train_ssd.py
from data import *
from utils.augmentations import SSDAugmentation
from layers.modules import MultiBoxLoss
from ssd import build_ssd
import os
import sys
import time
import torch
from torch.autograd import Variable
import torch.nn as nn
import torch.optim as optim
import torch.backends.cudnn as cudnn
import torch.nn.init as init
import torch.utils.data as data
import numpy as np
import argparse
def str2bool(v):
return v.lower() in ("yes", "true", "t", "1")
parser = argparse.ArgumentParser(
description='Single Shot MultiBox Detector Training With Pytorch')
train_set = parser.add_mutually_exclusive_group()
parser.add_argument('--dataset', default='VOC300', choices=['VOC300', 'VOC512'],
type=str, help='VOC300 or VOC512')
parser.add_argument('--dataset_root', default=VOC_ROOT,
help='Dataset root directory path')
parser.add_argument('--basenet', default='vgg16_reducedfc.pth',
help='Pretrained base model')
parser.add_argument('--batch_size', default=32, type=int,
help='Batch size for training')
parser.add_argument('--resume', default=None, type=str,
help='Checkpoint state_dict file to resume training from')
parser.add_argument('--start_iter', default=0, type=int,
help='Resume training at this iter')
parser.add_argument('--num_workers', default=1, type=int,
help='Number of workers used in dataloading')
parser.add_argument('--cuda', default=True, type=str2bool,
help='Use CUDA to train model')
parser.add_argument('--lr', '--learning-rate', default=1e-3, type=float,
help='initial learning rate')
parser.add_argument('--momentum', default=0.9, type=float,
help='Momentum value for optim')
parser.add_argument('--weight_decay', default=5e-4, type=float,
help='Weight decay for SGD')
parser.add_argument('--gamma', default=0.1, type=float,
help='Gamma update for SGD')
parser.add_argument('--visdom', default=False, type=str2bool,
help='Use visdom for loss visualization')
parser.add_argument('--save_folder', default='weights/',
help='Directory for saving checkpoint models')
args = parser.parse_args()
if torch.cuda.is_available():
if args.cuda:
torch.set_default_tensor_type('torch.cuda.FloatTensor')
if not args.cuda:
print("WARNING: It looks like you have a CUDA device, but aren't " +
"using CUDA.\nRun with --cuda for optimal training speed.")
torch.set_default_tensor_type('torch.FloatTensor')
else:
torch.set_default_tensor_type('torch.FloatTensor')
if not os.path.exists(args.save_folder):
os.mkdir(args.save_folder)
def train():
if args.dataset == 'COCO':
if args.dataset_root == VOC_ROOT:
if not os.path.exists(COCO_ROOT):
parser.error('Must specify dataset_root if specifying dataset')
print("WARNING: Using default COCO dataset_root because " +
"--dataset_root was not specified.")
args.dataset_root = COCO_ROOT
cfg = coco
dataset = COCODetection(root=args.dataset_root,
transform=SSDAugmentation(cfg['min_dim'],
MEANS))
elif args.dataset == 'VOC300':
if args.dataset_root == COCO_ROOT:
parser.error('Must specify dataset if specifying dataset_root')
cfg = voc300
dataset = VOCDetection(root=args.dataset_root,
transform=SSDAugmentation(cfg['min_dim'],
MEANS))
elif args.dataset == 'VOC512':
if args.dataset_root == COCO_ROOT:
parser.error('Must specify dataset if specifying dataset_root')
cfg = voc512
dataset = VOCDetection(root=args.dataset_root,
transform=SSDAugmentation(cfg['min_dim'],
MEANS))
if args.visdom:
import visdom
viz = visdom.Visdom()
ssd_net = build_ssd('train', cfg['min_dim'], cfg['num_classes'])
net = ssd_net
if args.cuda:
net = torch.nn.DataParallel(ssd_net)
cudnn.benchmark = True
if args.resume:
print('Resuming training, loading {}...'.format(args.resume))
ssd_net.load_weights(args.resume)
else:
vgg_weights = torch.load(args.save_folder + args.basenet)
print('Loading base network...')
ssd_net.vgg.load_state_dict(vgg_weights)
if args.cuda:
net = net.cuda()
if not args.resume:
print('Initializing weights...')
# initialize newly added layers' weights with xavier method
ssd_net.extras.apply(weights_init)
ssd_net.loc.apply(weights_init)
ssd_net.conf.apply(weights_init)
optimizer = optim.SGD(net.parameters(), lr=args.lr, momentum=args.momentum,
weight_decay=args.weight_decay)
criterion = MultiBoxLoss(cfg['num_classes'], 0.5, True, 0, True, 3, 0.5,
False, args.cuda)
net.train()
# loss counters
loc_loss = 0
conf_loss = 0
epoch = 0
print('Loading the dataset...')
epoch_size = len(dataset) // args.batch_size
print('Training SSD on:', dataset.name)
print('Using the specified args:')
print(args)
step_index = 0
if args.visdom:
vis_title = 'SSD.PyTorch on ' + dataset.name
vis_legend = ['Loc Loss', 'Conf Loss', 'Total Loss']
iter_plot = create_vis_plot('Iteration', 'Loss', vis_title, vis_legend)
epoch_plot = create_vis_plot('Epoch', 'Loss', vis_title, vis_legend)
data_loader = data.DataLoader(dataset, args.batch_size,
num_workers=args.num_workers,
shuffle=True, collate_fn=detection_collate,
pin_memory=True)
# create batch iterator
batch_iterator = iter(data_loader)
for iteration in range(args.start_iter, cfg['max_iter']):
if args.visdom and iteration != 0 and (iteration % epoch_size == 0):
update_vis_plot(epoch, loc_loss, conf_loss, epoch_plot, None,
'append', epoch_size)
# reset epoch loss counters
loc_loss = 0
conf_loss = 0
epoch += 1
if iteration in cfg['lr_steps']:
step_index += 1
adjust_learning_rate(optimizer, args.gamma, step_index)
# load train data
# images, targets = next(batch_iterator)
try:
images, targets = next(batch_iterator)
except StopIteration:
batch_iterator = iter(data_loader)
images, targets = next(batch_iterator)
if args.cuda:
images = Variable(images.cuda())
targets = [Variable(ann.cuda(), volatile=True) for ann in targets]
else:
images = Variable(images)
targets = [Variable(ann, volatile=True) for ann in targets]
# forward
t0 = time.time()
out = net(images)
# backprop
optimizer.zero_grad()
loss_l, loss_c = criterion(out, targets)
loss = loss_l + loss_c
loss.backward()
optimizer.step()
t1 = time.time()
loc_loss += loss_l.data#[0]
conf_loss += loss_c.data#[0]
if iteration % 10 == 0:
print('timer: %.4f sec.' % (t1 - t0))
print('iter ' + repr(iteration) + ' || Loss: %.4f ||' % (loss.data), end=' ')
# print('iter ' + repr(iteration) + ' || Loss: %.4f ||' % (loss.data[0]), end=' ')
# if args.visdom:
# update_vis_plot(iteration, loss_l.data[0], loss_c.data[0],
# iter_plot, epoch_plot, 'append')
if iteration != 0 and (iteration+1) % 10000 == 0:
print('Saving state, iter:', iteration)
torch.save(ssd_net.state_dict(), 'weights/ssd300_COCO_' +
repr(iteration) + '.pth')
torch.save(ssd_net.state_dict(),
args.save_folder + '' + args.dataset + '.pth')
def adjust_learning_rate(optimizer, gamma, step):
"""Sets the learning rate to the initial LR decayed by 10 at every
specified step
# Adapted from PyTorch Imagenet example:
# https://github.com/pytorch/examples/blob/master/imagenet/main.py
"""
lr = args.lr * (gamma ** (step))
for param_group in optimizer.param_groups:
param_group['lr'] = lr
def xavier(param):
init.xavier_uniform(param)
def weights_init(m):
if isinstance(m, nn.Conv2d):
xavier(m.weight.data)
m.bias.data.zero_()
def create_vis_plot(_xlabel, _ylabel, _title, _legend):
return viz.line(
X=torch.zeros((1,)).cpu(),
Y=torch.zeros((1, 3)).cpu(),
opts=dict(
xlabel=_xlabel,
ylabel=_ylabel,
title=_title,
legend=_legend
)
)
def update_vis_plot(iteration, loc, conf, window1, window2, update_type,
epoch_size=1):
viz.line(
X=torch.ones((1, 3)).cpu() * iteration,
Y=torch.Tensor([loc, conf, loc + conf]).unsqueeze(0).cpu() / epoch_size,
win=window1,
update=update_type
)
# initialize epoch plot on first iteration
if iteration == 0:
viz.line(
X=torch.zeros((1, 3)).cpu(),
Y=torch.Tensor([loc, conf, loc + conf]).unsqueeze(0).cpu(),
win=window2,
update=True
)
if __name__ == '__main__':
train()
