feature(whl): add AWR algorithm (#828)

* init commit

* reformat

* polish

* polish readme

* reformat

* polish

README.md

@@ -58,7 +58,7 @@ It provides **python-first** and **asynchronous-native** task and middleware abs
 - Offline RL algorithms: BCQ, CQL, TD3BC, Decision Transformer, EDAC, Diffuser, Decision Diffuser, SO2
 - Model-based RL algorithms: SVG, STEVE, MBPO, DDPPO, DreamerV3
 - Exploration algorithms: HER, RND, ICM, NGU
-- LLM + RL Algorithms: PPO-max, DPO, PromptPG
+- LLM + RL Algorithms: PPO-max, DPO, PromptPG, PromptAWR
 - Other algorithms: such as PER, PLR, PCGrad
 - MCTS + RL algorithms: AlphaZero, MuZero, please refer to [LightZero](https://github.com/opendilab/LightZero)
 - Generative Model + RL algorithms: Diffusion-QL, QGPO, SRPO, please refer to [GenerativeRL](https://github.com/opendilab/GenerativeRL)
@@ -283,6 +283,7 @@ P.S: The `.py` file in `Runnable Demo` can be found in `dizoo`
 | 54 |                                           [ST-DIM](https://arxiv.org/pdf/1906.08226.pdf)                                           |                                                            ![other](https://img.shields.io/badge/-other-lightgrey)                                                            |                                                                              [torch_utils/loss/contrastive_loss](https://github.com/opendilab/DI-engine/blob/main/ding/torch_utils/loss/contrastive_loss.py)                                                                              |                   ding -m serial -c cartpole_dqn_stdim_config.py -s 0                   |
 | 55 |                                             [PLR](https://arxiv.org/pdf/2010.03934.pdf)                                             |                                                            ![other](https://img.shields.io/badge/-other-lightgrey)                                                            |                                       [PLR doc](https://di-engine-docs.readthedocs.io/en/latest/12_policies/plr.html)<br>[data/level_replay/level_sampler](https://github.com/opendilab/DI-engine/blob/main/ding/data/level_replay/level_sampler.py)                                       |                          python3 -u bigfish_plr_config.py -s 0                          |
 | 56 |                                           [PCGrad](https://arxiv.org/pdf/2001.06782.pdf)                                           |                                                            ![other](https://img.shields.io/badge/-other-lightgrey)                                                            |                                                                             [torch_utils/optimizer_helper/PCGrad](https://github.com/opendilab/DI-engine/blob/main/ding/data/torch_utils/optimizer_helper.py)                                                                             |                        python3 -u multi_mnist_pcgrad_main.py -s 0                        |
+| 57 |                                           [AWR](https://arxiv.org/pdf/1910.00177)                                                   |                                                            ![discrete](https://img.shields.io/badge/-discrete-brightgreen)                                                    |                                                                             [policy/ibc](https://github.com/opendilab/DI-engine/blob/main/ding/policy/prompt_awr.py)                                                                                                                     |                        python3 -u tabmwp_awr_config.py                                   |
 
 </details>
 

ding/model/template/language_transformer.py

@@ -1,4 +1,4 @@
-from typing import List, Dict
+from typing import List, Dict, Optional
 import torch
 from torch import nn
 
@@ -15,31 +15,44 @@ class LanguageTransformer(nn.Module):
     """
     Overview:
         The LanguageTransformer network. Download a pre-trained language model and add head on it.
+        In the default case, we use BERT model as the text encoder, whose bi-directional character is good
+        for obtaining the embedding of the whole sentence.
     Interfaces:
         ``__init__``, ``forward``
     """
+    mode = ['compute_actor', 'compute_critic', 'compute_actor_critic']
 
     def __init__(
             self,
             model_name: str = "bert-base-uncased",
             add_linear: bool = False,
             embedding_size: int = 128,
-            freeze_encoder: bool = True
+            freeze_encoder: bool = True,
+            hidden_dim: int = 768,
+            norm_embedding: bool = False
     ) -> None:
         """
         Overview:
             Init the LanguageTransformer Model according to input arguments.
         Arguments:
             - model_name (:obj:`str`): The base language model name in huggingface, such as "bert-base-uncased".
             - add_linear (:obj:`bool`): Whether to add a linear layer on the top of language model, defaults to be \
-            ``False``.
+                ``False``.
             - embedding_size (:obj:`int`): The embedding size of the added linear layer, such as 128.
             - freeze_encoder (:obj:`bool`): Whether to freeze the encoder language model while training, \
-            defaults to be ``True``.
+                defaults to be ``True``.
+            - hidden_dim (:obj:`int`): The embedding dimension of the encoding model (e.g. BERT). This value should \
+                correspond to the model you use. For bert-base-uncased, this value is 768.
+            - norm_embedding (:obj:`bool`): Whether to normalize the embedding vectors. Default to be ``False``.
         """
         super().__init__()
         self.tokenizer = AutoTokenizer.from_pretrained(model_name)
         self.model = AutoModelForTokenClassification.from_pretrained(model_name)
+        in_channel = hidden_dim if not add_linear else embedding_size
+        self.value_head = nn.Linear(in_channel, 1)
+        self.norm = nn.Identity() if not norm_embedding else nn.LayerNorm(
+            normalized_shape=in_channel, elementwise_affine=False
+        )
 
         # Freeze transformer encoder and only train the linear layer
         if freeze_encoder:
@@ -49,9 +62,7 @@ def __init__(
         if add_linear:
             # Add a small, adjustable linear layer on top of language model tuned through RL
             self.embedding_size = embedding_size
-            self.linear = nn.Linear(
-                self.model.config.hidden_size, embedding_size
-            )  # 768 for bert-base-uncased, distilbert-base-uncased
+            self.linear = nn.Linear(self.model.config.hidden_size, embedding_size)
         else:
             self.linear = None
 
@@ -66,19 +77,27 @@ def _calc_embedding(self, x: list) -> torch.Tensor:
         last_hidden_states = output.hidden_states[-1]
         # Get [CLS] hidden states
         sentence_embedding = last_hidden_states[:, 0, :]  # len(input_list) x hidden_size
+        sentence_embedding = self.norm(sentence_embedding)
 
         if self.linear:
             sentence_embedding = self.linear(sentence_embedding)  # len(input_list) x embedding_size
 
         return sentence_embedding
 
-    def forward(self, train_samples: List[str], candidate_samples: List[str]) -> Dict:
+    def forward(
+            self,
+            train_samples: List[str],
+            candidate_samples: Optional[List[str]] = None,
+            mode: str = 'compute_actor'
+    ) -> Dict:
         """
         Overview:
             LanguageTransformer forward computation graph, input two lists of strings and predict their matching scores.
+            Different ``mode`` will forward with different network modules to get different outputs.
         Arguments:
             - train_samples (:obj:`List[str]`): One list of strings.
-            - candidate_samples (:obj:`List[str]`): The other list of strings to calculate the matching scores.
+            - candidate_samples (:obj:`Optional[List[str]]`): The other list of strings to calculate matching scores.
+            - - mode (:obj:`str`): The forward mode, all the modes are defined in the beginning of this class.
         Returns:
             - output (:obj:`Dict`): Output dict data, including the logit of matching scores and the \
             corresponding ``torch.distributions.Categorical`` object.
@@ -96,7 +115,15 @@ def forward(self, train_samples: List[str], candidate_samples: List[str]) -> Dic
             >>> scores = model(ctxt_list, cands_list)
             >>> assert scores.shape == (1, 3)
         """
+        assert mode in self.mode
         prompt_embedding = self._calc_embedding(train_samples)
-        cands_embedding = self._calc_embedding(candidate_samples)
-        scores = torch.mm(prompt_embedding, cands_embedding.t())
-        return {'dist': torch.distributions.Categorical(logits=scores), 'logit': scores}
+
+        res_dict = {}
+        if mode in ['compute_actor', 'compute_actor_critic']:
+            cands_embedding = self._calc_embedding(candidate_samples)
+            scores = torch.mm(prompt_embedding, cands_embedding.t())
+            res_dict.update({'dist': torch.distributions.Categorical(logits=scores), 'logit': scores})
+        if mode in ['compute_critic', 'compute_actor_critic']:
+            value = self.value_head(prompt_embedding)
+            res_dict.update({'value': value})
+        return res_dict

ding/model/template/tests/test_language_transformer.py

@@ -17,9 +17,33 @@ def check_model(self):
         cands_list = [problems[pid] for pid in cand_pids]
 
         model = LanguageTransformer(model_name="bert-base-uncased", add_linear=True, embedding_size=256)
-        scores = model(ctxt_list, cands_list)
-        assert scores.shape == (1, 3)
+        output = model(ctxt_list, cands_list, mode='compute_actor')
+        assert 'dist' in output.keys() and 'logit' in output.keys() and len(output.keys()) == 2
+        assert output['logit'].shape == (1, 3)
 
-        model = LanguageTransformer(model_name="bert-base-uncased", add_linear=False, embedding_size=256)
-        scores = model(ctxt_list, cands_list)
-        assert scores.shape == (1, 3)
+        output = model(ctxt_list, cands_list, mode='compute_critic')
+        assert 'value' in output.keys() and len(output.keys()) == 1
+        assert output['value'].shape == (1, )
+
+        output = model(ctxt_list, cands_list, mode='compute_critic')
+        assert 'value' in output.keys() and 'dist' in output.keys() and 'logit' in output.keys() and len(
+            output.keys()
+        ) == 3
+        assert output['value'].shape == (1, )
+        assert output['logit'].shape == (1, 3)
+
+        model = LanguageTransformer(model_name="bert-base-uncased", add_linear=False, norm_embedding=True)
+        output = model(ctxt_list, cands_list, mode='compute_actor')
+        assert 'dist' in output.keys() and 'logit' in output.keys() and len(output.keys()) == 2
+        assert output['logit'].shape == (1, 3)
+
+        output = model(ctxt_list, cands_list, mode='compute_critic')
+        assert 'value' in output.keys() and len(output.keys()) == 1
+        assert output['value'].shape == (1, )
+
+        output = model(ctxt_list, cands_list, mode='compute_critic')
+        assert 'value' in output.keys() and 'dist' in output.keys() and 'logit' in output.keys() and len(
+            output.keys()
+        ) == 3
+        assert output['value'].shape == (1, )
+        assert output['logit'].shape == (1, 3)

ding/policy/__init__.py

@@ -56,4 +56,5 @@
 # new-type policy
 from .ppof import PPOFPolicy
 from .prompt_pg import PromptPGPolicy
+from .prompt_awr import PromptAWRPolicy
 from .happo import HAPPOPolicy

ding/policy/command_mode_policy_instance.py

@@ -52,6 +52,7 @@
 from .prompt_pg import PromptPGPolicy
 from .plan_diffuser import PDPolicy
 from .happo import HAPPOPolicy
+from .prompt_awr import PromptAWRPolicy
 
 
 class EpsCommandModePolicy(CommandModePolicy):
@@ -455,3 +456,8 @@ def _get_setting_eval(self, command_info: dict) -> dict:
 @POLICY_REGISTRY.register('prompt_pg_command')
 class PromptPGCommandModePolicy(PromptPGPolicy, DummyCommandModePolicy):
     pass
+
+
+@POLICY_REGISTRY.register('prompt_awr_command')
+class PromptAWRCommandModePolicy(PromptAWRPolicy, DummyCommandModePolicy):
+    pass