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Meta open-sources its nine-year-old assignment solver, Rebalancer

engineering.fb.com 8 min read Editor score 7/10

Rebalancer separates assignment specification, memory representation, solving, and debugging, and has been used at Meta for more than nine years. That separation is useful when evaluating optimization libraries for resource-allocation workloads.

What
Rebalancer is Meta’s open-sourced assignment-problem solver, used for resource allocation across its infrastructure.
How
It models objects, bins, constraints, and objectives, then converts specifications into an expression graph for local search or MIP.
Why it matters
Separating problem specification, storage, solving, and debugging aims to improve usability, scalability, and extensibility.
transforms designs builds solved with specificationlanguage expression graph local searchheuristic mixed integerprogram HiGHS
Rebalancer turns assignment specifications into a graph used to build a heuristic or MIP. Sketched from the article's own text.

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