On Thu, May 15, 2008 at 8:21 AM, Bjake Hammersholt Roune <[EMAIL PROTECTED]> wrote: > >> [...] people are confused that when >> they create a matrix with matrix(3, range(9)), for example, that the >> echelon_form is not the rref output that they get from most any other >> program they have ever used [...] >> What do people think about making the default ring for matrices QQ? >> > I have no objections to making QQ the defailt ring for matrices.
I do. That's definitely *not* the proposal. The proposal is to make the base ring the fraction field of the canonical ring in which the list of entries live, if that fraction field is defined. QQ was just an example. > However, I don't think this resolves the problem entirely. > > A part of the confusion stems from echelon_form doing entirely > different things based on the type of argument it gets. I would prefer > echelon_form to always use fractions, and have some other function > avoid the fractions. Another solution I could get behind is for > echelon_form to have a parameter for whether to use fractions, and > have the default be to use them. Echelon form over a field is just a natural special case of a more general notion of echelon forms over rings. So from an algebraist's point of view echelon form does *exactly* the same thing over ZZ or QQ, relative to the ring over which we are working. -- William --~--~---------~--~----~------------~-------~--~----~ 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://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
