— Function: unsigned int gsl_ran_logarithmic (const gsl_rng * r, double p)

This function returns a random integer from the logarithmic distribution. The probability distribution for logarithmic random variates is,

          p(k) = {-1 \over \log(1-p)} {(p^k \over k)}

for k >= 1.

— Function: double gsl_ran_logarithmic_pdf (unsigned int k, double p)

This function computes the probability p(k) of obtaining k from a logarithmic distribution with probability parameter p, using the formula given above.