DiskSEISMIC v0.1.0 — SII + Disk-Resident Benchmarks

DiskSEISMIC: Disk-Resident Learned Sparse Retrieval via Global Block Ranking

This release adds the SII (Summary Inverted Index) algorithm and disk-resident benchmarking tools for SEISMIC.

Key Features

• SII algorithm: Global block ranking that replaces per-posting-list traversal with partial-sort-based top-K' block selection. Scores fewer documents at iso-recall (0.51–0.94×).
• Disk benchmark (sii_disk_bench): Cold-cache mmap comparison of SII vs SEISMIC with per-query cache eviction on EBS.
• RAM benchmark (sii_bench): In-memory SII vs SEISMIC sweep with iso-recall comparison tables.
• SII feasibility evaluator (sii_eval): Measures routing quality (recall vs K') for the global block ranking strategy.
• MmapForwardIndex: Memory-mapped forward index with batch prefetch for disk-resident scoring.
• CDC pre-filter, Early Exit, Skip-Singleton summaries, DocIdLookup: Supporting infrastructure from the SEISMIC-Disk research.

Results (MSMARCO v1, 8.8M docs, cold-cache EBS gp3)

Recall	SII latency	SEISMIC latency	Ratio
0.92	2,739 μs	3,337 μs	0.82×
0.95	4,732 μs	5,627 μs	0.84×
0.97	6,545 μs	9,767 μs	0.67×

Usage

cargo build --release --bin sii_bench --bin sii_disk_bench --bin sii_eval

# RAM benchmark
./target/release/sii_bench -i index.seismic -q queries.bin --gt gt.tsv

# Disk benchmark (cold-cache)
./target/release/sii_disk_bench -i index.seismic -q queries.bin --gt gt.tsv --flat-fi-path /tmp/fi.flat --cold --n-bench 6980