yt comes with a command-line tool, known as yt, that exposes much of the functionality that would normally be accessible through a scripts. This is designed to make the process of making immediate plots much easier. All of the functionality is described in the help strings:
$ yt help
and then the subcommands all have help options as well:
$ yt plot --help
In order to actually run the command, you’ll need to tell it which outputs to operate on. The yt command-line tool has three mechanisms for specifying outputs. It will do its best to guess based on the information its provided.
You can specify a base name for a parameter file and then a start and stop number (and optionally a skip parameter):
$ yt plot --basename=RedshiftOutput --skip 5 10 50
This will run your plot command on RedshiftOutput 10 through 50, but only on multiples of five. (And if your output is in a subdirectory, yt will check there too, don’t worry!)
You can specify a single parameter file:
$ yt plot RedshiftOutput0010
This will run your plot command on RedshiftOutput0010.
Alternatively, you can specify multiple parameter files on the command line:
$ yt plot RedshiftOutput0010 RedshiftOutput0020 RedshiftOutput0030
This will plot RedshiftOutput0010, RedshiftOutput0020, and RedshiftOutput0030.
To get information about a given parameter file, including the maximum density, the level information, the smallest cell size and some timing information, use the stats command:
$ yt stats RedshiftOutput0005
0 4 32768
1 34 253496
2 304 525784
----------------------------
342 812048
z = 0.00000000
t = 6.46750660e+02 = 4.57786981e+17 s = 1.45163299e+10 years
Smallest Cell:
Width: 7.812e-03 1
Width: 7.812e-03 unitary
Width: 3.906e-02 mpch
Width: 3.906e-02 mpchcm
Width: 6.010e-02 mpc
Width: 7.812e-01 aye
Width: 3.906e+01 kpch
Width: 3.906e+01 kpchcm
Width: 6.010e+01 kpc
Width: 3.906e+04 pch
Width: 3.906e+04 pchcm
Width: 6.010e+04 pc
Width: 8.059e+09 auh
Width: 8.059e+09 auhcm
Width: 1.240e+10 au
Width: 8.659e+11 rsunh
Width: 8.659e+11 rsunhcm
Width: 1.332e+12 rsun
Width: 7.488e+17 milesh
Width: 7.488e+17 mileshcm
Width: 1.152e+18 miles
Width: 1.205e+23 cmh
Width: 1.205e+23 cmhcm
Width: 1.854e+23 cm
Maximum density: 4.43898e-27 at (0.94921875, 0.80078125, 0.61328125)
The command line tool can make either projections or slices. To make a projection, supply it with the -p option:
$ yt plot -p RedshiftOutput0005
If you don’t supply the -p option, it will only slice rather than project through the object. Weights can also be supplied for an average along the line of sight. This command defaults to the full width, centered on the most dense point, and outputting along all three axes. The help command has more information:
Create a set of images
Usage:
yt plot [ARGS...]
Options:
-h, --help show this help message and exit
-w WIDTH, --width=WIDTH
Width in specified units
-u UNIT, --unit=UNIT
Desired units
-b BASENAME, --basename=BASENAME
Basename of parameter files
-p, --projection Use a projection rather than a slice
-c CENTER, --center=CENTER
Center (-1,-1,-1 for max)
-z ZLIM, --zlim=ZLIM
Color limits (min, max)
-a AXIS, --axis=AXIS
Axis (4 for all three)
-f FIELD, --field=FIELD
Field to color by
-g WEIGHT, --weight=WEIGHT
Field to weight projections with
-s SKIP, --skip=SKIP
Skip factor for outputs
--colormap=CMAP Colormap name
-o OUTPUT, --output=OUTPUT
Folder in which to place output images
--show-grids Show the grid boundaries
The command line tool also has facilities for outputting a set of frames that zoom in on a central position. This works on a single dataset and can zoom in on projections or slices:
$ yt zoomin RedshiftOutput0005
However, as with the other commands, you will likely want to specify your own options.
Create a set of zoomin frames
Options:
-h, --help show this help message and exit
--max-width=MAX_WIDTH
Maximum width in code units
--min-width=MIN_WIDTH
Minimum width in units of smallest dx (default: 50)
-p, --projection Use a projection rather than a slice
-a AXIS, --axis=AXIS
Axis (4 for all three)
-f FIELD, --field=FIELD
Field to color by
-g WEIGHT, --weight=WEIGHT
Field to weight projections with
-z ZLIM, --zlim=ZLIM
Color limits (min, max)
-n NFRAMES, --nframes=NFRAMES
Number of frames to generate
-o OUTPUT, --output=OUTPUT
Folder in which to place output images
--colormap=CMAP Colormap name
--unit-boxes Display helpful unit boxes
--dex=DEX Number of dex above min to display
-t TEXT, --text=TEXT
Textual annotation