# [QuEST](https://quest.qtechtheory.org) [](https://github.com/QuEST-Kit/QuEST/actions) [](https://github.com/QuEST-Kit/QuEST/actions) [](https://github.com/QuEST-Kit/QuEST/actions) ## Introduction The **Quantum Exact Simulation Toolkit** is a high performance simulator of universal quantum circuits, state-vectors and density matrices. QuEST is written in C, hybridises OpenMP and MPI, and can run on a GPU. Needing only compilation, QuEST is easy to run both on laptops and supercomputers (in both C and C++), where it can take advantage of multicore, GPU-accelerated and networked machines to quickly simulate circuits on many qubits. QuEST has a simple interface, independent of its run environment (on CPUs, GPUs or over networks), ```C hadamard(qubits, 0); controlledNot(qubits, 0, 1); rotateY(qubits, 0, .1); ``` though is flexible ```C Vector v; v.x = 1; v.y = .5; v.z = 0; rotateAroundAxis(qubits, 0, 3.14/2, v); ``` and powerful ```C // sqrt(X) with pi/4 global phase ComplexMatrix2 u = { .real = {{.5, .5}, { .5,.5}}, .imag = {{.5,-.5}, {-.5,.5}}}; unitary(qubits, 0, u); int controls[] = {1, 2, 3, 4, 5}; multiControlledUnitary(qureg, controls, 5, 0, u); ``` QuEST can simulate decoherence on mixed states, output [QASM](https://arxiv.org/abs/1707.03429), perform measurements, apply general unitaries with any number of control and target qubits, and boasts cheap/fast access to the underlying numerical representation of the state. QuEST offers precision-agnostic real and imaginary (additionally include `QuEST_complex.h`) number types, the precision of which can be modified at compile-time, as can the target hardware. Learn more about QuEST at [quest.qtechtheory.org](https://quest.qtechtheory.org), or read the [whitepaper](https://www.nature.com/articles/s41598-019-47174-9). If you find QuEST useful, feel free to cite ``` Jones, T., Brown, A., Bush, I. et al. QuEST and High Performance Simulation of Quantum Computers. Sci Rep 9, 10736 (2019) doi:10.1038/s41598-019-47174-9 ``` ``` @article{Jones2019, title={{QuEST} and high performance simulation of quantum computers}, author={Jones, Tyson and Brown, Anna and Bush, Ian and Benjamin, Simon C}, journal={Scientific reports}, volume={9}, number={1}, pages={1--11}, year={2019}, publisher={Nature Publishing Group} } ``` --------------------------------- ## Documentation Full documentation is available at [quest.qtechtheory.org/docs](https://quest.qtechtheory.org/docs/), and the API is available [here](https://quest-kit.github.io/QuEST/modules.html) (all functions listed [here](https://quest-kit.github.io/QuEST/QuEST_8h.html)). See also the [tutorial](/examples/README.md). > **For developers**: To regenerate the API doc after making changes to the code, run `doxygen doxyconfig/config` in the root directory. This will generate documentation in `Doxygen_doc/html`, the contents of which should be copied into [`docs/`](/docs/)). Make sure that `PROJECT_NUMBER` in `doxyconfig/config` is up to date! --------------------------------- ## Getting started QuEST is contained entirely in the files in the `QuEST/` folder. To use QuEST, copy this folder to your computer and include `QuEST.h` in your `C` or `C++` code, and compile using cmake with the provided [CMakeLists.txt file](/CMakeLists.txt). See the [tutorial](/examples/README.md) for an introduction. We also include example [submission scripts](examples/submissionScripts/) for using QuEST with SLURM and PBS. ### Quick Start #### MacOS & Linux MacOS and Linux users can clone this repository to your machine through the terminal: ```bash git clone https://github.com/quest-kit/QuEST.git cd QuEST ``` Compile the [example](examples/tutorial_example.c) using ```bash mkdir build cd build cmake .. make ``` then run it with ```bash ./demo ``` #### Windows Windows users should install [Build Tools](https://visualstudio.microsoft.com/downloads/#build-tools-for-visual-studio-2019) for Visual Studio, [CMake](https://cmake.org/download/) and [MinGW-w64](https://sourceforge.net/projects/mingw-w64/). Then, in a *Developer Command Prompt for VS*, run ```bash git clone "https://github.com/quest-kit/QuEST.git" cd QuEST ``` ```bash mkdir build cd build cmake .. -G "MinGW Makefiles" make ``` ```bash demo.exe ``` #### Tests Additionally, you can run QuEST's rigorous unit tests in your own environment, which should take no longer than ten minutes. ```bash mkdir build cd build cmake .. -DTESTING=ON make make test ``` --------------------------------- ## Contact To file a bug report or feature request, [raise a github issue](https://github.com/QuEST-Kit/QuEST/issues). For additional support, email quest@materials.ox.ac.uk. You can view the list of contributors to QuEST in [`AUTHORS.txt`](AUTHORS.txt). --------------------------------- ## Acknowledgements QuEST uses the [mt19937ar](http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/emt19937ar.html) Mersenne Twister algorithm for random number generation, under the BSD licence. QuEST optionally (by additionally importing `QuEST_complex.h`) integrates the [language agnostic complex type](http://collaboration.cmc.ec.gc.ca/science/rpn/biblio/ddj/Website/articles/CUJ/2003/0303/cuj0303meyers/index.htm) by Randy Meyers and Dr. Thomas Plum Thanks to [HQS Quantum simulations](https://quantumsimulations.de/) for contributing the `mixDamping` function. --------------------------------- ## Licence QuEST is released under a [MIT Licence](LICENCE.txt) --------------------------------- ## Related projects -- QuEST utilities and extensions * [PyQuEST-cffi](https://github.com/HQSquantumsimulations/PyQuEST-cffi): a python interface to QuEST based on cffi developed by HQS Quantum Simulations. Please note, PyQuEST-cffi is currently in the alpha stage and not an official QuEST project. * [QuESTlink](https://questlink.qtechtheory.org): a Mathematica package allowing symbolic circuit manipulation and high performance simulation with remote accelerated hardware.