Installation

Installing GEHONG

To install GEHONG, simply use:

pip install csst-ifs-gehong

This installs the core Python package. However, spectral templates required for modeling are not included and must be downloaded separately, as described below.

Downloading Spectral Templates

GEHONG relies on external datasets for stellar and emission line spectral modeling. These templates are not bundled in the PyPI package and must be downloaded from GitHub.

You can clone the official data repository here:

Clone it using:

git clone https://github.com/fengshuai0210/csst-ifs-gehong-data.git

This will produce a folder structure like:

csst-ifs-gehong-data/
└── data/

Setting the Resource Path

GEHONG requires access to external resource files (e.g., SSP templates, emission line data), located in the data/ folder of the downloaded data repository.

You can configure the resource path using any one of the following three methods:

  1. Set an environment variable (recommended for persistent use)

    Add the following line to your shell configuration file (e.g., ~/.bash_profile, ~/.zshrc, or ~/.bashrc):

    export gehong_path='/Users/sfeng/GIT/csst-ifs-gehong-data'

    Then reload the shell environment:

    source ~/.bash_profile  # or ~/.zshrc, ~/.bashrc, etc.

  2. Set the path at runtime in Python

    For temporary or interactive use, you can configure the path manually:

    import gehong
gehong.set_path("/Users/sfeng/GIT/csst-ifs-gehong-data")

  3. Use the development mode fallback

    If you’re developing GEHONG locally, you may place the data/ folder directly inside the gehong/ package directory. This fallback will be used automatically if no other path is specified.

All methods require that the target directory contains the expected subdirectory structure:

csst-ifs-gehong-data/
└── data/

Verifying Installation

To confirm that GEHONG is installed and configured correctly, you can run the following test script in Python:

import gehong
import os

# Check version
print("GEHONG version:", gehong.__version__)

# Get the configured resource path
try:
    path = gehong.get_path()
except RuntimeError as e:
    raise RuntimeError("Resource path is not set correctly:\n" + str(e))
else:
    print("GEHONG resource path =", path)

# Check if 'data/' subdirectory exists
expected_path = os.path.join(path, "data")
if not os.path.isdir(expected_path):
    raise FileNotFoundError(f"'data' folder not found at: {expected_path}")
else:
    print("Data folder found at:", expected_path)

If all checks pass without error, your installation and configuration are complete.

Next Steps

If everything is installed and configured correctly, you’re ready to start using GEHONG.

We recommend beginning with the following module-specific examples. These tutorials demonstrate how to configure parameters and generate synthetic spectra or maps for different physical components.

To get started with practical usage, refer to: