# Manipulation of matrix symbols

**URL:** <https://discourse.julialang.org/t/manipulation-of-matrix-symbols/22526>\
**Category:** General Usage\
**Created:** [March 30, 2019, 7:17am UTC](https://discourse.julialang.org/t/manipulation-of-matrix-symbols/22526 "2019-03-30T07:17:17Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![baggepinnen](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/baggepinnen/32/693_2.png) [@baggepinnen](https://discourse.julialang.org/u/baggepinnen)\
**Post date:** [March 30, 2019, 7:17am UTC](https://discourse.julialang.org/t/manipulation-of-matrix-symbols/22526/1 "2019-03-30T07:17:17Z")

</div>

I have several times found myself wanting a package that can perform symbolic manipulations on matrix level. Many of the symbolic packages out there support creating matrices of symbols and using these in expressions ([SymPy for example](https://github.com/JuliaPy/SymPy.jl/blob/master/examples/tutorial.md#matrices)), the result of which becomes hard to parse as they are printed on the level of individual matrix entries. As an example, I would like to be able to do stuff like

```julia
A = SymMatrix(3,3)
v = SymVector(3)
A*v # stored/printed as Av
(2A)*(2v) # stored/printed as 4Av
v*A # error, dimensions don't match
[A A] # printed as [A A] 

R = SymMatrix(SO(3))
simplify(R'R) == I 

```

Is such functionality available in any of the julia symbolic libraries? If not, is any of these libraries exposing an abstract symbol type that I could extend and endow with size properties etc. to build up such functionality?