#12871: Conversion for RR[x][y] stricter than for QQ[x][y]
-----------------------------+----------------------------------------------
Reporter: vbraun | Owner: AlexGhitza
Type: PLEASE CHANGE | Status: new
Priority: major | Milestone: sage-5.1
Component: algebra | Keywords:
Work issues: | Report Upstream: N/A
Reviewers: | Authors:
Merged in: | Dependencies:
Stopgaps: |
-----------------------------+----------------------------------------------
The following works:
{{{
sage: R.<x,y> = QQ[]
sage: U = R.univariate_ring(x)
sage: U([y])
y
}}}
but over ``RR`` it does not:
{{{
sage: R.<x,y> = RR[]
sage: U = R.univariate_ring(x)
sage: U([y])
---------------------------------------------------------------------------
ValueError Traceback (most recent call
last)
/home/vbraun/<ipython console> in <module>()
/home/vbraun/opt/sage-5.0.beta13/local/lib/python2.7/site-
packages/sage/structure/parent.so in sage.structure.parent.Parent.__call__
(sage/structure/parent.c:7940)()
/home/vbraun/opt/sage-5.0.beta13/local/lib/python2.7/site-
packages/sage/structure/coerce_maps.so in
sage.structure.coerce_maps.DefaultConvertMap_unique._call_
(sage/structure/coerce_maps.c:3344)()
/home/vbraun/opt/sage-5.0.beta13/local/lib/python2.7/site-
packages/sage/structure/coerce_maps.so in
sage.structure.coerce_maps.DefaultConvertMap_unique._call_
(sage/structure/coerce_maps.c:3247)()
/home/vbraun/opt/sage-5.0.beta13/local/lib/python2.7/site-
packages/sage/rings/polynomial/polynomial_ring.pyc in
_element_constructor_(self, x, check, is_gen, construct, **kwds)
364 C = self._polynomial_class
365 if isinstance(x, list):
--> 366 return C(self, x, check=check,
is_gen=False,construct=construct)
367 if isinstance(x, Element):
368 P = x.parent()
/home/vbraun/opt/sage-5.0.beta13/local/lib/python2.7/site-
packages/sage/rings/polynomial/polynomial_element.so in
sage.rings.polynomial.polynomial_element.Polynomial_generic_dense.__init__
(sage/rings/polynomial/polynomial_element.c:38456)()
/home/vbraun/opt/sage-5.0.beta13/local/lib/python2.7/site-
packages/sage/structure/parent.so in sage.structure.parent.Parent.__call__
(sage/structure/parent.c:7940)()
/home/vbraun/opt/sage-5.0.beta13/local/lib/python2.7/site-
packages/sage/structure/coerce_maps.so in
sage.structure.coerce_maps.NamedConvertMap._call_
(sage/structure/coerce_maps.c:4298)()
/home/vbraun/opt/sage-5.0.beta13/local/lib/python2.7/site-
packages/sage/rings/polynomial/multi_polynomial.so in
sage.rings.polynomial.multi_polynomial.MPolynomial._polynomial_
(sage/rings/polynomial/multi_polynomial.c:3371)()
/home/vbraun/opt/sage-5.0.beta13/local/lib/python2.7/site-
packages/sage/rings/polynomial/multi_polynomial.so in
sage.rings.polynomial.multi_polynomial.MPolynomial.polynomial
(sage/rings/polynomial/multi_polynomial.c:5417)()
/home/vbraun/opt/sage-5.0.beta13/local/lib/python2.7/site-
packages/sage/structure/parent.so in sage.structure.parent.Parent.__call__
(sage/structure/parent.c:7940)()
/home/vbraun/opt/sage-5.0.beta13/local/lib/python2.7/site-
packages/sage/structure/coerce_maps.so in
sage.structure.coerce_maps.DefaultConvertMap_unique._call_
(sage/structure/coerce_maps.c:3344)()
/home/vbraun/opt/sage-5.0.beta13/local/lib/python2.7/site-
packages/sage/structure/coerce_maps.so in
sage.structure.coerce_maps.DefaultConvertMap_unique._call_
(sage/structure/coerce_maps.c:3247)()
/home/vbraun/opt/sage-5.0.beta13/local/lib/python2.7/site-
packages/sage/rings/polynomial/polynomial_ring.pyc in
_element_constructor_(self, x, check, is_gen, construct, **kwds)
416 if x.type() != 't_POL':
417 x = x.Polrev()
--> 418 return C(self, x, check, is_gen, construct=construct,
**kwds)
419
420 def is_integral_domain(self, proof = True):
/home/vbraun/opt/sage-5.0.beta13/local/lib/python2.7/site-
packages/sage/rings/polynomial/polynomial_real_mpfr_dense.so in
sage.rings.polynomial.polynomial_real_mpfr_dense.PolynomialRealDense.__init__
(sage/rings/polynomial/polynomial_real_mpfr_dense.c:3449)()
ValueError: max() arg is an empty sequence
}}}
This is the reason for the behavior observed in
http://ask.sagemath.org/question/1359/strange-error-with-multivariate-
polynomials
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12871>
Sage <http://www.sagemath.org>
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