runif().
set.resolution(resolution)NULL invisibly.
runif(). Generating a random number with the resolution 53 requires two iterations
of the internal 32 bit generator and
their outputs are combined to a single number. The slow down of 53 bit
resolution compared to 32 bit resolution is about 20 percent, since
an R call to runif() performs also other actions besides calling
the internal generator and these actions are run only once.