On Fri, May 23, 2008 at 9:40 AM, Jason Grout <[EMAIL PROTECTED]> wrote: > > Jason Grout wrote: >> In the recent discussion "Change the default base_ring for matrices from >> ZZ to QQ", there were lots of opinions shared, and William summarized >> some feelings from the group, but it wasn't a solid conclusion (at >> least, based on an IRC conversation, William is rethinking the conclusion). >> >> Here are two (somewhat competing) proposals, one from an IRC discussion >> with William just now and the other from William's summary from the >> previous thread. >> >> Proposal A: >> >> If a ring is not specified in a matrix() call, and the elements provided >> are all integers (or if there are no elements provided), then the base >> ring would default to QQ (instead of ZZ, as would currently happen). >> >> Reasons (from William and from discussions with a linear algebra person): >> >> 1. "linear algebra" is over fields (as opposed to module theory). When >> commonly-created matrices (i.e., ones with integer entries or with no >> specified entries) "default" to non-fields, the behavior is very >> surprising to linear algebra people and casual users (like linear >> algebra students, for example). >> >> 2. the matrix() command was designed for ease of use for "casual end users" >> >> 3. It is very easy to explicitly specify a ring, either in matrix() or >> via MatrixSpace >> >> >> So here are the cases we would see a change in behavior >> >> matrix(3,3) would return a 3x3 zero matrix over QQ instead of over ZZ >> >> matrix(3,range(9)) would return a 3x3 matrix over QQ instead of over ZZ. >> >> >> Proposal B (from William's summary on the previous thread): >> >> Leave matrix() as-is. Rename echelon_form to hermite_form, and make a >> new echelon_form function that computes hermite_form over the fraction >> field of the base ring. > > > It sounds like the popular vote selects proposal B. This is being > tracked at #3211. >
As BDFL (and person who supported A instead of B overall), and now agree that by popular vote we should do B. -- 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 -~----------~----~----~----~------~----~------~--~---
