Dear Eric, I cannot fully follow your argumentation:
i) Do you want to use random numbers based on a distribution provided by the GSL ii) Do you want to build a certain distribution on your own and then draw random numbers from it? In the first case, you initialise a random number generator provided by the GSL and call a certain function which provides random numbers according the distribution you prefer. In the second case you need to know the probability density function (pdf) or the cumulative distribution function (cdf) of the distribution you want to simulate. Then by applying the inverse transform you can transform uniformly distributed random numbers from the GSL to random numbers distributed according to your distribution. What do you want to achieve? Cheers, -- Klaus.