Stop hand-rolling GPU kernels for batch cosine similarity — use ggml (the
MIT-licensed compute library underneath llama.cpp, installed standalone via
Homebrew) as the preferred backend, without ripping out PR #114's
carefully-verified hand-rolled Metal shader.
Structure: one stable public adapter (eg_cosine_batch.h, zero #ifdef at call
sites) backed by three selectable concrete Strategies behind an internal
vtable (eg_cosine_batch_strategy.h) chosen by a Factory (eg_cosine_batch.c):
- eg_cosine_batch_strategy_ggml.c — NEW. ggml + dynamically-loaded Metal
backend plugin (ggml_backend_load_all_from_path
+ ggml_mul_mat for the batched dot
product), gather/scatter around the
-2.0 sentinel contract.
- eg_cosine_batch_strategy_metal_hand.m — PR #114's original hand-rolled
Metal shader bridge, preserved
almost verbatim, now one strategy
among several rather than the only
option. eg_cosine_batch.metal kept
byte-identical to the original.
- eg_cosine_batch_strategy_cpu.c — universal always-false fallback
(direct descendant of PR #114's
eg_metal_cosine_stub.c).
Selection: EL_COSINE_BATCH_STRATEGY=ggml|metal|cpu|auto (default: ggml first,
then hand-rolled Metal, then CPU — first available wins), plus back-compat
EL_METAL_COSINE=0 to disable every GPU-backed strategy. build_vindex_bench.sh
compiles all three strategies on Darwin, CPU-fallback-only elsewhere.
vindex_bench.c now reports BRUTE-GGML and BRUTE-METAL side by side against
the same CPU oracle, on the same dataset, in one run (real numbers vs. real
store snapshot in the PR body).
Adds an O(1) "seen" bitmap so lazily-embedded older nodes get picked up
incrementally instead of only on a full rebuild (embed-gap #20).
Replaces engram_activate's O(N*D) cosine prescan with a lazy-memoized
cosine cache (eg_cosq_at), proven bit-identical to the old path.
Extracts a clean vindex_harvest_from_store primitive (read-only vector
harvest, careful malloc/ownership/error-path handling) reused by both
index-build and the new vindex_bench.c — a read-only proof harness
comparing brute-force vs HNSW recall/latency on both the real store and
synthetic data.
.nsbx-env intentionally excluded — local sandbox config (ports, paths,
dev-only placeholder key), not checked in.
bigmerge