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
Attachment:
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. vito.trianni@(no_spam)istc.cnr.it
CNR-ISTC
http://laral.istc.cnr.it/trianni
via San Martino della Battaglia, 44
00185 Roma Tel: +39 06 44595 215
Italy Fax: +39 06 44595 243
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