Hi, On Thu, Jul 9, 2009 at 5:24 PM, luisfe<lftab...@yahoo.es> wrote: > > Hi, > > Some days ago I sent a bug report using the notebook link to the > google docs > form. I am unable to find that bug report on the web. > > Anyway as the thing is trivial I wrote a patch myself. > > The problem is that multivariate polynomials do not admit numerator > and > denominator > > sage: K.<x,y>=QQ['x,y'] > sage: f=x+y > sage: numerator(f) > --------------------------------------------------------------------------- > AttributeError Traceback (most recent call > last) > > /home/luisfe/.sage/temp/mychabol/5681/ > _home_luisfe__sage_init_sage_0.py in > <module>() > > /opt/SAGE/sage/local/lib/python2.5/site-packages/sage/misc/ > functional.pyc in > numerator(x) > 686 if isinstance(x, (int, long)): > 687 return x > --> 688 return x.numerator() > 689 > 690 def numerical_approx(x, prec=None, digits=None): > > AttributeError: 'sage.rings.polynomial.multi_polynomial_libsingular' > object > has no attribute 'numerator' > > > Although numerator and denominator are expectoed for rational > functions only > they might be needed, once would like to write an algorithm valid for > both > polynomials and rational functions, for example the following code in > the same > session: > > sage: g=y > sage: h=1-y > sage: (f/(g)).numerator() > x + y > sage: (f/(g+h)).denominator() > --------------------------------------------------------------------------- > AttributeError Traceback (most recent call > last) > > /home/luisfe/.sage/temp/mychabol/5681/ > _home_luisfe__sage_init_sage_0.py in > <module>() > > AttributeError: 'sage.rings.polynomial.multi_polynomial_libsingular' > object > has no attribute 'denominator' > > In the first case, the fraction is created and the numerator has a > meaning. In > the second the fraction is never created and the code fails. > > I have writen a trivial patch for the class MPolynomial. I am not sure > if > denominator should return 1 or self.parent(one) I write 1 because it > seems > inoffensive to me > > diff -r 2e793d2a0e12 sage/rings/polynomial/multi_polynomial.pyx > --- a/sage/rings/polynomial/multi_polynomial.pyx Thu Jun 18 > 23:52:34 > 2009 -0700 > +++ b/sage/rings/polynomial/multi_polynomial.pyx Thu Jul 09 > 00:05:29 > 2009 -0700 > @@ -980,6 +980,28 @@ > from sage.structure.factorization import Factorization > return Factorization(v, unit) > > + def numerator(self): > + """ > + Numerator of a polynomial > + > + EXAMPLES: > + sage: K.<x,y> = QQ['x,y'] > + sage: f = x + y > + sage: f.numerator() > + x + y > + """ > + return self > + > + def denominator(self): > + """ > + Denominator of a polynomial > + EXAMPLES: > + sage: K.<x,y> = QQ['x,y'] > + sage: f = x + y > + sage: f.denominator() > + 1 > + """ > + return 1 > > > cdef remove_from_tuple(e, int ind):
Thank you for reporting this. You can track this issue at ticket #6496 http://trac.sagemath.org/sage_trac/ticket/6496 -- Regards Minh Van Nguyen --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
