def generate(agent_path,
out,
num=10000,
environ_path='output/RF_cls_ecfp6.pkg'):
""" Generating novel molecules with SMILES representation and
storing them into hard drive as a data frame.
Arguments:
agent_path (str): the neural states file paths for the RNN agent (generator).
out (str): file path for the generated molecules (and scores given by environment).
num (int, optional): the total No. of SMILES that need to be generated. (Default: 10000)
environ_path (str): the file path of the predictor for environment construction.
"""
batch_size = 500
df = pd.DataFrame()
voc = util.Voc("data/voc.txt")
agent = model.Generator(voc)
agent.load_state_dict(torch.load(agent_path))
for i in range(num // batch_size + 1):
if i == 0 and num % batch_size == 0: continue
batch = pd.DataFrame()
samples = agent.sample(batch_size if i != 0 else num % batch_size)
smiles, valids = util.check_smiles(samples, agent.voc)
if environ_path is not None:
# calculating the reward of each SMILES based on the environment (predictor).
environ = util.Environment(environ_path)
scores = environ(smiles)
scores[valids == 0] = 0
valids = scores
batch['SCORE'] = valids
batch['CANONICAL_SMILES'] = smiles
df = df.append(batch)
df.to_csv(out, sep='\t', index=None)
def fit(self, loader_train, out, loader_valid=None, epochs=100, lr=1e-3):
"""Training the RNN generative model, similar to the scikit-learn or Keras style.
In the end, the optimal value of parameters will also be persisted on the hard drive.
Arguments:
loader_train (DataLoader): Data loader for training set, it contains
Dataset with util.MolData; for each iteration, the output batch is
m X n LongTensor, m is the No. of samples, n is the maximum length
of sequences.
out (str): the file path for the model file (suffix with '.pkg')
valid_loader (DataLoader, optional): Data loader for validation set.
The data structure is as same as loader_train.
and log file (suffix with '.log').
epochs(int, optional): The maximum of training epochs (default: 100)
lr (float, optional): learning rate (default: 1e-4)
"""
optimizer = optim.Adam(self.parameters(), lr=lr)
log = open(out + '.log', 'w')
best_error = np.inf
for epoch in tqdm(range(epochs)):
for i, batch in tqdm(enumerate(loader_train), total=len(loader_train), desc='Epoch %d' % epoch):
optimizer.zero_grad()
loss_train = self.likelihood(batch.to(util.dev))
loss_train = -loss_train.mean()
loss_train.backward()
optimizer.step()
# Performance Evaluation
if i % 10 == 0 or loader_valid is not None:
# 1000 SMILES is sampled
seqs = self.sample(1000)
# ix = util.unique(seqs)
# seqs = seqs[ix]
# Checking the validation of each SMILES
smiles, valids = util.check_smiles(seqs, self.voc)
error = 1 - sum(valids) / len(seqs)
info = "Epoch: %d step: %d error_rate: %.3f loss_train: %.3f" % (epoch, i, error, loss_train.item())
# Saving the optimal parameter of the model with minimum loss value.
if loader_valid is not None:
# If the validation set is given, the loss function will be
# calculated on the validation set.
loss_valid, size = 0, 0
for j, batch in enumerate(loader_valid):
size += batch.size(0)
loss_valid += -self.likelihood(batch.to(util.dev)).sum()
print(size)
loss_valid = loss_valid / size / self.voc.max_len
if loss_valid.item() < best_error:
torch.save(self.state_dict(), out + '.pkg')
best_error = loss_valid.item()
info += ' loss_valid: %.3f' % loss_valid.item()
elif error < best_error:
# If the validation is not given, the loss function will be
# just based on the training set.
torch.save(self.state_dict(), out + '.pkg')
best_error = error
print(info, file=log)
for i, smile in enumerate(smiles):
print('%d\t%s' % (valids[i], smile), file=log)
log.close()
self.load_state_dict(torch.load(out + '.pkg'))
def main():
voc = util.Voc(init_from_file="data/voc_b.txt")
netR_path = 'output/rf_dis.pkg'
netG_path = 'output/net_p'
netD_path = 'output/net_d'
agent_path = 'output/net_gan_%d_%d_%dx%d' % (SIGMA * 10, BL * 10,
BATCH_SIZE, MC)
netR = util.Environment(netR_path)
agent = model.Generator(voc)
agent.load_state_dict(T.load(netG_path + '.pkg'))
df = pd.read_table('data/CHEMBL251.txt')
df = df[df['PCHEMBL_VALUE'] >= 6.5]
data = util.MolData(df, voc)
loader = DataLoader(data,
batch_size=BATCH_SIZE,
shuffle=True,
drop_last=True,
collate_fn=data.collate_fn)
netD = model.Discriminator(VOCAB_SIZE, EMBED_DIM, FILTER_SIZE, NUM_FILTER)
if not os.path.exists(netD_path + '.pkg'):
Train_dis_BCE(netD, agent, loader, epochs=100, out=netD_path)
netD.load_state_dict(T.load(netD_path + '.pkg'))
best_score = 0
log = open(agent_path + '.log', 'w')
for epoch in range(1000):
print('\n--------\nEPOCH %d\n--------' % (epoch + 1))
print('\nPolicy Gradient Training Generator : ')
Train_GAN(agent, netD, netR)
print('\nAdversarial Training Discriminator : ')
Train_dis_BCE(netD, agent, loader, epochs=1)
seqs = agent.sample(1000)
ix = util.unique(seqs)
smiles, valids = util.check_smiles(seqs[ix], agent.voc)
scores = netR(smiles)
scores[valids == False] = 0
unique = (scores >= 0.5).sum() / 1000
if best_score < unique:
T.save(agent.state_dict(), agent_path + '.pkg')
best_score = unique
print("Epoch+: %d average: %.4f valid: %.4f unique: %.4f" %
(epoch, scores.mean(), valids.mean(), unique),
file=log)
for i, smile in enumerate(smiles):
print('%f\t%s' % (scores[i], smile), file=log)
for param_group in agent.optim.param_groups:
param_group['lr'] *= (1 - 0.01)
log.close()
def Rollout_PG(agent, environ, explore=None):
"""Training generator under reinforcement learning framework,
The rewoard is given for each token in the SMILES, which is generated by
Monte Carlo Tree Search based on final reward given by the environment.
agent (model.Generator): the exploitation network for SMILES string generation
environ (util.Activity): the environment provide the final reward for each SMILES
explore (model.Generator): the exploration network for SMILES string generation,
it has the same architecture with the agent.
"""
agent.optim.zero_grad()
seqs = agent.sample(BATCH_SIZE, explore=explore, epsilon=Epsilon)
batch_size = seqs.size(0)
seq_len = seqs.size(1)
rewards = np.zeros((batch_size, seq_len))
smiles, valids = util.check_smiles(seqs, agent.voc)
preds = environ(smiles) - Baseline
preds[valids == False] = -Baseline
scores, hiddens = agent.likelihood(seqs)
# Monte Carlo Tree Search for step rewards generation
for _ in tqdm(range(MC)):
for i in range(0, seq_len):
if (seqs[:, i] != 0).any():
h = hiddens[:, :, i, :]
subseqs = agent.sample(batch_size,
inits=(seqs[:, i], h, i + 1, None))
subseqs = torch.cat([seqs[:, :i + 1], subseqs], dim=1)
subsmile, subvalid = util.check_smiles(subseqs, voc=agent.voc)
subpred = environ(subsmile) - Baseline
subpred[1 - subvalid] = -Baseline
else:
subpred = preds
rewards[:, i] += subpred
loss = agent.PGLoss(scores, seqs, torch.FloatTensor(rewards / MC))
loss.backward()
agent.optim.step()
return 0, valids.mean(), smiles, preds
def main():
global Epsilon
# Vocabulary containing all of the tokens for SMILES construction
voc = util.Voc("data/voc.txt")
# File path of predictor in the environment
environ_path = 'output/RF_cls_ecfp6.pkg'
# file path of hidden states in RNN for initialization
initial_path = 'output/net_p'
# file path of hidden states of optimal exploitation network
agent_path = 'output/net_e_%.2f_%.1f_%dx%d' % (Epsilon, Baseline,
BATCH_SIZE, MC)
# file path of hidden states of exploration network
explore_path = 'output/net_p'
# Environment (predictor)
environ = util.Environment(environ_path)
# Agent (generator, exploitation network)
agent = model.Generator(voc)
agent.load_state_dict(torch.load(initial_path + '.pkg'))
# exploration network
explore = model.Generator(voc)
explore.load_state_dict(torch.load(explore_path + '.pkg'))
best_score = 0
log = open(agent_path + '.log', 'w')
for epoch in range(1000):
print('\n--------\nEPOCH %d\n--------' % (epoch + 1))
print('\nForward Policy Gradient Training Generator : ')
Policy_gradient(agent, environ, explore=explore)
seqs = agent.sample(1000)
ix = util.unique(seqs)
smiles, valids = util.check_smiles(seqs[ix], agent.voc)
scores = environ(smiles)
scores[valids == False] = 0
unique = (scores >= 0.5).sum() / 1000
# The model with best percentage of unique desired SMILES will be persisted on the hard drive.
if best_score < unique:
torch.save(agent.state_dict(), agent_path + '.pkg')
best_score = unique
print("Epoch+: %d average: %.4f valid: %.4f unique: %.4f" %
(epoch, scores.mean(), valids.mean(), unique),
file=log)
for i, smile in enumerate(smiles):
print('%f\t%s' % (scores[i], smile), file=log)
# Learing rate exponential decay
for param_group in agent.optim.param_groups:
param_group['lr'] *= (1 - 0.01)
log.close()
def Train_GAN(netG, netD, netR, sigma=SIGMA):
seqs = []
for _ in range(MC):
seq = netG.sample(BATCH_SIZE)
seqs.append(seq)
seqs = T.cat(seqs, dim=0)
ix = util.unique(seqs)
seqs = seqs[ix]
smiles, valids = util.check_smiles(seqs, netG.voc)
preds = sigma * netR(smiles) + (1 - sigma) * netD(
util.Variable(seqs)).data.cpu().numpy()[:, 0]
preds[valids == False] = 0
preds -= BL
ds = TensorDataset(seqs, T.Tensor(preds.reshape(-1, 1)))
loader = DataLoader(ds, batch_size=BATCH_SIZE)
for seq, pred in loader:
score, _ = netG.likelihood(seq)
netG.optim.zero_grad()
loss = netG.PGLoss(score, seq, pred)
loss.backward()
netG.optim.step()
def Policy_gradient(agent, environ, explore=None):
"""Training generator under reinforcement learning framework,
The rewoard is only the final reward given by environment (predictor).
agent (model.Generator): the exploitation network for SMILES string generation
environ (util.Activity): the environment provide the final reward for each SMILES
explore (model.Generator): the exploration network for SMILES string generation,
it has the same architecture with the agent.
"""
seqs = []
# repeated sampling with MC times
for _ in range(MC):
seq = agent.sample(BATCH_SIZE, explore=explore, epsilon=Epsilon)
seqs.append(seq)
seqs = torch.cat(seqs, dim=0)
ix = util.unique(seqs)
seqs = seqs[ix]
smiles, valids = util.check_smiles(seqs, agent.voc)
# obtaining the reward
preds = environ(smiles)
preds[valids == False] = 0
preds -= Baseline
preds = torch.Tensor(preds.reshape(-1, 1)).to(util.dev)
ds = TensorDataset(seqs, preds)
loader = DataLoader(ds, batch_size=BATCH_SIZE)
# Training Loop
for seq, pred in loader:
score = agent.likelihood(seq)
agent.optim.zero_grad()
loss = agent.PGLoss(score, pred)
loss.backward()
agent.optim.step()
def fit(self, pair_loader, tgt_loader, epochs=100, out=None):
log = open(out + '.log', 'w')
best_valid = 0.
net = nn.DataParallel(self, device_ids=util.devices)
optimizer = torch.optim.Adam(self.parameters())
for epoch in range(epochs):
for i, (tgts, cmps) in enumerate(pair_loader):
tgts, cmps = tgts.to(util.dev), cmps.to(util.dev)
optimizer.zero_grad()
output = net(tgts, cmps)
loss = F.nll_loss(output.view(-1, self.voc_cmp.size),
cmps.view(-1))
loss.backward()
optimizer.step()
if i % 10 != 0 or i == 0: continue
ids, smiles, valids = [], [], []
for _ in range(4):
for ix, tgt in tgt_loader:
seqs = net(tgt.to(util.dev))
# ix = util.unique(seqs)
# seqs = seqs[ix]
smile, valid = util.check_smiles(seqs, self.voc_cmp)
smiles += smile
valids += valid
ids += ix.tolist()
valid = sum(valids) / len(valids)
print("Epoch: %d step: %d loss: %.3f valid: %.3f" %
(epoch, i, loss.item(), valid),
file=log)
for i, smile in enumerate(smiles):
print('%d\t%s' % (valids[i], smile), file=log)
if best_valid < valid:
torch.save(self.state_dict(), out + '.pkg')
best_valid = valid
log.close()