What to do if you run into problems

If you run into problems with yt, there are a number of steps to follow to come to a solution. The first handful of options are things you can do on your own, but if those don’t yield results, we have provided a number of ways to connect with our community of users and developers to solve the problem together.

To summarize, here are the steps in order:

  1. Don’t panic and don’t give up
  2. Update to the latest version
  3. Search the yt documentation and mailing list archives
  4. Look at the yt source
  5. Isolate & document your problem
  6. Go on IRC and ask a question
  7. Ask the mailing list
  8. Submit a bug report

Don’t panic and don’t give up

This may seem silly, but it’s effective. While yt is a robust code with lots of functionality, like all actively-developed codes sometimes there are bugs. Chances are good that your problems have a quick fix, either because someone encountered it before and fixed it, the documentation is out of date, or some other simple solution. Don’t give up! We want to help you succeed!

Try updating yt

Sometimes the pace of development is pretty fast on yt, particularly in the development branch, so a fix to your problem may have already been developed by the time you encounter it. Many users’ problems can simply be corrected by updating to the latest version of the code and/or its dependencies. You can update yt’s source by running:

$ yt update

or you could update yt’s source as well as any software dependencies by running:

$ yt update --all

Search the documentation and mailing lists

The documentation has a lot of the answers to everyday problems. This doesn’t mean you have to read all of the docs top-to-bottom, but you should at least run a search to see if relevant topics have been answered in the docs. Click on the search field to the right of this window and enter your text. Another good place to look for answers in the documentation is our Frequently Asked Questions page.

OK, so there was no obvious solution to your problem in the documentation. It is possible that someone else experienced the problem before you did, and wrote to the mailing list about it. You can easily check the mailing list archive with the other search field to the right of this window (or you can use the search field below).

Look at the source code

We’ve done our best to make the source clean, and it is easily searchable from your computer. Go inside your yt install directory by going to the $YT_DEST/src/yt-hg/yt directory where all the code lives. You can then search for the class, function, or keyword which is giving you problems with grep -r *, which will recursively search throughout the code base. (For a much faster and cleaner experience, we recommend grin instead of grep -r *. To install grin with python, just type pip install grin.)

So let’s say that pesky SlicePlot is giving you problems still, and you want to look at the source to figure out what is going on.

$ cd $YT_DEST/src/yt-hg/yt
$ grep -r SlicePlot *         (or $ grin SlicePlot)

 data_objects/analyzer_objects.py:class SlicePlotDataset(AnalysisTask):
 data_objects/analyzer_objects.py:        from yt.visualization.api import SlicePlot
 data_objects/analyzer_objects.py:        self.SlicePlot = SlicePlot
 data_objects/analyzer_objects.py:        slc = self.SlicePlot(pf, self.axis, self.field, center = self.center)

You can now followup on this and open up the files that have references to SlicePlot (particularly the one that definese SlicePlot) and inspect their contents for problems or clarification.

Isolate and document your problem

As you gear up to take your question to the rest of the community, try to distill your problem down to the fewest number of steps needed to produce it in a script. This can help you (and us) to identify the basic problem. Follow these steps:

  • Identify what it is that went wrong, and how you knew it went wrong.
  • Put your script, errors, and outputs online:
    • $ yt pastebin script.py - pastes script.py online
    • $ python script.py --paste - pastes errors online
    • $ yt upload_image image.png - pastes image online
  • Identify which version of the code you’re using.
    • $ yt instinfo - provides version information, including changeset hash

It may be that through the mere process of doing this, you end up solving the problem!


If you want a fast, interactive experience, you could try jumping into our IRC channel to get your questions answered in a chatroom style environment. You don’t even need to have any special IRC client in order to join. We are the #yt channel on irc.freenode.net, but you can also connect using your web browser by going to http://yt-project.org/irc.html . There are usually 2-8 members of the user base and development team online, so you’ll probably get your answers quickly. Remember to bring the information from the last step.

Ask the mailing list

If you still haven’t yet found a solution, feel free to write to the mailing list regarding your problems. There are two mailing lists, yt-users and yt-dev. The first should be used for asking for help, suggesting features and so on, and the latter has more chatter about the way the code is developed and discussions of changes and feature improvements.

If you email yt-users asking for help, remember to include the information about your problem you identified in this step.

When you email the list, providing this information can help the developers understand what you did, how it went wrong, and any potential fixes or similar problems they have seen in the past. Without this context, it can be very difficult to help out!

How To report A bug

If you have gone through all of the above steps, and you’re still encountering problems, then you have found a bug. To submit a bug report, you can either directly create one through the BitBucket web interface, or you can use the command line yt bugreport to interactively create one. Alternatively, email the yt-users mailing list and we will construct a new ticket in your stead. Remember to include the information about your problem you identified in this step.

Installation Issues

If you are having installation issues and nothing from the installation instructions seems to work, you should definitely email the yt-users email list. You should provide information about the host, the version of the code you are using, and the output of yt_install.log from your installation. We are very interested in making sure that yt installs everywhere!

Customization and Scripting Issues

If you have customized yt in some way, or created your own plugins file (as described in What is the “Plugin File”?) then it may be necessary to supply both your patches to the source, the plugin file, and perhaps even the datafile on which you’re running.