thanks so much， I have implement the first method， but I don’t know how to implement the second method ，can you give  a full blown example， that will be very grateful. or you can teach me how to change my code, to achieve the second method.
this is  my code:
# Model
if opt.model == 'VGG19':
    net = VGG('VGG19')
elif opt.model  == 'Resnet18':
    net = ResNet18()

if opt.resume:
    # Load checkpoint.
    print('==> Resuming from checkpoint..')
    assert os.path.isdir(path), 'Error: no checkpoint directory found!'
    checkpoint = torch.load(os.path.join(path,'PrivateTest_model.t7'))

    net.load_state_dict(checkpoint['net'])
    best_PublicTest_acc = checkpoint['best_PublicTest_acc']
    best_PrivateTest_acc = checkpoint['best_PrivateTest_acc']
    best_PrivateTest_acc_epoch = checkpoint['best_PublicTest_acc_epoch']
    best_PrivateTest_acc_epoch = checkpoint['best_PrivateTest_acc_epoch']
    start_epoch = checkpoint['best_PrivateTest_acc_epoch'] + 1
else:
    print('==> Building model..')

if use_cuda:
    net.cuda()

criterion = nn.CrossEntropyLoss()
optimizer = optim.SGD(net.parameters(), lr=opt.lr, momentum=0.9, weight_decay=5e-4)

# Training
def train(epoch):
    print('\nEpoch: %d' % epoch)
    global Train_acc
    net.train()
    train_loss = 0
    correct = 0
    total = 0

    if epoch > learning_rate_decay_start and learning_rate_decay_start >= 0:
        frac = (epoch - learning_rate_decay_start) // learning_rate_decay_every
        decay_factor = learning_rate_decay_rate ** frac
        current_lr = opt.lr * decay_factor
        utils.set_lr(optimizer, current_lr)  # set the decayed rate
    else:
        current_lr = opt.lr
    print('learning_rate: %s' % str(current_lr))

    for batch_idx, (inputs, targets) in enumerate(trainloader):
        if use_cuda:
            inputs, targets = inputs.cuda(), targets.cuda()
        optimizer.zero_grad()
        inputs, targets = Variable(inputs), Variable(targets)
        outputs = net(inputs)
        loss = criterion(outputs, targets)
        loss.backward()
        utils.clip_gradient(optimizer, 0.1)
        optimizer.step()
        train_loss += loss.data[0]
        _, predicted = torch.max(outputs.data, 1)
        total += targets.size(0)
        correct += predicted.eq(targets.data).cpu().sum()

        utils.progress_bar(batch_idx, len(trainloader), 'Loss: %.3f | Acc: %.3f%% (%d/%d)'
            % (train_loss/(batch_idx+1), 100.*correct/total, correct, total))

    Train_acc = 100.*correct/total

def PublicTest(epoch):
    global PublicTest_acc
    global best_PublicTest_acc
    global best_PublicTest_acc_epoch
    net.eval()
    PublicTest_loss = 0
    correct = 0
    total = 0
    for batch_idx, (inputs, targets) in enumerate(PublicTestloader):
        bs, ncrops, c, h, w = np.shape(inputs)
        inputs = inputs.view(-1, c, h, w)
        if use_cuda:
            inputs, targets = inputs.cuda(), targets.cuda()
        inputs, targets = Variable(inputs, volatile=True), Variable(targets)
        outputs = net(inputs)
        outputs_avg = outputs.view(bs, ncrops, -1).mean(1)  # avg over crops
        loss = criterion(outputs_avg, targets)
        PublicTest_loss += loss.data[0]
        _, predicted = torch.max(outputs_avg.data, 1)
        total += targets.size(0)
        correct += predicted.eq(targets.data).cpu().sum()

        utils.progress_bar(batch_idx, len(PublicTestloader), 'Loss: %.3f | Acc: %.3f%% (%d/%d)'
                           % (PublicTest_loss / (batch_idx + 1), 100. * correct / total, correct, total))

    # Save checkpoint.
    PublicTest_acc = 100.*correct/total
    if PublicTest_acc > best_PublicTest_acc:
        print('Saving..')
        print("best_PublicTest_acc: %0.3f" % PublicTest_acc)
        state = {
            'net': net.state_dict() if use_cuda else net,
            'acc': PublicTest_acc,
            'epoch': epoch,
        }
        if not os.path.isdir(path):
            os.mkdir(path)
        torch.save(state, os.path.join(path,'PublicTest_model.t7'))
        best_PublicTest_acc = PublicTest_acc
        best_PublicTest_acc_epoch = epoch

def PrivateTest(epoch):
    global PrivateTest_acc
    global best_PrivateTest_acc
    global best_PrivateTest_acc_epoch
    net.eval()
    PrivateTest_loss = 0
    correct = 0
    total = 0
    for batch_idx, (inputs, targets) in enumerate(PrivateTestloader):
        bs, ncrops, c, h, w = np.shape(inputs)
        inputs = inputs.view(-1, c, h, w)
        if use_cuda:
            inputs, targets = inputs.cuda(), targets.cuda()
        inputs, targets = Variable(inputs, volatile=True), Variable(targets)
        outputs = net(inputs)
        outputs_avg = outputs.view(bs, ncrops, -1).mean(1)  # avg over crops
        loss = criterion(outputs_avg, targets)
        PrivateTest_loss += loss.data[0]
        _, predicted = torch.max(outputs_avg.data, 1)
        total += targets.size(0)
        correct += predicted.eq(targets.data).cpu().sum()

        utils.progress_bar(batch_idx, len(PublicTestloader), 'Loss: %.3f | Acc: %.3f%% (%d/%d)'
            % (PrivateTest_loss / (batch_idx + 1), 100. * correct / total, correct, total))
    # Save checkpoint.
    PrivateTest_acc = 100.*correct/total

    if PrivateTest_acc > best_PrivateTest_acc:
        print('Saving..')
        print("best_PrivateTest_acc: %0.3f" % PrivateTest_acc)
        state = {
            'net': net.state_dict() if use_cuda else net,
	        'best_PublicTest_acc': best_PublicTest_acc,
            'best_PrivateTest_acc': PrivateTest_acc,
    	    'best_PublicTest_acc_epoch': best_PublicTest_acc_epoch,
            'best_PrivateTest_acc_epoch': epoch,
        }
        if not os.path.isdir(path):
            os.mkdir(path)
        torch.save(state, os.path.join(path,'PrivateTest_model.t7'))
        best_PrivateTest_acc = PrivateTest_acc
        best_PrivateTest_acc_epoch = epoch