# Copyright (c) Facebook, Inc. and its affiliates. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. import argparse import os import sys import datetime import time import math import json from pathlib import Path import numpy as np from PIL import Image import torch import torch.nn as nn import torch.distributed as dist import torch.backends.cudnn as cudnn import torch.nn.functional as F from torchvision import datasets, transforms from torchvision import models as torchvision_models import utils import vision_transformer as vits from vision_transformer import DINOHead torchvision_archs = sorted(name for name in torchvision_models.__dict__ if name.islower() and not name.startswith("__") and callable(torchvision_models.__dict__[name])) def get_args_parser(): parser = argparse.ArgumentParser('DINO', add_help=False) # Model parameters parser.add_argument('--arch', default='vit_small', type=str, choices=['vit_tiny', 'vit_small', 'vit_base', 'xcit', 'deit_tiny', 'deit_small'] \ + torchvision_archs + torch.hub.list("facebookresearch/xcit"), help="""Name of architecture to train. For quick experiments with ViTs, we recommend using vit_tiny or vit_small.""") parser.add_argument('--patch_size', default=16, type=int, help="""Size in pixels of input square patches - default 16 (for 16x16 patches). Using smaller values leads to better performance but requires more memory. Applies only for ViTs (vit_tiny, vit_small and vit_base). If <16, we recommend disabling mixed precision training (--use_fp16 false) to avoid unstabilities.""") parser.add_argument('--out_dim', default=65536, type=int, help="""Dimensionality of the DINO head output. For complex and large datasets large values (like 65k) work well.""") parser.add_argument('--norm_last_layer', default=True, type=utils.bool_flag, help="""Whether or not to weight normalize the last layer of the DINO head. Not normalizing leads to better performance but can make the training unstable. In our experiments, we typically set this paramater to False with vit_small and True with vit_base.""") parser.add_argument('--momentum_teacher', default=0.996, type=float, help="""Base EMA parameter for teacher update. The value is increased to 1 during training with cosine schedule. We recommend setting a higher value with small batches: for example use 0.9995 with batch size of 256.""") parser.add_argument('--use_bn_in_head', default=False, type=utils.bool_flag, help="Whether to use batch normalizations in projection head (Default: False)") # Temperature teacher parameters parser.add_argument('--warmup_teacher_temp', default=0.04, type=float, help="""Initial value for the teacher temperature: 0.04 works well in most cases. Try decreasing it if the training loss does not decrease.""") parser.add_argument('--teacher_temp', default=0.04, type=float, help="""Final value (after linear warmup) of the teacher temperature. For most experiments, anything above 0.07 is unstable. We recommend starting with the default value of 0.04 and increase this slightly if needed.""") parser.add_argument('--warmup_teacher_temp_epochs', default=0, type=int, help='Number of warmup epochs for the teacher temperature (Default: 30).') # Training/Optimization parameters parser.add_argument('--use_fp16', type=utils.bool_flag, default=True, help="""Whether or not to use half precision for training. Improves training time and memory requirements, but can provoke instability and slight decay of performance. We recommend disabling mixed precision if the loss is unstable, if reducing the patch size or if training with bigger ViTs.""") parser.add_argument('--weight_decay', type=float, default=0.04, help="""Initial value of the weight decay. With ViT, a smaller value at the beginning of training works well.""") parser.add_argument('--weight_decay_end', type=float, default=0.4, help="""Final value of the weight decay. We use a cosine schedule for WD and using a larger decay by the end of training improves performance for ViTs.""") parser.add_argument('--clip_grad', type=float, default=3.0, help="""Maximal parameter gradient norm if using gradient clipping. Clipping with norm .3 ~ 1.0 can help optimization for larger ViT architectures. 0 for disabling.""") parser.add_argument('--batch_size_per_gpu', default=64, type=int, help='Per-GPU batch-size : number of distinct images loaded on one GPU.') parser.add_argument('--epochs', default=100, type=int, help='Number of epochs of training.') parser.add_argument('--freeze_last_layer', default=1, type=int, help="""Number of epochs during which we keep the output layer fixed. Typically doing so during the first epoch helps training. Try increasing this value if the loss does not decrease.""") parser.add_argument("--lr", default=0.0005, type=float, help="""Learning rate at the end of linear warmup (highest LR used during training). The learning rate is linearly scaled with the batch size, and specified here for a reference batch size of 256.""") parser.add_argument("--warmup_epochs", default=10, type=int, help="Number of epochs for the linear learning-rate warm up.") parser.add_argument('--min_lr', type=float, default=1e-6, help="""Target LR at the end of optimization. We use a cosine LR schedule with linear warmup.""") parser.add_argument('--optimizer', default='adamw', type=str, choices=['adamw', 'sgd', 'lars'], help="""Type of optimizer. We recommend using adamw with ViTs.""") parser.add_argument('--drop_path_rate', type=float, default=0.1, help="stochastic depth rate") # Multi-crop parameters parser.add_argument('--global_crops_scale', type=float, nargs='+', default=(0.4, 1.), help="""Scale range of the cropped image before resizing, relatively to the origin image. Used for large global view cropping. When disabling multi-crop (--local_crops_number 0), we recommand using a wider range of scale ("--global_crops_scale 0.14 1." for example)""") parser.add_argument('--local_crops_number', type=int, default=8, help="""Number of small local views to generate. Set this parameter to 0 to disable multi-crop training. When disabling multi-crop we recommend to use "--global_crops_scale 0.14 1." """) parser.add_argument('--local_crops_scale', type=float, nargs='+', default=(0.05, 0.4), help="""Scale range of the cropped image before resizing, relatively to the origin image. Used for small local view cropping of multi-crop.""") # Misc parser.add_argument('--data_path', default='/path/to/imagenet/train/', type=str, help='Please specify path to the ImageNet training data.') parser.add_argument('--output_dir', default=".", type=str, help='Path to save logs and checkpoints.') parser.add_argument('--saveckp_freq', default=20, type=int, help='Save checkpoint every x epochs.') parser.add_argument('--seed', default=0, type=int, help='Random seed.') parser.add_argument('--num_workers', default=10, type=int, help='Number of data loading workers per GPU.') parser.add_argument("--dist_url", default="env://", type=str, help="""url used to set up distributed training; see https://pytorch.org/docs/stable/distributed.html""") parser.add_argument("--local_rank", default=0, type=int, help="Please ignore and do not set this argument.") return parser def train_dino(args): utils.init_distributed_mode(args) utils.fix_random_seeds(args.seed) print("git:\n {}\n".format(utils.get_sha())) print("\n".join("%s: %s" % (k, str(v)) for k, v in sorted(dict(vars(args)).items()))) cudnn.benchmark = True # ============ preparing data ... ============ transform = DataAugmentationDINO( args.global_crops_scale, args.local_crops_scale, args.local_crops_number, ) dataset = datasets.ImageFolder(args.data_path, transform=transform) sampler = torch.utils.data.DistributedSampler(dataset, shuffle=True) data_loader = torch.utils.data.DataLoader( dataset, sampler=sampler, batch_size=args.batch_size_per_gpu, num_workers=args.num_workers, pin_memory=True, drop_last=True, ) print(f"Data loaded: there are {len(dataset)} images.") # ============ building student and teacher networks ... ============ # we changed the name DeiT-S for ViT-S to avoid confusions args.arch = args.arch.replace("deit", "vit") # if the network is a Vision Transformer (i.e. vit_tiny, vit_small, vit_base) if args.arch in vits.__dict__.keys(): student = vits.__dict__[args.arch]( patch_size=args.patch_size, drop_path_rate=args.drop_path_rate, # stochastic depth ) teacher = vits.__dict__[args.arch](patch_size=args.patch_size) embed_dim = student.embed_dim # if the network is a XCiT elif args.arch in torch.hub.list("facebookresearch/xcit"): student = torch.hub.load('facebookresearch/xcit', args.arch, pretrained=False, drop_path_rate=args.drop_path_rate) teacher = torch.hub.load('facebookresearch/xcit', args.arch, pretrained=False) embed_dim = student.embed_dim # otherwise, we check if the architecture is in torchvision models elif args.arch in torchvision_models.__dict__.keys(): student = torchvision_models.__dict__[args.arch]() teacher = torchvision_models.__dict__[args.arch]() embed_dim = student.fc.weight.shape[1] else: print(f"Unknow architecture: {args.arch}") # multi-crop wrapper handles forward with inputs of different resolutions student = utils.MultiCropWrapper(student, DINOHead( embed_dim, args.out_dim, use_bn=args.use_bn_in_head, norm_last_layer=args.norm_last_layer, )) teacher = utils.MultiCropWrapper( teacher, DINOHead(embed_dim, args.out_dim, args.use_bn_in_head), ) # move networks to gpu student, teacher = student.cuda(), teacher.cuda() # synchronize batch norms (if any) if utils.has_batchnorms(student): student = nn.SyncBatchNorm.convert_sync_batchnorm(student) teacher = nn.SyncBatchNorm.convert_sync_batchnorm(teacher) # we need DDP wrapper to have synchro batch norms working... teacher = nn.parallel.DistributedDataParallel(teacher, device_ids=[args.gpu]) teacher_without_ddp = teacher.module else: # teacher_without_ddp and teacher are the same thing teacher_without_ddp = teacher student = nn.parallel.DistributedDataParallel(student, device_ids=[args.gpu]) # teacher and student start with the same weights teacher_without_ddp.load_state_dict(student.module.state_dict()) # there is no backpropagation through the teacher, so no need for gradients for p in teacher.parameters(): p.requires_grad = False print(f"Student and Teacher are built: they are both {args.arch} network.") # ============ preparing loss ... ============ dino_loss = DINOLoss( args.out_dim, args.local_crops_number + 2, # total number of crops = 2 global crops + local_crops_number args.warmup_teacher_temp, args.teacher_temp, args.warmup_teacher_temp_epochs, args.epochs, ).cuda() # ============ preparing optimizer ... ============ params_groups = utils.get_params_groups(student) if args.optimizer == "adamw": optimizer = torch.optim.AdamW(params_groups) # to use with ViTs elif args.optimizer == "sgd": optimizer = torch.optim.SGD(params_groups, lr=0, momentum=0.9) # lr is set by scheduler elif args.optimizer == "lars": optimizer = utils.LARS(params_groups) # to use with convnet and large batches # for mixed precision training fp16_scaler = None if args.use_fp16: fp16_scaler = torch.cuda.amp.GradScaler() # ============ init schedulers ... ============ lr_schedule = utils.cosine_scheduler( args.lr * (args.batch_size_per_gpu * utils.get_world_size()) / 256., # linear scaling rule args.min_lr, args.epochs, len(data_loader), warmup_epochs=args.warmup_epochs, ) wd_schedule = utils.cosine_scheduler( args.weight_decay, args.weight_decay_end, args.epochs, len(data_loader), ) # momentum parameter is increased to 1. during training with a cosine schedule momentum_schedule = utils.cosine_scheduler(args.momentum_teacher, 1, args.epochs, len(data_loader)) print(f"Loss, optimizer and schedulers ready.") # ============ optionally resume training ... ============ to_restore = {"epoch": 0} utils.restart_from_checkpoint( os.path.join(args.output_dir, "checkpoint.pth"), run_variables=to_restore, student=student, teacher=teacher, optimizer=optimizer, fp16_scaler=fp16_scaler, dino_loss=dino_loss, ) start_epoch = to_restore["epoch"] start_time = time.time() print("Starting DINO training !") for epoch in range(start_epoch, args.epochs): data_loader.sampler.set_epoch(epoch) # ============ training one epoch of DINO ... ============ train_stats = train_one_epoch(student, teacher, teacher_without_ddp, dino_loss, data_loader, optimizer, lr_schedule, wd_schedule, momentum_schedule, epoch, fp16_scaler, args) # ============ writing logs ... ============ save_dict = { 'student': student.state_dict(), 'teacher': teacher.state_dict(), 'optimizer': optimizer.state_dict(), 'epoch': epoch + 1, 'args': args, 'dino_loss': dino_loss.state_dict(), } if fp16_scaler is not None: save_dict['fp16_scaler'] = fp16_scaler.state_dict() utils.save_on_master(save_dict, os.path.join(args.output_dir, 'checkpoint.pth')) if args.saveckp_freq and epoch % args.saveckp_freq == 0: utils.save_on_master(save_dict, os.path.join(args.output_dir, f'checkpoint{epoch:04}.pth')) log_stats = {**{f'train_{k}': v for k, v in train_stats.items()}, 'epoch': epoch} if utils.is_main_process(): with (Path(args.output_dir) / "log.txt").open("a") as f: f.write(json.dumps(log_stats) + "\n") total_time = time.time() - start_time total_time_str = str(datetime.timedelta(seconds=int(total_time))) print('Training time {}'.format(total_time_str)) def train_one_epoch(student, teacher, teacher_without_ddp, dino_loss, data_loader, optimizer, lr_schedule, wd_schedule, momentum_schedule,epoch, fp16_scaler, args): metric_logger = utils.MetricLogger(delimiter=" ") header = 'Epoch: [{}/{}]'.format(epoch, args.epochs) for it, (images, _) in enumerate(metric_logger.log_every(data_loader, 10, header)): # update weight decay and learning rate according to their schedule it = len(data_loader) * epoch + it # global training iteration for i, param_group in enumerate(optimizer.param_groups): param_group["lr"] = lr_schedule[it] if i == 0: # only the first group is regularized param_group["weight_decay"] = wd_schedule[it] # move images to gpu images = [im.cuda(non_blocking=True) for im in images] # teacher and student forward passes + compute dino loss with torch.cuda.amp.autocast(fp16_scaler is not None): teacher_output = teacher(images[:2]) # only the 2 global views pass through the teacher student_output = student(images) loss = dino_loss(student_output, teacher_output, epoch) if not math.isfinite(loss.item()): print("Loss is {}, stopping training".format(loss.item()), force=True) sys.exit(1) # student update optimizer.zero_grad() param_norms = None if fp16_scaler is None: loss.backward() if args.clip_grad: param_norms = utils.clip_gradients(student, args.clip_grad) utils.cancel_gradients_last_layer(epoch, student, args.freeze_last_layer) optimizer.step() else: fp16_scaler.scale(loss).backward() if args.clip_grad: fp16_scaler.unscale_(optimizer) # unscale the gradients of optimizer's assigned params in-place param_norms = utils.clip_gradients(student, args.clip_grad) utils.cancel_gradients_last_layer(epoch, student, args.freeze_last_layer) fp16_scaler.step(optimizer) fp16_scaler.update() # EMA update for the teacher with torch.no_grad(): m = momentum_schedule[it] # momentum parameter for param_q, param_k in zip(student.module.parameters(), teacher_without_ddp.parameters()): param_k.data.mul_(m).add_((1 - m) * param_q.detach().data) # logging torch.cuda.synchronize() metric_logger.update(loss=loss.item()) metric_logger.update(lr=optimizer.param_groups[0]["lr"]) metric_logger.update(wd=optimizer.param_groups[0]["weight_decay"]) # gather the stats from all processes metric_logger.synchronize_between_processes() print("Averaged stats:", metric_logger) return {k: meter.global_avg for k, meter in metric_logger.meters.items()} class DINOLoss(nn.Module): def __init__(self, out_dim, ncrops, warmup_teacher_temp, teacher_temp, warmup_teacher_temp_epochs, nepochs, student_temp=0.1, center_momentum=0.9): super().__init__() self.student_temp = student_temp self.center_momentum = center_momentum self.ncrops = ncrops self.register_buffer("center", torch.zeros(1, out_dim)) # we apply a warm up for the teacher temperature because # a too high temperature makes the training instable at the beginning self.teacher_temp_schedule = np.concatenate(( np.linspace(warmup_teacher_temp, teacher_temp, warmup_teacher_temp_epochs), np.ones(nepochs - warmup_teacher_temp_epochs) * teacher_temp )) def forward(self, student_output, teacher_output, epoch): """ Cross-entropy between softmax outputs of the teacher and student networks. """ student_out = student_output / self.student_temp student_out = student_out.chunk(self.ncrops) # teacher centering and sharpening temp = self.teacher_temp_schedule[epoch] teacher_out = F.softmax((teacher_output - self.center) / temp, dim=-1) teacher_out = teacher_out.detach().chunk(2) total_loss = 0 n_loss_terms = 0 for iq, q in enumerate(teacher_out): for v in range(len(student_out)): if v == iq: # we skip cases where student and teacher operate on the same view continue loss = torch.sum(-q * F.log_softmax(student_out[v], dim=-1), dim=-1) total_loss += loss.mean() n_loss_terms += 1 total_loss /= n_loss_terms self.update_center(teacher_output) return total_loss @torch.no_grad() def update_center(self, teacher_output): """ Update center used for teacher output. """ batch_center = torch.sum(teacher_output, dim=0, keepdim=True) dist.all_reduce(batch_center) batch_center = batch_center / (len(teacher_output) * dist.get_world_size()) # ema update self.center = self.center * self.center_momentum + batch_center * (1 - self.center_momentum) class DataAugmentationDINO(object): def __init__(self, global_crops_scale, local_crops_scale, local_crops_number): flip_and_color_jitter = transforms.Compose([ transforms.RandomHorizontalFlip(p=0.5), transforms.RandomApply( [transforms.ColorJitter(brightness=0.4, contrast=0.4, saturation=0.2, hue=0.1)], p=0.8 ), transforms.RandomGrayscale(p=0.2), ]) normalize = transforms.Compose([ transforms.ToTensor(), transforms.Normalize((0.485, 0.456, 0.406), (0.229, 0.224, 0.225)), ]) # first global crop self.global_transfo1 = transforms.Compose([ transforms.RandomResizedCrop(224, scale=global_crops_scale, interpolation=Image.BICUBIC), flip_and_color_jitter, utils.GaussianBlur(1.0), normalize, ]) # second global crop self.global_transfo2 = transforms.Compose([ transforms.RandomResizedCrop(224, scale=global_crops_scale, interpolation=Image.BICUBIC), flip_and_color_jitter, utils.GaussianBlur(0.1), utils.Solarization(0.2), normalize, ]) # transformation for the local small crops self.local_crops_number = local_crops_number self.local_transfo = transforms.Compose([ transforms.RandomResizedCrop(96, scale=local_crops_scale, interpolation=Image.BICUBIC), flip_and_color_jitter, utils.GaussianBlur(p=0.5), normalize, ]) def __call__(self, image): crops = [] crops.append(self.global_transfo1(image)) crops.append(self.global_transfo2(image)) for _ in range(self.local_crops_number): crops.append(self.local_transfo(image)) return crops if __name__ == '__main__': parser = argparse.ArgumentParser('DINO', parents=[get_args_parser()]) args = parser.parse_args() Path(args.output_dir).mkdir(parents=True, exist_ok=True) train_dino(args)