[R-sig-hpc] Quick rsprng questions

[Thomas Hampton]

Hello Ross,

We recently installed rsprng on our beowulf cluster. My recollection  
was that
R routines like sample() gave weird results before we did this --  
namely,
you could sample as many times as you like and you would get the same  
result, as if
you were setting the seed to some fixed value (even when you did not).

I am not observing this behavior now.

My questions are these.

First, is it a normal feature of clusters to show odd random number  
properties if
you do not have something like rsprng in there?

Second, if you install rspring, does the problem just magically go  
away, or do you need
to make special calls in your R code to take advantage of rsprng?

Finally, why (roughly) is random number generation different in the  
parallel environment to begin with?

Thanks very much,

Tom