Sachin put a link to this wikipedia article in the wiki: http://en.wikipedia.org/wiki/Frame_of_reference#Different_aspects_of_.22frame_of_reference.22 The way I have read the page is that coordinate systems should not change relative to the reference frame they are defined in; the conclusion I developed was that frames should be defined relative to each other and coordinate systems should be defined (and fixed) in frames. What are others' thoughts on this?
Stefan, If you have the same scalar field, written in a rectangular coordinate system as x * y * z and in a spherical coordinate system as r*sin(theta)*cos(phi) * r*sin(theta)*sin(phi) * r*cos(theta), and these two coordinate systems have the same orientation and origin, the scalar fields should be equivalent, right? Should they also evaluate as the same in SymPy? -Gilbert On Fri, Jun 7, 2013 at 5:15 AM, Stefan Krastanov <krastanov.ste...@gmail.com > wrote: > I have added more questions. I strongly dislike the separation between > CoordSys and RefFrame: such an abstraction is a nice idea, but the current > suggestion is very confusing and some parts of the definitions seem > unnecessary. > > At both of you: I still do not see why is there a need for ScalarField > class (some parts of you original suggestions require it (especially > Prasoon's), but I have explained on the page why I consider them a bad > idea). The need for such a class seems to be caused by lack of clarity on > how to specify what symbols correspond to coordinates in you > CoordSys/RefFrame/etc classes. > > > On 7 June 2013 13:48, Prasoon Shukla <prasoon92.i...@gmail.com> wrote: > >> @Everyone: >> >> I have added a separate heading towards the end of the wiki page. I would >> have done so yesterday but my internet had given up on me yesterday. >> >> Anyway, a few things I'd like to mention before you read it. >> First, I did not read the existing wiki page before adding content to it. >> This I primarily did so that I do not get influenced by the content already >> mentioned on the wiki page. I will read the existing page now and then we >> can work on merging the solutions that arise from the discussion. >> >> Second, I believe that there were quite a few confusions related to the >> working of the CoordSys class and the RefFrame class. I have tried to >> discuss that issue a bit as well. >> >> Then, I have tried providing a mock session as well. The point about >> Euler angles confused me so I have not incorporated that in the additions >> to the wiki page. >> @Stefan : Could you explain in a bit more detail how exactly is the frame >> C rotated *wrt* to frame A. If I understand Euler angles correctly, then >> two frames first need to be aligned and then rotation if performed on one >> of the frames. But in this case, frame A and C aren't aligned. So, what >> exactly does saying 'wrt A' mean in the present context? >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sympy" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to sympy+unsubscr...@googlegroups.com. >> To post to this group, send email to sympy@googlegroups.com. >> Visit this group at http://groups.google.com/group/sympy?hl=en-US. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sympy+unsubscr...@googlegroups.com. > To post to this group, send email to sympy@googlegroups.com. > Visit this group at http://groups.google.com/group/sympy?hl=en-US. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy?hl=en-US. For more options, visit https://groups.google.com/groups/opt_out.
