add example of using Cole-Cole model

user_libs/DebyeFit/Debye_Fit.py

@@ -180,6 +180,9 @@ class Relaxation(object):
         self.rl, self.im = q.real, q.imag
         
         if self.number_of_debye_poles == -1:
+            print("\n#########",
+                  "Try to automaticaly fit number of Debye poles, up to 20!",
+                  "##########\n", sep="")
             error = np.infty # artificial best error starting value
             self.number_of_debye_poles = 1
             iteration = 1

user_libs/DebyeFit/example_ColeCole.py

@@ -0,0 +1,43 @@
+# I. Giannakis, A. Giannopoulos and N. Davidson,
+# "Incorporating dispersive electrical properties in FDTD GPR models
+# using a general Cole-Cole dispersion function," 
+# 2012 14th International Conference on Ground Penetrating Radar (GPR), 2012, pp. 232-236
+
+from Debye_Fit import HavriliakNegami
+
+if __name__ == "__main__":
+    # set Havrilak-Negami function with initial parameters
+    setup = HavriliakNegami(f_min=1e4, f_max=1e11,
+                            alpha=0.3, beta=1,
+                            e_inf=3.4, de=2.7, tau_0=.8e-10,
+                            sigma=0.45e-3, mu=1, mu_sigma=0,
+                            material_name="dry_sand", f_n=100,
+                            plot=True, save=False,
+                            optimizer_options={'swarmsize':30,
+                                               'maxiter':100,
+                                               'omega':0.5,
+                                               'phip':1.4,
+                                               'phig':1.4,
+                                               'minstep':1e-8,
+                                               'minfun':1e-8,
+                                               'seed': 111,
+                                               'pflag': True})
+    ### Dry Sand in case of 3, 5
+    # and automatically set number of Debye poles (-1)
+    for number_of_debye_poles in [3, 5, -1]:
+        setup.number_of_debye_poles = number_of_debye_poles
+        setup.run()
+
+    ### Moist sand
+    # set Havrilak-Negami function parameters
+    setup.material_name="moist_sand"
+    setup.alpha = 0.25
+    setup.beta = 1
+    setup.e_inf = 5.6
+    setup.de = 3.3
+    setup.tau_0 = 1.1e-10,
+    setup.sigma = 2e-3
+    # calculate for different number of Debye poles
+    for number_of_debye_poles in [3, 5, -1]:
+        setup.number_of_debye_poles = number_of_debye_poles
+        setup.run()

user_libs/DebyeFit/optimization.py

@@ -97,6 +97,8 @@ class Optimizer(object):
             x (array): The number of current iterations.
             y (array): The objective value at for all x points.
         """
+        # it clears an axes
+        plt.cla()
         plt.plot(x, y, "b-", linewidth=1.0)
         plt.ylim(min(y) - 0.1 * min(y),
                  max(y) + 0.1 * max(y))