The function for generating random sample or its name.
If distr is "rdist", the function "qdist" must be the quantile
function of this distribution with argument p as a vector of
probabilities, as all univariates distributions of the stat
library.
nsv
The number of raws of the final matrix.
nsu
The number of columns of the final matrix
nvariates
The number of variates
...
All arguments to be passed to distr except the
size of the sample.
