main.py

#!/usr/bin/env python3
""" ImageNet Training Script

This is intended to be a lean and easily modifiable ImageNet training script that reproduces ImageNet
training results with some of the latest networks and training techniques. It favours canonical PyTorch
and standard Python style over trying to be able to 'do it all.' That said, it offers quite a few speed
and training result improvements over the usual PyTorch example scripts. Repurpose as you see fit.

This script was started from an early version of the PyTorch ImageNet example
(https://github.com/pytorch/examples/tree/master/imagenet)

NVIDIA CUDA specific speedups adopted from NVIDIA Apex examples
(https://github.com/NVIDIA/apex/tree/master/examples/imagenet)

Hacked together by / Copyright 2020 Ross Wightman (https://github.com/rwightman)
"""
import logging
import os
import shutil

from contextlib import suppress
from datetime import datetime
from functools import partial

import torch
import torch.nn as nn
from torch.nn.parallel import DistributedDataParallel as NativeDDP

from timm import utils
from timm.data import create_loader, resolve_data_config, Mixup, FastCollateMixup, AugMixDataset
from timm.layers import convert_splitbn_model, convert_sync_batchnorm, set_fast_norm
from timm.loss import JsdCrossEntropy, SoftTargetCrossEntropy, BinaryCrossEntropy, LabelSmoothingCrossEntropy
from timm.models import create_model, safe_model_name, resume_checkpoint, load_checkpoint
from timm.optim import create_optimizer_v2, optimizer_kwargs
from timm.scheduler import create_scheduler_v2, scheduler_kwargs
from timm.utils import ApexScaler, NativeScaler

from engine import train_one_epoch, validate
from models import *
from data import create_dataset

import torchstat, torchinfo, torchsummary
from calflops import calculate_flops

from utils.parser import _parse_args

try:
    from apex import amp
    from apex.parallel import DistributedDataParallel as ApexDDP
    from apex.parallel import convert_syncbn_model
    has_apex = True
except ImportError:
    has_apex = False

has_native_amp = False
try:
    if getattr(torch.cuda.amp, 'autocast') is not None:
        has_native_amp = True
except AttributeError:
    pass

try:
    import wandb
    has_wandb = True
except ImportError:
    has_wandb = False

try:
    from functorch.compile import memory_efficient_fusion
    has_functorch = True
except ImportError as e:
    has_functorch = False

has_compile = hasattr(torch, 'compile')


_logger = logging.getLogger('train')


def main():

# region Initial
    args, args_text = _parse_args()

    if torch.cuda.is_available():
        torch.backends.cuda.matmul.allow_tf32 = True
        torch.backends.cudnn.benchmark = True
    device = utils.init_distributed_device(args)
    
    # <<<------modified
    output_dir = None
    log_dir = None
    if utils.is_primary(args):
        model_name = "_".join([safe_model_name(args.model), str(args.img_size)])
        if args.output != None:
            args.output = os.path.join(args.output, model_name)

        if args.experiment:
            exp_name = args.experiment
        else:
            exp_name = '-'.join([
                datetime.now().strftime("%Y%m%d-%H%M%S"),
                safe_model_name(args.model),
                str(data_config['input_size'][-1])
            ])


        output_dir = utils.get_outdir(args.output if args.output else './output/train', exp_name, inc=not args.override)
        if args.override:
            shutil.rmtree(output_dir)
            os.makedirs(output_dir)
        log_dir = os.path.join(output_dir, "train_log.txt")

    # modified ------>>>
    
    utils.setup_default_logging(log_path=log_dir)

    args.prefetcher = not args.no_prefetcher
    args.grad_accum_steps = max(1, args.grad_accum_steps)


    if args.distributed:
        _logger.info(
            'Training in distributed mode with multiple processes, 1 device per process.'
            f'Process {args.rank}, total {args.world_size}, device {args.device}.')
    else:
        _logger.info(f'Training with a single process on 1 device ({args.device}).')
    assert args.rank >= 0

    # resolve AMP arguments based on PyTorch / Apex availability
    use_amp = None
    amp_dtype = torch.float16
    if args.amp:
        if args.amp_impl == 'apex':
            assert has_apex, 'AMP impl specified as APEX but APEX is not installed.'
            use_amp = 'apex'
            assert args.amp_dtype == 'float16'
        else:
            assert has_native_amp, 'Please update PyTorch to a version with native AMP (or use APEX).'
            use_amp = 'native'
            assert args.amp_dtype in ('float16', 'bfloat16')
        if args.amp_dtype == 'bfloat16':
            amp_dtype = torch.bfloat16

    utils.random_seed(args.seed, args.rank)

    if args.fuser:
        utils.set_jit_fuser(args.fuser)
    if args.fast_norm:
        set_fast_norm()

    in_chans = 3
    if args.in_chans is not None:
        in_chans = args.in_chans
    elif args.input_size is not None:
        in_chans = args.input_size[0]

    # <<<------ modified
    if args.use_deterministic:
        torch.manual_seed(0)
        if torch.cuda.is_available():
            torch.cuda.manual_seed_all(0)
            torch.backends.cudnn.deterministic = True
        utils.random_seed(0)
    # modified ------>>>
        
# endregion

# region Model
    model = create_model(
        args.model,
        pretrained=args.pretrained,
        in_chans=in_chans,
        num_classes=args.num_classes,
        drop_rate=args.drop,
        drop_path_rate=args.drop_path,
        drop_block_rate=args.drop_block,
        global_pool=args.gp,
        bn_momentum=args.bn_momentum,
        bn_eps=args.bn_eps,
        scriptable=args.torchscript,
        checkpoint_path=args.initial_checkpoint,
        **args.model_kwargs,
    )
    if args.head_init_scale is not None:
        with torch.no_grad():
            model.get_classifier().weight.mul_(args.head_init_scale)
            model.get_classifier().bias.mul_(args.head_init_scale)
    if args.head_init_bias is not None:
        nn.init.constant_(model.get_classifier().bias, args.head_init_bias)

    if args.num_classes is None:
        assert hasattr(model, 'num_classes'), 'Model must have `num_classes` attr if not set on cmd line/config.'
        args.num_classes = model.num_classes  # FIXME handle model default vs config num_classes more elegantly

    if args.grad_checkpointing:
        model.set_grad_checkpointing(enable=True)

    if utils.is_primary(args):
        _logger.info(
            f'Model {safe_model_name(args.model)} created, param count:{sum([m.numel() for m in model.parameters()])}')

    data_config = resolve_data_config(vars(args), model=model, verbose=utils.is_primary(args))

    # setup augmentation batch splits for contrastive loss or split bn
    num_aug_splits = 0
    if args.aug_splits > 0:
        assert args.aug_splits > 1, 'A split of 1 makes no sense'
        num_aug_splits = args.aug_splits
    
    # enable split bn (separate bn stats per batch-portion)
    if args.split_bn:
        assert num_aug_splits > 1 or args.resplit
        model = convert_splitbn_model(model, max(num_aug_splits, 2))

    # move model to GPU, enable channels last layout if set
    model.to(device=device)
    if args.channels_last:
        model.to(memory_format=torch.channels_last)

    # setup synchronized BatchNorm for distributed training
    if args.distributed and args.sync_bn:
        args.dist_bn = ''  # disable dist_bn when sync BN active
        assert not args.split_bn
        if has_apex and use_amp == 'apex':
            # Apex SyncBN used with Apex AMP
            # WARNING this won't currently work with models using BatchNormAct2d
            model = convert_syncbn_model(model)
        else:
            model = convert_sync_batchnorm(model)
        if utils.is_primary(args):
            _logger.info(
                'Converted model to use Synchronized BatchNorm. WARNING: You may have issues if using '
                'zero initialized BN layers (enabled by default for ResNets) while sync-bn enabled.')

    if args.torchscript:
        assert not args.torchcompile
        assert not use_amp == 'apex', 'Cannot use APEX AMP with torchscripted model'
        assert not args.sync_bn, 'Cannot use SyncBatchNorm with torchscripted model'
        model = torch.jit.script(model)
# endregion

# region Optimizer
    if not args.lr:
        global_batch_size = args.batch_size * args.world_size * args.grad_accum_steps
        batch_ratio = global_batch_size / args.lr_base_size
        if not args.lr_base_scale:
            on = args.opt.lower()
            args.lr_base_scale = 'sqrt' if any([o in on for o in ('ada', 'lamb')]) else 'linear'
        if args.lr_base_scale == 'sqrt':
            batch_ratio = batch_ratio ** 0.5
        args.lr = args.lr_base * batch_ratio
        if utils.is_primary(args):
            _logger.info(
                f'Learning rate ({args.lr}) calculated from base learning rate ({args.lr_base}) '
                f'and effective global batch size ({global_batch_size}) with {args.lr_base_scale} scaling.')

    optimizer = create_optimizer_v2(
        model,
        **optimizer_kwargs(cfg=args),
        **args.opt_kwargs,
    )
    # <<<------ modified
    if args.auto_scale_warmup_min_lr:
        args.warmup_lr = args.warmup_lr * batch_ratio
        args.min_lr = args.min_lr * batch_ratio
    # modifed ------>>>
    
# endregion

# region AMP on Loss & Optimizer
    # setup automatic mixed-precision (AMP) loss scaling and op casting
    amp_autocast = suppress  # do nothing
    loss_scaler = None
    if use_amp == 'apex':
        assert device.type == 'cuda'
        model, optimizer = amp.initialize(model, optimizer, opt_level='O1')
        loss_scaler = ApexScaler()
        if utils.is_primary(args):
            _logger.info('Using NVIDIA APEX AMP. Training in mixed precision.')
    elif use_amp == 'native':
        try:
            amp_autocast = partial(torch.autocast, device_type=device.type, dtype=amp_dtype)
        except (AttributeError, TypeError):
            # fallback to CUDA only AMP for PyTorch < 1.10
            assert device.type == 'cuda'
            amp_autocast = torch.cuda.amp.autocast
        if device.type == 'cuda' and amp_dtype == torch.float16:
            # loss scaler only used for float16 (half) dtype, bfloat16 does not need it
            loss_scaler = NativeScaler()
        if utils.is_primary(args):
            _logger.info('Using native Torch AMP. Training in mixed precision.')
    else:
        if utils.is_primary(args):
            _logger.info('AMP not enabled. Training in float32.')
# endregion

# region Resume
    # optionally resume from a checkpoint
    resume_epoch = None
    if args.resume:
        resume_epoch = resume_checkpoint(
            model,
            args.resume,
            optimizer=None if args.no_resume_opt else optimizer,
            loss_scaler=None if args.no_resume_opt else loss_scaler,
            log_info=utils.is_primary(args),
        )
# endregion

# region EMA
    # setup exponential moving average of model weights, SWA could be used here too
    model_ema = None
    if args.model_ema:
        # Important to create EMA model after cuda(), DP wrapper, and AMP but before DDP wrapper
        model_ema = utils.ModelEmaV2(
            model, decay=args.model_ema_decay, device='cpu' if args.model_ema_force_cpu else None)
        if args.resume:
            load_checkpoint(model_ema.module, args.resume, use_ema=True)
# endregion

# region Distributed
    # setup distributed training
    if args.distributed:
        if has_apex and use_amp == 'apex':
            # Apex DDP preferred unless native amp is activated
            if utils.is_primary(args):
                _logger.info("Using NVIDIA APEX DistributedDataParallel.")
            model = ApexDDP(model, delay_allreduce=True)
        else:
            if utils.is_primary(args):
                _logger.info("Using native Torch DistributedDataParallel.")
            model = NativeDDP(model, device_ids=[device], broadcast_buffers=not args.no_ddp_bb, find_unused_parameters=False)
        # NOTE: EMA model does not need to be wrapped by DDP

    if args.torchcompile:
        # torch compile should be done after DDP
        assert has_compile, 'A version of torch w/ torch.compile() is required for --compile, possibly a nightly.'
        model = torch.compile(model, backend=args.torchcompile)
# endregion

# region Dataset
    # create the train and eval datasets
    if args.data and not args.data_dir:
        args.data_dir = args.data
    dataset_train = create_dataset(
        args.dataset,
        root=args.data_dir,
        split=args.train_split,
        is_training=True,
        class_map=args.class_map,
        download=args.dataset_download,
        batch_size=args.batch_size,
        seed=args.seed,
        repeats=args.epoch_repeats,
    )

    dataset_eval = create_dataset(
        args.dataset,
        root=args.data_dir,
        split=args.val_split,
        is_training=False,
        class_map=args.class_map,
        download=args.dataset_download,
        batch_size=args.batch_size,
    )
# endregion

# region Dataloader
    # setup mixup / cutmix
    collate_fn = None
    mixup_fn = None
    mixup_active = args.mixup > 0 or args.cutmix > 0. or args.cutmix_minmax is not None
    if mixup_active:
        mixup_args = dict(
            mixup_alpha=args.mixup,
            cutmix_alpha=args.cutmix,
            cutmix_minmax=args.cutmix_minmax,
            prob=args.mixup_prob,
            switch_prob=args.mixup_switch_prob,
            mode=args.mixup_mode,
            label_smoothing=args.smoothing,
            num_classes=args.num_classes
        )
        if args.prefetcher:
            assert not num_aug_splits  # collate conflict (need to support deinterleaving in collate mixup)
            collate_fn = FastCollateMixup(**mixup_args)
        else:
            mixup_fn = Mixup(**mixup_args)

    # wrap dataset in AugMix helper
    if num_aug_splits > 1:
        dataset_train = AugMixDataset(dataset_train, num_splits=num_aug_splits)

    # create data loaders w/ augmentation pipeiine
    train_interpolation = args.train_interpolation
    if args.no_aug or not train_interpolation:
        train_interpolation = data_config['interpolation']
    loader_train = create_loader(
        dataset_train,
        input_size=data_config['input_size'],
        batch_size=args.batch_size,
        is_training=True,
        use_prefetcher=args.prefetcher,
        no_aug=args.no_aug,
        re_prob=args.reprob,
        re_mode=args.remode,
        re_count=args.recount,
        re_split=args.resplit,
        scale=args.scale,
        ratio=args.ratio,
        hflip=args.hflip,
        vflip=args.vflip,
        color_jitter=args.color_jitter,
        auto_augment=args.aa,
        num_aug_repeats=args.aug_repeats,
        num_aug_splits=num_aug_splits,
        interpolation=train_interpolation,
        mean=data_config['mean'],
        std=data_config['std'],
        num_workers=args.workers,
        distributed=args.distributed,
        collate_fn=collate_fn,
        pin_memory=args.pin_mem,
        device=device,
        use_multi_epochs_loader=args.use_multi_epochs_loader,
        worker_seeding=args.worker_seeding,
    )

    eval_workers = args.workers
    if args.distributed and ('tfds' in args.dataset or 'wds' in args.dataset):
        # FIXME reduces validation padding issues when using TFDS, WDS w/ workers and distributed training
        eval_workers = min(2, args.workers)
    loader_eval = create_loader(
        dataset_eval,
        input_size=data_config['input_size'],
        batch_size=args.validation_batch_size or args.batch_size,
        is_training=False,
        use_prefetcher=args.prefetcher,
        interpolation=data_config['interpolation'],
        mean=data_config['mean'],
        std=data_config['std'],
        num_workers=eval_workers,
        distributed=args.distributed,
        crop_pct=data_config['crop_pct'],
        pin_memory=args.pin_mem,
        device=device,
    )
# endregion

# region Loss
    # setup loss function
    if args.jsd_loss:
        assert num_aug_splits > 1  # JSD only valid with aug splits set
        train_loss_fn = JsdCrossEntropy(num_splits=num_aug_splits, smoothing=args.smoothing)
    elif mixup_active:
        # smoothing is handled with mixup target transform which outputs sparse, soft targets
        if args.bce_loss:
            train_loss_fn = BinaryCrossEntropy(target_threshold=args.bce_target_thresh)
        else:
            train_loss_fn = SoftTargetCrossEntropy()
    elif args.smoothing:
        if args.bce_loss:
            train_loss_fn = BinaryCrossEntropy(smoothing=args.smoothing, target_threshold=args.bce_target_thresh)
        else:
            train_loss_fn = LabelSmoothingCrossEntropy(smoothing=args.smoothing)
    else:
        train_loss_fn = nn.CrossEntropyLoss()
    train_loss_fn = train_loss_fn.to(device=device)
    validate_loss_fn = nn.CrossEntropyLoss().to(device=device)
# endregion

# region Checkpoint
    # setup checkpoint saver and eval metric tracking
    eval_metric = args.eval_metric
    best_metric = None
    best_epoch = None
    saver = None
    output_dir = None
    if utils.is_primary(args):
        if args.experiment:
            exp_name = args.experiment
        else:
            exp_name = '-'.join([
                datetime.now().strftime("%Y%m%d-%H%M%S"),
                safe_model_name(args.model),
                str(data_config['input_size'][-1])
            ])
        output_dir = utils.get_outdir(args.output if args.output else './output/train', exp_name)
        decreasing = True if eval_metric == 'loss' else False
        saver = utils.CheckpointSaver(
            model=model,
            optimizer=optimizer,
            args=args,
            model_ema=model_ema,
            amp_scaler=loss_scaler,
            checkpoint_dir=output_dir,
            recovery_dir=output_dir,
            decreasing=decreasing,
            max_history=args.checkpoint_hist
        )
        with open(os.path.join(output_dir, 'args.yaml'), 'w') as f:
            f.write(args_text)

    if utils.is_primary(args) and args.log_wandb:
        if has_wandb:
            wandb.init(project=args.experiment, config=args)
        else:
            _logger.warning(
                "You've requested to log metrics to wandb but package not found. "
                "Metrics not being logged to wandb, try `pip install wandb`")
# endregion

# region LR_Scheduler
    # setup learning rate schedule and starting epoch
    updates_per_epoch = (len(loader_train) + args.grad_accum_steps - 1) // args.grad_accum_steps
    lr_scheduler, num_epochs = create_scheduler_v2(
        optimizer,
        **scheduler_kwargs(args),
        updates_per_epoch=updates_per_epoch,
    )
    start_epoch = 0
    if args.start_epoch is not None:
        # a specified start_epoch will always override the resume epoch
        start_epoch = args.start_epoch
    elif resume_epoch is not None:
        start_epoch = resume_epoch
    if lr_scheduler is not None and start_epoch > 0:
        if args.sched_on_updates:
            lr_scheduler.step_update(start_epoch * updates_per_epoch)
        else:
            lr_scheduler.step(start_epoch)

    if utils.is_primary(args):
        _logger.info(
            f'Scheduled epochs: {num_epochs}. LR stepped per {"epoch" if lr_scheduler.t_in_epochs else "update"}.')
# endregion

# region Summary

    # <<<------ modified
    if args.summary != None:
        batch_size, img_size = args.batch_size, args.img_size
        if utils.is_primary(args):
            if args.summary == "torchstat":
                torchstat.stat(model, (3, img_size, img_size))
            if args.summary == "torchinfo":
                model_stats = str(torchinfo.summary(model, (1 ,3, img_size, img_size),depth=3,device=device,verbose=1))
                _logger.info(f'Model:\n {model_stats}')
            if args.summary == "torchsummary":
                model_stats = torchsummary.summary(model, (3, img_size, img_size), 1, device=device)
                _logger.info(f'Model:\n {model_stats}')
    
    if args.benchmark != None:
        batch_size, img_size = args.batch_size, args.img_size
        if utils.is_primary(args):
            if args.benchmark == "calflops":
                flops, macs, params = calculate_flops(model, (1 ,3, img_size, img_size), output_as_string=True, output_precision=4)
                _logger.info(
                    f"FLOPs:{flops}   MACs:{macs}   Params:{params}")

    # modified ------>>>

# endregion

    try:
        for epoch in range(start_epoch, num_epochs):
            if hasattr(dataset_train, 'set_epoch'):
                dataset_train.set_epoch(epoch)
            elif args.distributed and hasattr(loader_train.sampler, 'set_epoch'):
                loader_train.sampler.set_epoch(epoch)

            train_metrics = train_one_epoch(
                epoch,
                model,
                loader_train,
                optimizer,
                train_loss_fn,
                args,
                lr_scheduler=lr_scheduler,
                saver=saver,
                output_dir=output_dir,
                amp_autocast=amp_autocast,
                loss_scaler=loss_scaler,
                model_ema=model_ema,
                mixup_fn=mixup_fn,
                _logger=_logger,
            )

            if args.distributed and args.dist_bn in ('broadcast', 'reduce'):
                if utils.is_primary(args):
                    _logger.info("Distributing BatchNorm running means and vars")
                utils.distribute_bn(model, args.world_size, args.dist_bn == 'reduce')

            eval_metrics = validate(
                model,
                loader_eval,
                validate_loss_fn,
                args,
                amp_autocast=amp_autocast,
                _logger=_logger,
            )

            if model_ema is not None and not args.model_ema_force_cpu:
                if args.distributed and args.dist_bn in ('broadcast', 'reduce'):
                    utils.distribute_bn(model_ema, args.world_size, args.dist_bn == 'reduce')

                ema_eval_metrics = validate(
                    model_ema.module,
                    loader_eval,
                    validate_loss_fn,
                    args,
                    amp_autocast=amp_autocast,
                    log_suffix=' (EMA)',
                    _logger=_logger,
                )
                eval_metrics = ema_eval_metrics

            if output_dir is not None:
                lrs = [param_group['lr'] for param_group in optimizer.param_groups]
                utils.update_summary(
                    epoch,
                    train_metrics,
                    eval_metrics,
                    filename=os.path.join(output_dir, 'summary.csv'),
                    lr=sum(lrs) / len(lrs),
                    write_header=best_metric is None,
                    log_wandb=args.log_wandb and has_wandb,
                )

            if saver is not None:
                # save proper checkpoint with eval metric
                save_metric = eval_metrics[eval_metric]
                best_metric, best_epoch = saver.save_checkpoint(epoch, metric=save_metric)

            if lr_scheduler is not None:
                # step LR for next epoch
                lr_scheduler.step(epoch + 1, eval_metrics[eval_metric])

    except KeyboardInterrupt:
        pass

    if best_metric is not None:
        _logger.info('*** Best metric: {0} (epoch {1})'.format(best_metric, best_epoch))




if __name__ == '__main__':
    main()