Implement addition and subtraction between TensorValue and SymTensorValue

[ericneiva]

Implements missing addition and subtraction between TensorValue and SymTensorValue types (+ tests).

[codecov-commenter]

Codecov Report

Merging #755 (94b6cb8) into master (69cfe62) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #755      +/-   ##
==========================================
+ Coverage   88.32%   88.35%   +0.02%     
==========================================
  Files         152      152              
  Lines       16595    16595              
==========================================
+ Hits        14658    14662       +4     
+ Misses       1937     1933       -4     

Impacted Files	Coverage Δ
src/TensorValues/Operations.jl	90.23% <100.00%> (+1.18%)	⬆️

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[amartinhuertas]

Hi @ericneiva ! Do you plan to use symmetric tensors in gridap ? I have explored their usage in gridaphybrid and detected several bugs that I have fixed there temporarily but I might expedite fixing them in gridap if you are going to need them.

[ericneiva]

Hi, @amartinhuertas!

Yes, I am already using them on a driver which solves the linear elasticity problem on a 2-manifold. It requires subtracting symmetric and non-symmetric tensors. After this PR, I can integrate the weak form and everything appears to work.

I just have one question: Do any of these bugs provoke that your hybrid methods do not converge at the expected rate? If not, I'd say I do not depend on your fixes in the short-medium term.

Thanks a lot for your message 🙂

[amartinhuertas]

There are a number of bugs. E.g. interpolation of analytical function inside Fe space

Here are the fixes fyi

https://github.com/gridap/GridapHybrid.jl/blob/main/src/tmp_fixes_symmetric_valued_lagrangian_reffes.jl

[ericneiva]

It appears those fixes do not affect my results... for now.

I'll take a closer look later to double-check.

Thanks again, @amartinhuertas!