lightning/pytorch_lightning/trainer/logging.py

202 lines
7.1 KiB
Python

# Copyright The PyTorch Lightning team.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from abc import ABC
import inspect
from typing import Union, Mapping
import torch
from pytorch_lightning.loggers import LightningLoggerBase
from pytorch_lightning.utilities.memory import recursive_detach
from pytorch_lightning.utilities.distributed import rank_zero_warn
class TrainerLoggingMixin(ABC):
# this is just a summary on variables used in this abstract class,
# the proper values/initialisation should be done in child class
current_epoch: int
on_gpu: bool
log_gpu_memory: ...
logger: Union[LightningLoggerBase, bool]
global_step: int
global_rank: int
use_dp: bool
use_ddp2: bool
default_root_dir: str
slurm_job_id: int
num_gpus: int
logged_metrics: ...
def metrics_to_scalars(self, metrics):
new_metrics = {}
for k, v in metrics.items():
if isinstance(v, torch.Tensor):
v = v.item()
if isinstance(v, dict):
v = self.metrics_to_scalars(v)
new_metrics[k] = v
return new_metrics
def process_dict_result(self, output, train=False):
"""Reduces output according to the training mode.
Separates loss from logging and progress bar metrics
"""
# --------------------
# WARN DEPRECATED KEYS
# --------------------
# TODO: 1.0.0 remove
if isinstance(output, dict):
for k, v in output.items():
if k in ['log', 'progress_bar']:
m = inspect.cleandoc(
f"""The {{{k}:dict keyword}} was deprecated in 0.9.1 and will be removed in 1.0.0
Please use self.log(...) inside the lightningModule instead.
# log on a step or aggregate epoch metric to the logger and/or progress bar
# (inside LightningModule)
self.log('train_loss', loss, on_step=True, on_epoch=True, prog_bar=True)
""")
rank_zero_warn(m)
# --------------------------
# handle single scalar only
# --------------------------
# single scalar returned from a xx_step
if isinstance(output, torch.Tensor):
progress_bar_metrics = {}
log_metrics = {}
callback_metrics = {}
hiddens = None
return output, progress_bar_metrics, log_metrics, callback_metrics, hiddens
# ---------------
# EXTRACT CALLBACK KEYS
# ---------------
# all keys not progress_bar or log are candidates for callbacks
callback_metrics = {}
if isinstance(output, Mapping):
for k, v in output.items():
if k not in ['progress_bar', 'log', 'hiddens']:
callback_metrics[k] = v
if train and (self.use_dp or self.use_ddp2):
num_gpus = self.num_gpus
callback_metrics = self.reduce_distributed_output(callback_metrics, num_gpus)
# ---------------
# EXTRACT PROGRESS BAR KEYS
# ---------------
try:
progress_output = output['progress_bar']
# reduce progress metrics for progress bar when using dp
if train and (self.use_dp or self.use_ddp2):
num_gpus = self.num_gpus
progress_output = self.reduce_distributed_output(progress_output, num_gpus)
progress_bar_metrics = progress_output
# todo: specify the possible exception
except Exception:
progress_bar_metrics = {}
# ---------------
# EXTRACT LOGGING KEYS
# ---------------
# extract metrics to log to experiment
try:
log_output = output['log']
# reduce progress metrics for progress bar when using dp
if train and (self.use_dp or self.use_ddp2):
num_gpus = self.num_gpus
log_output = self.reduce_distributed_output(log_output, num_gpus)
log_metrics = log_output
# todo: specify the possible exception
except Exception:
log_metrics = {}
# ---------------
# EXTRACT LOSS
# ---------------
# if output dict doesn't have the keyword loss
# then assume the output=loss if scalar
loss = None
if train:
try:
loss = output['loss']
# todo: specify the possible exception
except Exception as exp:
if isinstance(output, torch.Tensor):
loss = output
else:
raise RuntimeError(
'No `loss` value in the dictionary returned from `model.training_step()`.'
) from exp
# when using dp need to reduce the loss
if self.use_dp or self.use_ddp2:
loss = self.reduce_distributed_output(loss, self.num_gpus)
# ---------------
# EXTRACT HIDDEN
# ---------------
hiddens = output.get('hiddens', None) if isinstance(output, Mapping) else None
# use every metric passed in as a candidate for callback
callback_metrics.update(progress_bar_metrics)
callback_metrics.update(log_metrics)
# detach all metrics for callbacks to prevent memory leaks
# no .item() because it will slow things down
callback_metrics = recursive_detach(callback_metrics)
progress_bar_metrics = recursive_detach(progress_bar_metrics)
log_metrics = recursive_detach(log_metrics)
return loss, progress_bar_metrics, log_metrics, callback_metrics, hiddens
def reduce_distributed_output(self, output, num_gpus):
if num_gpus <= 1:
return output
# when using DP, we get one output per gpu
# average outputs and return
if isinstance(output, torch.Tensor):
return output.mean()
for k, v in output.items():
# recurse on nested dics
if isinstance(output[k], dict):
output[k] = self.reduce_distributed_output(output[k], num_gpus)
# compute the average of scalars
elif isinstance(output[k], list):
output[k] = sum(output[k]) / len(output[k])
# do nothing when there's a scalar
elif isinstance(output[k], torch.Tensor) and output[k].dim() == 0:
pass
# do not reduce metrics that have batch size > num gpus
elif output[k].size(0) <= num_gpus:
output[k] = torch.mean(output[k])
return output