utils.py

# --------------------------------------------------------
# Swin Transformer
# Copyright (c) 2021 Microsoft
# Licensed under The MIT License [see LICENSE for details]
# Written by Ze Liu
# --------------------------------------------------------

import os
import torch
import torch.distributed as dist
import torch.nn as nn
from torch._six import inf

try:
    # noinspection PyUnresolvedReferences
    from apex import amp
except ImportError:
    amp = None

def get_grad_norm_(parameters, norm_type: float = 2.0) -> torch.Tensor:
    if isinstance(parameters, torch.Tensor):
        parameters = [parameters]
    parameters = [p for p in parameters if p.grad is not None]
    norm_type = float(norm_type)
    if len(parameters) == 0:
        return torch.tensor(0.)
    device = parameters[0].grad.device
    if norm_type == inf:
        total_norm = max(p.grad.detach().abs().max().to(device) for p in parameters)
    else:
        total_norm = torch.norm(torch.stack([torch.norm(p.grad.detach(), norm_type).to(device) for p in parameters]), norm_type)
    return total_norm


class NativeScalerWithGradNormCount:
    state_dict_key = "amp_scaler"

    def __init__(self):
        self._scaler = torch.cuda.amp.GradScaler()

    def __call__(self, loss, optimizer, clip_grad=None, parameters=None, create_graph=False, update_grad=True):
        self._scaler.scale(loss).backward(create_graph=create_graph)
        if update_grad:
            if clip_grad is not None:
                assert parameters is not None
                self._scaler.unscale_(optimizer)  # unscale the gradients of optimizer's assigned params in-place
                norm = torch.nn.utils.clip_grad_norm_(parameters, clip_grad)
            else:
                self._scaler.unscale_(optimizer)
                norm = get_grad_norm_(parameters)
            self._scaler.step(optimizer)
            self._scaler.update()
        else:
            norm = None
        return norm

    def state_dict(self):
        return self._scaler.state_dict()

    def load_state_dict(self, state_dict):
        self._scaler.load_state_dict(state_dict)


def get_conv2d(in_channels, out_channels, kernel_size, stride, padding, dilation, groups, bias):
    if type(kernel_size) is int:
        use_large_impl = kernel_size > 5
    else:
        assert len(kernel_size) == 2 and kernel_size[0] == kernel_size[1]
        use_large_impl = kernel_size[0] > 5
    # has_large_impl = 'LARGE_KERNEL_CONV_IMPL' in os.environ
    try:
        from depthwise_conv2d_implicit_gemm import DepthWiseConv2dImplicitGEMM
        has_large_impl = True
    except:
        has_large_impl = False
    if has_large_impl and in_channels == out_channels and out_channels == groups and use_large_impl and stride == 1 and padding == kernel_size // 2 and dilation == 1:
        # if not os.environ['LARGE_KERNEL_CONV_IMPL'] in sys.path:
        #     sys.path.append(os.environ['LARGE_KERNEL_CONV_IMPL'])
        #   Please follow the instructions https://github.com/DingXiaoH/RepLKNet-pytorch/blob/main/README.md
        #   export LARGE_KERNEL_CONV_IMPL=absolute_path_to_where_you_cloned_the_example (i.e., depthwise_conv2d_implicit_gemm.py)
        # TODO more efficient PyTorch implementations of large-kernel convolutions. Pull requests are welcomed.
        # Or you may try MegEngine. We have integrated an efficient implementation into MegEngine and it will automatically use it.
        
        return DepthWiseConv2dImplicitGEMM(in_channels, kernel_size, bias=bias)
    else:
        return nn.Conv2d(in_channels=in_channels, out_channels=out_channels, kernel_size=kernel_size, stride=stride,
                         padding=padding, dilation=dilation, groups=groups, bias=bias)

def get_wandb_keys(filename):
    f = open(filename)
    keys = f.readline().strip()
    f.close()
    return keys

def GET_RANK():
    if dist.is_initialized():
        return dist.get_rank()
    else:
        return 0

def GET_WORLD_SIZE():
    if dist.is_initialized():
        return dist.get_world_size()
    else:
        return 1

def is_main_process():
    if not dist.is_initialized():
        return True
    if dist.is_initialized() and dist.get_rank() == 0:
        return True
    return False

def load_checkpoint(config, model, model_ema, optimizer, lr_scheduler, logger, loss_scaler=None):
    logger.info(f"==============> Resuming form {config.MODEL.RESUME}....................")
    if config.MODEL.RESUME.startswith('https'):
        checkpoint = torch.hub.load_state_dict_from_url(
            config.MODEL.RESUME, map_location='cpu', check_hash=True)
    else:
        checkpoint = torch.load(config.MODEL.RESUME, map_location='cpu')
    msg = model.load_state_dict(checkpoint['model'], strict=False)
    logger.info(msg)
    if model_ema is not None:
        if 'model_ema' in checkpoint.keys() and checkpoint['model_ema'] is not None:
            msg = model_ema.load_state_dict(checkpoint['model_ema'], strict=False)
        else:
            msg = model_ema.load_state_dict(checkpoint['model'], strict=False)
    logger.info(f'EMA: {msg}')
    max_accuracy = 0.0
    if not config.EVAL_MODE and 'optimizer' in checkpoint and 'lr_scheduler' in checkpoint and 'epoch' in checkpoint and config.RESUME_OPTIMIZER:
        if 'scaler' in checkpoint and loss_scaler is not None:
            loss_scaler.load_state_dict(checkpoint['scaler'])
        optimizer.load_state_dict(checkpoint['optimizer'])
        lr_scheduler.load_state_dict(checkpoint['lr_scheduler'])
        config.defrost()
        config.TRAIN.START_EPOCH = checkpoint['epoch'] + 1
        config.freeze()
        if 'amp' in checkpoint and config.AMP_OPT_LEVEL != "O0" and checkpoint['config'].AMP_OPT_LEVEL != "O0":
            amp.load_state_dict(checkpoint['amp'])
        logger.info(f"=> loaded successfully '{config.MODEL.RESUME}' (epoch {checkpoint['epoch']})")
        if 'max_accuracy' in checkpoint:
            max_accuracy = checkpoint['max_accuracy']

    del checkpoint
    torch.cuda.empty_cache()
    return max_accuracy


def save_checkpoint(config, epoch, model, model_ema, max_accuracy, optimizer, lr_scheduler, logger, loss_scaler=None):
    save_state = {'model': model.state_dict(),
                  'model_ema': model_ema.state_dict() if model_ema is not None else None,
                  'optimizer': optimizer.state_dict(),
                  'lr_scheduler': lr_scheduler.state_dict(),
                  'loss_scaler': loss_scaler.state_dict() if loss_scaler is not None else loss_scaler,
                  'max_accuracy': max_accuracy,
                  'epoch': epoch,
                  'config': config}
    if config.AMP_OPT_LEVEL != "O0" and loss_scaler is None:
        save_state['amp'] = amp.state_dict()

    save_path = os.path.join(config.OUTPUT, f'ckpt_epoch_{epoch}.pth')
    logger.info(f"{save_path} saving......")
    torch.save(save_state, save_path)
    logger.info(f"{save_path} saved !!!")


def get_grad_norm(parameters, norm_type=2):
    if isinstance(parameters, torch.Tensor):
        parameters = [parameters]
    parameters = list(filter(lambda p: p.grad is not None, parameters))
    norm_type = float(norm_type)
    total_norm = 0
    for p in parameters:
        param_norm = p.grad.data.norm(norm_type)
        total_norm += param_norm.item() ** norm_type
    total_norm = total_norm ** (1. / norm_type)
    return total_norm


def auto_resume_helper(output_dir):
    checkpoints = os.listdir(output_dir)
    checkpoints = [ckpt for ckpt in checkpoints if ckpt.endswith('pth')]
    print(f"All checkpoints founded in {output_dir}: {checkpoints}")
    if len(checkpoints) > 0:
        latest_checkpoint = max([os.path.join(output_dir, d) for d in checkpoints], key=os.path.getmtime)
        print(f"The latest checkpoint founded: {latest_checkpoint}")
        resume_file = latest_checkpoint
    else:
        resume_file = None
    return resume_file

def load_pretrained(config, model, logger):
    logger.info(f"==============> Loading weight {config.MODEL.PRETRAINED} for fine-tuning......")
    checkpoint = torch.load(config.MODEL.PRETRAINED, map_location='cpu')
    state_dict = checkpoint['model']

    # delete relative_position_index since we always re-init it
    relative_position_index_keys = [k for k in state_dict.keys() if "relative_position_index" in k]
    for k in relative_position_index_keys:
        del state_dict[k]

    # delete relative_coords_table since we always re-init it
    relative_position_index_keys = [k for k in state_dict.keys() if "relative_coords_table" in k]
    for k in relative_position_index_keys:
        del state_dict[k]

    # delete attn_mask since we always re-init it
    attn_mask_keys = [k for k in state_dict.keys() if "attn_mask" in k]
    for k in attn_mask_keys:
        del state_dict[k]

    # bicubic interpolate relative_position_bias_table if not match
    relative_position_bias_table_keys = [k for k in state_dict.keys() if "relative_position_bias_table" in k]
    for k in relative_position_bias_table_keys:
        relative_position_bias_table_pretrained = state_dict[k]
        relative_position_bias_table_current = model.state_dict()[k]
        L1, nH1 = relative_position_bias_table_pretrained.size()
        L2, nH2 = relative_position_bias_table_current.size()
        if nH1 != nH2:
            logger.warning(f"Error in loading {k}, passing......")
        else:
            if L1 != L2:
                # bicubic interpolate relative_position_bias_table if not match
                S1 = int(L1 ** 0.5)
                S2 = int(L2 ** 0.5)
                relative_position_bias_table_pretrained_resized = torch.nn.functional.interpolate(
                    relative_position_bias_table_pretrained.permute(1, 0).view(1, nH1, S1, S1), size=(S2, S2),
                    mode='bicubic')
                state_dict[k] = relative_position_bias_table_pretrained_resized.view(nH2, L2).permute(1, 0)

    # bicubic interpolate absolute_pos_embed if not match
    absolute_pos_embed_keys = [k for k in state_dict.keys() if "absolute_pos_embed" in k]
    for k in absolute_pos_embed_keys:
        # dpe
        absolute_pos_embed_pretrained = state_dict[k]
        absolute_pos_embed_current = model.state_dict()[k]
        _, L1, C1 = absolute_pos_embed_pretrained.size()
        _, L2, C2 = absolute_pos_embed_current.size()
        if C1 != C1:
            logger.warning(f"Error in loading {k}, passing......")
        else:
            if L1 != L2:
                S1 = int(L1 ** 0.5)
                S2 = int(L2 ** 0.5)
                absolute_pos_embed_pretrained = absolute_pos_embed_pretrained.reshape(-1, S1, S1, C1)
                absolute_pos_embed_pretrained = absolute_pos_embed_pretrained.permute(0, 3, 1, 2)
                absolute_pos_embed_pretrained_resized = torch.nn.functional.interpolate(
                    absolute_pos_embed_pretrained, size=(S2, S2), mode='bicubic')
                absolute_pos_embed_pretrained_resized = absolute_pos_embed_pretrained_resized.permute(0, 2, 3, 1)
                absolute_pos_embed_pretrained_resized = absolute_pos_embed_pretrained_resized.flatten(1, 2)
                state_dict[k] = absolute_pos_embed_pretrained_resized

    # check classifier, if not match, then re-init classifier to zero
    head_bias_pretrained = state_dict['head.bias']
    Nc1 = head_bias_pretrained.shape[0]
    Nc2 = model.head.bias.shape[0]
    if (Nc1 != Nc2):
        if Nc1 == 21841 and Nc2 == 1000:
            logger.info("loading ImageNet-22K weight to ImageNet-1K ......")
            map22kto1k_path = f'data/map22kto1k.txt'
            with open(map22kto1k_path) as f:
                map22kto1k = f.readlines()
            map22kto1k = [int(id22k.strip()) for id22k in map22kto1k]
            state_dict['head.weight'] = state_dict['head.weight'][map22kto1k, :]
            state_dict['head.bias'] = state_dict['head.bias'][map22kto1k]
        else:
            torch.nn.init.constant_(model.head.bias, 0.)
            torch.nn.init.constant_(model.head.weight, 0.)
            del state_dict['head.weight']
            del state_dict['head.bias']
            logger.warning(f"Error in loading classifier head, re-init classifier head to 0")

    msg = model.load_state_dict(state_dict, strict=False)
    logger.warning(msg)

    logger.info(f"=> loaded successfully '{config.MODEL.PRETRAINED}'")

    del checkpoint
    torch.cuda.empty_cache()


def reduce_tensor(tensor):
    rt = tensor.clone()
    dist.all_reduce(rt, op=dist.ReduceOp.SUM)
    rt /= dist.get_world_size()
    return rt