def train_model_val(model, dataloaders, criterion, optimizer, scheduler, epochs=50):
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
model = model.to(device)
since = time.time()
logger = Logger(log_dir="./logs")
# switching optimizer after a certain thresh
switched_opt = False
# Here we store the best model
dirname = os.path.dirname(__file__)
wts_filename = os.path.join(dirname, './checkpoints/just_trained.spth')
model_filename = os.path.join(dirname, './models/just_trained.pth')
best_model_wts = copy.deepcopy(model.state_dict())
# Statistics
best_acc = 0.0
best_loss = 100.0
total_step = 0.0
model.train(True) # Set model to training mode
for epoch in range(epochs):
print('Epoch {}/{}'.format(epoch+1, epochs))
print('-' * 10)
# Each epoch has a training and validation phase
for phase in ['train', 'val']:
if phase == 'train':
scheduler.step()
model.train(True) # Set model to training mode
else:
model.train(False) # Set model to evaluate mode
running_loss = 0.0
running_corrects = 0
total = 0
# Iterate over data.
for i, batch in enumerate(dataloaders[phase]):
# get the inputs
inputs, labels = batch
inputs, labels = inputs.to(device), labels.to(device)
# zero the parameter gradients
optimizer.zero_grad()
# forward
outputs = model(inputs)
_, preds = torch.max(outputs, 1)
loss = criterion(outputs, labels)
# backward + optimize only if in training phase
if phase == 'train':
loss.backward()
optimizer.step()
# statistics
# loss * batch_size
running_loss += loss.item()
running_corrects += torch.sum(preds == labels.data)
total += inputs.size(0)
# len(batch) or dataloader[phase].batch_size
batch_size = inputs.size(0)
epoch_loss = running_loss / i+1
epoch_acc = 100 * running_corrects/total
print('{} Loss: {:.4f} Acc: {:.4f}'.format(
phase, epoch_loss, epoch_acc))
# progress_bar(batch_idx, len(trainloader), 'Loss: %.3f | Acc: %.3f%% (%d/%d)'
# % (train_loss/(batch_idx+1), 100.*correct/total, correct, total))
if phase == 'train':
train_loss_to_plot = epoch_loss
else:
# ============ Logging ============#
# (1) Log the scalar values
metrics = {
'loss': train_loss_to_plot, # train loss
'accuracy': epoch_acc # val accuracy
}
# (2) Log CSV file
logger.log_csv(epoch, metrics['accuracy'], metrics['loss'])
# (3) Tensorboard specific logging
logger.tensorboard_log(epoch, model, metrics)
# deep copy the model
if phase == 'val' and epoch_acc > best_acc:
print('Acc improved from %.3f to %.3f'
% (best_acc, epoch_acc))
logger.log_test(epoch, epoch_acc)
print('Saving model to ' + model_filename + "...\n")
best_acc = epoch_acc
best_model_wts = copy.deepcopy(model.state_dict())
torch.save(model.state_dict(), wts_filename)
torch.save(model, model_filename)
# Switch to SGD + Nesterov
if train_loss_to_plot <= 0.6 and not switched_opt:
print('Switching to SGD wt Nesterov Momentum...')
optimizer = optim.SGD(model.parameters(),
lr=1e-4, momentum=0.9, nesterov=True)
switched_opt = True
## EARLY STOPPING ##
if train_loss_to_plot <= 0.150 and epoch >= 5:
print('EARLY STOPPING!')
print(train_loss_to_plot)
time_elapsed = time.time() - since
print('Training complete in {:.0f}m {:.0f}s'.format(
time_elapsed // 60, time_elapsed % 60))
print('Best val Acc: {:4f}'.format(best_acc))
# load best model weights
model.load_state_dict(best_model_wts)
return model
print()
time_elapsed = time.time() - since
print('Training complete in {:.0f}m {:.0f}s'.format(
time_elapsed // 60, time_elapsed % 60))
print('Best val Acc: {:4f}'.format(best_acc))
# load best model weights
model.load_state_dict(best_model_wts)
return model
def train_test_model(dataloader, model, criterion, optimizer, scheduler, loss_threshold=0.3, epochs=25):
trainloader = dataloader['train']
testloader = dataloader['test']
logger = Logger(log_dir='./logs')
device = ("cuda" if torch.cuda.is_available() else "cpu")
model = model.to(device)
since = time.time()
# switching optimizer after a certain thresh
switched_opt = False
# Here we store the best model
dirname = os.path.dirname(__file__)
wts_filename = 'checkpoints/just_trained.pth.tar'
model_filename = 'checkpoints/best.pth'
best_model_wts = copy.deepcopy(model.state_dict())
# Statistics
# train
best_acc = 0.0
best_loss = 100.0
total_step = 0.0
local_minima_loss = 0.0
counter = 0
# test
best_test_acc = 0.0
current_test_acc = 0.0
plateau_counter = 0
model.train(True) # Set model to training mode
for epoch in range(epochs):
print('Epoch {}/{}'.format(epoch + 1, epochs))
print('-' * 10)
# scheduler.step()
running_loss = 0.0
running_corrects = 0
# Iterate over data.
for step, data in enumerate(trainloader, 0):
# get the input batch
inputs, labels = data
inputs, labels = inputs.to(device), labels.to(device)
# zero the parameter gradients
optimizer.zero_grad()
# forward - compute loss - backward step - update step
outputs = model(inputs)
loss = criterion(outputs, labels)
loss.backward()
optimizer.step()
# Compute stats
# preds = outputs.cpu().data.max(1)[1]
_, preds = torch.max(outputs.data, 1)
# running_corrects = (labels.float() == preds.float().squeeze().mean())
# loss * batch_size
running_loss += loss.item()
# compute accuracy
# .item() for pytorch >= 0.4
batch_correct = preds.eq(labels.data).sum().item()
batch_size = labels.size(0)
running_corrects += batch_correct / batch_size
# running_corrects += torch.sum(preds == labels.data)
progress_bar(step, len(trainloader), 'Loss: %.3f | Acc: %.3f (%d/%d)'
% (running_loss / 1000, running_corrects / 1000, batch_correct, batch_size))
if step % 1000 == 999: # print every 1000 mini-batches
step_loss = running_loss / 1000
step_acc = running_corrects / 1000
print('Epoch: {} Step: {} Loss: {:.3f} Acc: {:.3f}'.format(
epoch + 1, step + 1, step_loss, step_acc))
# print('[%d, %5d] loss: %.3f' % (epoch + 1, step + 1,
# step_loss))
total_step += step + 1
# ============ Logging ============#
# (1) Log the scalar values
metrics = {
'loss': step_loss,
'accuracy': step_acc
}
# (2) Log CSV file
print('logging...')
logger.log_csv(
total_step, metrics['accuracy'], metrics['loss'])
# (3) Tensorboard specific logging
logger.tensorboard_log(total_step, model, metrics)
# save checkpoint
save_checkpoint(model.state_dict(),
(step_loss < best_loss), 'checkpoints/')
# for each epoch, save best model
if best_loss > step_loss:
print('loss improved from %.3f to %.3f'
% (best_loss, step_loss))
best_loss = step_loss
best_acc = step_acc
best_model_wts = copy.deepcopy(model.state_dict())
# Every X epochs, write model to files
if((epoch + 1) % 2 == 1 or epoch == 49):
print('Saving model to ' +
model_filename + "...\n")
# torch.save(best_model_wts, os.path.join(
# dirname, wts_filename))
torch.save(model, os.path.join(
dirname, model_filename))
# Switch to SGD + Nesterov
if best_loss <= 0.6 and not switched_opt:
print('Switching to SGD wt Nesterov Momentum...')
optimizer = optim.SGD(
model.parameters(), lr=1e-4, momentum=0.9, nesterov=True)
switched_opt = True
else:
# if it stagnates in local minima
local_minima_loss = best_loss
if step_loss - local_minima_loss < 0.020:
counter += 1
if counter >= 5 and not switched_opt:
print(
'Stuck in local minima. Switching to SGD wt Nesterov Momentum...')
optimizer = optim.SGD(
model.parameters(), lr=1e-4, momentum=0.9, nesterov=True)
switched_opt = True
# Every 5 epochs, test model
if((epoch + 1) % 5 == 0):
print("Testing...")
current_test_acc = quick_test_cifar(testloader, model)
# update accuracy wt. ternary assignment
best_test_acc = current_test_acc if current_test_acc > best_test_acc else best_test_acc
if current_test_acc > best_test_acc:
best_test_acc = current_test_acc
# zero the plateau counter
plateau_counter = 0
else:
plateau_counter += 1
# log test val
logger.log_test(total_step, best_test_acc)
# switch back model
model.train(True) # Set model to training mode
model.cuda()
## EARLY STOPPING ##
if (plateau_counter > 5) or (best_loss <= loss_threshold and epoch >= 5):
print('EARLY STOPPING!')
time_elapsed = time.time() - since
print('Training complete in {:.0f}m {:.0f}s'.format(
time_elapsed // 60, time_elapsed % 60))
print('Best val Acc: {:4f}'.format(best_acc))
# load best model weights
model.load_state_dict(best_model_wts)
return model
# Reset running loss for next iteration
running_loss = 0.0
print()
time_elapsed = time.time() - since
print('Training complete in {:.0f}m {:.0f}s'.format(
time_elapsed // 60, time_elapsed % 60))
print('Best val Acc: {:4f}'.format(best_acc))
# load best model weights
model.load_state_dict(best_model_wts)
return model
