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# Copyright (c) ByteDance, Inc. and its 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.
import math
from pprint import pformat
def lr_wd_annealing(optimizer, peak_lr, wd, wd_end, cur_it, wp_it, max_it):
wp_it = round(wp_it)
if cur_it < wp_it:
cur_lr = 0.005 * peak_lr + 0.995 * peak_lr * cur_it / wp_it
else:
ratio = (cur_it - wp_it) / (max_it-1 - wp_it)
cur_lr = 0.001 * peak_lr + 0.999 * peak_lr * (0.5 + 0.5 * math.cos(math.pi * ratio))
ratio = cur_it / (max_it-1)
cur_wd = wd_end + (wd - wd_end) * (0.5 + 0.5 * math.cos(math.pi * ratio))
inf = 1e6
min_lr, max_lr = inf, -1
min_wd, max_wd = inf, -1
for param_group in optimizer.param_groups:
param_group['lr'] = cur_lr * param_group.get('lr_scale', 1) # 'lr_scale' could be assigned
max_lr = max(max_lr, param_group['lr'])
min_lr = min(min_lr, param_group['lr'])
param_group['weight_decay'] = cur_wd * param_group.get('weight_decay_scale', 1)
max_wd = max(max_wd, param_group['weight_decay'])
if param_group['weight_decay'] > 0:
min_wd = min(min_wd, param_group['weight_decay'])
if min_lr == inf: min_lr = -1
if min_wd == inf: min_wd = -1
return min_lr, max_lr, min_wd, max_wd
def get_param_groups(model, nowd_keys=(), lr_scale=0.0):
with_lr_scale = hasattr(model, 'get_layer_id_and_scale_exp') and 0 < lr_scale < 1
print(f'[get_ft_param_groups][lr decay] with_lr_scale={with_lr_scale}, ft_lr_scale={lr_scale}')
para_groups, para_groups_dbg = {}, {}
for name, para in model.named_parameters():
if not para.requires_grad:
continue # frozen weights
if len(para.shape) == 1 or name.endswith('.bias') or any(k in name for k in nowd_keys):
wd_scale, group_name = 0., 'no_decay'
else:
wd_scale, group_name = 1., 'decay'
if with_lr_scale:
layer_id, scale_exp = model.get_layer_id_and_scale_exp(name)
group_name = f'layer{layer_id}_' + group_name
cur_lr_scale = lr_scale ** scale_exp
dbg = f'[layer {layer_id}][sc = {lr_scale} ** {scale_exp}]'
else:
cur_lr_scale = 1
dbg = f'[no scale]'
if group_name not in para_groups:
para_groups[group_name] = {'params': [], 'weight_decay_scale': wd_scale, 'lr_scale': cur_lr_scale}
para_groups_dbg[group_name] = {'params': [], 'weight_decay_scale': wd_scale, 'lr_scale': dbg}
para_groups[group_name]['params'].append(para)
para_groups_dbg[group_name]['params'].append(name)
for g in para_groups_dbg.values():
g['params'] = pformat(', '.join(g['params']), width=200)
print(f'[get_ft_param_groups] param groups = \n{pformat(para_groups_dbg, indent=2, width=250)}\n')
return list(para_groups.values())