#17088: PeriodicRegion.__div__: use integer arithmetic
-----------------------------------+------------------------
Reporter: jdemeyer | Owner:
Type: defect | Status: new
Priority: critical | Milestone: sage-6.4
Component: elliptic curves | Resolution:
Keywords: | Merged in:
Authors: Jeroen Demeyer | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
-----------------------------------+------------------------
Description changed by jdemeyer:
Old description:
> Replace the unreliable floating-point arithmetic of
> `PeriodicRegion.__div__` in
> `src/sage/schemes/elliptic_curves/period_lattice_region.pyx` by pure
> integer arithmetic.
>
> Note that I don't understand the purpose of the code, I just want to fix
> the fact that the results are not reproducible.
>
> == Background ==
> this is causing doctest failures in #16938 due to slightly different
> floating-point rounding. The failure is the following:
> {{{
> sage -t src/sage/schemes/elliptic_curves/period_lattice_region.pyx
> **********************************************************************
> File "src/sage/schemes/elliptic_curves/period_lattice_region.pyx", line
> 395, in
> sage.schemes.elliptic_curves.period_lattice_region.PeriodicRegion.__div__
> Failed example:
> (S / 3).plot()
> Expected:
> Graphics object consisting of 109 graphics primitives
> Got:
> Graphics object consisting of 121 graphics primitives
> **********************************************************************
> }}}
> (this output of `plot()` commands was added by #16746). As you can see,
> there are more pixels in the debug version.
New description:
Replace the unreliable floating-point arithmetic of
`PeriodicRegion.__div__` in
`src/sage/schemes/elliptic_curves/period_lattice_region.pyx` by pure
integer arithmetic to avoid floating-point rounding issues.
Note that I don't understand the purpose of the code, I just want to fix
the fact that the results are not reproducible.
== Background ==
this is causing doctest failures in #16938 due to slightly different
floating-point rounding. The failure is the following:
{{{
sage -t src/sage/schemes/elliptic_curves/period_lattice_region.pyx
**********************************************************************
File "src/sage/schemes/elliptic_curves/period_lattice_region.pyx", line
395, in
sage.schemes.elliptic_curves.period_lattice_region.PeriodicRegion.__div__
Failed example:
(S / 3).plot()
Expected:
Graphics object consisting of 109 graphics primitives
Got:
Graphics object consisting of 121 graphics primitives
**********************************************************************
}}}
(this output of `plot()` commands was added by #16746). As you can see,
there are more pixels in the debug version.
--
--
Ticket URL: <http://trac.sagemath.org/ticket/17088#comment:3>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-trac.
For more options, visit https://groups.google.com/d/optout.
