#5963: 3.4.2.a0: prime_pi returns wrong results on some platforms for large
input
---------------------------+------------------------------------------------
Reporter: mabshoff | Owner: was
Type: defect | Status: new
Priority: major | Milestone: sage-3.4.2
Component: number theory | Keywords:
---------------------------+------------------------------------------------
Alex reports:
I can't get this to segfault. I tried on sage.math and on my laptop
(macbook running 32-bit archlinux). The problem is that the two machines
get different answers after a while (I hope the table is clear -- the last
column is a function that's "known" to be a good approximation to
prime_pi):
{{{
x prime_pi(x) on sage.math prime_pi(x) on my laptop
Li(x)-Li(sqrt(x))/2
2^46 2280998753949 2280998753949
2.28099863535e+12
2^47 4461632979717 4454203917918
4.46163280359e+12
2^48 8731188863470 8612800813048
8.73118897751e+12
2^49 17094432576778 15793194017311
1.70944327138e+13
2^50 33483379603407 21969300962685
3.34833795774e+13
}}}
So it seems that the problem starts somewhere between 2^46 and 2^47, and
that the sage.math output is most likely correct.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/5963>
Sage <http://sagemath.org/>
Sage - Open Source Mathematical Software: Building the Car Instead of
Reinventing the Wheel
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en
-~----------~----~----~----~------~----~------~--~---
