On Thu, May 15, 2008 at 7:48 AM, Jason Grout <[EMAIL PROTECTED]> wrote: > > Jason Grout wrote: >> Based on some conversations with linear algebra people and classroom >> demonstrations in a linear algebra class, 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, and certainly not what is taught in an >> undergrad linear algebra class. There is additional confusion if the >> entries specified have a fraction in them; then the matrix defaults to >> being over QQ, and the echelon_form functino gives the expected naive >> rref! The problem, of course, lies in the matrix defaulting to having >> base_ring == ZZ (i.e., non-field). >> >> >> What do people think about making the default ring for matrices QQ? >> Additionally, if the ring R is determined from the elements provided, >> then the matrix would be over R.fraction_field(). Of course, the >> documentation for matrix() would clearly indicate what is happening if >> the ring is not specified. >> > > > More concisely, this proposal could be worded: > > What do people think of making matrix() return a matrix over a field by > default, unless a ring is explicitly specified. The default field would > either be the fraction field of the ring containing the specified > elements, or would be QQ if no elements are specified. This logic would > *only* be applied if a ring is not specified. The documentation of > matrix() would also be changed accordingly. >
+1 I suggested this idea. I would never do this is Sage were "just for me", but Sage isn't. Please keep that in mind when reading the above proposal... -- 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 -~----------~----~----~----~------~----~------~--~---
