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train_pnf.py
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train_pnf.py
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#!/usr/bin/env python3
import os
import sys
import torch
import numpy as np
import tensorflow as tf
from tqdm import tqdm
from torch.utils.tensorboard import SummaryWriter
from models.losses import cross_entropy_loss, prototype_loss
from models.model_utils import (CheckPointer, UniformStepLR,
CosineAnnealRestartLR, ExpDecayLR)
from data.meta_dataset_reader import (MetaDatasetBatchReader,
MetaDatasetEpisodeReader)
from models.model_helpers import get_model, get_optimizer
from utils import Accumulator
from config import args
def train():
# initialize datasets and loaders
trainsets, valsets, testsets = args['data.train'], args['data.val'], args['data.test']
train_loader = MetaDatasetBatchReader('train', trainsets, valsets, testsets,
batch_size=args['train.batch_size'])
val_loader = MetaDatasetEpisodeReader('val', trainsets, valsets, testsets)
# initialize model and optimizer
num_train_classes = sum(list(train_loader.dataset_to_n_cats.values()))
model = get_model(num_train_classes, args)
optimizer = get_optimizer(model, args, params=model.get_parameters())
# Restoring the last checkpoint
checkpointer = CheckPointer(args, model, optimizer=optimizer)
if os.path.isfile(checkpointer.last_ckpt) and args['train.resume']:
start_iter, best_val_loss, best_val_acc =\
checkpointer.restore_model(ckpt='last', strict=False)
else:
print('No checkpoint restoration')
best_val_loss = 999999999
best_val_acc = start_iter = 0
# define learning rate policy
if args['train.lr_policy'] == "step":
lr_manager = UniformStepLR(optimizer, args, start_iter)
elif "exp_decay" in args['train.lr_policy']:
lr_manager = ExpDecayLR(optimizer, args, start_iter)
elif "cosine" in args['train.lr_policy']:
lr_manager = CosineAnnealRestartLR(optimizer, args, start_iter)
# defining the summary writer
writer = SummaryWriter(checkpointer.model_path)
# Training loop
max_iter = args['train.max_iter']
epoch_loss = {name: [] for name in trainsets}
epoch_acc = {name: [] for name in trainsets}
config = tf.compat.v1.ConfigProto()
config.gpu_options.allow_growth = True
with tf.compat.v1.Session(config=config) as session:
for i in tqdm(range(max_iter)):
if i < start_iter:
continue
optimizer.zero_grad()
sample = train_loader.get_train_batch(session)
batch_dataset = sample['dataset_name']
dataset_id = sample['dataset_ids'][0].detach().cpu().item()
logits = model.forward(sample['images'])
labels = sample['labels']
batch_loss, stats_dict, _ = cross_entropy_loss(logits, labels)
epoch_loss[batch_dataset].append(stats_dict['loss'])
epoch_acc[batch_dataset].append(stats_dict['acc'])
batch_loss.backward()
optimizer.step()
lr_manager.step(i)
if (i + 1) % 200 == 0:
for dataset_name in trainsets:
writer.add_scalar(f"loss/{dataset_name}-train_acc",
np.mean(epoch_loss[dataset_name]), i)
writer.add_scalar(f"accuracy/{dataset_name}-train_acc",
np.mean(epoch_acc[dataset_name]), i)
epoch_loss[dataset_name], epoch_acc[dataset_name] = [], []
writer.add_scalar('learning_rate',
optimizer.param_groups[0]['lr'], i)
# Evaluation inside the training loop
if (i + 1) % args['train.eval_freq'] == 0:
model.eval()
dataset_accs, dataset_losses = [], []
for valset in valsets:
dataset_id = train_loader.dataset_name_to_dataset_id[valset]
val_losses, val_accs = [], []
for j in tqdm(range(args['train.eval_size'])):
with torch.no_grad():
sample = val_loader.get_validation_task(session, valset)
context_features = model.embed(sample['context_images'])
target_features = model.embed(sample['target_images'])
context_labels = sample['context_labels']
target_labels = sample['target_labels']
_, stats_dict, _ = prototype_loss(context_features, context_labels,
target_features, target_labels)
val_losses.append(stats_dict['loss'])
val_accs.append(stats_dict['acc'])
# write summaries per validation set
dataset_acc, dataset_loss = np.mean(val_accs) * 100, np.mean(val_losses)
dataset_accs.append(dataset_acc)
dataset_losses.append(dataset_loss)
writer.add_scalar(f"loss/{valset}/val_loss", dataset_loss, i)
writer.add_scalar(f"accuracy/{valset}/val_acc", dataset_acc, i)
print(f"{valset}: val_acc {dataset_acc:.2f}%, val_loss {dataset_loss:.3f}")
# write summaries averaged over datasets
avg_val_loss, avg_val_acc = np.mean(dataset_losses), np.mean(dataset_accs)
writer.add_scalar(f"loss/avg_val_loss", avg_val_loss, i)
writer.add_scalar(f"accuracy/avg_val_acc", avg_val_acc, i)
# saving checkpoints
if avg_val_acc > best_val_acc:
best_val_loss, best_val_acc = avg_val_loss, avg_val_acc
is_best = True
print('Best model so far!')
else:
is_best = False
checkpointer.save_checkpoint(i, best_val_acc, best_val_loss,
is_best, optimizer=optimizer,
state_dict=model.get_state_dict())
model.train()
print(f"Trained and evaluated at {i}")
writer.close()
if start_iter < max_iter:
print(f"""Done training with best_mean_val_loss: {best_val_loss:.3f}, best_avg_val_acc: {best_val_acc:.2f}%""")
else:
print(f"""No training happened. Loaded checkpoint at {start_iter}, while max_iter was {max_iter}""")
if __name__ == '__main__':
train()