Function builtin_dgeom 

fn builtin_dgeom(
    args: &[RValue],
    named: &[(String, RValue)],
) -> Result<RValue, RError>

Geometric density (probability mass) function.

dgeom(x, prob) = prob * (1-prob)^x (number of failures before first success)

@param x quantile vector (non-negative integers) @param prob probability of success @return numeric vector of probabilities