code: def prepare_ec(self, scaffolds, tour, weights):
          
          scaffolds_ii = dict((s, i) for i, s in enumerate(scaffolds))
          scfs = []
          ww = []
          for mlg in self.linkage_groups:
              w = float(weights[mlg.mapname])
              scf = {}
              for s, o in tour:
                  si = scaffolds_ii[s]
                  scf[si] = self.get_series(mlg.lg, s, orientation=o)
              scfs.append(scf)
              ww.append(w)
          tour = [scaffolds_ii[x] for x, o in tour]
  
          return scfs, tour, ww
docs: Prepare Evolutionary Computation. This converts scaffold names into
          indices (integer) in the scaffolds array.