On Friday, June 14, 2013 3:39:20 PM UTC+5:30, Sachin Joglekar wrote: > > Also, Gilbert and I had a small question. How do you plan to implement > expression of Vectors in different frames? Also, the relationships between > the frames? Could you give an API and the basic idea of how those methods > will work? > The main concern the mechanics group has, is the modeling of relationships > among frames themselves, and those with vectors. Clearing up this part > would make things much clearer. >
Again, I really do not see what is so confusing. I'll try to be clear this time. Each vector has an attribute, `ref_frame`, which specifies the frame in which the vector has been defined in. As for relationship between the frames are concerned, we would have methods defined inside the RefFrame class that would output the transform matrices when required explicitly. Or, when required implicitly, the matrices would just be used up internally. For example, let us have a simple example. We have two frames A and B. Both in rectangular coordinates. B is rotated about the common x axis of both the frames by theta. Now, let us say the user just wants to know the conversion matrix. He can just do something like: B.convert_mat(A) And we would output transformation matrix. This stuff is just like mechanics. Let us add a bit more detail. Say the B frame is in spherical coordinates. Then, the transform matrix will also include the transform matrix from spherical to rectangular coordinates in the matrix product. Now, let us see how it would be used internally by the VectAdd and VectMul classes. Let us say we have a vector in some reference frame. Then, if we want to express that vector in another frame, we would do: vector.convert_to(ref_frame=frame) which returns a new vector. I hope that clarifies the issue of how things would work. More questions? -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. For more options, visit https://groups.google.com/groups/opt_out.
