[Bug-gsl] gsl_rng_taus2 on 64-bit architecture

[John Gehman]

Hello gsl folks,

I've just pinned down the problem in porting my code from my i686 (32- 
bit) desktop to a x86_64 Blade. The problem was that I used  
gsl_rng_taus2; if I change this to gsl_rng_taus my code compiles and  
runs fine (he says without having actually tested the random number  
generation).

I presume this may not be so much a bug as an oversight. I note in the  
manual:

> "Note that the algorithm relies on the properties of 32-bit unsigned  
> integers and has been implemented using a bitmask of 0xFFFFFFFF to  
> make it work on 64 bit machines.
> ...
>
> The generator gsl_rng_taus2 uses the same algorithm as gsl_rng_taus  
> but with an improved seeding procedure ...
>
> The generator gsl_rng_taus2 should now be used in preference to  
> gsl_rng_taus."

I'm off my patch with respect to the inner workings of this, but I am  
naively guessing that the same (or an analogous) bitmask has not been  
implemented in the taus2 algorithm as for taus?

Kind Regards,
John


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John Gehman
ARC Future Fellow
School of Chemistry
Bio21 Institute
Univ. of Melbourne
VIC 3010 Australia
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