Mailman 3 July 2021 - yt-users

Problems with running Rockstar from Yt
by Nick Gnedin 13 Jul '21

13 Jul '21

It appears that Yt does not run Rockstar correctly. Here are 2 issues we discovered so far: 1. DM particle mass and hence halo masses are incorrect in a simulation with baryons. Here are lines from one of out_*.list for a simulation with 1024^3 particles in a 40 cMpc/h box: #Om = 0.303600; Ol = 0.696400; h = 0.681400 #Particle mass: 4.22991e+06 Msun/h The particle mass should be 2.77536623e11*0.3036/0.6814*40**3/1024**3 = 7370552 Msun Instead, the reported value is 4.22991e+06 Msun/h = 6207675 Msun, which is exactly 2.77536623e11*0.2557/0.6814*40**3/1024**3 and 0.2557 = Omega_{DM}, not Omega_M. The same incorrect value is reported independently of what I set for the dm_only argument to RockstarHaloFinder. In a DMO simulation with identical initial conditions the particle mass is reported correctly: #Particle mass: 5.02229e+06 Msun/h This is for the snapshot read by the artio frontend. 2. I tried to circumvent the previous bug by setting particle_mass=5.02229e+06 in the call to RockstarHaloFinder, but that dies with the following error: p['particle_mass'].convert_to_units("Msun / h") P002 yt : [ERROR ] 2021-06-01 19:17:19,937 AttributeError: 'float' object has no attribute 'convert_to_units' It appears that the argument of particle_mass keyword must be some class rather than a number as listed in the documentation. 3. When running on a simulation with a non-zero DC mode Yt sets the box size incorrectly: > fgrep '#Box size' out_* out_0.list:#Box size: 40.216236 Mpc/h out_1.list:#Box size: 40.216236 Mpc/h ... out_14.list:#Box size: 40.216236 Mpc/h It appears that Yt uses the value Lbox*abox/auni for the first snapshot, and never recomputes it for the following snapshots. That corrupts halo positions, and, what is even worse, applies periodic wrapping incorrectly, so halos near the box boundaries are messed up. Nick Gnedin -- This email has been checked for viruses by AVG. https://www.avg.com

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Light cone projection
by Tseng, Po-Hsun 13 Jul '21

13 Jul '21

Hi all, I would like to make a light cone projection from hydrodynamic, not cosmological, data set. What I mean by **light cone projection** is: Given the coordinate of camera in simulation box and opening angle of the light cone, we can project 3D gas distribution onto a 2D plane. I found there is a similar API in the yt manual can do this, but it is for cosmological analysis not for hydrodynamics. Does anyone has suggestions? Thanks.

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ANN: yt 4.0.0 release
by Madicken Munk 07 Jul '21

07 Jul '21

Dear yt users and developers, The yt community is proud to announce the release of yt-4.0! yt (http://yt-project.org) is an open source, community-developed toolkit for analysis and visualization of volumetric data. This release features a complete reworking of a number of internal components, most importantly those related to particles and discrete points. In keeping with this, we expect that some scripts used for analysis will require modifications; information about "what's new" as well as instructions for how to update analysis scripts can be found at: https://yt-project.org/docs/4.0.0/yt4differences.html . A set of highlights of the pull requests that went into this release can be found here: https://gist.github.com/matthewturk/7a1f21d98aa5188de7645eda082ce4e6#file-h… A full listing of the pull requests that went into this release can be found here: https://gist.github.com/matthewturk/7a1f21d98aa5188de7645eda082ce4e6#file-y… This release has been years in the making, and features contributions from dozens of individuals, many of whom were new to the project. It marks the culmination of a set of wide-reaching infrastructure changes that result in much higher fidelity to the underlying data for particle datasets. At the end of this email you can find a non-exhaustive list of individuals who have contributed to this release; many of them made their first contribution during this release! Binaries for yt 4.0 are available via pip and conda. If you use conda to manage your Python installation, you can update yt via: $ conda update -c conda-forge yt If you manage your Python installation with pip, you can update yt via: $ python -m pip install -U yt For more information, including installation instructions, links to community resources, and information on contributing to yt’s development, please see the yt homepage at https://yt-project.org and the documentation for yt-4.0 at http://yt-project.org/docs/4.0.0 We especially thank Nathan Goldbaum for his many years of work and contributions to this release and to the yt community. 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. If you are interested in contributing to yt, please see our repository on GitHub at http://github.com/yt-project/yt Thank you for being a part of the community, The yt team Contributors to this release (first time contributors are marked with "*") Ashley Kelly Axel Huebl * Baptiste Mouginot * Ben Kimock * Bili Dong Brandon Qiao Britton Smith Cameron Hummels Camille Avestruz * Chris Havlin * Christopher W. Evans * Clayton Strawn Clément Robert Corentin Cadiou David Grote * Desika Narayanan * Jared Coughlin * Jody Klymak * John Regan John ZuHone Kacper Kowalik Kelton Halbert * Madicken Munk Matthew Abruzzo * Matthew Turk Matthias Bussonnier * Meagan Lang * Michael Zingale Miguel de Val-Borro Nathan Goldbaum Neïl Zaim * Niels Claes Ole Streicher * Philipp Edelmann * Revathi Jambunathan * Shea Garrison-Kimmel * Stefan Arridge *

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