class Attention(object):
def __init__(self, channel=None):
self.rng_numpy, self.rng_theano = get_two_rngs()
self.layers = Layers()
self.predict = Predict()
self.channel = channel
def load_params(self, path, params):
# load params from disk
pp = np.load(path)
for kk, vv in params.iteritems():
if kk not in pp:
raise Warning('%s is not in the archive'%kk)
params[kk] = pp[kk]
return params
def init_params(self, options):
# all parameters
params = OrderedDict()
# embedding
params['Wemb'] = norm_weight(options['n_words'], options['dim_word'])
ctx_dim = options['ctx_dim']
# init_state, init_cell
params = self.layers.get_layer('ff')[0](params, nin=ctx_dim, nout=options['mu_dim'],
prefix='ff_state')
params = self.layers.get_layer('ff')[0](params, nin=ctx_dim, nout=options['mu_dim'],
prefix='ff_memory')
# decoder: LSTM
params = self.layers.get_layer('lstm')[0](params, nin=options['dim_word'],
dim=options['tu_dim'], prefix='tu_lstm')
params = self.layers.get_layer('attend')[0](params, nin=options['tu_dim'],
dimctx=ctx_dim, prefix='attend')
params = self.layers.get_layer('lstm_concat')[0](options, params, nin=options['tu_dim'],
dim=options['mu_dim'], dimctx=ctx_dim,
prefix='mu_lstm')
# readout
params = self.layers.get_layer('ff')[0](params, nin=options['mu_dim'], nout=options['dim_word'],
prefix='ff_logit_lstm')
if options['ctx2out']:
params = self.layers.get_layer('ff')[0](params, nin=ctx_dim, nout=options['dim_word'],
prefix='ff_logit_ctx')
params = self.layers.get_layer('ff')[0](params, nin=options['dim_word'], nout=options['n_words'],
prefix='ff_logit')
return params
def build_model(self, tparams, options):
trng = RandomStreams(1234)
use_noise = theano.shared(np.float32(0.))
# description string: #words x #samples
x = tensor.matrix('x', dtype='int64')
mask = tensor.matrix('mask', dtype='float32')
# context: #samples x #annotations x dim
ctx = tensor.tensor3('ctx', dtype='float32')
mask_ctx = tensor.matrix('mask_ctx', dtype='float32')
n_timesteps = x.shape[0]
n_samples = x.shape[1]
# index into the word embedding matrix, shift it forward in time
emb = tparams['Wemb'][x.flatten()].reshape(
[n_timesteps, n_samples, options['dim_word']])
emb_shifted = tensor.zeros_like(emb)
emb_shifted = tensor.set_subtensor(emb_shifted[1:], emb[:-1])
emb = emb_shifted
ctx_ = ctx
counts = mask_ctx.sum(-1).dimshuffle(0,'x')
ctx_mean = ctx_.sum(1)/counts
# initial state/cell
init_state = self.layers.get_layer('ff')[1](tparams, ctx_mean,
activ='tanh', prefix='ff_state')
init_memory = self.layers.get_layer('ff')[1](tparams, ctx_mean,
activ='tanh', prefix='ff_memory')
# decoder
tu_lstm = self.layers.get_layer('lstm')[1](tparams, emb, mask=mask, prefix='tu_lstm')
attend = self.layers.get_layer('attend')[1](tparams, tu_lstm[0], ctx_)
mu_lstm = self.layers.get_layer('lstm_concat')[1](options, tparams, tu_lstm[0],
mask=mask, ctxs=attend[1],
one_step=False,
init_state=init_state,
init_memory=init_memory,
trng=trng,
use_noise=use_noise,
prefix='mu_lstm')
proj_h = mu_lstm[0]
betas = mu_lstm[2]
ctxs = mu_lstm[3]
alphas = attend[0]
if options['use_dropout']:
proj_h = self.layers.dropout_layer(proj_h, use_noise, trng)
# compute word probabilities
logit = self.layers.get_layer('ff')[1](tparams, proj_h, activ='linear',
prefix='ff_logit_lstm')
if options['prev2out']:
logit += emb
if options['ctx2out']:
logit += self.layers.get_layer('ff')[1](tparams, ctxs, activ='linear',
prefix='ff_logit_ctx')
logit = tanh(logit)
if options['use_dropout']:
logit = self.layers.dropout_layer(logit, use_noise, trng)
# (t,m,n_words)
logit = self.layers.get_layer('ff')[1](tparams, logit,
activ='linear', prefix='ff_logit')
logit_shp = logit.shape
# (t*m, n_words)
probs = tensor.nnet.softmax(logit.reshape([logit_shp[0]*logit_shp[1],
logit_shp[2]]))
# cost
x_flat = x.flatten() # (t*m,)
cost = -tensor.log(probs[T.arange(x_flat.shape[0]), x_flat] + 1e-8)
cost = cost.reshape([x.shape[0], x.shape[1]])
cost = (cost * mask).sum(0)
extra = [probs, alphas, betas]
test = [attend[1]]
return trng, use_noise, x, mask, ctx, mask_ctx, alphas, cost, extra, test
def pred_probs(self, whichset, f_log_probs, verbose=True):
probs = []
n_done = 0
NLL = []
L = []
if whichset == 'train':
tags = self.engine.train
iterator = self.engine.kf_train
elif whichset == 'valid':
tags = self.engine.valid
iterator = self.engine.kf_valid
elif whichset == 'test':
tags = self.engine.test
iterator = self.engine.kf_test
else:
raise NotImplementedError()
n_samples = np.sum([len(index) for index in iterator])
for index in iterator:
tag = [tags[i] for i in index]
x, mask, ctx, ctx_mask,vid_names = data_engine.prepare_data(
self.engine, tag)
pred_probs = f_log_probs(x, mask, ctx, ctx_mask)
L.append(mask.sum(0).tolist())
NLL.append((-1 * pred_probs).tolist())
probs.append(pred_probs.tolist())
n_done += len(tag)
if verbose:
sys.stdout.write('\rComputing LL on %d/%d examples'%(
n_done, n_samples))
sys.stdout.flush()
print
probs = flatten_list_of_list(probs)
NLL = flatten_list_of_list(NLL)
L = flatten_list_of_list(L)
perp = 2**(np.sum(NLL) / np.sum(L) / np.log(2))
return -1 * np.mean(probs), perp
def train(self,
random_seed=1234,
reload_=False,
verbose=True,
debug=True,
save_model_dir='',
from_dir=None,
# dataset
dataset='youtube2text',
video_feature='googlenet',
K=10,
OutOf=240,
# network
dim_word=256, # word vector dimensionality
ctx_dim=-1, # context vector dimensionality, auto set
tu_dim=512,
mu_dim=1024,
vu_dim=1024,
n_layers_out=1,
n_layers_init=1,
prev2out=False,
ctx2out=False,
selector=False,
n_words=100000,
maxlen=100, # maximum length of the description
use_dropout=False,
isGlobal=False,
# training
patience=10,
max_epochs=5000,
decay_c=0.,
alpha_c=0.,
alpha_entropy_r=0.,
lrate=0.01,
optimizer='adadelta',
clip_c=2.,
# minibatch
batch_size = 64,
valid_batch_size = 64,
dispFreq=100,
validFreq=10,
saveFreq=10, # save the parameters after every saveFreq updates
sampleFreq=10, # generate some samples after every sampleFreq updates
# metric
metric='blue'
):
self.rng_numpy, self.rng_theano = get_two_rngs()
model_options = locals().copy()
if 'self' in model_options:
del model_options['self']
model_options = validate_options(model_options)
with open('%smodel_options.pkl'%save_model_dir, 'wb') as f:
pkl.dump(model_options, f)
print 'Loading data'
self.engine = data_engine.Movie2Caption('attention', dataset,
video_feature,
batch_size, valid_batch_size,
maxlen, n_words,
K, OutOf)
model_options['ctx_dim'] = self.engine.ctx_dim
print 'init params'
t0 = time.time()
params = self.init_params(model_options)
# reloading
if reload_:
model_saved = from_dir+'/model_best_so_far.npz'
assert os.path.isfile(model_saved)
print "Reloading model params..."
params = load_params(model_saved, params)
tparams = init_tparams(params)
if verbose:
print tparams.keys
trng, use_noise, x, mask, ctx, mask_ctx, alphas, cost, extra, test = \
self.build_model(tparams, model_options)
if debug:
print 'buliding test'
test_fun = theano.function([x, mask, ctx, mask_ctx],
test,
name='f_test',
on_unused_input='ignore')
print 'buliding sampler'
f_init, f_next = self.predict.build_sampler(self.layers, tparams, model_options, use_noise, trng)
# before any regularizer
print 'building f_log_probs'
f_log_probs = theano.function([x, mask, ctx, mask_ctx], -cost,
profile=False, on_unused_input='ignore')
cost = cost.mean()
if decay_c > 0.:
decay_c = theano.shared(np.float32(decay_c), name='decay_c')
weight_decay = 0.
for kk, vv in tparams.iteritems():
weight_decay += (vv ** 2).sum()
weight_decay *= decay_c
cost += weight_decay
if alpha_c > 0.:
alpha_c = theano.shared(np.float32(alpha_c), name='alpha_c')
alpha_reg = alpha_c * ((1.-alphas.sum(0))**2).sum(0).mean()
cost += alpha_reg
if alpha_entropy_r > 0:
alpha_entropy_r = theano.shared(np.float32(alpha_entropy_r),
name='alpha_entropy_r')
alpha_reg_2 = alpha_entropy_r * (-tensor.sum(alphas *
tensor.log(alphas+1e-8),axis=-1)).sum(0).mean()
cost += alpha_reg_2
else:
alpha_reg_2 = tensor.zeros_like(cost)
print 'building f_alpha'
f_alpha = theano.function([x, mask, ctx, mask_ctx],
[alphas, alpha_reg_2],
name='f_alpha',
on_unused_input='ignore')
print 'compute grad'
grads = tensor.grad(cost, wrt=itemlist(tparams))
if clip_c > 0.:
g2 = 0.
for g in grads:
g2 += (g**2).sum()
new_grads = []
for g in grads:
new_grads.append(tensor.switch(g2 > (clip_c**2),
g / tensor.sqrt(g2) * clip_c,
g))
grads = new_grads
lr = tensor.scalar(name='lr')
print 'build train fns'
f_grad_shared, f_update = eval(optimizer)(lr, tparams, grads,
[x, mask, ctx, mask_ctx], cost,
extra + grads)
print 'compilation took %.4f sec'%(time.time()-t0)
print 'Optimization'
history_errs = []
# reload history
if reload_:
print 'loading history error...'
history_errs = np.load(
from_dir+'model_best_so_far.npz')['history_errs'].tolist()
bad_counter = 0
processes = None
queue = None
rqueue = None
shared_params = None
uidx = 0
uidx_best_blue = 0
uidx_best_valid_err = 0
estop = False
best_p = unzip(tparams)
best_blue_valid = 0
best_valid_err = 999
alphas_ratio = []
for eidx in xrange(max_epochs):
n_samples = 0
train_costs = []
grads_record = []
print 'Epoch ', eidx
for idx in self.engine.kf_train:
tags = [self.engine.train[index] for index in idx]
n_samples += len(tags)
uidx += 1
use_noise.set_value(1.)
pd_start = time.time()
x, mask, ctx, ctx_mask,vid_names = data_engine.prepare_data(
self.engine, tags)
if debug:
datas = test_fun(x, mask, ctx, ctx_mask)
for item in datas:
print item[0].shape
pd_duration = time.time() - pd_start
if x is None:
print 'Minibatch with zero sample under length ', maxlen
continue
ud_start = time.time()
rvals = f_grad_shared(x, mask, ctx, ctx_mask)
cost = rvals[0]
probs = rvals[1]
alphas = rvals[2]
betas = rvals[3]
grads = rvals[4:]
grads, NaN_keys = grad_nan_report(grads, tparams)
if len(grads_record) >= 5:
del grads_record[0]
grads_record.append(grads)
if NaN_keys != []:
print 'grads contain NaN'
import pdb; pdb.set_trace()
if np.isnan(cost) or np.isinf(cost):
print 'NaN detected in cost'
import pdb; pdb.set_trace()
# update params
f_update(lrate)
ud_duration = time.time() - ud_start
if eidx == 0:
train_error = cost
else:
train_error = train_error * 0.95 + cost * 0.05
train_costs.append(cost)
if np.mod(uidx, dispFreq) == 0:
print 'Epoch ', eidx, ', Update ', uidx, \
', Train cost mean so far', train_error, \
', betas mean', np.round(betas.mean(), 3), \
', fetching data time spent (sec)', np.round(pd_duration, 3), \
', update time spent (sec)', np.round(ud_duration, 3)
alphas,reg = f_alpha(x,mask,ctx,ctx_mask)
print 'alpha ratio %.3f, reg %.3f' % (
alphas.min(-1).mean() / (alphas.max(-1)).mean(), reg)
if np.mod(uidx, saveFreq) == 0:
pass
if np.mod(uidx, sampleFreq) == 0:
use_noise.set_value(0.)
print '------------- sampling from train ----------'
self.predict.sample_execute(self.engine, model_options, tparams,
f_init, f_next, x, ctx, ctx_mask, trng,vid_names)
print '------------- sampling from valid ----------'
idx = self.engine.kf_valid[np.random.randint(1, len(self.engine.kf_valid) - 1)]
tags = [self.engine.valid[index] for index in idx]
x_s, mask_s, ctx_s, mask_ctx_s,vid_names = data_engine.prepare_data(self.engine, tags)
self.predict.sample_execute(self.engine, model_options, tparams,
f_init, f_next, x_s, ctx_s, mask_ctx_s, trng, vid_names)
# end of sample
if validFreq != -1 and np.mod(uidx, validFreq) == 0:
t0_valid = time.time()
alphas,_ = f_alpha(x, mask, ctx, ctx_mask)
ratio = alphas.min(-1).mean()/(alphas.max(-1)).mean()
alphas_ratio.append(ratio)
np.savetxt(save_model_dir+'alpha_ratio.txt',alphas_ratio)
current_params = unzip(tparams)
np.savez(save_model_dir+'model_current.npz',
history_errs=history_errs, **current_params)
use_noise.set_value(0.)
train_err = -1
train_perp = -1
valid_err = -1
valid_perp = -1
test_err = -1
test_perp = -1
if not debug:
# first compute train cost
if 0:
print 'computing cost on trainset'
train_err, train_perp = self.pred_probs(
'train', f_log_probs,
verbose=model_options['verbose'])
else:
train_err = 0.
train_perp = 0.
if 1:
print 'validating...'
valid_err, valid_perp = self.pred_probs(
'valid', f_log_probs,
verbose=model_options['verbose'],
)
else:
valid_err = 0.
valid_perp = 0.
if 0:
print 'testing...'
test_err, test_perp = self.pred_probs(
'test', f_log_probs,
verbose=model_options['verbose']
)
else:
test_err = 0.
test_perp = 0.
mean_ranking = 0
blue_t0 = time.time()
scores, processes, queue, rqueue, shared_params = \
metrics.compute_score(model_type='attention',
model_archive=current_params,
options=model_options,
engine=self.engine,
save_dir=save_model_dir,
beam=5, n_process=5,
whichset='both',
on_cpu=False,
processes=processes, queue=queue, rqueue=rqueue,
shared_params=shared_params, metric=metric,
one_time=False,
f_init=f_init, f_next=f_next, model=self.predict
)
valid_B1 = scores['valid']['Bleu_1']
valid_B2 = scores['valid']['Bleu_2']
valid_B3 = scores['valid']['Bleu_3']
valid_B4 = scores['valid']['Bleu_4']
valid_Rouge = scores['valid']['ROUGE_L']
valid_Cider = scores['valid']['CIDEr']
valid_meteor = scores['valid']['METEOR']
test_B1 = scores['test']['Bleu_1']
test_B2 = scores['test']['Bleu_2']
test_B3 = scores['test']['Bleu_3']
test_B4 = scores['test']['Bleu_4']
test_Rouge = scores['test']['ROUGE_L']
test_Cider = scores['test']['CIDEr']
test_meteor = scores['test']['METEOR']
print 'computing meteor/blue score used %.4f sec, '\
'blue score: %.1f, meteor score: %.1f'%(
time.time()-blue_t0, valid_B4, valid_meteor)
history_errs.append([eidx, uidx, train_perp, train_err,
valid_perp, valid_err,
test_perp, test_err,
valid_B1, valid_B2, valid_B3,
valid_B4, valid_meteor, valid_Rouge, valid_Cider,
test_B1, test_B2, test_B3,
test_B4, test_meteor, test_Rouge, test_Cider])
np.savetxt(save_model_dir+'train_valid_test.txt',
history_errs, fmt='%.3f')
print 'save validation results to %s'%save_model_dir
# save best model according to the best blue or meteor
if len(history_errs) > 1 and valid_B4 > np.array(history_errs)[:-1, 11].max():
print 'Saving to %s...'%save_model_dir,
np.savez(
save_model_dir+'model_best_blue_or_meteor.npz',
history_errs=history_errs, **best_p)
if len(history_errs) > 1 and valid_err < np.array(history_errs)[:-1, 5].min():
best_p = unzip(tparams)
bad_counter = 0
best_valid_err = valid_err
uidx_best_valid_err = uidx
print 'Saving to %s...'%save_model_dir,
np.savez(
save_model_dir+'model_best_so_far.npz',
history_errs=history_errs, **best_p)
with open('%smodel_options.pkl'%save_model_dir, 'wb') as f:
pkl.dump(model_options, f)
print 'Done'
elif len(history_errs) > 1 and valid_err >= np.array(history_errs)[:-1, 5].min():
bad_counter += 1
print 'history best ', np.array(history_errs)[:,6].min()
print 'bad_counter ', bad_counter
print 'patience ', patience
if bad_counter > patience:
print 'Early Stop!'
estop = True
break
if test_B4 > 0.48 and test_meteor > 0.32:
print 'Saving to %s...' % save_model_dir,
numpy.savez(
save_model_dir + 'model_' + str(uidx) + '.npz',
history_errs=history_errs, **current_params)
if self.channel:
self.channel.save()
print 'Train ', train_err, 'Valid ', valid_err, 'Test ', test_err, \
'best valid err so far',best_valid_err
print 'valid took %.2f sec'%(time.time() - t0_valid)
# end of validatioin
if debug:
break
if estop:
break
if debug:
break
# end for loop over minibatches
print 'This epoch has seen %d samples, train cost %.2f'%(
n_samples, np.mean(train_costs))
# end for loop over epochs
print 'Optimization ended.'
if best_p is not None:
zipp(best_p, tparams)
print 'stopped at epoch %d, minibatch %d, '\
'curent Train %.2f, current Valid %.2f, current Test %.2f '%(
eidx, uidx, np.mean(train_err), np.mean(valid_err), np.mean(test_err))
params = copy.copy(best_p)
np.savez(save_model_dir+'model_best.npz',
train_err=train_err,
valid_err=valid_err, test_err=test_err, history_errs=history_errs,
**params)
if history_errs != []:
history = np.asarray(history_errs)
best_valid_idx = history[:,6].argmin()
np.savetxt(save_model_dir+'train_valid_test.txt', history, fmt='%.4f')
print 'final best exp ', history[best_valid_idx]
return train_err, valid_err, test_err
class Model(object):
def __init__(self):
self.layers = Layers()
def init_params(self, options):
# all parameters
params = OrderedDict()
# embedding
ctx_dim_c = 4096
params['Wemb'] = utils.norm_weight(options['n_words'],
options['dim_word'])
ctx_dim = options['ctx_dim']
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_state',
nin=ctx_dim,
nout=options['dim'])
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_memory',
nin=ctx_dim,
nout=options['dim'])
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_state_c',
nin=ctx_dim_c,
nout=options['dim'])
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_memory_c',
nin=ctx_dim_c,
nout=options['dim'])
# decoder: LSTM
params = self.layers.get_layer('lstm_cond')[0](options,
params,
prefix='bo_lstm',
nin=options['dim_word'],
dim=options['dim'],
dimctx=ctx_dim)
params = self.layers.get_layer('lstm')[0](params,
nin=options['dim'],
dim=options['dim'],
prefix='to_lstm')
# readout
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_logit_bo',
nin=options['dim'],
nout=options['dim_word'])
if options['ctx2out']:
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_logit_ctx',
nin=ctx_dim,
nout=options['dim_word'])
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_logit_ctx_c',
nin=ctx_dim_c,
nout=options['dim_word'])
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_logit_to',
nin=options['dim'],
nout=options['dim_word'])
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_logit',
nin=options['dim_word'],
nout=options['n_words'])
return params
def build_model(self, tparams, options):
trng = RandomStreams(1234)
use_noise = theano.shared(numpy.float32(0.))
# description string: #words x #samples
x = tensor.matrix('x', dtype='int64')
mask = tensor.matrix('mask', dtype='float32')
# context: #samples x #annotations x dim
ctx = tensor.tensor3('ctx', dtype='float32')
mask_ctx = tensor.matrix('mask_ctx', dtype='float32')
ctx_c = tensor.tensor3('ctx_c', dtype='float32')
mask_ctx_c = tensor.matrix('mask_ctx_c', dtype='float32')
n_timesteps = x.shape[0]
n_samples = x.shape[1]
# index into the word embedding matrix, shift it forward in time
emb = tparams['Wemb'][x.flatten()].reshape(
[n_timesteps, n_samples, options['dim_word']])
emb_shifted = tensor.zeros_like(emb)
emb_shifted = tensor.set_subtensor(emb_shifted[1:], emb[:-1])
emb = emb_shifted
counts = mask_ctx.sum(-1).dimshuffle(0, 'x')
ctx_ = ctx
ctx_c_ = ctx_c
ctx0 = ctx_
ctx_mean = ctx0.sum(1) / counts
ctx0_c = ctx_c_
ctx_mean_c = ctx0_c.sum(1) / counts
# initial state/cell
init_state = self.layers.get_layer('ff')[1](tparams,
ctx_mean,
options,
prefix='ff_state',
activ='tanh')
init_memory = self.layers.get_layer('ff')[1](tparams,
ctx_mean,
options,
prefix='ff_memory',
activ='tanh')
init_state_c = self.layers.get_layer('ff')[1](tparams,
ctx_mean_c,
options,
prefix='ff_state_c',
activ='tanh')
init_memory_c = self.layers.get_layer('ff')[1](tparams,
ctx_mean_c,
options,
prefix='ff_memory_c',
activ='tanh')
init_state += init_state_c
init_memory += init_memory_c
# decoder
bo_lstm = self.layers.get_layer('lstm_cond')[1](
tparams,
emb,
options,
prefix='bo_lstm',
mask=mask,
context=ctx0,
context_c=ctx0_c,
one_step=False,
init_state=init_state,
init_memory=init_memory,
trng=trng,
use_noise=use_noise)
to_lstm = self.layers.get_layer('lstm')[1](tparams,
bo_lstm[0],
mask=mask,
one_step=False,
prefix='to_lstm')
bo_lstm_h = bo_lstm[0]
to_lstm_h = to_lstm[0]
alphas = bo_lstm[2]
alphas_c = bo_lstm[3]
ctxs = bo_lstm[4]
ctxs_c = bo_lstm[5]
weight = bo_lstm[6]
if options['use_dropout']:
bo_lstm_h = self.layers.dropout_layer(bo_lstm_h, use_noise, trng)
to_lstm_h = self.layers.dropout_layer(to_lstm_h, use_noise, trng)
# compute word probabilities
logit = self.layers.get_layer('ff')[1](tparams,
bo_lstm_h,
options,
prefix='ff_logit_bo',
activ='linear')
if options['prev2out']:
logit += emb
if options['ctx2out']:
betas = weight[:, :, 2]
#betas = betas.reshape([betas.shape[1],betas.shape[2]])
to_lstm_h *= betas[:, :, None]
ctxs_beta = self.layers.get_layer('ff')[1](tparams,
ctxs,
options,
prefix='ff_logit_ctx',
activ='linear')
ctxs_beta_c = self.layers.get_layer('ff')[1](
tparams,
ctxs_c,
options,
prefix='ff_logit_ctx_c',
activ='linear')
to_lstm_h = self.layers.get_layer('ff')[1](tparams,
to_lstm_h,
options,
prefix='ff_logit_to',
activ='linear')
logit = logit + ctxs_beta + ctxs_beta_c + to_lstm_h
logit = utils.tanh(logit)
if options['use_dropout']:
logit = self.layers.dropout_layer(logit, use_noise, trng)
# (t,m,n_words)
logit = self.layers.get_layer('ff')[1](tparams,
logit,
options,
prefix='ff_logit',
activ='linear')
logit_shp = logit.shape
# (t*m, n_words)
probs = tensor.nnet.softmax(
logit.reshape([logit_shp[0] * logit_shp[1], logit_shp[2]]))
# cost
x_flat = x.flatten() # (t*m,)
cost = -tensor.log(probs[tensor.arange(x_flat.shape[0]), x_flat] +
1e-8)
cost = cost.reshape([x.shape[0], x.shape[1]])
cost = (cost * mask).sum(0)
extra = [probs, alphas, alphas_c, weight[:, :, 0], weight[:, :, 1]]
return trng, use_noise, x, mask, ctx, mask_ctx, ctx_c, mask_ctx_c, cost, extra
def build_sampler(self, tparams, options, use_noise, trng, mode=None):
# context: #annotations x dim
ctx0 = tensor.matrix('ctx_sampler', dtype='float32')
# ctx0.tag.test_value = numpy.random.uniform(size=(50,1024)).astype('float32')
ctx_mask = tensor.vector('ctx_mask', dtype='float32')
# ctx_mask.tag.test_value = numpy.random.binomial(n=1,p=0.5,size=(50,)).astype('float32')
ctx0_c = tensor.matrix('ctx_sampler_c', dtype='float32')
# ctx0.tag.test_value = numpy.random.uniform(size=(50,1024)).astype('float32')
ctx_mask_c = tensor.vector('ctx_mask_c', dtype='float32')
ctx_ = ctx0
counts = ctx_mask.sum(-1)
ctx = ctx_
ctx_mean = ctx.sum(0) / counts
ctx_c_ = ctx0_c
counts_c = ctx_mask_c.sum(-1)
ctx_c = ctx_c_
ctx_mean_c = ctx_c.sum(0) / counts_c
# ctx_mean = ctx.mean(0)
ctx = ctx.dimshuffle('x', 0, 1)
# initial state/cell
bo_init_state = self.layers.get_layer('ff')[1](tparams,
ctx_mean,
options,
prefix='ff_state',
activ='tanh')
bo_init_memory = self.layers.get_layer('ff')[1](tparams,
ctx_mean,
options,
prefix='ff_memory',
activ='tanh')
bo_init_state_c = self.layers.get_layer('ff')[1](tparams,
ctx_mean_c,
options,
prefix='ff_state_c',
activ='tanh')
bo_init_memory_c = self.layers.get_layer('ff')[1](tparams,
ctx_mean_c,
options,
prefix='ff_memory_c',
activ='tanh')
bo_init_state += bo_init_state_c
bo_init_memory += bo_init_memory_c
to_init_state = tensor.alloc(0., options['dim'])
to_init_memory = tensor.alloc(0., options['dim'])
init_state = [bo_init_state, to_init_state]
init_memory = [bo_init_memory, to_init_memory]
print 'Building f_init...',
f_init = theano.function([ctx0, ctx_mask, ctx0_c, ctx_mask_c],
[ctx0] + init_state + init_memory,
name='f_init',
on_unused_input='ignore',
profile=False,
mode=mode)
print 'Done'
x = tensor.vector('x_sampler', dtype='int64')
init_state = [
tensor.matrix('bo_init_state', dtype='float32'),
tensor.matrix('to_init_state', dtype='float32')
]
init_memory = [
tensor.matrix('bo_init_memory', dtype='float32'),
tensor.matrix('to_init_memory', dtype='float32')
]
# if it's the first word, emb should be all zero
emb = tensor.switch(x[:, None] < 0,
tensor.alloc(0., 1, tparams['Wemb'].shape[1]),
tparams['Wemb'][x])
bo_lstm = self.layers.get_layer('lstm_cond')[1](
tparams,
emb,
options,
prefix='bo_lstm',
mask=None,
context=ctx,
context_c=ctx_c,
one_step=True,
init_state=init_state[0],
init_memory=init_memory[0],
trng=trng,
use_noise=use_noise,
mode=mode)
to_lstm = self.layers.get_layer('lstm')[1](tparams,
bo_lstm[0],
mask=None,
one_step=True,
init_state=init_state[1],
init_memory=init_memory[1],
prefix='to_lstm')
next_state = [bo_lstm[0], to_lstm[0]]
next_memory = [bo_lstm[1], to_lstm[0]]
bo_lstm_h = bo_lstm[0]
to_lstm_h = to_lstm[0]
alphas = bo_lstm[2]
alphas_c = bo_lstm[3]
ctxs = bo_lstm[4]
ctxs_c = bo_lstm[5]
weight = bo_lstm[6]
if options['use_dropout']:
bo_lstm_h = self.layers.dropout_layer(bo_lstm_h, use_noise, trng)
to_lstm_h = self.layers.dropout_layer(to_lstm_h, use_noise, trng)
logit = self.layers.get_layer('ff')[1](tparams,
bo_lstm_h,
options,
prefix='ff_logit_bo',
activ='linear')
if options['prev2out']:
logit += emb
if options['ctx2out']:
betas = weight[:, 2]
# betas = betas.reshape([betas.shape[1],betas.shape[2]])
to_lstm_h *= betas[:, None]
ctxs_beta = self.layers.get_layer('ff')[1](tparams,
ctxs,
options,
prefix='ff_logit_ctx',
activ='linear')
ctxs_beta_c = self.layers.get_layer('ff')[1](
tparams,
ctxs_c,
options,
prefix='ff_logit_ctx_c',
activ='linear')
to_lstm_h = self.layers.get_layer('ff')[1](tparams,
to_lstm_h,
options,
prefix='ff_logit_to',
activ='linear')
logit = logit + ctxs_beta + ctxs_beta_c + to_lstm_h
logit = utils.tanh(logit)
if options['use_dropout']:
logit = self.layers.dropout_layer(logit, use_noise, trng)
logit = self.layers.get_layer('ff')[1](tparams,
logit,
options,
prefix='ff_logit',
activ='linear')
logit_shp = logit.shape
next_probs = tensor.nnet.softmax(logit)
next_sample = trng.multinomial(pvals=next_probs).argmax(1)
# next word probability
print 'building f_next...'
f_next = theano.function(
[x, ctx0, ctx_mask, ctx0_c, ctx_mask_c] + init_state + init_memory,
[next_probs, next_sample] + next_state + next_memory,
name='f_next',
profile=False,
mode=mode,
on_unused_input='ignore')
print 'Done'
return f_init, f_next
def gen_sample(self,
tparams,
f_init,
f_next,
ctx0,
ctx0_c,
ctx_mask,
ctx_mask_c,
options,
trng=None,
k=1,
maxlen=30,
stochastic=False,
restrict_voc=False):
'''
ctx0: (26,1024)
ctx_mask: (26,)
restrict_voc: set the probability of outofvoc words with 0, renormalize
'''
if k > 1:
assert not stochastic, 'Beam search does not support stochastic sampling'
sample = []
sample_score = []
if stochastic:
sample_score = 0
live_k = 1
dead_k = 0
hyp_samples = [[]] * live_k
hyp_scores = numpy.zeros(live_k).astype('float32')
hyp_states = []
hyp_memories = []
# [(26,1024),(512,),(512,)]
rval = f_init(ctx0, ctx_mask, ctx0_c, ctx_mask_c)
ctx0 = rval[0]
next_state = []
next_memory = []
n_layers_lstm = 2
for lidx in xrange(n_layers_lstm):
next_state.append(rval[1 + lidx])
next_state[-1] = next_state[-1].reshape(
[live_k, next_state[-1].shape[0]])
for lidx in xrange(n_layers_lstm):
next_memory.append(rval[1 + n_layers_lstm + lidx])
next_memory[-1] = next_memory[-1].reshape(
[live_k, next_memory[-1].shape[0]])
next_w = -1 * numpy.ones((1, )).astype('int64')
# next_state: [(1,512)]
# next_memory: [(1,512)]
for ii in xrange(maxlen):
# return [(1, 50000), (1,), (1, 512), (1, 512)]
# next_w: vector
# ctx: matrix
# ctx_mask: vector
# next_state: [matrix]
# next_memory: [matrix]
rval = f_next(*([next_w, ctx0, ctx_mask, ctx0_c, ctx_mask_c] +
next_state + next_memory))
next_p = rval[0]
if restrict_voc:
raise NotImplementedError()
next_w = rval[1] # already argmax sorted
next_state = []
for lidx in xrange(n_layers_lstm):
next_state.append(rval[2 + lidx])
next_memory = []
for lidx in xrange(n_layers_lstm):
next_memory.append(rval[2 + n_layers_lstm + lidx])
if stochastic:
sample.append(next_w[0]) # take the most likely one
sample_score += next_p[0, next_w[0]]
if next_w[0] == 0:
break
else:
# the first run is (1,50000)
cand_scores = hyp_scores[:, None] - numpy.log(next_p)
cand_flat = cand_scores.flatten()
ranks_flat = cand_flat.argsort()[:(k - dead_k)]
voc_size = next_p.shape[1]
trans_indices = ranks_flat / voc_size # index of row
word_indices = ranks_flat % voc_size # index of col
costs = cand_flat[ranks_flat]
new_hyp_samples = []
new_hyp_scores = numpy.zeros(k - dead_k).astype('float32')
new_hyp_states = []
for lidx in xrange(n_layers_lstm):
new_hyp_states.append([])
new_hyp_memories = []
for lidx in xrange(n_layers_lstm):
new_hyp_memories.append([])
for idx, [ti, wi] in enumerate(zip(trans_indices,
word_indices)):
new_hyp_samples.append(hyp_samples[ti] + [wi])
new_hyp_scores[idx] = copy.copy(costs[idx])
for lidx in xrange(n_layers_lstm):
new_hyp_states[lidx].append(
copy.copy(next_state[lidx][ti]))
for lidx in xrange(n_layers_lstm):
new_hyp_memories[lidx].append(
copy.copy(next_memory[lidx][ti]))
# check the finished samples
new_live_k = 0
hyp_samples = []
hyp_scores = []
hyp_states = []
for lidx in xrange(n_layers_lstm):
hyp_states.append([])
hyp_memories = []
for lidx in xrange(n_layers_lstm):
hyp_memories.append([])
for idx in xrange(len(new_hyp_samples)):
if new_hyp_samples[idx][-1] == 0:
sample.append(new_hyp_samples[idx])
sample_score.append(new_hyp_scores[idx])
dead_k += 1
else:
new_live_k += 1
hyp_samples.append(new_hyp_samples[idx])
hyp_scores.append(new_hyp_scores[idx])
for lidx in xrange(n_layers_lstm):
hyp_states[lidx].append(new_hyp_states[lidx][idx])
for lidx in xrange(n_layers_lstm):
hyp_memories[lidx].append(
new_hyp_memories[lidx][idx])
hyp_scores = numpy.array(hyp_scores)
live_k = new_live_k
if new_live_k < 1:
break
if dead_k >= k:
break
next_w = numpy.array([w[-1] for w in hyp_samples])
next_state = []
for lidx in xrange(n_layers_lstm):
next_state.append(numpy.array(hyp_states[lidx]))
next_memory = []
for lidx in xrange(n_layers_lstm):
next_memory.append(numpy.array(hyp_memories[lidx]))
if not stochastic:
# dump every remaining one
if live_k > 0:
for idx in xrange(live_k):
sample.append(hyp_samples[idx])
sample_score.append(hyp_scores[idx])
return sample, sample_score, next_state, next_memory
def pred_probs(self, engine, whichset, f_log_probs, verbose=True):
probs = []
n_done = 0
NLL = []
L = []
if whichset == 'train':
tags = engine.train
iterator = engine.kf_train
elif whichset == 'valid':
tags = engine.valid
iterator = engine.kf_valid
elif whichset == 'test':
tags = engine.test
iterator = engine.kf_test
else:
raise NotImplementedError()
n_samples = numpy.sum([len(index) for index in iterator])
for index in iterator:
tag = [tags[i] for i in index]
x, mask, ctx, ctx_mask, ctx_c, ctx_mask_c = prepare_data(
engine, tag)
pred_probs = f_log_probs(x, mask, ctx, ctx_mask, ctx_c, ctx_mask_c)
L.append(mask.sum(0).tolist())
NLL.append((-1 * pred_probs).tolist())
probs.append(pred_probs.tolist())
n_done += len(tag)
if verbose:
sys.stdout.write('\rComputing LL on %d/%d examples' %
(n_done, n_samples))
sys.stdout.flush()
print
probs = utils.flatten_list_of_list(probs)
NLL = utils.flatten_list_of_list(NLL)
L = utils.flatten_list_of_list(L)
perp = 2**(numpy.sum(NLL) / numpy.sum(L) / numpy.log(2))
return -1 * numpy.mean(probs), perp
def sample_execute(self, engine, options, tparams, f_init, f_next, x, ctx,
ctx_c, ctx_mask, ctx_mask_c, trng):
stochastic = False
for jj in xrange(numpy.minimum(10, x.shape[1])):
sample, score, _, _ = self.gen_sample(tparams,
f_init,
f_next,
ctx[jj],
ctx_c[jj],
ctx_mask[jj],
ctx_mask_c[jj],
options,
trng=trng,
k=5,
maxlen=30,
stochastic=stochastic)
if not stochastic:
best_one = numpy.argmin(score)
sample = sample[best_one]
else:
sample = sample
print 'Truth ', jj, ': ',
for vv in x[:, jj]:
if vv == 0:
break
if vv in engine.word_idict:
print engine.word_idict[vv],
else:
print 'UNK',
print
for kk, ss in enumerate([sample]):
print 'Sample (', jj, ') ', ': ',
for vv in ss:
if vv == 0:
break
if vv in engine.word_idict:
print engine.word_idict[vv],
else:
print 'UNK',
print
class Model(object):
def __init__(self):
self.layers = Layers()
def init_params(self, options):
# all parameters
params = OrderedDict()
# embedding
params['Wemb'] = utils.norm_weight(options['vocab_size'],
options['word_dim'])
# LSTM initial states
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_state',
nin=options['ctx_dim'],
nout=options['lstm_dim'])
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_memory',
nin=options['ctx_dim'],
nout=options['lstm_dim'])
# decoder: LSTM
params = self.layers.get_layer('lstm_cond')[0](
options,
params,
prefix='bo_lstm',
nin=options['word_dim'],
dim=options['lstm_dim'],
dimctx=options['ctx_dim'])
params = self.layers.get_layer('lstm')[0](params,
nin=options['lstm_dim'],
dim=options['lstm_dim'],
prefix='to_lstm')
# readout
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_logit_bo',
nin=options['lstm_dim'],
nout=options['word_dim'])
if options['ctx2out']:
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_logit_ctx',
nin=options['ctx_dim'],
nout=options['word_dim'])
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_logit_to',
nin=options['lstm_dim'],
nout=options['word_dim'])
# MLP
params = self.layers.get_layer('ff')[0](options,
params,
prefix='ff_logit',
nin=options['word_dim'],
nout=options['vocab_size'])
return params
def build_model(self, tfparams, options, x, mask, ctx, ctx_mask):
use_noise = tf.Variable(False,
dtype=tf.bool,
trainable=False,
name="use_noise")
x_shape = tf.shape(x)
n_timesteps = x_shape[0]
n_samples = x_shape[1]
# get word embeddings
emb = tf.nn.embedding_lookup(
tfparams['Wemb'], x,
name="inputs_emb_lookup") # (num_steps,64,512)
emb_shape = tf.shape(emb)
indices = tf.expand_dims(tf.range(1, emb_shape[0]), axis=1)
emb_shifted = tf.scatter_nd(indices, emb[:-1], emb_shape)
emb = emb_shifted
# count num_frames==28
with tf.name_scope("ctx_mean"):
with tf.name_scope("counts"):
counts = tf.expand_dims(
tf.reduce_sum(ctx_mask,
axis=-1,
name="reduce_sum_ctx_mask"), 1) # (64,1)
ctx_ = ctx
ctx0 = ctx_ # (64,28,2048)
ctx_mean = tf.reduce_sum(
ctx0, axis=1, name="reduce_sum_ctx"
) / counts #mean pooling of {vi} # (64,2048)
# initial state/cell
with tf.name_scope("init_state"):
init_state = self.layers.get_layer('ff')[1](
tfparams, ctx_mean, options, prefix='ff_state',
activ='tanh') # (64,512)
with tf.name_scope("init_memory"):
init_memory = self.layers.get_layer('ff')[1](
tfparams, ctx_mean, options, prefix='ff_memory',
activ='tanh') # (64,512)
# hstltm = self.layers.build_hlstm(['bo_lstm','to_lstm'], inputs, n_timesteps, init_state, init_memory)
with tf.name_scope("bo_lstm"):
bo_lstm = self.layers.get_layer('lstm_cond')[1](
tfparams,
emb,
options,
prefix='bo_lstm',
mask=mask,
context=ctx0,
one_step=False,
init_state=init_state,
init_memory=init_memory,
use_noise=use_noise)
with tf.name_scope("to_lstm"):
to_lstm = self.layers.get_layer('lstm')[1](tfparams,
bo_lstm[0],
mask=mask,
one_step=False,
prefix='to_lstm')
bo_lstm_h = bo_lstm[0] # (t,64,512)
to_lstm_h = to_lstm[0] # (t,64,512)
alphas = bo_lstm[2] # (t,64,28)
ctxs = bo_lstm[3] # (t,64,2048)
betas = bo_lstm[4] # (t,64,)
if options['use_dropout']:
bo_lstm_h = self.layers.dropout_layer(bo_lstm_h, use_noise)
to_lstm_h = self.layers.dropout_layer(to_lstm_h, use_noise)
# compute word probabilities
logit = self.layers.get_layer('ff')[1](
tfparams, bo_lstm_h, options, prefix='ff_logit_bo',
activ='linear') # (t,64,512)*(512,512) = (t,64,512)
if options['prev2out']:
logit += emb
if options['ctx2out']:
to_lstm_h *= (1 - betas[:, :, None]) # (t,64,512)*(t,64,1)
ctxs_beta = self.layers.get_layer('ff')[1](
tfparams, ctxs, options, prefix='ff_logit_ctx',
activ='linear') # (t,64,2048)*(2048,512) = (t,64,512)
ctxs_beta += self.layers.get_layer('ff')[1](
tfparams,
to_lstm_h,
options,
prefix='ff_logit_to',
activ='linear'
) # (t,64,512)+((t,64,512)*(512,512)) = (t,64,512)
logit += ctxs_beta
logit = utils.tanh(logit) # (t,64,512)
if options['use_dropout']:
logit = self.layers.dropout_layer(logit, use_noise)
# (t,m,n_words)
logit = self.layers.get_layer('ff')[1](
tfparams, logit, options, prefix='ff_logit',
activ='linear') # (t,64,512)*(512,vocab_size) = (t,64,vocab_size)
logit_shape = tf.shape(logit)
# (t*m, n_words)
probs = tf.nn.softmax(
tf.reshape(logit,
[logit_shape[0] * logit_shape[1], logit_shape[2]
])) # (t*64, vocab_size)
# cost
x_flat = tf.reshape(x, [x_shape[0] * x_shape[1]]) # (t*m,)
x_flat_shape = tf.shape(x_flat)
gather_indices = tf.stack([tf.range(x_flat_shape[0]), x_flat],
axis=1) # (t*m,2)
cost = -tf.log(
tf.gather_nd(probs, gather_indices) +
1e-8) # (t*m,) : pick probs of each word in each timestep
cost = tf.reshape(cost, [x_shape[0], x_shape[1]]) # (t,m)
cost = tf.reduce_sum(
(cost * mask), axis=0
) # (m,) : sum across all timesteps for each element in batch
extra = [probs, alphas, betas]
return use_noise, cost, extra
def build_sampler(self,
tfparams,
options,
use_noise,
ctx0,
ctx_mask,
x,
bo_init_state_sampler,
to_init_state_sampler,
bo_init_memory_sampler,
to_init_memory_sampler,
mode=None):
# ctx: # frames x ctx_dim
ctx_ = ctx0
counts = tf.reduce_sum(ctx_mask, axis=-1) # scalar
ctx = ctx_
ctx_mean = tf.reduce_sum(ctx, axis=0) / counts # (2048,)
ctx = tf.expand_dims(ctx, 0) # (1,28,2048)
# initial state/cell
bo_init_state = self.layers.get_layer('ff')[1](tfparams,
ctx_mean,
options,
prefix='ff_state',
activ='tanh') # (512,)
bo_init_memory = self.layers.get_layer('ff')[1](tfparams,
ctx_mean,
options,
prefix='ff_memory',
activ='tanh') # (512,)
to_init_state = tf.zeros(
shape=(options['lstm_dim'], ),
dtype=tf.float32) # DOUBT : constant or not? # (512,)
to_init_memory = tf.zeros(shape=(options['lstm_dim'], ),
dtype=tf.float32) # (512,)
init_state = [bo_init_state, to_init_state]
init_memory = [bo_init_memory, to_init_memory]
print 'building f_init...',
f_init = [ctx0] + init_state + init_memory
print 'done'
init_state = [bo_init_state_sampler, to_init_state_sampler]
init_memory = [bo_init_memory_sampler, to_init_memory_sampler]
# # if it's the first word, embedding should be all zero
emb = tf.cond(
tf.reduce_any(x[:, None] < 0), lambda: tf.zeros(
shape=(1, tfparams['Wemb'].shape[1]), dtype=tf.float32),
lambda: tf.nn.embedding_lookup(tfparams['Wemb'], x)) # (m,512)
bo_lstm = self.layers.get_layer('lstm_cond')[1](
tfparams,
emb,
options,
prefix='bo_lstm',
mask=None,
context=ctx,
one_step=True,
init_state=init_state[0],
init_memory=init_memory[0],
use_noise=use_noise,
mode=mode)
to_lstm = self.layers.get_layer('lstm')[1](tfparams,
bo_lstm[0],
mask=None,
one_step=True,
init_state=init_state[1],
init_memory=init_memory[1],
prefix='to_lstm')
next_state = [bo_lstm[0], to_lstm[0]]
next_memory = [bo_lstm[1], to_lstm[0]]
bo_lstm_h = bo_lstm[0] # (1,512)
to_lstm_h = to_lstm[0] # (1,512)
alphas = bo_lstm[2] # (1,28)
ctxs = bo_lstm[3] # (1,2048)
betas = bo_lstm[4] # (1,)
if options['use_dropout']:
bo_lstm_h = self.layers.dropout_layer(bo_lstm_h, use_noise)
to_lstm_h = self.layers.dropout_layer(to_lstm_h, use_noise)
# compute word probabilities
logit = self.layers.get_layer('ff')[1](
tfparams, bo_lstm_h, options, prefix='ff_logit_bo',
activ='linear') # (1,512)*(512,512) = (1,512)
if options['prev2out']:
logit += emb
if options['ctx2out']:
to_lstm_h *= (1 - betas[:, None]) # (1,512)*(1,1) = (1,512)
ctxs_beta = self.layers.get_layer('ff')[1](
tfparams, ctxs, options, prefix='ff_logit_ctx',
activ='linear') # (1,2048)*(2048,512) = (1,512)
ctxs_beta += self.layers.get_layer('ff')[1](
tfparams,
to_lstm_h,
options,
prefix='ff_logit_to',
activ='linear') # (1,512)+((1,512)*(512,512)) = (1,512)
logit += ctxs_beta
logit = utils.tanh(logit) # (1,512)
if options['use_dropout']:
logit = self.layers.dropout_layer(logit, use_noise)
# (1,n_words)
logit = self.layers.get_layer('ff')[1](
tfparams, logit, options, prefix='ff_logit',
activ='linear') # (1,512)*(512,vocab_size) = (1,vocab_size)
next_probs = tf.nn.softmax(logit)
# next_sample = trng.multinomial(pvals=next_probs).argmax(1) # INCOMPLETE , DOUBT : why is multinomial needed?
next_sample = tf.multinomial(
next_probs, 1) # draw samples with given probabilities (1,1)
next_sample_shape = tf.shape(next_sample)
next_sample = tf.reshape(next_sample, [next_sample_shape[0]])
# next word probability
print 'building f_next...',
f_next = [next_probs, next_sample] + next_state + next_memory
print 'done'
return f_init, f_next
def gen_sample(self,
sess,
tfparams,
f_init,
f_next,
ctx0,
ctx_mask,
options,
k=1,
maxlen=30,
stochastic=False,
restrict_voc=False):
'''
ctx0: (28,2048) (f, dim_ctx)
ctx_mask: (28,) (f, )
restrict_voc: set the probability of outofvoc words with 0, renormalize
'''
if k > 1:
assert not stochastic, 'Beam search does not support stochastic sampling'
sample = []
sample_score = []
if stochastic:
sample_score = 0
live_k = 1
dead_k = 0
hyp_samples = [[]] * live_k
hyp_scores = np.zeros(live_k).astype('float32')
hyp_states = []
hyp_memories = []
# [(28,2048),(512,),(512,),(512,),(512,)]
rval = sess.run(f_init,
feed_dict={
"ctx_sampler:0": ctx0,
"ctx_mask_sampler:0": ctx_mask
})
ctx0 = rval[0]
next_state = []
next_memory = []
n_layers_lstm = 2
for lidx in xrange(n_layers_lstm):
next_state.append(rval[1 + lidx])
next_state[-1] = next_state[-1].reshape(
[live_k, next_state[-1].shape[0]])
for lidx in xrange(n_layers_lstm):
next_memory.append(rval[1 + n_layers_lstm + lidx])
next_memory[-1] = next_memory[-1].reshape(
[live_k, next_memory[-1].shape[0]])
next_w = -1 * np.ones((1, )).astype('int32')
for ii in xrange(maxlen):
# return [(1, vocab_size), (1,), (1, 512), (1, 512), (1, 512), (1, 512)]
# next_w: vector (1,)
# ctx: matrix (28, 2048)
# ctx_mask: vector (28,)
# next_state: [matrix] [(1, 512), (1, 512)]
# next_memory: [matrix] [(1, 512), (1, 512)]
rval = sess.run(f_next,
feed_dict={
"x_sampler:0": next_w,
"ctx_sampler:0": ctx0,
"ctx_mask_sampler:0": ctx_mask,
'bo_init_state_sampler:0': next_state[0],
'to_init_state_sampler:0': next_state[1],
'bo_init_memory_sampler:0': next_memory[0],
'to_init_memory_sampler:0': next_memory[1]
})
next_p = rval[0]
if restrict_voc:
raise NotImplementedError()
next_w = rval[1] # already argmax sorted
next_state = []
for lidx in xrange(n_layers_lstm):
next_state.append(rval[2 + lidx])
next_memory = []
for lidx in xrange(n_layers_lstm):
next_memory.append(rval[2 + n_layers_lstm + lidx])
if stochastic:
sample.append(next_w[0]) # take the most likely one
sample_score += next_p[0, next_w[0]]
if next_w[0] == 0:
break
else:
# the first run is (1,vocab_size)
cand_scores = hyp_scores[:, None] - np.log(next_p)
cand_flat = cand_scores.flatten()
ranks_flat = cand_flat.argsort()[:(k - dead_k)]
voc_size = next_p.shape[1]
trans_indices = ranks_flat / voc_size # index of row
word_indices = ranks_flat % voc_size # index of col
costs = cand_flat[ranks_flat]
new_hyp_samples = []
new_hyp_scores = np.zeros(k - dead_k).astype('float32')
new_hyp_states = []
for lidx in xrange(n_layers_lstm):
new_hyp_states.append([])
new_hyp_memories = []
for lidx in xrange(n_layers_lstm):
new_hyp_memories.append([])
for idx, [ti, wi] in enumerate(zip(trans_indices,
word_indices)):
new_hyp_samples.append(hyp_samples[ti] + [wi])
new_hyp_scores[idx] = copy.copy(costs[idx])
for lidx in xrange(n_layers_lstm):
new_hyp_states[lidx].append(
copy.copy(next_state[lidx][ti]))
for lidx in xrange(n_layers_lstm):
new_hyp_memories[lidx].append(
copy.copy(next_memory[lidx][ti]))
# check the finished samples
new_live_k = 0
hyp_samples = []
hyp_scores = []
hyp_states = []
for lidx in xrange(n_layers_lstm):
hyp_states.append([])
hyp_memories = []
for lidx in xrange(n_layers_lstm):
hyp_memories.append([])
for idx in xrange(len(new_hyp_samples)):
if new_hyp_samples[idx][-1] == 0:
sample.append(new_hyp_samples[idx])
sample_score.append(new_hyp_scores[idx])
dead_k += 1
else:
new_live_k += 1
hyp_samples.append(new_hyp_samples[idx])
hyp_scores.append(new_hyp_scores[idx])
for lidx in xrange(n_layers_lstm):
hyp_states[lidx].append(new_hyp_states[lidx][idx])
for lidx in xrange(n_layers_lstm):
hyp_memories[lidx].append(
new_hyp_memories[lidx][idx])
hyp_scores = np.array(hyp_scores)
live_k = new_live_k
if new_live_k < 1:
break
if dead_k >= k:
break
next_w = np.array([w[-1] for w in hyp_samples])
next_state = []
for lidx in xrange(n_layers_lstm):
next_state.append(np.array(hyp_states[lidx]))
next_memory = []
for lidx in xrange(n_layers_lstm):
next_memory.append(np.array(hyp_memories[lidx]))
if not stochastic:
# dump every remaining one
if live_k > 0:
for idx in xrange(live_k):
sample.append(hyp_samples[idx])
sample_score.append(hyp_scores[idx])
return sample, sample_score, next_state, next_memory
def pred_probs(self, sess, engine, whichset, f_log_probs, verbose=True):
probs = []
n_done = 0
NLL = []
L = []
if whichset == 'train':
tags = engine.train_data_ids
iterator = engine.kf_train
elif whichset == 'val':
tags = engine.val_data_ids
iterator = engine.kf_val
elif whichset == 'test':
tags = engine.test_data_ids
iterator = engine.kf_test
else:
raise NotImplementedError()
n_samples = np.sum([len(index) for index in iterator])
for index in iterator:
tag = [tags[i] for i in index]
x, mask, ctx, ctx_mask = prepare_data(engine, tag, mode=whichset)
pred_probs = sess.run(f_log_probs,
feed_dict={
"word_seq_x:0": x,
"word_seq_mask:0": mask,
"ctx:0": ctx,
"ctx_mask:0": ctx_mask
})
L.append(mask.sum(0).tolist())
NLL.append((-1 * pred_probs).tolist())
probs.append(pred_probs.tolist())
n_done += len(tag)
if verbose:
sys.stdout.write('\rComputing LL on %d/%d examples' %
(n_done, n_samples))
sys.stdout.flush()
print ""
probs = utils.flatten_list_of_list(probs)
NLL = utils.flatten_list_of_list(NLL)
L = utils.flatten_list_of_list(L)
perp = 2**(np.sum(NLL) / np.sum(L) / np.log(2))
return -1 * np.mean(probs), perp
def sample_execute(self, sess, engine, options, tfparams, f_init, f_next,
x, ctx, ctx_mask):
stochastic = not options['beam_search']
if stochastic:
beam = 1
else:
beam = 5
# x = (t,64)
# ctx = (64,28,2048)
# ctx_mask = (64,28)
for jj in xrange(np.minimum(10, x.shape[1])):
sample, score, _, _ = self.gen_sample(sess,
tfparams,
f_init,
f_next,
ctx[jj],
ctx_mask[jj],
options,
k=beam,
maxlen=30,
stochastic=stochastic)
if not stochastic:
best_one = np.argmin(score)
sample = sample[best_one]
else:
sample = sample
print 'Truth ', jj, ': ',
for vv in x[:, jj]:
if vv == 0:
break
if vv in engine.reverse_vocab:
print engine.reverse_vocab[vv],
else:
print 'UNK',
print ""
for kk, ss in enumerate([sample]):
print 'Sample (', jj, ') ', ': ',
for vv in ss:
if vv == 0:
break
if vv in engine.reverse_vocab:
print engine.reverse_vocab[vv],
else:
print 'UNK',
print ""
