code: func Logspace(lo, hi float64, num int, base float64) []float64 {
  	res := Linspace(lo, hi, num)
  	for i, x := range res {
  		res[i] = math.Pow(base, x)
  	}
  	return res
  }
docs: // Logspace returns num values spaced evenly on a logarithmic scale
  // between base**lo and base**hi, inclusive.