pytket-pennylane 0.21.0

Pytket extension and Pennylane plugin.

pytket-pennylane

Pytket is a python module for interfacing with tket, a quantum computing toolkit and optimising compiler developed by Quantinuum.

pytket-pennylane is an extension to pytket that allows pytket circuits to converted to pennylane.

See the PennyLane documentation to get an intro to PennyLane.

Some useful links:

• API Documentation

Getting started

pytket-pennylane is compatible with Python versions 3.11 to 3.13 on Linux, MacOS and Windows. To install, run:

pip install pytket-pennylane

This will install pytket if it isn't already installed, and add new classes and methods into the pytket.extensions namespace.

How to use

To use the integration once installed, initialise your pytket backend (in this example, an AerBackend which uses Qiskit Aer), and construct a PennyLane PytketDevice using this backend:

import pennylane as qml
from pytket.extensions.qiskit import AerBackend

# initialise pytket backend
pytket_backend = AerBackend()

# construct PennyLane device
dev = qml.device(
    "pytket.pytketdevice",
    wires=2,
    pytket_backend=pytket_backend,
    shots=1000
)

# define a PennyLane Qnode with this device
@qml.qnode(dev)
def my_quantum_function(x, y):
    qml.RZ(x, wires=0)
    qml.RX(y, wires=1)
    return qml.expval(qml.PauliZ(0) @ qml.PauliZ(1))

# call the node
print(my_quantum_function(0.1, 0.2))

The example above uses the Pytket default compilation pass for the backend, you can change the optimisation level of the default backend pass (0, 1 or 2) by setting the optimisation_level parameter:

dev = qml.device(
    "pytket.pytketdevice",
    wires=2,
    pytket_backend=pytket_backend,
    optimisation_level=2,
    shots=1000
)

You can also use any Pytket compilation pass using the compilation_pass parameter, which is used instead of the default pass:

from pytket.passes import PauliSimp, SequencePass

# use a Chemistry optimised pass before the backend's default pass

custom_pass = SequencePass([PauliSimp(), pytket_backend.default_compilation_pass()])

dev = qml.device(
    "pytket.pytketdevice",
    wires=2,
    pytket_backend=pytket_backend,
    compilation_pass=custom_pass,
    shots=1000
)

Bugs, support and feature requests

Please file bugs and feature requests on the Github issue tracker.

Development

To install an extension in editable mode run:

pip install -e .

We have set up the repo to be used with uv. You can use also:

uv sync --python 3.12

to install the package. This will automatically pick up all requirements for the tests as well.

Contributing

Pull requests are welcome. To make a PR, first fork the repo, make your proposed changes on the main branch, and open a PR from your fork. If it passes tests and is accepted after review, it will be merged in.

Code style

Formatting

All code should be formatted using ruff, with default options. This is checked on the CI.

Type annotation

On the CI, mypy is used as a static type checker and all submissions must pass its checks. You should therefore run mypy locally on any changed files before submitting a PR. You can run them with:

uv run mypy --config-file=mypy.ini --no-incremental --explicit-package-bases pytket tests

Linting

We use ruff on the CI to check compliance with a set of style requirements (listed in ruff.toml). You should run ruff over any changed files before submitting a PR, to catch any issues.

An easy way to meet all formatting and linting requirements is to issue pre-commit run --all-files.

If you are using uv running uv run pre-commit run --all-files --show-diff-on-failure will install the package and run all the checks.

Tests

To run the tests for this module:

1. ensure you have installed pytest, hypothesis, and any modules listed in the dev-dependencies section of the pyproject.toml file; (If you are using uv this will be picked up automatically.)
2. run pytest.

When adding a new feature, please add a test for it. When fixing a bug, please add a test that demonstrates the fix.