Symbolics.jl VS AbstractDifferentiation.jl

It’s not up to parity with SymPy/Matlab by far yet - here’s the tracking issue on it https://github.com/JuliaSymbolics/Symbolics.jl/issues/59

Hello Juila Community. This is my second day working with Julia, having come over from Sympy due to performance reasons. I am working on a project that requires calculating matrix determinants and adjugates for families of matrices with symbolics entries. I am using Symbolics.jl for the symbols and using Juilia 1.8.2.

After spending some time reading the documentation, it turns out that JuliaSymbolics also lacks factorizations functionality (according to [Link](https://github.com/JuliaSymbolics/Symbolics.jl/issues/59))

You can also get an expression for the partial of β with respect to h using Symbolics.jl:

The example is applied to the right-hand side of a generated mass-matrix ODE (DAE) which is then solved using the adaptive time stepping methods of DifferentialEquations.jl. It's a test example that comes from the robotics / rigid body dynamics simulation groups (specifically interested in control) where they before were generating the governing equations with SymPy, and recently switched to try Symbolics.jl (and we got the example because of some performance issues that needed fixing). The comparison is with and without applying the code simplifier before solving. The table shows an average global induced error of 1e-12 when chopping off the 1e-11 * sin(x) terms and smaller. Thus there's nothing "competitive" against standard adaptive time stepping here: it's used to enhance the simulation of generated models that are simulated with the adaptive time steppers.

Done. https://github.com/JuliaSymbolics/Symbolics.jl/issues/215

A working common interface for all kinds of differentiation. Like AbstractDifferentiation.jl tries to do, but it is far from finished and seems unmaintained.

Yes there are 3-5 different automatic differentiation implementations focusing on different algorithms and types of codes to differentiate. However if such a circumstance are discovered the Julia community tends to jointly implement abstractions. The first one was chainrules which implement the rules for derivatives of mathematical functions (how to calculate the derivative of the gamma function) in a shared place. The next step is https://github.com/JuliaDiff/AbstractDifferentiation.jl which unifies the different algorithms.