Files
rzen c202bada6a Phase 2: token dataset + corpus encoder (code only, not yet run)
- src/dataset.py: memmap uint16 token loader + random-crop batch sampler
  (x, y shifted-by-one, reproducible via generator)
- scripts/encode_corpus.py: stream stories -> encode -> uint16 .bin, one EOT
  token appended per story, flat memory. encode_file() factored out for testing.
- tests/test_dataset.py: batch shapes/shift/bounds/reproducibility +
  encoder round-trip/separators/uint16 on synthetic data (5 tests)
2026-07-12 10:38:20 -04:00

97 lines
3.2 KiB
Python

"""Encode the raw corpus into flat uint16 token files.
Each story in the source is delimited by a line containing only
``<|endoftext|>``. We stream the file one line at a time, encode each story
with the trained tokenizer, append the end-of-text token id after it, and flush
the ids to disk in batches — so memory stays flat regardless of corpus size.
Output: data/tokens/train.bin and data/tokens/val.bin.
Usage:
python scripts/encode_corpus.py
"""
import sys
import time
from pathlib import Path
import numpy as np
ROOT = Path(__file__).resolve().parent.parent
sys.path.insert(0, str(ROOT / "src"))
from dataset import TOKEN_DTYPE # noqa: E402
from tokenizer import BPETokenizer # noqa: E402
EOT = "<|endoftext|>"
TOK_PATH = ROOT / "artifacts" / "tokenizer.json"
RAW = ROOT / "data" / "raw"
OUT = ROOT / "data" / "tokens"
FLUSH_EVERY = 20_000 # stories between disk writes / progress updates
JOBS = [
("TinyStoriesV2-GPT4-train.txt", "train.bin"),
("TinyStoriesV2-GPT4-valid.txt", "val.bin"),
]
def encode_file(tok: BPETokenizer, src: Path, dst: Path, progress: bool = True) -> tuple[int, int]:
"""Encode one corpus file to a uint16 .bin. Returns (n_stories, n_tokens)."""
eot_id = tok.special_tokens[EOT]
buf: list[int] = []
story: list[str] = []
n_stories = n_tokens = 0
t0 = time.perf_counter()
def emit(text: str) -> None:
nonlocal n_stories, n_tokens
text = text.strip()
if not text:
return # skip blank runs between separators
ids = tok.encode(text)
ids.append(eot_id)
buf.extend(ids)
n_stories += 1
n_tokens += len(ids)
with open(src, "r", encoding="utf-8", errors="ignore") as fin, open(dst, "wb") as fout:
for line in fin:
if line.strip() == EOT:
emit("".join(story))
story = []
if n_stories % FLUSH_EVERY == 0 and buf:
np.asarray(buf, dtype=TOKEN_DTYPE).tofile(fout)
buf.clear()
if progress:
rate = n_stories / (time.perf_counter() - t0)
print(f"\r {dst.name}: {n_stories:,} stories, "
f"{n_tokens:,} tokens ({rate:,.0f}/s)", end="", flush=True)
else:
story.append(line)
emit("".join(story)) # trailing story with no final separator
if buf:
np.asarray(buf, dtype=TOKEN_DTYPE).tofile(fout)
if progress:
print()
return n_stories, n_tokens
def main() -> None:
if not TOK_PATH.exists():
sys.exit(f"missing {TOK_PATH} — run scripts/train_tokenizer.py first")
tok = BPETokenizer.load(TOK_PATH)
OUT.mkdir(parents=True, exist_ok=True)
for src_name, dst_name in JOBS:
src, dst = RAW / src_name, OUT / dst_name
if not src.exists():
sys.exit(f"missing {src} — run scripts/download_data.py first")
print(f"encoding {src_name} -> {dst_name}")
n_stories, n_tokens = encode_file(tok, src, dst)
size_mb = dst.stat().st_size / 1e6
print(f" done: {n_stories:,} stories, {n_tokens:,} tokens, {size_mb:,.0f} MB")
if __name__ == "__main__":
main()