#14888: Make FiniteField_pari_ffelt the default for generic finite fields
-------------------------------------+-------------------------------------
Reporter: pbruin | Owner: cpernet
Type: enhancement | Status: needs_work
Priority: major | Milestone: sage-5.13
Component: finite rings | Resolution:
Keywords: FiniteField | Merged in:
performance | Reviewers: Jean-Pierre Flori,
Authors: Peter Bruin | Jeroen Demeyer
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: #12142, #15124, | Stopgaps:
#15125 |
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Comment (by jdemeyer):
Replying to [comment:32 pbruin]:
> > > In the line `ret = ret + c`, could you replace `c` by `base(c)`
> > With that change, I no longer get the error (which unfortunately
doesn't imply that the bug is fixed).
> Mysterious. I checked that the coercion system does exactly the same
thing internally
How did you check? I think it's more and more likely that the coercion
system is the problem here, because
1) The coercion system is notorious for generating hard-to-reproduce bugs
since it relies on (hashes of) memory addresses.
2) Making the conversions explicit (see diff below) fixes the problem.
{{{
#!diff
diff --git a/sage/libs/singular/singular.pyx
b/sage/libs/singular/singular.pyx
--- a/sage/libs/singular/singular.pyx
+++ b/sage/libs/singular/singular.pyx
@@ -232,9 +232,9 @@
c = <long>napGetCoeff(z)
e = napGetExpFrom(z,1, _ring)
if e == 0:
- ret = ret + c
+ ret = ret + base(c)
elif c != 0:
- ret = ret + c * a**e
+ ret = ret + (a**e) * base(c)
z = <napoly*>pNext(<poly*>z)
return ret
}}}
--
Ticket URL: <http://trac.sagemath.org/ticket/14888#comment:36>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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