NoSyu wrote: > Ah... message is gone, so I write again. OTL... > > > > > I solve the Linear Algebra course problems on Sage. > > Now I get the nullity of matrix to use nullity function, but it's > weird. > > > If I get the nullity of matrix A to use nullity function like that, > > A.nullity() > > but the result of this is same as left nullity of A.
You did a great job tracking this down. You're right; nullity in Sage refers to left nullity (i.e., dealing with vectors on the left, like v*M). You're also correct that this is different than most standard linear algebra, where the term "nullity" means "right nullity". This is a historical thing in Sage that unfortunately, at least at this point, is not going to change. Rather, Sage provides the explicit functions "right_nullity" and "left_nullity". We encourage you to use "right_nullity" or "left_nullity" to make it clear which nullity you are talking about. Eventually (not in the near future), the "nullity" function may be deprecated and no longer available, as it is ambiguous, or at least confusing. The Sage decision is not right or wrong; it's just a different convention. Moving to more explicit functions (left_nullity and right_nullity) is better, as it makes sure that everyone understands exactly what you mean. Jason --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
