lightning/pl_examples/basic_examples/dali_image_classifier.py

208 lines
6.7 KiB
Python

# Copyright The PyTorch Lightning team.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License 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.
from abc import ABC
from argparse import ArgumentParser
from random import shuffle
from warnings import warn
import numpy as np
import torch
from torch.nn import functional as F
from torch.utils.data import random_split
import pytorch_lightning as pl
from pl_examples import TORCHVISION_AVAILABLE, DALI_AVAILABLE
if TORCHVISION_AVAILABLE:
from torchvision.datasets.mnist import MNIST
from torchvision import transforms
else:
from tests.base.datasets import MNIST
if DALI_AVAILABLE:
import nvidia.dali.ops as ops
from nvidia.dali.pipeline import Pipeline
from nvidia.dali.plugin.pytorch import DALIClassificationIterator
else:
warn('NVIDIA DALI is not available')
ops, Pipeline, DALIClassificationIterator = ..., ABC, ABC
class ExternalMNISTInputIterator(object):
"""
This iterator class wraps torchvision's MNIST dataset and returns the images and labels in batches
"""
def __init__(self, mnist_ds, batch_size):
self.batch_size = batch_size
self.mnist_ds = mnist_ds
self.indices = list(range(len(self.mnist_ds)))
shuffle(self.indices)
def __iter__(self):
self.i = 0
self.n = len(self.mnist_ds)
return self
def __next__(self):
batch = []
labels = []
for _ in range(self.batch_size):
index = self.indices[self.i]
img, label = self.mnist_ds[index]
batch.append(img.numpy())
labels.append(np.array([label], dtype=np.uint8))
self.i = (self.i + 1) % self.n
return (batch, labels)
class ExternalSourcePipeline(Pipeline):
"""
This DALI pipeline class just contains the MNIST iterator
"""
def __init__(self, batch_size, eii, num_threads, device_id):
super(ExternalSourcePipeline, self).__init__(batch_size, num_threads, device_id, seed=12)
self.source = ops.ExternalSource(source=eii, num_outputs=2)
self.build()
def define_graph(self):
images, labels = self.source()
return images, labels
class DALIClassificationLoader(DALIClassificationIterator):
"""
This class extends DALI's original DALIClassificationIterator with the __len__() function so that we can call len() on it
"""
def __init__(
self,
pipelines,
size=-1,
reader_name=None,
auto_reset=False,
fill_last_batch=True,
dynamic_shape=False,
last_batch_padded=False,
):
super().__init__(pipelines, size, reader_name, auto_reset, fill_last_batch, dynamic_shape, last_batch_padded)
def __len__(self):
batch_count = self._size // (self._num_gpus * self.batch_size)
last_batch = 1 if self._fill_last_batch else 0
return batch_count + last_batch
class LitClassifier(pl.LightningModule):
def __init__(self, hidden_dim=128, learning_rate=1e-3):
super().__init__()
self.save_hyperparameters()
self.l1 = torch.nn.Linear(28 * 28, self.hparams.hidden_dim)
self.l2 = torch.nn.Linear(self.hparams.hidden_dim, 10)
def forward(self, x):
x = x.view(x.size(0), -1)
x = torch.relu(self.l1(x))
x = torch.relu(self.l2(x))
return x
def split_batch(self, batch):
return batch[0]["data"], batch[0]["label"].squeeze().long()
def training_step(self, batch, batch_idx):
x, y = self.split_batch(batch)
y_hat = self(x)
loss = F.cross_entropy(y_hat, y)
return loss
def validation_step(self, batch, batch_idx):
x, y = self.split_batch(batch)
y_hat = self(x)
loss = F.cross_entropy(y_hat, y)
self.log('valid_loss', loss)
def test_step(self, batch, batch_idx):
x, y = self.split_batch(batch)
y_hat = self(x)
loss = F.cross_entropy(y_hat, y)
self.log('test_loss', loss)
def configure_optimizers(self):
return torch.optim.Adam(self.parameters(), lr=self.hparams.learning_rate)
@staticmethod
def add_model_specific_args(parent_parser):
parser = ArgumentParser(parents=[parent_parser], add_help=False)
parser.add_argument('--hidden_dim', type=int, default=128)
parser.add_argument('--learning_rate', type=float, default=0.0001)
return parser
def cli_main():
if not DALI_AVAILABLE:
return
pl.seed_everything(1234)
# ------------
# args
# ------------
parser = ArgumentParser()
parser.add_argument('--batch_size', default=32, type=int)
parser = pl.Trainer.add_argparse_args(parser)
parser = LitClassifier.add_model_specific_args(parser)
args = parser.parse_args()
# ------------
# data
# ------------
dataset = MNIST('', train=True, download=True, transform=transforms.ToTensor())
mnist_test = MNIST('', train=False, download=True, transform=transforms.ToTensor())
mnist_train, mnist_val = random_split(dataset, [55000, 5000])
eii_train = ExternalMNISTInputIterator(mnist_train, args.batch_size)
eii_val = ExternalMNISTInputIterator(mnist_val, args.batch_size)
eii_test = ExternalMNISTInputIterator(mnist_test, args.batch_size)
pipe_train = ExternalSourcePipeline(batch_size=args.batch_size, eii=eii_train, num_threads=2, device_id=0)
train_loader = DALIClassificationLoader(pipe_train, size=len(mnist_train), auto_reset=True, fill_last_batch=False)
pipe_val = ExternalSourcePipeline(batch_size=args.batch_size, eii=eii_val, num_threads=2, device_id=0)
val_loader = DALIClassificationLoader(pipe_val, size=len(mnist_val), auto_reset=True, fill_last_batch=False)
pipe_test = ExternalSourcePipeline(batch_size=args.batch_size, eii=eii_test, num_threads=2, device_id=0)
test_loader = DALIClassificationLoader(pipe_test, size=len(mnist_test), auto_reset=True, fill_last_batch=False)
# ------------
# model
# ------------
model = LitClassifier(args.hidden_dim, args.learning_rate)
# ------------
# training
# ------------
trainer = pl.Trainer.from_argparse_args(args)
trainer.fit(model, train_loader, val_loader)
# ------------
# testing
# ------------
trainer.test(test_dataloaders=test_loader)
if __name__ == "__main__":
cli_main()