[R] How to obtain seed after generating random number?

[Paul Gilbert]

It is nearly impossible to go back after the fact and figure out the
seed you started with. So, you need to be careful to record the seed
first. If you are doing your simulations with a function then it is a
good idea to always start in the function by saving a record of the seed
and returning it with the result. Then you always have the information
you need.

Beware that the seed is not the only thing you need to save. You also
need to record the uniform generator you are using, and the generator
for the distribution you are using. Of course, if you always only use
the default then you won't have a problem here, until the default
changes.

You might want to look at the utilities and examples in the package
setRNG.

Paul

>-----Original Message-----
>From: r-help-bounces at r-project.org
[mailto:r-help-bounces at r-project.org]
>On Behalf Of Bogaso Christofer
>Sent: August 24, 2010 1:12 PM
>To: r-help at r-project.org
>Subject: [R] How to obtain seed after generating random number?
>
>Dear all, I was doing an experiment to disprove some theory therefore
>performing lot of random simulation. Goal is to show the audience that
>although something has very rare chance to occur but it doesn't mean
>that
>event would be impossible.
>
>
>
>In this case after getting that rare event I need to show that same
>scenario
>for multiple times to explain other audience. Hence I need to somehow
>save
>that seed which generates that random numbers after doing the
>experiment.
>However as it is very rare event it is not very practical to start with
>a
>fixed seed and then generate random numbers. Hence I am looking for
some
>way
>which will tell me about that corresponding seed which was responsible
>to
>generate that particular series of random numbers responsible for
>occurrence
>of that rare event.
>
>
>
>In short, I need to know the seed ***after*** generating the random
>numbers.
>
>
>
>Is there any possibility to know this?
>
>
>
>Thanks and regards,
>
>
>	[[alternative HTML version deleted]]
>
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>PLEASE do read the posting guide http://www.R-project.org/posting-
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