[Rd] RNG usability

Paul Gilbert pgilbert@bank-banque-canada.ca
Wed, 23 Feb 2000 14:40:24 -0500


I presume that I misunderstand something, but if I do not then I think
there is a serious problem for the way many people actually use RNGs
(rather than studying or testing them). To summarize the way I
understand the documentation and what you have said:

1/ Directly setting the .Random.seed is not something that users should
do and will not in the future be guaranteed to put the RNG into a state
that would reproduce a sequence of random numbers. Users should use
set.seed to put the RNG in a known state. (BTW, I was using my syskern
library version of set.seed before, which just set .Random.seed. Sorry
about the confusion.)

2/ set.seed takes only a single integer as an argument, so there is no
guaranteed way to query the state of the RNG at any given time, and then
reset it to that state at a later time.

If this second point is true, then I fear there is a serious problem.

Paul Gilbert

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