Le 12/08/2013 12:19, Julien Puydt a écrit :
> Le 10/08/2013 22:16, Volker Braun a écrit :
>> Since the factorization starts with 2^64 it looks like there is
>> something wrong with how uint64_t is being used in the computation.
>> Possibly a 32-bit/64-bit problem.
>
> The following computation is even more interesting:
>
> sage: n=2^100-1;n
> 1267650600228229401496703205375
> sage: pari(n)
> 31668760015517046052350966685377757183
> sage: pari(n)
> 27806445565810435977365220706566012927
> sage: pari(n)
> 28935765463492261505845880393861955583
> sage: pari(n)
> 67017549253314407993604807848961769471
>
> I know the build is quite experimental, but this is off-limit: there's
> something extremely fishy being done!
>
> I see two possibilities: either something is using the clock to convert
> integers to integers, or some piece of code has been making evil things
> with the stack, and has been getting away with it until now by sheer luck!
>
> The second is my suspect...
If it had been a moving stack, I guess running the following several
times would have given a segfault:
for _ in range(1000):
for _ in range(1000):
pari(n)
since it didn't... I'm back to trying to understand what can happen...
Snark
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