import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import AxesGrid

import yt

fn = "IsolatedGalaxy/galaxy0030/galaxy0030"
ds = yt.load(fn)  # load data

fig = plt.figure()

# See http://matplotlib.org/mpl_toolkits/axes_grid/api/axes_grid_api.html
# These choices of keyword arguments produce a four panel plot that includes
# four narrow colorbars, one for each plot.  Axes labels are only drawn on the
# bottom left hand plot to avoid repeating information and make the plot less
# cluttered.
grid = AxesGrid(
    fig,
    (0.075, 0.075, 0.85, 0.85),
    nrows_ncols=(2, 2),
    axes_pad=1.0,
    label_mode="1",
    share_all=True,
    cbar_location="right",
    cbar_mode="each",
    cbar_size="3%",
    cbar_pad="0%",
)

fields = [
    ("gas", "density"),
    ("gas", "velocity_x"),
    ("gas", "velocity_y"),
    ("gas", "velocity_magnitude"),
]

# Create the plot.  Since SlicePlot accepts a list of fields, we need only
# do this once.
p = yt.SlicePlot(ds, "z", fields)

# Velocity is going to be both positive and negative, so let's make these
# slices use a linear colorbar scale
p.set_log(("gas", "velocity_x"), False)
p.set_log(("gas", "velocity_y"), False)

p.zoom(2)

# For each plotted field, force the SlicePlot to redraw itself onto the AxesGrid
# axes.
for i, field in enumerate(fields):
    plot = p.plots[field]
    plot.figure = fig
    plot.axes = grid[i].axes
    plot.cax = grid.cbar_axes[i]

# Finally, redraw the plot on the AxesGrid axes.
p.render()

plt.savefig("multiplot_2x2.png")