#15710: sage hangs in division in cyclotomic field
---------------------------------+------------------------
Reporter: ppurka | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.1
Component: number fields | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
---------------------------------+------------------------
Description changed by jdemeyer:
Old description:
> From the [https://spreadsheets.google.com/pub?key=pCwvGVwSMxTzT6E2xNdo5fA
> google notebook bug reports]
> {{{
> # The computation of b below hangs.
>
> q=49
> F.<E>=CyclotomicField(q)
> G = F['z,w'].fraction_field()
> [z,w]=G.gens()
>
> denom = (E-E^22)*(E-E^27)
> print denom
> print
>
> recip=1/denom
> print recip
> print
>
> a=w*recip
> print a
> print
>
> b=w/denom
> print b
> print
>
> recip=1/denom
> print recip
> print
>
> a=w*recip
> print a
> print
>
> b=w/denom
> print b
> }}}
> ''The attempt to evaluate b=w/denom hangs. But the reciprocal of the
> denominator is not complicated: Sage has no trouble evaluating
> recip=1/denom and then a=w*recip.''
>
> ''Note that z is not involved in this computation, just in the definition
> in the field of rational functions.''
New description:
From the [https://spreadsheets.google.com/pub?key=pCwvGVwSMxTzT6E2xNdo5fA
google notebook bug reports]
The computation of b below hangs and cannot be interrupted.
{{{
q=49
F.<E>=CyclotomicField(q)
G = F['z,w'].fraction_field()
[z,w]=G.gens()
denom = (E-E^22)*(E-E^27)
print denom
print
recip=1/denom
print recip
print
a=w*recip
print a
print
b=w/denom
print b
print
}}}
The attempt to evaluate b=w/denom hangs. But the reciprocal of the
denominator is not complicated: Sage has no trouble evaluating
recip=1/denom and then a=w*recip.
Note that z is not involved in this computation, just in the definition in
the field of rational functions.
--
--
Ticket URL: <http://trac.sagemath.org/ticket/15710#comment:1>
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/groups/opt_out.
