code: def _iter_qs(self):
          
          # work out how many Qs we need
          cumum = log(self.qrange[1] / self.qrange[0]) / 2**(1/2.)
          nplanes = int(max(ceil(cumum / self.deltam), 1))
          dq = cumum / nplanes  # pylint: disable=invalid-name
          for i in xrange(nplanes):
              yield self.qrange[0] * exp(2**(1/2.) * dq * (i + .5))
docs: Iterate over the Q values