Installing pysteps#

Dependencies#

The pysteps package needs the following dependencies

Additionally, the following packages can be installed for better computational efficiency:

  • dask and toolz (for code parallelization)

  • pyfftw (for faster FFT computation)

Other optional dependencies include:

Important: If you only want to use pysteps, you can continue reading below. But, if you want to contribute to pysteps or edit the package, you need to install pysteps in development mode: Contributing to pysteps.

Install from source#

The recommended way to install pysteps from the source is using pip to adhere to the PEP517 standards. Using pip instead of setup.py guarantees that all the package dependencies are properly handled during the installation process.

OSX users: gcc compiler#

pySTEPS uses Cython extensions that need to be compiled with multi-threading support enabled. The default Apple Clang compiler does not support OpenMP. Hence, using the default compiler would have disabled multi-threading and may raise the following error during the installation:

clang: error: unsupported option '-fopenmp'
error: command 'gcc' failed with exit status 1

To solve this issue, obtain the latest gcc version with Homebrew that has multi-threading enabled:

brew install gcc

To make sure that the installer uses the homebrew’s gcc, export the following environmental variables in the terminal (supposing that gcc version 8 was installed):

export CC=gcc-13
export CXX=g++-13

First, check that the homebrew’s gcc is detected:

which gcc-13

This should point to the homebrew’s gcc installation.

Under certain circumstances, Homebrew does not add the symbolic links for the gcc executables under /usr/local/bin. If that is the case, specify the CC and CCX variables using the full path to the homebrew installation. For example:

export CC=/usr/local/Cellar/gcc/13.2.0/bin/gcc-13
export CXX=/usr/local/Cellar/gcc/13.2.0/bin/g++-13

Then, you can continue with the normal installation procedure described next.

Installation using pip#

The latest pysteps version in the repository can be installed using pip by simply running in a terminal:

pip install git+https://github.com/pySTEPS/pysteps

Or, from a local copy of the repo:

git clone https://github.com/pySTEPS/pysteps
cd pysteps
pip install .

The above commands install the latest version of the master branch, which is continuously under development.

Warning

If you are installing pysteps from the sources using pip, the Python interpreter must be launched outside of the pysteps root directory. Importing pysteps from a working directory that contains the pysteps source code will raise a ModuleNotFoundError. This error is caused by the root pysteps folder being recognized as the pysteps package, also known as the double import trap.

Setting up the user-defined configuration file#

The pysteps package allows the users to customize the default settings and configuration. The configuration parameters used by default are loaded from a user-defined JSON file and then stored in the pysteps.rcparams, a dictionary-like object that can be accessed as attributes or as items.

Final test: import pysteps in Python#

Activate the pysteps environment:

conda activate pysteps

Launch Python and import pysteps:

python
>>> import pysteps