Hi Martin,
The corrected function would be
RANDU <- function(num) { return ((65539*num)%%(2^31)) }
You forgot the brackets for the return function.
Hence, what was returned was always (65539 * num)
On Mon, Aug 14, 2017 at 12:49 PM, Martin Møller Skarbiniks Pedersen
<traxpla...@gmail.com> wrote:
> Dear all,
>
> I am trying to learn functions in R and 3D plotting so I decided to try
> to plot
> the famous bad PRNG Randu from IBM(1).
> However something is not correct in the function I have created.
> First I define the function RANDU like this:
>
>> RANDU <- function(num) { return (65539*num)%%(2^31) }
>
> and test that it works for a seed of 1:
>> RANDU(1)
> [1] 65539
>
> but if I want the next value in the sequence I get this number.
>> (65539*65539)%%(2^31)
> [1] 393225
>
> However using the RANDU function twice doesn't give the same result as
> above.
>
>> RANDU(RANDU(1))
> [1] 4295360521
>
> I expect these two values to be the same but that is not the case.
> 393225 should be the correct.
>
> I guess it might be something with local vs. global environment ?!
>
> Please advise and thanks.
>
> Regards
> Martin M. S. Pedersen
>
> (1) https://en.wikipedia.org/wiki/RANDU
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
--
Huzefa Khalil
PhD Candidate,
Department of Political Science,
University of Michigan
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
