On 5/14/07, Martin Albrecht <[EMAIL PROTECTED]> wrote: > > On Monday 14 May 2007 15:00, Michel wrote: > > Assuming all this is correct then I can see > > > > > why Martin is objecting to the docstring's vagueness, but AFAIK the > > > behavior is correct. > > > > Yes I now thinks so too. > > Please excuse my ignorance, but is this definition well known or should it be > given in the docstring? Also, how did the idea came up that SAGE needs this > method? I am just curious and trying to learn what people use MPolynomials > for.
I think the docstrings should be readable, informative and describe unambiguously what the implemented method does. Based on the example sage: R = PolynomialRing(QQ,2,'xy') sage: x,y = R.gens() sage: f = y^2 - x^9 - 7*x*y^2 + 5*x*y sage: f.coefficient(x*y) 5 sage: f.coefficient(x*y^2) -7 sage: f.coefficient(y) 5*x sage: f.coefficient(x) 5*y - 7*y^2 I think a monomial m(x,y) "exactly divides" f(x,y) means that m(x,y)|f(x,y) and neither x*m(x,y) or y*m(x,y) divides f(x,y). Generally speaking, such coefficient methods are extremely useful when trying to convert a linear algebra problem in a polynomial basis into a linear algebra problem involving matrices. For a specific example, the computation of the Duursma zeta polynomial P(T) of a linear code is a specific univariate polynomial which arises in a certain multivariate polynomial identity in three variables. To read off the coefficients of P you need to solve some simple equations obtained from coefficients of some multivariate polynomials. ++++++++++++++++++++++++++++++++++++++++++++ > > Martin > > -- > name: Martin Albrecht > _pgp: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x8EF0DC99 > _www: http://www.informatik.uni-bremen.de/~malb > _jab: [EMAIL PROTECTED] > > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
