lightning/pytorch_lightning/models/trainer.py

490 lines
17 KiB
Python

import torch
import tqdm
import numpy as np
from pytorch_lightning.root_module.memory import get_gpu_memory_map
import traceback
from pytorch_lightning.root_module.model_saving import TrainerIO
from torch.optim.lr_scheduler import MultiStepLR
from pytorch_lightning.pt_overrides.override_data_parallel import LightningDataParallel
import pdb
try:
from apex import amp
APEX_AVAILABLE = True
except ModuleNotFoundError:
APEX_AVAILABLE = False
def reduce_distributed_output(output, nb_gpus):
for k, v in output.items():
# recurse on nested dics
if isinstance(output[k], dict):
output[k] = reduce_distributed_output(output[k], nb_gpus)
# reduce only metrics that have the same nb of gpus
elif output[k].size(0) == nb_gpus:
reduced = torch.mean(output[k])
output[k] = reduced
return output
class Trainer(TrainerIO):
def __init__(self,
experiment,
checkpoint_callback, early_stop_callback,
cluster=None,
process_position=0,
current_gpu_name=0,
gpus=None,
enable_tqdm=True,
overfit_pct=0.0,
track_grad_norm=-1,
check_val_every_n_epoch=1,
fast_dev_run=False,
accumulate_grad_batches=1,
enable_early_stop=True, max_nb_epochs=5, min_nb_epochs=1,
train_percent_check=1.0, val_percent_check=1.0, test_percent_check=1.0, val_check_interval=0.95,
log_save_interval=1, add_log_row_interval=1,
lr_scheduler_milestones=None,
use_amp=False,
check_grad_nans=False,
amp_level='O2',
nb_sanity_val_steps=5):
# Transfer params
self.check_val_every_n_epoch = check_val_every_n_epoch
self.enable_early_stop = enable_early_stop
self.track_grad_norm = track_grad_norm
self.fast_dev_run = fast_dev_run
self.on_gpu = gpus is not None and torch.cuda.is_available()
self.enable_tqdm = enable_tqdm
self.experiment = experiment
self.exp_save_path = experiment.get_data_path(experiment.name, experiment.version)
self.cluster = cluster
self.process_position = process_position
self.current_gpu_name = current_gpu_name
self.checkpoint_callback = checkpoint_callback
self.checkpoint_callback.save_function = self.save_checkpoint
self.early_stop = early_stop_callback
self.model = None
self.max_nb_epochs = max_nb_epochs
self.accumulate_grad_batches = accumulate_grad_batches
self.early_stop_callback = early_stop_callback
self.min_nb_epochs = min_nb_epochs
self.nb_sanity_val_steps = nb_sanity_val_steps
self.lr_scheduler_milestones = [] if lr_scheduler_milestones is None else [int(x.strip()) for x in lr_scheduler_milestones.split(',')]
self.lr_schedulers = []
self.amp_level = amp_level
self.check_grad_nans = check_grad_nans
self.data_parallel_device_ids = gpus
self.data_parallel = gpus is not None and len(gpus) > 0
# training state
self.optimizers = None
self.prog_bar = None
self.global_step = 0
self.current_epoch = 0
self.total_batches = 0
# logging
self.log_save_interval = log_save_interval
self.val_check_interval = val_check_interval
self.add_log_row_interval = add_log_row_interval
# dataloaders
self.tng_dataloader = None
self.test_dataloader = None
self.val_dataloader = None
# how much of the data to use
self.__determine_data_use_amount(train_percent_check, val_percent_check, test_percent_check, overfit_pct)
print('gpu available: {}, used: {}'.format(torch.cuda.is_available(), self.on_gpu))
# apex test
self.use_amp = use_amp and APEX_AVAILABLE
if self.use_amp:
print('using 16bit precision')
def __determine_data_use_amount(self, train_percent_check, val_percent_check, test_percent_check, overfit_pct):
"""
Use less data for debugging purposes
"""
self.train_percent_check = train_percent_check
self.val_percent_check = val_percent_check
self.test_percent_check = test_percent_check
if overfit_pct > 0:
self.train_percent_check = overfit_pct
self.val_percent_check = overfit_pct
self.test_percent_check = overfit_pct
def __is_function_implemented(self, f_name):
f_op = getattr(self.model, f_name, None)
return callable(f_op)
@property
def __tng_tqdm_dic(self):
tqdm_dic = {
'tng_loss': '{0:.3f}'.format(self.avg_loss),
'gpu': '{}'.format(self.current_gpu_name),
'v_nb': '{}'.format(self.experiment.version),
'epoch': '{}'.format(self.current_epoch),
'batch_nb':'{}'.format(self.batch_nb),
}
tqdm_dic.update(self.tqdm_metrics)
return tqdm_dic
def __layout_bookeeping(self, model):
# training bookeeping
self.total_batch_nb = 0
self.running_loss = []
self.avg_loss = 0
self.batch_nb = 0
self.tqdm_metrics = {}
# determine number of training batches
self.nb_tng_batches = model.nb_batches(self.tng_dataloader)
self.nb_tng_batches = int(self.nb_tng_batches * self.train_percent_check)
# determine number of validation batches
self.nb_val_batches = model.nb_batches(self.val_dataloader)
self.nb_val_batches = int(self.nb_val_batches * self.val_percent_check)
self.nb_val_batches = max(1, self.nb_val_batches)
self.nb_val_batches = self.nb_val_batches
# determine number of test batches
self.nb_test_batches = model.nb_batches(self.test_dataloader)
self.nb_test_batches = int(self.nb_test_batches * self.test_percent_check)
# determine when to check validation
self.val_check_batch = int(self.nb_tng_batches * self.val_check_interval)
def __add_tqdm_metrics(self, metrics):
for k, v in metrics.items():
self.tqdm_metrics[k] = v
def validate(self, model, dataloader, max_batches):
"""
Run validation code
:param model: PT model
:param dataloader: PT dataloader
:param max_batches: Scalar
:return:
"""
print('validating...')
# enable eval mode
model.zero_grad()
model.eval()
model.from_lightning = True
# disable gradients to save memory
torch.set_grad_enabled(False)
# bookkeeping
outputs = []
# run training
for batch_i, data_batch in enumerate(dataloader):
if data_batch is None:
continue
# stop short when on fast dev run
if max_batches is not None and batch_i >= max_batches:
break
# -----------------
# RUN VALIDATION STEP
# -----------------
if self.data_parallel:
output = model(data_batch, batch_i)
output = reduce_distributed_output(output, len(self.data_parallel_device_ids))
else:
output = model.validation_step(data_batch, batch_i)
outputs.append(output)
# batch done
if self.enable_tqdm and self.prog_bar is not None:
self.prog_bar.update(1)
# give model a chance to do something with the outputs
if self.data_parallel:
val_results = model.module.validation_end(outputs)
else:
val_results = model.validation_end(outputs)
# enable train mode again
model.train()
# enable gradients to save memory
torch.set_grad_enabled(True)
return val_results
def __get_dataloaders(self, model):
"""
Dataloaders are provided by the model
:param model:
:return:
"""
self.tng_dataloader = model.tng_dataloader
self.test_dataloader = model.test_dataloader
self.val_dataloader = model.val_dataloader
# -----------------------------
# MODEL TRAINING
# -----------------------------
def fit(self, model):
model.trainer = self
# transfer data loaders from model
self.__get_dataloaders(model)
# init training constants
self.__layout_bookeeping(model)
# CHOOSE OPTIMIZER
# filter out the weights that were done on gpu so we can load on good old cpus
self.optimizers = model.configure_optimizers()
if self.use_amp:
# An example
model, optimizer = amp.initialize(
model, self.optimizers[0], opt_level=self.amp_level,
)
self.optimizers[0] = optimizer
model.trainer = self
# add lr schedulers
if self.lr_scheduler_milestones is not None:
for optimizer in self.optimizers:
scheduler = MultiStepLR(optimizer, self.lr_scheduler_milestones)
self.lr_schedulers.append(scheduler)
# print model summary
model.summarize()
# put on gpu if needed
if self.on_gpu:
model = LightningDataParallel(model, device_ids=self.data_parallel_device_ids)
# run tiny validation to make sure program won't crash during val
_ = self.validate(model, self.val_dataloader, max_batches=self.nb_sanity_val_steps)
# save exp to get started
self.experiment.save()
# enable cluster checkpointing
if self.cluster is not None:
self.enable_auto_hpc_walltime_manager()
# ---------------------------
# CORE TRAINING LOOP
# ---------------------------
self.model = model
self.__train()
def __train(self):
# run all epochs
for epoch_nb in range(self.current_epoch, self.max_nb_epochs):
# update the lr scheduler
for lr_scheduler in self.lr_schedulers:
lr_scheduler.step()
self.model.current_epoch = epoch_nb
# hook
if self.__is_function_implemented('on_epoch_start'):
self.model.on_epoch_start()
self.current_epoch = epoch_nb
self.total_batches = self.nb_tng_batches + self.nb_val_batches
self.batch_loss_value = 0 # accumulated grads
# init progbar when requested
if self.enable_tqdm:
self.prog_bar = tqdm.tqdm(range(self.total_batches), position=self.process_position)
for batch_nb, data_batch in enumerate(self.tng_dataloader):
self.batch_nb = batch_nb
self.global_step += 1
self.model.global_step = self.global_step
# stop when the flag is changed or we've gone past the amount requested in the batches
self.total_batch_nb += 1
met_batch_limit = batch_nb > self.nb_tng_batches
if met_batch_limit:
break
# ---------------
# RUN TRAIN STEP
# ---------------
batch_result = self.__run_tng_batch(data_batch, batch_nb)
early_stop_epoch = batch_result == -1
# ---------------
# RUN VAL STEP
# ---------------
is_val_check_batch = (batch_nb + 1) % self.val_check_batch == 0
if self.fast_dev_run or is_val_check_batch or early_stop_epoch:
self.__run_validation()
# when batch should be saved
if (batch_nb + 1) % self.log_save_interval == 0 or early_stop_epoch:
self.experiment.save()
# when metrics should be logged
if batch_nb % self.add_log_row_interval == 0 or early_stop_epoch:
# count items in memory
# nb_params, nb_tensors = count_mem_items()
metrics = self.model.update_tng_log_metrics(self.__tng_tqdm_dic)
# add gpu memory
if self.on_gpu:
mem_map = get_gpu_memory_map()
metrics.update(mem_map)
# add norms
if self.track_grad_norm > 0:
grad_norm_dic = self.model.grad_norm(self.track_grad_norm)
metrics.update(grad_norm_dic)
# log metrics
self.experiment.log(metrics)
self.experiment.save()
# hook
if self.__is_function_implemented('on_batch_end'):
self.model.on_batch_end()
# end epoch early
if early_stop_epoch:
break
# hook
if self.__is_function_implemented('on_epoch_end'):
self.model.on_epoch_end()
# early stopping
if self.enable_early_stop:
should_stop = self.early_stop_callback.on_epoch_end(epoch=epoch_nb, logs=self.__tng_tqdm_dic)
met_min_epochs = epoch_nb > self.min_nb_epochs
# stop training
stop = should_stop and met_min_epochs
if stop:
return
def __run_tng_batch(self, data_batch, batch_nb):
if data_batch is None:
return 0
# hook
if self.__is_function_implemented('on_batch_start'):
response = self.model.on_batch_start(data_batch)
if response == -1:
return -1
if self.enable_tqdm:
self.prog_bar.update(1)
# forward pass
# return a scalar value and a dic with tqdm metrics
pdb.set_trace()
if self.data_parallel:
output = self.model(data_batch, batch_nb)
output = reduce_distributed_output(output, len(self.data_parallel_device_ids))
else:
output = self.mode(data_batch, batch_nb)
loss, model_specific_tqdm_metrics_dic = self.model.training_step(data_batch, batch_nb)
self.__add_tqdm_metrics(model_specific_tqdm_metrics_dic)
# backward pass
if self.use_amp:
for optimizer in self.optimizers:
with amp.scale_loss(loss, optimizer) as scaled_loss:
scaled_loss.backward()
else:
loss.backward()
if self.check_grad_nans:
for param in self.model.parameters():
print(param.grad.float().sum())
self.batch_loss_value += loss.item()
# gradient update with accumulated gradients
if (self.batch_nb + 1) % self.accumulate_grad_batches == 0:
# update gradients across all optimizers
for optimizer in self.optimizers:
optimizer.step()
# clear gradients
optimizer.zero_grad()
# queuing loss across batches blows it up proportionally... divide out the number accumulated
self.batch_loss_value = self.batch_loss_value / self.accumulate_grad_batches
# track loss
self.running_loss.append(self.batch_loss_value)
self.batch_loss_value = 0
self.avg_loss = np.mean(self.running_loss[-100:])
# update progbar
if self.enable_tqdm:
# add model specific metrics
tqdm_metrics = self.__tng_tqdm_dic
self.prog_bar.set_postfix(**tqdm_metrics)
# activate batch end hook
if self.__is_function_implemented('on_batch_end'):
self.model.on_batch_end()
return 0
def __run_validation(self):
# decide if can check epochs
can_check_epoch = (self.current_epoch + 1) % self.check_val_every_n_epoch == 0
if self.fast_dev_run:
print('skipping to check performance bc of --fast_dev_run')
elif not can_check_epoch:
return
try:
# hook
if self.__is_function_implemented('on_pre_performance_check'):
self.model.on_pre_performance_check()
# use full val set on end of epoch
# use a small portion otherwise
max_batches = None if not self.fast_dev_run else 1
model_specific_tqdm_metrics_dic = self.validate(
self.model,
self.val_dataloader,
max_batches
)
self.__add_tqdm_metrics(model_specific_tqdm_metrics_dic)
# hook
if self.__is_function_implemented('on_post_performance_check'):
self.model.on_post_performance_check()
except Exception as e:
print(e)
print(traceback.print_exc())
if self.enable_tqdm:
# add model specific metrics
tqdm_metrics = self.__tng_tqdm_dic
self.prog_bar.set_postfix(**tqdm_metrics)
# model checkpointing
print('save callback...')
self.checkpoint_callback.on_epoch_end(epoch=self.current_epoch, logs=self.__tng_tqdm_dic)