On Tue, Jun 11, 2013 at 2:16 PM, Gilbert Gede <gilbertg...@gmail.com> wrote:
> Prasoon, > That option does not work for ReferenceFrame. If I have a ReferenceFrame > A, and another ReferenceFrame B, and want to set the angular velocity of B > in A as > w_1*b_1 + w_2_* b_2 + w_3 * b_3 > I need access to the basis vectors of B, which I won't have until after > the frame is initialized. Another situation that can occur is the angular > velocity being defined as: > w_1*b_1 + w_2_* b_2 + w_3 * b_3 + w_k * a_1 > I don't see any way around ReferenceFrame being mutable if you want to > maintain the same functionality that is in mechanics now. > As for having a separate CoordinateSystem and ReferenceFrame: I think it > is better to keep these explicit ideas separate if writing two classes > doesn't result in much code overlap. > Mutability makes me sad :-( I haven't read enough to comment on all of this any degree of intellect; I'm merely promoting principles. > Stefan, regarding your concerns about Vector eating everything up - isn't > that how it should be? Once you are dealing with Vectors, won't most > operations will result in a Vector? Matthew's suggestion to implement our > own VectorAdd/VectorMul seems like it might work though. > Also, is there a way to blacklist what functions are allowed to perform on > Vectors? > Blacklisting in inheritance is possible but apparently looked down upon. If you use Expr container classes (Add, Mul) it's likely that these methods will eventually be called upon in any event. http://stackoverflow.com/questions/16749312/remove-attribute-from-subclass-in-python -- 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.
