Re: [Bug-gsl] initialisation of random number generator on 64bit machine

[Vito Trianni]

Please find attached an example program that reproduces the error I  
was experiencing. I tested it on both 32- and 64-bit architectures,  
and it actually does not produce random values on the latter (see the  
"local" values in the last line of output: it varies across different  
runs on 32-bit architectures, but it does not on 64-bit ones).
Let me know if I can help more.
Regards,
Vito

bug-gsl.cpp
Description: Binary data

On Sep 5, 2008, at 6:22 PM, Brian Gough wrote:

> At Wed, 03 Sep 2008 15:43:33 +0200,
> Vito Trianni wrote:
> > Hello,
> > I noticed the following behaviour when initialising the random number
> > generator on a 64bit machine. Basically, on a 64 bit machine, the
> > unsigned long int probably provokes an overflow in the gsl_rng_set()
> > function, so that the initialisation of the seed in some way fails,  
> > and
> > I got always identical numbers despite different seeds. Here is  
> > part of
> > the code that made the overflow:
>
> Thanks for your email -- could you send a complete example program
> showing the seed and output values so we can reproduce the
> problem. Thank you.
>
> --
> Brian Gough
>
> GNU Scientific Library -
> http://www.gnu.org/software/gsl/

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Vito Trianni, Ph.D.                                     
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