A Python wrapper to the CUTEst optimization test environment

mathematics, optimization, optimization-tools
pip install pycutest==1.6.2


PyCUTEst: A Python interface to the CUTEst Optimization Test Environment GNU GPL v3 License PyPI version Total downloads JOSS Paper

PyCUTEst is a Python interface to CUTEst, a Fortran package for testing optimization software. It is based on the interface originally developed for CUTEr by Prof. Arpad Buermen.

Full details on how to use PyCUTEst are available in the documentation, and a brief summary of the package's goals is available in the PyCUTEst journal article.


PyCUTEst requires the following software to be installed:

Please Note: Currently PyCUTEst only supports Mac and Linux. For Windows 10 (or later), PyCUTEst can be used through the Windows Subsystem for Linux, following the Linux installation instructions.

Installing CUTEst on Linux

These instructions do not include installation of the MATLAB interface. You will need to install four packages: archdefs, SIFDecode, CUTEst and MASTSIF. To keep things simple, install all four packages in the same directory:

Note that mastsif contains all the test problem definitions and is therefore quite large. If you're short on space you may want to copy only the *.SIF files for the problems you wish to test on.

Next set the following environment variables in your ~/.bashrc to point to the installation directories used above:

Now we are ready to install CUTEst in double precision (requires gfortran and gcc):

And CUTEst should run from here. To test that the installation works, issue the commands:

Please Note: currently PyCUTEst only supports gfortran and uses the default version on your path (as returned by gfortran -v ). Please ensure this is the same version that you install CUTEst with above otherwise you may experience segmentation faults.

Installing CUTEst on Mac

Install CUTEst using Homebrew as detailed below (installing CUTEst manually on Mac is not supported). First it is important to ensure that you have the latest version of Xcode Command Line Tools installed (or the latest version of Xcode), please ensure this is the case by following this guide. Now install the Homebrew package manager:

Then you can easily install CUTEst:

Anaconda Users: please ensure that ~/.bashrc is sourced in your conda environment (you can do this with the command source ~/.bashrc ) otherwise you may encounter errors using PyCUTEst.

Please Note: you may see warnings such as ld: warning: object file (RANGE.o) was built for newer macOS version (11.5) than being linked (10.15) . To suppress these warnings please set the environment variable MACOSX_DEPLOYMENT_TARGET to your current macOS version (e.g. export MACOSX_DEPLOYMENT_TARGET=11.5 in this example, you can make this permanent by adding it to your ~/.bashrc file).

Installing PyCUTEst

For easy installation, use pip:

Note that if an older install of PyCUTEst is present on your system you can use:

to upgrade PyCUTEst to the latest version.

You will then need to create a folder which will store all your compiled problems:

And set an environment variable to tell PyCUTEst about this directory, by adding to your ~/.bashrc file:

If you do not set this environment variable, then PyCUTEst will create a cache folder of compiled problems inside your current working directory.

Note that you can uninstall PyCUTEst as follows:


Please ask any questions or report problems using GitHub's issue tracker.


Please report any bugs using GitHub's issue tracker.


To cite PyCUTEst, please use the following reference:

J. Fowkes, L. Roberts, and Á. Bűrmen, (2022). PyCUTEst: an open source Python package of optimization test problems. Journal of Open Source Software, 7(78), 4377,

In BibTeX, the citation is:

    doi = {10.21105/joss.04377},
    url = {},
    year = {2022},
    publisher = {The Open Journal},
    volume = {7},
    number = {78},
    pages = {4377},
    author = {Jaroslav Fowkes and Lindon Roberts and Árpád Bűrmen},
    title = {PyCUTEst: an open source Python package of optimization test problems},
    journal = {Journal of Open Source Software}


We welcome contributions to PyCUTEst, please see


This package is released under the GNU GPL license.