PennyLane qiskit Plugin
PennyLane is a cross-platform Python library for quantum machine learning, automatic differentiation, and optimization of hybrid quantum-classical computations.
qiskit is an open-source compilation framework capable of targeting various types of hardware and a high-performance quantum computer simulator with emulation capabilities, and various compiler plug-ins.
This PennyLane plugin allows to use both the software and hardware backends of qiskit as devices for PennyLane.
- Provides three devices to be used with PennyLane:
qiskit.ibmq. These devices provide access to the various backends.
- Supports a wide range of PennyLane operations and expectation values across the providers.
- Combine qiskit high performance simulator and hardware backend support with PennyLane's automatic differentiation and optimization.
This plugin requires Python version 3.5 and above, as well as PennyLane and qiskit. Installation of this plugin, as well as all dependencies, can be done using pip:
$ python -m pip install pennylane_qiskit
To test that the PennyLane qiskit plugin is working correctly you can run
$ make test
in the source folder. Tests restricted to a specific provider can be run by executing
make test-aer or
Tests on the IBMQ device can
only be run if a
ibmqx_token for the IBM Q experience is
configured in the PennyLane configuration file.
If this is the case, running
make test also executes tests on the
ibmq device. By default tests on
ibmq device run with
ibmq_qasm_simulator backend and those done by the
aer device are run with the
qasm_simulator backend. At the time of writing this means that the test are "free".
Please verify that this is also the case for your account.
You can instantiate a
'qiskit.aer' device for PennyLane with:
import pennylane as qml dev = qml.device('qiskit.aer', wires=2)
This device can then be used just like other devices for the definition and evaluation of QNodes within PennyLane. A simple quantum function that returns the expectation value of a measurement and depends on three classical input parameters would look like:
@qml.qnode(dev) def circuit(x, y, z): qml.RZ(z, wires=) qml.RY(y, wires=) qml.RX(x, wires=) qml.CNOT(wires=[0, 1]) return qml.expval.PauliZ(wires=1)
You can then execute the circuit like any other function to get the quantum mechanical expectation value.
circuit(0.2, 0.1, 0.3)
You can also change the default device's backend with
dev = qml.device('qiskit.aer', wires=2, backend='unitary_simulator')
To get a current overview what backends are available you can query this by
While the device
'qiskit.aer' is the standard go-to simulator that is provided along the qiskit main package
installation, there exists a natively included python simulator that is slower but will work usually without the need
to check out other dependencies (gcc, blas and so on) which can be sed by
There is an important difference of the two: while
'qiskit.aer' supports a simulation with noise
'qiskit.basicaer' does not.
You can instantiate a noise model and apply it to the device by calling
import pennylane as qml import qiskit from qiskit.providers.aer.noise.device import basic_device_noise_model qiskit.IBMQ.load_accounts() ibmqx4 = qiskit.IBMQ.get_backend('ibmqx4') device_properties = ibmqx4.properties() noise_model = basic_device_noise_model(device_properties) dev = qml.device('qiskit.aer', wires=2, noise_model=noise_model)
Then all simulations are done with noise. The basic noise model is explained a little at qiskit's documentation.
Finally one of the more interesting functionality is running your code through the IBM Quantum Experience API.
You can choose between different backends having either simulators or real hardware depending on your agreement with
To use this device you would instantiate a
'qiskit.ibmq' device by giving your IBM Quantum Experience token:
import pennylane as qml dev = qml.device('qiskit.ibmq', wires=2, ibmqx_token="XXX")
In order to avoid accidentally publishing your token, you should better specify it via the PennyLane configuration file by adding a section such as
[qiskit.global] [qiskit.ibmq] ibmqx_token = "XXX"
It is also possible to define an environment variable
IBMQX_TOKEN, from which the token will be taken if not provided in another way.
Per default the backend
ibmq uses the simulator backend
ibmq_qasm_simulator, but you can change that
to be any of the real backends as given by
How to cite
If you are doing research using PennyLane, please cite our whitepaper:
Ville Bergholm, Josh Izaac, Maria Schuld, Christian Gogolin, Carsten Blank, Keri McKiernan and Nathan Killoran. PennyLane. arXiv, 2018. arXiv:1811.04968
We welcome contributions - simply fork the repository of this plugin, and then make a pull request containing your contribution. All contributers to this plugin will be listed as authors on the releases.
We also encourage bug reports, suggestions for new features and enhancements, and even links to cool projects or applications built on PennyLane.
Carsten Blank, Sebastian Boerakker, Christian Gogolin, Josh Izaac
- Source Code: https://github.com/carstenblank/pennylane-qiskit
- Issue Tracker: https://github.com/carstenblank/pennylane-qiskit/issues
If you are having issues, please let us know by posting the issue on our Github issue tracker.
The PennyLane qiskit plugin is free and open source, released under the Apache License, Version 2.0.