egglog VS mpack

The herbie project using egraphs to explore different ways of rewriting floating point expressions. https://herbie.uwplse.org/ One can also write custom rulesets in egglog (a new egraph rewriting system / language / datalog) https://egraphs-good.github.io/egglog/?example=herbie

The approach is not yet anywhere near being able to touch all the domains sympy can handle. Destructive term rewriting tends to be a bit more forgiving to unsoundness in the rules and still returning roughly meaningful results. EGraph rewriting (and other automated reasoning systems) tend to just return junk as soon as you aren't careful about your semantics. Associativity and commutativity are ubiquitous in CAS applications and encoding these concepts in general purpose terms is rather unsatisfying. The post above emphasizes specialty methods for polynomials, which it would be desirable to find a clean way to integrate into egraph techniques. Variable binding (which is treated in a rather mangled form in CAS systems) is seemingly important for treating summation, differentiation, and integration correctly. The status of doing variable binding efficiently and correctly in egraphs is also unclear imo.

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

The recent work on relational, datalog-inspired egraphs in PLDI this year ("Unifying Datalog and Equality Saturation") is actually interesting because it can solve cases like the y/x*x -> y identity example, by the power of an interval analysis on x (among other things.) Sort of like adding a postulate but instead it's by adding relations between terms in the graph.

https://github.com/egraphs-good/egglog

https://arxiv.org/pdf/2304.04332.pdf

Close, but the link is on Page 13, and it points here: https://github.com/mwillsey/egg-smol

Unfortunately the naming is all a bit confusing, isn't it....

I recently released a new version of my C MessagePack library MPack [1] with a cool new feature to dynamically calculate the size of maps and arrays during encoding. Having to always specify the size of containers up-front was a pain. I believe it's the only C/C++ MessagePack implementation that can do this. Of course bugs appeared immediately so I am working on a patch release.

I am also working on and off on my C template library Pottery [2]. I haven't pushed any code in a while; having a day job and young children makes progress slow :(

[1]: https://github.com/ludocode/mpack