ColossalAI/applications/Chat/coati/experience_buffer/utils.py

76 lines
2.3 KiB
Python

from dataclasses import dataclass
from typing import List, Optional
import torch
import torch.nn.functional as F
from coati.experience_maker.base import Experience
@dataclass
class BufferItem:
"""BufferItem is an item of experience data.
Shapes of each tensor:
sequences: (S)
action_log_probs: (A)
values: (1)
reward: (1)
advantages: (1)
attention_mask: (S)
action_mask: (A)
"A" is the number of actions.
"""
sequences: torch.Tensor
action_log_probs: torch.Tensor
values: torch.Tensor
reward: torch.Tensor
advantages: torch.Tensor
attention_mask: Optional[torch.LongTensor]
action_mask: Optional[torch.BoolTensor]
def split_experience_batch(experience: Experience) -> List[BufferItem]:
batch_size = experience.sequences.size(0)
batch_kwargs = [{} for _ in range(batch_size)]
keys = ('sequences', 'action_log_probs', 'values',
'reward', 'advantages', 'attention_mask', 'action_mask')
for key in keys:
value = getattr(experience, key)
if isinstance(value, torch.Tensor):
vals = torch.unbind(value)
else:
# None
vals = [value for _ in range(batch_size)]
assert batch_size == len(vals)
for i, v in enumerate(vals):
batch_kwargs[i][key] = v
items = [BufferItem(**kwargs) for kwargs in batch_kwargs]
return items
def _zero_pad_sequences(sequences: List[torch.Tensor], side: str = 'left') -> torch.Tensor:
assert side in ('left', 'right')
max_len = max(seq.size(0) for seq in sequences)
padded_sequences = []
for seq in sequences:
pad_len = max_len - seq.size(0)
padding = (pad_len, 0) if side == 'left' else (0, pad_len)
padded_sequences.append(F.pad(seq, padding))
return torch.stack(padded_sequences, dim=0)
def make_experience_batch(items: List[BufferItem]) -> Experience:
kwargs = {}
to_pad_keys = set(('action_log_probs', 'action_mask'))
keys = ('sequences', 'action_log_probs', 'values',
'reward', 'advantages', 'attention_mask', 'action_mask')
for key in keys:
vals = [getattr(item, key) for item in items]
if key in to_pad_keys:
batch_data = _zero_pad_sequences(vals)
else:
batch_data = torch.stack(vals, dim=0)
kwargs[key] = batch_data
return Experience(**kwargs)