The function provides efficient state-of-the-art random number generation of a vector of truncated univariate distribution
of the same length as the lower bound vector. The function is vectorized and the vector of means mu and
of standard deviations sd are recycled.
If mu or sd are not specified they assume the default values of 0 and 1, respectively.
Value
vector or matrix of random variates (rtnorm) or of quantiles (ptnorm), depending on the input