How to activate the DESC software environment

The software environment developed and maintained by members of the LSST Dark Energy Science Collaboration (DESC) is installed under


You can activate the DESC environment with the command

source /pbs/throng/lsst/software/desc/common/miniconda/

This command initializes or extends some environment variables (e.g. PATH, PYTHONPATH, etc.) and activates a DESC-specific conda environment. If for your specific needs you want to extend that enviroment with additional packages, you may need to clone it (see Cloning a conda environment) in order to avoid permission denied errors resulting from the fact that the storage under /pbs/throng/lsst/software/desc is only writable by its maintainer. To instruct conda where to install your packages create or modify the file $HOME/.condarc so that it contains the path to a location where you have write privileges, for instance under /pbs/throng/lsst/users/<you>:

   - /pbs/throng/lsst/users/<you>/.conda/pkgs

If you need to use the DESC software environment from within your Jupyter notebooks, please refer to How to execute LSST-enabled JupyterLab notebooks.


Under some circumstances, activating the DESC software environment in a session where you have activated the LSST science pipelines may not work. If you observe unexpected behavior, try activating each of those environments in different shell sessions.

See also the Software section for information about other software available.