# Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License").
# You may not use this file except in compliance with the License.
# A copy of the License is located at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# or in the "license" file accompanying this file. This file is distributed
# on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
# express or implied. See the License for the specific language governing
# permissions and limitations under the License.
import argparse
import json
import logging
import os
import sagemaker_containers
import sys
import torch
import torch.distributed as dist
import torch.nn as nn
import torch.nn.functional as F
import torch.optim as optim
import torch.utils.data
import torch.utils.data.distributed
from torchvision import datasets, transforms
logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)
logger.addHandler(logging.StreamHandler(sys.stdout))
# Based on https://github.com/pytorch/examples/blob/master/mnist/main.py
class Net(nn.Module):
def __init__(self):
super(Net, self).__init__()
self.conv1 = nn.Conv2d(1, 10, kernel_size=5)
self.conv2 = nn.Conv2d(10, 20, kernel_size=5)
self.conv2_drop = nn.Dropout2d()
self.fc1 = nn.Linear(320, 50)
self.fc2 = nn.Linear(50, 10)
def forward(self, x):
x = F.relu(F.max_pool2d(self.conv1(x), 2))
x = F.relu(F.max_pool2d(self.conv2_drop(self.conv2(x)), 2))
x = x.view(-1, 320)
x = F.relu(self.fc1(x))
x = F.dropout(x, training=self.training)
x = self.fc2(x)
return F.log_softmax(x, dim=1)
def _get_train_data_loader(batch_size, training_dir, is_distributed, **kwargs):
logger.info("Get train data loader")
dataset = datasets.MNIST(training_dir, train=True, transform=transforms.Compose([
transforms.ToTensor(),
transforms.Normalize((0.1307,), (0.3081,))
]))
train_sampler = torch.utils.data.distributed.DistributedSampler(dataset) if is_distributed else None
return torch.utils.data.DataLoader(dataset, batch_size=batch_size, shuffle=train_sampler is None,
sampler=train_sampler, **kwargs)
def _get_test_data_loader(test_batch_size, training_dir, **kwargs):
logger.info("Get test data loader")
return torch.utils.data.DataLoader(
datasets.MNIST(training_dir, train=False, transform=transforms.Compose([
transforms.ToTensor(),
transforms.Normalize((0.1307,), (0.3081,))
])),
batch_size=test_batch_size, shuffle=True, **kwargs)
def _average_gradients(model):
# Gradient averaging.
size = float(dist.get_world_size())
for param in model.parameters():
dist.all_reduce(param.grad.data, op=dist.reduce_op.SUM)
param.grad.data /= size
def train(args):
is_distributed = len(args.hosts) > 1 and args.backend is not None
logger.debug("Distributed training - {}".format(is_distributed))
use_cuda = args.num_gpus > 0
logger.debug("Number of gpus available - {}".format(args.num_gpus))
kwargs = {'num_workers': 1, 'pin_memory': True} if use_cuda else {}
device = torch.device("cuda" if use_cuda else "cpu")
if is_distributed:
# Initialize the distributed environment.
world_size = len(args.hosts)
os.environ['WORLD_SIZE'] = str(world_size)
host_rank = args.hosts.index(args.current_host)
os.environ['RANK'] = str(host_rank)
dist.init_process_group(backend=args.backend, rank=host_rank, world_size=world_size)
logger.info('Initialized the distributed environment: \'{}\' backend on {} nodes. '.format(
args.backend, dist.get_world_size()) + 'Current host rank is {}. Number of gpus: {}'.format(
dist.get_rank(), args.num_gpus))
# set the seed for generating random numbers
torch.manual_seed(args.seed)
if use_cuda:
torch.cuda.manual_seed(args.seed)
train_loader = _get_train_data_loader(args.batch_size, args.data_dir, is_distributed, **kwargs)
test_loader = _get_test_data_loader(args.test_batch_size, args.data_dir, **kwargs)
logger.debug("Processes {}/{} ({:.0f}%) of train data".format(
len(train_loader.sampler), len(train_loader.dataset),
100. * len(train_loader.sampler) / len(train_loader.dataset)
))
logger.debug("Processes {}/{} ({:.0f}%) of test data".format(
len(test_loader.sampler), len(test_loader.dataset),
100. * len(test_loader.sampler) / len(test_loader.dataset)
))
model = Net().to(device)
if is_distributed and use_cuda:
# multi-machine multi-gpu case
model = torch.nn.parallel.DistributedDataParallel(model)
else:
# single-machine multi-gpu case or single-machine or multi-machine cpu case
model = torch.nn.DataParallel(model)
optimizer = optim.SGD(model.parameters(), lr=args.lr, momentum=args.momentum)
for epoch in range(1, args.epochs + 1):
model.train()
for batch_idx, (data, target) in enumerate(train_loader, 1):
data, target = data.to(device), target.to(device)
optimizer.zero_grad()
output = model(data)
loss = F.nll_loss(output, target)
loss.backward()
if is_distributed and not use_cuda:
# average gradients manually for multi-machine cpu case only
_average_gradients(model)
optimizer.step()
if batch_idx % args.log_interval == 0:
logger.info('Train Epoch: {} [{}/{} ({:.0f}%)] Loss: {:.6f}'.format(
epoch, batch_idx * len(data), len(train_loader.sampler),
100. * batch_idx / len(train_loader), loss.item()))
test(model, test_loader, device)
save_model(model, args.model_dir)
def test(model, test_loader, device):
model.eval()
test_loss = 0
correct = 0
with torch.no_grad():
for data, target in test_loader:
data, target = data.to(device), target.to(device)
output = model(data)
test_loss += F.nll_loss(output, target, size_average=False).item() # sum up batch loss
pred = output.max(1, keepdim=True)[1] # get the index of the max log-probability
correct += pred.eq(target.view_as(pred)).sum().item()
test_loss /= len(test_loader.dataset)
logger.info('Test set: Average loss: {:.4f}, Accuracy: {}/{} ({:.0f}%)\n'.format(
test_loss, correct, len(test_loader.dataset),
100. * correct / len(test_loader.dataset)))
def model_fn(model_dir):
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
model = torch.nn.DataParallel(Net())
with open(os.path.join(model_dir, 'model.pth'), 'rb') as f:
model.load_state_dict(torch.load(f))
return model.to(device)
def save_model(model, model_dir):
logger.info("Saving the model.")
path = os.path.join(model_dir, 'model.pth')
# recommended way from http://pytorch.org/docs/master/notes/serialization.html
torch.save(model.cpu().state_dict(), path)
if __name__ == '__main__':
parser = argparse.ArgumentParser()
# Data and model checkpoints directories
parser.add_argument('--batch-size', type=int, default=64, metavar='N',
help='input batch size for training (default: 64)')
parser.add_argument('--test-batch-size', type=int, default=1000, metavar='N',
help='input batch size for testing (default: 1000)')
parser.add_argument('--epochs', type=int, default=10, metavar='N',
help='number of epochs to train (default: 10)')
parser.add_argument('--lr', type=float, default=0.01, metavar='LR',
help='learning rate (default: 0.01)')
parser.add_argument('--momentum', type=float, default=0.5, metavar='M',
help='SGD momentum (default: 0.5)')
parser.add_argument('--seed', type=int, default=1, metavar='S',
help='random seed (default: 1)')
parser.add_argument('--log-interval', type=int, default=100, metavar='N',
help='how many batches to wait before logging training status')
parser.add_argument('--backend', type=str, default=None,
help='backend for distributed training (tcp, gloo on cpu and gloo, nccl on gpu)')
# Container environment
parser.add_argument('--hosts', type=list, default=json.loads(os.environ['SM_HOSTS']))
parser.add_argument('--current-host', type=str, default=os.environ['SM_CURRENT_HOST'])
parser.add_argument('--model-dir', type=str, default=os.environ['SM_MODEL_DIR'])
parser.add_argument('--data-dir', type=str, default=os.environ['SM_CHANNEL_TRAINING'])
parser.add_argument('--num-gpus', type=int, default=os.environ['SM_NUM_GPUS'])
train(parser.parse_args())