Opened 7 years ago

Closed 7 years ago

# [with patch, positive review] Ideals in multivariate polynomial rings with no variables raise exception on comparison

Reported by: Owned by: broune broune major sage-3.0.2 commutative algebra multivariate polynomial ring, no variables

### Description

This code

ring = PolynomialRing?(QQ, names=[])

id = ring.ideal(0)

print id == id

gives the following error message

<type 'exceptions.StopIteration?'> Traceback (most recent call last)

/Users/bjarke/sync/<ipython console> in <module>()

/Users/bjarke/sync/element.pyx in sage.structure.element.Element.richcmp (sage/structure/element.c:4558)()

/Users/bjarke/sync/element.pyx in sage.structure.element.Element._richcmp (sage/structure/element.c:4453)()

/Users/bjarke/sage-3.0/local/lib/python2.5/site-packages/sage/rings/polynomial/multi_polynomial_ideal.py in cmp(self, other)

347 True
348 """

--> 349 l = self.groebner_basis()

350 r = other.groebner_basis()
351 return cmp(r,l)

/Users/bjarke/sage-3.0/local/lib/python2.5/site-packages/sage/rings/polynomial/multi_polynomial_ideal.py in groebner_basis(self, algorithm, *args, kwds)

1836 except TypeError?: # conversion to Singular not supported
1837 # we might want to print a warning here

-> 1838 gb = toy_buchberger.buchberger_improved(self, *args, kwds)

1839 elif algorithm.startswith('singular:'):
1840 gb = self._groebner_basis_using_singular(algorithm[9:])

/Users/bjarke/sage-3.0/local/lib/python2.5/site-packages/sage/rings/polynomial/toy_buchberger.py in buchberger_improved(F)

232 print "%d reductions to zero."%(reductions_to_zero)
233

--> 234 return Sequence(inter_reduction(G))

235
236 def update(G,B,h):

/Users/bjarke/sage-3.0/local/lib/python2.5/site-packages/sage/rings/polynomial/toy_buchberger.py in inter_reduction(Q)

324 Q -- a set of polynomials
325 """

--> 326 base_ring = iter(Q).next().base_ring()

327 Q = set(Q)
328 while True:

<type 'exceptions.StopIteration?'>:

### comment:1 Changed 7 years ago by broune

• Summary changed from Ideals in multivariate polynomial rings raise exceptions on comparison to Ideals in multivariate polynomial rings with no variables raise exception on comparison

### comment:2 Changed 7 years ago by broune

• Owner changed from malb to broune
• Status changed from new to assigned
• Summary changed from Ideals in multivariate polynomial rings with no variables raise exception on comparison to [with patch, needs review] Ideals in multivariate polynomial rings with no variables raise exception on comparison

### comment:3 Changed 7 years ago by cwitty

• Summary changed from [with patch, needs review] Ideals in multivariate polynomial rings with no variables raise exception on comparison to [with patch, positive review] Ideals in multivariate polynomial rings with no variables raise exception on comparison

Code looks good, doctests pass in sage/rings/polynomial. Positive review.

### comment:4 Changed 7 years ago by mabshoff

• Resolution set to fixed
• Status changed from assigned to closed

Merged in Sage 3.0.2.alpha0

Note: See TracTickets for help on using tickets.