code: def to_log(x1, x2, x1err, x2err):
      
      logx1 = numpy.log10(numpy.array(x1))
      logx2 = numpy.log10(numpy.array(x2))
      x1err = numpy.log10(numpy.array(x1)+numpy.array(x1err)) - logx1
      x2err = numpy.log10(numpy.array(x2)+numpy.array(x2err)) - logx2
      return logx1, logx2, x1err, x2err
docs: Take linear measurements and uncertainties and transform to log values.