@rnd_geometric(p:int)
P(i | p) = p (1 - p)^i, i ≥ 0.
See @rnd_bernoulli for a description of random generators.
See also Random Generators @rand @rand_int @random @rnd_bernoulli @rnd_binomial @rnd_exponential @rnd_gamma @rnd_geometric @rnd_normal @rnd_uniform_float @rnd_uniform_int