| """Build the margin-noise PoC twin v2: byte-different, functionally identical copy of the |
| current king. TRUE lowest-mantissa-bit flip on ONE fp16 block scale (bit-cast, not value cast). |
| """ |
| import hashlib |
| import shutil |
| import sys |
| from pathlib import Path |
|
|
| sys.path.insert(0, "/root/ingot/src") |
| import numpy as np |
|
|
| from common.gguf import read_header |
| from common.gguf.types import PQ2_0 |
|
|
| KING = Path("/root/models/king-xii/Ingot-XII-27B-Q2.gguf") |
| OUT_DIR = Path("/root/models/chal-twin") |
| OUT = OUT_DIR / KING.name |
|
|
| g = read_header(KING) |
| pq = sorted(n for n, t in g.tensors.items() if t.ggml_type == PQ2_0 and n.startswith("blk.30.")) |
| name = pq[0] |
| t = g.tensors[name] |
| n_blocks = int(np.prod(t.shape)) // 128 |
| print(f"twin base tensor: {name} ({n_blocks} blocks)") |
|
|
| OUT_DIR.mkdir(parents=True, exist_ok=True) |
| shutil.copy(KING, OUT) |
| raw = np.memmap(OUT, np.uint8, "r+", g.data_start + t.offset, (n_blocks * 34,)) |
| b = raw.reshape(-1, 34) |
| old_bytes = b[0, :2].copy() |
| old_bits = old_bytes.view("<u2")[0] |
| new_bits = np.uint16(old_bits ^ 0x0001) |
| b[0, :2] = np.asarray([new_bits], "<u2").view(np.uint8) |
| raw.flush() |
|
|
| old_val = np.asarray([old_bits], "<u2").view("<f2")[0] |
| new_val = np.asarray([new_bits], "<u2").view("<f2")[0] |
|
|
|
|
| def h(p): |
| m = hashlib.sha256() |
| with open(p, "rb") as f: |
| for c in iter(lambda: f.read(1 << 24), b""): |
| m.update(c) |
| return m.hexdigest()[:16] |
|
|
|
|
| print(f"scale block0: {old_val:.8e} -> {new_val:.8e} (rel change {abs(new_val-old_val)/abs(old_val):.2e})") |
| print(f"king sha256 {h(KING)}") |
| print(f"twin sha256 {h(OUT)}") |
| print("byte-different:", h(KING) != h(OUT)) |
| print("WROTE", OUT) |
|
|
