def build_optimizer(self, trn, epochs, adam_epsilon, weight_decay,
warmup_steps, lr, encoder_lr, **kwargs):
model = self.model_
encoder = model.encoder
num_training_steps = len(trn) * epochs // self.config.get(
'gradient_accumulation', 1)
encoder_parameters = list(encoder.parameters())
parameter_groups: List[Dict[str, Any]] = []
decoders = model.decoders
decoder_optimizers = dict()
for k, task in self.tasks.items():
decoder: torch.nn.Module = decoders[k]
decoder_parameters = list(decoder.parameters())
if task.separate_optimizer:
decoder_optimizers[k] = task.build_optimizer(decoder=decoder,
**kwargs)
else:
task_lr = task.lr or lr
parameter_groups.append({
"params": decoder_parameters,
'lr': task_lr
})
parameter_groups.append({
"params": encoder_parameters,
'lr': encoder_lr
})
no_decay = ['bias', 'LayerNorm.bias', 'LayerNorm.weight']
no_decay_parameters = set()
for n, p in model.named_parameters():
if any(nd in n for nd in no_decay):
no_decay_parameters.add(p)
no_decay_by_lr = defaultdict(list)
for group in parameter_groups:
_lr = group['lr']
ps = group['params']
group['params'] = decay_parameters = []
group['weight_decay'] = weight_decay
for p in ps:
if p in no_decay_parameters:
no_decay_by_lr[_lr].append(p)
else:
decay_parameters.append(p)
for _lr, ps in no_decay_by_lr.items():
parameter_groups.append({
"params": ps,
'lr': _lr,
'weight_decay': 0.0
})
# noinspection PyTypeChecker
encoder_optimizer = optimization.AdamW(
parameter_groups,
lr=lr,
weight_decay=weight_decay,
eps=adam_epsilon,
)
encoder_scheduler = optimization.get_linear_schedule_with_warmup(
encoder_optimizer, num_training_steps * warmup_steps,
num_training_steps)
return encoder_optimizer, encoder_scheduler, decoder_optimizers
def build_optimizer_for_pretrained(model: torch.nn.Module,
pretrained: torch.nn.Module,
lr=1e-5,
weight_decay=0.01,
eps=1e-8,
transformer_lr=None,
transformer_weight_decay=None,
no_decay=('bias', 'LayerNorm.bias',
'LayerNorm.weight'),
**kwargs):
if transformer_lr is None:
transformer_lr = lr
if transformer_weight_decay is None:
transformer_weight_decay = weight_decay
params = defaultdict(lambda: defaultdict(list))
pretrained = set(pretrained.parameters())
if isinstance(no_decay, tuple):
def no_decay_fn(name):
return any(nd in name for nd in no_decay)
else:
assert callable(
no_decay), 'no_decay has to be callable or a tuple of str'
no_decay_fn = no_decay
for n, p in model.named_parameters():
is_pretrained = 'pretrained' if p in pretrained else 'non_pretrained'
is_no_decay = 'no_decay' if no_decay_fn(n) else 'decay'
params[is_pretrained][is_no_decay].append(p)
grouped_parameters = [
{
'params': params['pretrained']['decay'],
'weight_decay': transformer_weight_decay,
'lr': transformer_lr
},
{
'params': params['pretrained']['no_decay'],
'weight_decay': 0.0,
'lr': transformer_lr
},
{
'params': params['non_pretrained']['decay'],
'weight_decay': weight_decay,
'lr': lr
},
{
'params': params['non_pretrained']['no_decay'],
'weight_decay': 0.0,
'lr': lr
},
]
return optimization.AdamW(grouped_parameters,
lr=lr,
weight_decay=weight_decay,
eps=eps,
**kwargs)
