated wrongly in the presence of shot vectors.
+ [(#6219)](https://github.com/PennyLaneAI/pennylane/pull/6219)
+
 * Fix `qml.PrepSelPrep` template to work with `torch`:
  [(#6191)](https://github.com/PennyLaneAI/pennylane/pull/6191)
 
@@ -75,14 +117,29 @@
 
 * The ``qml.QSVT`` template now orders the ``projector`` wires first and the ``UA`` wires second, which is the expected order of the decomposition.
  [(#6212)](https://github.com/PennyLaneAI/pennylane/pull/6212)
+
+* The ``qml.Qubitization`` template now orders the ``control`` wires first and the ``hamiltonian`` wires second, which is the expected according to other templates.
+ [(#6229)](https://github.com/PennyLaneAI/pennylane/pull/6229)
+
+* The ``qml.FABLE`` template now returns the correct value when JIT is enabled.
+ [(#6263)](https://github.com/PennyLaneAI/pennylane/pull/6263)
+
+* Fixes a bug where a circuit using the `autograd` interface sometimes returns nested values that are not of the `autograd` interface.
+ [(#6225)](https://github.com/PennyLaneAI/pennylane/pull/6225)
+
+* Fixes a bug where a simple circuit with no parameters or only builtin/numpy arrays as parameters returns autograd tensors.
+ [(#6225)](https://github.com/PennyLaneAI/pennylane/pull/6225)
 
-* <h3>Contributors ✍️</h3>
+<h3>Contributors ✍️</h3>
 
 This release contains contributions from (in alphabetical order):
 
 Guillermo Alonso,
 Utkarsh Azad,
+Astral Cai,
 Lillian M. A. Frederiksen,
+Pietropaolo Frisoni,
+Emiliano Godinez,
 Christina Lee,
 William Maxwell,
 Lee J. O'Riordan,

pennylane/__init__.py

@@ -16,8 +16,6 @@
 PennyLane can be directly imported.
 """
 
-import numpy as _np
-
 
 from pennylane.boolean_fn import BooleanFn
 import pennylane.numpy
@@ -180,13 +178,30 @@ def __getattr__(name):
  if name == "plugin_devices":
  return pennylane.devices.device_constructor.plugin_devices
 
+ from warnings import warn # pylint: disable=import-outside-toplevel
+
  if name == "QubitDevice":
+ warn(
+ "QubitDevice will no longer be accessible top level. Please access "
+ " the class as pennylane.devices.QubitDevice",
+ PennyLaneDeprecationWarning,
+ )
  return pennylane.devices._qubit_device.QubitDevice # pylint:disable=protected-access
 
  if name == "QutritDevice":
+ warn(
+ "QutritDevice will no longer be accessible top level. Please access "
+ " the class as pennylane.devices.QutritDevice",
+ PennyLaneDeprecationWarning,
+ )
  return pennylane.devices._qutrit_device.QutritDevice # pylint:disable=protected-access
 
  if name == "Device":
+ warn(
+ "Device will no longer be accessible top level. Please access "
+ " the class as pennylane.devices.LegacyDevice",
+ PennyLaneDeprecationWarning,
+ )
  return pennylane.devices._legacy_device.Device # pylint:disable=protected-access
 
  raise AttributeError(f"module 'pennylane' has no attribute '{name}'")