File size: 1,671 Bytes
0234c79 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 | """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) # true bit-cast flip: lowest mantissa bit
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)
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