Yuriy Skalko

Ivar, I tested it only on simple expressions. Can you give some matrix example that breaks after this commit?

So this is because `*` means normal or matrix multiplication depending on argument types. It is not very convenient for symbolic computations, but cannot be changed. Another symbolic math software...

I think we should restrict to real numbers only. Anyway now all functions in the package don't support matrix/vector arguments. For example with matrices even diff(x_x, x) will be not...

@ivarne, now there are no dotted `*` and `^` in package source code. Is it justified enough to complicate code with matrix operations usage? I'm not sure. In my view...