id,summary,reporter,owner,description,type,status,priority,milestone,component,resolution,keywords,cc,work_issues,upstream,reviewer,author,merged,dependencies,stopgaps
5080,"[with new patch, with positive review] Bug in decomposing modular symbol subspace",robertwb,davidloeffler,"{{{
sage: E = EllipticCurve(""128a"") 
sage: E.congruence_number()
------------------------------------------------------------
Traceback (most recent call last):
  File ""<ipython console>"", line 1, in <module>
  File ""/Users/robert/sage/sage-3.1.3/local/lib/python2.5/site-packages/sage/schemes/elliptic_curves/ell_rational_field.py"", line 2618, in congruence_number
    self.__congruence_number = W.congruence_number(V)
  File ""/Users/robert/sage/sage-3.1.3/local/lib/python2.5/site-packages/sage/modular/modsym/space.py"", line 938, in congruence_number
    W = other.q_expansion_module(prec, ZZ)
  File ""/Users/robert/sage/sage-3.1.3/local/lib/python2.5/site-packages/sage/modular/modsym/space.py"", line 770, in q_expansion_module
    return self._q_expansion_module_integral(prec)
  File ""/Users/robert/sage/sage-3.1.3/local/lib/python2.5/site-packages/sage/modular/modsym/space.py"", line 910, in _q_expansion_module_integral
    V = self.q_expansion_module(prec, QQ)
  File ""/Users/robert/sage/sage-3.1.3/local/lib/python2.5/site-packages/sage/modular/modsym/space.py"", line 772, in q_expansion_module
    return self._q_expansion_module_rational(prec)
  File ""/Users/robert/sage/sage-3.1.3/local/lib/python2.5/site-packages/sage/modular/modsym/space.py"", line 861, in _q_expansion_module_rational
    return self._q_expansion_module(prec)
  File ""/Users/robert/sage/sage-3.1.3/local/lib/python2.5/site-packages/sage/modular/modsym/space.py"", line 820, in _q_expansion_module
    return A.span([f.padded_list(prec) for f in self.q_expansion_basis(prec, algorithm)])
  File ""/Users/robert/sage/sage-3.1.3/local/lib/python2.5/site-packages/sage/modular/modsym/space.py"", line 602, in q_expansion_basis
    return Sequence(self._q_expansion_basis_hecke_dual(prec), cr=True)
  File ""/Users/robert/sage/sage-3.1.3/local/lib/python2.5/site-packages/sage/modular/modsym/space.py"", line 1073, in _q_expansion_basis_hecke_dual
    v = [self.dual_hecke_matrix(n).column(i) for n in range(1,prec)]
  File ""/Users/robert/sage/sage-3.1.3/local/lib/python2.5/site-packages/sage/modular/hecke/module.py"", line 797, in dual_hecke_matrix
    T = self._compute_dual_hecke_matrix(n)
  File ""/Users/robert/sage/current/local/lib/python2.5/site-packages/sage/modular/hecke/submodule.py"", line 110, in _compute_dual_hecke_matrix
    return A.restrict(self.dual_free_module(), check=check)
  File ""/Users/robert/sage/current/local/lib/python2.5/site-packages/sage/modular/hecke/submodule.py"", line 320, in dual_free_module
    ""(cut down to rank %s, but should have cut down to rank %s).""%(V.rank(), self.rank())
RuntimeError: Computation of embedded dual vector space failed (cut down to rank 9, but should have cut down to rank 8).
}}}",defect,closed,blocker,sage-4.1,modular forms,fixed,,craigcitro,,,"Craig Citro, Michael Abshoff, John Cremona",David Loeffler,sage-4.1.alpha0,,