Files
emilandClaude Opus 4.7 ee8a9fc5bc Fix cross-process recall: MEMB trailer + raw eval/sample in chat()
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>
2026-05-16 13:18:31 +03:00

92 lines
3.4 KiB
Python

"""
diag_nemotron3.py — test hypothesis that llama-cpp-python's built-in
save_state/load_state preserves Python-side trackers (n_tokens, input_ids)
which memba's raw C-level save/load is missing.
If built-in works → memba's MEMB format needs to be extended to include
those trackers. If built-in also fails → the issue is elsewhere.
"""
import sys, time, pickle
from pathlib import Path
sys.path.insert(0, str(Path(__file__).resolve().parent.parent / "python"))
from llama_cpp import Llama
MODEL = "/home/emil/Desktop/Coding/AI/Memba/NVIDIA-Nemotron3-Nano-4B-Q4_K_M.gguf"
STATE = "/tmp/diag_nemotron_native.pickle"
INGEST = ("I'm going to tell you a fact about my pet. My pet hamster is named "
"Bartholomew. He is 4 years old. Reply with just 'noted'.")
QUERY = "What is the name of my pet?"
def make_llama():
return Llama(model_path=MODEL, n_ctx=4096, n_gpu_layers=-1, verbose=False)
def build():
m = make_llama()
print(f"[build] initial n_tokens={m.n_tokens}")
msgs = [{"role": "user", "content": INGEST}]
out = m.create_chat_completion(messages=msgs, max_tokens=80, temperature=0.1)
ack = out["choices"][0]["message"]["content"]
msgs.append({"role": "assistant", "content": ack})
print(f"[build] after ingest: n_tokens={m.n_tokens}")
print(f"[build] ack snippet: {ack[-100:]!r}")
# Use llama-cpp-python's NATIVE save_state — captures Python trackers too
state = m.save_state()
with open(STATE, "wb") as f:
pickle.dump(state, f)
print(f"[build] saved native state to {STATE} ({Path(STATE).stat().st_size:,} B)")
def query():
if not Path(STATE).exists():
print("[query] no state file"); return
m = make_llama()
print(f"[query] before load: n_tokens={m.n_tokens}")
with open(STATE, "rb") as f:
state = pickle.load(f)
m.load_state(state)
print(f"[query] after load: n_tokens={m.n_tokens}")
# Now ask via create_chat_completion. Pass ONLY the new question
# (history is already in KV-cache+n_tokens).
# The template will format this as if it's turn 1 — see what happens.
out = m.create_chat_completion(
messages=[{"role": "user", "content": QUERY}],
max_tokens=150, temperature=0.1,
)
print(f"\n[query] answer via chat_completion (resets context):\n{out['choices'][0]['message']['content']}")
# Alternative: try to continue manually, using raw eval
print(f"\n[query] re-loading state for raw continuation test")
with open(STATE, "rb") as f:
state = pickle.load(f)
m.load_state(state)
print(f"[query] re-loaded: n_tokens={m.n_tokens}")
# Append a new user turn via raw tokens, then generate
continuation = "<|im_end|>\n<|im_start|>user\nWhat is the name of my pet?<|im_end|>\n<|im_start|>assistant\n"
tokens = m.tokenize(continuation.encode(), add_bos=False, special=True)
out_tokens = []
eos = m.token_eos()
for tok in m.generate(tokens, top_k=1, temp=0.0):
if tok == eos or len(out_tokens) >= 150:
break
out_tokens.append(tok)
snippet = m.detokenize(out_tokens).decode("utf-8", errors="ignore")
if "<|im_end|>" in snippet:
break
text = m.detokenize(out_tokens).decode("utf-8", errors="ignore")
print(f"\n[query] raw continuation answer:\n{text}")
if __name__ == "__main__":
cmd = sys.argv[1] if len(sys.argv) > 1 else "build"
{"build": build, "query": query}[cmd]()