class ImitationLearning(object):
def __init__(
self,
args,
):
self.args = args
utils.seed(self.args.seed)
# args.env is a list when training on multiple environments
if getattr(args, 'multi_env', None):
self.env = [gym.make(item) for item in args.multi_env]
self.train_demos = []
for demos, episodes in zip(args.multi_demos, args.multi_episodes):
demos_path = utils.get_demos_path(demos,
None,
None,
valid=False)
logger.info('loading {} of {} demos'.format(episodes, demos))
train_demos = utils.load_demos(demos_path)
logger.info('loaded demos')
if episodes > len(train_demos):
raise ValueError(
"there are only {} train demos in {}".format(
len(train_demos), demos))
self.train_demos.extend(train_demos[:episodes])
logger.info('So far, {} demos loaded'.format(
len(self.train_demos)))
self.val_demos = []
for demos, episodes in zip(args.multi_demos, [args.val_episodes] *
len(args.multi_demos)):
demos_path_valid = utils.get_demos_path(demos,
None,
None,
valid=True)
logger.info('loading {} of {} valid demos'.format(
episodes, demos))
valid_demos = utils.load_demos(demos_path_valid)
logger.info('loaded demos')
if episodes > len(valid_demos):
logger.info(
'Using all the available {} demos to evaluate valid. accuracy'
.format(len(valid_demos)))
self.val_demos.extend(valid_demos[:episodes])
logger.info('So far, {} valid demos loaded'.format(
len(self.val_demos)))
logger.info('Loaded all demos')
observation_space = self.env[0].observation_space
action_space = self.env[0].action_space
else:
self.env = gym.make(self.args.env)
demos_path = utils.get_demos_path(args.demos,
args.env,
args.demos_origin,
valid=False)
demos_path_valid = utils.get_demos_path(args.demos,
args.env,
args.demos_origin,
valid=True)
print("else")
logger.info('loading demos')
self.train_demos = utils.load_demos(demos_path)
print(len(self.train_demos))
print(self.train_demos[0])
logger.info('loaded demos')
if args.episodes:
if args.episodes > len(self.train_demos):
raise ValueError("there are only {} train demos".format(
len(self.train_demos)))
self.train_demos = self.train_demos[:args.episodes]
self.val_demos = utils.load_demos(demos_path_valid)
if args.val_episodes > len(self.val_demos):
logger.info(
'Using all the available {} demos to evaluate valid. accuracy'
.format(len(self.val_demos)))
self.val_demos = self.val_demos[:self.args.val_episodes]
observation_space = self.env.observation_space
action_space = self.env.action_space
print("else")
print(args.model)
self.obss_preprocessor = utils.ObssPreprocessor(
args.model, observation_space,
getattr(self.args, 'pretrained_model', None))
# Define actor-critic model
self.acmodel = utils.load_model(args.model, raise_not_found=False)
if self.acmodel is None:
if getattr(self.args, 'pretrained_model', None):
self.acmodel = utils.load_model(args.pretrained_model,
raise_not_found=True)
else:
self.acmodel = ACModel(self.obss_preprocessor.obs_space,
action_space, args.image_dim,
args.memory_dim, args.instr_dim,
not self.args.no_instr,
self.args.instr_arch,
not self.args.no_mem, self.args.arch)
self.obss_preprocessor.vocab.save()
utils.save_model(self.acmodel, args.model)
self.acmodel.train()
if torch.cuda.is_available():
self.acmodel.cuda()
self.optimizer = torch.optim.Adam(self.acmodel.parameters(),
self.args.lr,
eps=self.args.optim_eps)
self.scheduler = torch.optim.lr_scheduler.StepLR(self.optimizer,
step_size=100,
gamma=0.9)
self.device = torch.device(
"cuda" if torch.cuda.is_available() else "cpu")
@staticmethod
def default_model_name(args):
if getattr(args, 'multi_env', None):
# It's better to specify one's own model name for this scenario
named_envs = '-'.join(args.multi_env)
else:
named_envs = args.env
# Define model name
suffix = datetime.datetime.now().strftime("%y-%m-%d-%H-%M-%S")
instr = args.instr_arch if args.instr_arch else "noinstr"
model_name_parts = {
'envs': named_envs,
'arch': args.arch,
'instr': instr,
'seed': args.seed,
'suffix': suffix
}
default_model_name = "{envs}_IL_{arch}_{instr}_seed{seed}_{suffix}".format(
**model_name_parts)
if getattr(args, 'pretrained_model', None):
default_model_name = args.pretrained_model + '_pretrained_' + default_model_name
return default_model_name
def starting_indexes(self, num_frames):
if num_frames % self.args.recurrence == 0:
return np.arange(0, num_frames, self.args.recurrence)
else:
return np.arange(0, num_frames, self.args.recurrence)[:-1]
def run_epoch_recurrence(self, demos, is_training=False):
indices = list(range(len(demos)))
if is_training:
np.random.shuffle(indices)
batch_size = min(self.args.batch_size, len(demos))
offset = 0
if not is_training:
self.acmodel.eval()
# Log dictionary
log = {"entropy": [], "policy_loss": [], "accuracy": []}
start_time = time.time()
frames = 0
for batch_index in range(len(indices) // batch_size):
logger.info("batch {}, FPS so far {}".format(
batch_index,
frames / (time.time() - start_time) if frames else 0))
batch = [demos[i] for i in indices[offset:offset + batch_size]]
frames += sum([len(demo[3]) for demo in batch])
_log = self.run_epoch_recurrence_one_batch(batch,
is_training=is_training)
log["entropy"].append(_log["entropy"])
log["policy_loss"].append(_log["policy_loss"])
log["accuracy"].append(_log["accuracy"])
offset += batch_size
if not is_training:
self.acmodel.train()
return log
def run_epoch_recurrence_one_batch(self, batch, is_training=False):
batch = utils.demos.transform_demos(batch)
batch.sort(key=len, reverse=True)
# Constructing flat batch and indices pointing to start of each demonstration
flat_batch = []
inds = [0]
for demo in batch:
flat_batch += demo
inds.append(inds[-1] + len(demo))
flat_batch = np.array(flat_batch)
inds = inds[:-1]
num_frames = len(flat_batch)
mask = np.ones([len(flat_batch)], dtype=np.float64)
mask[inds] = 0
mask = torch.tensor(mask, device=self.device,
dtype=torch.float).unsqueeze(1)
# Observations, true action, values and done for each of the stored demostration
obss, action_true, done = flat_batch[:,
0], flat_batch[:,
1], flat_batch[:,
2]
action_true = torch.tensor([action for action in action_true],
device=self.device,
dtype=torch.long)
# Memory to be stored
memories = torch.zeros([len(flat_batch), self.acmodel.memory_size],
device=self.device)
episode_ids = np.zeros(len(flat_batch))
memory = torch.zeros([len(batch), self.acmodel.memory_size],
device=self.device)
preprocessed_first_obs = self.obss_preprocessor(obss[inds],
device=self.device)
instr_embedding = self.acmodel._get_instr_embedding(
preprocessed_first_obs.instr)
# Loop terminates when every observation in the flat_batch has been handled
while True:
# taking observations and done located at inds
obs = obss[inds]
done_step = done[inds]
preprocessed_obs = self.obss_preprocessor(obs, device=self.device)
with torch.no_grad():
# taking the memory till len(inds), as demos beyond that have already finished
new_memory = self.acmodel(
preprocessed_obs, memory[:len(inds), :],
instr_embedding[:len(inds)])['memory']
memories[inds, :] = memory[:len(inds), :]
memory[:len(inds), :] = new_memory
episode_ids[inds] = range(len(inds))
# Updating inds, by removing those indices corresponding to which the demonstrations have finished
inds = inds[:len(inds) - sum(done_step)]
if len(inds) == 0:
break
# Incrementing the remaining indices
inds = [index + 1 for index in inds]
# Here, actual backprop upto args.recurrence happens
final_loss = 0
final_entropy, final_policy_loss, final_value_loss = 0, 0, 0
indexes = self.starting_indexes(num_frames)
memory = memories[indexes]
accuracy = 0
total_frames = len(indexes) * self.args.recurrence
for _ in range(self.args.recurrence):
obs = obss[indexes]
preprocessed_obs = self.obss_preprocessor(obs, device=self.device)
action_step = action_true[indexes]
mask_step = mask[indexes]
model_results = self.acmodel(preprocessed_obs, memory * mask_step,
instr_embedding[episode_ids[indexes]])
dist = model_results['dist']
memory = model_results['memory']
entropy = dist.entropy().mean()
policy_loss = -dist.log_prob(action_step).mean()
loss = policy_loss - self.args.entropy_coef * entropy
action_pred = dist.probs.max(1, keepdim=True)[1]
accuracy += float(
(action_pred == action_step.unsqueeze(1)).sum()) / total_frames
final_loss += loss
final_entropy += entropy
final_policy_loss += policy_loss
indexes += 1
final_loss /= self.args.recurrence
if is_training:
self.optimizer.zero_grad()
final_loss.backward()
self.optimizer.step()
log = {}
log["entropy"] = float(final_entropy / self.args.recurrence)
log["policy_loss"] = float(final_policy_loss / self.args.recurrence)
log["accuracy"] = float(accuracy)
return log
def validate(self, episodes, verbose=True):
# Seed needs to be reset for each validation, to ensure consistency
utils.seed(self.args.val_seed)
if verbose:
logger.info("Validating the model")
if getattr(self.args, 'multi_env', None):
agent = utils.load_agent(self.env[0],
model_name=self.args.model,
argmax=True)
else:
agent = utils.load_agent(self.env,
model_name=self.args.model,
argmax=True)
# Setting the agent model to the current model
agent.model = self.acmodel
agent.model.eval()
logs = []
for env_name in ([self.args.env]
if not getattr(self.args, 'multi_env', None) else
self.args.multi_env):
logs += [
batch_evaluate(agent, env_name, self.args.val_seed, episodes)
]
agent.model.train()
return logs
def collect_returns(self):
logs = self.validate(episodes=self.args.eval_episodes, verbose=False)
mean_return = {
tid: np.mean(log["return_per_episode"])
for tid, log in enumerate(logs)
}
return mean_return
def train(self,
train_demos,
writer,
csv_writer,
status_path,
header,
reset_status=False):
# Load the status
def initial_status():
return {'i': 0, 'num_frames': 0, 'patience': 0}
status = initial_status()
if os.path.exists(status_path) and not reset_status:
with open(status_path, 'r') as src:
status = json.load(src)
elif not os.path.exists(os.path.dirname(status_path)):
# Ensure that the status directory exists
os.makedirs(os.path.dirname(status_path))
# If the batch size is larger than the number of demos, we need to lower the batch size
if self.args.batch_size > len(train_demos):
self.args.batch_size = len(train_demos)
logger.info(
"Batch size too high. Setting it to the number of train demos ({})"
.format(len(train_demos)))
# Model saved initially to avoid "Model not found Exception" during first validation step
utils.save_model(self.acmodel, self.args.model)
# best mean return to keep track of performance on validation set
best_success_rate, patience, i = 0, 0, 0
total_start_time = time.time()
while status['i'] < getattr(self.args, 'epochs', int(1e9)):
if 'patience' not in status: # if for some reason you're finetuining with IL an RL pretrained agent
status['patience'] = 0
# Do not learn if using a pre-trained model that already lost patience
if status['patience'] > self.args.patience:
break
if status['num_frames'] > self.args.frames:
break
status['i'] += 1
i = status['i']
update_start_time = time.time()
# Learning rate scheduler
self.scheduler.step()
log = self.run_epoch_recurrence(train_demos, is_training=True)
total_len = sum([len(item[3]) for item in train_demos])
status['num_frames'] += total_len
update_end_time = time.time()
# Print logs
if status['i'] % self.args.log_interval == 0:
total_ellapsed_time = int(time.time() - total_start_time)
fps = total_len / (update_end_time - update_start_time)
duration = datetime.timedelta(seconds=total_ellapsed_time)
for key in log:
log[key] = np.mean(log[key])
train_data = [
status['i'], status['num_frames'], fps,
total_ellapsed_time, log["entropy"], log["policy_loss"],
log["accuracy"]
]
logger.info(
"U {} | F {:06} | FPS {:04.0f} | D {} | H {:.3f} | pL {: .3f} | A {: .3f}"
.format(*train_data))
# Log the gathered data only when we don't evaluate the validation metrics. It will be logged anyways
# afterwards when status['i'] % self.args.val_interval == 0
if status['i'] % self.args.val_interval != 0:
# instantiate a validation_log with empty strings when no validation is done
validation_data = [''] * len(
[key for key in header if 'valid' in key])
assert len(header) == len(train_data + validation_data)
if self.args.tb:
for key, value in zip(header, train_data):
writer.add_scalar(key, float(value),
status['num_frames'])
csv_writer.writerow(train_data + validation_data)
if status['i'] % self.args.val_interval == 0:
valid_log = self.validate(self.args.val_episodes)
mean_return = [
np.mean(log['return_per_episode']) for log in valid_log
]
success_rate = [
np.mean(
[1 if r > 0 else 0 for r in log['return_per_episode']])
for log in valid_log
]
val_log = self.run_epoch_recurrence(self.val_demos)
validation_accuracy = np.mean(val_log["accuracy"])
if status['i'] % self.args.log_interval == 0:
validation_data = [validation_accuracy
] + mean_return + success_rate
logger.info(("Validation: A {: .3f} " +
("| R {: .3f} " * len(mean_return) +
"| S {: .3f} " * len(success_rate))).format(
*validation_data))
assert len(header) == len(train_data + validation_data)
if self.args.tb:
for key, value in zip(header,
train_data + validation_data):
writer.add_scalar(key, float(value),
status['num_frames'])
csv_writer.writerow(train_data + validation_data)
# In case of a multi-env, the update condition would be "better mean success rate" !
if np.mean(success_rate) > best_success_rate:
best_success_rate = np.mean(success_rate)
status['patience'] = 0
with open(status_path, 'w') as dst:
json.dump(status, dst)
# Saving the model
logger.info("Saving best model")
if torch.cuda.is_available():
self.acmodel.cpu()
utils.save_model(self.acmodel, self.args.model + "_best")
self.obss_preprocessor.vocab.save(
utils.get_vocab_path(self.args.model + "_best"))
if torch.cuda.is_available():
self.acmodel.cuda()
else:
status['patience'] += 1
logger.info(
"Losing patience, new value={}, limit={}".format(
status['patience'], self.args.patience))
if torch.cuda.is_available():
self.acmodel.cpu()
utils.save_model(self.acmodel, self.args.model)
if torch.cuda.is_available():
self.acmodel.cuda()
with open(status_path, 'w') as dst:
json.dump(status, dst)
class MetaLearner(nn.Module):
"""
Meta Learner
"""
def __init__(self, args):
"""
:param args:
"""
super(MetaLearner, self).__init__()
self.update_lr = args.update_lr
self.meta_lr = args.meta_lr
self.task_num = args.task_num
self.args = args
utils.seed(self.args.seed)
self.env = gym.make(self.args.env)
demos_path = utils.get_demos_path(args.demos,
args.env,
args.demos_origin,
valid=False)
demos_path_valid = utils.get_demos_path(args.demos,
args.env,
args.demos_origin,
valid=True)
logger.info('loading demos')
self.train_demos = utils.load_demos(demos_path)
logger.info('loaded demos')
# if args.episodes:
# if args.episodes > len(self.train_demos):
# raise ValueError("there are only {} train demos".format(len(self.train_demos)))
# self.train_demos = self.train_demos[:args.episodes]
self.val_demos = utils.load_demos(demos_path_valid)
# if args.val_episodes > len(self.val_demos):
# logger.info('Using all the available {} demos to evaluate valid. accuracy'.format(len(self.val_demos)))
self.val_demos = self.val_demos[:self.args.val_episodes]
observation_space = self.env.observation_space
action_space = self.env.action_space
print(args.model)
self.obss_preprocessor = utils.ObssPreprocessor(
args.model, observation_space,
getattr(self.args, 'pretrained_model', None))
# Define actor-critic model
# self.net = utils.load_model(args.model, raise_not_found=False)
# if self.net is None:
# if getattr(self.args, 'pretrained_model', None):
# self.net = utils.load_model(args.pretrained_model, raise_not_found=True)
# else:
self.net = ACModel(self.obss_preprocessor.obs_space, action_space,
args.image_dim, args.memory_dim, args.instr_dim,
not self.args.no_instr, self.args.instr_arch,
not self.args.no_mem, self.args.arch)
self.obss_preprocessor.vocab.save()
# utils.save_model(self.net, args.model)
self.fast_net = copy.deepcopy(self.net)
self.net.train()
self.fast_net.train()
if torch.cuda.is_available():
self.net.cuda()
self.fast_net.cuda()
self.optimizer = torch.optim.SGD(self.fast_net.parameters(),
lr=self.args.update_lr)
# self.scheduler = torch.optim.lr_scheduler.StepLR(self.optimizer, step_size=100, gamma=0.9)
self.device = torch.device(
"cuda" if torch.cuda.is_available() else "cpu")
self.meta_optim = optim.Adam(self.net.parameters(), lr=self.meta_lr)
def clip_grad_by_norm_(self, grad, max_norm):
"""
in-place gradient clipping.
:param grad: list of gradients
:param max_norm: maximum norm allowable
:return:
"""
total_norm = 0
counter = 0
for g in grad:
param_norm = g.data.norm(2)
total_norm += param_norm.item()**2
counter += 1
total_norm = total_norm**(1. / 2)
clip_coef = max_norm / (total_norm + 1e-6)
if clip_coef < 1:
for g in grad:
g.data.mul_(clip_coef)
return total_norm / counter
def starting_indexes(self, num_frames):
if num_frames % self.args.recurrence == 0:
return np.arange(0, num_frames, self.args.recurrence)
else:
return np.arange(0, num_frames, self.args.recurrence)[:-1]
def forward_batch(self, batch, task, net='fast', is_training=True):
if net == 'fast':
acmodel = self.fast_net
else:
acmodel = self.net
batch = utils.demos.induce_grammar(batch, task)
batch = utils.demos.transform_demos(batch)
batch.sort(key=len, reverse=True)
# Constructing flat batch and indices pointing to start of each demonstration
flat_batch = []
inds = [0]
for demo in batch:
flat_batch += demo
inds.append(inds[-1] + len(demo))
flat_batch = np.array(flat_batch)
inds = inds[:-1]
num_frames = len(flat_batch)
mask = np.ones([len(flat_batch)], dtype=np.float64)
mask[inds] = 0
mask = torch.tensor(mask, device=self.device,
dtype=torch.float).unsqueeze(1)
# Observations, true action, values and done for each of the stored demostration
obss, action_true, done = flat_batch[:,
0], flat_batch[:,
1], flat_batch[:,
2]
action_true = torch.tensor([action for action in action_true],
device=self.device,
dtype=torch.long)
# Memory to be stored
memories = torch.zeros([len(flat_batch), acmodel.memory_size],
device=self.device)
episode_ids = np.zeros(len(flat_batch))
memory = torch.zeros([len(batch), acmodel.memory_size],
device=self.device)
preprocessed_first_obs = self.obss_preprocessor(obss[inds],
device=self.device)
instr_embedding = acmodel._get_instr_embedding(
preprocessed_first_obs.instr)
# Loop terminates when every observation in the flat_batch has been handled
while True:
# taking observations and done located at inds
obs = obss[inds]
done_step = done[inds]
preprocessed_obs = self.obss_preprocessor(obs, device=self.device)
with torch.no_grad():
# taking the memory till len(inds), as demos beyond that have already finished
new_memory = acmodel(preprocessed_obs, memory[:len(inds), :],
instr_embedding[:len(inds)])['memory']
memories[inds, :] = memory[:len(inds), :]
memory[:len(inds), :] = new_memory
episode_ids[inds] = range(len(inds))
# Updating inds, by removing those indices corresponding to which the demonstrations have finished
inds = inds[:len(inds) - sum(done_step)]
if len(inds) == 0:
break
# Incrementing the remaining indices
inds = [index + 1 for index in inds]
# Here, actual backprop upto args.recurrence happens
final_loss = 0
final_entropy, final_policy_loss, final_value_loss = 0, 0, 0
indexes = self.starting_indexes(num_frames)
memory = memories[indexes]
accuracy = 0
total_frames = len(indexes) * self.args.recurrence
for _ in range(self.args.recurrence):
obs = obss[indexes]
preprocessed_obs = self.obss_preprocessor(obs, device=self.device)
action_step = action_true[indexes]
mask_step = mask[indexes]
model_results = acmodel(preprocessed_obs, memory * mask_step,
instr_embedding[episode_ids[indexes]])
dist = model_results['dist']
memory = model_results['memory']
entropy = dist.entropy().mean()
policy_loss = -dist.log_prob(action_step).mean()
loss = policy_loss - self.args.entropy_coef * entropy
action_pred = dist.probs.max(1, keepdim=True)[1]
accuracy += float(
(action_pred == action_step.unsqueeze(1)).sum()) / total_frames
final_loss += loss
final_entropy += entropy
final_policy_loss += policy_loss
indexes += 1
final_loss /= self.args.recurrence
# if is_training:
# self.optimizer.zero_grad()
# final_loss.backward()
# self.optimizer.step()
log = {}
log["entropy"] = float(final_entropy / self.args.recurrence)
log["policy_loss"] = float(final_policy_loss / self.args.recurrence)
log["accuracy"] = float(accuracy)
return final_loss, log
# def forward(self, x_spt, y_spt, x_qry, y_qry):
def forward(self, demo):
task_num = self.args.task_num
losses = [] # losses_q[i], i is tasks idx
logs = []
grads = []
self.optimizer.zero_grad()
for i in range(task_num):
# copy initializing net
self.fast_net = copy.deepcopy(self.net)
for p in self.fast_net.parameters():
p.retain_grad()
self.fast_net.zero_grad()
# optimize fast net for k isntances of task i
loss_task, log = self.forward_batch(demo, i, 'fast')
# grad = torch.autograd.grad(loss_task, self.fast_net.parameters(),allow_unused = True)
loss_task.backward()
grad = [x.grad for x in self.fast_net.parameters()]
# print (grad)
grads.append(grad)
# self.optimizer.step()
# loss_task, log = self.forward_batch(demo, i, 'fast')
# losses.append(loss_task)
logs.append(log)
self.meta_update(demo, grads)
# end of all tasks
# sum over all losses on query set across all tasks
# loss_q = sum(losses) / task_num
# # optimize theta parameters
# self.meta_optim.zero_grad()
# grad = torch.autograd.grad(loss_q, self.net.parameters(), allow_unused=True)
# print (grad)
# # loss_q.backward()
# for g,p in zip(grad,self.net.parameters()):
# p.grad = g
# # print('meta update')
# # for p in self.net.parameters()[:5]:
# # (torch.norm(p).item())
# self.meta_optim.step()
return logs
def meta_update(self, demo, grads):
print('\n Meta update \n')
# We use a dummy forward / backward pass to get the correct grads into self.net
loss, _ = self.forward_batch(demo, 0, 'net')
gradients = []
for p in self.net.parameters():
gradients.append(torch.zeros(np.array(p.data).shape).cuda())
# Unpack the list of grad dicts
for i in range(len(grads[0])):
for grad in grads:
if grad[i] is not None:
gradients[i] = gradients[i] + grad[i][0]
# gradients = [sum(grad[i][0] for grad in grads) for i in range(len(grads[0]))]
# 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 i, p in enumerate(self.net.parameters()):
def get_closure():
it = i
def replace_grad(grad):
ng = Variable(
torch.from_numpy(
np.array(gradients[it], dtype=np.float32))).cuda()
return ng
return replace_grad
try:
hooks.append(p.register_hook(get_closure()))
except:
print(p)
get_closure()
# Compute grads for current step, replace with summed gradients as defined by hook
self.meta_optim.zero_grad()
loss.backward()
# Update the net parameters with the accumulated gradient according to optimizer
self.meta_optim.step()
# Remove the hooks before next training phase
for h in hooks:
h.remove()
def validate(self, demo):
val_task_num = self.args.task_num
losses = [] # losses_q[i], i is tasks idx
logs = []
val_logs = []
for i in range(19):
self.fast_net = copy.deepcopy(self.net)
self.fast_net.zero_grad()
# optimize fast net for k isntances of task i
for k in range(5):
loss_task, log = self.forward_batch(demo[32 * k:32 * k + 32],
119 - i, 'fast')
self.optimizer.zero_grad()
loss_task.backward()
self.optimizer.step()
# loss_task, log = self.forward_batch(demo, i, 'fast')
# losses.append(loss_task)
logs.append(log)
loss_task, log = self.forward_batch(demo[32 * k:32 * k + 32],
119 - i, 'fast')
val_logs.append(log)
return val_logs