Tweak file saving of NEBM to be sequential alphabetically on filesystems by prefixing with leading zeros

Author: rpep

fidimag/common/chain_method_base.py

@@ -348,7 +348,7 @@ def save_VTKs(self, coordinates_function=None):
 
         """
         # Create the directory
-        directory = 'vtks/%s_%d' % (self.name, self.iterations)
+        directory = "vtks/{}_{:05d}".format(self.name, self.iterations)
         self.VTK.directory = directory
 
         self.band.shape = (self.n_images, -1)