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# Copyright (c) Meta Platforms, Inc. and affiliates. | |
# All rights reserved. | |
# | |
# This source code is licensed under the license found in the | |
# LICENSE file in the root directory of this source tree. | |
from collections import defaultdict | |
import logging | |
logger = logging.getLogger("dinov2") | |
def get_vit_lr_decay_rate(name, lr_decay_rate=1.0, num_layers=12, force_is_backbone=False, chunked_blocks=False): | |
""" | |
Calculate lr decay rate for different ViT blocks. | |
Args: | |
name (string): parameter name. | |
lr_decay_rate (float): base lr decay rate. | |
num_layers (int): number of ViT blocks. | |
Returns: | |
lr decay rate for the given parameter. | |
""" | |
layer_id = num_layers + 1 | |
if name.startswith("backbone") or force_is_backbone: | |
if ".pos_embed" in name or ".patch_embed" in name or ".mask_token" in name or ".cls_token" in name: | |
layer_id = 0 | |
elif force_is_backbone and ( | |
"pos_embed" in name or "patch_embed" in name or "mask_token" in name or "cls_token" in name | |
): | |
layer_id = 0 | |
elif ".blocks." in name and ".residual." not in name: | |
layer_id = int(name[name.find(".blocks.") :].split(".")[2]) + 1 | |
elif chunked_blocks and "blocks." in name and "residual." not in name: | |
layer_id = int(name[name.find("blocks.") :].split(".")[2]) + 1 | |
elif "blocks." in name and "residual." not in name: | |
layer_id = int(name[name.find("blocks.") :].split(".")[1]) + 1 | |
return lr_decay_rate ** (num_layers + 1 - layer_id) | |
def get_params_groups_with_decay(model, lr_decay_rate=1.0, patch_embed_lr_mult=1.0): | |
chunked_blocks = False | |
if hasattr(model, "n_blocks"): | |
logger.info("chunked fsdp") | |
n_blocks = model.n_blocks | |
chunked_blocks = model.chunked_blocks | |
elif hasattr(model, "blocks"): | |
logger.info("first code branch") | |
n_blocks = len(model.blocks) | |
elif hasattr(model, "backbone"): | |
logger.info("second code branch") | |
n_blocks = len(model.backbone.blocks) | |
else: | |
logger.info("else code branch") | |
n_blocks = 0 | |
all_param_groups = [] | |
for name, param in model.named_parameters(): | |
name = name.replace("_fsdp_wrapped_module.", "") | |
if not param.requires_grad: | |
continue | |
decay_rate = get_vit_lr_decay_rate( | |
name, lr_decay_rate, num_layers=n_blocks, force_is_backbone=n_blocks > 0, chunked_blocks=chunked_blocks | |
) | |
d = {"params": param, "is_last_layer": False, "lr_multiplier": decay_rate, "wd_multiplier": 1.0, "name": name} | |
if "last_layer" in name: | |
d.update({"is_last_layer": True}) | |
if name.endswith(".bias") or "norm" in name or "gamma" in name: | |
d.update({"wd_multiplier": 0.0}) | |
if "patch_embed" in name: | |
d.update({"lr_multiplier": d["lr_multiplier"] * patch_embed_lr_mult}) | |
all_param_groups.append(d) | |
logger.info(f"""{name}: lr_multiplier: {d["lr_multiplier"]}, wd_multiplier: {d["wd_multiplier"]}""") | |
return all_param_groups | |
def fuse_params_groups(all_params_groups, keys=("lr_multiplier", "wd_multiplier", "is_last_layer")): | |
fused_params_groups = defaultdict(lambda: {"params": []}) | |
for d in all_params_groups: | |
identifier = "" | |
for k in keys: | |
identifier += k + str(d[k]) + "_" | |
for k in keys: | |
fused_params_groups[identifier][k] = d[k] | |
fused_params_groups[identifier]["params"].append(d["params"]) | |
return fused_params_groups.values() | |