Symbolics.jl VS egg

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

Maybe program optimization?

https://egraphs-good.github.io/

For semantic analyzers, check out egg and egglog. They're custom data structures for representing compiler rewrite rules in a non-destructive way.

E-graphs are pretty awesome, and worth keeping in your back pocket. They're like union-find structures, except they also maintain congruence relations (i.e. if `x` and `y` are in the same set, then `f(x)` and `f(y)` must likewise be in the same set).

https://egraphs-good.github.io/

(Incidentally, union-find structures are also great to know about. But they're not exactly "new".)

I would add that Equality saturation/E-graphs has become quite a hot topic recently, since their POPL21 paper, with workshops dedicated to applications of e-graphs. They have even recently been added to Cranelift as an IR for optimizations.

Egraphs solve the rewrite ordering problem quite nicely. https://egraphs-good.github.io/

Note that one solution to this problem is to use equality saturation (which, coincidentally, has a great implementation in rust!).

Have you thought about trying to parallelize e-graphs? This way you can do a bunch of rewrite rules in parallel and then extract your desired graph at the end instead of having conflicts.

I think the equality saturation papers are a good start. A good start is egg. They have a presentation, a research paper and code you can play with. I think ultimately you want to translate arithmetic operations into logical operation that can be understood by the fpga. So I think it would be good to research how adders and multipliers are implemented in logic and ultimately include equalities between adders/multipliers with their logical counterpart. Note the this translation also depends on the representations of your numbers and their bit width.

For rewriting, you may also find interesing equality saturation: https://egraphs-good.github.io/