dela
e7185cbf49
train_sft --data opus-100 streams Helsinki-NLP/opus-100, writes both directions, and skips frozen eval sentences. Runtime cache stays under data/sft/ (gitignored).
467 lines
14 KiB
Python
467 lines
14 KiB
Python
"""Pretrain / SFT sample construction.
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Pretrain: Wikipedia parquet → tokenize → pack (B, T). Languages mix 1:1 by
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token via seq_len-sized blocks so each training chunk is monolingual.
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SFT: instruction-parallel rows → prompt-masked labels. Template lives in
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``prompts.instruction_prompt`` (same string as eval_mt).
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"""
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from __future__ import annotations
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import json
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import os
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from dataclasses import dataclass
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from pathlib import Path
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from typing import Iterable, Protocol
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import torch
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from .prompts import instruction_prompt
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WIKI_SHARD_TOTAL = {"zh": 6, "en": 41}
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WIKI_PATH = "datasets/wikimedia/wikipedia/resolve/main/20231101.{lang}"
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IGNORE_INDEX = -100
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def _hf_endpoint() -> str:
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"""Hub origin. OpenBayes/CN: export HF_ENDPOINT=https://hf-mirror.com"""
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return os.environ.get("HF_ENDPOINT", "https://huggingface.co").rstrip("/")
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class Tokenizer(Protocol):
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vocab_size: int
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def encode(self, text: str) -> list[int]: ...
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def decode(self, ids: list[int]) -> str: ...
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@dataclass
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class SentencePieceTokenizer:
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_sp: object
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@property
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def vocab_size(self) -> int:
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return int(self._sp.vocab_size())
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def encode(self, text: str) -> list[int]:
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return list(self._sp.encode(text, out_type=int))
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def decode(self, ids: list[int]) -> str:
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return str(self._sp.decode(ids))
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@dataclass
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class HuggingFaceTokenizer:
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_tok: object
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@property
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def vocab_size(self) -> int:
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return int(len(self._tok))
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def encode(self, text: str) -> list[int]:
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return list(self._tok.encode(text, add_special_tokens=False))
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def decode(self, ids: list[int]) -> str:
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return str(self._tok.decode(ids, skip_special_tokens=True))
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def load_tokenizer(source: str) -> Tokenizer:
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"""`.model` 走 SentencePiece, 其它当作 HuggingFace 名或本地目录."""
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if source.endswith(".model"):
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from sentencepiece import SentencePieceProcessor
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return SentencePieceTokenizer(SentencePieceProcessor(model_file=source))
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from transformers import AutoTokenizer
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tok = AutoTokenizer.from_pretrained(source, trust_remote_code=True)
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return HuggingFaceTokenizer(tok)
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def pretrain_dir() -> Path:
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for candidate in (
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os.environ.get("KDA_PRETRAIN_DIR"),
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"/data/pretrain",
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"data/pretrain",
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):
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if candidate and Path(candidate).is_dir():
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return Path(candidate)
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return Path("data/pretrain")
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def sft_dir() -> Path:
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for candidate in (
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os.environ.get("KDA_SFT_DIR"),
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"/data/sft",
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"data/sft",
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):
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if candidate and Path(candidate).is_dir():
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return Path(candidate)
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return Path("data/sft")
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def _wiki_files(lang: str, n_shards: int) -> list[str]:
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if lang not in WIKI_SHARD_TOTAL:
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raise ValueError(f"unsupported wiki lang {lang!r}; expected zh or en")
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total = WIKI_SHARD_TOTAL[lang]
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n = min(max(n_shards, 1), total)
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base = f"{_hf_endpoint()}/{WIKI_PATH.format(lang=lang)}"
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return [f"{base}/train-{i:05d}-of-{total:05d}.parquet" for i in range(n)]
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def _cache_path(cache_dir: Path, lang: str, n_shards: int, limit: int) -> Path:
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return cache_dir / f"wiki-{lang}-n{n_shards}-limit{limit}.jsonl"
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def fetch_wiki_texts(
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limit: int,
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lang: str = "zh",
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n_shards: int = 2,
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cache_dir: str | Path | None = None,
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) -> list[str]:
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"""Load up to ``limit`` article bodies, caching jsonl under pretrain_dir."""
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cache = Path(cache_dir) if cache_dir is not None else pretrain_dir()
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cache.mkdir(parents=True, exist_ok=True)
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path = _cache_path(cache, lang, n_shards, limit)
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if path.exists():
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texts: list[str] = []
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with path.open(encoding="utf-8") as fh:
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for line in fh:
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line = line.strip()
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if not line:
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continue
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texts.append(json.loads(line)["text"])
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if len(texts) >= limit:
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break
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if texts:
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return texts
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from datasets import load_dataset
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files = _wiki_files(lang, n_shards)
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ds = load_dataset("parquet", data_files=files, split="train", streaming=True)
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texts = []
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for i, row in enumerate(ds):
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if i >= limit:
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break
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texts.append(row["text"])
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tmp = path.with_suffix(path.suffix + ".tmp")
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with tmp.open("w", encoding="utf-8") as fh:
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for text in texts:
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fh.write(json.dumps({"text": text}, ensure_ascii=False) + "\n")
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tmp.replace(path)
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return texts
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def tokenize_corpus(texts: list[str], tok: Tokenizer) -> list[int]:
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ids: list[int] = []
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for text in texts:
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ids.extend(tok.encode(text))
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return ids
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def interleave_balanced(ids_a: list[int], ids_b: list[int], block: int) -> list[int]:
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"""1:1 by token: seq_len-sized monolingual blocks, drop the longer tail."""
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if block < 1:
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raise ValueError(f"block must be >= 1, got {block}")
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n = min(len(ids_a), len(ids_b))
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n = (n // block) * block
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out: list[int] = []
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a, b = ids_a, ids_b
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for i in range(0, n, block):
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out.extend(a[i : i + block])
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out.extend(b[i : i + block])
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return out
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def chunk_ids(ids: list[int], batch: int, seq_len: int) -> torch.Tensor:
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"""切成 (num_chunks, B, T); 末尾不足部分丢弃."""
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n = (len(ids) // (batch * seq_len)) * (batch * seq_len)
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t = torch.tensor(ids[:n], dtype=torch.long)
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if n == 0:
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return t.view(0, batch, seq_len)
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return t.view(batch, -1, seq_len).transpose(0, 1)
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def split_heldout(
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chunks: torch.Tensor,
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frac: float = 0.01,
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min_heldout: int = 1,
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) -> tuple[torch.Tensor, torch.Tensor]:
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"""Last ``frac`` of packed chunks for CE only. Empty held-out if too few."""
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n = int(chunks.size(0))
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if n <= 1 or frac <= 0:
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return chunks, chunks[:0]
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h = max(min_heldout, int(n * frac))
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h = min(h, n - 1)
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return chunks[:-h], chunks[-h:]
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def iter_chunks(chunks: torch.Tensor):
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"""逐块产出 (input_ids, labels), labels 右移 (模型内 CE shift)."""
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for chunk in chunks:
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yield chunk, chunk.clone()
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def iter_indexed(chunks: torch.Tensor, start: int = 0):
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"""Infinite cycle with a global index (for --resume)."""
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n = int(chunks.size(0))
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if n == 0:
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raise ValueError("no training chunks")
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i = start
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while True:
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x = chunks[i % n]
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yield i, x, x.clone()
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i += 1
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def load_pretrain_chunks(
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tok: Tokenizer,
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*,
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langs: Iterable[str],
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limit: int,
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batch: int,
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seq_len: int,
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heldout_frac: float = 0.01,
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n_shards: int = 2,
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cache_dir: str | Path | None = None,
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) -> tuple[torch.Tensor, torch.Tensor, int]:
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"""Fetch / cache / tokenize / pack. Returns train chunks, held-out, token count."""
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lang_list = [lang.strip() for lang in langs if lang.strip()]
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if not lang_list:
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raise ValueError("langs must contain at least one of zh, en")
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streams: list[list[int]] = []
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for lang in lang_list:
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print(f"loading {limit} wiki articles ({lang}) ...")
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texts = fetch_wiki_texts(limit, lang=lang, n_shards=n_shards, cache_dir=cache_dir)
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streams.append(tokenize_corpus(texts, tok))
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print(f" {lang}: {len(streams[-1]):,} tokens from {len(texts)} articles")
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if len(streams) == 1:
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ids = streams[0]
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else:
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ids = streams[0]
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for extra in streams[1:]:
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ids = interleave_balanced(ids, extra, seq_len)
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chunks = chunk_ids(ids, batch, seq_len)
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train, held = split_heldout(chunks, heldout_frac)
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return train, held, len(ids)
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def pad_id(tok: Tokenizer) -> int:
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inner = getattr(tok, "_tok", None)
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if inner is not None:
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pid = getattr(inner, "pad_token_id", None)
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if pid is not None:
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return int(pid)
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eid = getattr(inner, "eos_token_id", None)
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if eid is not None:
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return int(eid)
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return 0
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def eos_id(tok: Tokenizer) -> int | None:
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inner = getattr(tok, "_tok", None)
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if inner is not None:
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eid = getattr(inner, "eos_token_id", None)
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if eid is not None:
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return int(eid)
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convert = getattr(inner, "convert_tokens_to_ids", None)
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if convert is not None:
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tid = convert("<|im_end|>")
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if isinstance(tid, int) and tid >= 0:
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return tid
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return None
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def encode_sft_row(
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tok: Tokenizer,
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src: str,
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tgt: str,
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target_lang: str,
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max_len: int,
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eos: int | None = None,
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) -> tuple[list[int], list[int]]:
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prompt_ids = tok.encode(instruction_prompt(src, target_lang))
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tgt_ids = tok.encode(tgt)
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if eos is not None:
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tgt_ids = tgt_ids + [eos]
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ids = prompt_ids + tgt_ids
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labels = [IGNORE_INDEX] * len(prompt_ids) + list(tgt_ids)
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if len(ids) > max_len:
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overflow = len(ids) - max_len
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cut = min(overflow, max(len(prompt_ids) - 1, 0))
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ids = ids[cut:]
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labels = labels[cut:]
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if len(ids) > max_len:
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ids = ids[:max_len]
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labels = labels[:max_len]
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return ids, labels
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def _eval_blocklist(eval_dir: str | Path | None = None) -> set[str]:
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"""Frozen eval sentences must not appear in SFT bitext."""
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blocked: set[str] = set()
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folders = []
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if eval_dir is not None:
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folders.append(Path(eval_dir))
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folders.extend(
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[
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Path(os.environ["KDA_EVAL_DIR"]) if os.environ.get("KDA_EVAL_DIR") else None,
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Path("/data/eval"),
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Path("data/eval"),
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]
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)
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for folder in folders:
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if folder is None or not folder.is_dir():
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continue
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for path in folder.glob("*.txt"):
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for line in path.read_text(encoding="utf-8").splitlines():
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text = line.strip()
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if text:
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blocked.add(text)
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return blocked
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def fetch_opus100_enzh(
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limit: int,
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*,
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both_dirs: bool = True,
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cache_dir: str | Path | None = None,
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eval_dir: str | Path | None = None,
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) -> list[dict]:
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"""Stream Helsinki-NLP/opus-100 ``en-zh`` train. ``limit`` is source pairs."""
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if limit < 1:
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raise ValueError(f"limit must be >= 1, got {limit}")
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cache = Path(cache_dir) if cache_dir is not None else sft_dir()
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cache.mkdir(parents=True, exist_ok=True)
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tag = "both" if both_dirs else "enzh"
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path = cache / f"opus100-en-zh-{tag}-limit{limit}.jsonl"
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if path.exists():
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rows = load_sft_rows(path)
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if rows:
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return rows
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from datasets import load_dataset
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ds = load_dataset("Helsinki-NLP/opus-100", "en-zh", split="train", streaming=True)
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blocked = _eval_blocklist(eval_dir)
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rows: list[dict] = []
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n_src = 0
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for row in ds:
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trans = row.get("translation") if isinstance(row, dict) else None
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blob = trans if isinstance(trans, dict) else row
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en = str(blob.get("en") or "").strip()
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zh = str(blob.get("zh") or "").strip()
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if not en or not zh or en == zh:
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continue
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if en in blocked or zh in blocked:
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continue
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if min(len(en), len(zh)) < 2:
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continue
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n_src += 1
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rows.append({"src": zh, "tgt": en, "target_lang": "en"})
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if both_dirs:
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rows.append({"src": en, "tgt": zh, "target_lang": "zh"})
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if n_src >= limit:
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break
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tmp = path.with_suffix(path.suffix + ".tmp")
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with tmp.open("w", encoding="utf-8") as fh:
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for row in rows:
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fh.write(json.dumps(row, ensure_ascii=False) + "\n")
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tmp.replace(path)
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return rows
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def resolve_sft_rows(
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source: str,
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*,
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limit: int = 100_000,
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both_dirs: bool = True,
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cache_dir: str | Path | None = None,
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eval_dir: str | Path | None = None,
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) -> list[dict]:
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"""Local jsonl/tsv, or ``opus-100`` / ``opus`` to pull OPUS-100 en-zh from HF."""
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path = Path(source)
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if path.is_file():
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return load_sft_rows(path)
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key = source.strip().lower().replace("_", "-")
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if key in {"opus", "opus-100", "opus100", "helsinki-nlp/opus-100"}:
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print(f"fetching OPUS-100 en-zh (limit {limit} pairs, both_dirs={both_dirs})")
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return fetch_opus100_enzh(
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limit, both_dirs=both_dirs, cache_dir=cache_dir, eval_dir=eval_dir
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)
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raise FileNotFoundError(
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f"SFT source {source!r} is not a file; use a jsonl path or 'opus-100'"
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)
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def load_sft_rows(path: str | Path) -> list[dict]:
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"""jsonl ``{src,tgt,target_lang}`` or TSV ``src\\ttgt\\ttarget_lang``."""
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p = Path(path)
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rows: list[dict] = []
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text = p.read_text(encoding="utf-8")
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if p.suffix == ".jsonl" or p.suffix == ".json":
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for line in text.splitlines():
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line = line.strip()
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if not line:
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continue
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obj = json.loads(line)
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rows.append(
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{
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"src": obj["src"],
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"tgt": obj["tgt"],
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"target_lang": obj.get("target_lang", "en"),
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}
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)
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return rows
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for line in text.splitlines():
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line = line.strip()
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if not line or line.startswith("#"):
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continue
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parts = line.split("\t")
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if len(parts) < 2:
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raise ValueError(f"SFT TSV needs src, tgt [, target_lang]: {line[:80]!r}")
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lang = parts[2] if len(parts) > 2 else "en"
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rows.append({"src": parts[0], "tgt": parts[1], "target_lang": lang})
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return rows
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def collate_sft(
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rows: list[dict],
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tok: Tokenizer,
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max_len: int,
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) -> tuple[torch.Tensor, torch.Tensor]:
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pad = pad_id(tok)
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eos = eos_id(tok)
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encoded = [
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encode_sft_row(tok, r["src"], r["tgt"], r["target_lang"], max_len, eos)
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for r in rows
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]
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width = min(max(len(ids) for ids, _ in encoded), max_len)
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width = max(width, 2)
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bsz = len(encoded)
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input_ids = torch.full((bsz, width), pad, dtype=torch.long)
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labels = torch.full((bsz, width), IGNORE_INDEX, dtype=torch.long)
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for i, (ids, lab) in enumerate(encoded):
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n = min(len(ids), width)
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input_ids[i, :n] = torch.tensor(ids[:n], dtype=torch.long)
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labels[i, :n] = torch.tensor(lab[:n], dtype=torch.long)
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return input_ids, labels
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def iter_sft_batches(
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rows: list[dict],
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tok: Tokenizer,
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batch: int,
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max_len: int,
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start: int = 0,
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):
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n = len(rows)
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if n == 0:
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raise ValueError("no SFT rows")
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i = start
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while True:
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sl = [rows[j % n] for j in range(i, i + batch)]
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yield i, *collate_sft(sl, tok, max_len)
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i += batch
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