#9049: v4.4.1 bug in variety() over finite field extensions of Q?
----------------------------------+-----------------------------------------
Reporter: cynthia_vinzant | Owner: AlexGhitza
Type: defect | Status: new
Priority: major | Milestone:
Component: algebraic geometry | Keywords:
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
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I'm interested in computing the 0-dimensional variety of an ideal over
finite field extensions of Q. I've tried the following code both on my
copy (v4.4.1) of sage and online and it produces an error message. My
friend tried the same code on his v4.2 sage and it worked fine. Is it
possible there's a bug in the newer version?
{{{
S.<t>=PolynomialRing(QQ)
F.<q>=QQ.extension(t^4+1)
R.<x,y>=PolynomialRing(F)
I=R.ideal(x,y^4+1)
I.variety()
}}}
This produces the following error message:
Traceback (click to the left of this block for traceback)
...
ValueError: Length must be equal to the degree of this number field
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "_sage_input_11.py", line 10, in <module>
exec compile(u'open("___code___.py","w").write("# -*- coding: utf-8
-*-\\n" +
_support_.preparse_worksheet_cell(base64.b64decode("Uy48dD49UG9seW5vbWlhbFJpbmcoUVEpCkYuPHE+PVFRLmV4dGVuc2lvbih0XjQrMSkKUi48eCx5Pj1Qb2x5bm9taWFsUmluZyhGKQpJPVIuaWRlYWwoeCx5XjQrMSkKSS52YXJpZXR5KCk="),globals())+"\\n");
execfile(os.path.abspath("___code___.py"))
File "", line 1, in <module>
File "/tmp/tmpZcwb0q/___code___.py", line 7, in <module>
exec compile(u'I.variety()
File "", line 1, in <module>
File "/usr/local/sage2/local/lib/python2.6/site-
packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 407, in
__call__
return self.f(self._instance, *args, **kwds)
File "/usr/local/sage2/local/lib/python2.6/site-
packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 2094, in
variety
TI = self.triangular_decomposition('singular:triangLfak')
File "/usr/local/sage2/local/lib/python2.6/site-
packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 407, in
__call__
return self.f(self._instance, *args, **kwds)
File "/usr/local/sage2/local/lib/python2.6/site-
packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 901, in
triangular_decomposition
is_groebner = self.basis_is_groebner()
File "/usr/local/sage2/local/lib/python2.6/site-
packages/sage/misc/cachefunc.py", line 322, in __call__
return self._cachedmethod._instance_call(self._instance, *args,
**kwds)
File "/usr/local/sage2/local/lib/python2.6/site-
packages/sage/misc/cachefunc.py", line 466, in _instance_call
cache[key] = self._cachedfunc.f(inst, *args, **kwds)
File "/usr/local/sage2/local/lib/python2.6/site-
packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 1666, in
basis_is_groebner
F = matrix(R, 1, self.ngens(), self.gens())
File "/usr/local/sage2/local/lib/python2.6/site-
packages/sage/matrix/constructor.py", line 652, in matrix
return matrix_space.MatrixSpace(ring, nrows, ncols,
sparse=sparse)(entries)
File "/usr/local/sage2/local/lib/python2.6/site-
packages/sage/matrix/matrix_space.py", line 405, in __call__
return self.matrix(entries, copy=copy, coerce=coerce, rows=rows)
File "/usr/local/sage2/local/lib/python2.6/site-
packages/sage/matrix/matrix_space.py", line 1136, in matrix
return self.__matrix_class(self, entries=x, copy=copy, coerce=coerce)
File "matrix_generic_dense.pyx", line 68, in
sage.matrix.matrix_generic_dense.Matrix_generic_dense.__init__
(sage/matrix/matrix_generic_dense.c:1997)
File "multi_polynomial_libsingular.pyx", line 758, in
sage.rings.polynomial.multi_polynomial_libsingular.MPolynomialRing_libsingular.__call__
(sage/rings/polynomial/multi_polynomial_libsingular.cpp:7176)
File "parent.pyx", line 854, in sage.structure.parent.Parent.__call__
(sage/structure/parent.c:6332)
File "coerce_maps.pyx", line 82, in
sage.structure.coerce_maps.DefaultConvertMap_unique._call_
(sage/structure/coerce_maps.c:3108)
File "coerce_maps.pyx", line 77, in
sage.structure.coerce_maps.DefaultConvertMap_unique._call_
(sage/structure/coerce_maps.c:3010)
File "/usr/local/sage2/local/lib/python2.6/site-
packages/sage/rings/number_field/number_field.py", line 1023, in
_element_constructor_
raise ValueError, "Length must be equal to the degree of this number
field"
ValueError: Length must be equal to the degree of this number field
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9049>
Sage <http://www.sagemath.org>
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