Exemple #1
0
def train(hyp, opt, device, tb_writer=None):
    logger.info(
        colorstr('hyperparameters: ') + ', '.join(f'{k}={v}'
                                                  for k, v in hyp.items()))
    save_dir, epochs, batch_size, total_batch_size, weights, rank = \
        Path(opt.save_dir), opt.epochs, opt.batch_size, opt.total_batch_size, opt.weights, opt.global_rank

    # Directories
    wdir = save_dir / 'weights'
    wdir.mkdir(parents=True, exist_ok=True)  # make dir
    last = wdir / 'last.pt'
    best = wdir / 'best.pt'
    results_file = save_dir / 'results.txt'

    # Save run settings
    with open(save_dir / 'hyp.yaml', 'w') as f:
        yaml.dump(hyp, f, sort_keys=False)
    with open(save_dir / 'opt.yaml', 'w') as f:
        yaml.dump(vars(opt), f, sort_keys=False)

    # Configure
    plots = not opt.evolve  # create plots
    cuda = device.type != 'cpu'
    init_seeds(2 + rank)
    with open(opt.data) as f:
        data_dict = yaml.load(f, Loader=yaml.SafeLoader)  # data dict
    is_coco = opt.data.endswith('coco.yaml')

    # Logging- Doing this before checking the dataset. Might update data_dict
    loggers = {'wandb': None}  # loggers dict
    if rank in [-1, 0]:
        opt.hyp = hyp  # add hyperparameters
        run_id = torch.load(weights).get('wandb_id') if weights.endswith(
            '.pt') and os.path.isfile(weights) else None
        wandb_logger = WandbLogger(opt,
                                   Path(opt.save_dir).stem, run_id, data_dict)
        loggers['wandb'] = wandb_logger.wandb
        data_dict = wandb_logger.data_dict
        if wandb_logger.wandb:
            weights, epochs, hyp = opt.weights, opt.epochs, opt.hyp  # WandbLogger might update weights, epochs if resuming

    nc = 1 if opt.single_cls else int(data_dict['nc'])  # number of classes
    names = ['item'] if opt.single_cls and len(
        data_dict['names']) != 1 else data_dict['names']  # class names
    assert len(names) == nc, '%g names found for nc=%g dataset in %s' % (
        len(names), nc, opt.data)  # check

    # Model
    pretrained = weights.endswith('.pt')
    if pretrained:
        with torch_distributed_zero_first(rank):
            attempt_download(weights)  # download if not found locally
        ckpt = torch.load(weights, map_location=device)  # load checkpoint
        model = Model(opt.cfg or ckpt['model'].yaml,
                      ch=3,
                      nc=nc,
                      anchors=hyp.get('anchors')).to(device)  # create
        exclude = [
            'anchor'
        ] if (opt.cfg or hyp.get('anchors')) and not opt.resume else [
        ]  # exclude keys
        state_dict = ckpt['model'].float().state_dict()  # to FP32
        state_dict = intersect_dicts(state_dict,
                                     model.state_dict(),
                                     exclude=exclude)  # intersect
        model.load_state_dict(state_dict, strict=False)  # load
        logger.info(
            'Transferred %g/%g items from %s' %
            (len(state_dict), len(model.state_dict()), weights))  # report
    else:
        model = Model(opt.cfg, ch=3, nc=nc,
                      anchors=hyp.get('anchors')).to(device)  # create
    with torch_distributed_zero_first(rank):
        check_dataset(data_dict)  # check
    train_path = data_dict['train']
    test_path = data_dict['val']

    # Freeze
    freeze = []  # parameter names to freeze (full or partial)
    for k, v in model.named_parameters():
        v.requires_grad = True  # train all layers
        if any(x in k for x in freeze):
            print('freezing %s' % k)
            v.requires_grad = False

    # Optimizer
    nbs = 64  # nominal batch size
    accumulate = max(round(nbs / total_batch_size),
                     1)  # accumulate loss before optimizing
    hyp['weight_decay'] *= total_batch_size * accumulate / nbs  # scale weight_decay
    logger.info(f"Scaled weight_decay = {hyp['weight_decay']}")

    pg0, pg1, pg2 = [], [], []  # optimizer parameter groups
    for k, v in model.named_modules():
        if hasattr(v, 'bias') and isinstance(v.bias, nn.Parameter):
            pg2.append(v.bias)  # biases
        if isinstance(v, nn.BatchNorm2d):
            pg0.append(v.weight)  # no decay
        elif hasattr(v, 'weight') and isinstance(v.weight, nn.Parameter):
            pg1.append(v.weight)  # apply decay

    if opt.adam:
        optimizer = optim.Adam(pg0,
                               lr=hyp['lr0'],
                               betas=(hyp['momentum'],
                                      0.999))  # adjust beta1 to momentum
    else:
        optimizer = optim.SGD(pg0,
                              lr=hyp['lr0'],
                              momentum=hyp['momentum'],
                              nesterov=True)

    optimizer.add_param_group({
        'params': pg1,
        'weight_decay': hyp['weight_decay']
    })  # add pg1 with weight_decay
    optimizer.add_param_group({'params': pg2})  # add pg2 (biases)
    logger.info('Optimizer groups: %g .bias, %g conv.weight, %g other' %
                (len(pg2), len(pg1), len(pg0)))
    del pg0, pg1, pg2

    # Scheduler https://arxiv.org/pdf/1812.01187.pdf
    # https://pytorch.org/docs/stable/_modules/torch/optim/lr_scheduler.html#OneCycleLR
    if opt.linear_lr:
        lf = lambda x: (1 - x / (epochs - 1)) * (1.0 - hyp['lrf']) + hyp[
            'lrf']  # linear
    else:
        lf = one_cycle(1, hyp['lrf'], epochs)  # cosine 1->hyp['lrf']
    scheduler = lr_scheduler.LambdaLR(optimizer, lr_lambda=lf)
    # plot_lr_scheduler(optimizer, scheduler, epochs)

    # EMA
    ema = ModelEMA(model) if rank in [-1, 0] else None

    # Resume
    start_epoch, best_fitness = 0, 0.0
    if pretrained:
        # Optimizer
        if ckpt['optimizer'] is not None:
            optimizer.load_state_dict(ckpt['optimizer'])
            best_fitness = ckpt['best_fitness']

        # EMA
        if ema and ckpt.get('ema'):
            ema.ema.load_state_dict(ckpt['ema'].float().state_dict())
            ema.updates = ckpt['updates']

        # Results
        if ckpt.get('training_results') is not None:
            results_file.write_text(
                ckpt['training_results'])  # write results.txt

        # Epochs
        start_epoch = ckpt['epoch'] + 1
        if opt.resume:
            assert start_epoch > 0, '%s training to %g epochs is finished, nothing to resume.' % (
                weights, epochs)
        if epochs < start_epoch:
            logger.info(
                '%s has been trained for %g epochs. Fine-tuning for %g additional epochs.'
                % (weights, ckpt['epoch'], epochs))
            epochs += ckpt['epoch']  # finetune additional epochs

        del ckpt, state_dict

    # Image sizes
    gs = max(int(model.stride.max()), 32)  # grid size (max stride)
    nl = model.model[
        -1].nl  # number of detection layers (used for scaling hyp['obj'])
    imgsz, imgsz_test = [check_img_size(x, gs) for x in opt.img_size
                         ]  # verify imgsz are gs-multiples

    # DP mode
    if cuda and rank == -1 and torch.cuda.device_count() > 1:
        model = torch.nn.DataParallel(model)

    # SyncBatchNorm
    if opt.sync_bn and cuda and rank != -1:
        model = torch.nn.SyncBatchNorm.convert_sync_batchnorm(model).to(device)
        logger.info('Using SyncBatchNorm()')

    # Trainloader
    dataloader, dataset = create_dataloader(train_path,
                                            imgsz,
                                            batch_size,
                                            gs,
                                            opt,
                                            hyp=hyp,
                                            augment=True,
                                            cache=opt.cache_images,
                                            rect=opt.rect,
                                            rank=rank,
                                            world_size=opt.world_size,
                                            workers=opt.workers,
                                            image_weights=opt.image_weights,
                                            quad=opt.quad,
                                            prefix=colorstr('train: '))
    mlc = np.concatenate(dataset.labels, 0)[:, 0].max()  # max label class
    nb = len(dataloader)  # number of batches
    assert mlc < nc, 'Label class %g exceeds nc=%g in %s. Possible class labels are 0-%g' % (
        mlc, nc, opt.data, nc - 1)

    # Process 0
    if rank in [-1, 0]:
        testloader = create_dataloader(
            test_path,
            imgsz_test,
            batch_size * 2,
            gs,
            opt,  # testloader
            hyp=hyp,
            cache=opt.cache_images and not opt.notest,
            rect=True,
            rank=-1,
            world_size=opt.world_size,
            workers=opt.workers,
            pad=0.5,
            prefix=colorstr('val: '))[0]

        if not opt.resume:
            labels = np.concatenate(dataset.labels, 0)
            c = torch.tensor(labels[:, 0])  # classes
            # cf = torch.bincount(c.long(), minlength=nc) + 1.  # frequency
            # model._initialize_biases(cf.to(device))
            if plots:
                plot_labels(labels, names, save_dir, loggers)
                if tb_writer:
                    tb_writer.add_histogram('classes', c, 0)

            # Anchors
            if not opt.noautoanchor:
                check_anchors(dataset,
                              model=model,
                              thr=hyp['anchor_t'],
                              imgsz=imgsz)
            model.half().float()  # pre-reduce anchor precision

    # DDP mode
    if cuda and rank != -1:
        model = DDP(
            model,
            device_ids=[opt.local_rank],
            output_device=opt.local_rank,
            # nn.MultiheadAttention incompatibility with DDP https://github.com/pytorch/pytorch/issues/26698
            find_unused_parameters=any(
                isinstance(layer, nn.MultiheadAttention)
                for layer in model.modules()))

    # Model parameters
    hyp['box'] *= 3. / nl  # scale to layers
    hyp['cls'] *= nc / 80. * 3. / nl  # scale to classes and layers
    hyp['obj'] *= (imgsz / 640)**2 * 3. / nl  # scale to image size and layers
    hyp['label_smoothing'] = opt.label_smoothing
    model.nc = nc  # attach number of classes to model
    model.hyp = hyp  # attach hyperparameters to model
    model.gr = 1.0  # iou loss ratio (obj_loss = 1.0 or iou)
    model.class_weights = labels_to_class_weights(
        dataset.labels, nc).to(device) * nc  # attach class weights
    model.names = names

    # Start training
    t0 = time.time()
    nw = max(round(hyp['warmup_epochs'] * nb),
             1000)  # number of warmup iterations, max(3 epochs, 1k iterations)
    # nw = min(nw, (epochs - start_epoch) / 2 * nb)  # limit warmup to < 1/2 of training
    maps = np.zeros(nc)  # mAP per class
    results = (0, 0, 0, 0, 0, 0, 0
               )  # P, R, [email protected], [email protected], val_loss(box, obj, cls)
    scheduler.last_epoch = start_epoch - 1  # do not move
    scaler = amp.GradScaler(enabled=cuda)
    compute_loss = ComputeLoss(model)  # init loss class
    logger.info(f'Image sizes {imgsz} train, {imgsz_test} test\n'
                f'Using {dataloader.num_workers} dataloader workers\n'
                f'Logging results to {save_dir}\n'
                f'Starting training for {epochs} epochs...')
    for epoch in range(
            start_epoch, epochs
    ):  # epoch ------------------------------------------------------------------
        temp = f'{epoch}.pt'
        epoch_c = wdir / temp
        model.train()

        # Update image weights (optional)
        if opt.image_weights:
            # Generate indices
            if rank in [-1, 0]:
                cw = model.class_weights.cpu().numpy() * (
                    1 - maps)**2 / nc  # class weights
                iw = labels_to_image_weights(dataset.labels,
                                             nc=nc,
                                             class_weights=cw)  # image weights
                dataset.indices = random.choices(
                    range(dataset.n), weights=iw,
                    k=dataset.n)  # rand weighted idx
            # Broadcast if DDP
            if rank != -1:
                indices = (torch.tensor(dataset.indices)
                           if rank == 0 else torch.zeros(dataset.n)).int()
                dist.broadcast(indices, 0)
                if rank != 0:
                    dataset.indices = indices.cpu().numpy()

        # Update mosaic border
        # b = int(random.uniform(0.25 * imgsz, 0.75 * imgsz + gs) // gs * gs)
        # dataset.mosaic_border = [b - imgsz, -b]  # height, width borders

        mloss = torch.zeros(4, device=device)  # mean losses
        if rank != -1:
            dataloader.sampler.set_epoch(epoch)
        pbar = enumerate(dataloader)
        logger.info(
            ('\n' + '%10s' * 8) % ('Epoch', 'gpu_mem', 'box', 'obj', 'cls',
                                   'total', 'labels', 'img_size'))
        if rank in [-1, 0]:
            pbar = tqdm(pbar, total=nb)  # progress bar
        optimizer.zero_grad()
        for i, (
                imgs, targets, paths, _
        ) in pbar:  # batch -------------------------------------------------------------
            ni = i + nb * epoch  # number integrated batches (since train start)
            imgs = imgs.to(device, non_blocking=True).float(
            ) / 255.0  # uint8 to float32, 0-255 to 0.0-1.0

            # Warmup
            if ni <= nw:
                xi = [0, nw]  # x interp
                # model.gr = np.interp(ni, xi, [0.0, 1.0])  # iou loss ratio (obj_loss = 1.0 or iou)
                accumulate = max(
                    1,
                    np.interp(ni, xi, [1, nbs / total_batch_size]).round())
                for j, x in enumerate(optimizer.param_groups):
                    # bias lr falls from 0.1 to lr0, all other lrs rise from 0.0 to lr0
                    x['lr'] = np.interp(ni, xi, [
                        hyp['warmup_bias_lr'] if j == 2 else 0.0,
                        x['initial_lr'] * lf(epoch)
                    ])
                    if 'momentum' in x:
                        x['momentum'] = np.interp(
                            ni, xi, [hyp['warmup_momentum'], hyp['momentum']])

            # Multi-scale
            if opt.multi_scale:
                sz = random.randrange(imgsz * 0.5,
                                      imgsz * 1.5 + gs) // gs * gs  # size
                sf = sz / max(imgs.shape[2:])  # scale factor
                if sf != 1:
                    ns = [math.ceil(x * sf / gs) * gs for x in imgs.shape[2:]
                          ]  # new shape (stretched to gs-multiple)
                    imgs = F.interpolate(imgs,
                                         size=ns,
                                         mode='bilinear',
                                         align_corners=False)

            # Forward
            with amp.autocast(enabled=cuda):
                pred = model(imgs)  # forward
                loss, loss_items = compute_loss(
                    pred, targets.to(device))  # loss scaled by batch_size
                if rank != -1:
                    loss *= opt.world_size  # gradient averaged between devices in DDP mode
                if opt.quad:
                    loss *= 4.

            # Backward
            scaler.scale(loss).backward()

            # Optimize
            if ni % accumulate == 0:
                scaler.step(optimizer)  # optimizer.step
                scaler.update()
                optimizer.zero_grad()
                if ema:
                    ema.update(model)

            # Print
            if rank in [-1, 0]:
                mloss = (mloss * i + loss_items) / (i + 1
                                                    )  # update mean losses
                mem = '%.3gG' % (torch.cuda.memory_reserved() / 1E9
                                 if torch.cuda.is_available() else 0)  # (GB)
                s = ('%10s' * 2 +
                     '%10.4g' * 6) % ('%g/%g' % (epoch, epochs - 1), mem,
                                      *mloss, targets.shape[0], imgs.shape[-1])
                pbar.set_description(s)

                # Plot
                if plots and ni < 3:
                    f = save_dir / f'train_batch{ni}.jpg'  # filename
                    Thread(target=plot_images,
                           args=(imgs, targets, paths, f),
                           daemon=True).start()
                    # if tb_writer:
                    #     tb_writer.add_image(f, result, dataformats='HWC', global_step=epoch)
                    #     tb_writer.add_graph(torch.jit.trace(model, imgs, strict=False), [])  # add model graph
                elif plots and ni == 10 and wandb_logger.wandb:
                    wandb_logger.log({
                        "Mosaics": [
                            wandb_logger.wandb.Image(str(x), caption=x.name)
                            for x in save_dir.glob('train*.jpg') if x.exists()
                        ]
                    })

            # end batch ------------------------------------------------------------------------------------------------
        # end epoch ----------------------------------------------------------------------------------------------------

        # Scheduler
        lr = [x['lr'] for x in optimizer.param_groups]  # for tensorboard
        scheduler.step()

        # DDP process 0 or single-GPU
        if rank in [-1, 0]:
            # mAP
            ema.update_attr(model,
                            include=[
                                'yaml', 'nc', 'hyp', 'gr', 'names', 'stride',
                                'class_weights'
                            ])
            final_epoch = epoch + 1 == epochs
            if not opt.notest or final_epoch:  # Calculate mAP
                wandb_logger.current_epoch = epoch + 1
                results, maps, times = test.test(data_dict,
                                                 batch_size=batch_size * 2,
                                                 imgsz=imgsz_test,
                                                 model=ema.ema,
                                                 single_cls=opt.single_cls,
                                                 dataloader=testloader,
                                                 save_dir=save_dir,
                                                 verbose=nc < 50
                                                 and final_epoch,
                                                 plots=plots and final_epoch,
                                                 wandb_logger=wandb_logger,
                                                 compute_loss=compute_loss,
                                                 is_coco=is_coco)

            # Write
            with open(results_file, 'a') as f:
                f.write(s + '%10.4g' * 7 % results +
                        '\n')  # append metrics, val_loss
            if len(opt.name) and opt.bucket:
                os.system('gsutil cp %s gs://%s/results/results%s.txt' %
                          (results_file, opt.bucket, opt.name))

            # Log
            tags = [
                'train/box_loss',
                'train/obj_loss',
                'train/cls_loss',  # train loss
                'metrics/precision',
                'metrics/recall',
                'metrics/mAP_0.5',
                'metrics/mAP_0.5:0.95',
                'val/box_loss',
                'val/obj_loss',
                'val/cls_loss',  # val loss
                'x/lr0',
                'x/lr1',
                'x/lr2'
            ]  # params
            for x, tag in zip(list(mloss[:-1]) + list(results) + lr, tags):
                if tb_writer:
                    tb_writer.add_scalar(tag, x, epoch)  # tensorboard
                if wandb_logger.wandb:
                    wandb_logger.log({tag: x})  # W&B

            # Update best mAP
            fi = fitness(np.array(results).reshape(
                1, -1))  # weighted combination of [P, R, [email protected], [email protected]]
            if fi > best_fitness:
                best_fitness = fi
            wandb_logger.end_epoch(best_result=best_fitness == fi)

            # Save model
            if (not opt.nosave) or (final_epoch and not opt.evolve):  # if save
                ckpt = {
                    'epoch':
                    epoch,
                    'best_fitness':
                    best_fitness,
                    'training_results':
                    results_file.read_text(),
                    'model':
                    deepcopy(
                        model.module if is_parallel(model) else model).half(),
                    'ema':
                    deepcopy(ema.ema).half(),
                    'updates':
                    ema.updates,
                    'optimizer':
                    optimizer.state_dict(),
                    'wandb_id':
                    wandb_logger.wandb_run.id if wandb_logger.wandb else None
                }

                # Save last, best and delete
                torch.save(ckpt, last)
                if epoch % 20 == 0:

                    # epoch_c = wdir / '%d.pt'%epoch
                    torch.save(ckpt, epoch_c)
                if best_fitness == fi:
                    torch.save(ckpt, best)
                if wandb_logger.wandb:
                    if ((epoch + 1) % opt.save_period == 0
                            and not final_epoch) and opt.save_period != -1:
                        wandb_logger.log_model(last.parent,
                                               opt,
                                               epoch,
                                               fi,
                                               best_model=best_fitness == fi)
                del ckpt

        # end epoch ----------------------------------------------------------------------------------------------------
    # end training
    if rank in [-1, 0]:
        # Plots
        if plots:
            plot_results(save_dir=save_dir)  # save as results.png
            if wandb_logger.wandb:
                files = [
                    'results.png', 'confusion_matrix.png',
                    *[f'{x}_curve.png' for x in ('F1', 'PR', 'P', 'R')]
                ]
                wandb_logger.log({
                    "Results": [
                        wandb_logger.wandb.Image(str(save_dir / f), caption=f)
                        for f in files if (save_dir / f).exists()
                    ]
                })
        # Test best.pt
        logger.info('%g epochs completed in %.3f hours.\n' %
                    (epoch - start_epoch + 1, (time.time() - t0) / 3600))
        if opt.data.endswith('coco.yaml') and nc == 80:  # if COCO
            for m in (last,
                      best) if best.exists() else (last):  # speed, mAP tests
                results, _, _ = test.test(opt.data,
                                          batch_size=batch_size * 2,
                                          imgsz=imgsz_test,
                                          conf_thres=0.001,
                                          iou_thres=0.7,
                                          model=attempt_load(m, device).half(),
                                          single_cls=opt.single_cls,
                                          dataloader=testloader,
                                          save_dir=save_dir,
                                          save_json=True,
                                          plots=False,
                                          is_coco=is_coco)

        # Strip optimizers
        final = best if best.exists() else last  # final model
        for f in last, best:
            if f.exists():
                strip_optimizer(f)  # strip optimizers
        if opt.bucket:
            os.system(f'gsutil cp {final} gs://{opt.bucket}/weights')  # upload
        if wandb_logger.wandb and not opt.evolve:  # Log the stripped model
            wandb_logger.wandb.log_artifact(
                str(final),
                type='model',
                name='run_' + wandb_logger.wandb_run.id + '_model',
                aliases=['last', 'best', 'stripped'])
        wandb_logger.finish_run()
    else:
        dist.destroy_process_group()
    torch.cuda.empty_cache()
    return results
Exemple #2
0
def train(hyp, opt, device, tb_writer=None):
    logger.info(f'Hyperparameters {hyp}')
    log_dir = Path(tb_writer.log_dir) if tb_writer else Path(
        opt.logdir) / 'evolve'  # logging directory
    wdir = log_dir / 'weights'  # weights directory
    os.makedirs(wdir, exist_ok=True)
    last = wdir / 'last.pt'
    best = wdir / 'best.pt'
    results_file = str(log_dir / 'results.txt')
    epochs, batch_size, total_batch_size, weights, rank = \
        opt.epochs, opt.batch_size, opt.total_batch_size, opt.weights, opt.global_rank

    # Save run settings
    with open(log_dir / 'hyp.yaml', 'w') as f:
        yaml.dump(hyp, f, sort_keys=False)
    with open(log_dir / 'opt.yaml', 'w') as f:
        yaml.dump(vars(opt), f, sort_keys=False)

    # Configure
    cuda = device.type != 'cpu'
    init_seeds(2 + rank)
    with open(opt.data) as f:
        data_dict = yaml.load(f, Loader=yaml.FullLoader)  # data dict
    with torch_distributed_zero_first(rank):
        check_dataset(data_dict)  # check
    train_path = data_dict['train']
    test_path = data_dict['val']
    nc, names = (1, ['item']) if opt.single_cls else (int(
        data_dict['nc']), data_dict['names'])  # number classes, names
    assert len(names) == nc, '%g names found for nc=%g dataset in %s' % (
        len(names), nc, opt.data)  # check

    # Model
    pretrained = weights.endswith('.pt')
    if pretrained:
        with torch_distributed_zero_first(rank):
            attempt_download(weights)  # download if not found locally
        ckpt = torch.load(weights, map_location=device)  # load checkpoint
        if hyp.get('anchors'):
            ckpt['model'].yaml['anchors'] = round(
                hyp['anchors'])  # force autoanchor
        model = Model(opt.cfg or ckpt['model'].yaml, ch=3,
                      nc=nc).to(device)  # create
        exclude = ['anchor'] if opt.cfg or hyp.get('anchors') else [
        ]  # exclude keys
        state_dict = ckpt['model'].float().state_dict()  # to FP32
        state_dict = intersect_dicts(state_dict,
                                     model.state_dict(),
                                     exclude=exclude)  # intersect
        model.load_state_dict(state_dict, strict=False)  # load
        logger.info(
            'Transferred %g/%g items from %s' %
            (len(state_dict), len(model.state_dict()), weights))  # report
    else:
        model = Model(opt.cfg, ch=3, nc=nc).to(device)  # create

    # Freeze
    freeze = [
        '',
    ]  # parameter names to freeze (full or partial)
    if any(freeze):
        for k, v in model.named_parameters():
            if any(x in k for x in freeze):
                print('freezing %s' % k)
                v.requires_grad = False

    # Optimizer
    nbs = 64  # nominal batch size
    accumulate = max(round(nbs / total_batch_size),
                     1)  # accumulate loss before optimizing
    hyp['weight_decay'] *= total_batch_size * accumulate / nbs  # scale weight_decay

    pg0, pg1, pg2 = [], [], []  # optimizer parameter groups
    for k, v in model.named_parameters():
        v.requires_grad = True
        if '.bias' in k:
            pg2.append(v)  # biases
        elif '.weight' in k and '.bn' not in k:
            pg1.append(v)  # apply weight decay
        else:
            pg0.append(v)  # all else

    if opt.adam:
        optimizer = optim.Adam(pg0,
                               lr=hyp['lr0'],
                               betas=(hyp['momentum'],
                                      0.999))  # adjust beta1 to momentum
    else:
        optimizer = optim.SGD(pg0,
                              lr=hyp['lr0'],
                              momentum=hyp['momentum'],
                              nesterov=True)

    optimizer.add_param_group({
        'params': pg1,
        'weight_decay': hyp['weight_decay']
    })  # add pg1 with weight_decay
    optimizer.add_param_group({'params': pg2})  # add pg2 (biases)
    logger.info('Optimizer groups: %g .bias, %g conv.weight, %g other' %
                (len(pg2), len(pg1), len(pg0)))
    del pg0, pg1, pg2

    # Scheduler https://arxiv.org/pdf/1812.01187.pdf
    # https://pytorch.org/docs/stable/_modules/torch/optim/lr_scheduler.html#OneCycleLR
    lf = lambda x: ((1 + math.cos(x * math.pi / epochs)) / 2) * (1 - hyp[
        'lrf']) + hyp['lrf']  # cosine
    scheduler = lr_scheduler.LambdaLR(optimizer, lr_lambda=lf)
    # plot_lr_scheduler(optimizer, scheduler, epochs)

    # Resume
    start_epoch, best_fitness = 0, 0.0
    if pretrained:
        # Optimizer
        if ckpt['optimizer'] is not None:
            optimizer.load_state_dict(ckpt['optimizer'])
            best_fitness = ckpt['best_fitness']

        # Results
        if ckpt.get('training_results') is not None:
            with open(results_file, 'w') as file:
                file.write(ckpt['training_results'])  # write results.txt

        # Epochs
        start_epoch = ckpt['epoch'] + 1
        if opt.resume:
            assert start_epoch > 0, '%s training to %g epochs is finished, nothing to resume.' % (
                weights, epochs)
            shutil.copytree(wdir, wdir.parent /
                            f'weights_backup_epoch{start_epoch - 1}'
                            )  # save previous weights
        if epochs < start_epoch:
            logger.info(
                '%s has been trained for %g epochs. Fine-tuning for %g additional epochs.'
                % (weights, ckpt['epoch'], epochs))
            epochs += ckpt['epoch']  # finetune additional epochs

        del ckpt, state_dict

    # Image sizes
    gs = int(max(model.stride))  # grid size (max stride)
    imgsz, imgsz_test = [check_img_size(x, gs) for x in opt.img_size
                         ]  # verify imgsz are gs-multiples

    # DP mode
    if cuda and rank == -1 and torch.cuda.device_count() > 1:
        model = torch.nn.DataParallel(model)

    # SyncBatchNorm
    if opt.sync_bn and cuda and rank != -1:
        model = torch.nn.SyncBatchNorm.convert_sync_batchnorm(model).to(device)
        logger.info('Using SyncBatchNorm()')

    # Exponential moving average
    ema = ModelEMA(model) if rank in [-1, 0] else None

    # DDP mode
    if cuda and rank != -1:
        model = DDP(model,
                    device_ids=[opt.local_rank],
                    output_device=opt.local_rank)

    # Trainloader
    # print(f"hello::  {train_path}")
    dataloader, dataset = create_dataloader(train_path,
                                            imgsz,
                                            batch_size,
                                            gs,
                                            opt,
                                            hyp=hyp,
                                            augment=True,
                                            cache=opt.cache_images,
                                            rect=opt.rect,
                                            rank=rank,
                                            world_size=opt.world_size,
                                            workers=opt.workers)
    mlc = np.concatenate(dataset.labels, 0)[:, 0].max()  # max label class
    nb = len(dataloader)  # number of batches
    assert mlc < nc, 'Label class %g exceeds nc=%g in %s. Possible class labels are 0-%g' % (
        mlc, nc, opt.data, nc - 1)

    # Process 0
    if rank in [-1, 0]:
        ema.updates = start_epoch * nb // accumulate  # set EMA updates
        testloader = create_dataloader(test_path,
                                       imgsz_test,
                                       total_batch_size,
                                       gs,
                                       opt,
                                       hyp=hyp,
                                       augment=False,
                                       cache=opt.cache_images
                                       and not opt.notest,
                                       rect=True,
                                       rank=-1,
                                       world_size=opt.world_size,
                                       workers=opt.workers)[0]  # testloader

        if not opt.resume:
            labels = np.concatenate(dataset.labels, 0)
            c = torch.tensor(labels[:, 0])  # classes
            # cf = torch.bincount(c.long(), minlength=nc) + 1.  # frequency
            # model._initialize_biases(cf.to(device))
            plot_labels(labels, save_dir=log_dir)
            if tb_writer:
                # tb_writer.add_hparams(hyp, {})  # causes duplicate https://github.com/ultralytics/yolov5/pull/384
                tb_writer.add_histogram('classes', c, 0)

            # Anchors
            if not opt.noautoanchor:
                check_anchors(dataset,
                              model=model,
                              thr=hyp['anchor_t'],
                              imgsz=imgsz)

    # Model parameters
    hyp['cls'] *= nc / 80.  # scale coco-tuned hyp['cls'] to current dataset
    model.nc = nc  # attach number of classes to model
    model.hyp = hyp  # attach hyperparameters to model
    model.gr = 1.0  # giou loss ratio (obj_loss = 1.0 or giou)
    model.class_weights = labels_to_class_weights(dataset.labels, nc).to(
        device)  # attach class weights
    model.names = names

    # Start training
    t0 = time.time()
    nw = max(round(hyp['warmup_epochs'] * nb),
             1e3)  # number of warmup iterations, max(3 epochs, 1k iterations)
    # nw = min(nw, (epochs - start_epoch) / 2 * nb)  # limit warmup to < 1/2 of training
    maps = np.zeros(nc)  # mAP per class
    results = (
        0, 0, 0, 0, 0, 0, 0
    )  # 'P', 'R', 'mAP', 'F1', 'val GIoU', 'val Objectness', 'val Classification'
    scheduler.last_epoch = start_epoch - 1  # do not move
    scaler = amp.GradScaler(enabled=cuda)
    logger.info(
        'Image sizes %g train, %g test\nUsing %g dataloader workers\nLogging results to %s\n'
        'Starting training for %g epochs...' %
        (imgsz, imgsz_test, dataloader.num_workers, log_dir, epochs))
    for epoch in range(
            start_epoch, epochs
    ):  # epoch ------------------------------------------------------------------
        model.train()

        # Update image weights (optional)
        if opt.image_weights:
            # Generate indices
            if rank in [-1, 0]:
                cw = model.class_weights.cpu().numpy() * (
                    1 - maps)**2  # class weights
                iw = labels_to_image_weights(dataset.labels,
                                             nc=nc,
                                             class_weights=cw)  # image weights
                dataset.indices = random.choices(
                    range(dataset.n), weights=iw,
                    k=dataset.n)  # rand weighted idx
            # Broadcast if DDP
            if rank != -1:
                indices = (torch.tensor(dataset.indices)
                           if rank == 0 else torch.zeros(dataset.n)).int()
                dist.broadcast(indices, 0)
                if rank != 0:
                    dataset.indices = indices.cpu().numpy()

        # Update mosaic border
        # b = int(random.uniform(0.25 * imgsz, 0.75 * imgsz + gs) // gs * gs)
        # dataset.mosaic_border = [b - imgsz, -b]  # height, width borders

        mloss = torch.zeros(4, device=device)  # mean losses
        if rank != -1:
            dataloader.sampler.set_epoch(epoch)
        pbar = enumerate(dataloader)
        logger.info(
            ('\n' + '%10s' * 8) % ('Epoch', 'gpu_mem', 'GIoU', 'obj', 'cls',
                                   'total', 'targets', 'img_size'))
        if rank in [-1, 0]:
            pbar = tqdm(pbar, total=nb)  # progress bar
        optimizer.zero_grad()
        for i, (
                imgs, targets, paths, _
        ) in pbar:  # batch -------------------------------------------------------------
            ni = i + nb * epoch  # number integrated batches (since train start)
            imgs = imgs.to(device, non_blocking=True).float(
            ) / 255.0  # uint8 to float32, 0-255 to 0.0-1.0

            # Warmup
            if ni <= nw:
                xi = [0, nw]  # x interp
                # model.gr = np.interp(ni, xi, [0.0, 1.0])  # giou loss ratio (obj_loss = 1.0 or giou)
                accumulate = max(
                    1,
                    np.interp(ni, xi, [1, nbs / total_batch_size]).round())
                for j, x in enumerate(optimizer.param_groups):
                    # bias lr falls from 0.1 to lr0, all other lrs rise from 0.0 to lr0
                    x['lr'] = np.interp(ni, xi, [
                        hyp['warmup_bias_lr'] if j == 2 else 0.0,
                        x['initial_lr'] * lf(epoch)
                    ])
                    if 'momentum' in x:
                        x['momentum'] = np.interp(
                            ni, xi, [hyp['warmup_momentum'], hyp['momentum']])

            # Multi-scale
            if opt.multi_scale:
                sz = random.randrange(imgsz * 0.5,
                                      imgsz * 1.5 + gs) // gs * gs  # size
                sf = sz / max(imgs.shape[2:])  # scale factor
                if sf != 1:
                    ns = [math.ceil(x * sf / gs) * gs for x in imgs.shape[2:]
                          ]  # new shape (stretched to gs-multiple)
                    imgs = F.interpolate(imgs,
                                         size=ns,
                                         mode='bilinear',
                                         align_corners=False)

            # Forward
            with amp.autocast(enabled=cuda):
                pred = model(imgs)  # forward
                loss, loss_items = compute_loss(
                    pred, targets.to(device),
                    model)  # loss scaled by batch_size
                if rank != -1:
                    loss *= opt.world_size  # gradient averaged between devices in DDP mode

            # Backward
            scaler.scale(loss).backward()

            # Optimize
            if ni % accumulate == 0:
                scaler.step(optimizer)  # optimizer.step
                scaler.update()
                optimizer.zero_grad()
                if ema:
                    ema.update(model)

            # Print
            if rank in [-1, 0]:
                mloss = (mloss * i + loss_items) / (i + 1
                                                    )  # update mean losses
                mem = '%.3gG' % (torch.cuda.memory_reserved() / 1E9
                                 if torch.cuda.is_available() else 0)  # (GB)
                s = ('%10s' * 2 +
                     '%10.4g' * 6) % ('%g/%g' % (epoch, epochs - 1), mem,
                                      *mloss, targets.shape[0], imgs.shape[-1])
                pbar.set_description(s)

                # Plot
                if ni < 3:
                    f = str(log_dir / ('train_batch%g.jpg' % ni))  # filename
                    result = plot_images(images=imgs,
                                         targets=targets,
                                         paths=paths,
                                         fname=f)
                    if tb_writer and result is not None:
                        tb_writer.add_image(f,
                                            result,
                                            dataformats='HWC',
                                            global_step=epoch)
                        # tb_writer.add_graph(model, imgs)  # add model to tensorboard

            # end batch ------------------------------------------------------------------------------------------------

        # Scheduler
        lr = [x['lr'] for x in optimizer.param_groups]  # for tensorboard
        scheduler.step()

        # DDP process 0 or single-GPU
        if rank in [-1, 0]:
            # mAP
            if ema:
                ema.update_attr(
                    model,
                    include=['yaml', 'nc', 'hyp', 'gr', 'names', 'stride'])
            final_epoch = epoch + 1 == epochs
            if not opt.notest or final_epoch:  # Calculate mAP
                if final_epoch:  # replot predictions
                    [
                        os.remove(x) for x in glob.glob(
                            str(log_dir / 'test_batch*_pred.jpg'))
                        if os.path.exists(x)
                    ]
                results, maps, times = test.test(opt.data,
                                                 batch_size=total_batch_size,
                                                 imgsz=imgsz_test,
                                                 model=ema.ema,
                                                 single_cls=opt.single_cls,
                                                 dataloader=testloader,
                                                 save_dir=log_dir)

            # Write
            with open(results_file, 'a') as f:
                f.write(s + '%10.4g' * 7 % results +
                        '\n')  # P, R, mAP, F1, test_losses=(GIoU, obj, cls)
            if len(opt.name) and opt.bucket:
                os.system('gsutil cp %s gs://%s/results/results%s.txt' %
                          (results_file, opt.bucket, opt.name))

            # Tensorboard
            if tb_writer:
                tags = [
                    'train/giou_loss',
                    'train/obj_loss',
                    'train/cls_loss',  # train loss
                    'metrics/precision',
                    'metrics/recall',
                    'metrics/mAP_0.5',
                    'metrics/mAP_0.5:0.95',
                    'val/giou_loss',
                    'val/obj_loss',
                    'val/cls_loss',  # val loss
                    'x/lr0',
                    'x/lr1',
                    'x/lr2'
                ]  # params
                for x, tag in zip(list(mloss[:-1]) + list(results) + lr, tags):
                    tb_writer.add_scalar(tag, x, epoch)

            # Update best mAP
            fi = fitness(np.array(results).reshape(
                1, -1))  # fitness_i = weighted combination of [P, R, mAP, F1]
            if fi > best_fitness:
                best_fitness = fi

            # Save model
            save = (not opt.nosave) or (final_epoch and not opt.evolve)
            if save:
                with open(results_file, 'r') as f:  # create checkpoint
                    ckpt = {
                        'epoch':
                        epoch,
                        'best_fitness':
                        best_fitness,
                        'training_results':
                        f.read(),
                        'model':
                        ema.ema,
                        'optimizer':
                        None if final_epoch else optimizer.state_dict()
                    }

                # Save last, best and delete
                torch.save(ckpt, last)
                if best_fitness == fi:
                    torch.save(ckpt, best)
                del ckpt
        # end epoch ----------------------------------------------------------------------------------------------------
    # end training

    if rank in [-1, 0]:
        # Strip optimizers
        n = opt.name if opt.name.isnumeric() else ''
        fresults, flast, fbest = log_dir / f'results{n}.txt', wdir / f'last{n}.pt', wdir / f'best{n}.pt'
        for f1, f2 in zip([wdir / 'last.pt', wdir / 'best.pt', results_file],
                          [flast, fbest, fresults]):
            if os.path.exists(f1):
                os.rename(f1, f2)  # rename
                if str(f2).endswith('.pt'):  # is *.pt
                    strip_optimizer(f2)  # strip optimizer
                    os.system(
                        'gsutil cp %s gs://%s/weights' %
                        (f2, opt.bucket)) if opt.bucket else None  # upload
        # Finish
        if not opt.evolve:
            plot_results(save_dir=log_dir)  # save as results.png
        logger.info('%g epochs completed in %.3f hours.\n' %
                    (epoch - start_epoch + 1, (time.time() - t0) / 3600))

    dist.destroy_process_group() if rank not in [-1, 0] else None
    torch.cuda.empty_cache()
    return results
Exemple #3
0
def train(hyp, opt, device, tb_writer=None, wandb=None):
    logger.info(f'Hyperparameters {hyp}')
    save_dir, epochs, batch_size, total_batch_size, weights, rank = \
        Path(opt.save_dir), opt.epochs, opt.batch_size, opt.total_batch_size, opt.weights, opt.global_rank

    # Directories
    wdir = save_dir / 'weights'
    wdir.mkdir(parents=True, exist_ok=True)  # make dir
    last = wdir / 'last.pt'
    best = wdir / 'best.pt'
    results_file = save_dir / 'results.txt'

    # Save run settings
    with open(save_dir / 'hyp.yaml', 'w') as f:
        yaml.dump(hyp, f, sort_keys=False)
    with open(save_dir / 'opt.yaml', 'w') as f:
        yaml.dump(vars(opt), f, sort_keys=False)

    # Configure
    plots = not opt.evolve  # create plots
    cuda = device.type != 'cpu'
    init_seeds(2 + rank)
    with open(opt.data) as f:
        data_dict = yaml.load(f, Loader=yaml.FullLoader)  # data dict
    with torch_distributed_zero_first(rank):
        check_dataset(data_dict)  # check
    train_path = data_dict['train']
    test_path = data_dict['val']
    nc = 1 if opt.single_cls else int(data_dict['nc'])  # number of classes
    names = ['item'] if opt.single_cls and len(
        data_dict['names']) != 1 else data_dict['names']  # class names
    assert len(names) == nc, '%g names found for nc=%g dataset in %s' % (
        len(names), nc, opt.data)  # check

    # Model
    pretrained = weights.endswith('.pt')
    if pretrained:
        # with torch_distributed_zero_first(rank):
        #     attempt_download(weights)  # download if not found locally
        ckpt = torch.load(weights, map_location=device)  # load checkpoint
        if hyp.get('anchors'):
            ckpt['model'].yaml['anchors'] = round(
                hyp['anchors'])  # force autoanchor
        model = Model(opt.cfg or ckpt['model'].yaml, ch=3,
                      nc=nc).to(device)  # create
        exclude = ['anchor'] if opt.cfg or hyp.get('anchors') else [
        ]  # exclude keys
        state_dict = ckpt['model'].float().state_dict()  # to FP32
        state_dict = intersect_dicts(state_dict,
                                     model.state_dict(),
                                     exclude=exclude)  # intersect
        model.load_state_dict(state_dict, strict=False)  # load
        logger.info(
            'Transferred %g/%g items from %s' %
            (len(state_dict), len(model.state_dict()), weights))  # report
    else:
        model = Model(opt.cfg, ch=3, nc=nc).to(device)  # create

    # Freeze
    freeze = []  # parameter names to freeze (full or partial)
    for k, v in model.named_parameters():
        v.requires_grad = True  # train all layers
        if any(x in k for x in freeze):
            print('freezing %s' % k)
            v.requires_grad = False

    # Optimizer
    nbs = 64  # nominal batch size
    accumulate = max(round(nbs / total_batch_size),
                     1)  # accumulate loss before optimizing
    hyp['weight_decay'] *= total_batch_size * accumulate / nbs  # scale weight_decay
    logger.info(f"Scaled weight_decay = {hyp['weight_decay']}")

    pg0, pg1, pg2 = [], [], []  # optimizer parameter groups
    for k, v in model.named_modules():
        if hasattr(v, 'bias') and isinstance(v.bias, nn.Parameter):
            pg2.append(v.bias)  # biases
        if isinstance(v, nn.BatchNorm2d):
            pg0.append(v.weight)  # no decay
        elif hasattr(v, 'weight') and isinstance(v.weight, nn.Parameter):
            pg1.append(v.weight)  # apply decay

    if opt.adam:
        optimizer = optim.Adam(pg0,
                               lr=hyp['lr0'],
                               betas=(hyp['momentum'],
                                      0.999))  # adjust beta1 to momentum
    else:
        optimizer = optim.SGD(pg0,
                              lr=hyp['lr0'],
                              momentum=hyp['momentum'],
                              nesterov=True)

    optimizer.add_param_group({
        'params': pg1,
        'weight_decay': hyp['weight_decay']
    })  # add pg1 with weight_decay
    optimizer.add_param_group({'params': pg2})  # add pg2 (biases)
    logger.info('Optimizer groups: %g .bias, %g conv.weight, %g other' %
                (len(pg2), len(pg1), len(pg0)))
    del pg0, pg1, pg2

    # Scheduler https://arxiv.org/pdf/1812.01187.pdf
    # https://pytorch.org/docs/stable/_modules/torch/optim/lr_scheduler.html#OneCycleLR
    lf = one_cycle(1, hyp['lrf'], epochs)  # cosine 1->hyp['lrf']
    scheduler = lr_scheduler.LambdaLR(optimizer, lr_lambda=lf)
    # plot_lr_scheduler(optimizer, scheduler, epochs)

    # Logging
    if rank in [-1, 0] and wandb and wandb.run is None:
        opt.hyp = hyp  # add hyperparameters
        wandb_run = wandb.init(
            config=opt,
            resume="allow",
            project='YOLOv5'
            if opt.project == 'runs/train' else Path(opt.project).stem,
            name=save_dir.stem,
            id=ckpt.get('wandb_id') if 'ckpt' in locals() else None)
    loggers = {'wandb': wandb}  # loggers dict

    # Resume
    start_epoch, best_fitness = 0, 0.0
    if pretrained:
        # Optimizer
        if ckpt['optimizer'] is not None:
            optimizer.load_state_dict(ckpt['optimizer'])
            best_fitness = ckpt['best_fitness']

        # Results
        if ckpt.get('training_results') is not None:
            with open(results_file, 'w') as file:
                file.write(ckpt['training_results'])  # write results.txt

        # Epochs
        start_epoch = ckpt['epoch'] + 1
        if opt.resume:
            assert start_epoch > 0, '%s training to %g epochs is finished, nothing to resume.' % (
                weights, epochs)
        if epochs < start_epoch:
            logger.info(
                '%s has been trained for %g epochs. Fine-tuning for %g additional epochs.'
                % (weights, ckpt['epoch'], epochs))
            epochs += ckpt['epoch']  # finetune additional epochs

        del ckpt, state_dict

    # Image sizes
    gs = int(model.stride.max())  # grid size (max stride)
    nl = model.model[
        -1].nl  # number of detection layers (used for scaling hyp['obj'])
    imgsz, imgsz_test = [check_img_size(x, gs) for x in opt.img_size
                         ]  # verify imgsz are gs-multiples

    # TODO 将cfg添加到配置变量中
    cfg_model = Darknet('cfg/yolov5s_v4.cfg',
                        (opt.img_size[0], opt.img_size[0])).to(device)
    # cfg_model = Darknet('cfg/yolov5s_v3.cfg', (416, 416)).to(device)
    copy_weight_v4(model, cfg_model)
    # 剪枝操作  sr开启稀疏训练  prune 不同的剪枝策略
    # 剪枝操作
    if opt.prune == 1:
        CBL_idx, _, prune_idx, shortcut_idx, _ = parse_module_defs2(
            cfg_model.module_defs)
        if opt.sr:
            print('shortcut sparse training')
    elif opt.prune == 0:
        CBL_idx, _, prune_idx = parse_module_defs(cfg_model.module_defs)
        if opt.sr:
            print('normal sparse training ')

    # DP mode
    if cuda and rank == -1 and torch.cuda.device_count() > 1:
        model = torch.nn.DataParallel(model)

    # SyncBatchNorm
    if opt.sync_bn and cuda and rank != -1:
        model = torch.nn.SyncBatchNorm.convert_sync_batchnorm(model).to(device)
        logger.info('Using SyncBatchNorm()')

    # EMA
    ema = ModelEMA(model) if rank in [-1, 0] else None

    # DDP mode
    if cuda and rank != -1:
        model = DDP(model,
                    device_ids=[opt.local_rank],
                    output_device=opt.local_rank)

    # Trainloader
    dataloader, dataset = create_dataloader(train_path,
                                            imgsz,
                                            batch_size,
                                            gs,
                                            opt,
                                            hyp=hyp,
                                            augment=True,
                                            cache=opt.cache_images,
                                            rect=opt.rect,
                                            rank=rank,
                                            world_size=opt.world_size,
                                            workers=opt.workers,
                                            image_weights=opt.image_weights,
                                            quad=opt.quad)
    mlc = np.concatenate(dataset.labels, 0)[:, 0].max()  # max label class
    nb = len(dataloader)  # number of batches
    assert mlc < nc, 'Label class %g exceeds nc=%g in %s. Possible class labels are 0-%g' % (
        mlc, nc, opt.data, nc - 1)

    # Process 0
    if rank in [-1, 0]:
        ema.updates = start_epoch * nb // accumulate  # set EMA updates
        testloader = create_dataloader(
            test_path,
            imgsz_test,
            total_batch_size,
            gs,
            opt,  # testloader
            hyp=hyp,
            cache=opt.cache_images and not opt.notest,
            rect=True,
            rank=-1,
            world_size=opt.world_size,
            workers=opt.workers,
            pad=0.5)[0]

        if not opt.resume:
            labels = np.concatenate(dataset.labels, 0)
            c = torch.tensor(labels[:, 0])  # classes
            # cf = torch.bincount(c.long(), minlength=nc) + 1.  # frequency
            # model._initialize_biases(cf.to(device))
            if plots:
                plot_labels(labels, save_dir, loggers)
                if tb_writer:
                    tb_writer.add_histogram('classes', c, 0)

            # Anchors
            if not opt.noautoanchor:
                check_anchors(dataset,
                              model=model,
                              thr=hyp['anchor_t'],
                              imgsz=imgsz)

    # Model parameters
    hyp['cls'] *= nc / 80.  # scale hyp['cls'] to class count
    hyp['obj'] *= imgsz**2 / 640.**2 * 3. / nl  # scale hyp['obj'] to image size and output layers
    model.nc = nc  # attach number of classes to model
    model.hyp = hyp  # attach hyperparameters to model
    model.gr = 1.0  # iou loss ratio (obj_loss = 1.0 or iou)
    model.class_weights = labels_to_class_weights(
        dataset.labels, nc).to(device) * nc  # attach class weights
    model.names = names

    for idx in prune_idx:
        bn_weights = gather_bn_weights(cfg_model.module_list, [idx])
        tb_writer.add_histogram('before_train_perlayer_bn_weights/hist',
                                bn_weights.numpy(),
                                idx,
                                bins='doane')

    # Start training
    t0 = time.time()
    nw = max(round(hyp['warmup_epochs'] * nb),
             1000)  # number of warmup iterations, max(3 epochs, 1k iterations)
    # nw = min(nw, (epochs - start_epoch) / 2 * nb)  # limit warmup to < 1/2 of training
    maps = np.zeros(nc)  # mAP per class
    results = (0, 0, 0, 0, 0, 0, 0
               )  # P, R, [email protected], [email protected], val_loss(box, obj, cls)
    scheduler.last_epoch = start_epoch - 1  # do not move
    scaler = amp.GradScaler(enabled=cuda)
    logger.info('Image sizes %g train, %g test\n'
                'Using %g dataloader workers\nLogging results to %s\n'
                'Starting training for %g epochs...' %
                (imgsz, imgsz_test, dataloader.num_workers, save_dir, epochs))
    for epoch in range(
            start_epoch, epochs
    ):  # epoch ------------------------------------------------------------------
        model.train()

        # Update image weights (optional)
        if opt.image_weights:
            # Generate indices
            if rank in [-1, 0]:
                cw = model.class_weights.cpu().numpy() * (
                    1 - maps)**2 / nc  # class weights
                iw = labels_to_image_weights(dataset.labels,
                                             nc=nc,
                                             class_weights=cw)  # image weights
                dataset.indices = random.choices(
                    range(dataset.n), weights=iw,
                    k=dataset.n)  # rand weighted idx
            # Broadcast if DDP
            if rank != -1:
                indices = (torch.tensor(dataset.indices)
                           if rank == 0 else torch.zeros(dataset.n)).int()
                dist.broadcast(indices, 0)
                if rank != 0:
                    dataset.indices = indices.cpu().numpy()

        # Update mosaic border
        # b = int(random.uniform(0.25 * imgsz, 0.75 * imgsz + gs) // gs * gs)
        # dataset.mosaic_border = [b - imgsz, -b]  # height, width borders

        mloss = torch.zeros(4, device=device)  # mean losses
        if rank != -1:
            dataloader.sampler.set_epoch(epoch)
        pbar = enumerate(dataloader)
        logger.info(
            ('\n' + '%10s' * 8) % ('Epoch', 'gpu_mem', 'box', 'obj', 'cls',
                                   'total', 'targets', 'img_size'))
        if rank in [-1, 0]:
            pbar = tqdm(pbar, total=nb)  # progress bar
        optimizer.zero_grad()
        sr_flag = get_sr_flag(epoch, opt.sr)
        for i, (
                imgs, targets, paths, _
        ) in pbar:  # batch -------------------------------------------------------------
            ni = i + nb * epoch  # number integrated batches (since train start)
            imgs = imgs.to(device, non_blocking=True).float(
            ) / 255.0  # uint8 to float32, 0-255 to 0.0-1.0

            # Warmup
            if ni <= nw:
                xi = [0, nw]  # x interp
                # model.gr = np.interp(ni, xi, [0.0, 1.0])  # iou loss ratio (obj_loss = 1.0 or iou)
                accumulate = max(
                    1,
                    np.interp(ni, xi, [1, nbs / total_batch_size]).round())
                for j, x in enumerate(optimizer.param_groups):
                    # bias lr falls from 0.1 to lr0, all other lrs rise from 0.0 to lr0
                    x['lr'] = np.interp(ni, xi, [
                        hyp['warmup_bias_lr'] if j == 2 else 0.0,
                        x['initial_lr'] * lf(epoch)
                    ])
                    if 'momentum' in x:
                        x['momentum'] = np.interp(
                            ni, xi, [hyp['warmup_momentum'], hyp['momentum']])

            # Multi-scale
            if opt.multi_scale:
                sz = random.randrange(imgsz * 0.5,
                                      imgsz * 1.5 + gs) // gs * gs  # size
                sf = sz / max(imgs.shape[2:])  # scale factor
                if sf != 1:
                    ns = [math.ceil(x * sf / gs) * gs for x in imgs.shape[2:]
                          ]  # new shape (stretched to gs-multiple)
                    imgs = F.interpolate(imgs,
                                         size=ns,
                                         mode='bilinear',
                                         align_corners=False)

            # Forward
            # with amp.autocast(enabled=cuda):
            #     pred = model(imgs)  # forward
            #     loss, loss_items = compute_loss(pred, targets.to(device), model)  # loss scaled by batch_size
            #     if rank != -1:
            #         loss *= opt.world_size  # gradient averaged between devices in DDP mode
            #     if opt.quad:
            #         loss *= 4.

            # Forward
            pred = model(imgs)
            # Loss
            loss, loss_items = compute_loss(pred, targets.to(device),
                                            model)  # scaled by batch_size
            if rank != -1:
                loss *= opt.world_size  # gradient averaged between devices in DDP mode
            if not torch.isfinite(loss):
                print('WARNING: non-finite loss, ending training ', loss_items)
                return results
            # Backward
            # scaler.scale(loss).backward()
            loss.backward()

            idx2mask = None
            # if opt.sr and opt.prune==1 and epoch > opt.epochs * 0.5:
            #     idx2mask = get_mask2(model, prune_idx, 0.85)
            # copy_weight(model,cfg_model)
            BNOptimizer.updateBN(sr_flag, cfg_model.module_list, opt.s,
                                 prune_idx, epoch, idx2mask, opt)

            # Optimize
            if ni % accumulate == 0:
                # scaler.step(optimizer)  # optimizer.step
                # scaler.update()
                optimizer.step()
                optimizer.zero_grad()
                if ema:
                    ema.update(model)

            # Print
            if rank in [-1, 0]:
                mloss = (mloss * i + loss_items) / (i + 1
                                                    )  # update mean losses
                mem = '%.3gG' % (torch.cuda.memory_reserved() / 1E9
                                 if torch.cuda.is_available() else 0)  # (GB)
                s = ('%10s' * 2 +
                     '%10.4g' * 6) % ('%g/%g' % (epoch, epochs - 1), mem,
                                      *mloss, targets.shape[0], imgs.shape[-1])
                pbar.set_description(s)

                # Plot
                if plots and ni < 3:
                    f = save_dir / f'train_batch{ni}.jpg'  # filename
                    Thread(target=plot_images,
                           args=(imgs, targets, paths, f),
                           daemon=True).start()
                    # if tb_writer:
                    #     tb_writer.add_image(f, result, dataformats='HWC', global_step=epoch)
                    #     tb_writer.add_graph(model, imgs)  # add model to tensorboard
                elif plots and ni == 3 and wandb:
                    wandb.log({
                        "Mosaics": [
                            wandb.Image(str(x), caption=x.name)
                            for x in save_dir.glob('train*.jpg')
                        ]
                    })

            # end batch ------------------------------------------------------------------------------------------------
        # end epoch ----------------------------------------------------------------------------------------------------

        # Scheduler
        lr = [x['lr'] for x in optimizer.param_groups]  # for tensorboard
        scheduler.step()

        # DDP process 0 or single-GPU
        if rank in [-1, 0]:
            # mAP
            if ema:
                ema.update_attr(model,
                                include=[
                                    'yaml', 'nc', 'hyp', 'gr', 'names',
                                    'stride', 'class_weights'
                                ])
            final_epoch = epoch + 1 == epochs
            if not opt.notest or final_epoch:  # Calculate mAP
                results, maps, times = test.test(
                    opt.data,
                    batch_size=total_batch_size,
                    imgsz=imgsz_test,
                    model=ema.ema,
                    single_cls=opt.single_cls,
                    dataloader=testloader,
                    save_dir=save_dir,
                    plots=plots and final_epoch,
                    log_imgs=opt.log_imgs if wandb else 0)

            # Write
            with open(results_file, 'a') as f:
                f.write(
                    s + '%10.4g' * 7 % results +
                    '\n')  # P, R, [email protected], [email protected], val_loss(box, obj, cls)
            if len(opt.name) and opt.bucket:
                os.system('gsutil cp %s gs://%s/results/results%s.txt' %
                          (results_file, opt.bucket, opt.name))

            # Log
            tags = [
                'train/box_loss',
                'train/obj_loss',
                'train/cls_loss',  # train loss
                'metrics/precision',
                'metrics/recall',
                'metrics/mAP_0.5',
                'metrics/mAP_0.5:0.95',
                'val/box_loss',
                'val/obj_loss',
                'val/cls_loss',  # val loss
                'x/lr0',
                'x/lr1',
                'x/lr2'
            ]  # params
            for x, tag in zip(list(mloss[:-1]) + list(results) + lr, tags):
                if tb_writer:
                    tb_writer.add_scalar(tag, x, epoch)  # tensorboard

                if wandb:
                    wandb.log({tag: x})  # W&B
            #剪枝后bn层权重
            bn_weights = gather_bn_weights(cfg_model.module_list, prune_idx)
            tb_writer.add_histogram('bn_weights/hist',
                                    bn_weights.numpy(),
                                    epoch,
                                    bins='doane')

            # Update best mAP
            fi = fitness(np.array(results).reshape(
                1, -1))  # weighted combination of [P, R, [email protected], [email protected]]
            if fi > best_fitness:
                best_fitness = fi

            # Save model
            save = (not opt.nosave) or (final_epoch and not opt.evolve)
            if save:
                with open(results_file, 'r') as f:  # create checkpoint
                    ckpt = {
                        'epoch':
                        epoch,
                        'best_fitness':
                        best_fitness,
                        'training_results':
                        f.read(),
                        'model':
                        ema.ema,
                        'optimizer':
                        None if final_epoch else optimizer.state_dict(),
                        'wandb_id':
                        wandb_run.id if wandb else None
                    }

                # Save last, best and delete
                torch.save(ckpt, last)
                if best_fitness == fi:
                    torch.save(ckpt, best)
                del ckpt
        # end epoch ----------------------------------------------------------------------------------------------------
    # end training
    for idx in prune_idx:
        bn_weights = gather_bn_weights(model.module_list, [idx])
        tb_writer.add_histogram('after_train_perlayer_bn_weights/hist',
                                bn_weights.numpy(),
                                idx,
                                bins='doane')

    if rank in [-1, 0]:
        # Strip optimizers
        final = best if best.exists() else last  # final model
        for f in [last, best]:
            if f.exists():
                strip_optimizer(f)  # strip optimizers
        if opt.bucket:
            os.system(f'gsutil cp {final} gs://{opt.bucket}/weights')  # upload

        # Plots
        if plots:
            plot_results(save_dir=save_dir)  # save as results.png
            if wandb:
                files = [
                    'results.png', 'precision_recall_curve.png',
                    'confusion_matrix.png'
                ]
                wandb.log({
                    "Results": [
                        wandb.Image(str(save_dir / f), caption=f)
                        for f in files if (save_dir / f).exists()
                    ]
                })
                if opt.log_artifacts:
                    wandb.log_artifact(artifact_or_path=str(final),
                                       type='model',
                                       name=save_dir.stem)

        # Test best.pt
        logger.info('%g epochs completed in %.3f hours.\n' %
                    (epoch - start_epoch + 1, (time.time() - t0) / 3600))
        if opt.data.endswith('coco.yaml') and nc == 80:  # if COCO
            for conf, iou, save_json in ([0.25, 0.45,
                                          False], [0.001, 0.65,
                                                   True]):  # speed, mAP tests
                results, _, _ = test.test(opt.data,
                                          batch_size=total_batch_size,
                                          imgsz=imgsz_test,
                                          conf_thres=conf,
                                          iou_thres=iou,
                                          model=attempt_load(final,
                                                             device).half(),
                                          single_cls=opt.single_cls,
                                          dataloader=testloader,
                                          save_dir=save_dir,
                                          save_json=save_json,
                                          plots=False)

    else:
        dist.destroy_process_group()

    wandb.run.finish() if wandb and wandb.run else None
    torch.cuda.empty_cache()
    return results
def train(hyp, opt, device, tb_writer=None, wandb=None):
    logger.info(
        colorstr("hyperparameters: ") + ", ".join(f"{k}={v}"
                                                  for k, v in hyp.items()))
    save_dir, epochs, batch_size, total_batch_size, weights, rank = (
        Path(opt.save_dir),
        opt.epochs,
        opt.batch_size,
        opt.total_batch_size,
        opt.weights,
        opt.global_rank,
    )

    # Directories
    wdir = save_dir / "weights"
    wdir.mkdir(parents=True, exist_ok=True)  # make dir
    last = wdir / "last.pt"
    best = wdir / "best.pt"
    results_file = save_dir / "results.txt"

    # Save run settings
    with open(save_dir / "hyp.yaml", "w") as f:
        yaml.dump(hyp, f, sort_keys=False)
    with open(save_dir / "opt.yaml", "w") as f:
        # yaml.dump(vars(opt), f, sort_keys=False)  # opt 実行パラメータ
        yaml.dump(str(opt), f, sort_keys=False)

    # Configure
    plots = not opt.evolve  # create plots
    cuda = device.type != "cpu"
    init_seeds(2 + rank)
    with open(opt.data) as f:
        data_dict = yaml.load(f, Loader=yaml.SafeLoader)  # data dict
    with torch_distributed_zero_first(rank):
        check_dataset(data_dict)  # check
    train_path = data_dict["train"]
    test_path = data_dict["val"]
    nc = 1 if opt.single_cls else int(data_dict["nc"])  # number of classes
    names = (["item"] if opt.single_cls and len(data_dict["names"]) != 1 else
             data_dict["names"])  # class names
    assert len(names) == nc, "%g names found for nc=%g dataset in %s" % (
        len(names),
        nc,
        opt.data,
    )  # check

    # Model
    pretrained = weights.endswith(".pt")
    if pretrained:
        with torch_distributed_zero_first(rank):
            attempt_download(weights)  # download if not found locally
        ckpt = torch.load(weights, map_location=device)  # load checkpoint
        if hyp.get("anchors"):
            ckpt["model"].yaml["anchors"] = round(
                hyp["anchors"])  # force autoanchor
        model = Model(opt.cfg or ckpt["model"].yaml, ch=3,
                      nc=nc).to(device)  # create
        exclude = ["anchor"] if opt.cfg or hyp.get("anchors") else [
        ]  # exclude keys
        state_dict = ckpt["model"].float().state_dict()  # to FP32
        state_dict = intersect_dicts(state_dict,
                                     model.state_dict(),
                                     exclude=exclude)  # intersect
        model.load_state_dict(state_dict, strict=False)  # load
        logger.info(
            "Transferred %g/%g items from %s" %
            (len(state_dict), len(model.state_dict()), weights))  # report
    else:
        model = Model(opt.cfg, ch=3, nc=nc).to(device)  # create

    # Freeze
    freeze = []  # parameter names to freeze (full or partial)
    for k, v in model.named_parameters():
        v.requires_grad = True  # train all layers
        if any(x in k for x in freeze):
            print("freezing %s" % k)
            v.requires_grad = False

    # Optimizer
    nbs = 64  # nominal batch size
    accumulate = max(round(nbs / total_batch_size),
                     1)  # accumulate loss before optimizing
    hyp["weight_decay"] *= total_batch_size * accumulate / nbs  # scale weight_decay
    logger.info(f"Scaled weight_decay = {hyp['weight_decay']}")

    pg0, pg1, pg2 = [], [], []  # optimizer parameter groups
    for k, v in model.named_modules():
        if hasattr(v, "bias") and isinstance(v.bias, nn.Parameter):
            pg2.append(v.bias)  # biases
        if isinstance(v, nn.BatchNorm2d):
            pg0.append(v.weight)  # no decay
        elif hasattr(v, "weight") and isinstance(v.weight, nn.Parameter):
            pg1.append(v.weight)  # apply decay

    if opt.adam:
        optimizer = optim.Adam(pg0,
                               lr=hyp["lr0"],
                               betas=(hyp["momentum"],
                                      0.999))  # adjust beta1 to momentum
    else:
        optimizer = optim.SGD(pg0,
                              lr=hyp["lr0"],
                              momentum=hyp["momentum"],
                              nesterov=True)

    optimizer.add_param_group({
        "params": pg1,
        "weight_decay": hyp["weight_decay"]
    })  # add pg1 with weight_decay
    optimizer.add_param_group({"params": pg2})  # add pg2 (biases)
    logger.info("Optimizer groups: %g .bias, %g conv.weight, %g other" %
                (len(pg2), len(pg1), len(pg0)))
    del pg0, pg1, pg2

    # Scheduler https://arxiv.org/pdf/1812.01187.pdf
    # https://pytorch.org/docs/stable/_modules/torch/optim/lr_scheduler.html#OneCycleLR
    if opt.linear_lr:
        lf = (lambda x: (1 - x / (epochs - 1)) *
              (1.0 - hyp["lrf"]) + hyp["lrf"])  # linear
    else:
        lf = one_cycle(1, hyp["lrf"], epochs)  # cosine 1->hyp['lrf']
    scheduler = lr_scheduler.LambdaLR(optimizer, lr_lambda=lf)
    # plot_lr_scheduler(optimizer, scheduler, epochs)

    # Logging
    if rank in [-1, 0] and wandb and wandb.run is None:
        opt.hyp = hyp  # add hyperparameters
        wandb_run = wandb.init(
            config=opt,
            resume="allow",
            project="YOLOv5"
            if opt.project == "runs/train" else Path(opt.project).stem,
            name=save_dir.stem,
            id=ckpt.get("wandb_id") if "ckpt" in locals() else None,
        )
    loggers = {"wandb": wandb}  # loggers dict

    # Resume
    start_epoch, best_fitness = 0, 0.0
    if pretrained:
        # Optimizer
        if ckpt["optimizer"] is not None:
            optimizer.load_state_dict(ckpt["optimizer"])
            best_fitness = ckpt["best_fitness"]

        # Results
        if ckpt.get("training_results") is not None:
            with open(results_file, "w") as file:
                file.write(ckpt["training_results"])  # write results.txt

        # Epochs
        start_epoch = ckpt["epoch"] + 1
        if opt.resume:
            assert (
                start_epoch > 0
            ), "%s training to %g epochs is finished, nothing to resume." % (
                weights,
                epochs,
            )
        if epochs < start_epoch:
            logger.info(
                "%s has been trained for %g epochs. Fine-tuning for %g additional epochs."
                % (weights, ckpt["epoch"], epochs))
            epochs += ckpt["epoch"]  # finetune additional epochs

        del ckpt, state_dict

    # Image sizes
    gs = int(model.stride.max())  # grid size (max stride)
    nl = model.model[
        -1].nl  # number of detection layers (used for scaling hyp['obj'])
    imgsz, imgsz_test = [check_img_size(x, gs) for x in opt.img_size
                         ]  # verify imgsz are gs-multiples

    # DP mode
    if cuda and rank == -1 and torch.cuda.device_count() > 1:
        model = torch.nn.DataParallel(model)

    # SyncBatchNorm
    if opt.sync_bn and cuda and rank != -1:
        model = torch.nn.SyncBatchNorm.convert_sync_batchnorm(model).to(device)
        logger.info("Using SyncBatchNorm()")

    # EMA
    ema = ModelEMA(model) if rank in [-1, 0] else None

    # DDP mode
    if cuda and rank != -1:
        model = DDP(model,
                    device_ids=[opt.local_rank],
                    output_device=opt.local_rank)

    # Trainloader
    dataloader, dataset = create_dataloader(
        train_path,
        imgsz,
        batch_size,
        gs,
        opt,
        hyp=hyp,
        augment=True,
        cache=opt.cache_images,
        rect=opt.rect,
        rank=rank,
        world_size=opt.world_size,
        workers=opt.workers,
        image_weights=opt.image_weights,
        quad=opt.quad,
        prefix=colorstr("train: "),
    )
    mlc = np.concatenate(dataset.labels, 0)[:, 0].max()  # max label class
    nb = len(dataloader)  # number of batches
    assert (
        mlc < nc
    ), "Label class %g exceeds nc=%g in %s. Possible class labels are 0-%g" % (
        mlc,
        nc,
        opt.data,
        nc - 1,
    )

    # Process 0
    if rank in [-1, 0]:
        ema.updates = start_epoch * nb // accumulate  # set EMA updates
        testloader = create_dataloader(
            test_path,
            imgsz_test,
            batch_size * 2,
            gs,
            opt,  # testloader
            hyp=hyp,
            cache=opt.cache_images and not opt.notest,
            rect=True,
            rank=-1,
            world_size=opt.world_size,
            workers=opt.workers,
            pad=0.5,
            prefix=colorstr("val: "),
        )[0]

        if not opt.resume:
            labels = np.concatenate(dataset.labels, 0)
            c = torch.tensor(labels[:, 0])  # classes
            # cf = torch.bincount(c.long(), minlength=nc) + 1.  # frequency
            # model._initialize_biases(cf.to(device))
            if plots:
                plot_labels(labels, save_dir, loggers)
                if tb_writer:
                    tb_writer.add_histogram("classes", c, 0)

            # Anchors
            if not opt.noautoanchor:
                check_anchors(dataset,
                              model=model,
                              thr=hyp["anchor_t"],
                              imgsz=imgsz)

    # Model parameters
    hyp["box"] *= 3.0 / nl  # scale to layers
    hyp["cls"] *= nc / 80.0 * 3.0 / nl  # scale to classes and layers
    hyp["obj"] *= (imgsz / 640)**2 * 3.0 / nl  # scale to image size and layers
    model.nc = nc  # attach number of classes to model
    model.hyp = hyp  # attach hyperparameters to model
    model.gr = 1.0  # iou loss ratio (obj_loss = 1.0 or iou)
    model.class_weights = (
        labels_to_class_weights(dataset.labels, nc).to(device) * nc
    )  # attach class weights
    model.names = names

    # Start training
    t0 = time.time()
    nw = max(round(hyp["warmup_epochs"] * nb),
             1000)  # number of warmup iterations, max(3 epochs, 1k iterations)
    # nw = min(nw, (epochs - start_epoch) / 2 * nb)  # limit warmup to < 1/2 of training
    maps = np.zeros(nc)  # mAP per class
    results = (0, 0, 0, 0, 0, 0, 0
               )  # P, R, [email protected], [email protected], val_loss(box, obj, cls)
    scheduler.last_epoch = start_epoch - 1  # do not move
    scaler = amp.GradScaler(enabled=cuda)
    compute_loss = ComputeLoss(model)  # init loss class
    logger.info(f"Image sizes {imgsz} train, {imgsz_test} test\n"
                f"Using {dataloader.num_workers} dataloader workers\n"
                f"Logging results to {save_dir}\n"
                f"Starting training for {epochs} epochs...")
    for epoch in range(
            start_epoch, epochs
    ):  # epoch ------------------------------------------------------------------
        model.train()

        # Update image weights (optional)
        if opt.image_weights:
            # Generate indices
            if rank in [-1, 0]:
                cw = (model.class_weights.cpu().numpy() * (1 - maps)**2 / nc
                      )  # class weights
                iw = labels_to_image_weights(dataset.labels,
                                             nc=nc,
                                             class_weights=cw)  # image weights
                dataset.indices = random.choices(
                    range(dataset.n), weights=iw,
                    k=dataset.n)  # rand weighted idx
            # Broadcast if DDP
            if rank != -1:
                indices = (torch.tensor(dataset.indices)
                           if rank == 0 else torch.zeros(dataset.n)).int()
                dist.broadcast(indices, 0)
                if rank != 0:
                    dataset.indices = indices.cpu().numpy()

        # Update mosaic border
        # b = int(random.uniform(0.25 * imgsz, 0.75 * imgsz + gs) // gs * gs)
        # dataset.mosaic_border = [b - imgsz, -b]  # height, width borders

        mloss = torch.zeros(4, device=device)  # mean losses
        if rank != -1:
            dataloader.sampler.set_epoch(epoch)
        pbar = enumerate(dataloader)
        logger.info(
            ("\n" + "%10s" * 8) % ("Epoch", "gpu_mem", "box", "obj", "cls",
                                   "total", "targets", "img_size"))
        if rank in [-1, 0]:
            pbar = tqdm(pbar, total=nb)  # progress bar
        optimizer.zero_grad()
        for i, (
                imgs,
                targets,
                paths,
                _,
        ) in (
                pbar
        ):  # batch -------------------------------------------------------------
            ni = i + nb * epoch  # number integrated batches (since train start)
            imgs = (imgs.to(device, non_blocking=True).float() / 255.0
                    )  # uint8 to float32, 0-255 to 0.0-1.0

            # Warmup
            if ni <= nw:
                xi = [0, nw]  # x interp
                # model.gr = np.interp(ni, xi, [0.0, 1.0])  # iou loss ratio (obj_loss = 1.0 or iou)
                accumulate = max(
                    1,
                    np.interp(ni, xi, [1, nbs / total_batch_size]).round())
                for j, x in enumerate(optimizer.param_groups):
                    # bias lr falls from 0.1 to lr0, all other lrs rise from 0.0 to lr0
                    x["lr"] = np.interp(
                        ni,
                        xi,
                        [
                            hyp["warmup_bias_lr"] if j == 2 else 0.0,
                            x["initial_lr"] * lf(epoch),
                        ],
                    )
                    if "momentum" in x:
                        x["momentum"] = np.interp(
                            ni, xi, [hyp["warmup_momentum"], hyp["momentum"]])

            # Multi-scale
            if opt.multi_scale:
                sz = random.randrange(imgsz * 0.5,
                                      imgsz * 1.5 + gs) // gs * gs  # size
                sf = sz / max(imgs.shape[2:])  # scale factor
                if sf != 1:
                    ns = [math.ceil(x * sf / gs) * gs for x in imgs.shape[2:]
                          ]  # new shape (stretched to gs-multiple)
                    imgs = F.interpolate(imgs,
                                         size=ns,
                                         mode="bilinear",
                                         align_corners=False)

            # Forward
            with amp.autocast(enabled=cuda):
                pred = model(imgs)  # forward
                loss, loss_items = compute_loss(
                    pred, targets.to(device))  # loss scaled by batch_size
                if rank != -1:
                    loss *= (opt.world_size
                             )  # gradient averaged between devices in DDP mode
                if opt.quad:
                    loss *= 4.0

            # Backward
            scaler.scale(loss).backward()

            # Optimize
            if ni % accumulate == 0:
                scaler.step(optimizer)  # optimizer.step
                scaler.update()
                optimizer.zero_grad()
                if ema:
                    ema.update(model)

            # Print
            if rank in [-1, 0]:
                mloss = (mloss * i + loss_items) / (i + 1
                                                    )  # update mean losses
                mem = "%.3gG" % (torch.cuda.memory_reserved() / 1e9
                                 if torch.cuda.is_available() else 0)  # (GB)
                s = ("%10s" * 2 + "%10.4g" * 6) % (
                    "%g/%g" % (epoch, epochs - 1),
                    mem,
                    *mloss,
                    targets.shape[0],
                    imgs.shape[-1],
                )
                pbar.set_description(s)

                # Plot
                if plots and ni < 3:
                    f = save_dir / f"train_batch{ni}.jpg"  # filename
                    Thread(target=plot_images,
                           args=(imgs, targets, paths, f),
                           daemon=True).start()
                    # if tb_writer:
                    #     tb_writer.add_image(f, result, dataformats='HWC', global_step=epoch)
                    #     tb_writer.add_graph(model, imgs)  # add model to tensorboard
                elif plots and ni == 10 and wandb:
                    wandb.log(
                        {
                            "Mosaics": [
                                wandb.Image(str(x), caption=x.name)
                                for x in save_dir.glob("train*.jpg")
                                if x.exists()
                            ]
                        },
                        commit=False,
                    )

            # end batch ------------------------------------------------------------------------------------------------
        # end epoch ----------------------------------------------------------------------------------------------------

        # Scheduler
        lr = [x["lr"] for x in optimizer.param_groups]  # for tensorboard
        scheduler.step()

        # DDP process 0 or single-GPU
        if rank in [-1, 0]:
            # mAP
            if ema:
                ema.update_attr(
                    model,
                    include=[
                        "yaml",
                        "nc",
                        "hyp",
                        "gr",
                        "names",
                        "stride",
                        "class_weights",
                    ],
                )
            final_epoch = epoch + 1 == epochs
            if not opt.notest or final_epoch:  # Calculate mAP
                results, maps, times = test.test(
                    opt.data,
                    batch_size=batch_size * 2,
                    imgsz=imgsz_test,
                    model=ema.ema,
                    single_cls=opt.single_cls,
                    dataloader=testloader,
                    save_dir=save_dir,
                    verbose=nc < 50 and final_epoch,
                    plots=plots and final_epoch,
                    log_imgs=opt.log_imgs if wandb else 0,
                    compute_loss=compute_loss,
                )

            # Write
            with open(results_file, "a") as f:
                f.write(
                    s + "%10.4g" * 7 % results +
                    "\n")  # P, R, [email protected], [email protected], val_loss(box, obj, cls)
            if len(opt.name) and opt.bucket:
                os.system("gsutil cp %s gs://%s/results/results%s.txt" %
                          (results_file, opt.bucket, opt.name))

            # Log
            tags = [
                "train/box_loss",
                "train/obj_loss",
                "train/cls_loss",  # train loss
                "metrics/precision",
                "metrics/recall",
                "metrics/mAP_0.5",
                "metrics/mAP_0.5:0.95",
                "val/box_loss",
                "val/obj_loss",
                "val/cls_loss",  # val loss
                "x/lr0",
                "x/lr1",
                "x/lr2",
            ]  # params
            for x, tag in zip(list(mloss[:-1]) + list(results) + lr, tags):
                if tb_writer:
                    tb_writer.add_scalar(tag, x, epoch)  # tensorboard
                if wandb:
                    wandb.log({tag: x}, step=epoch,
                              commit=tag == tags[-1])  # W&B

            # Update best mAP
            fi = fitness(np.array(results).reshape(
                1, -1))  # weighted combination of [P, R, [email protected], [email protected]]
            if fi > best_fitness:
                best_fitness = fi

            # Save model
            save = (not opt.nosave) or (final_epoch and not opt.evolve)
            if save:
                with open(results_file, "r") as f:  # create checkpoint
                    ckpt = {
                        "epoch":
                        epoch,
                        "best_fitness":
                        best_fitness,
                        "training_results":
                        f.read(),
                        "model":
                        ema.ema,
                        "optimizer":
                        None if final_epoch else optimizer.state_dict(),
                        "wandb_id":
                        wandb_run.id if wandb else None,
                    }

                # Save last, best and delete
                torch.save(ckpt, last)
                if best_fitness == fi:
                    torch.save(ckpt, best)
                del ckpt
        # end epoch ----------------------------------------------------------------------------------------------------
    # end training

    if rank in [-1, 0]:
        # Strip optimizers
        final = best if best.exists() else last  # final model
        for f in [last, best]:
            if f.exists():
                strip_optimizer(f)  # strip optimizers
        if opt.bucket:
            os.system(f"gsutil cp {final} gs://{opt.bucket}/weights")  # upload

        # Plots
        if plots:
            plot_results(save_dir=save_dir)  # save as results.png
            if wandb:
                files = [
                    "results.png",
                    "confusion_matrix.png",
                    *[f"{x}_curve.png" for x in ("F1", "PR", "P", "R")],
                ]
                wandb.log({
                    "Results": [
                        wandb.Image(str(save_dir / f), caption=f)
                        for f in files if (save_dir / f).exists()
                    ]
                })
                if opt.log_artifacts:
                    wandb.log_artifact(artifact_or_path=str(final),
                                       type="model",
                                       name=save_dir.stem)

        # Test best.pt
        logger.info("%g epochs completed in %.3f hours.\n" %
                    (epoch - start_epoch + 1, (time.time() - t0) / 3600))
        if opt.data.endswith("coco.yaml") and nc == 80:  # if COCO
            for conf, iou, save_json in (
                [0.25, 0.45, False],
                [0.001, 0.65, True],
            ):  # speed, mAP tests
                results, _, _ = test.test(
                    opt.data,
                    batch_size=batch_size * 2,
                    imgsz=imgsz_test,
                    conf_thres=conf,
                    iou_thres=iou,
                    model=attempt_load(final, device).half(),
                    single_cls=opt.single_cls,
                    dataloader=testloader,
                    save_dir=save_dir,
                    save_json=save_json,
                    plots=False,
                )

    else:
        dist.destroy_process_group()

    wandb.run.finish() if wandb and wandb.run else None
    torch.cuda.empty_cache()

    # mlflow
    with mlflow.start_run() as run:
        # Log args into mlflow
        for key, value in hyp.items():
            mlflow.log_param(key, value)

        for key, value in vars(opt).items():
            mlflow.log_param(key, value)

        # Log results into mlflow
        for x, tag in zip(list(mloss[:-1]) + list(results) + lr, tags):
            # xがtorch.Tensorだったらfloatに直す
            if torch.is_tensor(x):
                x = x.item()

            # tag名に特殊記号があれば削除する
            if ":" in tag:
                tag = re.sub(r":", " ", tag)

            mlflow.log_metric(tag, x)

        # Log model
        mlflow.pytorch.log_model(model, "model")

    return results
def train(hyp, opt, device, callbacks):  # hyp is path/to/hyp.yaml or hyp dictionary
    save_dir, epochs, batch_size, weights, single_cls, evolve, data, cfg, resume, noval, nosave, workers, freeze = \
        Path(opt.save_dir), opt.epochs, opt.batch_size, opt.weights, opt.single_cls, opt.evolve, opt.data, opt.cfg, \
        opt.resume, opt.noval, opt.nosave, opt.workers, opt.freeze
    callbacks.run('on_pretrain_routine_start')

    # Directories
    w = save_dir / 'weights'  # weights dir
    (w.parent if evolve else w).mkdir(parents=True, exist_ok=True)  # make dir
    last, best = w / 'last.pt', w / 'best.pt'

    # Hyperparameters
    if isinstance(hyp, str):
        with open(hyp, errors='ignore') as f:
            hyp = yaml.safe_load(f)  # load hyps dict
    LOGGER.info(colorstr('hyperparameters: ') + ', '.join(f'{k}={v}' for k, v in hyp.items()))

    # Save run settings
    if not evolve:
        with open(save_dir / 'hyp.yaml', 'w') as f:
            yaml.safe_dump(hyp, f, sort_keys=False)
        with open(save_dir / 'opt.yaml', 'w') as f:
            yaml.safe_dump(vars(opt), f, sort_keys=False)

    # Loggers
    data_dict = None
    if RANK in {-1, 0}:
        loggers = Loggers(save_dir, weights, opt, hyp, LOGGER)  # loggers instance
        if loggers.wandb:
            data_dict = loggers.wandb.data_dict
            if resume:
                weights, epochs, hyp, batch_size = opt.weights, opt.epochs, opt.hyp, opt.batch_size

        # Register actions
        for k in methods(loggers):
            callbacks.register_action(k, callback=getattr(loggers, k))

    # Config
    plots = not evolve and not opt.noplots  # create plots
    cuda = device.type != 'cpu'
    init_seeds(1 + RANK)
    with torch_distributed_zero_first(LOCAL_RANK):
        data_dict = data_dict or check_dataset(data)  # check if None
    train_path, val_path = data_dict['train'], data_dict['val']
    nc = 1 if single_cls else int(data_dict['nc'])  # number of classes
    names = ['item'] if single_cls and len(data_dict['names']) != 1 else data_dict['names']  # class names
    assert len(names) == nc, f'{len(names)} names found for nc={nc} dataset in {data}'  # check
    is_coco = isinstance(val_path, str) and val_path.endswith('coco/val2017.txt')  # COCO dataset

    # Model
    check_suffix(weights, '.pt')  # check weights
    pretrained = weights.endswith('.pt')
    if pretrained:
        with torch_distributed_zero_first(LOCAL_RANK):
            weights = attempt_download(weights)  # download if not found locally
        print('weights = ', weights)
        ckpt = torch.load(weights, map_location='cpu')  # load checkpoint to CPU to avoid CUDA memory leak
        model = Model(cfg or ckpt['model'].yaml, ch=3, nc=nc, anchors=hyp.get('anchors')).to(device)  # create
        exclude = ['anchor'] if (cfg or hyp.get('anchors')) and not resume else []  # exclude keys
        csd = ckpt['model'].float().state_dict()  # checkpoint state_dict as FP32
        csd = intersect_dicts(csd, model.state_dict(), exclude=exclude)  # intersect
        model.load_state_dict(csd, strict=False)  # load
        LOGGER.info(f'Transferred {len(csd)}/{len(model.state_dict())} items from {weights}')  # report
    else:
        model = Model(cfg, ch=3, nc=nc, anchors=hyp.get('anchors')).to(device)  # create

    # 加载教师模型,用于知识蒸馏
    from models.common import DetectMultiBackend
    model_t = DetectMultiBackend(weights=ROOT / 'yolov5x.pt', device=device)
    print('成功加载教师模型' + '!' * 100)

    # Freeze
    freeze = [f'model.{x}.' for x in (freeze if len(freeze) > 1 else range(freeze[0]))]  # layers to freeze
    for k, v in model.named_parameters():
        v.requires_grad = True  # train all layers
        if any(x in k for x in freeze):
            LOGGER.info(f'freezing {k}')
            v.requires_grad = False

    # Image size
    gs = max(int(model.stride.max()), 32)  # grid size (max stride)
    imgsz = check_img_size(opt.imgsz, gs, floor=gs * 2)  # verify imgsz is gs-multiple

    # Batch size
    if RANK == -1 and batch_size == -1:  # single-GPU only, estimate best batch size
        batch_size = check_train_batch_size(model, imgsz)
        loggers.on_params_update({"batch_size": batch_size})

    # Optimizer
    nbs = 64  # nominal batch size
    accumulate = max(round(nbs / batch_size), 1)  # accumulate loss before optimizing
    hyp['weight_decay'] *= batch_size * accumulate / nbs  # scale weight_decay
    LOGGER.info(f"Scaled weight_decay = {hyp['weight_decay']}")

    g = [], [], []  # optimizer parameter groups
    bn = tuple(v for k, v in nn.__dict__.items() if 'Norm' in k)  # normalization layers, i.e. BatchNorm2d()
    for v in model.modules():
        if hasattr(v, 'bias') and isinstance(v.bias, nn.Parameter):  # bias
            g[2].append(v.bias)
        if isinstance(v, bn):  # weight (no decay)
            g[1].append(v.weight)
        elif hasattr(v, 'weight') and isinstance(v.weight, nn.Parameter):  # weight (with decay)
            g[0].append(v.weight)

    if opt.optimizer == 'Adam':
        optimizer = Adam(g[2], lr=hyp['lr0'], betas=(hyp['momentum'], 0.999))  # adjust beta1 to momentum
    elif opt.optimizer == 'AdamW':
        optimizer = AdamW(g[2], lr=hyp['lr0'], betas=(hyp['momentum'], 0.999))  # adjust beta1 to momentum
    else:
        optimizer = SGD(g[2], lr=hyp['lr0'], momentum=hyp['momentum'], nesterov=True)

    optimizer.add_param_group({'params': g[0], 'weight_decay': hyp['weight_decay']})  # add g0 with weight_decay
    optimizer.add_param_group({'params': g[1]})  # add g1 (BatchNorm2d weights)
    LOGGER.info(f"{colorstr('optimizer:')} {type(optimizer).__name__} with parameter groups "
                f"{len(g[1])} weight (no decay), {len(g[0])} weight, {len(g[2])} bias")
    del g

    # Scheduler
    if opt.cos_lr:
        lf = one_cycle(1, hyp['lrf'], epochs)  # cosine 1->hyp['lrf']
    else:
        lf = lambda x: (1 - x / epochs) * (1.0 - hyp['lrf']) + hyp['lrf']  # linear
    scheduler = lr_scheduler.LambdaLR(optimizer, lr_lambda=lf)  # plot_lr_scheduler(optimizer, scheduler, epochs)

    # EMA
    ema = ModelEMA(model) if RANK in {-1, 0} else None

    # Resume
    start_epoch, best_fitness = 0, 0.0
    if pretrained:
        # Optimizer
        if ckpt['optimizer'] is not None:
            optimizer.load_state_dict(ckpt['optimizer'])
            best_fitness = ckpt['best_fitness']

        # EMA
        if ema and ckpt.get('ema'):
            ema.ema.load_state_dict(ckpt['ema'].float().state_dict())
            ema.updates = ckpt['updates']

        # Epochs
        start_epoch = ckpt['epoch'] + 1
        if resume:
            assert start_epoch > 0, f'{weights} training to {epochs} epochs is finished, nothing to resume.'
        if epochs < start_epoch:
            LOGGER.info(f"{weights} has been trained for {ckpt['epoch']} epochs. Fine-tuning for {epochs} more epochs.")
            epochs += ckpt['epoch']  # finetune additional epochs

        del ckpt, csd

    # DP mode
    if cuda and RANK == -1 and torch.cuda.device_count() > 1:
        LOGGER.warning('WARNING: DP not recommended, use torch.distributed.run for best DDP Multi-GPU results.\n'
                       'See Multi-GPU Tutorial at https://github.com/ultralytics/yolov5/issues/475 to get started.')
        model = torch.nn.DataParallel(model)

    # SyncBatchNorm
    if opt.sync_bn and cuda and RANK != -1:
        model = torch.nn.SyncBatchNorm.convert_sync_batchnorm(model).to(device)
        LOGGER.info('Using SyncBatchNorm()')

    # Trainloader
    train_loader, dataset = create_dataloader(train_path,
                                              imgsz,
                                              batch_size // WORLD_SIZE,
                                              gs,
                                              single_cls,
                                              hyp=hyp,
                                              augment=True,
                                              cache=None if opt.cache == 'val' else opt.cache,
                                              rect=opt.rect,
                                              rank=LOCAL_RANK,
                                              workers=workers,
                                              image_weights=opt.image_weights,
                                              quad=opt.quad,
                                              prefix=colorstr('train: '),
                                              shuffle=True)
    mlc = int(np.concatenate(dataset.labels, 0)[:, 0].max())  # max label class
    nb = len(train_loader)  # number of batches
    assert mlc < nc, f'Label class {mlc} exceeds nc={nc} in {data}. Possible class labels are 0-{nc - 1}'

    # Process 0
    if RANK in {-1, 0}:
        val_loader = create_dataloader(val_path,
                                       imgsz,
                                       batch_size // WORLD_SIZE * 2,
                                       gs,
                                       single_cls,
                                       hyp=hyp,
                                       cache=None if noval else opt.cache,
                                       rect=True,
                                       rank=-1,
                                       workers=workers * 2,
                                       pad=0.5,
                                       prefix=colorstr('val: '))[0]

        if not resume:
            labels = np.concatenate(dataset.labels, 0)
            # c = torch.tensor(labels[:, 0])  # classes
            # cf = torch.bincount(c.long(), minlength=nc) + 1.  # frequency
            # model._initialize_biases(cf.to(device))
            if plots:
                plot_labels(labels, names, save_dir)

            # Anchors
            if not opt.noautoanchor:
                check_anchors(dataset, model=model, thr=hyp['anchor_t'], imgsz=imgsz)
            model.half().float()  # pre-reduce anchor precision

        callbacks.run('on_pretrain_routine_end')

    # DDP mode
    if cuda and RANK != -1:
        if check_version(torch.__version__, '1.11.0'):
            model = DDP(model, device_ids=[LOCAL_RANK], output_device=LOCAL_RANK, static_graph=True)
        else:
            model = DDP(model, device_ids=[LOCAL_RANK], output_device=LOCAL_RANK)

    # Model attributes
    nl = de_parallel(model).model[-1].nl  # number of detection layers (to scale hyps)
    hyp['box'] *= 3 / nl  # scale to layers
    hyp['cls'] *= nc / 80 * 3 / nl  # scale to classes and layers
    hyp['obj'] *= (imgsz / 640) ** 2 * 3 / nl  # scale to image size and layers
    hyp['label_smoothing'] = opt.label_smoothing
    model.nc = nc  # attach number of classes to model
    model.hyp = hyp  # attach hyperparameters to model
    model.class_weights = labels_to_class_weights(dataset.labels, nc).to(device) * nc  # attach class weights
    model.names = names

    # Start training
    t0 = time.time()
    nw = max(round(hyp['warmup_epochs'] * nb), 100)  # number of warmup iterations, max(3 epochs, 100 iterations)
    # nw = min(nw, (epochs - start_epoch) / 2 * nb)  # limit warmup to < 1/2 of training
    last_opt_step = -1
    maps = np.zeros(nc)  # mAP per class
    results = (0, 0, 0, 0, 0, 0, 0)  # P, R, [email protected], [email protected], val_loss(box, obj, cls)
    scheduler.last_epoch = start_epoch - 1  # do not move
    scaler = amp.GradScaler(enabled=cuda)
    stopper = EarlyStopping(patience=opt.patience)

    compute_loss = ComputeLoss(model)  # init loss class
    callbacks.run('on_train_start')
    LOGGER.info(f'Image sizes {imgsz} train, {imgsz} val\n'
                f'Using {train_loader.num_workers * WORLD_SIZE} dataloader workers\n'
                f"Logging results to {colorstr('bold', save_dir)}\n"
                f'Starting training for {epochs} epochs...')
    for epoch in range(start_epoch, epochs):  # epoch ------------------------------------------------------------------
        callbacks.run('on_train_epoch_start')
        model.train()

        # Update image weights (optional, single-GPU only)
        if opt.image_weights:
            cw = model.class_weights.cpu().numpy() * (1 - maps) ** 2 / nc  # class weights
            iw = labels_to_image_weights(dataset.labels, nc=nc, class_weights=cw)  # image weights
            dataset.indices = random.choices(range(dataset.n), weights=iw, k=dataset.n)  # rand weighted idx

        # Update mosaic border (optional)
        # b = int(random.uniform(0.25 * imgsz, 0.75 * imgsz + gs) // gs * gs)
        # dataset.mosaic_border = [b - imgsz, -b]  # height, width borders

        mloss = torch.zeros(3, device=device)  # mean losses
        if RANK != -1:
            train_loader.sampler.set_epoch(epoch)
        pbar = enumerate(train_loader)
        LOGGER.info(('\n' + '%10s' * 7) % ('Epoch', 'gpu_mem', 'box', 'obj', 'cls', 'labels', 'img_size'))
        if RANK in {-1, 0}:
            pbar = tqdm(pbar, total=nb, bar_format='{l_bar}{bar:10}{r_bar}{bar:-10b}')  # progress bar
        optimizer.zero_grad()
        for i, (imgs, targets, paths, _) in pbar:  # batch -------------------------------------------------------------
            callbacks.run('on_train_batch_start')
            ni = i + nb * epoch  # number integrated batches (since train start)
            imgs = imgs.to(device, non_blocking=True).float() / 255  # uint8 to float32, 0-255 to 0.0-1.0

            # Warmup
            if ni <= nw:
                xi = [0, nw]  # x interp
                # compute_loss.gr = np.interp(ni, xi, [0.0, 1.0])  # iou loss ratio (obj_loss = 1.0 or iou)
                accumulate = max(1, np.interp(ni, xi, [1, nbs / batch_size]).round())
                for j, x in enumerate(optimizer.param_groups):
                    # bias lr falls from 0.1 to lr0, all other lrs rise from 0.0 to lr0
                    x['lr'] = np.interp(ni, xi, [hyp['warmup_bias_lr'] if j == 2 else 0.0, x['initial_lr'] * lf(epoch)])
                    if 'momentum' in x:
                        x['momentum'] = np.interp(ni, xi, [hyp['warmup_momentum'], hyp['momentum']])

            # Multi-scale
            if opt.multi_scale:
                sz = random.randrange(imgsz * 0.5, imgsz * 1.5 + gs) // gs * gs  # size
                sf = sz / max(imgs.shape[2:])  # scale factor
                if sf != 1:
                    ns = [math.ceil(x * sf / gs) * gs for x in imgs.shape[2:]]  # new shape (stretched to gs-multiple)
                    imgs = nn.functional.interpolate(imgs, size=ns, mode='bilinear', align_corners=False)

            # Forward
            with amp.autocast(enabled=cuda):
                pred = model(imgs)  # forward
                with torch.no_grad():
                    preds = model_t(imgs).detach()  # forward
                    bz = preds.size(0)
                    pred_t = [preds[:, :3*80*80, :].reshape(bz, 3, 80, 80, 85),
                              preds[:, 3*80*80:3*80*80+3*40*40, :].reshape(bz, 3, 40, 40, 85),
                              preds[:, 3*80*80+3*40*40:, :].reshape(bz, 3, 20, 20, 85)]

                # print('Length of (pred) = ', len(pred))
                # for k in range(len(pred)):
                #     print(f'pred[{k}].shape = ', pred[k].shape)
                #
                # print('Length of (pred_t) = ', len(pred_t))
                # for k in range(len(pred_t)):
                #     print(f'pred_t[{k}].shape = ', pred_t[k].shape)
                #
                # print(f"Len of target = {colorstr('red', targets.size(0))}  targets.shape = {targets.shape}")
                # for k in range(4):
                #     print(f'Example: example of target_{k} = {targets[k]}')

                loss, loss_items = compute_loss(pred, targets.to(device))  # loss scaled by batch_size
                loss_kd = KDLoss(pred_t, pred)

                # print(f"{colorstr('red', loss.item())} {colorstr('red', loss_kd.item())}")
                loss = loss + loss_kd
                # print(f"{colorstr('red', pred[0].shape)}  {colorstr('red', pred_t[0].shape)} ")
                # loss_t, loss_items_t = compute_loss(pred, pred2target(pred=pred_t, n=targets.size(0)))  # 计算教师模型和学生模型的蒸馏损失

                if RANK != -1:
                    loss *= WORLD_SIZE  # gradient averaged between devices in DDP mode
                if opt.quad:
                    loss *= 4.

            # Backward
            scaler.scale(loss).backward()

            # Optimize
            if ni - last_opt_step >= accumulate:
                scaler.step(optimizer)  # optimizer.step
                scaler.update()
                optimizer.zero_grad()
                if ema:
                    ema.update(model)
                last_opt_step = ni

            # Log
            if RANK in {-1, 0}:
                mloss = (mloss * i + loss_items) / (i + 1)  # update mean losses
                mem = f'{torch.cuda.memory_reserved() / 1E9 if torch.cuda.is_available() else 0:.3g}G'  # (GB)
                pbar.set_description(('%10s' * 2 + '%10.4g' * 5) %
                                     (f'{epoch}/{epochs - 1}', mem, *mloss, targets.shape[0], imgs.shape[-1]))
                callbacks.run('on_train_batch_end', ni, model, imgs, targets, paths, plots)
                if callbacks.stop_training:
                    return
            # end batch ------------------------------------------------------------------------------------------------

        # Scheduler
        lr = [x['lr'] for x in optimizer.param_groups]  # for loggers
        scheduler.step()

        if RANK in {-1, 0}:
            # mAP
            callbacks.run('on_train_epoch_end', epoch=epoch)
            ema.update_attr(model, include=['yaml', 'nc', 'hyp', 'names', 'stride', 'class_weights'])
            final_epoch = (epoch + 1 == epochs) or stopper.possible_stop
            if not noval or final_epoch:  # Calculate mAP
                results, maps, _ = val.run(data_dict,
                                           batch_size=batch_size // WORLD_SIZE * 2,
                                           imgsz=imgsz,
                                           model=ema.ema,
                                           single_cls=single_cls,
                                           dataloader=val_loader,
                                           save_dir=save_dir,
                                           plots=False,
                                           callbacks=callbacks,
                                           compute_loss=compute_loss)

            # Update best mAP
            fi = fitness(np.array(results).reshape(1, -1))  # weighted combination of [P, R, [email protected], [email protected]]
            if fi > best_fitness:
                best_fitness = fi
            log_vals = list(mloss) + list(results) + lr
            callbacks.run('on_fit_epoch_end', log_vals, epoch, best_fitness, fi)

            # Save model
            if (not nosave) or (final_epoch and not evolve):  # if save
                ckpt = {
                    'epoch': epoch,
                    'best_fitness': best_fitness,
                    'model': deepcopy(de_parallel(model)).half(),
                    'ema': deepcopy(ema.ema).half(),
                    'updates': ema.updates,
                    'optimizer': optimizer.state_dict(),
                    'wandb_id': loggers.wandb.wandb_run.id if loggers.wandb else None,
                    'date': datetime.now().isoformat()}

                # Save last, best and delete
                torch.save(ckpt, last)
                if best_fitness == fi:
                    torch.save(ckpt, best)
                if (epoch > 0) and (opt.save_period > 0) and (epoch % opt.save_period == 0):
                    torch.save(ckpt, w / f'epoch{epoch}.pt')
                del ckpt
                callbacks.run('on_model_save', last, epoch, final_epoch, best_fitness, fi)

            # Stop Single-GPU
            if RANK == -1 and stopper(epoch=epoch, fitness=fi):
                break

            # Stop DDP TODO: known issues shttps://github.com/ultralytics/yolov5/pull/4576
            # stop = stopper(epoch=epoch, fitness=fi)
            # if RANK == 0:
            #    dist.broadcast_object_list([stop], 0)  # broadcast 'stop' to all ranks

        # Stop DPP
        # with torch_distributed_zero_first(RANK):
        # if stop:
        #    break  # must break all DDP ranks

        # end epoch ----------------------------------------------------------------------------------------------------
    # end training -----------------------------------------------------------------------------------------------------
    if RANK in {-1, 0}:
        LOGGER.info(f'\n{epoch - start_epoch + 1} epochs completed in {(time.time() - t0) / 3600:.3f} hours.')
        for f in last, best:
            if f.exists():
                strip_optimizer(f)  # strip optimizers
                if f is best:
                    LOGGER.info(f'\nValidating {f}...')
                    results, _, _ = val.run(
                        data_dict,
                        batch_size=batch_size // WORLD_SIZE * 2,
                        imgsz=imgsz,
                        model=attempt_load(f, device).half(),
                        iou_thres=0.65 if is_coco else 0.60,  # best pycocotools results at 0.65
                        single_cls=single_cls,
                        dataloader=val_loader,
                        save_dir=save_dir,
                        save_json=is_coco,
                        verbose=True,
                        plots=plots,
                        callbacks=callbacks,
                        compute_loss=compute_loss)  # val best model with plots
                    if is_coco:
                        callbacks.run('on_fit_epoch_end', list(mloss) + list(results) + lr, epoch, best_fitness, fi)

        callbacks.run('on_train_end', last, best, plots, epoch, results)

    torch.cuda.empty_cache()
    return results
def train(
    hyp,  # path/to/hyp.yaml or hyp dictionary
    opt,
    device,
):
    save_dir, epochs, batch_size, weights, single_cls, evolve, data, cfg, resume, noval, nosave, workers, = \
        Path(opt.save_dir), opt.epochs, opt.batch_size, opt.weights, opt.single_cls, opt.evolve, opt.data, opt.cfg, \
        opt.resume, opt.noval, opt.nosave, opt.workers

    # Directories
    w = save_dir / 'weights'  # weights dir
    w.mkdir(parents=True, exist_ok=True)  # make dir
    last, best = w / 'last.pt', w / 'best.pt'

    # Hyperparameters
    if isinstance(hyp, str):
        with open(hyp) as f:
            hyp = yaml.safe_load(f)  # load hyps dict
    LOGGER.info(
        colorstr('hyperparameters: ') + ', '.join(f'{k}={v}'
                                                  for k, v in hyp.items()))

    # Save run settings
    with open(save_dir / 'hyp.yaml', 'w') as f:
        yaml.safe_dump(hyp, f, sort_keys=False)
    with open(save_dir / 'opt.yaml', 'w') as f:
        yaml.safe_dump(vars(opt), f, sort_keys=False)

    # Config
    plots = not evolve  # create plots
    cuda = device.type != 'cpu'
    init_seeds(1 + RANK)
    with torch_distributed_zero_first(RANK):
        data_dict = check_dataset(data)  # check
    train_path, val_path = data_dict['train'], data_dict['val']
    nc = 1 if single_cls else int(data_dict['nc'])  # number of classes
    names = ['item'] if single_cls and len(
        data_dict['names']) != 1 else data_dict['names']  # class names
    assert len(
        names
    ) == nc, f'{len(names)} names found for nc={nc} dataset in {data}'  # check
    # is_coco = data.endswith('coco.yaml') and nc == 80  # COCO dataset
    is_coco = data.endswith('top3.yaml') and nc == 5  # COCO dataset
    # Loggers
    if RANK in [-1, 0]:
        loggers = Loggers(save_dir, weights, opt, hyp, data_dict,
                          LOGGER).start()  # loggers dict
        if loggers.wandb and resume:
            weights, epochs, hyp, data_dict = opt.weights, opt.epochs, opt.hyp, loggers.wandb.data_dict

    # Model
    pretrained = weights.endswith('.pt')
    pretrained = False
    if pretrained:
        with torch_distributed_zero_first(RANK):
            weights = attempt_download(
                weights)  # download if not found locally
        ckpt = torch.load(weights, map_location=device)  # load checkpoint
        model = Model(cfg or ckpt['model'].yaml,
                      ch=3,
                      nc=nc,
                      anchors=hyp.get('anchors')).to(device)  # create
        exclude = [
            'anchor'
        ] if (cfg or hyp.get('anchors')) and not resume else []  # exclude keys
        csd = ckpt['model'].float().state_dict(
        )  # checkpoint state_dict as FP32
        csd = intersect_dicts(csd, model.state_dict(),
                              exclude=exclude)  # intersect
        model.load_state_dict(csd, strict=False)  # load
        LOGGER.info(
            f'Transferred {len(csd)}/{len(model.state_dict())} items from {weights}'
        )  # report
    else:
        model = Model(cfg, ch=3, nc=nc,
                      anchors=hyp.get('anchors')).to(device)  # create

    # Freeze
    freeze = []  # parameter names to freeze (full or partial)
    for k, v in model.named_parameters():
        v.requires_grad = True  # train all layers
        if any(x in k for x in freeze):
            print(f'freezing {k}')
            v.requires_grad = False

    # Optimizer
    nbs = 64  # nominal batch size
    accumulate = max(round(nbs / batch_size),
                     1)  # accumulate loss before optimizing
    hyp['weight_decay'] *= batch_size * accumulate / nbs  # scale weight_decay
    LOGGER.info(f"Scaled weight_decay = {hyp['weight_decay']}")

    g0, g1, g2 = [], [], []  # optimizer parameter groups
    for v in model.modules():
        if hasattr(v, 'bias') and isinstance(v.bias, nn.Parameter):  # bias
            g2.append(v.bias)
        if isinstance(v, nn.BatchNorm2d):  # weight with decay
            g0.append(v.weight)
        elif hasattr(v, 'weight') and isinstance(
                v.weight, nn.Parameter):  # weight without decay
            g1.append(v.weight)

    if opt.adam:
        optimizer = Adam(g0, lr=hyp['lr0'],
                         betas=(hyp['momentum'],
                                0.999))  # adjust beta1 to momentum
    else:
        optimizer = SGD(g0,
                        lr=hyp['lr0'],
                        momentum=hyp['momentum'],
                        nesterov=True)

    optimizer.add_param_group({
        'params': g1,
        'weight_decay': hyp['weight_decay']
    })  # add g1 with weight_decay
    optimizer.add_param_group({'params': g2})  # add g2 (biases)
    LOGGER.info(
        f"{colorstr('optimizer:')} {type(optimizer).__name__} with parameter groups "
        f"{len(g0)} weight, {len(g1)} weight (no decay), {len(g2)} bias")
    del g0, g1, g2

    # Scheduler
    if opt.linear_lr:
        lf = lambda x: (1 - x / (epochs - 1)) * (1.0 - hyp['lrf']) + hyp[
            'lrf']  # linear
    else:
        lf = one_cycle(1, hyp['lrf'], epochs)  # cosine 1->hyp['lrf']
    scheduler = lr_scheduler.LambdaLR(
        optimizer,
        lr_lambda=lf)  # plot_lr_scheduler(optimizer, scheduler, epochs)

    # EMA
    ema = ModelEMA(model) if RANK in [-1, 0] else None

    # Resume
    start_epoch, best_fitness = 0, 0.0
    if pretrained:
        # Optimizer
        if ckpt['optimizer'] is not None:
            optimizer.load_state_dict(ckpt['optimizer'])
            best_fitness = ckpt['best_fitness']

        # EMA
        if ema and ckpt.get('ema'):
            ema.ema.load_state_dict(ckpt['ema'].float().state_dict())
            ema.updates = ckpt['updates']

        # Epochs
        start_epoch = ckpt['epoch'] + 1
        if resume:
            assert start_epoch > 0, f'{weights} training to {epochs} epochs is finished, nothing to resume.'
        if epochs < start_epoch:
            LOGGER.info(
                f"{weights} has been trained for {ckpt['epoch']} epochs. Fine-tuning for {epochs} more epochs."
            )
            epochs += ckpt['epoch']  # finetune additional epochs

        del ckpt, csd

    # Image sizes
    gs = max(int(model.stride.max()), 32)  # grid size (max stride)
    nl = model.model[
        -1].nl  # number of detection layers (used for scaling hyp['obj'])
    imgsz = check_img_size(opt.imgsz, gs,
                           floor=gs * 2)  # verify imgsz is gs-multiple

    # DP mode
    if cuda and RANK == -1 and torch.cuda.device_count() > 1:
        logging.warning(
            'DP not recommended, instead use torch.distributed.run for best DDP Multi-GPU results.\n'
            'See Multi-GPU Tutorial at https://github.com/ultralytics/yolov5/issues/475 to get started.'
        )
        model = torch.nn.DataParallel(model)

    # SyncBatchNorm
    if opt.sync_bn and cuda and RANK != -1:
        model = torch.nn.SyncBatchNorm.convert_sync_batchnorm(model).to(device)
        LOGGER.info('Using SyncBatchNorm()')

    # Trainloader
    train_loader, dataset = create_dataloader(train_path,
                                              imgsz,
                                              batch_size // WORLD_SIZE,
                                              gs,
                                              single_cls,
                                              hyp=hyp,
                                              augment=True,
                                              cache=opt.cache_images,
                                              rect=opt.rect,
                                              rank=RANK,
                                              workers=workers,
                                              image_weights=opt.image_weights,
                                              quad=opt.quad,
                                              prefix=colorstr('train: '))
    mlc = np.concatenate(dataset.labels, 0)[:, 0].max()  # max label class
    nb = len(train_loader)  # number of batches
    assert mlc < nc, f'Label class {mlc} exceeds nc={nc} in {data}. Possible class labels are 0-{nc - 1}'

    # Process 0
    if RANK in [-1, 0]:
        val_loader = create_dataloader(val_path,
                                       imgsz,
                                       batch_size // WORLD_SIZE * 2,
                                       gs,
                                       single_cls,
                                       hyp=hyp,
                                       cache=opt.cache_images and not noval,
                                       rect=True,
                                       rank=-1,
                                       workers=workers,
                                       pad=0.5,
                                       prefix=colorstr('val: '))[0]

        if not resume:
            labels = np.concatenate(dataset.labels, 0)
            # c = torch.tensor(labels[:, 0])  # classes
            # cf = torch.bincount(c.long(), minlength=nc) + 1.  # frequency
            # model._initialize_biases(cf.to(device))
            if plots:
                plot_labels(labels, names, save_dir, loggers)

            # Anchors
            if not opt.noautoanchor:
                check_anchors(dataset,
                              model=model,
                              thr=hyp['anchor_t'],
                              imgsz=imgsz)
            model.half().float()  # pre-reduce anchor precision

    # DDP mode
    if cuda and RANK != -1:
        model = DDP(model, device_ids=[LOCAL_RANK], output_device=LOCAL_RANK)

    # Model parameters
    hyp['box'] *= 3. / nl  # scale to layers
    hyp['cls'] *= nc / 80. * 3. / nl  # scale to classes and layers
    hyp['obj'] *= (imgsz / 640)**2 * 3. / nl  # scale to image size and layers
    hyp['label_smoothing'] = opt.label_smoothing
    model.nc = nc  # attach number of classes to model
    model.hyp = hyp  # attach hyperparameters to model
    model.class_weights = labels_to_class_weights(
        dataset.labels, nc).to(device) * nc  # attach class weights
    model.names = names

    # Start training
    t0 = time.time()
    nw = max(round(hyp['warmup_epochs'] * nb),
             1000)  # number of warmup iterations, max(3 epochs, 1k iterations)
    # nw = min(nw, (epochs - start_epoch) / 2 * nb)  # limit warmup to < 1/2 of training
    last_opt_step = -1
    maps = np.zeros(nc)  # mAP per class
    results = (0, 0, 0, 0, 0, 0, 0
               )  # P, R, [email protected], [email protected], val_loss(box, obj, cls)
    scheduler.last_epoch = start_epoch - 1  # do not move
    scaler = amp.GradScaler(enabled=cuda)
    compute_loss = ComputeLoss(model)  # init loss class
    LOGGER.info(f'Image sizes {imgsz} train, {imgsz} val\n'
                f'Using {train_loader.num_workers} dataloader workers\n'
                f'Logging results to {save_dir}\n'
                f'Starting training for {epochs} epochs...')
    for epoch in range(
            start_epoch, epochs
    ):  # epoch ------------------------------------------------------------------
        model.train()

        # Update image weights (optional)
        if opt.image_weights:
            # Generate indices
            if RANK in [-1, 0]:
                cw = model.class_weights.cpu().numpy() * (
                    1 - maps)**2 / nc  # class weights
                iw = labels_to_image_weights(dataset.labels,
                                             nc=nc,
                                             class_weights=cw)  # image weights
                dataset.indices = random.choices(
                    range(dataset.n), weights=iw,
                    k=dataset.n)  # rand weighted idx
            # Broadcast if DDP
            if RANK != -1:
                indices = (torch.tensor(dataset.indices)
                           if RANK == 0 else torch.zeros(dataset.n)).int()
                dist.broadcast(indices, 0)
                if RANK != 0:
                    dataset.indices = indices.cpu().numpy()

        # Update mosaic border
        # b = int(random.uniform(0.25 * imgsz, 0.75 * imgsz + gs) // gs * gs)
        # dataset.mosaic_border = [b - imgsz, -b]  # height, width borders

        mloss = torch.zeros(3, device=device)  # mean losses
        if RANK != -1:
            train_loader.sampler.set_epoch(epoch)
        pbar = enumerate(train_loader)
        LOGGER.info(
            ('\n' + '%10s' * 7) %
            ('Epoch', 'gpu_mem', 'box', 'obj', 'cls', 'labels', 'img_size'))
        if RANK in [-1, 0]:
            pbar = tqdm(pbar, total=nb)  # progress bar
        optimizer.zero_grad()
        for i, (
                imgs, targets, paths, _
        ) in pbar:  # batch -------------------------------------------------------------
            ni = i + nb * epoch  # number integrated batches (since train start)
            imgs = imgs.to(device, non_blocking=True).float(
            ) / 255.0  # uint8 to float32, 0-255 to 0.0-1.0

            # Warmup
            if ni <= nw:
                xi = [0, nw]  # x interp
                # compute_loss.gr = np.interp(ni, xi, [0.0, 1.0])  # iou loss ratio (obj_loss = 1.0 or iou)
                accumulate = max(
                    1,
                    np.interp(ni, xi, [1, nbs / batch_size]).round())
                for j, x in enumerate(optimizer.param_groups):
                    # bias lr falls from 0.1 to lr0, all other lrs rise from 0.0 to lr0
                    x['lr'] = np.interp(ni, xi, [
                        hyp['warmup_bias_lr'] if j == 2 else 0.0,
                        x['initial_lr'] * lf(epoch)
                    ])
                    if 'momentum' in x:
                        x['momentum'] = np.interp(
                            ni, xi, [hyp['warmup_momentum'], hyp['momentum']])

            # Multi-scale
            if opt.multi_scale:
                sz = random.randrange(imgsz * 0.5,
                                      imgsz * 1.5 + gs) // gs * gs  # size
                sf = sz / max(imgs.shape[2:])  # scale factor
                if sf != 1:
                    ns = [math.ceil(x * sf / gs) * gs for x in imgs.shape[2:]
                          ]  # new shape (stretched to gs-multiple)
                    imgs = nn.functional.interpolate(imgs,
                                                     size=ns,
                                                     mode='bilinear',
                                                     align_corners=False)

            # Forward
            with amp.autocast(enabled=cuda):
                pred = model(imgs)  # forward
                loss, loss_items = compute_loss(
                    pred, targets.to(device))  # loss scaled by batch_size
                if RANK != -1:
                    loss *= WORLD_SIZE  # gradient averaged between devices in DDP mode
                if opt.quad:
                    loss *= 4.

            # Backward
            scaler.scale(loss).backward()

            # Optimize
            if ni - last_opt_step >= accumulate:
                scaler.step(optimizer)  # optimizer.step
                scaler.update()
                optimizer.zero_grad()
                if ema:
                    ema.update(model)
                last_opt_step = ni

            # Log
            if RANK in [-1, 0]:
                mloss = (mloss * i + loss_items) / (i + 1
                                                    )  # update mean losses
                mem = f'{torch.cuda.memory_reserved() / 1E9 if torch.cuda.is_available() else 0:.3g}G'  # (GB)
                pbar.set_description(('%10s' * 2 + '%10.4g' * 5) %
                                     (f'{epoch}/{epochs - 1}', mem, *mloss,
                                      targets.shape[0], imgs.shape[-1]))
                loggers.on_train_batch_end(ni, model, imgs, targets, paths,
                                           plots)

            # end batch ------------------------------------------------------------------------------------------------

        # Scheduler
        lr = [x['lr'] for x in optimizer.param_groups]  # for loggers
        scheduler.step()

        if RANK in [-1, 0]:
            # mAP
            loggers.on_train_epoch_end(epoch)
            ema.update_attr(model,
                            include=[
                                'yaml', 'nc', 'hyp', 'names', 'stride',
                                'class_weights'
                            ])
            final_epoch = epoch + 1 == epochs
            if not noval or final_epoch:  # Calculate mAP
                results, maps, _ = val.run(data_dict,
                                           batch_size=batch_size //
                                           WORLD_SIZE * 2,
                                           imgsz=imgsz,
                                           model=ema.ema,
                                           single_cls=single_cls,
                                           dataloader=val_loader,
                                           save_dir=save_dir,
                                           save_json=is_coco and final_epoch,
                                           verbose=nc < 50 and final_epoch,
                                           plots=plots and final_epoch,
                                           loggers=loggers,
                                           compute_loss=compute_loss)

            # Update best mAP
            fi = fitness(np.array(results).reshape(
                1, -1))  # weighted combination of [P, R, [email protected], [email protected]]
            if fi > best_fitness:
                best_fitness = fi
            loggers.on_train_val_end(mloss, results, lr, epoch, best_fitness,
                                     fi)

            # Save model
            if (not nosave) or (final_epoch and not evolve):  # if save
                ckpt = {
                    'epoch':
                    epoch,
                    'best_fitness':
                    best_fitness,
                    'model':
                    deepcopy(de_parallel(model)).half(),
                    'ema':
                    deepcopy(ema.ema).half(),
                    'updates':
                    ema.updates,
                    'optimizer':
                    optimizer.state_dict(),
                    'wandb_id':
                    loggers.wandb.wandb_run.id if loggers.wandb else None
                }

                # Save last, best and delete
                torch.save(ckpt, last)
                if best_fitness == fi:
                    torch.save(ckpt, best)
                del ckpt
                loggers.on_model_save(last, epoch, final_epoch, best_fitness,
                                      fi)

        # end epoch ----------------------------------------------------------------------------------------------------
    # end training -----------------------------------------------------------------------------------------------------
    if RANK in [-1, 0]:
        LOGGER.info(
            f'{epoch - start_epoch + 1} epochs completed in {(time.time() - t0) / 3600:.3f} hours.\n'
        )
        if not evolve:
            if is_coco:  # COCO dataset
                for m in [last, best
                          ] if best.exists() else [last]:  # speed, mAP tests
                    results, _, _ = val.run(
                        data_dict,
                        batch_size=batch_size // WORLD_SIZE * 2,
                        imgsz=imgsz,
                        model=attempt_load(m, device).half(),
                        iou_thres=
                        0.7,  # NMS IoU threshold for best pycocotools results
                        single_cls=single_cls,
                        dataloader=val_loader,
                        save_dir=save_dir,
                        save_json=False,
                        plots=False)
            # Strip optimizers
            for f in last, best:
                if f.exists():
                    strip_optimizer(f)  # strip optimizers
        loggers.on_train_end(last, best, plots)

    torch.cuda.empty_cache()
    return results
Exemple #7
0
def train(hyp, opt, device, tb_writer=None):

    # Print hyperparameter data
    print(f'Hyperparameters {hyp}')

    # Initiate logging settings
    log_dir = Path(tb_writer.log_dir) if tb_writer else Path(
        opt.logdir) / 'evolve'  # log directory
    wdir = str(log_dir / 'weights') + os.sep  # weight directory
    os.makedirs(wdir, exist_ok=True)
    last = wdir + 'last.pt'
    best = wdir + 'best.pt'
    results_file = str(log_dir / 'results.txt')
    epochs, batch_size, total_batch_size, weights, rank = opt.epochs, opt.batch_size, opt.total_batch_size, opt.weights, opt.global_rank

    # Save hyperparameters and opts to logging directory
    with open(log_dir / 'hyp.yaml', 'w') as f:
        yaml.dump(hyp, f, sort_keys=False)
    with open(log_dir / 'opt.yaml', 'w') as f:
        yaml.dump(vars(opt), f, sort_keys=False)

    # Other configurations
    cuda = device.type != 'cpu'
    init_seeds(2 + rank)
    with open(opt.data) as f:
        data_dict = yaml.load(f, Loader=yaml.FullLoader)
    train_path = data_dict['train']
    test_path = data_dict['val']
    nc, names = (1, ['item']) if opt.single_cls else (int(data_dict['nc']),
                                                      data_dict['names'])
    assert len(names) == nc, '%g names found for nc=%g dataset in %s' % (
        len(names), nc, opt.data)

    # Initiate model
    # the model architecture in opt.cfg should match the architecture of the model in opt.weights
    pretrained = weights.endswith('.pt')
    if pretrained:
        with torch_distributed_zero_first(rank):
            attempt_download(weights)
        ckpt = torch.load(weights, map_location=device)
        model = Darknet(opt.cfg).to(device)
        state_dict = {
            k: v
            for k, v in ckpt['model'].items()
            if model.state_dict()[k].numel() == v.numel()
        }
        model.load_state_dict(state_dict, strict=False)
        print('Transferred %g/%g items from %s' %
              (len(state_dict), len(model.state_dict()), weights))
    else:
        model = Darknet(opt.cfg).to(device)

    # Optimizer configurations (weight decay is subtly changed to fit the accumulate value)
    nbs = 64  # nominal batch size
    accumulate = max(round(nbs / total_batch_size), 1)  # accumulate loss
    hyp['weight_decay'] *= total_batch_size * accumulate / nbs

    # 0, 1, 2 = other, weight, bias
    pg0, pg1, pg2 = [], [], []
    for k, v in dict(model.named_parameters()).items():
        if '.bias' in k:
            pg2.append(v)
        elif 'Conv2d.weight' in k:
            pg1.append(v)
        else:
            pg0.append(v)

    # Define optimizer
    if opt.adam:
        optimizer = optim.Adam(
            pg0, lr=hyp['lr0'],
            betas=(hyp['momentum'], 0.999))  # replace beta1 with hyp.momentum
    else:
        optimizer = optim.SGD(pg0,
                              lr=hyp['lr0'],
                              momentum=hyp['momentum'],
                              nesterov=True)
    optimizer.add_param_group({
        'params': pg1,
        'weight_decay': hyp['weight_decay']
    })  # add weight decay
    optimizer.add_param_group({'params': pg2})
    print('Optimizer groups: %g .bias, %g conv.weight, %g other' %
          (len(pg2), len(pg1), len(pg0)))
    del pg0, pg1, pg2

    lf = lambda x: ((
        (1 + math.cos(x * math.pi / epochs)) / 2)**1.0) * 0.8 + 0.2
    scheduler = lr_scheduler.LambdaLR(optimizer, lr_lambda=lf)
    # plot_lr_scheduler(optimizer, scheduler, epochs)

    # Configurations for resume training
    start_epoch, best_fitness = 0, 0.0
    if pretrained:
        if ckpt['optimizer'] is not None:
            optimizer.load_state_dict(ckpt['optimizer'])
            best_fitness = ckpt['best_fitness']
        if ckpt.get('training_results') is not None:
            with open(results_file, 'w') as file:
                file.write(ckpt['training_results'])
        start_epoch = ckpt['epoch'] + 1
        if epochs < start_epoch:
            print(
                '%s has been trained for %g epochs. Fine-tuning for %g additional epochs.'
                % (weights, ckpt['epoch'], epochs))
            epochs += ckpt['epoch']
        del ckpt, state_dict

    # Image sizes
    gs = 32  # grid size (max stride)
    imgsz, imgsz_test = [check_img_size(x, gs) for x in opt.img_size
                         ]  # verify imgsz are gs-multiples

    # DP mode (multiple GPU, not used)
    if cuda and rank == -1 and torch.cuda.device_count() > 1:
        model = torch.nn.DataParallel(model)

    # SyncBatchNorm
    if opt.sync_bn and cuda and rank != -1:
        model = torch.nn.SyncBatchNorm.convert_sync_batchnorm(model).to(device)
        print('Using SyncBatchNorm()')

    # Exponential moving average
    ema = ModelEMA(model) if rank in [-1, 0] else None

    # DDP mode
    if cuda and rank != -1:
        model = DDP(model,
                    device_ids=[opt.local_rank],
                    output_device=(opt.local_rank))

    # Trainloader
    dataloader, dataset = create_dataloader(train_path,
                                            imgsz,
                                            batch_size,
                                            gs,
                                            opt,
                                            hyp=hyp,
                                            augment=True,
                                            cache=opt.cache_images,
                                            rect=opt.rect,
                                            local_rank=rank,
                                            world_size=opt.world_size)
    mlc = np.concatenate(dataset.labels, 0)[:, 0].max()  # max label class
    nb = len(dataloader)  # number of batches
    assert mlc < nc, 'Label class %g exceeds nc=%g in %s. Possible class labels are 0-%g' % (
        mlc, nc, opt.data, nc - 1)

    # Testloader
    if rank in [-1, 0]:
        ema.updates = start_epoch * nb // accumulate  # set EMA updates ***
        # local_rank is set to -1. Because only the first process is expected to do evaluation.
        testloader = create_dataloader(test_path,
                                       imgsz_test,
                                       batch_size,
                                       gs,
                                       opt,
                                       hyp=hyp,
                                       augment=False,
                                       cache=opt.cache_images,
                                       rect=True,
                                       local_rank=-1,
                                       world_size=opt.world_size)[0]

    # Model parameters
    hyp['cls'] *= nc / 80.  # scale coco-tuned hyp['cls'] to current dataset; hyp['cls'] is the cls loss gain
    model.nc = nc  # attach number of classes to model
    model.hyp = hyp  # attach hyperparameters to model
    model.gr = 1.0  # giou loss ratio (obj_loss = 1.0 or giou)
    model.class_weights = labels_to_class_weights(dataset.labels, nc).to(
        device)  # attach class weights
    model.names = names

    # Class frequency
    if rank in [-1, 0]:
        labels = np.concatenate(dataset.labels, 0)
        c = torch.tensor(labels[:, 0])  # classes
        # cf = torch.bincount(c.long(), minlength=nc) + 1.
        # model._initialize_biases(cf.to(device))
        plot_labels(labels, save_dir=log_dir)
        if tb_writer:
            tb_writer.add_histogram('classes', c, 0)

        # Check anchors
        # if not opt.noautoanchor:
        #     check_anchors(dataset, model=model, thr=hyp['anchor_t'], imgsz=imgsz)

    # Start training
    t0 = time.time()
    nw = max(3 * nb,
             1e3)  # number of warmup iterations, max(3 epochs, 1k iterations)
    # nw = min(nw, (epochs - start_epoch) / 2 * nb)  # limit warmup to < 1/2 of training
    maps = np.zeros(nc)  # mAP per class
    results = (
        0, 0, 0, 0, 0, 0, 0
    )  # 'P', 'R', 'mAP', 'F1', 'val GIoU', 'val Objectness', 'val Classification'
    scheduler.last_epoch = start_epoch - 1  # do not move
    scaler = amp.GradScaler(enabled=cuda)
    if rank in [0, -1]:
        print('Image sizes %g train, %g test' % (imgsz, imgsz_test))
        print('Using %g dataloader workers' % dataloader.num_workers)
        print('Starting training for %g epochs...' % epochs)
    # torch.autograd.set_detect_anomaly(True)

    for epoch in range(
            start_epoch, epochs
    ):  # epoch ------------------------------------------------------------------
        model.train()

        # Update image weights (optional)
        if dataset.image_weights:
            # Generate indices
            if rank in [-1, 0]:
                w = model.class_weights.cpu().numpy() * (
                    1 - maps)**2  # class weights
                image_weights = labels_to_image_weights(dataset.labels,
                                                        nc=nc,
                                                        class_weights=w)
                dataset.indices = random.choices(
                    range(dataset.n), weights=image_weights,
                    k=dataset.n)  # rand weighted idx
            # Broadcast if DDP (not used)
            if rank != -1:
                indices = torch.zeros([dataset.n], dtype=torch.int)
                if rank == 0:
                    indices[:] = torch.from_tensor(dataset.indices,
                                                   dtype=torch.int)
                dist.broadcast(indices, 0)
                if rank != 0:
                    dataset.indices = indices.cpu().numpy()

        # Update mosaic border
        # b = int(random.uniform(0.25 * imgsz, 0.75 * imgsz + gs) // gs * gs)
        # dataset.mosaic_border = [b - imgsz, -b]  # height, width borders

        mloss = torch.zeros(4, device=device)  # mean losses
        if rank != -1:
            dataloader.sampler.set_epoch(epoch)
        pbar = enumerate(dataloader)
        if rank in [-1, 0]:
            print(
                ('\n' + '%10s' * 8) % ('Epoch', 'gpu_mem', 'GIoU', 'obj',
                                       'cls', 'total', 'targets', 'img_size'))
            pbar = tqdm(pbar, total=nb)  # progress bar
        optimizer.zero_grad()
        for i, (
                imgs, targets, paths, _
        ) in pbar:  # batch -------------------------------------------------------------
            ni = i + nb * epoch  # number integrated batches (since train start)
            imgs = imgs.to(device, non_blocking=True).float(
            ) / 255.0  # uint8 to float32, 0-255 to 0.0-1.0

            # Warmup
            if ni <= nw:
                xi = [0, nw]  # x interp
                # model.gr = np.interp(ni, xi, [0.0, 1.0])  # giou loss ratio (obj_loss = 1.0 or giou)
                accumulate = max(
                    1,
                    np.interp(ni, xi, [1, nbs / total_batch_size]).round())
                for j, x in enumerate(optimizer.param_groups):
                    # bias lr falls from 0.1 to lr0, all other lrs rise from 0.0 to lr0
                    x['lr'] = np.interp(
                        ni, xi,
                        [0.1 if j == 2 else 0.0, x['initial_lr'] * lf(epoch)])
                    if 'momentum' in x:
                        x['momentum'] = np.interp(ni, xi,
                                                  [0.9, hyp['momentum']])

            # Multi-scale
            if opt.multi_scale:
                sz = random.randrange(imgsz * 0.5,
                                      imgsz * 1.5 + gs) // gs * gs  # size
                sf = sz / max(imgs.shape[2:])  # scale factor
                if sf != 1:
                    ns = [math.ceil(x * sf / gs) * gs for x in imgs.shape[2:]
                          ]  # new shape (stretched to gs-multiple)
                    imgs = F.interpolate(imgs,
                                         size=ns,
                                         mode='bilinear',
                                         align_corners=False)

            # Autocast
            with amp.autocast(enabled=cuda):
                # Forward
                pred = model(imgs)

                # Loss
                loss, loss_items = compute_loss(pred, targets.to(device),
                                                model)  # scaled by batch_size
                if rank != -1:
                    loss *= opt.world_size  # gradient averaged between devices in DDP mode
                # if not torch.isfinite(loss):
                #     ('WARNING: non-finite loss, ending training ', loss_items)
                #     return results

            # Backward
            scaler.scale(loss).backward()

            # Optimize
            if ni % accumulate == 0:
                scaler.step(optimizer)  # optimizer.step
                scaler.update()
                optimizer.zero_grad()
                if ema is not None:
                    ema.update(model)

            # Print
            if rank in [-1, 0]:
                mloss = (mloss * i + loss_items) / (i + 1
                                                    )  # update mean losses
                mem = '%.3gG' % (torch.cuda.memory_reserved() / 1E9
                                 if torch.cuda.is_available() else 0)  # (GB)
                s = ('%10s' * 2 +
                     '%10.4g' * 6) % ('%g/%g' % (epoch, epochs - 1), mem,
                                      *mloss, targets.shape[0], imgs.shape[-1])
                pbar.set_description(s)

                # Plot
                if ni < 3:
                    f = str(log_dir / ('train_batch%g.jpg' % ni))  # filename
                    result = plot_images(images=imgs,
                                         targets=targets,
                                         paths=paths,
                                         fname=f)
                    if tb_writer and result is not None:
                        tb_writer.add_image(f,
                                            result,
                                            dataformats='HWC',
                                            global_step=epoch)
                        # tb_writer.add_graph(model, imgs)  # add model to tensorboard

            # end batch ------------------------------------------------------------------------------------------------

        # Scheduler
        scheduler.step()

        # DDP process 0 or single-GPU
        if rank in [-1, 0]:
            # mAP
            if ema is not None:
                ema.update_attr(model)
            final_epoch = epoch + 1 == epochs
            if not opt.notest or final_epoch:  # Calculate mAP
                # results, maps, times = test.test(opt.data,
                #                                  batch_size=batch_size,
                #                                  imgsz=imgsz,
                #                                  save_json=False,
                #                                  model=ema.ema.module if hasattr(ema.ema, 'module') else ema.ema,
                #                                  single_cls=opt.single_cls,
                #                                  dataloader=dataloader,
                #                                  save_dir=log_dir)
                results, maps, times = test.test(
                    opt.data,
                    batch_size=batch_size,
                    imgsz=imgsz_test,
                    save_json=final_epoch
                    and opt.data.endswith(os.sep + 'coco.yaml'),
                    model=ema.ema.module
                    if hasattr(ema.ema, 'module') else ema.ema,
                    single_cls=opt.single_cls,
                    dataloader=testloader,
                    save_dir=log_dir)

            # Write
            with open(results_file, 'a') as f:
                f.write(s + '%10.4g' * 7 % results +
                        '\n')  # P, R, mAP, F1, test_losses=(GIoU, obj, cls)
            if len(opt.name) and opt.bucket:
                os.system('gsutil cp %s gs://%s/results/results%s.txt' %
                          (results_file, opt.bucket, opt.name))

            # Tensorboard
            if tb_writer:
                tags = [
                    'train/giou_loss', 'train/obj_loss', 'train/cls_loss',
                    'metrics/precision', 'metrics/recall', 'metrics/mAP_0.5',
                    'metrics/mAP_0.5:0.95', 'val/giou_loss', 'val/obj_loss',
                    'val/cls_loss'
                ]
                for x, tag in zip(list(mloss[:-1]) + list(results), tags):
                    tb_writer.add_scalar(tag, x, epoch)

            # Update best mAP
            fi = fitness(np.array(results).reshape(
                1, -1))  # fitness_i = weighted combination of [P, R, mAP, F1]
            if fi > best_fitness:
                best_fitness = fi

            # Save model
            save = (not opt.nosave) or (final_epoch and not opt.evolve)
            if save:
                with open(results_file, 'r') as f:  # create checkpoint
                    ckpt = {
                        'epoch':
                        epoch,
                        'best_fitness':
                        best_fitness,
                        'training_results':
                        f.read(),
                        'model':
                        ema.ema.module.state_dict()
                        if hasattr(ema, 'module') else ema.ema.state_dict(),
                        'optimizer':
                        None if final_epoch else optimizer.state_dict()
                    }

                # Save last, best and delete
                torch.save(ckpt, last)
                if (epoch + 1) % 50 == 0:
                    torch.save(
                        ckpt, last.replace('last.pt',
                                           '{:03d}.pt'.format(epoch)))
                if (best_fitness == fi) and not final_epoch:
                    torch.save(ckpt, best)
                del ckpt
        # end epoch ----------------------------------------------------------------------------------------------------
    # end training

    if rank in [-1, 0]:
        # Strip optimizers
        n = ('_'
             if len(opt.name) and not opt.name.isnumeric() else '') + opt.name
        fresults, flast, fbest = 'results%s.txt' % n, wdir + 'last%s.pt' % n, wdir + 'best%s.pt' % n
        for f1, f2 in zip([wdir + 'last.pt', wdir + 'best.pt', 'results.txt'],
                          [flast, fbest, fresults]):
            if os.path.exists(f1):
                os.rename(f1, f2)  # rename
                ispt = f2.endswith('.pt')  # is *.pt
                strip_optimizer(f2) if ispt else None  # strip optimizer
                os.system('gsutil cp %s gs://%s/weights' % (
                    f2, opt.bucket)) if opt.bucket and ispt else None  # upload
        # Finish
        if not opt.evolve:
            plot_results(save_dir=log_dir)  # save as results.png
        print('%g epochs completed in %.3f hours.\n' %
              (epoch - start_epoch + 1, (time.time() - t0) / 3600))

    dist.destroy_process_group() if rank not in [-1, 0] else None
    torch.cuda.empty_cache()
    return results