Enzo v2.0 documentation

Analyzing With YT

What is YT?

YT is a python-based tool designed for analyzing and visualizing Adaptive Mesh Refinement data, specifically as output from Enzo. YT is completely free and open source, with an active and expanding development community, and it presents to the user both high-level and low-level APIs. The documentation contains a tutorial as well as an API reference, but here we will step through some simple steps toward creating script to make simple plots of a cosmological simulation.

This brief tutorial presupposes that you have run the installation script (See Installation) and are comfortable launching python. (The install script will tell you how!) It’s also encouraged to launch the special YT-enhanced IPython shell via the command iyt, which (thanks to IPython!) features filesystem navigation and tab completion, along with interactive plotting capabilities.

Making Slices

Here is a sample script that will make a set of slices centered on the maximum density location, with a width of 100 kpc.

from yt.mods import *
pf = EnzoStaticOutput("RedshiftOutput0035.dir/RedshiftOutput0035")

pc = raven.PlotCollection(pf)
pc.add_slice("Density",0)
pc.add_slice("Density",1)
pc.add_slice("Density",2)
pc.set_width(100.0,'kpc')
pc.save("z35_100kpc")

If you put this into a file called my\_script.py, you can execute it with python2.5 my\_script.py and it will save out a set of images prefixed with z35\_100kpc in PNG format.

Making Simple Radial Profiles

If you want to make radial profiles, you can generate and plot them very easily with YT. Here is a sample script to do so.

from yt.mods import *
pf = EnzoStaticOutput("RedshiftOutput0035.dir/RedshiftOutput0035")

pc = PlotCollection(pf)

pc.add_profile_sphere(100.0, 'kpc', ["Density", "Temperature"])
pc.save("z35_100kpc")

pc.switch_z("VelocityMagnitude")
pc.save("z35_100kpc")

To show the mass distribution in the Density-Temperature plane, we would make a phase diagram.

from yt.mods import *
pf = EnzoStaticOutput("RedshiftOutput0035.dir/RedshiftOutput0035")

pc = PlotCollection(pf)

pc.add_phase_sphere(100.0, 'kpc', ["Density", "Temperature", "CellMassMsun"], weight=None)
pc.save("z35_100kpc")

More Information

For more information on yt, see the yt website, where you will find mailing lists, documentation, API documentation, a cookbook and even a gallery of images.