Opened 7 years ago
Closed 7 years ago
#14902 closed defect (duplicate)
Singular NULL pointer with a ring of the form QQ(t)[x, y]/(f)
Reported by: | pbruin | Owned by: | malb |
---|---|---|---|
Priority: | major | Milestone: | sage-duplicate/invalid/wontfix |
Component: | commutative algebra | Keywords: | Singular NULL pointer |
Cc: | Merged in: | ||
Authors: | Reviewers: | Jeroen Demeyer, Peter Bruin, Volker Braun | |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description (last modified by )
(Duplicate of #12188)
The following returns the right thing in the end, but exhibits a problem with calling Singular in the process:
sage: K.<t> = FunctionField(QQ) sage: A.<x,y> = PolynomialRing(K, 2) sage: B = A.quotient(y^2 + (t + 1)*x*y + t*y - x^3 - t*x^2) sage: B.gens() verbose 0 (3490: multi_polynomial_ideal.py, groebner_basis) Warning: falling back to very slow toy implementation. singular_ring_delete(ring*) called with NULL pointer. File "/home/staff/pbruin/src/sage-5.11.beta3/local/bin/sage-ipython", line 18, in <module> app.start() ... File "/home/staff/pbruin/src/sage-5.11.beta3/local/lib/python2.7/site-packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 910, in _groebner_strategy return GroebnerStrategy(MPolynomialIdeal(self.ring(), self.groebner_basis())) Exception KeyError: (The ring pointer 0x0,) in 'sage.libs.singular.ring.singular_ring_delete' ignored (xbar, ybar)
Probably Gröbner bases shouldn't even be invoked in this example, but that is another question.
Change History (6)
comment:1 Changed 7 years ago by
comment:2 Changed 7 years ago by
Volker says that this ask.sagemath question is a duplicate as well.
comment:3 Changed 7 years ago by
- Description modified (diff)
- Milestone changed from sage-5.12 to sage-duplicate/invalid/wontfix
- Status changed from new to needs_review
I posted a patch for #12188 that fixes this ticket as well. Now the output of the above example is
verbose 0 (3490: multi_polynomial_ideal.py, groebner_basis) Warning: falling back to very slow toy implementation. (xbar, ybar)
comment:4 Changed 7 years ago by
- Reviewers set to Volker Braun
- Status changed from needs_review to positive_review
I agree, same issue as #12188.
comment:5 Changed 7 years ago by
- Reviewers changed from Volker Braun to Jeroen Demeyer, Peter Bruin, Volker Braun
comment:6 Changed 7 years ago by
- Resolution set to duplicate
- Status changed from positive_review to closed
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Looks very much like #12188.