Hi, While working with number fields, I've run into this:
sage: K.<a> = NumberField(x^8+1) sage: R = K.polynomial_quotient_ring() sage: r = R.random_element() And now the point of this: I would like to think of r as an element of K. However: sage: K(r) --------------------------------------------------------------------------- TypeError Traceback (most recent call last) /opt/sage-3.2.1/devel/sage-main/sage/<ipython console> in <module>() /opt/sage-3.2.1/local/lib/python2.5/site-packages/sage/structure/parent.so in sage.structure.parent.Parent.__call__ (sage/structure/parent.c:3645)() /opt/sage-3.2.1/local/lib/python2.5/site-packages/sage/structure/coerce_maps.so in sage.structure.coerce_maps.DefaultConvertMap_unique._call_ (sage/structure/coerce_maps.c:2778)() /opt/sage-3.2.1/local/lib/python2.5/site-packages/sage/structure/coerce_maps.so in sage.structure.coerce_maps._call_ (sage/structure/coerce_maps.c:2685)() /opt/sage-3.2.1/local/lib/python2.5/site-packages/sage/rings/number_field/number_field.pyc in _element_constructor_(self, x) 1422 raise ValueError, "vector must be of length equal to the degree of this number field" 1423 return sum([ x[i]*self.gen(0)**i for i in range(self.degree()) ]) -> 1424 return self._coerce_non_number_field_element_in(x) 1425 1426 def _coerce_from_str(self, x): /opt/sage-3.2.1/local/lib/python2.5/site-packages/sage/rings/number_field/number_field.pyc in _coerce_non_number_field_element_in(self, x) 1520 except (TypeError, AttributeError), msg: 1521 pass -> 1522 raise TypeError, type(x) 1523 1524 def _coerce_map_from_(self, R): TypeError: <class 'sage.rings.polynomial.polynomial_quotient_ring_element.PolynomialQuotientRingElement'> Since K and R are canonically isomorphic, it seems to me that K(r) should really work. Any thoughts? Is there another way I can get r into K? Best, Alex -- Alex Ghitza -- Lecturer in Mathematics -- The University of Melbourne -- Australia -- http://www.ms.unimelb.edu.au/~aghitza/ --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
