LLM-NTT Examples

This repository explores hardware design choices for N=512 negacyclic polynomial multiplication with near-full-range signed 32-bit coefficients and outputs modulo 2^32. NGen generates NTT products; SGen generates FFT products. The current centerpiece is a pre-route grid search that checks complete-product RTL, measures coarse Yosys resources, and compares arithmetic error, latency, and sustained frame interval. It does not claim U280 utilization or timing.

Start with the combined NGen/SGen frontier and its per-configuration table. The checked-in evidence contains 40 NGen and 6 SGen screened configurations, with separate columns for backend, lanes, PE count, radix, reduction algorithm, transpose boundary, precision, and approximation controls. The full RTL hashes and source campaign identities remain in the machine-readable CSV and JSON.

• architecture_search/: workload contract, generators, RTL construction, independent oracles, numerical analysis, and source identity checks.
• scripts/: NGen/SGen campaigns, common Yosys pass, reports, and build tools.
• apptainer/: the small pinned pre-route runtime image definition.
• docs/: experiment instructions and checked-in measured evidence.
• tests/python/: retained model and report tests.
• third_party/: pinned NGen, SGen, AutoNTT, and TFHEpp submodules.

Historical experiments and implementations remain recoverable from Git history.

The polynomial multiplication studies expand the comparison to full-width, byte, and ternary operands, FFT precision and digit omissions, NTT architectures, and separate output-rounding controls. Start with python3 scripts/polynomial_study.py --dry-run; the default specification is studies/torus512.json. New evidence is written to ignored build directories. For a bounded 12-configuration demonstration with the same validation pipeline, run scripts/run_polynomial_study.sh --spec studies/torus-demo.json --output-dir build/polynomial-study-demo. The completed results tables and tradeoff plots include all 171 qualified N=512 designs and all 12 demo designs, with CSV snapshots. The full-throughput FFT extension adds two/four-lane FFT designs at N=512; its separate campaign and merged reporting are described in the study guide.

From the repository root, with Apptainer, sbt, and native build dependencies:

scripts/build_generators.sh
scripts/build_assurance_yosys.sh
scripts/build_fhe512_image.sh
scripts/run_fhe512_preroute.sh --n 16 --bound 7 \
  --output-dir build/fhe512-smoke
scripts/run_fhe512_preroute.sh --grid covering --n 512 \
  --output-dir build/fhe512-covering-new
python3 scripts/report_fhe512_preroute.py \
  --output-dir build/fhe512-covering-new

The N=16 run checks the toolchain quickly. N=512 synthesis is much slower, especially for stage-parallel designs; interrupt and restart a campaign with --resume. The NGen campaign guide describes the grid controls. The SGen guide covers FFT precision and omitted digit products. The combined frontier guide explains the matched Yosys pass and how its historical source RTL is identified.

Run the retained Python checks with python3 -m unittest discover -s tests/python -q. The checked-in snapshots are evidence from completed campaigns, while new runs write to ignored build/ directories.