Update python scripts to calculate field in the surroundings of a nanoshell.

tests/python/field.py

@@ -50,7 +50,7 @@ m = np.ones((1, 2), dtype = np.complex128)
 m[0, 0] = 1.53413/1.3205
 m[0, 1] = (0.565838 + 7.23262j)/1.3205
 
-npts = 101
+npts = 501
 
 scan = np.linspace(-4.0*x[0, 1], 4.0*x[0, 1], npts)
 
@@ -87,12 +87,12 @@ try:
     scale_y = np.linspace(min(coordY), max(coordY), npts)
 
     # Define scale ticks
-    min_tick = max(0.5, min(min_tick, np.amin(edata)))
+    min_tick = max(0.01, min(min_tick, np.amin(edata)))
     max_tick = max(max_tick, np.amax(edata))
     scale_ticks = np.power(10.0, np.linspace(np.log10(min_tick), np.log10(max_tick), 6))
 
     # Interpolation can be 'nearest', 'bilinear' or 'bicubic'
-    cax = ax.imshow(edata, interpolation = 'bicubic', cmap = cm.afmhot,
+    cax = ax.imshow(edata, interpolation = 'nearest', cmap = cm.afmhot,
                     origin = 'lower', vmin = min_tick, vmax = max_tick,
                     extent = (min(scale_x), max(scale_x), min(scale_y), max(scale_y)),
                     norm = LogNorm())
@@ -111,9 +111,11 @@ try:
 
     s1 = patches.Arc((0, 0), 2.0*x[0, 0], 2.0*x[0, 0], angle=0.0, zorder=2,
                       theta1=0.0, theta2=360.0, linewidth=1, color='#00fa9a')
-    s1 = patches.Arc((0, 0), 2.0*x[0, 1], 2.0*x[0, 1], angle=0.0, zorder=2,
-                      theta1=0.0, theta2=360.0, linewidth=1, color='#00fa9a')
     ax.add_patch(s1)
+
+    s2 = patches.Arc((0, 0), 2.0*x[0, 1], 2.0*x[0, 1], angle=0.0, zorder=2,
+                      theta1=0.0, theta2=360.0, linewidth=1, color='#00fa9a')
+    ax.add_patch(s2)
     # End of drawing
 
     plt.draw()