Follow these steps to successfully install Trident and its dependencies.

Versions of Trident

There are currently two versions of Trident: a stable version and a development version. Make sure you are reading the correct docs for the version you are using!

The stable version is tried and tested and easy to install with pip. The development version is actively being updated with new features. Note that the stable version of trident requires the stable version of yt, and the development version of trident requires the development version of yt.

Thus, the installation steps are slightly different for stable and development, so pay attention in the steps below. Don’t worry if you want to change later, you can always switch between the two versions easily enough by following the directions in Uninstallation or Switching Code Versions.

Trident’s Major Dependency: yt

yt is a python-based software package for the analysis and visualization of a different numerical datasets, including astrophysical hydrodynamical data. yt is the primary dependency of Trident, so it must be present for Trident to work. There are several methods for installing yt, which are all discussed in detail in the yt installation documentation. Use the one that is appropriate for you. We find that using conda is the most streamlined and reliable for the development install, whereas pip does it automatically for stable install.

Installing the Stable Version of yt and Trident

Installation of the stable versions of yt and Trident is quite simple:

$ pip install trident

Now, you can try to run Trident for the first time, where it will download some additional files. See Step 3: Get Ionization Table and Verify Installation, for more information:

$ python
>>> import trident

Follow the instructions to download the ion_balance table and then verify that everything is working correctly. You should now be ready to do some Step 4: Science!

Installing the Development Version of yt and Trident

Step 0: Ensure Conda is Installed

Conda is a package manager providing a clean, stand-alone installation of python that is self-contained in its installation directory. yt & trident require a modern installation of python to work. conda provides that installation.

You can see if conda is already installed by running:

$ conda -h

If conda is installed, move to the next step. Otherwise install Mini-conda.

Use the appropriate conda install script for your architecture. We recommend getting the latest version of conda for Python3 for your architecture here:

For modern macs:

$ curl -O
$ bash

For modern linux machines:

$ wget
$ bash

At the end of the installation step, allow conda to add its installation directory to the $PATH.

Step 1: Install yt

First you need yt’s major dependencies:

$ conda install numpy cython mpi4py git

Now you pull directly from the yt github repository to access the up-to-date version of the source code and build it:

$ git clone yt
$ cd yt
$ pip install -e .
$ cd ..

Note, you’ll also need a separate library, yt_astro_analysis, to get some of the functionality necessary for Trident to work correctly:

$ git clone yt_astro_analysis
$ cd yt_astro_analysis
$ pip install -e .
$ cd ..

Step 2: Install Trident

Like yt, in order to get the development version of Trident, you must clone and build the up-to-date source code from its repository:

$ git clone trident
$ cd trident
$ pip install -e .
$ cd ..

Step 3: Get Ionization Table and Verify Installation

In order to calculate the ionization fractions for various ions from density, temperature, metallicity fields, you will need an ionization table datafile and a configuration file. Because this datafile can be large, it is not packaged with the main source code. The first time you try to do anything that requires it, Trident will attempt to automatically set this all up for you with a series of interactive prompts. This step requires an internet connection the first time you run it.

In addition, Trident provides a simple test function to verify that your install is functioning correctly. This function not only tries to set up your configuration and download your ion table file, but it will create a simple one-zone dataset, generate a ray through it, and create a spectrum from that ray. This should execute very quickly, and if it succeeds it demonstrates that your installation has been totally successful:

$ python
>>> import trident
>>> trident.verify()
...Series of Interactive Prompts...

If you cannot directly access the internet on this computer, or you lack write access to your $HOME directory, or this step fails for any reason, please follow our documentation on Manually Installing your Ionization Table.

Step 4: Science!

Congratulations, you’re now ready to use Trident! Please refer to the documentation for how to use it with your data or with one of our sample datasets. A good place to start is the annotated example, and the example scripts found in the source code.

Please join our mailing list or slack channel for announcements and updates when new features are added to the code.

Manually Installing your Ionization Table

If for some reason you are unable to install the config file and ionization table data automatically, you must set it up manually. When Trident runs, it looks for a configuration file called config.tri in the $HOME/.trident directory or alternatively in the current working directory (for users lacking write access to their $HOME directories). This configuration file is simple in that it tells Trident a few things about your install including the location and filename of your desired ionization table. Manually create a text file called config.tri with contents following the form:

ion_table_dir = ~/.trident
ion_table_file = hm2012_hr.h5

To manually obtain an ion table datafile, download and gunzip one from: . While the config.tri file needs to exist in your $HOME/.trident directory or in the working directory when you import trident, the ion_table datafile can exist anywhere on the file system. Just assure that the config file points to the proper location and filename of the ion table datafile.

Now, to confirm everything is working properly, verify your installation following Step 3: Get Ionization Table and Verify Installation. If this fails or you have additional problems, please contact our mailing list.

Uninstallation or Switching Code Versions

Uninstallation of the Trident source code is easy. If you installed the stable version of the code via pip, just run:

$ pip uninstall trident

If you installed the dev version of Trident, you’ll have to delete the source as well:

$ pip uninstall trident

If you want to switch between the two stable and development versions, just uninstall your version of the code as above, and then install the desired version as described in Step 2: Install Trident

To fully remove the code from your system, remember to remove any ion table datafiles you may have downloaded in your $HOME/.trident directory, and follow the instructions for how to uninstall yt.

Updating to the Latest Version

If you want more recent features, you should periodically update your Trident codebase.

Updating to the Latest Stable Release

If you installed the “stable” version of the code using pip, then you can easily update your trident and yt installations:

$ pip install -U trident
$ yt update

Updating to the Latest Development Version

If you installed the “development” version of the code, it’s slightly more involved:

$ git pull origin main
$ pip install -e .
$ yt update

For more information on updating your yt installation, see the yt update instructions.