diff --git a/examples/ExternalPointMass/energy_plot.py b/examples/ExternalPointMass/energy_plot.py
new file mode 100644
index 0000000000000000000000000000000000000000..a75fcb835d33b3695170aab822092556f12db7d1
--- /dev/null
+++ b/examples/ExternalPointMass/energy_plot.py
@@ -0,0 +1,121 @@
+import matplotlib
+matplotlib.use("Agg")
+from pylab import *
+import h5py
+
+# Plot parameters
+params = {'axes.labelsize': 10,
+'axes.titlesize': 10,
+'font.size': 12,
+'legend.fontsize': 12,
+'xtick.labelsize': 10,
+'ytick.labelsize': 10,
+'text.usetex': True,
+ 'figure.figsize' : (3.15,3.15),
+'figure.subplot.left' : 0.145,
+'figure.subplot.right' : 0.99,
+'figure.subplot.bottom' : 0.11,
+'figure.subplot.top' : 0.99,
+'figure.subplot.wspace' : 0.15,
+'figure.subplot.hspace' : 0.12,
+'lines.markersize' : 6,
+'lines.linewidth' : 3.,
+'text.latex.unicode': True
+}
+rcParams.update(params)
+rc('font',**{'family':'sans-serif','sans-serif':['Times']})
+
+
+import numpy as np
+import h5py as h5
+import sys
+
+# File containing the total energy
+stats_filename = "./energy.txt"
+
+# First snapshot
+snap_filename = "pointMass_000.hdf5"
+f = h5.File(snap_filename,'r')
+
+# Read the units parameters from the snapshot
+units = f["InternalCodeUnits"]
+unit_mass = units.attrs["Unit mass in cgs (U_M)"]
+unit_length = units.attrs["Unit length in cgs (U_L)"]
+unit_time = units.attrs["Unit time in cgs (U_t)"]
+
+G = 6.67408e-8 * unit_mass * unit_time**2 / unit_length**3
+
+# Read the header
+header = f["Header"]
+box_size = float(header.attrs["BoxSize"][0])
+
+# Read the properties of the potential
+parameters = f["Parameters"]
+mass = float(parameters.attrs["PointMassPotential:mass"])
+centre = [box_size/2, box_size/2, box_size/2]
+f.close()
+
+# Read the statistics summary
+file_energy = np.loadtxt("energy.txt")
+time_stats = file_energy[:,0]
+E_kin_stats = file_energy[:,3]
+E_pot_stats = file_energy[:,5]
+E_tot_stats = E_kin_stats + E_pot_stats
+
+# Read the snapshots
+time_snap = np.zeros(402)
+E_kin_snap = np.zeros(402)
+E_pot_snap = np.zeros(402)
+E_tot_snap = np.zeros(402)
+Lz_snap = np.zeros(402)
+
+# Read all the particles from the snapshots
+for i in range(402):
+ snap_filename = "pointMass_%0.3d.hdf5"%i
+ f = h5.File(snap_filename,'r')
+
+ pos_x = f["PartType1/Coordinates"][:,0]
+ pos_y = f["PartType1/Coordinates"][:,1]
+ pos_z = f["PartType1/Coordinates"][:,2]
+ vel_x = f["PartType1/Velocities"][:,0]
+ vel_y = f["PartType1/Velocities"][:,1]
+ vel_z = f["PartType1/Velocities"][:,2]
+ m = f["/PartType1/Masses"][:]
+
+ r = np.sqrt((pos_x[:] - centre[0])**2 + (pos_y[:] - centre[1])**2 + (pos_z[:] - centre[2])**2)
+ Lz = (pos_x[:] - centre[0]) * vel_y[:] - (pos_y[:] - centre[1]) * vel_x[:]
+
+ time_snap[i] = f["Header"].attrs["Time"]
+ E_kin_snap[i] = np.sum(0.5 * m * (vel_x[:]**2 + vel_y[:]**2 + vel_z[:]**2))
+ E_pot_snap[i] = np.sum(-mass * m * G / r)
+ E_tot_snap[i] = E_kin_snap[i] + E_pot_snap[i]
+ Lz_snap[i] = np.sum(Lz)
+
+# Plot energy evolution
+figure()
+plot(time_stats, E_kin_stats, "r-", lw=0.5, label="Kinetic energy")
+plot(time_stats, E_pot_stats, "g-", lw=0.5, label="Potential energy")
+plot(time_stats, E_tot_stats, "k-", lw=0.5, label="Total energy")
+
+plot(time_snap[::10], E_kin_snap[::10], "rD", lw=0.5, ms=2)
+plot(time_snap[::10], E_pot_snap[::10], "gD", lw=0.5, ms=2)
+plot(time_snap[::10], E_tot_snap[::10], "kD", lw=0.5, ms=2)
+
+legend(loc="center right", fontsize=8, frameon=False, handlelength=3, ncol=1)
+xlabel("${\\rm{Time}}$", labelpad=0)
+ylabel("${\\rm{Energy}}$",labelpad=0)
+xlim(0, 8)
+
+savefig("energy.png", dpi=200)
+
+# Plot angular momentum evolution
+figure()
+plot(time_snap, Lz_snap, "k-", lw=0.5, ms=2)
+
+xlabel("${\\rm{Time}}$", labelpad=0)
+ylabel("${\\rm{Angular~momentum}}$",labelpad=0)
+xlim(0, 8)
+
+savefig("angular_momentum.png", dpi=200)
+
+
diff --git a/examples/ExternalPointMass/externalPointMass.yml b/examples/ExternalPointMass/externalPointMass.yml
index 621a66bbc39838ac8d3d8a8a3992b2a7be3157a8..f77b4632c67115559ab2d45083eb7778d21903d8 100644
--- a/examples/ExternalPointMass/externalPointMass.yml
+++ b/examples/ExternalPointMass/externalPointMass.yml
@@ -9,7 +9,7 @@ InternalUnitSystem:
# Parameters governing the time integration
TimeIntegration:
time_begin: 0. # The starting time of the simulation (in internal units).
- time_end: 1. # The end time of the simulation (in internal units).
+ time_end: 8. # The end time of the simulation (in internal units).
dt_min: 1e-6 # The minimal time-step size of the simulation (in internal units).
dt_max: 1e-3 # The maximal time-step size of the simulation (in internal units).
diff --git a/examples/ExternalPointMass/makeIC.py b/examples/ExternalPointMass/makeIC.py
index 326183398933c88d7348e72e00343064b3e3a64c..a324220e183baed4ac5aaaf2d71cf5b6ea15c1ce 100644
--- a/examples/ExternalPointMass/makeIC.py
+++ b/examples/ExternalPointMass/makeIC.py
@@ -27,7 +27,7 @@ import random
# Generates a random distriution of particles, for motion in an external potnetial centred at (0,0,0)
# physical constants in cgs
-NEWTON_GRAVITY_CGS = 6.672e-8
+NEWTON_GRAVITY_CGS = 6.67408e-8
SOLAR_MASS_IN_CGS = 1.9885e33
PARSEC_IN_CGS = 3.0856776e18
diff --git a/examples/ExternalPointMass/run.sh b/examples/ExternalPointMass/run.sh
index 8b745746e40341dc019005912fe1e6a75e0e87ac..44daaaaf5b92c2923527daf256a61fbb4403b73f 100755
--- a/examples/ExternalPointMass/run.sh
+++ b/examples/ExternalPointMass/run.sh
@@ -9,3 +9,5 @@ fi
rm -rf pointMass_*.hdf5
../swift -g -t 1 externalPointMass.yml 2>&1 | tee output.log
+
+python energy_plot.py
diff --git a/examples/ExternalPointMass/test.pro b/examples/ExternalPointMass/test.pro
deleted file mode 100644
index 21c10e9d27daa45b085c6a659ba3cf7260f017fb..0000000000000000000000000000000000000000
--- a/examples/ExternalPointMass/test.pro
+++ /dev/null
@@ -1,65 +0,0 @@
-;
-; test energy / angular momentum conservation of test problem
-;
-@physunits
-
-indir = '/gpfs/data/tt/Codes/Swift-git/swiftsim/examples/'
-basefile = 'output_'
-nfiles = 657
-nfollow = 100 ; number of particles to follow
-eout = fltarr(nfollow, nfiles)
-ekin = fltarr(nfollow, nfiles)
-epot = fltarr(nfollow, nfiles)
-tout = fltarr(nfiles)
-; set properties of potential
-uL = 1e3 * phys.pc ; unit of length
-uM = phys.msun ; unit of mass
-uV = 1d5 ; unit of velocity
-
-; derived units
-constG = 10.^(alog10(phys.g)+alog10(uM)-2d0*alog10(uV)-alog10(uL)) ;
-pcentre = [50.,50.,50.] * 1d3 * pc / uL
-mextern = 1d10 * msun / uM
-;
-;
-;
-ifile = 0
-for ifile=0,nfiles-1 do begin
-;for ifile=0,3 do begin
- inf = indir + basefile + strtrim(string(ifile,'(i3.3)'),1) + '.hdf5'
- time = h5ra(inf, 'Header','Time')
- p = h5rd(inf,'PartType1/Coordinates')
- v = h5rd(inf,'PartType1/Velocities')
- id = h5rd(inf,'PartType1/ParticleIDs')
- indx = sort(id)
-;
- id = id[indx]
- for ic=0,2 do begin
- tmp = reform(p[ic,*]) & p[ic,*] = tmp[indx]
- tmp = reform(v[ic,*]) & v[ic,*] = tmp[indx]
- endfor
-; calculate energy
- dd = size(p,/dimen) & npart = dd[1]
- ener = fltarr(npart)
- dr = fltarr(npart) & dv = dr
- for ic=0,2 do dr[*] = dr[*] + (p[ic,*]-pcentre[ic])^2
- for ic=0,2 do dv[*] = dv[*] + v[ic,*]^2
- dr = sqrt(dr)
-; print,'time = ',time,p[0,0],v[0,0],id[0]
- ek = 0.5 * dv
- ep = - constG * mextern / dr
- ener = ek + ep
- tout(ifile) = time
- eout(*,ifile) = ener[0:nfollow-1]
- ekin(*,ifile) = ek[0:nfollow-1]
- epot(*,ifile) = ep[0:nfollow-1]
-endfor
-
-; calculate relative energy change
-de = 0.0 * eout
-for ifile=1, nfiles -1 do de[*,ifile] = (eout[*,ifile]-eout[*,0])/eout[*,0]
-
-
-end
-
-
diff --git a/examples/Makefile.am b/examples/Makefile.am
index 58dcc5ac2b45e567d3023303d2a588551a5cfcfd..dd13fb7eb4b82fbbfbb1ae450e20d01b13f2a455 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -63,7 +63,7 @@ EXTRA_DIST = BigCosmoVolume/makeIC.py \
EAGLE_12/eagle_12.yml EAGLE_12/getIC.sh EAGLE_12/README EAGLE_12/run.sh \
EAGLE_25/eagle_25.yml EAGLE_25/getIC.sh EAGLE_25/README EAGLE_25/run.sh \
EAGLE_50/eagle_50.yml EAGLE_50/getIC.sh EAGLE_50/README EAGLE_50/run.sh \
- ExternalPointMass/externalPointMass.yml ExternalPointMass/makeIC.py ExternalPointMass/run.sh ExternalPointMass/test.pro \
+ ExternalPointMass/externalPointMass.yml ExternalPointMass/makeIC.py ExternalPointMass/run.sh ExternalPointMass/energy_plot.py \
GreshoVortex_2D/getGlass.sh GreshoVortex_2D/gresho.yml GreshoVortex_2D/makeIC.py GreshoVortex_2D/plotSolution.py GreshoVortex_2D/run.sh \
HydrostaticHalo/README HydrostaticHalo/hydrostatic.yml HydrostaticHalo/makeIC.py HydrostaticHalo/run.sh \
HydrostaticHalo/density_profile.py HydrostaticHalo/velocity_profile.py HydrostaticHalo/internal_energy_profile.py HydrostaticHalo/test_energy_conservation.py \