Thanks to reply my message. I understand it.
You're right. From now, I use explicit function likes right_nullity. I learned right nullity convention, so rank + nullity = number of columns. I discuss about it with my Prof. Thanks again. Have a nice weekend.^^ ------------------------------------------------------------------------ 누구나가 다, 자기 옆에서 눈물을 흘리며 신음하는 불행한 사람들에 비해 자기가 훨씬 더 불행하다고 생각하지요. 이게 바로 우리 가련한 인간들의 오만 중의 하나입니다. - 몬테크리스토 백작 it is the infirmity of our nature always to believe ourselves much more unhappy than those who groan by our sides! - The Count of Monte Cristo c'est un des orgueils de notre pauvre humanité, que chaque homme se croie plus malheureux qu'un autre malheureux qui pleure et qui gémit à côté de lui - Le Comte de Monte-Cristo 박진영 - Bak Jin Yeong 학부재학생 - Undergraduate 컴퓨터공학전공 - Department of Computer Engineering 정보통신공학부 - School of Information & Communication Engineering 성균관대학교 - SungKyunKwan University 블로그 - http://nosyu.pe.kr 이메일 - don...@skku.edu On 5월15일, 오전11시43분, Jason Grout <jason-s...@creativetrax.com> wrote: > 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 -~----------~----~----~----~------~----~------~--~---
