def main():
    """Create the model and start the training."""

    device = torch.device("cuda" if not args.cpu else "cpu")

    w, h = map(int, args.input_size.split(','))
    input_size = (w, h)

    w, h = map(int, args.input_size_target.split(','))
    input_size_target = (w, h)

    cudnn.enabled = True

    # Create network
    if args.model == 'DeepLab':
        model = DeeplabMulti(num_classes=args.num_classes)
        if args.restore_from[:4] == 'http' :
            saved_state_dict = model_zoo.load_url(args.restore_from)
        else:
            saved_state_dict = torch.load(args.restore_from)

        new_params = model.state_dict().copy()
        for i in saved_state_dict:
            # Scale.layer5.conv2d_list.3.weight
            i_parts = i.split('.')
            # print i_parts
            if not args.num_classes == 19 or not i_parts[1] == 'layer5':
                new_params['.'.join(i_parts[1:])] = saved_state_dict[i]
                # print i_parts
        model.load_state_dict(new_params)

    model.train()
    model.to(device)

    cudnn.benchmark = True

    # init D
    model_D1 = FCDiscriminator(num_classes=args.num_classes).to(device)
    model_D2 = FCDiscriminator(num_classes=args.num_classes).to(device)

    model_D1.train()
    model_D1.to(device)

    model_D2.train()
    model_D2.to(device)

    if not os.path.exists(args.snapshot_dir):
        os.makedirs(args.snapshot_dir)

    trainloader = data.DataLoader(
        GTA5DataSet(args.data_dir, args.data_list, max_iters=args.num_steps * args.iter_size * args.batch_size,
                    crop_size=input_size,
                    scale=args.random_scale, mirror=args.random_mirror, mean=IMG_MEAN),
        batch_size=args.batch_size, shuffle=True, num_workers=args.num_workers, pin_memory=True)

    trainloader_iter = enumerate(trainloader)

    targetloader = data.DataLoader(cityscapesDataSet(args.data_dir_target, args.data_list_target,
                                                     max_iters=args.num_steps * args.iter_size * args.batch_size,
                                                     crop_size=input_size_target,
                                                     scale=False, mirror=args.random_mirror, mean=IMG_MEAN,
                                                     set=args.set),
                                   batch_size=args.batch_size, shuffle=True, num_workers=args.num_workers,
                                   pin_memory=True)


    targetloader_iter = enumerate(targetloader)

    # implement model.optim_parameters(args) to handle different models' lr setting

    optimizer = optim.SGD(model.optim_parameters(args),
                          lr=args.learning_rate, momentum=args.momentum, weight_decay=args.weight_decay)
    optimizer.zero_grad()

    optimizer_D1 = optim.Adam(model_D1.parameters(), lr=args.learning_rate_D, betas=(0.9, 0.99))
    optimizer_D1.zero_grad()

    optimizer_D2 = optim.Adam(model_D2.parameters(), lr=args.learning_rate_D, betas=(0.9, 0.99))
    optimizer_D2.zero_grad()

    if args.gan == 'Vanilla':
        bce_loss = torch.nn.BCEWithLogitsLoss()
    elif args.gan == 'LS':
        bce_loss = torch.nn.MSELoss()
    seg_loss = torch.nn.CrossEntropyLoss(ignore_index=255)

    interp = nn.Upsample(size=(input_size[1], input_size[0]), mode='bilinear', align_corners=True)
    interp_target = nn.Upsample(size=(input_size_target[1], input_size_target[0]), mode='bilinear', align_corners=True)

    # labels for adversarial training
    source_label = 0
    target_label = 1

    # set up tensor board
    if args.tensorboard:
        if not os.path.exists(args.log_dir):
            os.makedirs(args.log_dir)

        writer = SummaryWriter(args.log_dir)

    for i_iter in range(args.num_steps):

        loss_seg_value1 = 0
        loss_adv_target_value1 = 0
        loss_D_value1 = 0

        loss_seg_value2 = 0
        loss_adv_target_value2 = 0
        loss_D_value2 = 0

        optimizer.zero_grad()
        adjust_learning_rate(optimizer, i_iter)

        optimizer_D1.zero_grad()
        optimizer_D2.zero_grad()
        adjust_learning_rate_D(optimizer_D1, i_iter)
        adjust_learning_rate_D(optimizer_D2, i_iter)

        for sub_i in range(args.iter_size):

            # train G

            # don't accumulate grads in D
            for param in model_D1.parameters():
                param.requires_grad = False

            for param in model_D2.parameters():
                param.requires_grad = False

            # train with source

            _, batch = trainloader_iter.__next__()

            images, labels, _, _ = batch
            images = images.to(device)
            labels = labels.long().to(device)

            pred1, pred2 = model(images)
            pred1 = interp(pred1)
            pred2 = interp(pred2)

            loss_seg1 = seg_loss(pred1, labels)
            loss_seg2 = seg_loss(pred2, labels)
            loss = loss_seg2 + args.lambda_seg * loss_seg1

            # proper normalization
            loss = loss / args.iter_size
            loss.backward()
            loss_seg_value1 += loss_seg1.item() / args.iter_size
            loss_seg_value2 += loss_seg2.item() / args.iter_size

            # train with target

            _, batch = targetloader_iter.__next__()
            images, _, _ = batch
            images = images.to(device)

            pred_target1, pred_target2 = model(images)
            pred_target1 = interp_target(pred_target1)
            pred_target2 = interp_target(pred_target2)

            D_out1 = model_D1(F.softmax(pred_target1))
            D_out2 = model_D2(F.softmax(pred_target2))

            loss_adv_target1 = bce_loss(D_out1, torch.FloatTensor(D_out1.data.size()).fill_(source_label).to(device))

            loss_adv_target2 = bce_loss(D_out2, torch.FloatTensor(D_out2.data.size()).fill_(source_label).to(device))

            loss = args.lambda_adv_target1 * loss_adv_target1 + args.lambda_adv_target2 * loss_adv_target2
            loss = loss / args.iter_size
            loss.backward()
            loss_adv_target_value1 += loss_adv_target1.item() / args.iter_size
            loss_adv_target_value2 += loss_adv_target2.item() / args.iter_size

            # train D

            # bring back requires_grad
            for param in model_D1.parameters():
                param.requires_grad = True

            for param in model_D2.parameters():
                param.requires_grad = True

            # train with source
            pred1 = pred1.detach()
            pred2 = pred2.detach()

            D_out1 = model_D1(F.softmax(pred1))
            D_out2 = model_D2(F.softmax(pred2))

            loss_D1 = bce_loss(D_out1, torch.FloatTensor(D_out1.data.size()).fill_(source_label).to(device))

            loss_D2 = bce_loss(D_out2, torch.FloatTensor(D_out2.data.size()).fill_(source_label).to(device))

            loss_D1 = loss_D1 / args.iter_size / 2
            loss_D2 = loss_D2 / args.iter_size / 2

            loss_D1.backward()
            loss_D2.backward()

            loss_D_value1 += loss_D1.item()
            loss_D_value2 += loss_D2.item()

            # train with target
            pred_target1 = pred_target1.detach()
            pred_target2 = pred_target2.detach()

            D_out1 = model_D1(F.softmax(pred_target1))
            D_out2 = model_D2(F.softmax(pred_target2))

            loss_D1 = bce_loss(D_out1, torch.FloatTensor(D_out1.data.size()).fill_(target_label).to(device))

            loss_D2 = bce_loss(D_out2, torch.FloatTensor(D_out2.data.size()).fill_(target_label).to(device))

            loss_D1 = loss_D1 / args.iter_size / 2
            loss_D2 = loss_D2 / args.iter_size / 2

            loss_D1.backward()
            loss_D2.backward()

            loss_D_value1 += loss_D1.item()
            loss_D_value2 += loss_D2.item()

        optimizer.step()
        optimizer_D1.step()
        optimizer_D2.step()

        if args.tensorboard:
            scalar_info = {
                'loss_seg1': loss_seg_value1,
                'loss_seg2': loss_seg_value2,
                'loss_adv_target1': loss_adv_target_value1,
                'loss_adv_target2': loss_adv_target_value2,
                'loss_D1': loss_D_value1,
                'loss_D2': loss_D_value2,
            }

            if i_iter % 10 == 0:
                for key, val in scalar_info.items():
                    writer.add_scalar(key, val, i_iter)

        print('exp = {}'.format(args.snapshot_dir))
        print(
        'iter = {0:8d}/{1:8d}, loss_seg1 = {2:.3f} loss_seg2 = {3:.3f} loss_adv1 = {4:.3f}, loss_adv2 = {5:.3f} loss_D1 = {6:.3f} loss_D2 = {7:.3f}'.format(
            i_iter, args.num_steps, loss_seg_value1, loss_seg_value2, loss_adv_target_value1, loss_adv_target_value2, loss_D_value1, loss_D_value2))

        if i_iter >= args.num_steps_stop - 1:
            print('save model ...')
            torch.save(model.state_dict(), osp.join(args.snapshot_dir, 'GTA5_' + str(args.num_steps_stop) + '.pth'))
            torch.save(model_D1.state_dict(), osp.join(args.snapshot_dir, 'GTA5_' + str(args.num_steps_stop) + '_D1.pth'))
            torch.save(model_D2.state_dict(), osp.join(args.snapshot_dir, 'GTA5_' + str(args.num_steps_stop) + '_D2.pth'))
            break

        if i_iter % args.save_pred_every == 0 and i_iter != 0:
            print('taking snapshot ...')
            torch.save(model.state_dict(), osp.join(args.snapshot_dir, 'GTA5_' + str(i_iter) + '.pth'))
            torch.save(model_D1.state_dict(), osp.join(args.snapshot_dir, 'GTA5_' + str(i_iter) + '_D1.pth'))
            torch.save(model_D2.state_dict(), osp.join(args.snapshot_dir, 'GTA5_' + str(i_iter) + '_D2.pth'))

    if args.tensorboard:
        writer.close()
def main():

    h, w = map(int, args.input_size.split(','))
    input_size = (h, w)

    cudnn.enabled = True
    gpu = args.gpu

    # Define network
    model = DeeplabMulti(num_classes=args.num_classes)
    # model = Res_Deeplab(num_classes=args.num_classes)

    # load pretrained parameters
    if args.restore_from[:4] == 'http' :
        saved_state_dict = model_zoo.load_url(args.restore_from)
    else:
        saved_state_dict = torch.load(args.restore_from)

    # only copy the params that exist in current model (caffe-like)
    new_params = model.state_dict().copy()
    for name, param in new_params.items():
        print(name)
        if name in saved_state_dict and param.size() == saved_state_dict[name].size():
            new_params[name].copy_(saved_state_dict[name])
            print('copy {}'.format(name))
    model.load_state_dict(new_params)


    model.train()
    model.cuda()

    cudnn.benchmark = True

    # init D
    model_D = FCDiscriminator(num_classes=args.num_classes)
    if args.restore_from_D is not None:
        model_D.load_state_dict(torch.load(args.restore_from_D))
    model_D.train()
    model_D.cuda(args.gpu)


    if not os.path.exists(args.snapshot_dir):
        os.makedirs(args.snapshot_dir)

    train_dataset = cityscapesDataSet(max_iters=args.num_steps * args.iter_size * args.batch_size,
                                      scale=args.random_scale)
    train_dataset_size = len(train_dataset)
    train_gt_dataset = cityscapesDataSet(max_iters=args.num_steps * args.iter_size * args.batch_size,
                                         scale=args.random_scale)

    if args.partial_data is None:
        trainloader = data.DataLoader(train_dataset, batch_size=args.batch_size, shuffle=True,
                                      num_workers=args.num_workers,
                                      pin_memory=True)

        trainloader_gt = data.DataLoader(train_gt_dataset,
                                         batch_size=args.batch_size, shuffle=True, num_workers=5, pin_memory=True)
    else:
        # sample partial data
        partial_size = int(args.partial_data * train_dataset_size)

        if args.partial_id is not None:
            train_ids = pickle.load(open(args.partial_id))
            print('loading train ids from {}'.format(args.partial_id))
        else:
            train_ids = list(range(train_dataset_size))
            np.random.shuffle(train_ids)

        pickle.dump(train_ids, open(osp.join(args.snapshot_dir, 'train_id.pkl'), 'wb'))

        train_sampler = data.sampler.SubsetRandomSampler(train_ids[:partial_size])
        train_remain_sampler = data.sampler.SubsetRandomSampler(train_ids[partial_size:])
        train_gt_sampler = data.sampler.SubsetRandomSampler(train_ids[:partial_size])

        trainloader = data.DataLoader(train_dataset, sampler=train_sampler, batch_size=args.batch_size, shuffle=False,
                                      num_workers=args.num_workers, pin_memory=True)
        trainloader_remain = data.DataLoader(train_dataset, sampler=train_remain_sampler, batch_size=args.batch_size,
                                             shuffle=False,
                                             num_workers=args.num_workers,
                                             pin_memory=True)
        trainloader_gt = data.DataLoader(train_gt_dataset, sampler=train_gt_sampler, batch_size=args.batch_size,
                                         shuffle=False,
                                         num_workers=args.num_workers,
                                         pin_memory=True)

        trainloader_remain_iter = enumerate(trainloader_remain)

    trainloader_iter = enumerate(trainloader)
    trainloader_gt_iter = enumerate(trainloader_gt)


    # implement model.optim_parameters(args) to handle different models' lr setting

    # optimizer for segmentation network
    optimizer = optim.SGD(model.optim_parameters(args),
                lr=args.learning_rate, momentum=args.momentum,weight_decay=args.weight_decay)
    optimizer.zero_grad()

    # optimizer for discriminator network
    optimizer_D = optim.Adam(model_D.parameters(), lr=args.learning_rate_D, betas=(0.9,0.99))
    optimizer_D.zero_grad()

    # loss/ bilinear upsampling
    bce_loss = BCEWithLogitsLoss2d()
    bce_loss_1 = BCEWithLogitsLoss2dd()
    interp = nn.Upsample(size=(input_size[1], input_size[0]), mode='bilinear')

    if version.parse(torch.__version__) >= version.parse('0.4.0'):
        interp = nn.Upsample(size=(input_size[1], input_size[0]), mode='bilinear', align_corners=True)
    else:
        interp = nn.Upsample(size=(input_size[1], input_size[0]), mode='bilinear')


    # labels for adversarial training
    pred_label = 0
    gt_label = 1


    for i_iter in range(args.num_steps):

        loss_seg_value = 0
        loss_adv_pred_value = 0
        loss_D_value = 0
        loss_semi_value = 0
        loss_semi_adv_value = 0

        optimizer.zero_grad()
        adjust_learning_rate(optimizer, i_iter)
        optimizer_D.zero_grad()
        adjust_learning_rate_D(optimizer_D, i_iter)

        for sub_i in range(args.iter_size):

            # train G

            # don't accumulate grads in D
            for param in model_D.parameters():
                param.requires_grad = False

            # do semi first
            if (args.lambda_semi > 0 or args.lambda_semi_adv > 0 ) and i_iter >= args.semi_start_adv :
                try:
                    _, batch = trainloader_remain_iter.__next__()
                except:
                    trainloader_remain_iter = enumerate(trainloader_remain)
                    _, batch = trainloader_remain_iter.__next__()

                # only access to img
                images, _, _, _ = batch
                images = Variable(images).cuda(args.gpu)

                pred = interp(model(images))
                pred_remain = pred.detach()

                D_out = interp(model_D(F.softmax(pred)))
                D_out_sigmoid = F.sigmoid(D_out).data.cpu().numpy().squeeze(axis=1)

                ignore_mask_remain = np.zeros(D_out_sigmoid.shape).astype(np.bool)

                l, _, _ = bce_loss_1(D_out, make_D_label(gt_label, ignore_mask_remain))
                loss_semi_adv = args.lambda_semi_adv * -l
                loss_semi_adv = loss_semi_adv/args.iter_size

                #loss_semi_adv.backward()
                loss_semi_adv_value += loss_semi_adv.data.cpu().numpy()/args.lambda_semi_adv

                if args.lambda_semi <= 0 or i_iter < args.semi_start:
                    loss_semi_adv.backward()
                    loss_semi_value = 0
                else:
                    # produce ignore mask
                    semi_ignore_mask = (D_out_sigmoid < args.mask_T)

                    semi_gt = pred.data.cpu().numpy().argmax(axis=1)
                    semi_gt[semi_ignore_mask] = 255

                    semi_ratio = 1.0 - float(semi_ignore_mask.sum())/semi_ignore_mask.size
                    print('semi ratio: {:.4f}'.format(semi_ratio))

                    if semi_ratio == 0.0:
                        loss_semi_value += 0
                    else:
                        semi_gt = torch.FloatTensor(semi_gt)

                        loss_semi = args.lambda_semi * loss_calc(pred, semi_gt, args.gpu)
                        loss_semi = loss_semi/args.iter_size
                        loss_semi_value += loss_semi.data.cpu().numpy()/args.lambda_semi
                        loss_semi += loss_semi_adv
                        loss_semi.backward()

            else:
                loss_semi = None
                loss_semi_adv = None

            # train with source

            try:
                _, batch = trainloader_iter.__next__()
            except:
                trainloader_iter = enumerate(trainloader)
                _, batch = trainloader_iter.__next__()

            images, labels, _, _ = batch
            images = images.cuda(args.gpu)
            ignore_mask = (labels.numpy() == 255)
            pred = interp(model(images))

            loss_seg = loss_calc(pred, labels, args.gpu)

            D_out = interp(model_D(F.softmax(pred)))

            l, _, _ = bce_loss_1(D_out, make_D_label(gt_label, ignore_mask))
            loss_adv_pred = -l

            loss = loss_seg + args.lambda_adv_pred * loss_adv_pred

            # proper normalization
            loss = loss/args.iter_size
            loss.backward()
            loss_seg_value += loss_seg.data.cpu().numpy()/args.iter_size
            loss_adv_pred_value += loss_adv_pred.data.cpu().numpy()/args.iter_size


            # train D

            # bring back requires_grad
            for param in model_D.parameters():
                param.requires_grad = True

            # train with pred
            pred = pred.detach()

            if args.D_remain:
                pred = torch.cat((pred, pred_remain), 0)
                ignore_mask = np.concatenate((ignore_mask, ignore_mask_remain), axis=0)

            D_out = interp(model_D(F.softmax(pred)))
            l, p, t = bce_loss_1(D_out, make_D_label(pred_label, ignore_mask))
            gradient_penalty = compute_gradient_penalty(torch.ones_like(pred) * pred_label, pred, model_D)
            loss_D = l + 0.05 * gradient_penalty
            loss_D = loss_D/args.iter_size/2
            loss_D.backward()
            loss_D_value += loss_D.data.cpu().numpy()


            # train with gt
            # get gt labels
            try:
                _, batch = trainloader_gt_iter.__next__()
            except:
                trainloader_gt_iter = enumerate(trainloader_gt)
                _, batch = trainloader_gt_iter.__next__()

            _, labels_gt, _, _ = batch
            D_gt_v = Variable(one_hot(labels_gt)).cuda(args.gpu)
            ignore_mask_gt = (labels_gt.numpy() == 255)

            D_out = interp(model_D(D_gt_v))
            l, p, t = bce_loss_1(D_out, make_D_label(gt_label, ignore_mask_gt))
            gradient_penalty = compute_gradient_penalty(torch.ones_like(D_gt_v) * gt_label, D_gt_v, model_D)
            loss_D = -l + 0.05 * gradient_penalty
            loss_D = loss_D/args.iter_size/2
            loss_D.backward()
            loss_D_value += loss_D.data.cpu().numpy()



        optimizer.step()
        if sub_i / 5 == 0:
           optimizer_D.step()

        print('exp = {}'.format(args.snapshot_dir))
        print('iter = {0:8d}/{1:8d}, loss_seg = {2:.3f}, loss_adv_p = {3:.3f}, loss_D = {4:.3f}, loss_semi = {5:.3f}, loss_semi_adv = {6:.3f}'.format(i_iter, args.num_steps, loss_seg_value, loss_adv_pred_value, loss_D_value, loss_semi_value, loss_semi_adv_value))

        if i_iter >= args.num_steps-1:
            print('save model ...')
            torch.save(model.state_dict(),osp.join(args.snapshot_dir, 'CITY_'+str(args.num_steps)+'.pth'))
            torch.save(model_D.state_dict(),osp.join(args.snapshot_dir, 'CITY_'+str(args.num_steps)+'_D.pth'))
            break

        if i_iter % args.save_pred_every == 0 and i_iter!=0:
            print('taking snapshot ...')
            torch.save(model.state_dict(),osp.join(args.snapshot_dir, 'CITY_'+str(i_iter)+'.pth'))
            torch.save(model_D.state_dict(),osp.join(args.snapshot_dir, 'CITY_'+str(i_iter)+'_D.pth'))

    end = timeit.default_timer()
    print(end-start,'seconds')