code: @Pure
      public static double random(double mu, double scale) throws MathException {
          return StochasticGenerator.generateRandomValue(new LogisticStochasticLaw(mu, scale));
      }
docs: Replies a random value that respect
  the current stochastic law.
  
  @param mu is the location of the distribution
  @param scale is the scale of the distristibution ({@code &gt;0})
  @return a value depending of the stochastic law parameters
  @throws MathException when error in math definition.