#4622: certain input for variety() crashes Singular [reported upstream]
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Reporter: SimonKing | Owner: malb
Type: defect | Status: new
Priority: major | Milestone: sage-4.1.2
Component: commutative algebra | Keywords: variety triang.lib
Reviewer: | Author:
Merged: |
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Comment(by SimonKing):
Replying to [comment:3 malb]:
> This seems to be fixed in (at least) 4.1.1. Simon, can you confirm this?
With Sage 4.1, in the "simpler" example, I get
{{{
sage: sage: R.<w>= PolynomialRing(QQ,1)
sage: sage: H=w
sage: sage: I= ideal(H); I
Ideal (w) of Multivariate Polynomial Ring in w over Rational Field
sage: sage: I.variety()
verbose 0 (1744: multi_polynomial_ideal.py, variety) Warning: falling back
to very slow toy implementation.
[{w: 0}]
}}}
which seems to be correct, or at least it doesn't crash.
The original example works as well:
{{{
sage: R.<w,z>= PolynomialRing(QQ,2,order='lex')
sage: F= 19 -20*z -20*w +5*z^2 +14*z*w +5*w^2 -2*z^2*w -2*z*w^2 +z^2*w^2
sage: G= (w*z-1)*F
sage: I=ideal([G]+G.gradient())
sage: I=ideal(I.groebner_basis())
sage: I
Ideal (w^2 - 2*w - 17/5*z^4 + 434/25*z^3 - 817/25*z^2 + 672/25*z - 179/25,
w*z - w + 33/28*z^4 - 433/70*z^3 + 869/70*z^2 - 839/70*z + 641/140, z^5 -
27/5*z^4 + 56/5*z^3 - 56/5*z^2 + 27/5*z - 1) of Multivariate Polynomial
Ring in w, z over Rational Field
sage: I.variety()
[{z: 1, w: 1}]
}}}
So, yes, the crash seems fixed since at least Sage 4.1, probably when
Singular was upgraded.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/4622#comment:4>
Sage <http://sagemath.org/>
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