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ColossalAI/colossalai/pipeline/schedule/_utils.py

130 lines
3.3 KiB

from typing import Any, List, Optional
import torch
import torch.cuda
from torch.nn import Module
from torch.utils._pytree import tree_flatten, tree_map, tree_unflatten
def to_device(x: Any, device: Optional[torch.device] = None) -> Any:
"""Move object to device if it is a tensor.
Args:
x (Any): Object to be moved.
device (Optional[torch.device], optional): Target device. Defaults to None.
Returns:
Any: Moved object.
"""
if isinstance(x, torch.Tensor):
return x.to(device)
return x
def get_batch_size(batch: Any) -> int:
"""Get the batch size (size of dimension-0) of the first tensor in the batch.
Args:
batch (Any): Batch to be inspected.
Raises:
RuntimeError: If no tensor is found in the batch.
Returns:
int: Batch size.
"""
data_list, _ = tree_flatten(batch)
for data in data_list:
if isinstance(data, torch.Tensor):
return data.size(0)
raise RuntimeError('No tensor found in the batch')
def get_micro_batch(batch: Any, start: int, micro_batch_size: int) -> Any:
"""Get a micro batch of the original batch.
Args:
batch (Any): Batch to be sliced.
start (int): Start index of the micro batch.
micro_batch_size (int): Size of the micro batch.
Returns:
Any: Target micro batch.
"""
def _get_tensor_slice(x: Any):
if isinstance(x, torch.Tensor):
return x[start:start + micro_batch_size]
return x
return tree_map(_get_tensor_slice, batch)
def model_forward(model: Module, data: Any, internal_inputs: Optional[dict]) -> Any:
"""Call model forward function with data and internal inputs.
Args:
model (Module): Model to be called.
data (Any): Data loaded from data iterator.
internal_inputs (Optional[dict]): Data from previous stage. It must be a dict or None if it's the first stage.
Returns:
Any: Outputs of the model.
"""
if internal_inputs is None:
internal_inputs = {}
if isinstance(data, (list, tuple)):
return model(*data, **internal_inputs)
elif isinstance(data, dict):
return model(**data, **internal_inputs)
return model(data, **internal_inputs)
def retain_grad(x: Any) -> None:
"""Call retain_grad() on a tensor.
Args:
x (Any): Object to be called.
"""
if isinstance(x, torch.Tensor) and x.requires_grad:
x.retain_grad()
def detach(x: Any) -> Any:
"""Call detach() on a tensor.
Args:
x (Any): Object to be called.
Returns:
Any: The detached object.
"""
if isinstance(x, torch.Tensor):
return x.detach()
return x
def merge_batch(data: List[Any]) -> Any:
"""Merge micro batches into a batch.
Args:
data (List[Any]): A list of micro batches.
Returns:
Any: Merge batch.
"""
if len(data) == 0:
return
flattened_data = []
tree_spec = None
for d in data:
elems, tree_spec = tree_flatten(d)
flattened_data.append(elems)
merged_data = []
for elem_batch in zip(*flattened_data):
if isinstance(elem_batch[0], torch.Tensor):
merged_data.append(torch.cat(elem_batch, dim=0))
else:
merged_data.append(list(elem_batch))
return tree_unflatten(merged_data, tree_spec)