#13308: eigenspaces_left sometimes raises an error while the documentation sais
it
should work.
-----------------------------------+----------------------------------------
Reporter: mderickx | Owner: jason, was
Type: defect | Status: needs_review
Priority: major | Milestone: sage-5.3
Component: linear algebra | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers: Maarten Derickx
Authors: Daniel Smertnig | Merged in:
Dependencies: | Stopgaps:
-----------------------------------+----------------------------------------
Description changed by mderickx:
Old description:
> See the following example
>
> {{{
> sage: M = ModularSymbols(Gamma1(23), sign=1)
> sage: m=M.cuspidal_subspace().hecke_matrix(2)
> sage: m.eigenspaces_left()
> ---------------------------------------------------------------------------
> ValueError Traceback (most recent call
> last)
>
> /Applications/sage-5.1.rc1/<ipython console> in <module>()
>
> /Applications/sage-5.1.rc1/local/lib/python2.7/site-
> packages/sage/matrix/matrix2.so in
> sage.matrix.matrix2.Matrix.eigenspaces_left
> (sage/matrix/matrix2.c:24746)()
>
> /Applications/sage-5.1.rc1/local/lib/python2.7/site-
> packages/sage/rings/polynomial/polynomial_element.so in
> sage.rings.polynomial.polynomial_element.Polynomial.root_field
> (sage/rings/polynomial/polynomial_element.c:24559)()
>
> /Applications/sage-5.1.rc1/local/lib/python2.7/site-
> packages/sage/rings/number_field/number_field.pyc in
> NumberField(polynomial, name, check, names, cache, embedding, latex_name,
> assume_disc_small, maximize_at_primes)
> 422 return NumberFieldTower(polynomial, name,
> embeddings=embedding)
> 423
> --> 424 name = sage.structure.parent_gens.normalize_names(1, name)
> 425
> 426 if not isinstance(polynomial, polynomial_element.Polynomial):
>
> /Applications/sage-5.1.rc1/local/lib/python2.7/site-
> packages/sage/structure/parent_gens.so in
> sage.structure.parent_gens.normalize_names
> (sage/structure/parent_gens.c:2204)()
>
> /Applications/sage-5.1.rc1/local/lib/python2.7/site-
> packages/sage/structure/parent_gens.so in
> sage.structure.parent_gens._certify_names
> (sage/structure/parent_gens.c:1761)()
>
> ValueError: variable names must be alphanumeric, but one is 'aa0 + 3'
> which is not.
> }}}
>
> In this example m is a matrix with rational coefficients. So according to
> the documentation this should just work.
New description:
See the following example
{{{
sage: M = ModularSymbols(Gamma1(23), sign=1)
sage: m=M.cuspidal_subspace().hecke_matrix(2)
sage: m.eigenspaces_left()
---------------------------------------------------------------------------
ValueError Traceback (most recent call
last)
/Applications/sage-5.1.rc1/<ipython console> in <module>()
/Applications/sage-5.1.rc1/local/lib/python2.7/site-
packages/sage/matrix/matrix2.so in
sage.matrix.matrix2.Matrix.eigenspaces_left
(sage/matrix/matrix2.c:24746)()
/Applications/sage-5.1.rc1/local/lib/python2.7/site-
packages/sage/rings/polynomial/polynomial_element.so in
sage.rings.polynomial.polynomial_element.Polynomial.root_field
(sage/rings/polynomial/polynomial_element.c:24559)()
/Applications/sage-5.1.rc1/local/lib/python2.7/site-
packages/sage/rings/number_field/number_field.pyc in
NumberField(polynomial, name, check, names, cache, embedding, latex_name,
assume_disc_small, maximize_at_primes)
422 return NumberFieldTower(polynomial, name,
embeddings=embedding)
423
--> 424 name = sage.structure.parent_gens.normalize_names(1, name)
425
426 if not isinstance(polynomial, polynomial_element.Polynomial):
/Applications/sage-5.1.rc1/local/lib/python2.7/site-
packages/sage/structure/parent_gens.so in
sage.structure.parent_gens.normalize_names
(sage/structure/parent_gens.c:2204)()
/Applications/sage-5.1.rc1/local/lib/python2.7/site-
packages/sage/structure/parent_gens.so in
sage.structure.parent_gens._certify_names
(sage/structure/parent_gens.c:1761)()
ValueError: variable names must be alphanumeric, but one is 'aa0 + 3'
which is not.
}}}
In this example m is a matrix with rational coefficients. So according to
the documentation this should just work.
Apply [attachment:trac_13308_eigenspaces_fix-review.patch] to the Sage
library.
--
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13308#comment:4>
Sage <http://www.sagemath.org>
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