Opened 6 years ago

Last modified 5 years ago

#14624 new defect

Failure in Singular upon division with remainder for a multivariate polynomial ring over a univariate fraction field

Reported by: nthiery Owned by: malb
Priority: major Milestone: sage-6.4
Component: commutative algebra Keywords:
Cc: SimonKing Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description

sage: M = PolynomialRing(QQ['a'].fraction_field(), ['x','y'])
sage: x,y = M.gens()
sage: a = M(M.base_ring().gen())
sage: a.quo_rem(x)
Traceback (most recent call last):
...
/opt/sage-5.10.beta2/local/lib/python2.7/site-packages/sage/interfaces/singular.pyc in eval(self, x, allow_semicolon, strip, **kwds)
    588 
    589         if s.find("error") != -1 or s.find("Segment fault") != -1:
--> 590             raise SingularError('Singular error:\n%s'%s)
    591 
    592         if get_verbose() > 0:

TypeError: Singular error:
   ? division(`number`,`poly`) failed
   ? error occurred in or before STDIN line 101850: `def sage38517=division(sage38515,sage38516);`

Change History (7)

comment:1 Changed 6 years ago by nthiery

  • Cc SimonKing added

comment:2 Changed 6 years ago by SimonKing

First question: Why is this operation using the singular pexpect interface, and not libsingular?

Second question: Why is a._singular_init_() returning "a" and not "poly(a)" or so? As a result, we have

sage: M = PolynomialRing(QQ['a'].fraction_field(), ['x','y'])
sage: x,y = M.gens()
sage: a = M(M.base_ring().gen())
sage: singular(a).typeof()
number
sage: singular("a").typeof()
number
sage: singular("poly(a)").typeof()
poly

comment:3 Changed 6 years ago by SimonKing

I guess we have to look at sage.rings.polynomial.polynomial_singular_interface._singular_init_func, where the use of the string representation without adding "poly(...)" is hardcoded.

comment:4 Changed 6 years ago by jdemeyer

  • Milestone changed from sage-5.11 to sage-5.12

comment:5 Changed 5 years ago by vbraun_spam

  • Milestone changed from sage-6.1 to sage-6.2

comment:6 Changed 5 years ago by vbraun_spam

  • Milestone changed from sage-6.2 to sage-6.3

comment:7 Changed 5 years ago by vbraun_spam

  • Milestone changed from sage-6.3 to sage-6.4
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