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from dataset import Garbage_Loader
from torch.utils.data import DataLoader
from torchvision import models
import torch.nn as nn
import torch.optim as optim
import torch
import time
import os
import shutil
os.environ["CUDA_VISIBLE_DEVICES"] = "0"
"""
Author : Jack Cui
Wechat : https://mp.weixin.qq.com/s/OCWwRVDFNslIuKyiCVUoTA
"""
from tensorboardX import SummaryWriter
def accuracy(output, target, topk=(1,)):
"""
计算topk的准确率
"""
with torch.no_grad():
maxk = max(topk)
batch_size = target.size(0)
_, pred = output.topk(maxk, 1, True, True)
pred = pred.t()
correct = pred.eq(target.view(1, -1).expand_as(pred))
class_to = pred[0].cpu().numpy()
res = []
for k in topk:
correct_k = correct[:k].view(-1).float().sum(0, keepdim=True)
res.append(correct_k.mul_(100.0 / batch_size))
return res, class_to
def save_checkpoint(state, is_best, filename='checkpoint.pth.tar'):
"""
根据 is_best 存模型,一般保存 valid acc 最好的模型
"""
torch.save(state, filename)
if is_best:
shutil.copyfile(filename, 'model_best_' + filename)
def train(train_loader, model, criterion, optimizer, epoch, writer):
"""
训练代码
参数:
train_loader - 训练集的 DataLoader
model - 模型
criterion - 损失函数
optimizer - 优化器
epoch - 进行第几个 epoch
writer - 用于写 tensorboardX
"""
batch_time = AverageMeter()
data_time = AverageMeter()
losses = AverageMeter()
top1 = AverageMeter()
top5 = AverageMeter()
# switch to train mode
model.train()
end = time.time()
for i, (input, target) in enumerate(train_loader):
# measure data loading time
data_time.update(time.time() - end)
input = input.cuda()
target = target.cuda()
# compute output
output = model(input)
loss = criterion(output, target)
# measure accuracy and record loss
[prec1, prec5], class_to = accuracy(output, target, topk=(1, 5))
losses.update(loss.item(), input.size(0))
top1.update(prec1[0], input.size(0))
top5.update(prec5[0], input.size(0))
# compute gradient and do SGD step
optimizer.zero_grad()
loss.backward()
optimizer.step()
# measure elapsed time
batch_time.update(time.time() - end)
end = time.time()
if i % 10 == 0:
print('Epoch: [{0}][{1}/{2}]\t'
'Time {batch_time.val:.3f} ({batch_time.avg:.3f})\t'
'Data {data_time.val:.3f} ({data_time.avg:.3f})\t'
'Loss {loss.val:.4f} ({loss.avg:.4f})\t'
'Prec@1 {top1.val:.3f} ({top1.avg:.3f})\t'
'Prec@5 {top5.val:.3f} ({top5.avg:.3f})'.format(
epoch, i, len(train_loader), batch_time=batch_time,
data_time=data_time, loss=losses, top1=top1, top5=top5))
writer.add_scalar('loss/train_loss', losses.val, global_step=epoch)
def validate(val_loader, model, criterion, epoch, writer, phase="VAL"):
"""
验证代码
参数:
val_loader - 验证集的 DataLoader
model - 模型
criterion - 损失函数
epoch - 进行第几个 epoch
writer - 用于写 tensorboardX
"""
batch_time = AverageMeter()
losses = AverageMeter()
top1 = AverageMeter()
top5 = AverageMeter()
# switch to evaluate mode
model.eval()
with torch.no_grad():
end = time.time()
for i, (input, target) in enumerate(val_loader):
input = input.cuda()
target = target.cuda()
# compute output
output = model(input)
loss = criterion(output, target)
# measure accuracy and record loss
[prec1, prec5], class_to = accuracy(output, target, topk=(1, 5))
losses.update(loss.item(), input.size(0))
top1.update(prec1[0], input.size(0))
top5.update(prec5[0], input.size(0))
# measure elapsed time
batch_time.update(time.time() - end)
end = time.time()
if i % 10 == 0:
print('Test-{0}: [{1}/{2}]\t'
'Time {batch_time.val:.3f} ({batch_time.avg:.3f})\t'
'Loss {loss.val:.4f} ({loss.avg:.4f})\t'
'Prec@1 {top1.val:.3f} ({top1.avg:.3f})\t'
'Prec@5 {top5.val:.3f} ({top5.avg:.3f})'.format(
phase, i, len(val_loader),
batch_time=batch_time,
loss=losses,
top1=top1, top5=top5))
print(' * {} Prec@1 {top1.avg:.3f} Prec@5 {top5.avg:.3f}'
.format(phase, top1=top1, top5=top5))
writer.add_scalar('loss/valid_loss', losses.val, global_step=epoch)
return top1.avg, top5.avg
class AverageMeter(object):
"""Computes and stores the average and current value"""
def __init__(self):
self.reset()
def reset(self):
self.val = 0
self.avg = 0
self.sum = 0
self.count = 0
def update(self, val, n=1):
self.val = val
self.sum += val * n
self.count += n
self.avg = self.sum / self.count
if __name__ == "__main__":
# -------------------------------------------- step 1/4 : 加载数据 ---------------------------
train_dir_list = 'train.txt'
valid_dir_list = 'val.txt'
batch_size = 64
epochs = 80
num_classes = 214
train_data = Garbage_Loader(train_dir_list, train_flag=True)
valid_data = Garbage_Loader(valid_dir_list, train_flag=False)
train_loader = DataLoader(dataset=train_data, num_workers=8, pin_memory=True, batch_size=batch_size, shuffle=True)
valid_loader = DataLoader(dataset=valid_data, num_workers=8, pin_memory=True, batch_size=batch_size)
train_data_size = len(train_data)
print('训练集数量:%d' % train_data_size)
valid_data_size = len(valid_data)
print('验证集数量:%d' % valid_data_size)
# ------------------------------------ step 2/4 : 定义网络 ------------------------------------
model = models.resnet50(pretrained=True)
fc_inputs = model.fc.in_features
model.fc = nn.Linear(fc_inputs, num_classes)
model = model.cuda()
# ------------------------------------ step 3/4 : 定义损失函数和优化器等 -------------------------
lr_init = 0.0001
lr_stepsize = 20
weight_decay = 0.001
criterion = nn.CrossEntropyLoss().cuda()
optimizer = optim.Adam(model.parameters(), lr=lr_init, weight_decay=weight_decay)
scheduler = torch.optim.lr_scheduler.StepLR(optimizer, step_size=lr_stepsize, gamma=0.1)
writer = SummaryWriter('runs/resnet50')
# ------------------------------------ step 4/4 : 训练 -----------------------------------------
best_prec1 = 0
for epoch in range(epochs):
scheduler.step()
train(train_loader, model, criterion, optimizer, epoch, writer)
# 在验证集上测试效果
valid_prec1, valid_prec5 = validate(valid_loader, model, criterion, epoch, writer, phase="VAL")
is_best = valid_prec1 > best_prec1
best_prec1 = max(valid_prec1, best_prec1)
save_checkpoint({
'epoch': epoch + 1,
'arch': 'resnet50',
'state_dict': model.state_dict(),
'best_prec1': best_prec1,
'optimizer' : optimizer.state_dict(),
}, is_best,
filename='checkpoint_resnet50.pth.tar')
writer.close()
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