Make the disk patch example solution script use the pressure in the snapshots...

Make the disk patch example solution script use the pressure in the snapshots and not the internal energy.

examples/GravityTests/DiscPatch/HydroStatic/plotSolution.py

@@ -62,11 +62,9 @@ def get_analytic_pressure(x):
 def get_data(name):
   file = h5py.File(name, "r")
   coords = np.array(file["/PartType0/Coordinates"])
-  rho = np.array(file["/PartType0/Density"])
-  u = np.array(file["/PartType0/InternalEnergy"])
+  rho = np.array(file["/PartType0/Densities"])
   v = np.array(file["/PartType0/Velocities"])
-
-  P = (gamma - 1.) * rho * u
+  P = np.array(file["/PartType0/Pressures"])
 
   vtot = np.sqrt( v[:,0]**2 + v[:,1]**2 + v[:,2]**2 )
 
@@ -79,7 +77,7 @@ for f in sorted(glob.glob("Disc-Patch_*.hdf5")):
   if num < start or num > stop:
     continue
 
-  print "processing", f, "..."
+  print("processing", f, "...")
 
   xrange = np.linspace(0., 2. * x_disc, 1000)
   time, x, rho, P, v = get_data(f)