You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
pytorch-image-models/timm/models/_builder.py

410 lines
17 KiB

import dataclasses
import logging
import os
from copy import deepcopy
from typing import Optional, Dict, Callable, Any, Tuple
from torch import nn as nn
from torch.hub import load_state_dict_from_url
from timm.models._features import FeatureListNet, FeatureHookNet
from timm.models._features_fx import FeatureGraphNet
from timm.models._helpers import load_state_dict
from timm.models._hub import has_hf_hub, download_cached_file, check_cached_file, load_state_dict_from_hf
from timm.models._manipulate import adapt_input_conv
from timm.models._pretrained import PretrainedCfg
from timm.models._prune import adapt_model_from_file
from timm.models._registry import get_pretrained_cfg
_logger = logging.getLogger(__name__)
# Global variables for rarely used pretrained checkpoint download progress and hash check.
# Use set_pretrained_download_progress / set_pretrained_check_hash functions to toggle.
_DOWNLOAD_PROGRESS = False
_CHECK_HASH = False
__all__ = ['set_pretrained_download_progress', 'set_pretrained_check_hash', 'load_custom_pretrained', 'load_pretrained',
'pretrained_cfg_for_features', 'resolve_pretrained_cfg', 'build_model_with_cfg']
def _resolve_pretrained_source(pretrained_cfg):
cfg_source = pretrained_cfg.get('source', '')
pretrained_url = pretrained_cfg.get('url', None)
pretrained_file = pretrained_cfg.get('file', None)
hf_hub_id = pretrained_cfg.get('hf_hub_id', None)
# resolve where to load pretrained weights from
load_from = ''
pretrained_loc = ''
if cfg_source == 'hf-hub' and has_hf_hub(necessary=True):
# hf-hub specified as source via model identifier
load_from = 'hf-hub'
assert hf_hub_id
pretrained_loc = hf_hub_id
else:
# default source == timm or unspecified
if pretrained_file:
# file load override is the highest priority if set
load_from = 'file'
pretrained_loc = pretrained_file
else:
# next, HF hub is prioritized unless a valid cached version of weights exists already
cached_url_valid = check_cached_file(pretrained_url) if pretrained_url else False
if hf_hub_id and has_hf_hub(necessary=True) and not cached_url_valid:
# hf-hub available as alternate weight source in default_cfg
load_from = 'hf-hub'
pretrained_loc = hf_hub_id
elif pretrained_url:
load_from = 'url'
pretrained_loc = pretrained_url
if load_from == 'hf-hub' and pretrained_cfg.get('hf_hub_filename', None):
# if a filename override is set, return tuple for location w/ (hub_id, filename)
pretrained_loc = pretrained_loc, pretrained_cfg['hf_hub_filename']
return load_from, pretrained_loc
def set_pretrained_download_progress(enable=True):
""" Set download progress for pretrained weights on/off (globally). """
global _DOWNLOAD_PROGRESS
_DOWNLOAD_PROGRESS = enable
def set_pretrained_check_hash(enable=True):
""" Set hash checking for pretrained weights on/off (globally). """
global _CHECK_HASH
_CHECK_HASH = enable
def load_custom_pretrained(
model: nn.Module,
pretrained_cfg: Optional[Dict] = None,
load_fn: Optional[Callable] = None,
):
r"""Loads a custom (read non .pth) weight file
Downloads checkpoint file into cache-dir like torch.hub based loaders, but calls
a passed in custom load fun, or the `load_pretrained` model member fn.
If the object is already present in `model_dir`, it's deserialized and returned.
The default value of `model_dir` is ``<hub_dir>/checkpoints`` where
`hub_dir` is the directory returned by :func:`~torch.hub.get_dir`.
Args:
model: The instantiated model to load weights into
pretrained_cfg (dict): Default pretrained model cfg
load_fn: An external standalone fn that loads weights into provided model, otherwise a fn named
'laod_pretrained' on the model will be called if it exists
"""
pretrained_cfg = pretrained_cfg or getattr(model, 'pretrained_cfg', None)
if not pretrained_cfg:
_logger.warning("Invalid pretrained config, cannot load weights.")
return
load_from, pretrained_loc = _resolve_pretrained_source(pretrained_cfg)
if not load_from:
_logger.warning("No pretrained weights exist for this model. Using random initialization.")
return
if load_from == 'hf-hub': # FIXME
_logger.warning("Hugging Face hub not currently supported for custom load pretrained models.")
elif load_from == 'url':
pretrained_loc = download_cached_file(
pretrained_loc,
check_hash=_CHECK_HASH,
progress=_DOWNLOAD_PROGRESS,
)
if load_fn is not None:
load_fn(model, pretrained_loc)
elif hasattr(model, 'load_pretrained'):
model.load_pretrained(pretrained_loc)
else:
_logger.warning("Valid function to load pretrained weights is not available, using random initialization.")
def load_pretrained(
model: nn.Module,
pretrained_cfg: Optional[Dict] = None,
num_classes: int = 1000,
in_chans: int = 3,
filter_fn: Optional[Callable] = None,
strict: bool = True,
):
""" Load pretrained checkpoint
Args:
model (nn.Module) : PyTorch model module
pretrained_cfg (Optional[Dict]): configuration for pretrained weights / target dataset
num_classes (int): num_classes for target model
in_chans (int): in_chans for target model
filter_fn (Optional[Callable]): state_dict filter fn for load (takes state_dict, model as args)
strict (bool): strict load of checkpoint
"""
pretrained_cfg = pretrained_cfg or getattr(model, 'pretrained_cfg', None)
if not pretrained_cfg:
_logger.warning("Invalid pretrained config, cannot load weights.")
return
load_from, pretrained_loc = _resolve_pretrained_source(pretrained_cfg)
if load_from == 'file':
_logger.info(f'Loading pretrained weights from file ({pretrained_loc})')
state_dict = load_state_dict(pretrained_loc)
elif load_from == 'url':
_logger.info(f'Loading pretrained weights from url ({pretrained_loc})')
if pretrained_cfg.get('custom_load', False):
pretrained_loc = download_cached_file(
pretrained_loc,
progress=_DOWNLOAD_PROGRESS,
check_hash=_CHECK_HASH,
)
model.load_pretrained(pretrained_loc)
return
else:
state_dict = load_state_dict_from_url(
pretrained_loc,
map_location='cpu',
progress=_DOWNLOAD_PROGRESS,
check_hash=_CHECK_HASH,
)
elif load_from == 'hf-hub':
_logger.info(f'Loading pretrained weights from Hugging Face hub ({pretrained_loc})')
if isinstance(pretrained_loc, (list, tuple)):
state_dict = load_state_dict_from_hf(*pretrained_loc)
else:
state_dict = load_state_dict_from_hf(pretrained_loc)
else:
_logger.warning("No pretrained weights exist or were found for this model. Using random initialization.")
return
if filter_fn is not None:
# for backwards compat with filter fn that take one arg, try one first, the two
try:
state_dict = filter_fn(state_dict)
except TypeError:
state_dict = filter_fn(state_dict, model)
input_convs = pretrained_cfg.get('first_conv', None)
if input_convs is not None and in_chans != 3:
if isinstance(input_convs, str):
input_convs = (input_convs,)
for input_conv_name in input_convs:
weight_name = input_conv_name + '.weight'
try:
state_dict[weight_name] = adapt_input_conv(in_chans, state_dict[weight_name])
_logger.info(
f'Converted input conv {input_conv_name} pretrained weights from 3 to {in_chans} channel(s)')
except NotImplementedError as e:
del state_dict[weight_name]
strict = False
_logger.warning(
f'Unable to convert pretrained {input_conv_name} weights, using random init for this layer.')
classifiers = pretrained_cfg.get('classifier', None)
label_offset = pretrained_cfg.get('label_offset', 0)
if classifiers is not None:
if isinstance(classifiers, str):
classifiers = (classifiers,)
if num_classes != pretrained_cfg['num_classes']:
for classifier_name in classifiers:
# completely discard fully connected if model num_classes doesn't match pretrained weights
state_dict.pop(classifier_name + '.weight', None)
state_dict.pop(classifier_name + '.bias', None)
strict = False
elif label_offset > 0:
for classifier_name in classifiers:
# special case for pretrained weights with an extra background class in pretrained weights
classifier_weight = state_dict[classifier_name + '.weight']
state_dict[classifier_name + '.weight'] = classifier_weight[label_offset:]
classifier_bias = state_dict[classifier_name + '.bias']
state_dict[classifier_name + '.bias'] = classifier_bias[label_offset:]
model.load_state_dict(state_dict, strict=strict)
def pretrained_cfg_for_features(pretrained_cfg):
pretrained_cfg = deepcopy(pretrained_cfg)
# remove default pretrained cfg fields that don't have much relevance for feature backbone
to_remove = ('num_classes', 'classifier', 'global_pool') # add default final pool size?
for tr in to_remove:
pretrained_cfg.pop(tr, None)
return pretrained_cfg
def _filter_kwargs(kwargs, names):
if not kwargs or not names:
return
for n in names:
kwargs.pop(n, None)
def _update_default_kwargs(pretrained_cfg, kwargs, kwargs_filter):
""" Update the default_cfg and kwargs before passing to model
Args:
pretrained_cfg: input pretrained cfg (updated in-place)
kwargs: keyword args passed to model build fn (updated in-place)
kwargs_filter: keyword arg keys that must be removed before model __init__
"""
# Set model __init__ args that can be determined by default_cfg (if not already passed as kwargs)
default_kwarg_names = ('num_classes', 'global_pool', 'in_chans')
if pretrained_cfg.get('fixed_input_size', False):
# if fixed_input_size exists and is True, model takes an img_size arg that fixes its input size
default_kwarg_names += ('img_size',)
for n in default_kwarg_names:
# for legacy reasons, model __init__args uses img_size + in_chans as separate args while
# pretrained_cfg has one input_size=(C, H ,W) entry
if n == 'img_size':
input_size = pretrained_cfg.get('input_size', None)
if input_size is not None:
assert len(input_size) == 3
kwargs.setdefault(n, input_size[-2:])
elif n == 'in_chans':
input_size = pretrained_cfg.get('input_size', None)
if input_size is not None:
assert len(input_size) == 3
kwargs.setdefault(n, input_size[0])
else:
default_val = pretrained_cfg.get(n, None)
if default_val is not None:
kwargs.setdefault(n, pretrained_cfg[n])
# Filter keyword args for task specific model variants (some 'features only' models, etc.)
_filter_kwargs(kwargs, names=kwargs_filter)
def resolve_pretrained_cfg(
variant: str,
pretrained_cfg=None,
pretrained_cfg_overlay=None,
) -> PretrainedCfg:
model_with_tag = variant
pretrained_tag = None
if pretrained_cfg:
if isinstance(pretrained_cfg, dict):
# pretrained_cfg dict passed as arg, validate by converting to PretrainedCfg
pretrained_cfg = PretrainedCfg(**pretrained_cfg)
elif isinstance(pretrained_cfg, str):
pretrained_tag = pretrained_cfg
pretrained_cfg = None
# fallback to looking up pretrained cfg in model registry by variant identifier
if not pretrained_cfg:
if pretrained_tag:
model_with_tag = '.'.join([variant, pretrained_tag])
pretrained_cfg = get_pretrained_cfg(model_with_tag)
if not pretrained_cfg:
_logger.warning(
f"No pretrained configuration specified for {model_with_tag} model. Using a default."
f" Please add a config to the model pretrained_cfg registry or pass explicitly.")
pretrained_cfg = PretrainedCfg() # instance with defaults
pretrained_cfg_overlay = pretrained_cfg_overlay or {}
if not pretrained_cfg.architecture:
pretrained_cfg_overlay.setdefault('architecture', variant)
pretrained_cfg = dataclasses.replace(pretrained_cfg, **pretrained_cfg_overlay)
return pretrained_cfg
def build_model_with_cfg(
model_cls: Callable,
variant: str,
pretrained: bool,
pretrained_cfg: Optional[Dict] = None,
pretrained_cfg_overlay: Optional[Dict] = None,
model_cfg: Optional[Any] = None,
feature_cfg: Optional[Dict] = None,
pretrained_strict: bool = True,
pretrained_filter_fn: Optional[Callable] = None,
kwargs_filter: Optional[Tuple[str]] = None,
**kwargs,
):
""" Build model with specified default_cfg and optional model_cfg
This helper fn aids in the construction of a model including:
* handling default_cfg and associated pretrained weight loading
* passing through optional model_cfg for models with config based arch spec
* features_only model adaptation
* pruning config / model adaptation
Args:
model_cls (nn.Module): model class
variant (str): model variant name
pretrained (bool): load pretrained weights
pretrained_cfg (dict): model's pretrained weight/task config
model_cfg (Optional[Dict]): model's architecture config
feature_cfg (Optional[Dict]: feature extraction adapter config
pretrained_strict (bool): load pretrained weights strictly
pretrained_filter_fn (Optional[Callable]): filter callable for pretrained weights
kwargs_filter (Optional[Tuple]): kwargs to filter before passing to model
**kwargs: model args passed through to model __init__
"""
pruned = kwargs.pop('pruned', False)
features = False
feature_cfg = feature_cfg or {}
# resolve and update model pretrained config and model kwargs
pretrained_cfg = resolve_pretrained_cfg(
variant,
pretrained_cfg=pretrained_cfg,
pretrained_cfg_overlay=pretrained_cfg_overlay
)
# FIXME converting back to dict, PretrainedCfg use should be propagated further, but not into model
pretrained_cfg = pretrained_cfg.to_dict()
_update_default_kwargs(pretrained_cfg, kwargs, kwargs_filter)
# Setup for feature extraction wrapper done at end of this fn
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')
# Instantiate the model
if model_cfg is None:
model = model_cls(**kwargs)
else:
model = model_cls(cfg=model_cfg, **kwargs)
model.pretrained_cfg = pretrained_cfg
model.default_cfg = model.pretrained_cfg # alias for backwards compat
if pruned:
model = adapt_model_from_file(model, variant)
# For classification models, check class attr, then kwargs, then default to 1k, otherwise 0 for feats
num_classes_pretrained = 0 if features else getattr(model, 'num_classes', kwargs.get('num_classes', 1000))
if pretrained:
load_pretrained(
model,
pretrained_cfg=pretrained_cfg,
num_classes=num_classes_pretrained,
in_chans=kwargs.get('in_chans', 3),
filter_fn=pretrained_filter_fn,
strict=pretrained_strict,
)
# Wrap the model in a feature extraction module if enabled
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
elif feature_cls == 'fx':
feature_cls = FeatureGraphNet
else:
assert False, f'Unknown feature class {feature_cls}'
model = feature_cls(model, **feature_cfg)
model.pretrained_cfg = pretrained_cfg_for_features(pretrained_cfg) # add back default_cfg
model.default_cfg = model.pretrained_cfg # alias for backwards compat
return model