Two bugs were blocking memba's main promise (load .memb in a fresh process → model continues with full recalled context): 1. llama_state_set_data() restores the C-level KV-cache + SSM hidden state, but llama-cpp-python's Python wrapper still reports n_tokens=0. The next eval() then decodes new tokens at offset 0 and overwrites the loaded state. Fix: extend MEMB format with an optional 12-byte trailer appended after the CRC32. It carries the wrapper's n_tokens. The C library reads up to CRC and ignores anything past it, so files stay backward-compatible with libmemba; only the Python loader uses it. 2. Llama.__call__ / create_chat_completion / generate all re-tokenise the prompt on every call and clear the KV-cache when the new tokens don't prefix-match input_ids. That destroys any state we just loaded. Fix: rewrite Session.chat() to use raw tokenize → eval → sample. eval() appends tokens to the live state without resetting, and we handle stop-token detection ourselves. Verified end-to-end on Nemotron-3-Nano-4B (hybrid 21x Mamba-2 + 4x attention) — see experiments/README.md for the full findings log. diag_session_nemotron.py, mood_batch_poc.py, mood_stream_poc.py and recall_poc.py now all pass their cross-process tests; Falcon-Mamba still fails because the trained model itself can't do cross-turn recall — that was the original misdiagnosis. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
58 lines
2.9 KiB
Markdown
58 lines
2.9 KiB
Markdown
# experiments/
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Throwaway scripts used to probe SSM/hybrid model capabilities with memba.
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Not part of the library API — kept in the repo as reference and reproducible
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evidence for product decisions.
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Each script is self-contained. Read the source for what it claims to test
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and run it yourself if you want to verify on different models or hardware.
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## Scripts
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| File | What it measures |
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| `recall_poc.py` | git log → state → cross-process "what did I work on last month" |
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| `mood_poc.py` | Batch sentiment trajectory in one prompt — Falcon-Mamba vs Gemma |
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| `mood_batch_poc.py` | Batch ingest, save, query in fresh process |
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| `mood_stream_poc.py` | 15 separate observation turns, save, query in fresh process |
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| `diag_saveload.py` | Minimal hamster recall test on Falcon-Mamba |
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| `diag_nemotron.py` | Same hamster test on Nemotron 4B hybrid |
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| `diag_nemotron2.py` | Cross-process recall via raw `generate()` (bypass `create_chat_completion`) |
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| `diag_nemotron3.py` | Same with llama-cpp-python's native `save_state()`/`load_state()` |
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| `diag_session_nemotron.py` | Full hamster recall through the rewritten `Session.chat()` |
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## Findings log
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### 2026-05-16 (initial, Falcon-Mamba-7B-Instruct Q4_K_M)
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- Batch single-prompt analysis works for both sentiment and recall.
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- Multi-turn fact recall failed even in-process. *Misdiagnosed at first as
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a model capability issue.*
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### 2026-05-16 (revised, after Nemotron-3-Nano-4B Q4_K_M test)
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- Real root cause: `Llama.create_chat_completion()` and `Llama.generate()`
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retokenise the entire prompt each call and reset KV-cache when the new
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tokens don't prefix-match `input_ids`. Loaded memba state was being wiped.
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- Secondary issue: `llama_state_set_data()` restores the C-level cache but
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llama-cpp-python's wrapper still reports `n_tokens=0`, so the next
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`eval()` writes new tokens at offset 0 and overwrites the loaded state.
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- Two fixes in memba:
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1. MEMB file now carries a Python-only trailer with `n_tokens` so the
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wrapper position is restored after `load_state` (12 extra bytes,
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backward-compatible — the C library ignores anything after the CRC).
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2. `Session.chat()` rewritten to use raw `tokenize → eval → sample`
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instead of `Llama.__call__`, avoiding the prefix-matching reset.
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- Results on Nemotron-3-Nano-4B (hybrid: 21 Mamba-2 + 4 attention layers)
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through the new `Session.chat()`:
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- `diag_session_nemotron.py` — cross-process hamster recall: ✅
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- `mood_batch_poc.py` — cross-process mood trajectory: ✅
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- `mood_stream_poc.py` — 15 streaming turns + cross-process: ✅
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- `recall_poc.py` — per-project digest from 30-day git log: ✅ accurate,
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no hallucinated projects.
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Falcon-Mamba was rerun through the new `Session.chat()` but still fails on
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the same tests — the trained model genuinely doesn't have the cross-turn
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recall capability that the hybrid Nemotron does. The 4 attention layers
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make the difference.
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