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ColossalAI/colossalai/engine/schedule/_base_schedule.py

90 lines
3.1 KiB

#!/usr/bin/env python
# -*- encoding: utf-8 -*-
from abc import ABC, abstractmethod
import torch
from colossalai.core import global_context as gpc
from colossalai.logging import get_global_dist_logger
from colossalai.utils import get_current_device
class BaseSchedule(ABC):
"""A basic helper class to control the process of training or evaluation.
It mainly composes of forward_backward_step for gradient backward and
optimizer_step for parameters update.
For the convenience to enable FP16, we aggreate all codes that contain the
control of FP16 in class schedule.
"""
def __init__(self):
self.logger = get_global_dist_logger()
@staticmethod
def _move_tensor(element):
if torch.is_tensor(element):
if not element.is_cuda:
return element.to(get_current_device()).detach()
return element
def _move_to_device(self, data):
if isinstance(data, (tuple, list)):
data = tuple([self._move_tensor(d) for d in data])
elif torch.is_tensor(data):
data = data.to(get_current_device()).detach()
return data
def load_batch(self, data_iter):
"""Loads a batch from data iterator. It returns the data and labels which are
already in the same GPU as where the model's.
:return: (data, label)
:rtype: (Tensor, Tensor)
"""
if data_iter is None:
raise RuntimeError('Dataloader is not defined.')
data, label = next(data_iter)
return self._move_to_device(data), self._move_to_device(label)
def initialize(self, model, optimizer):
"""Initializes the model and the optimizer before training.
This is often used in FP16 training.
:param model: The neural network model
:param optimizer: Optimizer for updating the parameters
"""
return model, optimizer
@abstractmethod
def forward_backward_step(self,
data_iter,
model,
criterion,
optimizer=None,
forward_only=False,
grad_accum_size: int = 1,
return_loss=True):
"""The process function over a batch of dataset for training or evaluation.
:param data_iter: Data iterator of the dataset
:param model: Model used in training or evaluation
:param optimizer: Optimizer used in training or evaluation
:param criterion: Loss function
:param forward_only: If True, the process won't include backward
:param grad_accum_size: Steps of gradient accumulation
:param return_loss: If False, the loss won't be returned
"""
pass
@abstractmethod
def optimizer_step(self, model, optimizer, grad_clipping: float = 0.0):
"""Updates the parameters with the optimizer.
:param model: The neural network model
:param optimizer: Optimizer for updating the parameters
:param grad_clipping: The norm of gradient clipping
:type grad_clipping: float, optional
"""
pass