def main(exp, batch_size, lr, gpu):
setproctitle(exp)
output = '../output/{}'.format(exp)
try:
os.makedirs(output)
except:
pass
os.environ['CUDA_VISIBLE_DEVICES'] = str(gpu)
loss_fn = CrossEntropyLoss()
net = OmniglotNet(10, loss_fn)
# NOTE: load weights from pre-trained model
net.load_state_dict(
torch.load('../output/maml-mnist-10way-5shot/train_iter_4500.pth'))
net.cuda()
opt = Adam(net.parameters(), lr=lr)
train_dataset = MNIST('../data/mnist/mnist_png',
transform=transforms.ToTensor())
test_dataset = MNIST('../data/mnist/mnist_png',
split='test',
transform=transforms.ToTensor())
train_loader = DataLoader(train_dataset,
batch_size=batch_size,
shuffle=True,
num_workers=1,
pin_memory=True)
val_loader = DataLoader(train_dataset,
batch_size=batch_size,
shuffle=False,
num_workers=1,
pin_memory=True)
num_epochs = 10
train_loss = []
train_acc = []
val_loss = []
val_acc = []
for epoch in range(num_epochs):
# train for 1 epoch
t_loss, t_acc, v_loss, v_acc = train(train_loader, val_loader, net,
loss_fn, opt, epoch)
train_loss += t_loss
train_acc += t_acc
val_loss += v_loss
val_acc += v_acc
# eval on the val set
np.save('{}/train_loss.npy'.format(output), np.array(train_loss))
np.save('{}/train_acc.npy'.format(output), np.array(train_acc))
np.save('{}/val_loss.npy'.format(output), np.array(val_loss))
np.save('{}/val_acc.npy'.format(output), np.array(val_acc))
def test(self):
num_in_channels = 1 if self.dataset == 'mnist' else 3
test_net = OmniglotNet(self.num_classes, self.loss_fn, num_in_channels)
mtr_loss, mtr_acc, mval_loss, mval_acc = 0.0, 0.0, 0.0, 0.0
# Select ten tasks randomly from the test set to evaluate on
for _ in range(10):
# Make a test net with same parameters as our current net
test_net.copy_weights(self.net)
if self.is_cuda:
test_net.cuda()
test_opt = SGD(test_net.parameters(), lr=self.inner_step_size)
task = self.get_task('../data/{}'.format(self.dataset),
self.num_classes,
self.num_inst,
split='test')
# Train on the train examples, using the same number of updates as in training
train_loader = get_data_loader(task,
self.inner_batch_size,
split='train')
for i in range(self.num_inner_updates):
in_, target = train_loader.__iter__().next()
loss, _ = forward_pass(test_net,
in_,
target,
is_cuda=self.is_cuda)
test_opt.zero_grad()
loss.backward()
test_opt.step()
# Evaluate the trained model on train and val examples
tloss, tacc = evaluate(test_net, train_loader)
val_loader = get_data_loader(task,
self.inner_batch_size,
split='val')
vloss, vacc = evaluate(test_net, val_loader)
mtr_loss += tloss
mtr_acc += tacc
mval_loss += vloss
mval_acc += vacc
mtr_loss = mtr_loss / 10
mtr_acc = mtr_acc / 10
mval_loss = mval_loss / 10
mval_acc = mval_acc / 10
print '-------------------------'
print 'Meta train:', mtr_loss, mtr_acc
print 'Meta val:', mval_loss, mval_acc
print '-------------------------'
del test_net
return mtr_loss, mtr_acc, mval_loss, mval_acc
def count_correct(pred, target):
''' count number of correct predictions in a batch '''
pairs = [ int(x==y) for (x, y) in zip(pred, target)]
return sum(pairs)
def train_step(task):
train_loader = get_data_loader(task)
##### Test net before training, should be random accuracy ####
print('Before training update', evaluate(net, train_loader))
for i in range(10):
loss,_ = forward(net, train_loader)
print('Loss', loss.data.cpu().numpy())
opt.zero_grad()
loss.backward()
opt.step()
print('Iter ', i, evaluate(net, train_loader))
##### Test net after training, should be better than random ####
print('After training update', evaluate(net, train_loader))
# Script
for i in range(5):
print('Run ', i)
net = OmniglotNet(num_classes, loss_fn=CrossEntropyLoss())
if torch,cuda.is_available():
net.cuda()
opt = SGD(net.parameters(), lr=0.001, momentum=0.9, weight_decay=0.0005)
#opt = Adam(net.weights.values(), lr=1)
task = OmniglotTask('/home/vashisht/data/omniglot', num_classes, num_shot)
train_step(task)
class MetaLearner(object):
def __init__(self, dataset, num_classes, num_inst, meta_batch_size,
meta_step_size, inner_batch_size, inner_step_size,
num_updates, num_inner_updates, loss_fn):
super(self.__class__, self).__init__()
self.dataset = dataset
self.num_classes = num_classes
self.num_inst = num_inst
self.meta_batch_size = meta_batch_size
self.meta_step_size = meta_step_size
self.inner_batch_size = inner_batch_size
self.inner_step_size = inner_step_size
self.num_updates = num_updates
self.num_inner_updates = num_inner_updates
self.loss_fn = loss_fn
# Make the nets
#TODO: don't actually need two nets
num_input_channels = 1 if self.dataset == 'mnist' else 3
self.net = OmniglotNet(num_classes, self.loss_fn, num_input_channels)
self.net.cuda()
self.fast_net = InnerLoop(num_classes, self.loss_fn,
self.num_inner_updates, self.inner_step_size,
self.inner_batch_size, self.meta_batch_size,
num_input_channels)
self.fast_net.cuda()
self.opt = Adam(self.net.parameters())
def get_task(self, root, n_cl, n_inst, split='train'):
if 'mnist' in root:
return MNISTTask(root, n_cl, n_inst, split)
elif 'omniglot' in root:
return OmniglotTask(root, n_cl, n_inst, split)
else:
print 'Unknown dataset'
raise (Exception)
def meta_update(self, task, ls):
print '\n Meta update \n'
loader = get_data_loader(task, self.inner_batch_size, split='val')
in_, target = loader.__iter__().next()
# We use a dummy forward / backward pass to get the correct grads into self.net
loss, out = forward_pass(self.net, in_, target)
# Unpack the list of grad dicts
gradients = {k: sum(d[k] for d in ls) for k in ls[0].keys()}
# Register a hook on each parameter in the net that replaces the current dummy grad
# with our grads accumulated across the meta-batch
hooks = []
for (k, v) in self.net.named_parameters():
def get_closure():
key = k
def replace_grad(grad):
return gradients[key]
return replace_grad
hooks.append(v.register_hook(get_closure()))
# Compute grads for current step, replace with summed gradients as defined by hook
self.opt.zero_grad()
loss.backward()
# Update the net parameters with the accumulated gradient according to optimizer
self.opt.step()
# Remove the hooks before next training phase
for h in hooks:
h.remove()
def test(self):
num_in_channels = 1 if self.dataset == 'mnist' else 3
test_net = OmniglotNet(self.num_classes, self.loss_fn, num_in_channels)
mtr_loss, mtr_acc, mval_loss, mval_acc = 0.0, 0.0, 0.0, 0.0
# Select ten tasks randomly from the test set to evaluate on
for _ in range(10):
# Make a test net with same parameters as our current net
test_net.copy_weights(self.net)
test_net.cuda()
test_opt = SGD(test_net.parameters(), lr=self.inner_step_size)
task = self.get_task('../data/{}'.format(self.dataset),
self.num_classes,
self.num_inst,
split='test')
# Train on the train examples, using the same number of updates as in training
train_loader = get_data_loader(task,
self.inner_batch_size,
split='train')
for i in range(self.num_inner_updates):
in_, target = train_loader.__iter__().next()
loss, _ = forward_pass(test_net, in_, target)
test_opt.zero_grad()
loss.backward()
test_opt.step()
# Evaluate the trained model on train and val examples
tloss, tacc = evaluate(test_net, train_loader)
val_loader = get_data_loader(task,
self.inner_batch_size,
split='val')
vloss, vacc = evaluate(test_net, val_loader)
mtr_loss += tloss
mtr_acc += tacc
mval_loss += vloss
mval_acc += vacc
mtr_loss = mtr_loss / 10
mtr_acc = mtr_acc / 10
mval_loss = mval_loss / 10
mval_acc = mval_acc / 10
print '-------------------------'
print 'Meta train:', mtr_loss, mtr_acc
print 'Meta val:', mval_loss, mval_acc
print '-------------------------'
del test_net
return mtr_loss, mtr_acc, mval_loss, mval_acc
def _train(self, exp):
''' debugging function: learn two tasks '''
task1 = self.get_task('../data/{}'.format(self.dataset),
self.num_classes, self.num_inst)
task2 = self.get_task('../data/{}'.format(self.dataset),
self.num_classes, self.num_inst)
for it in range(self.num_updates):
grads = []
for task in [task1, task2]:
# Make sure fast net always starts with base weights
self.fast_net.copy_weights(self.net)
_, g = self.fast_net.forward(task)
grads.append(g)
self.meta_update(task, grads)
def train(self, exp):
tr_loss, tr_acc, val_loss, val_acc = [], [], [], []
mtr_loss, mtr_acc, mval_loss, mval_acc = [], [], [], []
for it in range(self.num_updates):
# Evaluate on test tasks
mt_loss, mt_acc, mv_loss, mv_acc = self.test()
mtr_loss.append(mt_loss)
mtr_acc.append(mt_acc)
mval_loss.append(mv_loss)
mval_acc.append(mv_acc)
# Collect a meta batch update
grads = []
tloss, tacc, vloss, vacc = 0.0, 0.0, 0.0, 0.0
for i in range(self.meta_batch_size):
task = self.get_task('../data/{}'.format(self.dataset),
self.num_classes, self.num_inst)
self.fast_net.copy_weights(self.net)
metrics, g = self.fast_net.forward(task)
(trl, tra, vall, vala) = metrics
grads.append(g)
tloss += trl
tacc += tra
vloss += vall
vacc += vala
# Perform the meta update
print 'Meta update', it
self.meta_update(task, grads)
# Save a model snapshot every now and then
if it % 500 == 0:
torch.save(self.net.state_dict(),
'../output/{}/train_iter_{}.pth'.format(exp, it))
# Save stuff
tr_loss.append(tloss / self.meta_batch_size)
tr_acc.append(tacc / self.meta_batch_size)
val_loss.append(vloss / self.meta_batch_size)
val_acc.append(vacc / self.meta_batch_size)
np.save('../output/{}/tr_loss.npy'.format(exp), np.array(tr_loss))
np.save('../output/{}/tr_acc.npy'.format(exp), np.array(tr_acc))
np.save('../output/{}/val_loss.npy'.format(exp),
np.array(val_loss))
np.save('../output/{}/val_acc.npy'.format(exp), np.array(val_acc))
np.save('../output/{}/meta_tr_loss.npy'.format(exp),
np.array(mtr_loss))
np.save('../output/{}/meta_tr_acc.npy'.format(exp),
np.array(mtr_acc))
np.save('../output/{}/meta_val_loss.npy'.format(exp),
np.array(mval_loss))
np.save('../output/{}/meta_val_acc.npy'.format(exp),
np.array(mval_acc))
