def __init__(self, x, y, vocab_size, embed_dim, label_n):
"""
x: theano.tensor.imatrix, (minibatch size, 3)
the tree matrix of the minibatch
for each row, (node id, left child id, right child id)
y: theano.tensor.ivector, (minibatch size,)
the labels
vocab_size: int
vocabulary size, including both the words and phrases
embed_dim: int
the embedding dimension
"""
assert x.ndim == 2
assert y.ndim == 1
parent_ids = x[:, 0]
children_ids = x[:, 1:]
rng = np.random.RandomState(1234)
self.embedding = theano.shared(
value=rng.normal(0, 0.05, (vocab_size, embed_dim)),
name='embedding',
borrow=True,
)
self.rntn_layer = RNTNLayer(rng, embed_dim)
# Update the embedding by
# forwarding the embedding from bottom to up
# and getting the vector for each node in each tree
def update_embedding(child_indices, my_index, embedding):
assert child_indices.ndim == 1
assert my_index.ndim == 0
return T.switch(
T.eq(
child_indices[0], -1
), # NOTE: not using all() because it's non-differentiable
embedding, # if no child, return the word embedding
T.set_subtensor(
embedding[
my_index], # otherwise, compute the embedding of RNTN layer
self.rntn_layer.output(embedding[child_indices[0]],
embedding[child_indices[1]])))
final_embedding, updates = theano.scan(
fn=update_embedding,
sequences=[children_ids, parent_ids],
outputs_info=self.
embedding, # we should pass the whole matrix and fill in the positions if necessary
)
self.update_embedding = theano.function(
inputs=[x],
updates=[(self.embedding,
T.set_subtensor(self.embedding[parent_ids],
final_embedding[-1][parent_ids]))])
# the logistic regression layer that predicts the label
self.logreg_layer = LogisticRegression(
rng,
input=final_embedding[-1][parent_ids],
n_in=embed_dim,
n_out=label_n)
cost = self.logreg_layer.nnl(y)
params = self.logreg_layer.params + self.rntn_layer.params + [
self.embedding
]
self.params = params
param_shapes = self.logreg_layer.param_shapes + self.rntn_layer.param_shapes + [
(vocab_size, embed_dim)
]
grads = [T.grad(cost=cost, wrt=p) for p in params]
updates = build_adadelta_updates(params,
param_shapes,
grads,
epsilon=0.1)
# TODO: in this step, forward propagation is done again besides the one in `update_embedding`
# this extra computation should be avoided
self.train = theano.function(inputs=[x, y], updates=updates)
params = [theano.shared(value = param_val,
name = "param-%d" %(i),
borrow = True)
for i, param_val in enumerate(np_params)]
cost = T.sum(T.dot(params[0], params[1]))# some cost function
param_shapes = [(2,2), (2,2)]
param_grads = [T.grad(cost, param) for param in params]
assert len(np_params) == len(params) == len(param_shapes) == len(param_grads)
updates = build_adadelta_updates(params, param_shapes, param_grads,
rho = rho, epsilon = epsilon)
update = theano.function(inputs = [],
outputs = params,
updates = updates)
for i in range(n_iter):
update()
#######################
# NUMPY IMPLEMENTATION
#######################
dummy_params = [T.dmatrix('dp1'), T.dmatrix('dp2')]
def __init__(self, x, y, vocab_size, embed_dim, label_n):
"""
x: theano.tensor.imatrix, (minibatch size, 3)
the tree matrix of the minibatch
for each row, (node id, left child id, right child id)
y: theano.tensor.ivector, (minibatch size,)
the labels
vocab_size: int
vocabulary size, including both the words and phrases
embed_dim: int
the embedding dimension
"""
assert x.ndim == 2
assert y.ndim == 1
parent_ids = x[:,0]
children_ids = x[:,1:]
rng = np.random.RandomState(1234)
self.embedding = theano.shared(
value = rng.normal(0, 0.05, (vocab_size, embed_dim)),
name = 'embedding',
borrow = True,
)
self.rntn_layer = RNTNLayer(rng, embed_dim)
# Update the embedding by
# forwarding the embedding from bottom to up
# and getting the vector for each node in each tree
def update_embedding(child_indices, my_index, embedding):
assert child_indices.ndim == 1
assert my_index.ndim == 0
return T.switch(T.eq(child_indices[0], -1), # NOTE: not using all() because it's non-differentiable
embedding, # if no child, return the word embedding
T.set_subtensor(embedding[my_index], # otherwise, compute the embedding of RNTN layer
self.rntn_layer.output(embedding[child_indices[0]],
embedding[child_indices[1]])
)
)
final_embedding, updates = theano.scan(
fn = update_embedding,
sequences = [children_ids, parent_ids],
outputs_info = self.embedding, # we should pass the whole matrix and fill in the positions if necessary
)
self.update_embedding = theano.function(inputs = [x],
updates = [(self.embedding,
T.set_subtensor(self.embedding[parent_ids], final_embedding[-1][parent_ids]))])
# the logistic regression layer that predicts the label
self.logreg_layer = LogisticRegression(rng,
input = final_embedding[-1][parent_ids],
n_in = embed_dim,
n_out = label_n
)
cost = self.logreg_layer.nnl(y)
params = self.logreg_layer.params + self.rntn_layer.params + [self.embedding]
self.params = params
param_shapes = self.logreg_layer.param_shapes + self.rntn_layer.param_shapes + [(vocab_size, embed_dim)]
grads = [T.grad(cost = cost, wrt=p) for p in params]
updates = build_adadelta_updates(params, param_shapes, grads, epsilon = 0.1)
# TODO: in this step, forward propagation is done again besides the one in `update_embedding`
# this extra computation should be avoided
self.train = theano.function(inputs = [x, y],
updates = updates)
params = [theano.shared(value = param_val,
name = "param-%d" %(i),
borrow = True)
for i, param_val in enumerate(np_params)]
cost = T.sum(T.dot(params[0], params[1]))# some cost function
param_shapes = [(2,2), (2,2)]
param_grads = [T.grad(cost, param) for param in params]
assert len(np_params) == len(params) == len(param_shapes) == len(param_grads)
updates = build_adadelta_updates(params, param_shapes, param_grads,
rho = rho, epsilon = epsilon)
update = theano.function(inputs = [],
outputs = params,
updates = updates)
for i in xrange(n_iter):
update()
#######################
# NUMPY IMPLEMENTATION
#######################
dummy_params = [T.dmatrix('dp1'), T.dmatrix('dp2')]
