diff --git a/examples/adhesion.py b/examples/adhesion.py
index 35c6b25..491409e 100644
--- a/examples/adhesion.py
+++ b/examples/adhesion.py
@@ -1,120 +1,120 @@
 #!/usr/bin/env python3
 #
 # Copyright (©) 2016-2022 EPFL (École Polytechnique Fédérale de Lausanne),
 # Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as published
 # by the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU Affero General Public License for more details.
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 import tamaas as tm
 import matplotlib.pyplot as plt
 import numpy as np
 import argparse
 
 from matplotlib.colors import ListedColormap
 
 
 class AdhesionPython(tm.Functional):
     """
     Functional class that extends a C++ class and implements the virtual
     methods
     """
 
     def __init__(self, rho, gamma):
         tm.Functional.__init__(self)
         self.rho = rho
         self.gamma = gamma
 
     def computeF(self, gap, pressure):
         return -self.gamma * np.sum(np.exp(-gap / self.rho))
 
     def computeGradF(self, gap, gradient):
         gradient += self.gamma * np.exp(-gap / self.rho) / self.rho
 
 
 parser = argparse.ArgumentParser()
 parser.add_argument('--local-functional', dest="py_adh", action="store_true",
                     help="use the adhesion functional written in python")
 
 args = parser.parse_args()
 
 # Surface size
 n = 1024
 
 # Surface generator
 sg = tm.SurfaceGeneratorFilter2D([n, n])
-sg.random_seed = 0
+sg.random_seed = 1
 
 # Spectrum
 sg.spectrum = tm.Isopowerlaw2D()
 
 # Parameters
 sg.spectrum.q0 = 16
 sg.spectrum.q1 = 16
 sg.spectrum.q2 = 64
 sg.spectrum.hurst = 0.8
 
 # Generating surface
 surface = sg.buildSurface()
 surface /= n
 
 plt.imshow(surface)
 plt.title('Rough surface')
 
 # Creating model
 model = tm.ModelFactory.createModel(tm.model_type.basic_2d, [1., 1.], [n, n])
 
 # Solver
 solver = tm.PolonskyKeerRey(model, surface, 1e-12,
                             tm.PolonskyKeerRey.gap,
                             tm.PolonskyKeerRey.gap)
 adhesion_params = {
   "rho": 2e-3,
   "surface_energy": 2e-5
 }
 
 # Use the python derived from C++ functional class
 if args.py_adh:
     adhesion = AdhesionPython(adhesion_params["rho"],
                               adhesion_params["surface_energy"])
 # Use the C++ class
 else:
     adhesion = tm.ExponentialAdhesionFunctional(surface)
     adhesion.parameters = adhesion_params
 
 solver.addFunctionalTerm(adhesion)
 
 # Solve for target pressure
 g_target = 5e-2
 solver.solve(g_target)
 
 tractions = model.traction
 
 plt.figure()
 plt.imshow(tractions)
 plt.colorbar()
 plt.title('Contact tractions')
 
 plt.figure()
 zones = np.zeros_like(tractions)
 tol = 1e-6
 zones[tractions > tol] = 1
 zones[tractions < -tol] = -1
 plt.imshow(zones, cmap=ListedColormap(['white', 'gray', 'black']))
 plt.colorbar(ticks=[-2/3, 0, 2/3]).set_ticklabels([
     'Adhesion', 'No Contact', 'Contact'
 ])
 
 plt.title('Contact and Adhesion Zones')
 
 plt.show()
diff --git a/examples/rough_contact.py b/examples/rough_contact.py
index 079c2f2..21064f1 100644
--- a/examples/rough_contact.py
+++ b/examples/rough_contact.py
@@ -1,62 +1,62 @@
 #!/usr/bin/env python3
 #
 # Copyright (©) 2016-2022 EPFL (École Polytechnique Fédérale de Lausanne),
 # Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as published
 # by the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU Affero General Public License for more details.
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 import tamaas as tm
 import matplotlib.pyplot as plt
 
 # Initialize threads and fftw
 tm.set_log_level(tm.LogLevel.info)  # Show progression of solver
 
 # Surface size
 n = 512
 
 # Surface generator
 sg = tm.SurfaceGeneratorFilter2D([n, n])
-sg.random_seed = 0
+sg.random_seed = 1
 
 # Spectrum
 sg.spectrum = tm.Isopowerlaw2D()
 
 # Parameters
 sg.spectrum.q0 = 16
 sg.spectrum.q1 = 16
 sg.spectrum.q2 = 64
 sg.spectrum.hurst = 0.8
 
 # Generating surface
 surface = sg.buildSurface()
 surface /= tm.Statistics2D.computeSpectralRMSSlope(surface)
 
 plt.imshow(surface)
 
 # Creating model
 model = tm.ModelFactory.createModel(tm.model_type.basic_2d, [1., 1.], [n, n])
 
 # Solver
 solver = tm.PolonskyKeerRey(model, surface, 1e-12)
 
 # Solve for target pressure
 p_target = 0.1
 solver.solve(p_target)
 
 plt.figure()
 plt.imshow(model.traction)
 plt.title('Contact tractions')
 print(model.traction.mean())
 
 plt.show()
diff --git a/examples/statistics.py b/examples/statistics.py
index eebe552..af689f1 100644
--- a/examples/statistics.py
+++ b/examples/statistics.py
@@ -1,81 +1,81 @@
 #!/usr/bin/env python3
 #
 # Copyright (©) 2016-2022 EPFL (École Polytechnique Fédérale de Lausanne),
 # Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as published
 # by the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU Affero General Public License for more details.
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 import os
 
 import numpy as np
 import matplotlib.pyplot as plt
 import tamaas as tm
 
 from matplotlib.colors import LogNorm
 
 tm.set_log_level(tm.LogLevel.info)  # Show progression of solver
 
 # Surface size
 n = 512
 
 # Surface generator
 sg = tm.SurfaceGeneratorFilter2D([n, n])
-sg.random_seed = 0
+sg.random_seed = 1
 
 # Spectrum
 sg.spectrum = tm.Isopowerlaw2D()
 
 # Parameters
 sg.spectrum.q0 = 16
 sg.spectrum.q1 = 16
 sg.spectrum.q2 = 64
 sg.spectrum.hurst = 0.8
 
 # Generating surface
 surface = sg.buildSurface()
 
 # Computing PSD and shifting for plot
 psd = tm.Statistics2D.computePowerSpectrum(surface)
 psd = np.fft.fftshift(psd, axes=0)
 
-plt.imshow(psd.real, norm=LogNorm())
+plt.imshow(np.clip(psd.real, 1e-10, np.inf), norm=LogNorm())
 plt.gca().set_title('Power Spectrum Density')
 plt.gcf().tight_layout()
 
 # Computing autocorrelation and shifting for plot
 acf = tm.Statistics2D.computeAutocorrelation(surface)
 acf = np.fft.fftshift(acf)
 
 plt.figure()
 plt.imshow(acf)
 plt.gca().set_title('Autocorrelation')
 plt.gcf().tight_layout()
 plt.show()
 
 # Write the rough surface in paraview's VTK format
 try:
     import uvw
     try:
         os.mkdir('paraview')
     except FileExistsError:
         pass
     x = np.linspace(0, 1, n, endpoint=True)
     y = x.copy()
 
     with uvw.RectilinearGrid(os.path.join('paraview', 'surface.vtr'),
                              (x, y)) as grid:
         grid.addPointData(uvw.DataArray(surface, range(2), 'surface'))
 except ImportError:
     print("uvw not installed, will not write VTK file")
     pass