The yt community is proud to announce the release of yt 3.5.0. This is a major
release and includes a number of new features, minor improvements, and bugfixes.

yt ( is an open source, community developed toolkit for
the analysis and visualization of volumetric data.

If you are interested in contributing to yt, please see our repository on GitHub

Since yt 3.4.0 we have merged 328 pull requests from 41 contributors, including
23 new contributors. We would like to thank the following people who made code
contributions to this release, new contributors are marked with an asterisk.

Ashley Kelly *
Fabian Koller
Enrico Garaldi *
Hugo Pfister *
Josh Borrow *
Kiran Eiden *
Matthew Turk
Prateek Gupta *
Ricarda Beckmann
Kacper Kowalik
Andrew Myers
Brandon Qiao *
Britton Smith
Christoph Behrens *
Cameron Hummels
Claire Kopenhafer *
Clayton Strawn *
Corentin Cadiou
David Pérez-Suárez *
Donald E Willcox *
Hilary Egan
Abhishek Singh *
Hsi-Yu Scive
Suoqing Ji
Josh Soref *
John ZuHone
Max Gronke *
Max Katz
Miguel de Val-Borro
Marianne Corvellec *
Madicken Munk *
Clément Robert *
Nick Gnedin *
Nathan Goldbaum
Philip Grete *
Bili Dong
Sean Larkin *
Stephanie Ho *
Yi-Hao Chen
Ying-Chao Lu *
Mike Zingale

We would also like to thank everyone who has contributed in other ways,
including by reporting issues, participating on the mailing list, and
evangelizing yt to your colleagues.

Additionally, we would like to highlight the contributions of Ashley Kelly and
Abhishek Singh, who contributed to this release in the context of Google Summery
of Code projects. Both students passed their evaluations and made substantial
improvements to yt. You can find out more about Ashley and Abhishek's projects
on the Summer of Code website:

Finally, we would also like to highlight the contributions of Corentin Cadiou, who has
made substantial performance and functionality improvements to the RAMSES
frontend as part of this release. Corentin's contributions came in on a
volunteer basis and we thank him for his tireless efforts to improve yt's
support for RAMSES data.

Binaries for yt 3.5.0 are available via pip and conda. If you installed via the
install script or use conda to manage your python installation, you can update
yt via:

$ conda update -c conda-forge yt

Conda-forge package updates may not be up quite yet but should be uploaded by
the end of the day.

And if you manage your python installation with pip:

$ pip install -U yt

As always, if you have any questions, concerns, or run into any trouble updating
please don’t hesitate to send a message to the mailing list or stop by our Slack
or IRC channel.

yt is the product of a large community of developers and users and we are
extraordinarily grateful for and proud of their contributions. Please forward
this announcement on to any interested parties.

The yt development team

What's new?

Please see the release notes for full details
(, but
we highlight a few major changes and improvements here.

* yt.analysis_modules has been deprecated in favor of the new yt_astro_analysis
  package. New features and new astronomy-specific analysis modules will go into
  yt_astro_analysis and importing from yt.analysis_modules will raise a noisy
  warning. We will remove yt.analysis_modules in a future release

* Vector fields and derived fields depending on vector fields have been
  systematically updated to account for a bulk correction field parameter. For
  example, for the velocity field, all derived fields that depend on velocity
  will now account for the "bulk_velocity" field parameter. In addition, we have
  defined "relative_velocity" and "relative_magnetic_field" fields that include
  the bulk correction. Both of these are vector fields, to access the
  components, use e.g. "relative_velocity_x". The "particle_position_relative"
  and "particle_velocity_relative" fields have been deprecated.

* The RAMSES frontend has seen considerable improvements, with support for the
  new RAMSES self-describing particle output format, considerable speed
  improvements for I/O and initially loading data, and support for restricting
  the domain to a subset of the full simulation volume for imrpoved speed and
  reduced memory usage for large datasets.

* Aliases to spatial fields with the "gas" field type will now be
  returned in the default unit system for the dataset. As an example the "x"
  field might resolve to the field tuples ("index", "x") or ("gas",
  "x"). Accessing the former will return data in code units while the latter
  will return data in whatever unit system the dataset is configured to use
  (CGS, by default). This means that to ensure the units of a spatial field will
  always be consistent, one must access the field as a tuple, explicitly
  specifying the field type. Accessing a spatial field using a string field name
  may return data in either code units or the dataset’s default unit system
  depending on the history of field accesses prior to accessing that field. In
  the future accessing fields using an ambiguous field name will raise an

* The max_level and min_level attributes of yt data objects now correctly update
  the state of the underlying data objects when set. In addition we have added
  an example to the cookbook that shows how to downsample AMR data using this

* It is now possible to customize the formatting of
  labels for ion species fields. Rather than using the default spectroscopic
  notation, one can call ds.set_field_label_format("ionization_label",
  "plus_minus") to use the more traditional notation where ionization state is
  indicated with + and - symbols.