"""
This is a simple recipe to show how to open a dataset, plot a slice
through it, and add velocity vectors on top.
"""
from yt.mods import * # set up our namespace

fn = "RedshiftOutput0005" # parameter file to load

pf = load(fn) # load data
pc = PlotCollection(pf) # defaults to center at most dense point
p = pc.add_slice("Density", 0) # 0 = x-axis
p.modify["velocity"]() # This takes a few arguments, but we'll use the defaults
                       # here.  You can control the 'skip' factor in the
                       # vectors.
pc.set_width(2.5, 'mpc') # change width of all plots in pc
pc.save(fn) # save all plots