Opened 7 years ago

Closed 7 years ago

#17971 closed defect (fixed)

Infinite recursion when taking a resultant over a complicated base ring

Reported by: pbruin Owned by:
Priority: trivial Milestone: sage-6.7
Component: algebra Keywords: infinite recursion polynomial resultant
Cc: Merged in:
Authors: Peter Bruin Reviewers: Vincent Delecroix
Report Upstream: N/A Work issues:
Branch: 0983972 (Commits, GitHub, GitLab) Commit: 09839726d16ef06a51f8acda28aab00d04e4efb4
Dependencies: Stopgaps:

Status badges

Description (last modified by pbruin)

The following resultant computation used to lead to an infinite recursion before #17974 (merged in 6.7.beta0):

sage: A.<a,c> = Frac(PolynomialRing(QQ,'a,c'))
sage: B.<d,e> = PolynomialRing(A,'d,e')
sage: R.<x> = PolynomialRing(B,'x')
sage: (a*d*x^2+a+e+1).resultant(-4*c^2*x+1)
Traceback (most recent call last):
...
RuntimeError: maximum recursion depth exceeded while calling a Python object

Although this particular bug is now fixed, the doctest and the shortcut added by this ticket may still be useful.

Change History (8)

comment:1 Changed 7 years ago by pbruin

  • Authors set to Peter Bruin
  • Branch set to u/pbruin/17971-infinite_recursion
  • Commit set to da8ddc1c1e9b3f9867f0fe74beda90f16244b2b5
  • Description modified (diff)
  • Status changed from new to needs_review

comment:2 Changed 7 years ago by pbruin

  • Description modified (diff)

comment:3 Changed 7 years ago by git

  • Commit changed from da8ddc1c1e9b3f9867f0fe74beda90f16244b2b5 to 09839726d16ef06a51f8acda28aab00d04e4efb4

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

0983972Trac 17971: fix infinite recursion in FractionField_generic._element_constructor_()

comment:4 Changed 7 years ago by pbruin

  • Description modified (diff)

comment:5 Changed 7 years ago by pbruin

  • Priority changed from major to trivial

comment:6 Changed 7 years ago by vdelecroix

  • Reviewers set to Vincent Delecroix
  • Status changed from needs_review to positive_review

comment:7 Changed 7 years ago by vdelecroix

  • Milestone changed from sage-6.6 to sage-6.7

comment:8 Changed 7 years ago by vbraun

  • Branch changed from u/pbruin/17971-infinite_recursion to 09839726d16ef06a51f8acda28aab00d04e4efb4
  • Resolution set to fixed
  • Status changed from positive_review to closed
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