Quaternions with symbolic elements

I'm trying to create quaternion number that contains symbolic elements but Matlab throws an error.

syms a
d=quaternion(1,2,3,a)

This is the error I get

All inputs to the quaternion constructor must be the same class (double or
single).

[James Tursa]

What do you intend to do with these symbolic quaternions downstream in your code? It would be pretty easy to write your own basic functions such as add, subtract, multiply, conjugate, inverse, etc. But if you intend to convert them to other forms such as direction cosine matrix or Euler angles then you will run into major difficulties.

Answer 1

[Chris]

The error says it all. It looks like symbolic variables aren't supported for quaternions. You might try a third-party toolbox:

https://github.com/simonebri/msqt

Answer 2

[Bruno Luong]

Work around is use 2 x 2 (symboloc) complex matrix to do quaternion computation https://en.wikipedia.org/wiki/Quaternion#Matrix_representations