# generate random numbers of Lévy distribution

I am going to generate a random step length which is drawn from a Lévy distribution $$\textrm{Lévy } \sim u= t^{-\lambda},\;\; 1<λ ≤3$$ How to (in computer) generate $$u$$ of such probability?

The formula comes from "Firefly Algorithm, Lévy Flights and Global Optimization" by Xin-She Yang. I have looked through other papers such as "Lévy Flight Trajectory-Based Whale Optimization", but none of them explained the processes to generate such random numbers.