ffsim 0.0.27

Faster simulations of fermionic quantum circuits.

ffsim

Faster simulations of fermionic quantum circuits.

What is ffsim?

ffsim is a software library for simulating fermionic quantum circuits that conserve particle number and the Z component of spin. This category includes many quantum circuits used for quantum chemistry simulations. By exploiting the symmetries and using specialized algorithms, ffsim can simulate these circuits much faster than a generic quantum circuit simulator.

Experimental disclaimer: ffsim is currently an experimental release. Breaking changes may be introduced without warning.

Documentation

Documentation is located at the project website.

Supported platforms

ffsim is supported on Linux, macOS, and the Windows Subsystem for Linux (WSL). It is not supported on Windows.

Installation

From PyPI

ffsim is available on PyPI. It can be installed by running the command

pip install ffsim

From source

Installing ffsim from source requires the following system dependencies:

• A Rust compiler. See these instructions.
• A BLAS implementation.
  • On macOS, ffsim uses the Accelerate framework that is included with the operating system, so no action is required.
  • On Linux, ffsim uses OpenBLAS. You may be able to install it using your system package manager:

    • Arch Linux:

      sudo pacman -S blas-openblas
      

    • Fedora:

      sudo dnf install openblas-devel
      

    • Ubuntu:

      sudo apt install libopenblas-dev
      

Once these dependencies are satisfied, ffsim can be installed by running the command

pip install .

from the root directory of the code repository.

Development

Setup

To set up ffsim for development, install it from source in editable mode along with the development requirements:

pip install -e ".[dev]"

To install the git pre-commit hooks, run

pre-commit install

Rust

If you add or modify any Rust modules, rebuild them by running the command

maturin develop

If you are benchmarking the code, then pass the --release flag:

maturin develop --release

Run code checks using tox

You can run tests and other code checks using tox. To run all checks, simply run

tox

To run a specific check, run

tox run -e <environment name>

substituting <environment name> with the name of the tox environment for the check. The following environments are available:

• py38, py39, py310, py311, py312: Run tests for a specific Python version
• coverage: Code coverage
• type: Type check
• lint: Lint check
• format: Format check
• docs: Build documentation

Run code checks directly

Running the code checks directly using the corresponding software tool can be useful and allows you to:

• Automatically fix lint and formatting errors.
• Build the documentation without deleting cached files.

Run tests

pytest

Run type check

mypy

Fix lint errors

ruff check --fix

Fix formatting errors

ruff format

Build documentation

sphinx-build -b html -W docs/ docs/_build/html

View locally built documentation

After building the docs using either the tox command or the sphinx command, open the file docs/_build/html/index.html in your web browser. For rapid iterations, the sphinx command is preferred because it retains cached files. Building the documentation can consume significant CPU because the tutorial notebooks are executed. The tox command deletes cached files so it will execute all the notebooks every time, while the sphinx command only executes notebooks if they were modified from the previous run.

Cite ffsim

You can cite ffsim using the following BibTeX:

@software{ffsim,
  author = {{The ffsim developers}},
  title = {ffsim},
  url = {https://github.com/qiskit-community/ffsim}
}