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Slycot: a wrapper for the SLICOT control and systems library

## Project description

Python wrapper for selected SLICOT routines, notably including solvers for Riccati, Lyapunov, and Sylvester equations.

## Dependencies

Slycot supports Python versions 2.7 and >=3.5.

To run the compiled Slycot package, the following must be installed as dependencies:

• Python 2.7, 3.5+
• NumPy

If you are compiling and installing Slycot from source, you will need the following dependencies:

• Python 2.7, 3.5+
• NumPy
• scikit-build >=0.8.1
• cmake
• C compiler (e.g. gcc, MS Visual C++)
• FORTRAN compiler (e.g. gfortran, ifort, flang)
• BLAS/LAPACK (e.g. OpenBLAS, ATLAS, MKL)

There are a variety of ways to install these dependencies on different operating systems. See the individual packages’ documentation for options.

## Installing

In general Slycot requires non-trivial compilation to install on a given system. The easiest way to get started using Slycot is by installing pre-compiled binaries. The Slycot team provides pre-compiled binaries via the conda package manager and conda forge package hosting channel for Linux, OSX, and Windows.

### Using conda

Install Miniconda or Anaconda and then Slycot can be installed via the conda package manager from the conda-forge channel with the following command:

conda install -c conda-forge slycot


### Using pip

Slycot can also be installed via the pip package manager. Install pip as per recommendations in pip’s documentation. At a minimum, Python and pip must be installed. If a pre-complied binary (i.e. “wheel”) is available it will be installed with no need for compilation. If not, pip will attempt to compile the package from source and thus the compilation dependencies will be required (scikit-build, gfortran, BLAS, etc.).

Pip can then be used to install Slycot with the command:

pip install slycot


### From source

Unpack the course code to a directory of your choice, e.g. /path/to/slycot_src/

If you need to specify a specific compiler, set the environment variable FC before running the install:

# Linux/OSX:
export FC=/path/to/my/fortran

# Windows:
set FC=D:\path\to\my\fortran.exe


To build and install execute:

cd /path/to/slycot_src/
python setup.py install


You can also use conda to build and install Slycot from source:

conda build conda-recipe
conda install --use-local slycot


If you prefer to use the OpenBLAS library, a conda recipe is available in conda-recipe-openblas.

Additional tips for how to install Slycot from source can be found in the .travis.yml (commands used for Travis CI) and conda-recipe/ (conda pre-requisites) both which are included in the source code repository.

The hardest part about installing from source is getting a working version of FORTRAN and LAPACK installed on your system and working properly with Python. On Windows, the build system currently uses flang, which can be installed from conda-forge. Note that flang is incompatible with Python 2.7.

If you are using conda, you can also get working (binary) copies of LAPACK from conda-forge using the command:

conda install -c conda-forge lapack


Slycot will also work with the OpenBLAS libraries.

Note that in some cases you may need to set the LIBRARY_PATH environment variable to pick up dependencies such as -lpythonN.m (where N.m is the version of python you are using).