devitt1/benchq

Resource estimation for fault-tolerant quantum computation.

benchq

What is it?

benchq estimates the required resources for performing a fault-tolerant computation using surface codes. It works with various inputs, such as circuits, openfermion QubitOperators, and pyscf files. Given correct input, benchq will return a list of resources required to perform the selected algorithm such as the required number of physical qubits, error rate, wall time, etc.

benchq was developed as a part of DARPA Quantum Benchmarking program.

Installation

To install benchq run pip install . from the main directory. It's been tested with Python 3.8-3.9 on macOS and Linux. Requires Jabalizer 0.4.3.

Known limitation: installation can fail because of a problem with pyscf, one of our transitive dependencies. If you're a Windows user, please consider using WSL. On other systems you can try installing pyscf directly from its git repo: pip install git+https://github.com/pyscf/[email protected].

Extra dependencies

Graph compilation requires non-Python dependencies to be installed. Either:

1. Install a recent Julia version from the Julia website.
2. Make sure julia executable is on your $PATH. You can test it by running julia in a new terminal window.
3. Install Julia dependencies: open julia REPL, press ], run add Jabalizer.

Or:

1. Run python setup_julia.py in repo root.

If you plan to use PySCF to generate Hamiltonians, use the pyscf install extra:

pip install '.[pyscf]'

To run resource estimation using Azure Quantum Resource Estimation (QRE) tool, one needs to have Azure QRE package configured, please see this tutorial.

Usage

Please take a look at the examples directory. We have multiple examples there:

• h_chain_trotter.py shows how to use graph state compilation on a simple hydrogen chain example. (Requires pyscf install extra.)
• resource_estimate_from_qasm.py shows how to use graph state compilation when the circuit is loaded from QASM.
• qsp_vlasov.py shows how to perform resource estimation.

Running benchmarks

To run the benchmarks run

pytest benchmarks/

from the top-level directory of this repo. By default, this will skip some benchmarks that run extremely low. If you want to run those too, set environmental variable SLOW_BENCHMARKS to any value, e.g.:

SLOW_BENCHMARKS=1 pytest benchmarks/

Development and Contribution

To install the development version, run pip install -e '.[dev]' from the main directory. (if using MacOS, you will need single quotes around the []. If using windows, or Linux, you might not need the quotes).

We use Google-style docstring format. If you'd like to specify types please use PEP 484 type hints instead adding them to docstrings.

There are codestyle-related Github Actions running for PRs. (TODO)

• If you'd like to report a bug/issue please create a new issue in this repository.
• If you'd like to contribute, please create a pull request to main.

Running tests

Unit tests for this project can be run using make coverage command from the main directory. Alternatively you can also run pytest ..

Since tests of integration with Azure QRE require additional setup, they are disabled by default. You can enable them by setting environmental variable BENCHQ_TEST_AZURE to any value.

Style

We are using automatic tools for style and type checking. In order to make sure the code is compliant with them please run: make style from the main directory (this requires dev dependencies).