def test_update_losses(self):
l1 = RALoss('l1', 5)
l2 = RALoss('l2', 5)
losses = [(l1, 10), (l2, 20)]
utils.update_losses(losses)
utils.update_losses(losses)
self.assertEqual(l1.get_history(), [10, 10])
self.assertEqual(l2.get_history(), [20, 20])
def test_get_value(self):
l = RALoss('name', 3)
dat = [0, 1, 2, 3, 4, 5, 6, 7]
for x in dat:
l.update(x)
self.assertEqual(dat, l.get_history())
self.assertEqual(6.0, l.get_value())
self.assertEqual(3.0, l.get_value(i=4))
def train_vae(vae, itr_train, itr_valid, params):
"""Train a VAE.
Args:
vae (VAE): a VAE.
itr_train (Iterator): an iterator over training data.
itr_valid (Iterator): an iterator over validation data.
params (dict): flags for training.
"""
run_avg_len = params['run_avg_len']
max_steps = params['max_steps']
print_freq = params['print_freq']
# RALoss is an object which tracks the running average of a loss.
ra_loss = RALoss('elbo', run_avg_len)
ra_kl = RALoss('kl', run_avg_len)
ra_recon = RALoss('recon', run_avg_len)
ra_trainloss = RALoss('train-elbo', run_avg_len)
min_val_loss = sys.maxsize
min_val_step = 0
opt = tf.train.AdamOptimizer(learning_rate=params['lr'])
finished_training = False
start_printing = 0
for i in range(max_steps):
batch = itr_train.next()
with tf.GradientTape() as tape:
train_loss, _, _ = vae.get_loss(batch)
mean_train_loss = tf.reduce_mean(train_loss)
val_batch = itr_valid.next()
valid_loss, kl_loss, recon_loss = vae.get_loss(val_batch)
loss_list = [ra_loss, ra_kl, ra_recon, ra_trainloss]
losses = zip(loss_list, [
tf.reduce_mean(l)
for l in (valid_loss, kl_loss, recon_loss, train_loss)
])
utils.update_losses(losses)
grads = tape.gradient(mean_train_loss, vae.weights)
opt.apply_gradients(zip(grads, vae.weights))
curr_ra_loss = ra_loss.get_value()
# Early stopping: stop training when validation loss stops decreasing.
# The second condition ensures we don't checkpoint every step early on.
if curr_ra_loss < min_val_loss and \
i - min_val_step > params['patience'] / 10:
min_val_loss = curr_ra_loss
min_val_step = i
save_path, ckpt = utils.checkpoint_model(vae, params['ckptdir'])
logging.info('Step {:d}: Checkpointed to {}'.format(i, save_path))
elif i - min_val_step > params['patience'] or i == max_steps - 1:
ckpt.restore(save_path)
logging.info('Best validation loss was {:.3f} at step {:d}'
' - stopping training'.format(min_val_loss,
min_val_step))
finished_training = True
if i % print_freq == 0 or finished_training:
utils.print_losses(loss_list, i)
utils.write_losses_to_log(loss_list, range(start_printing, i + 1),
params['logdir'])
start_printing = i + 1
utils.plot_losses(params['figdir'], loss_list,
params['mpl_format'])
utils.plot_samples(params['sampledir'], vae, itr_valid,
params['mpl_format'])
if finished_training:
break
def train_classifier(clf, itr_train, itr_valid, params):
"""Train a classifier.
Args:
clf (classifier): a classifier we wish to train.
itr_train (Iterator): an iterator over training data.
itr_valid (Iterator): an iterator over validation data.
params (dict): flags for training.
"""
# Dump the parameters we used to a JSON file for reproducibility.
params_file = os.path.join(params['results_dir'], 'params.json')
utils.write_json(params_file, params)
run_avg_len = params['run_avg_len']
max_steps = params['max_steps']
print_freq = params['print_freq']
# RALoss is an object which tracks the running average of a loss.
ra_loss = RALoss('loss', run_avg_len)
ra_error = RALoss('error', run_avg_len)
ra_trainloss = RALoss('train-loss', run_avg_len)
ra_trainerr = RALoss('train-err', run_avg_len)
min_val_loss = sys.maxsize
min_val_step = 0
opt = tf.train.AdamOptimizer(learning_rate=params['lr'])
finished_training = False
start_printing = 0
for i in range(max_steps):
batch_x, batch_y = itr_train.next()
with tf.GradientTape() as tape:
train_loss, train_err = clf.get_loss(batch_x, batch_y)
mean_train_loss = tf.reduce_mean(train_loss)
val_batch_x, val_batch_y = itr_valid.next()
valid_loss, valid_err = clf.get_loss(val_batch_x, val_batch_y)
loss_list = [ra_loss, ra_error, ra_trainloss, ra_trainerr]
losses = zip(loss_list,
[tf.reduce_mean(l) for l in
(valid_loss, valid_err, train_loss, train_err)])
utils.update_losses(losses)
grads = tape.gradient(mean_train_loss, clf.weights)
opt.apply_gradients(zip(grads, clf.weights))
utils.print_losses(loss_list, i)
if params['early_stopping_metric'] == 'loss':
curr_ra_loss = ra_loss.get_value()
elif params['early_stopping_metric'] == 'error':
curr_ra_loss = ra_error.get_value()
else:
raise ValueError('Params["early_stopping_metric"] should be either "loss"'
' or "error", and it is "{}"'.format(
params['early_stopping_metric']))
if curr_ra_loss < min_val_loss and \
i - min_val_step > params['patience'] / 10:
# Early stopping: stop training when validation loss stops decreasing.
# The second condition ensures we don't checkpoint every step early on.
min_val_loss = curr_ra_loss
min_val_step = i
save_path, ckpt = utils.checkpoint_model(clf, params['ckptdir'])
logging.info('Step {:d}: Checkpointed to {}'.format(i, save_path))
elif i - min_val_step > params['patience'] or i == max_steps - 1:
ckpt.restore(save_path)
finished_training = True
logging.info('Best validation loss was {:.3f} at step {:d}'
' - stopping training'.format(min_val_loss, min_val_step))
if i % print_freq == 0 or finished_training:
utils.write_losses_to_log(loss_list, range(start_printing, i + 1),
params['logdir'])
start_printing = i + 1
utils.plot_losses(params['figdir'], loss_list, params['mpl_format'])
logging.info('Step {:d}: Wrote losses and plots'.format(i))
if finished_training:
break