ORPO Trainer replacement (#1551)

* WIP use trl ORPOTrainer

* fixes to make orpo work with trl

* fix the chat template laoding

* make sure to handle the special tokens and add_generation for assistant turn too

requirements.txt

@@ -39,6 +39,6 @@ s3fs
 gcsfs
 # adlfs
 
-trl @ git+https://github.com/huggingface/trl.git@0ee349dcd43b0f4b3169449f16751c38ac4a609f
+trl==0.8.5
 zstandard==0.22.0
 fastcore

src/axolotl/cli/preprocess.py

@@ -54,7 +54,7 @@ def do_cli(config: Union[Path, str] = Path("examples/"), **kwargs):
         LOG.warning(msg)
         parsed_cfg.dataset_prepared_path = DEFAULT_DATASET_PREPARED_PATH
 
-    if parsed_cfg.rl and parsed_cfg.rl != "orpo":
+    if parsed_cfg.rl:  # and parsed_cfg.rl != "orpo":
         load_rl_datasets(cfg=parsed_cfg, cli_args=parsed_cli_args)
     else:
         load_datasets(cfg=parsed_cfg, cli_args=parsed_cli_args)

src/axolotl/cli/train.py

@@ -47,7 +47,7 @@ def do_train(cfg, cli_args) -> Tuple[PreTrainedModel, PreTrainedTokenizer]:
     else:
         register_chatml_template()
 
-    if cfg.rl and cfg.rl != "orpo":
+    if cfg.rl:  # and cfg.rl != "orpo":
         dataset_meta = load_rl_datasets(cfg=cfg, cli_args=cli_args)
     else:
         dataset_meta = load_datasets(cfg=cfg, cli_args=cli_args)

src/axolotl/core/trainer_builder.py

@@ -30,7 +30,7 @@ from transformers import (
 )
 from transformers.trainer_utils import seed_worker
 from transformers.utils import is_sagemaker_mp_enabled
-from trl import DPOTrainer
+from trl import DPOTrainer, ORPOConfig, ORPOTrainer
 from trl.trainer.utils import pad_to_length
 
 from axolotl.loraplus import create_loraplus_optimizer
@@ -810,6 +810,14 @@ class AxolotlDPOTrainer(DPOTrainer):
         return res
 
 
+class AxolotlORPOTrainer(ORPOTrainer):
+    """
+    Extend the base ORPOTrainer for axolotl helpers
+    """
+
+    tag_names = ["axolotl", "orpo"]
+
+
 class TrainerBuilderBase(abc.ABC):
     """
     Base class for trainer builder
@@ -1404,7 +1412,7 @@ class HFCausalTrainerBuilder(TrainerBuilderBase):
         )
 
 
-class HFDPOTrainerBuilder(TrainerBuilderBase):
+class HFRLTrainerBuilder(TrainerBuilderBase):
     """
     Trainer factory class for DPO Trainer
     """
@@ -1497,7 +1505,15 @@ class HFDPOTrainerBuilder(TrainerBuilderBase):
             # default to saving each epoch if not defined
             training_args_kwargs["save_strategy"] = "epoch"
 
-        training_args = TrainingArguments(
+        if self.cfg.orpo_alpha:
+            # trl does some odd mapping of alpha to beta to reuse the beta parameter ???
+            training_args_kwargs["beta"] = self.cfg.orpo_alpha
+
+        training_args_cls = TrainingArguments
+        if self.cfg.rl == "orpo":
+            training_args_cls = ORPOConfig
+
+        training_args = training_args_cls(
             per_device_train_batch_size=self.cfg.micro_batch_size,
             max_steps=self.cfg.max_steps or total_num_steps,
             gradient_accumulation_steps=self.cfg.gradient_accumulation_steps,
@@ -1530,17 +1546,26 @@ class HFDPOTrainerBuilder(TrainerBuilderBase):
             dpo_trainer_kwargs[
                 "precompute_ref_log_probs"
             ] = self.cfg.precompute_ref_log_probs
-        dpo_trainer = AxolotlDPOTrainer(
-            self.model,
-            self.model_ref,
+        if self.cfg.rl in ["dpo", "ipo", "kto_pair"]:
+            trainer_cls = AxolotlDPOTrainer
+            dpo_trainer_kwargs["beta"] = self.cfg.dpo_beta or 0.1
+            trainer_cls_args = [self.model, self.model_ref]
+
+            # these aren't used for the ORPO trainer
+            dpo_trainer_kwargs["max_length"] = self.cfg.sequence_len
+            dpo_trainer_kwargs["max_target_length"] = None
+            dpo_trainer_kwargs["max_prompt_length"] = self.cfg.sequence_len
+            dpo_trainer_kwargs["generate_during_eval"] = True
+        elif self.cfg.rl == "orpo":
+            trainer_cls = AxolotlORPOTrainer
+            trainer_cls_args = [self.model]
+        else:
+            raise ValueError(f"Unsupported RL: {self.cfg.rl}")
+        dpo_trainer = trainer_cls(
+            *trainer_cls_args,
             args=training_args,
-            beta=self.cfg.dpo_beta or 0.1,
             train_dataset=self.train_dataset,
             tokenizer=self.tokenizer,
-            max_length=self.cfg.sequence_len,
-            max_target_length=None,
-            max_prompt_length=self.cfg.sequence_len,
-            generate_during_eval=True,
             callbacks=self.get_callbacks(),
             **dpo_trainer_kwargs,
         )

src/axolotl/prompt_strategies/orpo/__init__.py

@@ -6,4 +6,4 @@ from functools import partial
 
 from ..base import load as load_base
 
-load = partial(load_base, module="axolotl.prompt_strategies.orpo")
+load = partial(load_base, module_base="axolotl.prompt_strategies.orpo")

src/axolotl/prompt_strategies/orpo/chat_template.py

@@ -78,6 +78,57 @@ class ORPODatasetParsingStrategy:
         )
         return MessageList(messages=messages)
 
+    def get_prompt(self, prompt) -> MessageList:
+        """Map the data to extract everything up to the last turn"""
+        total_msg_len = len(prompt["chosen"])
+        total_msg_turns, remainder = divmod(total_msg_len, 2)
+        assert remainder == 0, "invalid number of turns"
+
+        messages: List[Message] = []
+        if system := prompt.get("system", None):
+            messages.append(Message(role="system", content=system, label=False))
+        for i in range(total_msg_turns):
+            if "prompt" in prompt:
+                messages.append(
+                    Message(role="user", content=prompt["prompt"], label=False)
+                )
+            else:
+                messages.append(
+                    Message(
+                        role="user",
+                        content=prompt["chosen"][i * 2]["content"],
+                        label=False,
+                    )
+                )
+            if i < total_msg_turns - 1:
+                messages.append(
+                    Message(
+                        role="assistant",
+                        content=prompt["chosen"][i * 2 + 1]["content"],
+                        label=False,
+                    )
+                )
+
+        return MessageList(messages=messages)
+
+    def get_chosen(self, prompt) -> MessageList:
+        res = self.get_prompt(prompt)
+        res.messages.append(
+            Message(
+                role="assistant", content=prompt["chosen"][-1]["content"], label=True
+            )
+        )
+        return res
+
+    def get_rejected(self, prompt) -> MessageList:
+        res = self.get_prompt(prompt)
+        res.messages.append(
+            Message(
+                role="assistant", content=prompt["rejected"][-1]["content"], label=True
+            )
+        )
+        return res
+
 
 class ORPOTokenizingStrategy(PromptTokenizingStrategy):
     """
@@ -186,3 +237,36 @@ class ORPOPrompter(Prompter):
                     chat_template=self.chat_template,
                     tokenize=False,
                 ), True
+
+
+def argilla(cfg, **kwargs):  # pylint: disable=possibly-unused-variable,unused-argument
+    dataset_parser = ORPODatasetParsingStrategy()
+
+    chat_template_str = chat_templates(cfg.chat_template)
+
+    def transform_fn(sample, tokenizer=None):
+        res = {}
+
+        res["prompt"] = tokenizer.apply_chat_template(
+            [msg.model_dump() for msg in dataset_parser.get_prompt(sample).messages],
+            add_generation_prompt=True,
+            chat_template=chat_template_str,
+            tokenize=False,
+        )
+        prompt_str_len = len(res["prompt"])
+        res["chosen"] = tokenizer.apply_chat_template(
+            [msg.model_dump() for msg in dataset_parser.get_chosen(sample).messages],
+            add_generation_prompt=False,
+            chat_template=chat_template_str,
+            tokenize=False,
+        )[prompt_str_len:]
+        res["rejected"] = tokenizer.apply_chat_template(
+            [msg.model_dump() for msg in dataset_parser.get_rejected(sample).messages],
+            add_generation_prompt=False,
+            chat_template=chat_template_str,
+            tokenize=False,
+        )[prompt_str_len:]
+
+        return res
+
+    return transform_fn

src/axolotl/utils/data/__init__.py

@@ -1,11 +1,11 @@
 """
 Data processing modules
 """
-from axolotl.utils.data.dpo import load_prepare_dpo_datasets  # noqa: F401
 from axolotl.utils.data.pretraining import (  # noqa: F401
     encode_pretraining,
     wrap_pretraining_dataset,
 )
+from axolotl.utils.data.rl import load_prepare_dpo_datasets  # noqa: F401
 from axolotl.utils.data.sft import (  # noqa: F401
     get_dataset_wrapper,
     load_prepare_datasets,

src/axolotl/utils/data/{dpo.py → rl.py}

@@ -1,17 +1,20 @@
 """data handling specific to DPO"""
-
+import inspect
 import logging
+from functools import partial
 from pathlib import Path
 from typing import Any, List
 
 import yaml
-from datasets import concatenate_datasets, load_dataset, load_from_disk
+from datasets import DatasetDict, concatenate_datasets, load_dataset, load_from_disk
 
 from axolotl.common.const import DEFAULT_DATASET_PREPARED_PATH
 from axolotl.prompt_strategies.dpo import load as load_dpo
+from axolotl.prompt_strategies.orpo import load as load_orpo
 from axolotl.utils.data.utils import md5
 from axolotl.utils.dict import DictDefault
 from axolotl.utils.distributed import is_main_process, zero_first
+from axolotl.utils.models import load_tokenizer
 
 LOG = logging.getLogger("axolotl")
 
@@ -72,16 +75,29 @@ def load_prepare_dpo_datasets(cfg):
                 )
                 split_datasets.insert(i, ds)
 
+        tokenizer = None
         for i, data_set in enumerate(split_datasets):
             _type = dataset_cfgs[i]["type"]
             if _type:
                 if isinstance(_type, DictDefault):
                     _type = "user_defined.default"
-                ds_transform_fn = load_dpo(_type, _cfg, dataset_idx=i)
-                split_datasets[i] = data_set.map(
+                if _cfg.rl == "orpo":
+                    ds_transform_fn = load_orpo(_type, _cfg, dataset_idx=i)
+                else:
+                    ds_transform_fn = load_dpo(_type, _cfg, dataset_idx=i)
+                sig = inspect.signature(ds_transform_fn)
+                if "tokenizer" in sig.parameters:
+                    if not tokenizer:
+                        tokenizer = load_tokenizer(_cfg)
+                    ds_transform_fn = partial(ds_transform_fn, tokenizer=tokenizer)
+
+                data_set = data_set.map(
                     ds_transform_fn,
                     desc="Mapping RL Dataset",
                 )
+                if isinstance(data_set, DatasetDict):
+                    data_set = data_set["train"]
+                split_datasets[i] = data_set
             else:
                 # If no `type` is provided, assume the dataset is already in the expected format with
                 # "prompt", "chosen" and "rejected" already preprocessed

src/axolotl/utils/trainer.py

@@ -13,7 +13,7 @@ from datasets import set_caching_enabled
 from torch.utils.data import DataLoader, RandomSampler
 from transformers.utils import is_torch_bf16_gpu_available
 
-from axolotl.core.trainer_builder import HFCausalTrainerBuilder, HFDPOTrainerBuilder
+from axolotl.core.trainer_builder import HFCausalTrainerBuilder, HFRLTrainerBuilder
 from axolotl.utils.distributed import is_main_process, reduce_and_broadcast, zero_first
 from axolotl.utils.samplers import MultipackBatchSampler, get_dataset_lengths
 
@@ -340,8 +340,8 @@ def prepare_optim_env(cfg):
 
 
 def setup_trainer(cfg, train_dataset, eval_dataset, model, tokenizer, total_num_steps):
-    if cfg.rl in ["dpo", "ipo", "kto_pair"]:
-        trainer_builder = HFDPOTrainerBuilder(cfg, model[0], tokenizer)
+    if cfg.rl in ["dpo", "ipo", "kto_pair", "orpo"]:
+        trainer_builder = HFRLTrainerBuilder(cfg, model[0], tokenizer)
         trainer_builder.model_ref = model[1]
         trainer_builder.peft_config = model[2]
     else:

tests/core/test_trainer_builder.py

@@ -4,7 +4,7 @@ unit tests for axolotl.core.trainer_builder
 
 import pytest
 
-from axolotl.core.trainer_builder import HFDPOTrainerBuilder
+from axolotl.core.trainer_builder import HFRLTrainerBuilder
 from axolotl.utils.config import normalize_config
 from axolotl.utils.dict import DictDefault
 from axolotl.utils.models import load_model, load_tokenizer
@@ -51,13 +51,13 @@ def fixture_model(cfg, tokenizer):
     return load_model(cfg, tokenizer)
 
 
-class TestHFDPOTrainerBuilder:
+class TestHFRLTrainerBuilder:
     """
     TestCase class for DPO trainer builder
     """
 
     def test_build_training_arguments(self, cfg, model, tokenizer):
-        builder = HFDPOTrainerBuilder(cfg, model, tokenizer)
+        builder = HFRLTrainerBuilder(cfg, model, tokenizer)
         training_arguments = builder.build_training_arguments(100)
         assert training_arguments.adam_beta1 == 0.998
         assert training_arguments.adam_beta2 == 0.9