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| # Copyright (c) OpenMMLab. All rights reserved. | |
| import warnings | |
| import torch | |
| from torch.nn import GroupNorm, LayerNorm | |
| from custom_mmpkg.custom_mmcv.utils import _BatchNorm, _InstanceNorm, build_from_cfg, is_list_of | |
| from custom_mmpkg.custom_mmcv.utils.ext_loader import check_ops_exist | |
| from .builder import OPTIMIZER_BUILDERS, OPTIMIZERS | |
| class DefaultOptimizerConstructor: | |
| """Default constructor for optimizers. | |
| By default each parameter share the same optimizer settings, and we | |
| provide an argument ``paramwise_cfg`` to specify parameter-wise settings. | |
| It is a dict and may contain the following fields: | |
| - ``custom_keys`` (dict): Specified parameters-wise settings by keys. If | |
| one of the keys in ``custom_keys`` is a substring of the name of one | |
| parameter, then the setting of the parameter will be specified by | |
| ``custom_keys[key]`` and other setting like ``bias_lr_mult`` etc. will | |
| be ignored. It should be noted that the aforementioned ``key`` is the | |
| longest key that is a substring of the name of the parameter. If there | |
| are multiple matched keys with the same length, then the key with lower | |
| alphabet order will be chosen. | |
| ``custom_keys[key]`` should be a dict and may contain fields ``lr_mult`` | |
| and ``decay_mult``. See Example 2 below. | |
| - ``bias_lr_mult`` (float): It will be multiplied to the learning | |
| rate for all bias parameters (except for those in normalization | |
| layers and offset layers of DCN). | |
| - ``bias_decay_mult`` (float): It will be multiplied to the weight | |
| decay for all bias parameters (except for those in | |
| normalization layers, depthwise conv layers, offset layers of DCN). | |
| - ``norm_decay_mult`` (float): It will be multiplied to the weight | |
| decay for all weight and bias parameters of normalization | |
| layers. | |
| - ``dwconv_decay_mult`` (float): It will be multiplied to the weight | |
| decay for all weight and bias parameters of depthwise conv | |
| layers. | |
| - ``dcn_offset_lr_mult`` (float): It will be multiplied to the learning | |
| rate for parameters of offset layer in the deformable convs | |
| of a model. | |
| - ``bypass_duplicate`` (bool): If true, the duplicate parameters | |
| would not be added into optimizer. Default: False. | |
| Note: | |
| 1. If the option ``dcn_offset_lr_mult`` is used, the constructor will | |
| override the effect of ``bias_lr_mult`` in the bias of offset | |
| layer. So be careful when using both ``bias_lr_mult`` and | |
| ``dcn_offset_lr_mult``. If you wish to apply both of them to the | |
| offset layer in deformable convs, set ``dcn_offset_lr_mult`` | |
| to the original ``dcn_offset_lr_mult`` * ``bias_lr_mult``. | |
| 2. If the option ``dcn_offset_lr_mult`` is used, the constructor will | |
| apply it to all the DCN layers in the model. So be careful when | |
| the model contains multiple DCN layers in places other than | |
| backbone. | |
| Args: | |
| model (:obj:`nn.Module`): The model with parameters to be optimized. | |
| optimizer_cfg (dict): The config dict of the optimizer. | |
| Positional fields are | |
| - `type`: class name of the optimizer. | |
| Optional fields are | |
| - any arguments of the corresponding optimizer type, e.g., | |
| lr, weight_decay, momentum, etc. | |
| paramwise_cfg (dict, optional): Parameter-wise options. | |
| Example 1: | |
| >>> model = torch.nn.modules.Conv1d(1, 1, 1) | |
| >>> optimizer_cfg = dict(type='SGD', lr=0.01, momentum=0.9, | |
| >>> weight_decay=0.0001) | |
| >>> paramwise_cfg = dict(norm_decay_mult=0.) | |
| >>> optim_builder = DefaultOptimizerConstructor( | |
| >>> optimizer_cfg, paramwise_cfg) | |
| >>> optimizer = optim_builder(model) | |
| Example 2: | |
| >>> # assume model have attribute model.backbone and model.cls_head | |
| >>> optimizer_cfg = dict(type='SGD', lr=0.01, weight_decay=0.95) | |
| >>> paramwise_cfg = dict(custom_keys={ | |
| '.backbone': dict(lr_mult=0.1, decay_mult=0.9)}) | |
| >>> optim_builder = DefaultOptimizerConstructor( | |
| >>> optimizer_cfg, paramwise_cfg) | |
| >>> optimizer = optim_builder(model) | |
| >>> # Then the `lr` and `weight_decay` for model.backbone is | |
| >>> # (0.01 * 0.1, 0.95 * 0.9). `lr` and `weight_decay` for | |
| >>> # model.cls_head is (0.01, 0.95). | |
| """ | |
| def __init__(self, optimizer_cfg, paramwise_cfg=None): | |
| if not isinstance(optimizer_cfg, dict): | |
| raise TypeError('optimizer_cfg should be a dict', | |
| f'but got {type(optimizer_cfg)}') | |
| self.optimizer_cfg = optimizer_cfg | |
| self.paramwise_cfg = {} if paramwise_cfg is None else paramwise_cfg | |
| self.base_lr = optimizer_cfg.get('lr', None) | |
| self.base_wd = optimizer_cfg.get('weight_decay', None) | |
| self._validate_cfg() | |
| def _validate_cfg(self): | |
| if not isinstance(self.paramwise_cfg, dict): | |
| raise TypeError('paramwise_cfg should be None or a dict, ' | |
| f'but got {type(self.paramwise_cfg)}') | |
| if 'custom_keys' in self.paramwise_cfg: | |
| if not isinstance(self.paramwise_cfg['custom_keys'], dict): | |
| raise TypeError( | |
| 'If specified, custom_keys must be a dict, ' | |
| f'but got {type(self.paramwise_cfg["custom_keys"])}') | |
| if self.base_wd is None: | |
| for key in self.paramwise_cfg['custom_keys']: | |
| if 'decay_mult' in self.paramwise_cfg['custom_keys'][key]: | |
| raise ValueError('base_wd should not be None') | |
| # get base lr and weight decay | |
| # weight_decay must be explicitly specified if mult is specified | |
| if ('bias_decay_mult' in self.paramwise_cfg | |
| or 'norm_decay_mult' in self.paramwise_cfg | |
| or 'dwconv_decay_mult' in self.paramwise_cfg): | |
| if self.base_wd is None: | |
| raise ValueError('base_wd should not be None') | |
| def _is_in(self, param_group, param_group_list): | |
| assert is_list_of(param_group_list, dict) | |
| param = set(param_group['params']) | |
| param_set = set() | |
| for group in param_group_list: | |
| param_set.update(set(group['params'])) | |
| return not param.isdisjoint(param_set) | |
| def add_params(self, params, module, prefix='', is_dcn_module=None): | |
| """Add all parameters of module to the params list. | |
| The parameters of the given module will be added to the list of param | |
| groups, with specific rules defined by paramwise_cfg. | |
| Args: | |
| params (list[dict]): A list of param groups, it will be modified | |
| in place. | |
| module (nn.Module): The module to be added. | |
| prefix (str): The prefix of the module | |
| is_dcn_module (int|float|None): If the current module is a | |
| submodule of DCN, `is_dcn_module` will be passed to | |
| control conv_offset layer's learning rate. Defaults to None. | |
| """ | |
| # get param-wise options | |
| custom_keys = self.paramwise_cfg.get('custom_keys', {}) | |
| # first sort with alphabet order and then sort with reversed len of str | |
| sorted_keys = sorted(sorted(custom_keys.keys()), key=len, reverse=True) | |
| bias_lr_mult = self.paramwise_cfg.get('bias_lr_mult', 1.) | |
| bias_decay_mult = self.paramwise_cfg.get('bias_decay_mult', 1.) | |
| norm_decay_mult = self.paramwise_cfg.get('norm_decay_mult', 1.) | |
| dwconv_decay_mult = self.paramwise_cfg.get('dwconv_decay_mult', 1.) | |
| bypass_duplicate = self.paramwise_cfg.get('bypass_duplicate', False) | |
| dcn_offset_lr_mult = self.paramwise_cfg.get('dcn_offset_lr_mult', 1.) | |
| # special rules for norm layers and depth-wise conv layers | |
| is_norm = isinstance(module, | |
| (_BatchNorm, _InstanceNorm, GroupNorm, LayerNorm)) | |
| is_dwconv = ( | |
| isinstance(module, torch.nn.Conv2d) | |
| and module.in_channels == module.groups) | |
| for name, param in module.named_parameters(recurse=False): | |
| param_group = {'params': [param]} | |
| if not param.requires_grad: | |
| params.append(param_group) | |
| continue | |
| if bypass_duplicate and self._is_in(param_group, params): | |
| warnings.warn(f'{prefix} is duplicate. It is skipped since ' | |
| f'bypass_duplicate={bypass_duplicate}') | |
| continue | |
| # if the parameter match one of the custom keys, ignore other rules | |
| is_custom = False | |
| for key in sorted_keys: | |
| if key in f'{prefix}.{name}': | |
| is_custom = True | |
| lr_mult = custom_keys[key].get('lr_mult', 1.) | |
| param_group['lr'] = self.base_lr * lr_mult | |
| if self.base_wd is not None: | |
| decay_mult = custom_keys[key].get('decay_mult', 1.) | |
| param_group['weight_decay'] = self.base_wd * decay_mult | |
| break | |
| if not is_custom: | |
| # bias_lr_mult affects all bias parameters | |
| # except for norm.bias dcn.conv_offset.bias | |
| if name == 'bias' and not (is_norm or is_dcn_module): | |
| param_group['lr'] = self.base_lr * bias_lr_mult | |
| if (prefix.find('conv_offset') != -1 and is_dcn_module | |
| and isinstance(module, torch.nn.Conv2d)): | |
| # deal with both dcn_offset's bias & weight | |
| param_group['lr'] = self.base_lr * dcn_offset_lr_mult | |
| # apply weight decay policies | |
| if self.base_wd is not None: | |
| # norm decay | |
| if is_norm: | |
| param_group[ | |
| 'weight_decay'] = self.base_wd * norm_decay_mult | |
| # depth-wise conv | |
| elif is_dwconv: | |
| param_group[ | |
| 'weight_decay'] = self.base_wd * dwconv_decay_mult | |
| # bias lr and decay | |
| elif name == 'bias' and not is_dcn_module: | |
| # TODO: current bias_decay_mult will have affect on DCN | |
| param_group[ | |
| 'weight_decay'] = self.base_wd * bias_decay_mult | |
| params.append(param_group) | |
| if check_ops_exist(): | |
| from custom_mmpkg.custom_mmcv.ops import DeformConv2d, ModulatedDeformConv2d | |
| is_dcn_module = isinstance(module, | |
| (DeformConv2d, ModulatedDeformConv2d)) | |
| else: | |
| is_dcn_module = False | |
| for child_name, child_mod in module.named_children(): | |
| child_prefix = f'{prefix}.{child_name}' if prefix else child_name | |
| self.add_params( | |
| params, | |
| child_mod, | |
| prefix=child_prefix, | |
| is_dcn_module=is_dcn_module) | |
| def __call__(self, model): | |
| if hasattr(model, 'module'): | |
| model = model.module | |
| optimizer_cfg = self.optimizer_cfg.copy() | |
| # if no paramwise option is specified, just use the global setting | |
| if not self.paramwise_cfg: | |
| optimizer_cfg['params'] = model.parameters() | |
| return build_from_cfg(optimizer_cfg, OPTIMIZERS) | |
| # set param-wise lr and weight decay recursively | |
| params = [] | |
| self.add_params(params, model) | |
| optimizer_cfg['params'] = params | |
| return build_from_cfg(optimizer_cfg, OPTIMIZERS) | |