I built a bare-metal, zero-allocation QEC decoder in Rust (~400ns on 17x17 with p=0.001). It's fully open source.
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Hi everyone, I’ve been working on a project to solve what I think is one the biggest bottleneck in Fault-Tolerant Quantum Computing that I can tackle from my basement: Classical Control Latency. Most QEC decoders used in research are optimized for Code Distance or Thresholds, but they often run in high-level environments (Python/C++) with non-deterministic memory usage. That works for simulation, but it fails on real hardware where you have sub-microsecond deadlines before the qubits dephase. So I built prav-core. It’s a Union-Find decoder written in pure Rust. I built prav-core to strip the decoding process down to the physics. The Stack: Pure Rust (#![no_std]): Compiles to x86, ARM64, WASM, and bare-metal Cortex-R5. Zero Allocation: malloc is banned in the decode loop. We use a pre-allocated arena. Verified: Includes 39 Kani proofs covering memory safety and arena bounds. Algorithm: Union-Find with Morton (Z-order) encoding for cache locality. Preliminary Benchmarks: I'm seeing p50 latencies of 0.06µs (60ns) for 17x17 grids and 0.07µs for 22x22 grids at physical error rates of 0.001. Shape Dims p Avg (us) p50 (us) p99 (us) Square 17x17 0.001 0.39 0.06 2.20 Square 22x22 0.001 0.63 0.07 2.24 Square 32x32 0.001 4.39 5.97 10.32 The Roadmap: Python bindings are coming next (for easier comparison with PyMatching), but the end goal is to run Distance-25 codes in under 500ns on commodity FPGAs. It’s open source (Apache 2.0 / MIT). I'd love for people to try breaking it. Repo: https://github.com/qubitsok/prav Crate: https://crates.io/crates/prav-core I’d love to hear your thoughts on the architecture or if anyone has experience deploying Union-Find on embedded targets! submitted by /u/freechoice [link] [comments]