feat(agent): new stores default to float16 embeddings

MemoryConfig::float16 now defaults to true for new stores, on measurement: on the full LongMemEval haystack with real MiniLM embeddings every retrieval metric matched f32 (previous commit), and at 100K the file is 48% smaller with faster checkpoints and opens. Existing stores are unaffected: every agent store has recorded `float16 = false` in /meta and keeps it. A test opens the v2.5.0 fixture, saves and checkpoints, and checks the embeddings are still f32 with the old rows bit-identical; another checks a new store is float16. CLI: `create --f32` opts out; like `--f32-index` it only ever switches the default off. `--float16` is still accepted and now a no-op. Values beyond +-65504 are refused, so f32 remains the choice for unnormalised vectors — the upgrade note says so. Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
2026-09-24 19:39:33 -05:00
parent dbaf3f505d
commit 5c8323cb1e
6 changed files with 109 additions and 25 deletions
@@ -206,3 +206,55 @@ fn wal_replay_rounds_like_a_live_save() {
    assert_eq!(recovered.count(), 30);
    assert_eq!(search_bits(&mut recovered, 77), live);
 }
+
+#[test]
+fn new_stores_default_to_float16() {
+    let dir = TempDir::new().unwrap();
+    let path = dir.path().join("default.h5");
+    let mut m = HDF5Memory::create(MemoryConfig::new(path.clone(), "agent", DIM)).unwrap();
+    assert!(m.config().float16);
+    m.save_batch((0..10).map(entry).collect()).unwrap();
+    drop(m);
+    assert_eq!(embeddings_dtype_and_values(&path).0, "Other(\"float16\")");
+    assert!(HDF5Memory::open(&path).unwrap().config().float16);
+}
+
+#[test]
+fn an_existing_f32_store_stays_f32() {
+    // Written by the v2.5.0 CLI, with `float16 = 0` in /meta (every agent
+    // store has recorded it). Flipping the default for new stores must not
+    // reach back and round an existing store's embeddings.
+    let dir = TempDir::new().unwrap();
+    let path = dir.path().join("legacy.h5");
+    std::fs::copy(
+        concat!(
+            env!("CARGO_MANIFEST_DIR"),
+            "/tests/fixtures/store_v2_5_0.h5"
+        ),
+        &path,
+    )
+    .unwrap();
+    let before = embeddings_dtype_and_values(&path);
+    assert_eq!(before.0, "F32");
+
+    let mut m = HDF5Memory::open(&path).unwrap();
+    assert!(!m.config().float16, "an old store must reopen as f32");
+    let dim = m.config().embedding_dim;
+    let odd: Vec<f32> = (0..dim).map(|i| 0.1 + i as f32 * 1e-4).collect();
+    m.save_batch(vec![MemoryEntry {
+        chunk: "added after the upgrade".into(),
+        embedding: odd.clone(),
+        source_channel: "test".into(),
+        timestamp: 1.0,
+        session_id: "s".into(),
+        tags: String::new(),
+    }])
+    .unwrap();
+    drop(m);
+
+    // Checkpointed: still f32, the old rows untouched and the new one exact.
+    let (dtype, values) = embeddings_dtype_and_values(&path);
+    assert_eq!(dtype, "F32");
+    assert_eq!(&values[..before.1.len()], before.1.as_slice());
+    assert_eq!(&values[before.1.len()..], odd.as_slice());
+}