mlx-examples/llms/mlx_lm/tuner/datasets.py
Chime Ogbuji 5865899c81
Completion only fine-tuning of instruction models with collections of HF datasets (#1103)
- Optional completion only fine-tuning with `--mask-prompt`
- Collections of Hugging Face datasets

---------

Co-authored-by: Awni Hannun <awni@apple.com>
2025-02-09 20:12:34 -08:00

274 lines
7.9 KiB
Python

import itertools
import json
import types
from pathlib import Path
from typing import Any, Dict, List, Optional
from transformers import PreTrainedTokenizer
class Dataset:
"""
Light-weight wrapper to hold a dataset.
"""
def __init__(
self,
data: List[Dict[str, str]],
tokenizer: PreTrainedTokenizer,
text_key: str = "text",
):
self._data = [tokenizer.encode(d[text_key]) for d in data]
for d in self._data:
if d[-1] != tokenizer.eos_token_id:
d.append(tokenizer.eos_token_id)
def __getitem__(self, idx: int):
return self._data[idx]
def __len__(self):
return len(self._data)
class ChatDataset:
"""
A dataset for chat data in the format of {"messages": [...]}
https://platform.openai.com/docs/guides/fine-tuning/example-format
"""
def __init__(
self,
data: List[Dict[str, str]],
tokenizer: PreTrainedTokenizer,
chat_key: str = "messages",
mask_prompt: bool = False,
):
self._data = []
for d in data:
messages = d[chat_key]
tools = d.get("tools", None)
tokens = tokenizer.apply_chat_template(messages, tools=tools)
if mask_prompt:
messages = messages[:-1]
offset = len(tokenizer.apply_chat_template(messages, tools=tools))
self._data.append((tokens, offset))
else:
self._data.append(tokens)
def __getitem__(self, idx: int):
return self._data[idx]
def __len__(self):
return len(self._data)
class CompletionsDataset:
"""
A dataset for prompt-completion data in the format of {"prompt": ..., "completion": ...}
or using user-provided keys for prompt and completion values
https://platform.openai.com/docs/guides/fine-tuning/example-format
"""
def __init__(
self,
data: List[Dict[str, str]],
tokenizer: PreTrainedTokenizer,
prompt_key: str,
completion_key: str,
mask_prompt: bool,
):
self._data = []
for d in data:
tokens = tokenizer.apply_chat_template(
[
{"role": "user", "content": d[prompt_key]},
{"role": "assistant", "content": d[completion_key]},
],
)
if mask_prompt:
offset = len(
tokenizer.apply_chat_template(
[{"role": "user", "content": d[prompt_key]}]
)
)
self._data.append((tokens, offset))
else:
self._data.append(tokens)
def __getitem__(self, idx: int):
return self._data[idx]
def __len__(self):
return len(self._data)
class ConcatenatedDataset:
def __init__(self, data: List[Any]):
self._data = list(itertools.chain(*data))
def __getitem__(self, idx: int):
return self._data[idx]
def __len__(self):
return len(self._data)
def create_dataset(
data,
tokenizer: PreTrainedTokenizer,
config,
):
mask_prompt = getattr(config, "mask_prompt", False)
prompt_feature = getattr(config, "prompt_feature", "prompt")
text_feature = getattr(config, "text_feature", "text")
completion_feature = getattr(config, "completion_feature", "completion")
chat_feature = getattr(config, "chat_feature", "messages")
sample = data[0]
if prompt_feature in sample and completion_feature in sample:
return CompletionsDataset(
data, tokenizer, prompt_feature, completion_feature, mask_prompt
)
elif chat_feature in sample:
return ChatDataset(
data, tokenizer, chat_key=chat_feature, mask_prompt=mask_prompt
)
elif text_feature in sample:
if mask_prompt:
raise ValueError("Prompt masking not supported for text dataset.")
return Dataset(data, tokenizer, text_key=text_feature)
else:
raise ValueError(
"Unsupported data format, check the supported formats here:\n"
"https://github.com/ml-explore/mlx-examples/blob/main/llms/mlx_lm/LORA.md#data."
)
def load_local_dataset(
data_path: Path,
tokenizer: PreTrainedTokenizer,
config,
):
def load_subset(path):
if not path.exists():
return []
with open(path, "r") as fid:
data = [json.loads(l) for l in fid]
return create_dataset(data, tokenizer, config)
names = ("train", "valid", "test")
train, valid, test = [load_subset(data_path / f"{n}.jsonl") for n in names]
return train, valid, test
def load_hf_dataset(
data_id: str,
tokenizer: PreTrainedTokenizer,
config,
):
from datasets import exceptions, load_dataset
try:
dataset = load_dataset(data_id)
names = ("train", "valid", "test")
train, valid, test = [
(
create_dataset(dataset[n], tokenizer, config)
if n in dataset.keys()
else []
)
for n in names
]
except exceptions.DatasetNotFoundError:
raise ValueError(f"Not found Hugging Face dataset: {data_id} .")
return train, valid, test
def load_custom_hf_dataset(args, tokenizer: PreTrainedTokenizer):
import datasets
def create_hf_dataset(dataset_name, config, split, hf_config):
ds = datasets.load_dataset(
dataset_name,
split=split,
**hf_config,
)
return create_dataset(ds, tokenizer, config)
dataset_collection = args.hf_dataset
if isinstance(dataset_collection, dict):
dataset_collection = [dataset_collection]
collection = []
for ds in dataset_collection:
ds_name = ds["name"]
print(f"Loading Hugging Face dataset {ds_name}.")
ds["mask_prompt"] = getattr(args, "mask_prompt", False)
config = types.SimpleNamespace(**ds)
hf_config = ds.get("config", {})
if args.train:
train_split = ds.get("train_split", "train[:80%]")
valid_split = ds.get("valid_split", "train[-10%:]")
train = create_hf_dataset(
ds_name,
config,
train_split,
hf_config,
)
valid = create_hf_dataset(
ds_name,
config,
valid_split,
hf_config,
)
else:
train, valid = [], []
if args.test:
test_split = ds.get("test_split")
test = create_hf_dataset(
ds_name,
config,
test_split,
hf_config,
)
else:
test = []
collection.append((train, valid, test))
if len(collection) == 1:
return collection[0]
# Otherwise concatenate them
return tuple(map(ConcatenatedDataset, zip(*collection)))
def load_dataset(args, tokenizer: PreTrainedTokenizer):
if getattr(args, "hf_dataset", False):
train, valid, test = load_custom_hf_dataset(args, tokenizer)
else:
data_path = Path(args.data)
if data_path.exists():
train, valid, test = load_local_dataset(data_path, tokenizer, args)
else:
print(f"Loading Hugging Face dataset {args.data}.")
train, valid, test = load_hf_dataset(args.data, tokenizer, args)
if args.train and len(train) == 0:
raise ValueError(
"Training set not found or empty. Must provide training set for fine-tuning."
)
if args.train and len(valid) == 0:
raise ValueError(
"Validation set not found or empty. Must provide validation set for fine-tuning."
)
if args.test and len(test) == 0:
raise ValueError(
"Test set not found or empty. Must provide test set for evaluation."
)
return train, valid, test