#5252: elliptic curves: P.height() lies about its precision
---------------------------+------------------------------------------------
Reporter: AlexGhitza | Owner: was
Type: defect | Status: new
Priority: major | Milestone: sage-3.4.1
Component: number theory | Keywords:
---------------------------+------------------------------------------------
This is a bit weird because it seems to only happen with some elliptic
curves.
Anyway, here's the example:
{{{
sage: E = EllipticCurve([1, -1, 1, -2063758701246626370773726978,
32838647793306133075103747085833809114881])
sage: P = E([-30987785091199, 258909576181697016447])
sage: P.height() # default precision: 53 bits
sage: P.height(precision=100) # new precision: 100 bits
25.860317067546190744967149477
sage: P.height(precision=250) # new precision: 250 bits
25.860317067546190744967149477417933667311444878578186035156250000000000000
}}}
I don't believe for a second that all the zeroes in the last example are
correct. In fact, if you increase the precision to 1000 bits you only get
more zeroes.
There must be "simpler" elliptic curves for which this happens, and I'll
try to find some.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/5252>
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
-~----------~----~----~----~------~----~------~--~---
