import logging
import os
from collections import OrderedDict
from copy import deepcopy
from typing import Callable
import torch
import torch.nn as nn
import torch.utils.model_zoo as model_zoo
from .features import FeatureListNet, FeatureDictNet, FeatureHookNet
from .layers import Conv2dSame
def load_state_dict(checkpoint_path, use_ema=False):
if checkpoint_path and os.path.isfile(checkpoint_path):
checkpoint = torch.load(checkpoint_path, map_location='cpu')
state_dict_key = 'state_dict'
if isinstance(checkpoint, dict):
if use_ema and 'state_dict_ema' in checkpoint:
state_dict_key = 'state_dict_ema'
if state_dict_key and state_dict_key in checkpoint:
new_state_dict = OrderedDict()
for k, v in checkpoint[state_dict_key].items():
# strip `module.` prefix
name = k[7:] if k.startswith('module') else k
new_state_dict[name] = v
state_dict = new_state_dict
else:
state_dict = checkpoint
logging.info("Loaded {} from checkpoint '{}'".format(state_dict_key, checkpoint_path))
return state_dict
else:
logging.error("No checkpoint found at '{}'".format(checkpoint_path))
raise FileNotFoundError()
def load_checkpoint(model, checkpoint_path, use_ema=False, strict=True):
state_dict = load_state_dict(checkpoint_path, use_ema)
model.load_state_dict(state_dict, strict=strict)
def resume_checkpoint(model, checkpoint_path):
other_state = {}
resume_epoch = None
if os.path.isfile(checkpoint_path):
checkpoint = torch.load(checkpoint_path, map_location='cpu')
if isinstance(checkpoint, dict) and 'state_dict' in checkpoint:
new_state_dict = OrderedDict()
for k, v in checkpoint['state_dict'].items():
name = k[7:] if k.startswith('module') else k
new_state_dict[name] = v
model.load_state_dict(new_state_dict)
if 'optimizer' in checkpoint:
other_state['optimizer'] = checkpoint['optimizer']
if 'amp' in checkpoint:
other_state['amp'] = checkpoint['amp']
if 'epoch' in checkpoint:
resume_epoch = checkpoint['epoch']
if 'version' in checkpoint and checkpoint['version'] > 1:
resume_epoch += 1 # start at the next epoch, old checkpoints incremented before save
logging.info("Loaded checkpoint '{}' (epoch {})".format(checkpoint_path, checkpoint['epoch']))
else:
model.load_state_dict(checkpoint)
logging.info("Loaded checkpoint '{}'".format(checkpoint_path))
return other_state, resume_epoch
else:
logging.error("No checkpoint found at '{}'".format(checkpoint_path))
raise FileNotFoundError()
def load_pretrained(model, cfg=None, num_classes=1000, in_chans=3, filter_fn=None, strict=True):
if cfg is None:
cfg = getattr(model, 'default_cfg')
if cfg is None or 'url' not in cfg or not cfg['url']:
logging.warning("Pretrained model URL is invalid, using random initialization.")
return
state_dict = model_zoo.load_url(cfg['url'], progress=False, map_location='cpu')
if filter_fn is not None:
state_dict = filter_fn(state_dict)
if in_chans == 1:
conv1_name = cfg['first_conv']
logging.info('Converting first conv (%s) from 3 to 1 channel' % conv1_name)
conv1_weight = state_dict[conv1_name + '.weight']
state_dict[conv1_name + '.weight'] = conv1_weight.sum(dim=1, keepdim=True)
elif in_chans != 3:
assert False, "Invalid in_chans for pretrained weights"
classifier_name = cfg['classifier']
if num_classes == 1000 and cfg['num_classes'] == 1001:
# special case for imagenet trained models with extra background class in pretrained weights
classifier_weight = state_dict[classifier_name + '.weight']
state_dict[classifier_name + '.weight'] = classifier_weight[1:]
classifier_bias = state_dict[classifier_name + '.bias']
state_dict[classifier_name + '.bias'] = classifier_bias[1:]
elif num_classes != cfg['num_classes']:
# completely discard fully connected for all other differences between pretrained and created model
del state_dict[classifier_name + '.weight']
del state_dict[classifier_name + '.bias']
strict = False
model.load_state_dict(state_dict, strict=strict)
def extract_layer(model, layer):
layer = layer.split('.')
module = model
if hasattr(model, 'module') and layer[0] != 'module':
module = model.module
if not hasattr(model, 'module') and layer[0] == 'module':
layer = layer[1:]
for l in layer:
if hasattr(module, l):
if not l.isdigit():
module = getattr(module, l)
else:
module = module[int(l)]
else:
return module
return module
def set_layer(model, layer, val):
layer = layer.split('.')
module = model
if hasattr(model, 'module') and layer[0] != 'module':
module = model.module
lst_index = 0
module2 = module
for l in layer:
if hasattr(module2, l):
if not l.isdigit():
module2 = getattr(module2, l)
else:
module2 = module2[int(l)]
lst_index += 1
lst_index -= 1
for l in layer[:lst_index]:
if not l.isdigit():
module = getattr(module, l)
else:
module = module[int(l)]
l = layer[lst_index]
setattr(module, l, val)
def adapt_model_from_string(parent_module, model_string):
separator = '***'
state_dict = {}
lst_shape = model_string.split(separator)
for k in lst_shape:
k = k.split(':')
key = k[0]
shape = k[1][1:-1].split(',')
if shape[0] != '':
state_dict[key] = [int(i) for i in shape]
new_module = deepcopy(parent_module)
for n, m in parent_module.named_modules():
old_module = extract_layer(parent_module, n)
if isinstance(old_module, nn.Conv2d) or isinstance(old_module, Conv2dSame):
if isinstance(old_module, Conv2dSame):
conv = Conv2dSame
else:
conv = nn.Conv2d
s = state_dict[n + '.weight']
in_channels = s[1]
out_channels = s[0]
g = 1
if old_module.groups > 1:
in_channels = out_channels
g = in_channels
new_conv = conv(
in_channels=in_channels, out_channels=out_channels, kernel_size=old_module.kernel_size,
bias=old_module.bias is not None, padding=old_module.padding, dilation=old_module.dilation,
groups=g, stride=old_module.stride)
set_layer(new_module, n, new_conv)
if isinstance(old_module, nn.BatchNorm2d):
new_bn = nn.BatchNorm2d(
num_features=state_dict[n + '.weight'][0], eps=old_module.eps, momentum=old_module.momentum,
affine=old_module.affine, track_running_stats=True)
set_layer(new_module, n, new_bn)
if isinstance(old_module, nn.Linear):
new_fc = nn.Linear(
in_features=state_dict[n + '.weight'][1], out_features=old_module.out_features,
bias=old_module.bias is not None)
set_layer(new_module, n, new_fc)
new_module.eval()
parent_module.eval()
return new_module
def adapt_model_from_file(parent_module, model_variant):
adapt_file = os.path.join(os.path.dirname(__file__), 'pruned', model_variant + '.txt')
with open(adapt_file, 'r') as f:
return adapt_model_from_string(parent_module, f.read().strip())
def build_model_with_cfg(
model_cls: Callable,
variant: str,
pretrained: bool,
default_cfg: dict,
model_cfg: dict = None,
feature_cfg: dict = None,
pretrained_strict: bool = True,
pretrained_filter_fn: Callable = None,
**kwargs):
pruned = kwargs.pop('pruned', False)
features = False
feature_cfg = feature_cfg or {}
if kwargs.pop('features_only', False):
features = True
feature_cfg.setdefault('out_indices', (0, 1, 2, 3, 4))
if 'out_indices' in kwargs:
feature_cfg['out_indices'] = kwargs.pop('out_indices')
model = model_cls(**kwargs) if model_cfg is None else model_cls(cfg=model_cfg, **kwargs)
model.default_cfg = deepcopy(default_cfg)
if pruned:
model = adapt_model_from_file(model, variant)
if pretrained:
load_pretrained(
model,
num_classes=kwargs.get('num_classes', 0),
in_chans=kwargs.get('in_chans', 3),
filter_fn=pretrained_filter_fn, strict=pretrained_strict)
if features:
feature_cls = FeatureListNet
if 'feature_cls' in feature_cfg:
feature_cls = feature_cfg.pop('feature_cls')
if isinstance(feature_cls, str):
feature_cls = feature_cls.lower()
if 'hook' in feature_cls:
feature_cls = FeatureHookNet
else:
assert False, f'Unknown feature class {feature_cls}'
model = feature_cls(model, **feature_cfg)
return model