I would expect the Quaternions to automatically simplify to normal form. On Friday, August 4, 2017 at 2:06:30 PM UTC-5, Aaron Meurer wrote: > > What level of symbolics would you expect from the module? Would you expect > to be able to represent something like i*j unevaluated, or should every > quaternion automatically simplify itself to normal form a*i + b*j + c*k + d? > > Aaron Meurer > > On Fri, Aug 4, 2017 at 2:02 PM, Nikhil Pappu <nkhl...@gmail.com > <javascript:>> wrote: > >> Thanks for the reply Ondřej. I will look into Julia's implementation. I >> think that is a good place to start. I will eventually try to implement a >> lot more though. I am looking towards a Quaternion Algebra submodule. >> I found one such module in Sage so I guess that might be a good reference >> as well. >> >> On Friday, August 4, 2017 at 12:23:38 PM UTC-5, Ondřej Čertík wrote: >>> >>> Hi Nikhil, >>> >>> On Fri, Aug 4, 2017 at 8:12 AM, Nikhil Pappu <nkhl...@gmail.com> wrote: >>> > I was able to find some support for Quaternion Rotation in the Vector >>> module >>> > but I did not come across a general submodule on Quaternions which >>> allows >>> > users to define them and work with them. >>> > I would like to implement a submodule which can support Quaternion >>> > Arithmetic, Functions, Quaternion Calculus, Rotation conversions etc. >>> > It can then be extended to support more advanced Quaternion Algebra. >>> > >>> > Would it be a good idea for me to start working on this? >>> >>> >>> I think that would be useful. I was just looking for such a module few >>> days ago. You should look into how Julia does it: >>> >>> https://github.com/JuliaGeometry/Quaternions.jl >>> >>> Looks like they represent a quaternion a+bi+cj+dk as a tuple of of >>> coefficients (a, b, c, d) and they also store a flag if the norm can >>> be computed (it seems). >>> >>> Here I wrote code to multiply quaternions: >>> >>> >>> https://gitlab.com/certik/ijk/blob/df5f961d1f0432449fd7f16d21fa14840eef8c72/mul.py >>> >>> >>> I used complex 2x2 matrices. But Julia simply computes the new >>> coefficients (a, b, c, d) directly: >>> >>> >>> https://github.com/JuliaGeometry/Quaternions.jl/blob/62200f0ac5efd6d4d042f5d778d0cf2856c38c50/src/Quaternion.jl#L88 >>> >>> >>> That's probably the way to go. >>> >>> Ondrej >>> >> -- >> 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+un...@googlegroups.com <javascript:>. >> To post to this group, send email to sy...@googlegroups.com <javascript:> >> . >> Visit this group at https://groups.google.com/group/sympy. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/sympy/f0b5dcbe-6a3c-4d36-8e0c-e6f7c9de2d1d%40googlegroups.com >> >> <https://groups.google.com/d/msgid/sympy/f0b5dcbe-6a3c-4d36-8e0c-e6f7c9de2d1d%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> >> For more options, visit https://groups.google.com/d/optout. >> > >
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