Пример #1
0
 def on_train_batch_end(self, ni, model, imgs, targets, paths, plots):
     # Callback runs on train batch end
     if plots:
         if ni == 0:
             if self.tb and not self.opt.sync_bn:  # --sync known issue https://github.com/ultralytics/yolov5/issues/3754
                 with warnings.catch_warnings():
                     warnings.simplefilter(
                         'ignore')  # suppress jit trace warning
                     self.tb.add_graph(
                         torch.jit.trace(de_parallel(model),
                                         imgs[0:1],
                                         strict=False), [])
         if ni < 3:
             f = self.save_dir / f'train_batch{ni}.jpg'  # filename
             plot_images(imgs, targets, paths, f)
         if self.wandb and ni == 10:
             files = sorted(self.save_dir.glob('train*.jpg'))
             self.wandb.log({
                 'Mosaics': [
                     wandb.Image(str(f), caption=f.name) for f in files
                     if f.exists()
                 ]
             })
Пример #2
0
 def on_train_batch_end(self, ni, model, imgs, targets, paths, plots):
     # Callback runs on train batch end
     if plots:
         if ni == 0:
             with warnings.catch_warnings():
                 warnings.simplefilter(
                     'ignore')  # suppress jit trace warning
                 self.tb.add_graph(
                     torch.jit.trace(de_parallel(model),
                                     imgs[0:1],
                                     strict=False), [])
         if ni < 3:
             f = self.save_dir / f'train_batch{ni}.jpg'  # filename
             Thread(target=plot_images,
                    args=(imgs, targets, paths, f),
                    daemon=True).start()
         if self.wandb and ni == 10:
             files = sorted(self.save_dir.glob('train*.jpg'))
             self.wandb.log({
                 'Mosaics': [
                     wandb.Image(str(f), caption=f.name) for f in files
                     if f.exists()
                 ]
             })
Пример #3
0
def train(
        hyp,  # path/to/hyp.yaml or hyp dictionary
        opt,
        device,
        callbacks):
    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

    # 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  # 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
        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

    # 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']}")

    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 (no decay)
            g0.append(v.weight)
        elif hasattr(v, 'weight') and isinstance(
                v.weight, nn.Parameter):  # weight (with decay)
            g1.append(v.weight)

    if opt.optimizer == 'Adam':
        optimizer = Adam(g0, lr=hyp['lr0'],
                         betas=(hyp['momentum'],
                                0.999))  # adjust beta1 to momentum
    elif opt.optimizer == 'AdamW':
        optimizer = AdamW(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 (no decay), {len(g1)} weight, {len(g2)} bias")
    del g0, g1, g2

    # 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:
        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),
             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)
    stopper = EarlyStopping(patience=opt.patience)
    compute_loss = ComputeLoss(model)  # init loss class
    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 ------------------------------------------------------------------
        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 -------------------------------------------------------------
            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
                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]))
                callbacks.run('on_train_batch_end', ni, model, imgs, targets,
                              paths, plots, opt.sync_bn)
                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=True,
                        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)
        LOGGER.info(f"Results saved to {colorstr('bold', save_dir)}")

    torch.cuda.empty_cache()
    return results
Пример #4
0
def train(hyp,  # path/to/hyp.yaml or hyp dictionary
          opt,
          device,
          ):
    save_dir, epochs, batch_size, weights, single_cls, evolve, data, cfg, resume, notest, nosave, workers, = \
        opt.save_dir, opt.epochs, opt.batch_size, opt.weights, opt.single_cls, opt.evolve, opt.data, opt.cfg, \
        opt.resume, opt.notest, opt.nosave, opt.workers

    # Directories
    save_dir = Path(save_dir)
    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'

    # 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)

    # Configure
    plots = not evolve  # create plots
    cuda = device.type != 'cpu'
    init_seeds(2 + RANK)
    with open(data) as f:
        data_dict = yaml.safe_load(f)  # data dict

    # Loggers
    loggers = {'wandb': None, 'tb': None}  # loggers dict
    if RANK in [-1, 0]:
        # TensorBoard
        if not evolve:
            prefix = colorstr('tensorboard: ')
            logger.info(f"{prefix}Start with 'tensorboard --logdir {opt.project}', view at http://localhost:6006/")
            loggers['tb'] = SummaryWriter(str(save_dir))

        # W&B
        opt.hyp = hyp  # add hyperparameters
        run_id = torch.load(weights).get('wandb_id') if weights.endswith('.pt') and os.path.isfile(weights) else None
        run_id = run_id if opt.resume else None  # start fresh run if transfer learning
        wandb_logger = WandbLogger(opt, save_dir.stem, run_id, data_dict)
        loggers['wandb'] = wandb_logger.wandb
        if loggers['wandb']:
            data_dict = wandb_logger.data_dict
            weights, epochs, hyp = opt.weights, opt.epochs, opt.hyp  # may update weights, epochs if resuming

    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, '%g names found for nc=%g dataset in %s' % (len(names), nc, data)  # check
    is_coco = data.endswith('coco.yaml') and nc == 80  # COCO dataset

    # Model
    pretrained = weights.endswith('.pt')
    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
        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(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 / 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']}")

    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 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:
        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
    dataloader, 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(dataloader)  # number of batches
    assert mlc < nc, 'Label class %g exceeds nc=%g in %s. Possible class labels are 0-%g' % (mlc, nc, data, nc - 1)

    # Process 0
    if RANK in [-1, 0]:
        testloader = create_dataloader(test_path, imgsz_test, batch_size // WORLD_SIZE * 2, gs, single_cls,
                                       hyp=hyp, cache=opt.cache_images and not notest, 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)
                if loggers['tb']:
                    loggers['tb'].add_histogram('classes', c, 0)  # TensorBoard

            # 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.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', '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 / 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 *= 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) % (
                    f'{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 loggers['tb'] and ni == 0:  # TensorBoard
                        with warnings.catch_warnings():
                            warnings.simplefilter('ignore')  # suppress jit trace warning
                            loggers['tb'].add_graph(torch.jit.trace(de_parallel(model), imgs[0:1], strict=False), [])
                elif plots and ni == 10 and loggers['wandb']:
                    wandb_logger.log({'Mosaics': [loggers['wandb'].Image(str(x), caption=x.name) for x in
                                                  save_dir.glob('train*.jpg') if x.exists()]})

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

        # Scheduler
        lr = [x['lr'] for x in optimizer.param_groups]  # for loggers
        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 notest or final_epoch:  # Calculate mAP
                wandb_logger.current_epoch = epoch + 1
                results, maps, _ = test.run(data_dict,
                                            batch_size=batch_size // WORLD_SIZE * 2,
                                            imgsz=imgsz_test,
                                            model=ema.ema,
                                            single_cls=single_cls,
                                            dataloader=testloader,
                                            save_dir=save_dir,
                                            save_json=is_coco and final_epoch,
                                            verbose=nc < 50 and final_epoch,
                                            plots=plots and final_epoch,
                                            wandb_logger=wandb_logger,
                                            compute_loss=compute_loss)

            # Write
            with open(results_file, 'a') as f:
                f.write(s + '%10.4g' * 7 % results + '\n')  # append metrics, val_loss

            # 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 loggers['tb']:
                    loggers['tb'].add_scalar(tag, x, epoch)  # TensorBoard
                if loggers['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 nosave) or (final_epoch and not evolve):  # if save
                ckpt = {'epoch': epoch,
                        'best_fitness': best_fitness,
                        'training_results': results_file.read_text(),
                        'model': deepcopy(de_parallel(model)).half(),
                        'ema': deepcopy(ema.ema).half(),
                        'updates': ema.updates,
                        'optimizer': optimizer.state_dict(),
                        'wandb_id': wandb_logger.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)
                if loggers['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]:
        logger.info(f'{epoch - start_epoch + 1} epochs completed in {(time.time() - t0) / 3600:.3f} hours.\n')
        if plots:
            plot_results(save_dir=save_dir)  # save as results.png
            if loggers['wandb']:
                files = ['results.png', 'confusion_matrix.png', *[f'{x}_curve.png' for x in ('F1', 'PR', 'P', 'R')]]
                wandb_logger.log({"Results": [loggers['wandb'].Image(str(save_dir / f), caption=f) for f in files
                                              if (save_dir / f).exists()]})

        if not evolve:
            if is_coco:  # COCO dataset
                for m in [last, best] if best.exists() else [last]:  # speed, mAP tests
                    results, _, _ = test.run(data_dict,
                                             batch_size=batch_size // WORLD_SIZE * 2,
                                             imgsz=imgsz_test,
                                             conf_thres=0.001,
                                             iou_thres=0.7,
                                             model=attempt_load(m, device).half(),
                                             single_cls=single_cls,
                                             dataloader=testloader,
                                             save_dir=save_dir,
                                             save_json=True,
                                             plots=False)

            # Strip optimizers
            for f in last, best:
                if f.exists():
                    strip_optimizer(f)  # strip optimizers
            if loggers['wandb']:  # Log the stripped model
                loggers['wandb'].log_artifact(str(best if best.exists() else last), type='model',
                                              name='run_' + wandb_logger.wandb_run.id + '_model',
                                              aliases=['latest', 'best', 'stripped'])
        wandb_logger.finish_run()

    torch.cuda.empty_cache()
    return results
Пример #5
0
def train(opt, device):
    epochs, batch_size, noval, nosave, workers, freeze, = \
        opt.epochs, opt.batch_size, opt.noval, opt.nosave, opt.workers, opt.freeze

    d = datetime.datetime.now()
    run_id = '{:%Y-%m-%d__%H-%M-%S}'.format(d)
    save_dir = Path(opt.save_dir) / run_id

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

    # Get hyperparameter dict
    hyp, hyp_loss = get_hyperparameter_dict(opt.dataset_name, opt.hp_config)

    # 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)
    tb_writer = SummaryWriter(save_dir)
    opt.img_dir = Path(opt.img_dir)

    # Config
    cuda = device.type != 'cpu'
    init_seeds(1 + RANK)

    # Dataloaders
    dataset_kwargs = {}
    if opt.train_img_res:
        dataset_kwargs = {'img_size': opt.train_img_res}
    dataset_splits = get_data_splits_by_name(
        data_root=opt.img_dir,
        dataset_name=opt.dataset_name,
        model_name=opt.model_name,
        batch_size=batch_size,
        num_workers=workers,
        distributed=(cuda and RANK != -1),
        **dataset_kwargs
    )
    test_img_size = dataset_splits["test"].dataset._img_size
    train_img_size = dataset_splits["train"].dataset._img_size
    if opt.test_img_res:
        test_img_size = opt.test_img_res

    train_loader = dataset_splits["train"]
    dataset = train_loader.dataset
    nc = dataset.num_classes

    nb = len(train_loader)  # number of batches

    # Model
    model = create_model(
        model_name=opt.model_name,
        pretraining_dataset=opt.pretraining_source_dataset,
        pretrained=opt.pretrained,
        num_classes=nc,
        progress=True,
        device=device,
    )

    # Freeze
    freeze = [f'model.{x}.' for x in range(freeze)]  # 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):
            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 (no decay)
            g0.append(v.weight)
        elif hasattr(v, 'weight') and isinstance(v.weight, nn.Parameter):  # weight (with 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

    start_epoch, best_fitness = 0, 0.0

    # 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'])

    # 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()')

    # Process 0
    if RANK in [-1, 0]:
        # Anchors
        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['giou'] *= 3. / nl  # scale to layers
    hyp['box'] = hyp['giou']
    hyp['cls'] *= nc / 80. * 3. / nl  # scale to classes and layers
    hyp['obj'] *= (train_img_size / 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

    eval_function = get_eval_function(dataset_name=opt.dataset_name,
        model_name=opt.model_name)
    criterion = YoloV5Loss(
        model=model,
        num_classes=nc,
        device=device,
        hyp_cfg=hyp_loss,
    )

    if opt.eval_before_train:
        ap_dict = evaluate(model, eval_function, opt.dataset_name, opt.img_dir,
            nc, test_img_size, device)
        LOGGER.info(f'Eval metrics: {ap_dict}')

    # Start training
    t0 = time.time()
    nw = max(round(hyp['warmup_epochs'] * nb), 1000)  # number of warmup iterations, max(3 epochs, 1k iterations)
    last_opt_step = -1
    scheduler.last_epoch = start_epoch - 1  # do not move
    scaler = amp.GradScaler(enabled=cuda)
    stopper = EarlyStopping(patience=opt.patience)

    loss_giou_mean = AverageMeter()
    loss_conf_mean = AverageMeter()
    loss_cls_mean = AverageMeter()
    loss_mean = AverageMeter()

    LOGGER.info(f'Image sizes {train_img_size} train, {test_img_size} val\n'
                f'Using {train_loader.num_workers} 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
        model.train()

        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, labels_length, _) in pbar:  # batch
            ni = i + nb * epoch  # number integrated batches (since train start)
            imgs = imgs.to(device, non_blocking=True).float()

            # Warmup
            if ni <= nw:
                xi = [0, nw]  # x interp
                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(train_img_size * 0.5, train_img_size * 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_giou, loss_conf, loss_cls = criterion(
                       pred, targets, labels_length, imgs.shape[-1]
                )
                # Update running mean of tracked metrics
                loss_items = torch.tensor([loss_giou, loss_conf, loss_cls]).to(device)

                if RANK in (-1, 0):
                    loss_giou_mean.update(loss_giou, imgs.size(0))
                    loss_conf_mean.update(loss_conf, imgs.size(0))
                    loss_cls_mean.update(loss_cls, imgs.size(0))
                    loss_mean.update(loss, imgs.size(0))

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

            # 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]))
            # end batch

        # Scheduler
        scheduler.step()

        if RANK in [-1, 0]:
            for idx, param_group in enumerate(optimizer.param_groups):
                tb_writer.add_scalar(f'learning_rate/gr{idx}', param_group['lr'], epoch)
            tb_writer.add_scalar('train/giou_loss', loss_giou_mean.avg, epoch)
            tb_writer.add_scalar('train/conf_loss', loss_conf_mean.avg, epoch)
            tb_writer.add_scalar('train/cls_loss', loss_cls_mean.avg, epoch)
            tb_writer.add_scalar('train/loss', loss_mean.avg, epoch)

            # mAP
            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) and epoch % opt.eval_freq == 0:  # Calculate mAP
                ap_dict = evaluate(ema.ema, eval_function, opt.dataset_name, opt.img_dir,
                    nc, test_img_size, device)
                LOGGER.info(f'Eval metrics: {ap_dict}')
                tb_writer.add_scalar('eval/mAP', ap_dict['mAP'], epoch)
                for eval_key, eval_value in ap_dict.items():
                    if eval_key != 'mAP':
                        tb_writer.add_scalar(f'ap_per_class/{eval_key}', eval_value, epoch)

            # Update best mAP
            fi = ap_dict['mAP']
            if fi > best_fitness:
                best_fitness = fi

            # Save model
            if (not nosave) or final_epoch:  # 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()}

                # 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

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

        # 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}...')
                    ckpt = torch.load(f, map_location=device)
                    model = ckpt['ema' if ckpt.get('ema') else 'model']
                    model.float().eval()

                    ap_dict = evaluate(model, eval_function, opt.dataset_name, opt.img_dir,
                        nc, test_img_size, device)
                    LOGGER.info(f'Eval metrics: {ap_dict}')

        LOGGER.info(f"Results saved to {colorstr('bold', save_dir)}")

    torch.cuda.empty_cache()
Пример #6
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.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)

    # Configure
    plots = not opt.evolve  # create plots
    cuda = device.type != 'cpu'
    init_seeds(2 + rank)
    with open(opt.data) as f:
        data_dict = yaml.safe_load(f)  # data dict

    # 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, 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

    ## hyps : command line hyperparameters (overwrites hyp.yaml)
    hyps = None
    try:
        if opt.hyps is not None and len(opt.hyps) > 0:
            ## hyps should evaluate to a python dict()
            hyps = ast.literal_eval(opt.hyps)
            ## add hyps to hyp (overwrite)...
            for k, v in hyps.items():
                hyp[k] = v
    except:
        pfunc(f'ERROR: problem parsing hyps (hyperparameter string): {hyps}')

    # Print swagger job json string...
    if opt.job_str:
        pfunc(f'swagger job submitted:\n{opt.job_str}\n')

    # 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)
    if hyp.get('freeze'):  ## freeze backbone layers?
        N = int(hyp['freeze']) + 1
        freeze = ['model.%s.' % x for x in range(N)]
        logger.info('Freezing first {} layers of network'.format(N))
    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('freezing %s' % k)
            v.requires_grad = False

    # ## create separate testing model
    # test_model = Model(opt.cfg or ckpt['model'].yaml, ch=3, nc=nc, anchors=hyp.get('anchors')).to(device)  # create
    # for k, v in test_model.named_parameters():
    #     v.requires_grad = False  # freeze all layers

    # 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

    lr_epochs, init_epochs = epochs, 0
    if hyp.get('init_epochs'):
        init_epochs = hyp['init_epochs']
        lr_epochs += init_epochs
    if opt.linear_lr:
        lf = lambda x: (1 - x / (lr_epochs - 1)) * (1.0 - hyp['lrf']) + hyp[
            'lrf']  # linear
    else:
        lf = one_cycle(1, hyp['lrf'], lr_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

    # Fix 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

    # Fix Crop size
    if hyp.get('crop') and hyp['crop'] > 0:
        hyp['crop'] = check_img_size(hyp['crop'], gs)
        imgsz_test = hyp['crop']

    # DP mode
    if cuda and rank == -1 and torch.cuda.device_count() > 1:
        pfunc('DOING DATA PARALLEL MODE!!!!!!!!!!!')
        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()')

    # if rank in [-1, 0]:
    pfunc(
        f'RANK={rank} opt.world_size={opt.world_size} dist.get_rank()={dist.get_rank()} dist.get_world_size()={dist.get_world_size()}'
    )

    # Trainloader
    trainloader, dataset = create_dataloader(
        train_path,
        imgsz,
        batch_size,
        gs,
        opt,
        hyp=hyp,
        augment=True,
        cache=opt.cache_images,  # cache='disk',
        cache_efficient_sampling=True,
        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(trainloader)  # 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
    # test_batch_size = batch_size
    test_batch_size = 1  ## so test_batch_size-per-GPU = 1 (needed for DDP validation)
    testloader = create_dataloader(test_path,
                                   imgsz_test,
                                   test_batch_size,
                                   gs,
                                   opt,
                                   hyp=hyp,
                                   cache=opt.cache_images and not opt.notest,
                                   cache_efficient_sampling=True,
                                   drop_last=False,
                                   shuffle=False,
                                   rect=True,
                                   training=False,
                                   rank=rank,
                                   world_size=opt.world_size,
                                   workers=opt.workers,
                                   pad=0.5,
                                   prefix=colorstr('val: '))[0]
    # Process 0
    new_best_model = False
    if rank in [-1, 0]:
        # orig_testloader = create_dataloader(test_path, imgsz_test, test_batch_size, gs, opt,
        #                                     hyp=hyp, cache=opt.cache_images and not opt.notest, rect=True, rank=-1,
        #                                     world_size=opt.world_size, workers=opt.workers,
        #                                     # lazy_caching=True,
        #                                     pad=0.5, prefix=colorstr('val: '))[0]

        if not opt.resume:
            labels = np.concatenate(dataset.labels, 0)
            c = torch.tensor(labels[:, 0])  # classes
            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 = t1 = 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

    ###### resuming training run..... #########################################
    if init_epochs > 0:
        nw = -1
        logger.info(
            'Stepping lr_scheduler forward {} epochs...'.format(init_epochs))
    for i in range(init_epochs - 1):
        scheduler.step()
    ## check initial model performance....
    # if init_epochs>0 and rank in [-1, 0]:
    #     test.test(opt.data,
    #             batch_size=test_batch_size,
    #             imgsz=imgsz_test,
    #             model=ema.ema,
    #             single_cls=opt.single_cls,
    #             dataloader=orig_testloader,
    #             save_dir=save_dir,
    #             verbose=True,
    #             plots=False,
    #             log_imgs=opt.log_imgs if wandb else 0,
    #             compute_loss=compute_loss)
    ###########################################################################

    pfunc(f'Image sizes {imgsz} train, {imgsz_test} test\n'
          f'Using {trainloader.num_workers} trainloader 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:
            trainloader.sampler.set_epoch(epoch)
        pbar = enumerate(trainloader)

        if rank in [-1, 0]:
            t1 = time.time()
            num_img = 0
            steps = list(range(100, 0, -2))
            pfunc(
                '=========================================================================================================='
            )
            pfunc(f'Epoch {epoch+1}/{epochs}')

        optimizer.zero_grad()

        # logging.StreamHandler.terminator = ""
        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

            ## simple progress indicator....
            if rank in [-1, 0]:
                prog = int(np.ceil(100 * (i + 1) / nb))
                while len(steps) > 0 and prog >= steps[-1]:
                    step = steps.pop()
                    # pfunc('.')
                    if step % 10 == 0:
                        pfunc(f'      {step}%')
                        # gpu_stats()

            # 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]:
                td = time.time() - t1
                num_img += imgs.shape[0]
                imgs_sec = (num_img / td) * opt.world_size
                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)

                # Plot
                if plots and ni < 5:
                    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_graph(torch.jit.trace(de_parallel(model), imgs, strict=False), [])  # model graph
                    #     # tb_writer.add_image(f, result, dataformats='HWC', global_step=epoch)
                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()

        # logging.StreamHandler.terminator = "\n"
        if rank in [-1, 0]:
            pfunc(
                ('     ' + '%10s' * 3) % ('total_min', 'gpu_mem', 'imgs_sec'))
            pfunc(('     ' + '%10.2f' + '%10s' + '%10.4g') %
                  (((time.time() - t1) / 60), mem, imgs_sec))
            t1 = time.time()
            final_epoch = epoch + 1 == epochs

        ##################################################################################
        ## DDP VALIDATION....
        # results = (mp, mr, mf1, map50, map)#, *(loss.cpu() / len(dataloader)).tolist())
        try:
            results = test_ddp(
                opt,
                de_parallel(model),
                testloader,
                rank,
                device,
                names,
            )

            if rank in [-1, 0]:
                pfunc(f'Validation Time: {(time.time()-t1)/60:0.2f} min')

                # Logging
                tags = [
                    'train/box_loss',
                    'train/obj_loss',
                    'train/cls_loss',  # train loss
                    'metrics/precision',
                    'metrics/recall',
                    'metrics/F1',
                    '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 fitness
                # fitness = weighted combination of [P, R, F1, [email protected], [email protected]:0.95]
                fi = fitness(np.array(results).reshape(1, -1))
                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(de_parallel(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 best_fitness == fi:
                        pfunc('Saving best model!')
                        torch.save(ckpt, best)
                        new_best_model = True
                        best_model_msg = f'Best Model: Epoch {epoch+1}, mF1={results[2]:0.3f}, [email protected]:0.95={results[4]:0.3f}'

                    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

                # Upload best model to s3
                if (epoch + 1) % 10 == 0 and epoch > 15:
                    if new_best_model:
                        strip_optimizer(best)
                        upload_model(opt)
                        new_best_model = False

                # print best model so far
                pfunc(best_model_msg)

                # Upload output log to s3
                upload_log(opt)

        ## END DDP VALIDATION
        except Exception as e:
            pfunc('Validation failed.')
        ################################################################

        # 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
        # pfunc('%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 [best] if best.exists() else [last]:  # speed, mAP tests
        #     results, _, _ = test.test(data_dict,
        #                                 batch_size=test_batch_size,
        #                                 imgsz=imgsz_test,
        #                                 model=attempt_load(m, device),#.half(),
        #                                 single_cls=opt.single_cls,
        #                                 dataloader=orig_testloader,
        #                                 save_dir=save_dir,
        #                                 # verbose=nc < 50 and final_epoch,
        #                                 # plots=plots and final_epoch,
        #                                 wandb_logger=wandb_logger,
        #                                 plots=False,
        #                                 # compute_loss=compute_loss,
        #                                 )

        # ## 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=['latest', 'best', 'stripped'])

        wandb_logger.finish_run()
    else:
        dist.destroy_process_group()
    torch.cuda.empty_cache()
    return results