Requirements & Installation
Note
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Installing with pip
STPSF and its underlying optical library POPPY may be installed from the Python Package Index in the usual manner for Python packages.
$ pip install --upgrade stpsf
[... progress report ...]
Successfully installed stpsf
Installing or updating synphot
Stsynphot is an optional dependency, but is highly recommended. Its installation instructions can be found in the synphot docs or a discussion in the POPPY docs.
Installing the Required Data Files
Note
The necessary data files will be installed automatically in a default path, $HOME/data/stpsf-data, and there is no user action required unless you want to install them somewhere else.
Files containing such information as the JWST pupil shape, instrument throughputs, and aperture positions are distributed separately from STPSF. These sum to about 100 MB in size.
STPSF will now automatically download and install these files the first time it is run. By default these will be downloaded and installed into a folder $HOME/data/stpsf-data within the user’s home directory. This directory will be created automatically if it doesn’t exist already. If this path is acceptable to you, then no further action is needed on your part, and it’ll all work automatically.
If you would like to place the data files at some other location, you can manually install the data files yourself.
Download the following file: stpsf-data-LATEST.tar.gz [approx. 175 MB]
Untar
stpsf-data-LATEST.tar.gzinto a directory of your choosing.Set the environment variable
STPSF_PATHto point to that directory. e.g.export STPSF_PATH=$HOME/data/stpsf-data
for bash. (You will probably want to add this to your .bashrc, or equivalent for the shell of your choice.)
You should now be able to successfully import stpsf in a Python session.
Warning
If you have previously installed the data files for an earlier version of STPSF, and then update to a newer version, the software may prompt you that you must download and install a new updated version of the data files.
Note
For STScI Users Only: Users at STScI may access the required data files from the Central Storage network. Set the following environment variables in your bash shell. (You will probably want to add this to your .bashrc.)
export STPSF_PATH="/grp/stpsf/stpsf-data"
export PYSYN_CDBS="/grp/hst/cdbs"
Software Requirements
See the requirements.txt specification file for the required package dependencies.
Required Python version: STPSF 1.1 and above require Python 3.10 or higher.
The major dependencies are the standard NumPy, SciPy, matplotlib stack, and Astropy.
Recommended Python packages:
synphot enables the simulation of PSFs with proper spectral response to realistic source spectra. Without this, PSF fidelity is reduced. See above for installation instructions for synphot. Stsynphot is recommended for most users.
Optional Python packages:
Some calculations with POPPY can benefit from the optional packages psutil and pyFFTW, but these are not needed in general. See the POPPY installation docs for more details. These optional packages are only worth adding for speed improvements if you are spending substantial time running calculations.
Additional packages are needed for the optional use of GPUs to accelerate calculations. See the POPPY documentation.
Installing a pre-release version or contributing to STPSF development
The STPSF source code repository is hosted at GitHub, as is the repository for POPPY. Users may clone or fork in the usual manner. Pull requests with code enhancements welcomed.
To install the current development version of STPSF, you can use pip to install directly from a git repository. To install STPSF and POPPY from git, uninstall any existing copies of STPSF and POPPY, then invoke pip as follows:
$ pip install -e git+https://github.com/spacetelescope/poppy.git#egg=poppy \
-e git+https://github.com/spacetelescope/stpsf.git#egg=stpsf
This will create directories ./src/poppy and ./src/stpsf in your current directory containing the cloned repository. If you have commit access to the repository, you may want to clone via ssh with a URL like git+ssh://git@github.com:spacetelescope/stpsf.git. Documentation of the available options for installing directly from Git can be found in the pip documentation.
Remember to install the required data files, if you have not already installed them.
Using Specific Data Versions
If you need a specific version of the STPSF data you can download it directly