def _one_directional_loop(di):
# di=0, forward GRU
# di=1, backward GRU
xs_list = xs_next if di == 0 else reversed(xs_next)
layer_idx = direction * layer + di
h = hx[layer_idx]
h_list = []
for x in xs_list:
batch = x.shape[0]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
else:
h_rest = None
if layer > 0:
x = dropout.dropout(x, ratio=dropout_ratio)
gru_x = linear.linear(x, xws[layer_idx], xbs[layer_idx])
gru_h = linear.linear(h, hws[layer_idx], hbs[layer_idx])
W_r_x, W_z_x, W_x = split_axis.split_axis(gru_x, 3, axis=1)
U_r_h, U_z_h, U_x = split_axis.split_axis(gru_h, 3, axis=1)
r = sigmoid.sigmoid(W_r_x + U_r_h)
z = sigmoid.sigmoid(W_z_x + U_z_h)
h_bar = tanh.tanh(W_x + r * U_x)
h_bar = (1 - z) * h_bar + z * h
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
else:
h = h_bar
h_list.append(h_bar)
return h, h_list
def set_state(self, c, h):
h = split_axis.split_axis(h, self.num_layers, 1, True)
c = split_axis.split_axis(c, self.num_layers, 1, True)
for layer, c, h in six.moves.zip(self, c, h):
assert isinstance(h, chainer.Variable)
assert isinstance(c, chainer.Variable)
layer.set_state(c, h)
def set_state(self, c=None, h=None):
if c is not None:
c = split_axis.split_axis(c, self.num_layers, 1, True)
if h is not None:
h = split_axis.split_axis(h, self.num_layers, 1, True)
if 'set_state' in dir(self[0]):
for layer_id, layer in enumerate(self):
layer_params = inspect.getargspec(layer.set_state)[0]
if 'h' in layer_params:
if 'c' in layer_params:
if h is None:
if c is None:
layer.set_state(None, None)
else:
layer.set_state(c[layer_id], None)
else:
if c is None:
layer.set_state(None, h[layer_id])
else:
layer.set_state(c[layer_id], h[layer_id])
else:
assert c is None
if h is None:
layer.set_state(None)
else:
layer.set_state(h[layer_id])
def forward(self, *cshsx):
"""Returns new cell state and output of Child-Sum TreeLSTM.
Args:
cshsx (list of :class:`~chainer.Variable`): Variable arguments
which include all cell vectors and all output vectors of
variable children, and an input vector.
Returns:
tuple of ~chainer.Variable: Returns
:math:`(c_{new}, h_{new})`, where :math:`c_{new}` represents
new cell state vector, and :math:`h_{new}` is new output
vector.
"""
cs = cshsx[:len(cshsx) // 2]
hs = cshsx[len(cshsx) // 2:-1]
x = cshsx[-1]
assert(len(cshsx) % 2 == 1)
assert(len(cs) == len(hs))
if x is None:
if any(c is not None for c in cs):
base = [c for c in cs if c is not None][0]
elif any(h is not None for h in hs):
base = [h for h in hs if h is not None][0]
else:
raise ValueError('All inputs (cs, hs, x) are None.')
batchsize, dtype = base.shape[0], base.dtype
x = self.xp.zeros(
(batchsize, self.in_size), dtype=dtype)
W_x_in = self.W_x(x)
W_x_aio_in, W_x_f_in = split_axis.split_axis(
W_x_in, [3 * self.state_size], axis=1)
if len(hs) == 0:
aio_in = W_x_aio_in
a, i, o = split_axis.split_axis(aio_in, 3, axis=1)
c = sigmoid.sigmoid(i) * tanh.tanh(a)
h = sigmoid.sigmoid(o) * tanh.tanh(c)
return c, h
hs = self._pad_zero_nodes(
hs, (x.shape[0], self.state_size), dtype=x.dtype)
cs = self._pad_zero_nodes(
cs, (x.shape[0], self.state_size), dtype=x.dtype)
aio_in = self.W_h_aio(sum(hs)) + W_x_aio_in
W_h_fs_in = concat.concat(split_axis.split_axis(
self.W_h_f(concat.concat(hs, axis=0)), len(hs), axis=0),
axis=1)
f_in = W_h_fs_in + \
concat.concat([W_x_f_in] * len(hs), axis=1)
tree_lstm_in = concat.concat([aio_in, f_in], axis=1)
return tree_lstm.tree_lstm(*(cs + (tree_lstm_in, )))
def _one_directional_loop(di):
# di=0, forward RNN
# di=1, backward RNN
xs_list = xs_next if di == 0 else reversed(xs_next)
layer_idx = direction * layer + di
h = hx[layer_idx]
h_list = []
for x in xs_list:
batch = x.shape[0]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
else:
h_rest = None
if layer > 0:
x = dropout.dropout(x, ratio=dropout_ratio)
rnn_in = (linear.linear(x, xws[layer_idx],
xbs[layer_idx]) +
linear.linear(h, hws[layer_idx], hbs[layer_idx]))
if activation == 'tanh':
h_bar = tanh.tanh(rnn_in)
elif activation == 'relu':
h_bar = relu.relu(rnn_in)
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
else:
h = h_bar
h_list.append(h_bar)
return h, h_list
def __call__(self, c, h):
"""Updates the internal state and returns the Cell outputs.
Remember to treat this Grid cell as if its an LSTM and pass
``c`` as well as ``h``. Only parts of ``c`` will be used
depending on whether there is a LSTM or not.
Args:
c (~chainer.Variable): The previous memory information.
h (~chainer.Variable): The previous state information.
Returns:
tuple of ~chainer.Variable: Returns ``(c_new, h_new)``, where
``c_new`` represents new cell state, and ``h_new`` is updated
output. Parts of ``c_new`` will be useless.
"""
assert h is not None
assert c is not None
c = split_axis.split_axis(c, self.out_indices, 1, True)
h_list = []
h_curr = None
for layer_id, layer in enumerate(self):
layer_params = inspect.getargspec(layer)[0]
if 'c' in layer_params:
h_curr = layer(c[layer_id], h)
else:
h_curr = (c[layer_id], layer(h))
h_list.append(h_curr)
h_new = concat.concat([x[1] for x in h_list], 1)
c_new = concat.concat([x[0] for x in h_list], 1)
return c_new, h_new
def _gru(x, h, c, w, b):
xw = concat.concat([w[0], w[1], w[2]], axis=0)
hw = concat.concat([w[3], w[4], w[5]], axis=0)
xb = concat.concat([b[0], b[1], b[2]], axis=0)
hb = concat.concat([b[3], b[4], b[5]], axis=0)
gru_x = linear.linear(x, xw, xb)
gru_h = linear.linear(h, hw, hb)
W_r_x, W_z_x, W_x = split_axis.split_axis(gru_x, 3, axis=1)
U_r_h, U_z_h, U_x = split_axis.split_axis(gru_h, 3, axis=1)
r = sigmoid.sigmoid(W_r_x + U_r_h)
z = sigmoid.sigmoid(W_z_x + U_z_h)
h_bar = tanh.tanh(W_x + r * U_x)
return (1 - z) * h_bar + z * h, None
def argmax_crf1d(cost, xs):
alpha = xs[0]
alphas = []
max_inds = []
for x in xs[1:]:
batch = x.shape[0]
if alpha.shape[0] > batch:
alpha, alpha_rest = split_axis.split_axis(alpha, [batch], axis=0)
alphas.append(alpha_rest)
else:
alphas.append(None)
b_alpha, b_cost = broadcast.broadcast(alpha[..., None], cost)
scores = b_alpha + b_cost
max_ind = minmax.argmax(scores, axis=1)
max_inds.append(max_ind)
alpha = minmax.max(scores, axis=1) + x
inds = minmax.argmax(alpha, axis=1)
path = [inds.data]
for m, a in zip(max_inds[::-1], alphas[::-1]):
inds = select_item.select_item(m, inds)
if a is not None:
inds = concat.concat([inds, minmax.argmax(a, axis=1)], axis=0)
path.append(inds.data)
path.reverse()
score = minmax.max(alpha, axis=1)
for a in alphas[::-1]:
if a is None:
continue
score = concat.concat([score, minmax.max(a, axis=1)], axis=0)
return score, path
def __call__(self, x):
"""Updates the internal state and returns the LSTM outputs.
Args:
x (~chainer.Variable): A new batch from the input sequence.
Returns:
~chainer.Variable: Outputs of updated LSTM units.
"""
lstm_in = self.upward(x)
if self.h is not None:
lstm_in += self.lateral(self.h)
if self.c is None:
xp = self.xp
with cuda.get_device_from_id(self._device_id):
self.c = variable.Variable(
xp.zeros((x.shape[0], self.state_size), dtype=x.dtype))
lstm_in = reshape.reshape(
lstm_in, (len(lstm_in.data), lstm_in.shape[1] // 4, 4))
a, i, f, o = split_axis.split_axis(lstm_in, 4, 2)
a = reshape.reshape(a, (len(a.data), a.shape[1]))
i = reshape.reshape(i, (len(i.data), i.shape[1]))
f = reshape.reshape(f, (len(f.data), f.shape[1]))
o = reshape.reshape(o, (len(o.data), o.shape[1]))
peep_in_i = self.peep_i(self.c)
peep_in_f = self.peep_f(self.c)
a = tanh.tanh(a)
i = sigmoid.sigmoid(i + peep_in_i)
f = sigmoid.sigmoid(f + peep_in_f)
self.c = a * i + f * self.c
peep_in_o = self.peep_o(self.c)
o = sigmoid.sigmoid(o + peep_in_o)
self.h = o * tanh.tanh(self.c)
return self.h
def __call__(self, x):
"""Updates the internal state and returns the LSTM outputs.
Args:
x (~chainer.Variable): A new batch from the input sequence.
Returns:
~chainer.Variable: Outputs of updated LSTM units.
"""
lstm_in = self.upward(x)
if self.h is not None:
lstm_in += self.lateral(self.h)
if self.c is None:
xp = self.xp
self.c = variable.Variable(xp.zeros((x.shape[0], self.state_size), dtype=x.dtype), volatile="auto")
lstm_in = reshape.reshape(lstm_in, (len(lstm_in.data), lstm_in.shape[1] // 4, 4))
a, i, f, o = split_axis.split_axis(lstm_in, 4, 2)
a = reshape.reshape(a, (len(a.data), a.shape[1]))
i = reshape.reshape(i, (len(i.data), i.shape[1]))
f = reshape.reshape(f, (len(f.data), f.shape[1]))
o = reshape.reshape(o, (len(o.data), o.shape[1]))
peep_in_i = self.peep_i(self.c)
peep_in_f = self.peep_f(self.c)
a = tanh.tanh(a)
i = sigmoid.sigmoid(i + peep_in_i)
f = sigmoid.sigmoid(f + peep_in_f)
self.c = a * i + f * self.c
peep_in_o = self.peep_o(self.c)
o = sigmoid.sigmoid(o + peep_in_o)
self.h = o * tanh.tanh(self.c)
return self.h
def argmax_crf1d(cost, xs):
"""Computes a state that maximizes a joint probability of the given CRF.
Args:
cost (:class:`~chainer.Variable` or :ref:`ndarray`):
A :math:`K \\times K` matrix which holds transition
cost between two labels, where :math:`K` is the number of labels.
xs (list of Variable): Input vector for each label.
``len(xs)`` denotes the length of the sequence,
and each :class:`~chainer.Variable` holds a :math:`B \\times K`
matrix, where :math:`B` is mini-batch size, :math:`K` is the number
of labels.
Note that :math:`B`\\ s in all the variables are not necessary
the same, i.e., it accepts the input sequences with different
lengths.
Returns:
tuple: A tuple of :class:`~chainer.Variable` object ``s`` and a
:class:`list` ``ps``.
The shape of ``s`` is ``(B,)``, where ``B`` is the mini-batch size.
i-th element of ``s``, ``s[i]``, represents log-likelihood of i-th
data.
``ps`` is a list of :ref:`ndarray`, and denotes the state that
maximizes the point probability.
``len(ps)`` is equal to ``len(xs)``, and shape of each ``ps[i]`` is
the mini-batch size of the corresponding ``xs[i]``. That means,
``ps[i].shape == xs[i].shape[0:1]``.
"""
alpha = xs[0]
alphas = []
max_inds = []
for x in xs[1:]:
batch = x.shape[0]
if alpha.shape[0] > batch:
alpha, alpha_rest = split_axis.split_axis(alpha, [batch], axis=0)
alphas.append(alpha_rest)
else:
alphas.append(None)
b_alpha, b_cost = broadcast.broadcast(alpha[..., None], cost)
scores = b_alpha + b_cost
max_ind = minmax.argmax(scores, axis=1)
max_inds.append(max_ind)
alpha = minmax.max(scores, axis=1) + x
inds = minmax.argmax(alpha, axis=1)
path = [inds.data]
for m, a in zip(max_inds[::-1], alphas[::-1]):
inds = select_item.select_item(m, inds)
if a is not None:
inds = concat.concat([inds, minmax.argmax(a, axis=1)], axis=0)
path.append(inds.data)
path.reverse()
score = minmax.max(alpha, axis=1)
for a in alphas[::-1]:
if a is None:
continue
score = concat.concat([score, minmax.max(a, axis=1)], axis=0)
return score, path
def argmax_crf1d(cost, xs):
alpha = xs[0]
alphas = []
max_inds = []
for x in xs[1:]:
batch = x.shape[0]
if alpha.shape[0] > batch:
alpha, alpha_rest = split_axis.split_axis(alpha, [batch], axis=0)
alphas.append(alpha_rest)
else:
alphas.append(None)
b_alpha, b_cost = broadcast.broadcast(alpha[..., None], cost)
scores = b_alpha + b_cost
max_ind = minmax.argmax(scores, axis=1)
max_inds.append(max_ind)
alpha = minmax.max(scores, axis=1) + x
inds = minmax.argmax(alpha, axis=1)
path = [inds.data]
for m, a in zip(max_inds[::-1], alphas[::-1]):
inds = select_item.select_item(m, inds)
if a is not None:
inds = concat.concat([inds, minmax.argmax(a, axis=1)], axis=0)
path.append(inds.data)
path.reverse()
score = minmax.max(alpha, axis=1)
for a in alphas[::-1]:
if a is None:
continue
score = concat.concat([score, minmax.max(a, axis=1)], axis=0)
return score, path
def forward(self, x):
"""Updates the internal state and returns the LSTM outputs.
Args:
x (~chainer.Variable): A new batch from the input sequence.
Returns:
~chainer.Variable: Outputs of updated LSTM units.
"""
lstm_in = self.upward(x)
if self.h is not None:
lstm_in += self.lateral(self.h)
if self.c is None:
xp = self.xp
with chainer.using_device(self.device):
self.c = variable.Variable(
xp.zeros((len(x), self.state_size), dtype=x.dtype))
lstm_in = reshape.reshape(
lstm_in, (len(lstm_in), lstm_in.shape[1] // 4, 4))
a, i, f, o = split_axis.split_axis(lstm_in, 4, 2)
a = reshape.reshape(a, a.shape[:2])
i = reshape.reshape(i, i.shape[:2])
f = reshape.reshape(f, f.shape[:2])
o = reshape.reshape(o, o.shape[:2])
peep_in_i = self.peep_i(self.c)
peep_in_f = self.peep_f(self.c)
a = tanh.tanh(a)
i = sigmoid.sigmoid(i + peep_in_i)
f = sigmoid.sigmoid(f + peep_in_f)
self.c = a * i + f * self.c
peep_in_o = self.peep_o(self.c)
o = sigmoid.sigmoid(o + peep_in_o)
self.h = o * tanh.tanh(self.c)
return self.h
def _gru(x, h, c, w, b):
xw = concat.concat([w[0], w[1], w[2]], axis=0)
hw = concat.concat([w[3], w[4], w[5]], axis=0)
xb = concat.concat([b[0], b[1], b[2]], axis=0)
hb = concat.concat([b[3], b[4], b[5]], axis=0)
gru_x = linear.linear(x, xw, xb)
gru_h = linear.linear(h, hw, hb)
W_r_x, W_z_x, W_x = split_axis.split_axis(gru_x, 3, axis=1)
U_r_h, U_z_h, U_x = split_axis.split_axis(gru_h, 3, axis=1)
r = sigmoid.sigmoid(W_r_x + U_r_h)
z = sigmoid.sigmoid(W_z_x + U_z_h)
h_bar = tanh.tanh(W_x + r * U_x)
return (1 - z) * h_bar + z * h, None
def argmax_crf1d(cost, xs):
"""Computes a state that maximizes a joint probability of the given CRF.
Args:
cost (Variable): A :math:`K \\times K` matrix which holds transition
cost between two labels, where :math:`K` is the number of labels.
xs (list of Variable): Input vector for each label.
``len(xs)`` denotes the length of the sequence,
and each :class:`~chainer.Variable` holds a :math:`B \\times K`
matrix, where :math:`B` is mini-batch size, :math:`K` is the number
of labels.
Note that :math:`B`\\ s in all the variables are not necessary
the same, i.e., it accepts the input sequences with different
lengths.
Returns:
tuple: A tuple of :class:`~chainer.Variable` object ``s`` and a
:class:`list` ``ps``.
The shape of ``s`` is ``(B,)``, where ``B`` is the mini-batch size.
i-th element of ``s``, ``s[i]``, represents log-likelihood of i-th
data.
``ps`` is a list of :class:`numpy.ndarray` or
:class:`cupy.ndarray`, and denotes the state that maximizes the
point probability.
``len(ps)`` is equal to ``len(xs)``, and shape of each ``ps[i]`` is
the mini-batch size of the corresponding ``xs[i]``. That means,
``ps[i].shape == xs[i].shape[0:1]``.
"""
alpha = xs[0]
alphas = []
max_inds = []
for x in xs[1:]:
batch = x.shape[0]
if alpha.shape[0] > batch:
alpha, alpha_rest = split_axis.split_axis(alpha, [batch], axis=0)
alphas.append(alpha_rest)
else:
alphas.append(None)
b_alpha, b_cost = broadcast.broadcast(alpha[..., None], cost)
scores = b_alpha + b_cost
max_ind = minmax.argmax(scores, axis=1)
max_inds.append(max_ind)
alpha = minmax.max(scores, axis=1) + x
inds = minmax.argmax(alpha, axis=1)
path = [inds.data]
for m, a in zip(max_inds[::-1], alphas[::-1]):
inds = select_item.select_item(m, inds)
if a is not None:
inds = concat.concat([inds, minmax.argmax(a, axis=1)], axis=0)
path.append(inds.data)
path.reverse()
score = minmax.max(alpha, axis=1)
for a in alphas[::-1]:
if a is None:
continue
score = concat.concat([score, minmax.max(a, axis=1)], axis=0)
return score, path
def _one_directional_loop(di):
# di=0, forward RNN
# di=1, backward RNN
xs_list = xs_next if di == 0 else reversed(xs_next)
layer_idx = direction * layer + di
h = hx[layer_idx]
h_list = []
for x in xs_list:
batch = x.shape[0]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
else:
h_rest = None
if layer > 0:
x = dropout.dropout(x, ratio=dropout_ratio)
rnn_in = (
linear.linear(x, xws[layer_idx], xbs[layer_idx]) +
linear.linear(h, hws[layer_idx], hbs[layer_idx]))
if activation == 'tanh':
h_bar = tanh.tanh(rnn_in)
elif activation == 'relu':
h_bar = relu.relu(rnn_in)
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
else:
h = h_bar
h_list.append(h_bar)
return h, h_list
def __call__(self, x):
xs = split_axis.split_axis(x, x.data.shape[1], 1)
ret = []
for x in xs:
for l in self:
x = l(x)
ret.append(x)
return ret
def __call__(self, h, x):
# We compute r_x, z_x and h_x simultaneously
r_z_h_x = self.W_r_z_h(x)
r_x, z_x, h_x = split_axis.split_axis(
r_z_h_x, (self.n_units, self.n_units * 2), axis=1)
# We compute r_h and z_h simultaneously
r_z_h = self.U_r_z(h)
r_h, z_h = split_axis.split_axis(r_z_h, (self.n_units,), axis=1)
# finally we compute the output using the optimized functions
return compute_output_GRU(
z_x,
z_h,
h_x,
h,
self.U(sigmoid_a_plus_b_multiplied_by_c(r_x, r_h, h))
)
def _one_directional_loop(f, xs, h, c, w, b):
h_list = []
for x in xs:
batch = len(x)
need_split = len(h) > batch
if need_split:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
if c is not None:
c, c_rest = split_axis.split_axis(c, [batch], axis=0)
h, c = f(x, h, c, w, b)
h_list.append(h)
if need_split:
h = concat.concat([h, h_rest], axis=0)
if c is not None:
c = concat.concat([c, c_rest], axis=0)
return h, c, h_list
def _one_directional_loop(f, xs, h, c, w, b):
h_list = []
for x in xs:
batch = len(x)
need_split = len(h) > batch
if need_split:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
if c is not None:
c, c_rest = split_axis.split_axis(c, [batch], axis=0)
h, c = f(x, h, c, w, b)
h_list.append(h)
if need_split:
h = concat.concat([h, h_rest], axis=0)
if c is not None:
c = concat.concat([c, c_rest], axis=0)
return h, c, h_list
def _one_directional_loop(di):
# di=0, forward LSTM
# di=1, backward LSTM
h_list = []
c_list = []
layer_idx = direction * layer + di
h = hx[layer_idx]
c = cx[layer_idx]
if di == 0:
xs_list = xs_next
else:
xs_list = reversed(xs_next)
counter = 0
for x in xs_list:
counter += 1
batch = x.shape[0]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
c, c_rest = split_axis.split_axis(c, [batch], axis=0)
else:
h_rest = None
c_rest = None
if layer != 0:
x = dropout.dropout(x, ratio=dropout_ratio)
if counter == 4:
lstm_in = linear.linear(x, xws[layer_idx],
xbs[layer_idx])
else:
lstm_in = linear.linear(
x, xws[layer_idx], xbs[layer_idx]) + linear.linear(
h, hws[layer_idx], hbs[layer_idx])
c_bar, h_bar = lstm.lstm(c, lstm_in)
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
c = concat.concat([c_bar, c_rest], axis=0)
else:
h = h_bar
c = c_bar
h_list.append(h_bar)
c_list.append(c_bar)
return h, c, h_list, c_list
def __call__(self, x, train=True):
x = reshape.reshape(x, (len(x.data), 1) + x.data.shape[1:])
x = self.convolution(x, train)
xs = split_axis.split_axis(x, x.data.shape[2], 2)
for x in xs:
x.data = self.xp.ascontiguousarray(x.data)
for r in self.recurrent:
r.reset_state()
xs = self.recurrent(xs, train)
xs = self._linear(xs, train)
return xs
def __call__(self, x):
x = self.embed(x)
xs = split_axis.split_axis(x, x.data.shape[1], 1)
ret = []
for x in xs:
x = self.rnn1(x)
x = self.rnn2(x)
x = self.linear(x)
x = reshape.reshape(x, x.data.shape + (-1, ))
ret.append(x)
ret = concat.concat(ret, axis=2)
return ret
def forward(self, x, y):
"""Updates the internal state and returns the LSTM outputs.
Args:
x (~chainer.Variable): A new batch from the input sequence.
Returns:
~chainer.Variable: Outputs of updated LSTM units.
"""
if self.upward.has_uninitialized_params:
in_size = x.size // x.shape[0]
self.upward._initialize_params(in_size)
self._initialize_params()
batch = x.shape[0]
lstm_in = self.upward(x)
if self.h is not None:
h_size = self.h.shape[0]
if batch == 0:
h_rest = self.h
elif h_size < batch:
msg = ('The batch size of x must be equal to or less than the '
'size of the previous state h.')
raise TypeError(msg)
elif h_size > batch:
h_update, h_rest = split_axis.split_axis(
self.h, [batch], axis=0)
lstm_in += self.lateral(h_update)
else:
lstm_in += self.lateral(self.h)
if self.c is None:
xp = self.xp
self.c = variable.Variable(
xp.zeros((batch, self.state_size), dtype=x.dtype),
volatile='auto')
r = reshape.reshape(lstm_in, (len(lstm_in.data), lstm_in.data.shape[1] // 4, 4) + lstm_in.data.shape[2:])
a, i, f, o = [r[:, :, i] for i in range(4)]
# self.c, y = lstm.lstm(self.c,lstm_in)
a = tanh.tanh(a) # tanh.tanh(a)
i = sigmoid.sigmoid(i)
f = sigmoid.sigmoid(f)
o = sigmoid.sigmoid(o)
self.c = a * i + f * self.c + tanh(self.w_y(y))
self.h = o * tanh.tanh(self.c)
return self.h
def separate(x, axis=0):
"""Separates an array along a given axis.
This function separates an array along a given axis. For example, shape of
an array is ``(2, 3, 4)``. When it separates the array with ``axis=1``, it
returns three ``(2, 4)`` arrays.
This function is an inverse of :func:`chainer.functions.stack`.
Args:
x (:class:`~chainer.Variable` or :class:`numpy.ndarray` or \
:class:`cupy.ndarray`):
Variable to be separated.
A :math:`(s_1, s_2, ..., s_N)` -shaped float array.
axis (int): Axis along which variables are separated.
Returns:
tuple of chainer.Variable: Output variables.
.. seealso:: :func:`chainer.functions.stack`
.. admonition:: Example
>>> x = np.arange(6).reshape((2, 3)).astype('f')
>>> x
array([[ 0., 1., 2.],
[ 3., 4., 5.]], dtype=float32)
>>> x.shape
(2, 3)
>>> y = F.separate(x) # split along axis=0
>>> type(y)
<class 'tuple'>
>>> len(y)
2
>>> y[0].shape
(3,)
>>> y[0].data
array([ 0., 1., 2.], dtype=float32)
>>> y = F.separate(x, axis=1)
>>> len(y)
3
>>> y[0].shape
(2,)
>>> y[0].data
array([ 0., 3.], dtype=float32)
"""
shape = list(x.shape)
del shape[axis]
ys = split_axis.split_axis(x, x.shape[axis], axis, force_tuple=True)
return tuple(reshape.reshape(y, shape) for y in ys)
def separate(x, axis=0):
"""Separates an array along a given axis.
This function separates an array along a given axis. For example, shape of
an array is ``(2, 3, 4)``. When it separates the array with ``axis=1``, it
returns three ``(2, 4)`` arrays.
This function is an inverse of :func:`chainer.functions.stack`.
Args:
x (:class:`~chainer.Variable` or :class:`numpy.ndarray` or \
:class:`cupy.ndarray`):
Variable to be separated.
A :math:`(s_1, s_2, ..., s_N)` -shaped float array.
axis (int): Axis along which variables are separated.
Returns:
tuple of chainer.Variable: Output variables.
.. seealso:: :func:`chainer.functions.stack`
.. admonition:: Example
>>> x = np.arange(6).reshape((2, 3)).astype('f')
>>> x
array([[ 0., 1., 2.],
[ 3., 4., 5.]], dtype=float32)
>>> x.shape
(2, 3)
>>> y = F.separate(x) # split along axis=0
>>> isinstance(y, tuple)
True
>>> len(y)
2
>>> y[0].shape
(3,)
>>> y[0].data
array([ 0., 1., 2.], dtype=float32)
>>> y = F.separate(x, axis=1)
>>> len(y)
3
>>> y[0].shape
(2,)
>>> y[0].data
array([ 0., 3.], dtype=float32)
"""
shape = list(x.shape)
del shape[axis]
ys = split_axis.split_axis(x, x.shape[axis], axis, force_tuple=True)
return tuple(reshape.reshape(y, shape) for y in ys)
def _one_directional_loop(di):
# di=0, forward LSTM
# di=1, backward LSTM
h_list = []
c_list = []
layer_idx = direction * layer + di
h = hx[layer_idx]
c = cx[layer_idx]
if di == 0:
xs_list = xs_next
else:
xs_list = reversed(xs_next)
for x in xs_list:
batch = x.shape[0]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
c, c_rest = split_axis.split_axis(c, [batch], axis=0)
else:
h_rest = None
c_rest = None
if layer != 0:
x = dropout.dropout(x, ratio=dropout_ratio,
train=train)
lstm_in = linear.linear(x, xws[layer_idx],
xbs[layer_idx]) + \
linear.linear(h, hws[layer_idx], hbs[layer_idx])
c_bar, h_bar = lstm.lstm(c, lstm_in)
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
c = concat.concat([c_bar, c_rest], axis=0)
else:
h = h_bar
c = c_bar
h_list.append(h_bar)
c_list.append(c_bar)
return h, c, h_list, c_list
def __call__(self, x):
x = self.embed(x)
xs = split_axis.split_axis(x, x.data.shape[1], 1)
ret = []
for x in xs:
for l in self.rnns:
x = l(x)
x = dropout.dropout(x, 0.25, self.train)
for l in self.linears:
x = l(x)
x = reshape.reshape(x, x.data.shape + (-1, ))
ret.append(x)
ret = concat.concat(ret, axis=2)
return ret
def __call__(self, x):
"""Updates the internal state and returns the LSTM outputs.
Args:
x (~chainer.Variable): A new batch from the input sequence.
Returns:
~chainer.Variable: Outputs of updated LSTM units.
"""
if self.upward.has_uninitialized_params:
in_size = x.size // x.shape[0]
self.upward._initialize_params(in_size)
self._initialize_params()
batch = x.shape[0]
lstm_in = self.upward(x)
h_rest = None
if self.h is not None:
h_size = self.h.shape[0]
if batch == 0:
h_rest = self.h
elif h_size < batch:
msg = ('The batch size of x must be equal to or less than the '
'size of the previous state h.')
raise TypeError(msg)
elif h_size > batch:
h_update, h_rest = split_axis.split_axis(self.h, [batch],
axis=0)
lstm_in += self.lateral(h_update)
else:
lstm_in += self.lateral(self.h)
if self.c is None:
xp = self.xp
self.c = variable.Variable(xp.zeros((batch, self.state_size),
dtype=x.dtype),
volatile='auto')
# self.c, y = lstm.lstm(self.c, lstm_in)
c, y = lstm.lstm(self.c, lstm_in)
enable = (x.data != -1)
self.c = where(enable, c, self.c)
if self.h is not None:
y = where(enable, y, self.h)
if h_rest is None:
self.h = y
elif len(y.data) == 0:
self.h = h_rest
else:
self.h = concat.concat([y, h_rest], axis=0)
return y
def __call__(self, x):
"""Updates the internal state and returns the LSTM outputs.
Args:
x (~chainer.Variable): A new batch from the input sequence.
Returns:
~chainer.Variable: Outputs of updated LSTM units.
"""
if self.upward.has_uninitialized_params:
with cuda.get_device_from_id(self._device_id):
in_size = x.size // x.shape[0]
self.upward._initialize_params(in_size)
self._initialize_params()
batch = x.shape[0]
lstm_in = self.upward(x)
h_rest = None
if self.h is not None:
h_size = self.h.shape[0]
if batch == 0:
h_rest = self.h
elif h_size < batch:
msg = ('The batch size of x must be equal to or less than'
'the size of the previous state h.')
raise TypeError(msg)
elif h_size > batch:
h_update, h_rest = split_axis.split_axis(
self.h, [batch], axis=0)
lstm_in += self.lateral(h_update)
else:
lstm_in += self.lateral(self.h)
if self.c is None:
xp = self.xp
with cuda.get_device_from_id(self._device_id):
self.c = variable.Variable(
xp.zeros((batch, self.state_size), dtype=x.dtype),
volatile='auto')
self.c, y = lstm.lstm(self.c, lstm_in)
if h_rest is None:
self.h = y
elif len(y.data) == 0:
self.h = h_rest
else:
self.h = concat.concat([y, h_rest], axis=0)
return y
def __call__(self, x):
"""Updates the internal state and returns the LSTM outputs.
Args:
x (~chainer.Variable): A new batch from the input sequence.
Returns:
~chainer.Variable: Outputs of updated LSTM units.
"""
if self.upward.W.data is None:
with cuda.get_device_from_id(self._device_id):
in_size = functools.reduce(operator.mul, x.shape[1:], 1)
self.upward._initialize_params(in_size)
self._initialize_params()
batch = x.shape[0]
lstm_in = self.upward(x)
h_rest = None
if self.h is not None:
h_size = self.h.shape[0]
if batch == 0:
h_rest = self.h
elif h_size < batch:
msg = ('The batch size of x must be equal to or less than'
'the size of the previous state h.')
raise TypeError(msg)
elif h_size > batch:
h_update, h_rest = split_axis.split_axis(self.h, [batch],
axis=0)
lstm_in += self.lateral(h_update)
else:
lstm_in += self.lateral(self.h)
if self.c is None:
xp = self.xp
with cuda.get_device_from_id(self._device_id):
self.c = variable.Variable(
xp.zeros((batch, self.state_size), dtype=x.dtype))
self.c, y = lstm.lstm(self.c, lstm_in)
if h_rest is None:
self.h = y
elif len(y.data) == 0:
self.h = h_rest
else:
self.h = concat.concat([y, h_rest], axis=0)
return y
def forward(self, x):
"""Updates the internal state and returns the LSTM outputs.
Args:
x (~chainer.Variable): A new batch from the input sequence.
Returns:
~chainer.Variable: Outputs of updated LSTM units.
"""
if self.upward.W.array is None:
with chainer.using_device(self.device):
in_size = utils.size_of_shape(x.shape[1:])
self.upward._initialize_params(in_size)
self._initialize_params()
batch = x.shape[0]
lstm_in = self.upward(x)
h_rest = None
if self.h is not None:
h_size = self.h.shape[0]
if batch == 0:
h_rest = self.h
elif h_size < batch:
msg = ('The batch size of x must be equal to or less than'
'the size of the previous state h.')
raise TypeError(msg)
elif h_size > batch:
h_update, h_rest = split_axis.split_axis(
self.h, [batch], axis=0)
lstm_in += self.lateral(h_update)
else:
lstm_in += self.lateral(self.h)
if self.c is None:
with chainer.using_device(self.device):
self.c = variable.Variable(
self.xp.zeros((batch, self.state_size), dtype=x.dtype))
self.c, y = lstm.lstm(self.c, lstm_in)
if h_rest is None:
self.h = y
elif len(y.array) == 0:
self.h = h_rest
else:
self.h = concat.concat([y, h_rest], axis=0)
return y
def __call__(self, x):
"""Updates the internal state and returns the LSTM outputs.
Args:
x (~chainer.Variable): A new batch from the input sequence.
Returns:
~chainer.Variable: Outputs of updated LSTM units.
"""
lstm_in = self.upward(x)
if self.h is not None:
lstm_in += self.lateral(self.h)
else:
xp = self.xp
with cuda.get_device(self._device_id):
self.h = variable.Variable(
xp.zeros((len(x.data), self.state_size),
dtype=x.data.dtype),
volatile='auto')
if self.c is None:
xp = self.xp
with cuda.get_device(self._device_id):
self.c = variable.Variable(
xp.zeros((len(x.data), self.state_size),
dtype=x.data.dtype),
volatile='auto')
lstm_in = reshape.reshape(lstm_in, (len(lstm_in.data),
lstm_in.data.shape[1] // 4,
4))
a, i, f, o = split_axis.split_axis(lstm_in, 4, 2)
a = reshape.reshape(a, (len(a.data), self.state_size))
i = reshape.reshape(i, (len(i.data), self.state_size))
f = reshape.reshape(f, (len(f.data), self.state_size))
o = reshape.reshape(o, (len(o.data), self.state_size))
c_tmp = tanh.tanh(a) * sigmoid.sigmoid(i) + sigmoid.sigmoid(f) * self.c
self.c = zoneout.zoneout(self.c, c_tmp, self.c_ratio, self.train)
self.h = zoneout.zoneout(self.h,
sigmoid.sigmoid(o) * tanh.tanh(c_tmp),
self.h_ratio, self.train)
return self.h
def __call__(self, h, x):
"""Updates the internal state and returns the LSTM outputs.
Args:
x (~chainer.Variable): A new batch from the input sequence.
h (~chainer.Variable): The list of the previous cell outputs.
Returns:
~chainer.Variable: A list of the outputs (h) of the updated
LSTM units over all the layers.
"""
h_list = []
h = split_axis.split_axis(h, self.num_layers, 1, True)
h_curr = x
for layer, h in six.moves.zip(self, h):
h_curr = layer(h, h_curr)
h_list.append(h_curr)
return concat.concat(h_list, 1)
def forward(self, x):
"""Updates the internal state and returns the LSTM outputs.
Args:
x (~chainer.Variable): A new batch from the input sequence.
Returns:
~chainer.Variable: Outputs of updated LSTM units.
"""
if self.upward.W.array is None:
with chainer.using_device(self.device):
in_size = utils.size_of_shape(x.shape[1:])
self.upward._initialize_params(in_size)
self._initialize_params()
batch = x.shape[0]
lstm_in = x
# lstm_in = self.upward(x)
h_rest = None
if self.h is not None:
h_size = self.h.shape[0]
if batch == 0:
h_rest = self.h
elif h_size < batch:
msg = ('The batch size of x must be equal to or less than'
'the size of the previous state h.')
raise TypeError(msg)
elif h_size > batch:
h_update, h_rest = split_axis.split_axis(
self.h, [batch], axis=0)
lstm_in += self.lateral(h_update)
else:
lstm_in += self.lateral(self.h)
if self.c is None:
with chainer.using_device(self.device):
self.c = variable.Variable(
self.xp.zeros((batch, self.state_size), dtype=x.dtype))
self.c, = lstm(self.c, lstm_in)
return self.c
def __call__(self, batchsize):
"""....
Args:
eps (~chainer.Variable):
a wsize-length vector whose elements are drawn from
normal distribution (mean = 0, std = 1).
batchsize (~chainer.Variable):
(batch size) * (number of truncated backward gradient calculation for a training dataset)
Returns:
~chainer.Variable: Output of the linear layer.
"""
"""
self.m_hat = reshape.reshape(sum.sum(self.M)/self.M.data.shape[0], (1,1))
M, m_hat = broadcast.broadcast(self.M, self.m_hat)
self.s2_hat = sum.sum(self.S2 + (M - m_hat)*(M - m_hat))/self.M.data.shape[0]
print('m_hat.data {}'.format(self.m_hat.data))
print('self.s2_hat.data {}'.format(self.s2_hat.data))
print('self.S2.data {}'.format(self.S2.data))
print('self.M.data {}'.format(self.M.data))
print('------------------')
"""
self.fWb, loss = adaptive_weight_noise(batchsize, self.M, self.logS2,
self.use_weight_noise)
if self.nobias:
return reshape.reshape(self.fWb,
(self.out_size, self.in_size)), loss
else:
self.fW, self.fb = split_axis.split_axis(
self.fWb,
numpy.asarray([(self.in_size - 1) * self.out_size]),
axis=0)
return reshape.reshape(
self.fW, (self.out_size, self.in_size - 1)), self.fb, loss
def separate(x, axis=0):
"""Separates an array along a given axis.
This function separates an array along a given axis. For example, shape of
an array is ``(2, 3, 4)``. When it separates the array with ``axis=1``, it
returns three ``(2, 4)`` arrays.
This function is an inverse of :func:`chainer.functions.stack`.
Args:
x (chainer.Variable): Variable to be separated.
axis (int): Axis along which variables are separated.
Returns:
tuple of chainer.Variable: Output variables.
.. seealso:: :func:`chainer.functions.stack`
"""
shape = list(x.shape)
del shape[axis]
ys = split_axis.split_axis(x, x.shape[axis], axis, force_tuple=True)
return tuple(reshape.reshape(y, shape) for y in ys)
def __call__(self, c, h):
"""Updates the internal state and returns the Cell outputs.
Args:
c (~chainer.Variable): The previous memory of the Grid cell.
h (~chainer.Variable): The batched form of the previous state.
Returns:
tuple of ~chainer.Variable: Returns ``(c_new, h_new)``, where
``c_new`` represents new cell state, and ``h_new`` is updated
output of LSTM units.
"""
assert h is not None
assert c is not None
c = split_axis.split_axis(c, self.out_indices, 1, True)
h_list = []
h_curr = None
for layer_id, layer in enumerate(self):
h_curr = layer(c[layer_id], h)
h_list.append(h_curr)
h_new = concat.concat([x[1] for x in h_list], 1)
c_new = concat.concat([x[0] for x in h_list], 1)
return c_new, h_new
def __call__(self, x,Whx,Wmx,Wmh,Whm):
"""Updates the internal state and returns the LSTM outputs.
Args:
x (~chainer.Variable): A new batch from the input sequence.
Returns:
~chainer.Variable: Outputs of updated LSTM units.
"""
# if self.upward.has_uninitialized_params:
# in_size = x.size // x.shape[0]
# self.upward._initialize_params(in_size)
# self._initialize_params()
# if self.upward2.has_uninitialized_params:
# in_size = x.size // x.shape[0]
# self.upward2._initialize_params(in_size)
# self._initialize_params()
batch = x.shape[0]
# Whx = self.upward()
# Wmx = self.upward2()
factor_in = F.linear(x,Wmx)
lstm_in = F.linear(x,Whx,self.b)
h_rest = None
if self.h is not None:
h_size = self.h.shape[0]
if batch == 0:
h_rest = self.h
elif h_size < batch:
msg = ('The batch size of x must be equal to or less than the '
'size of the previous state h.')
raise TypeError(msg)
elif h_size > batch:
h_update, h_rest = split_axis.split_axis(
self.h, [batch], axis=0)
# Wmh = self.lateral1()
mult_in = F.linear(h_update,Wmh)
mult_out = mult_in*factor_in
# Whm = self.lateral2()
lstm_in += F.linear(mult_out,Whm)
else:
# Wmh = self.lateral1()
mult_in = F.linear(self.h,Wmh)
mult_out = mult_in*factor_in
# Whm = self.lateral2()
lstm_in += F.linear(mult_out,Whm)
if self.c is None:
xp = self.xp
self.c = variable.Variable(xp.zeros((batch, self.state_size), dtype=x.dtype),volatile='auto')
self.c, y = lstm.lstm(self.c, lstm_in)
if h_rest is None:
self.h = y
elif len(y.data) == 0:
self.h = h_rest
else:
self.h = concat.concat([y, h_rest], axis=0)
return y
def n_step_lstm_base(
n_layers, dropout_ratio, hx, cx, ws, bs, xs, train, use_cudnn,
use_bi_direction):
"""Base function for Stack LSTM/BiLSTM functions.
This function is used at :func:`chainer.functions.n_step_lstm` and
:func:`chainer.functions.n_step_bilstm`.
This function's behavior depends on following arguments,
``activation`` and ``use_bi_direction``.
Args:
n_layers(int): Number of layers.
dropout_ratio(float): Dropout ratio.
hx (chainer.Variable): Variable holding stacked hidden states.
Its shape is ``(S, B, N)`` where ``S`` is number of layers and is
equal to ``n_layers``, ``B`` is mini-batch size, and ``N`` is
dimention of hidden units.
cx (chainer.Variable): Variable holding stacked cell states.
It has the same shape as ``hx``.
ws (list of list of chainer.Variable): Weight matrices. ``ws[i]``
represents weights for i-th layer.
Each ``ws[i]`` is a list containing eight matrices.
``ws[i][j]`` is corresponding with ``W_j`` in the equation.
Only ``ws[0][j]`` where ``0 <= j < 4`` is ``(I, N)`` shape as they
are multiplied with input variables. All other matrices has
``(N, N)`` shape.
bs (list of list of chainer.Variable): Bias vectors. ``bs[i]``
represnents biases for i-th layer.
Each ``bs[i]`` is a list containing eight vectors.
``bs[i][j]`` is corresponding with ``b_j`` in the equation.
Shape of each matrix is ``(N,)`` where ``N`` is dimention of
hidden units.
xs (list of chainer.Variable): A list of :class:`~chainer.Variable`
holding input values. Each element ``xs[t]`` holds input value
for time ``t``. Its shape is ``(B_t, I)``, where ``B_t`` is
mini-batch size for time ``t``, and ``I`` is size of input units.
Note that this functions supports variable length sequences.
When sequneces has different lengths, sort sequences in descending
order by length, and transpose the sorted sequence.
:func:`~chainer.functions.transpose_sequence` transpose a list
of :func:`~chainer.Variable` holding sequence.
So ``xs`` needs to satisfy
``xs[t].shape[0] >= xs[t + 1].shape[0]``.
train (bool): If ``True``, this function executes dropout.
use_cudnn (bool): If ``True``, this function uses cuDNN if available.
use_bi_direction (bool): If ``True``, this function uses Bi-directional
LSTM.
Returns:
tuple: This functions returns a tuple concaining three elements,
``hy``, ``cy`` and ``ys``.
- ``hy`` is an updated hidden states whose shape is same as ``hx``.
- ``cy`` is an updated cell states whose shape is same as ``cx``.
- ``ys`` is a list of :class:`~chainer.Variable` . Each element
``ys[t]`` holds hidden states of the last layer corresponding
to an input ``xs[t]``. Its shape is ``(B_t, N)`` where ``B_t`` is
mini-batch size for time ``t``, and ``N`` is size of hidden
units. Note that ``B_t`` is the same value as ``xs[t]``.
.. seealso::
:func:`chainer.functions.n_step_lstm`
:func:`chainer.functions.n_step_bilstm`
"""
xp = cuda.get_array_module(hx, hx.data)
if use_cudnn and xp is not numpy and cuda.cudnn_enabled and \
_cudnn_version >= 5000:
states = get_random_state().create_dropout_states(dropout_ratio)
# flatten all input variables
inputs = tuple(itertools.chain(
(hx, cx),
itertools.chain.from_iterable(ws),
itertools.chain.from_iterable(bs),
xs))
if use_bi_direction:
rnn = NStepBiLSTM(n_layers, states, train=train)
else:
rnn = NStepLSTM(n_layers, states, train=train)
ret = rnn(*inputs)
hy, cy = ret[:2]
ys = ret[2:]
return hy, cy, ys
else:
direction = 2 if use_bi_direction else 1
split_size = n_layers * direction
hx = split_axis.split_axis(hx, split_size, axis=0, force_tuple=True)
hx = [reshape.reshape(h, h.shape[1:]) for h in hx]
cx = split_axis.split_axis(cx, split_size, axis=0, force_tuple=True)
cx = [reshape.reshape(c, c.shape[1:]) for c in cx]
xws = [_stack_weight([w[2], w[0], w[1], w[3]]) for w in ws]
hws = [_stack_weight([w[6], w[4], w[5], w[7]]) for w in ws]
xbs = [_stack_weight([b[2], b[0], b[1], b[3]]) for b in bs]
hbs = [_stack_weight([b[6], b[4], b[5], b[7]]) for b in bs]
xs_next = xs
hy = []
cy = []
for layer in six.moves.range(n_layers):
def _one_directional_loop(di):
# di=0, forward LSTM
# di=1, backward LSTM
h_list = []
c_list = []
layer_idx = direction * layer + di
h = hx[layer_idx]
c = cx[layer_idx]
if di == 0:
xs_list = xs_next
else:
xs_list = reversed(xs_next)
for x in xs_list:
batch = x.shape[0]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
c, c_rest = split_axis.split_axis(c, [batch], axis=0)
else:
h_rest = None
c_rest = None
if layer != 0:
x = dropout.dropout(x, ratio=dropout_ratio,
train=train)
lstm_in = linear.linear(x, xws[layer_idx],
xbs[layer_idx]) + \
linear.linear(h, hws[layer_idx], hbs[layer_idx])
c_bar, h_bar = lstm.lstm(c, lstm_in)
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
c = concat.concat([c_bar, c_rest], axis=0)
else:
h = h_bar
c = c_bar
h_list.append(h_bar)
c_list.append(c_bar)
return h, c, h_list, c_list
h, c, h_forward, c_forward = _one_directional_loop(di=0)
hy.append(h)
cy.append(c)
if use_bi_direction:
# BiLSTM
h, c, h_backward, c_backward = _one_directional_loop(di=1)
hy.append(h)
cy.append(c)
h_backward.reverse()
# concat
xs_next = [concat.concat([hfi, hbi], axis=1) for (hfi, hbi) in
zip(h_forward, h_backward)]
else:
# Uni-directional RNN
xs_next = h_forward
ys = xs_next
hy = stack.stack(hy)
cy = stack.stack(cy)
return hy, cy, tuple(ys)
def __call__(self, c=None, h=None, x=None, top_n=None):
"""Updates the internal state and returns the Cell outputs.
Args:
x (~chainer.Variable): A new batch from the input sequence.
h (~chainer.Variable): The batched form of the previous state.
Make sure that you pass the previous state if you
use stateless RNN cells
top_n (int): The number of cells from the top whose outputs
you want (default: outputs of all GRUs are returned)
When using stateless cells the states of all cells will
be returned as they will be needed for the next step
Returns:
~chainer.Variable: A concatenation of the outputs (h)
of the updated cell units over the top N layers;
by default all layers are considered.
OR
(~chainer.Variable, ~chainer.Variable):
A tuple of concatenation of the outputs (h) and memories (c)
of the updated cell units over the top N layers;
by default all layers are considered.
"""
assert x is not None
if top_n is None:
top_n = self.num_layers
if h is not None:
assert top_n is self.num_layers
h = split_axis.split_axis(h, self.num_layers, 1, True)
if c is not None:
c = split_axis.split_axis(c, self.num_layers, 1, True)
h_list = []
h_curr = x
for layer_id, layer in enumerate(self):
layer_params = inspect.getargspec(layer)[0]
if 'h' in layer_params:
if 'c' in layer_params:
if h is None:
if c is None:
h_curr = layer(None, None, h_curr)
else:
h_curr = layer(c[layer_id], None, h_curr)
else:
if c is None:
h_curr = layer(None, h[layer_id], h_curr)
else:
h_curr = layer(c[layer_id], h[layer_id], h_curr)
else:
assert c is None
if h is None:
h_curr = layer(None, h_curr)
else:
h_curr = layer(h[layer_id], h_curr)
else:
assert c is None
assert h is None
h_curr = layer(h_curr)
h_list.append(h_curr)
if len(h_list[0]) == 2:
h_out = concat.concat([y[1] for y in h_list[-top_n:]], 1)
c_out = concat.concat([y[0] for y in h_list[-top_n:]], 1)
return c_out, h_out
else:
return concat.concat(h_list[-top_n:], 1)
def n_step_lstm_base(
n_layers, dropout_ratio, hx, cx, ws, bs, xs, use_bi_direction,
**kwargs):
"""Base function for Stack LSTM/BiLSTM functions.
This function is used at :func:`chainer.functions.n_step_lstm` and
:func:`chainer.functions.n_step_bilstm`.
This function's behavior depends on following arguments,
``activation`` and ``use_bi_direction``.
Args:
n_layers(int): The number of layers.
dropout_ratio(float): Dropout ratio.
hx (~chainer.Variable): Variable holding stacked hidden states.
Its shape is ``(S, B, N)`` where ``S`` is the number of layers and
is equal to ``n_layers``, ``B`` is the mini-batch size, and ``N``
is the dimension of the hidden units.
cx (~chainer.Variable): Variable holding stacked cell states.
It has the same shape as ``hx``.
ws (list of list of :class:`~chainer.Variable`): Weight matrices.
``ws[i]`` represents the weights for the i-th layer.
Each ``ws[i]`` is a list containing eight matrices.
``ws[i][j]`` corresponds to :math:`W_j` in the equation.
Only ``ws[0][j]`` where ``0 <= j < 4`` are ``(I, N)``-shape as they
are multiplied with input variables, where ``I`` is the size of
the input and ``N`` is the dimension of the hidden units. All
other matrices are ``(N, N)``-shaped.
bs (list of list of :class:`~chainer.Variable`): Bias vectors.
``bs[i]`` represents the biases for the i-th layer.
Each ``bs[i]`` is a list containing eight vectors.
``bs[i][j]`` corresponds to :math:`b_j` in the equation.
The shape of each matrix is ``(N,)``.
xs (list of :class:`~chainer.Variable`):
A list of :class:`~chainer.Variable`
holding input values. Each element ``xs[t]`` holds input value
for time ``t``. Its shape is ``(B_t, I)``, where ``B_t`` is the
mini-batch size for time ``t``. The sequences must be transposed.
:func:`~chainer.functions.transpose_sequence` can be used to
transpose a list of :class:`~chainer.Variable`\\ s each
representing a sequence.
When sequences has different lengths, they must be
sorted in descending order of their lengths before transposing.
So ``xs`` needs to satisfy
``xs[t].shape[0] >= xs[t + 1].shape[0]``.
use_bi_direction (bool): If ``True``, this function uses Bi-directional
LSTM.
Returns:
tuple: This functions returns a tuple concaining three elements,
``hy``, ``cy`` and ``ys``.
- ``hy`` is an updated hidden states whose shape is the same as
``hx``.
- ``cy`` is an updated cell states whose shape is the same as
``cx``.
- ``ys`` is a list of :class:`~chainer.Variable` . Each element
``ys[t]`` holds hidden states of the last layer corresponding
to an input ``xs[t]``. Its shape is ``(B_t, N)`` where ``B_t`` is
the mini-batch size for time ``t``. Note that ``B_t`` is the same
value as ``xs[t]``.
.. seealso::
:func:`chainer.functions.n_step_lstm`
:func:`chainer.functions.n_step_bilstm`
"""
argument.check_unexpected_kwargs(
kwargs, train='train argument is not supported anymore. '
'Use chainer.using_config',
use_cudnn='use_cudnn argument is not supported anymore. '
'Use chainer.using_config')
argument.assert_kwargs_empty(kwargs)
xp = cuda.get_array_module(hx, hx.data)
if xp is not numpy and chainer.should_use_cudnn('>=auto', 5000):
states = get_random_state().create_dropout_states(dropout_ratio)
lengths = [len(x) for x in xs]
xs = chainer.functions.concat(xs, axis=0)
# flatten all input variables
inputs = tuple(itertools.chain(
(hx, cx),
itertools.chain.from_iterable(ws),
itertools.chain.from_iterable(bs),
(xs,)))
if use_bi_direction:
rnn = NStepBiLSTM
else:
rnn = NStepLSTM
hy, cy, ys = rnn(n_layers, states, lengths)(*inputs)
sections = numpy.cumsum(lengths[:-1])
ys = chainer.functions.split_axis(ys, sections, 0)
return hy, cy, ys
else:
direction = 2 if use_bi_direction else 1
split_size = n_layers * direction
hx = split_axis.split_axis(hx, split_size, axis=0, force_tuple=True)
hx = [reshape.reshape(h, h.shape[1:]) for h in hx]
cx = split_axis.split_axis(cx, split_size, axis=0, force_tuple=True)
cx = [reshape.reshape(c, c.shape[1:]) for c in cx]
xws = [_stack_weight([w[2], w[0], w[1], w[3]]) for w in ws]
hws = [_stack_weight([w[6], w[4], w[5], w[7]]) for w in ws]
xbs = [_stack_weight([b[2], b[0], b[1], b[3]]) for b in bs]
hbs = [_stack_weight([b[6], b[4], b[5], b[7]]) for b in bs]
xs_next = xs
hy = []
cy = []
for layer in six.moves.range(n_layers):
def _one_directional_loop(di):
# di=0, forward LSTM
# di=1, backward LSTM
h_list = []
c_list = []
layer_idx = direction * layer + di
h = hx[layer_idx]
c = cx[layer_idx]
if di == 0:
xs_list = xs_next
else:
xs_list = reversed(xs_next)
for x in xs_list:
batch = x.shape[0]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
c, c_rest = split_axis.split_axis(c, [batch], axis=0)
else:
h_rest = None
c_rest = None
if layer != 0:
x = dropout.dropout(x, ratio=dropout_ratio)
lstm_in = linear.linear(x, xws[layer_idx],
xbs[layer_idx]) + \
linear.linear(h, hws[layer_idx], hbs[layer_idx])
c_bar, h_bar = lstm.lstm(c, lstm_in)
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
c = concat.concat([c_bar, c_rest], axis=0)
else:
h = h_bar
c = c_bar
h_list.append(h_bar)
c_list.append(c_bar)
return h, c, h_list, c_list
h, c, h_forward, c_forward = _one_directional_loop(di=0)
hy.append(h)
cy.append(c)
if use_bi_direction:
# BiLSTM
h, c, h_backward, c_backward = _one_directional_loop(di=1)
hy.append(h)
cy.append(c)
h_backward.reverse()
# concat
xs_next = [concat.concat([hfi, hbi], axis=1) for (hfi, hbi) in
zip(h_forward, h_backward)]
else:
# Uni-directional RNN
xs_next = h_forward
ys = xs_next
hy = stack.stack(hy)
cy = stack.stack(cy)
return hy, cy, tuple(ys)
def crf1d(cost, xs, ys, reduce='mean'):
"""Calculates negative log-likelihood of linear-chain CRF.
It takes a transition cost matrix, a sequence of costs, and a sequence of
labels. Let :math:`c_{st}` be a transition cost from a label :math:`s` to
a label :math:`t`, :math:`x_{it}` be a cost of a label :math:`t` at
position :math:`i`, and :math:`y_i` be an expected label at position
:math:`i`. The negative log-likelihood of linear-chain CRF is defined as
.. math::
L = -\\left( \\sum_{i=1}^l x_{iy_i} + \\
\\sum_{i=1}^{l-1} c_{y_i y_{i+1}} - {\\log(Z)} \\right) ,
where :math:`l` is the length of the input sequence and :math:`Z` is the
normalizing constant called partition function.
.. note::
When you want to calculate the negative log-likelihood of sequences
which have different lengths, sort the sequences in descending order of
lengths and transpose the sequences.
For example, you have three input sequences:
>>> a1 = a2 = a3 = a4 = np.random.uniform(-1, 1, 3).astype(np.float32)
>>> b1 = b2 = b3 = np.random.uniform(-1, 1, 3).astype(np.float32)
>>> c1 = c2 = np.random.uniform(-1, 1, 3).astype(np.float32)
>>> a = [a1, a2, a3, a4]
>>> b = [b1, b2, b3]
>>> c = [c1, c2]
where ``a1`` and all other variables are arrays with ``(K,)`` shape.
Make a transpose of the sequences:
>>> x1 = np.stack([a1, b1, c1])
>>> x2 = np.stack([a2, b2, c2])
>>> x3 = np.stack([a3, b3])
>>> x4 = np.stack([a4])
and make a list of the arrays:
>>> xs = [x1, x2, x3, x4]
You need to make label sequences in the same fashion.
And then, call the function:
>>> cost = chainer.Variable(
... np.random.uniform(-1, 1, (3, 3)).astype(np.float32))
>>> ys = [np.zeros(x.shape[0:1], dtype=np.int32) for x in xs]
>>> loss = F.crf1d(cost, xs, ys)
It calculates mean of the negative log-likelihood of the three
sequences.
The output is a variable whose value depends on the value of
the option ``reduce``. If it is ``'no'``, it holds the elementwise
loss values. If it is ``'mean'``, it holds mean of the loss values.
Args:
cost (Variable): A :math:`K \\times K` matrix which holds transition
cost between two labels, where :math:`K` is the number of labels.
xs (list of Variable): Input vector for each label.
``len(xs)`` denotes the length of the sequence,
and each :class:`~chainer.Variable` holds a :math:`B \\times K`
matrix, where :math:`B` is mini-batch size, :math:`K` is the number
of labels.
Note that :math:`B`\\ s in all the variables are not necessary
the same, i.e., it accepts the input sequences with different
lengths.
ys (list of Variable): Expected output labels. It needs to have the
same length as ``xs``. Each :class:`~chainer.Variable` holds a
:math:`B` integer vector.
When ``x`` in ``xs`` has the different :math:`B`, correspoding
``y`` has the same :math:`B`. In other words, ``ys`` must satisfy
``ys[i].shape == xs[i].shape[0:1]`` for all ``i``.
reduce (str): Reduction option. Its value must be either
``'mean'`` or ``'no'``. Otherwise, :class:`ValueError` is raised.
Returns:
~chainer.Variable: A variable holding the average negative
log-likelihood of the input sequences.
.. note::
See detail in the original paper: `Conditional Random Fields:
Probabilistic Models for Segmenting and Labeling Sequence Data
<https://repository.upenn.edu/cis_papers/159/>`_.
"""
if reduce not in ('mean', 'no'):
raise ValueError(
"only 'mean' and 'no' are valid for 'reduce', but '%s' is "
'given' % reduce)
assert xs[0].shape[1] == cost.shape[0]
n_label = cost.shape[0]
n_batch = xs[0].shape[0]
alpha = xs[0]
alphas = []
for x in xs[1:]:
batch = x.shape[0]
if alpha.shape[0] > batch:
alpha, alpha_rest = split_axis.split_axis(alpha, [batch], axis=0)
alphas.append(alpha_rest)
b_alpha, b_cost = broadcast.broadcast(alpha[..., None], cost)
alpha = logsumexp.logsumexp(b_alpha + b_cost, axis=1) + x
if len(alphas) > 0:
alphas.append(alpha)
alpha = concat.concat(alphas[::-1], axis=0)
logz = logsumexp.logsumexp(alpha, axis=1)
cost = reshape.reshape(cost, (cost.size, 1))
score = select_item.select_item(xs[0], ys[0])
scores = []
for x, y, y_prev in zip(xs[1:], ys[1:], ys[:-1]):
batch = x.shape[0]
if score.shape[0] > batch:
y_prev, _ = split_axis.split_axis(y_prev, [batch], axis=0)
score, score_rest = split_axis.split_axis(score, [batch], axis=0)
scores.append(score_rest)
score += (select_item.select_item(x, y) + reshape.reshape(
embed_id.embed_id(y_prev * n_label + y, cost), (batch,)))
if len(scores) > 0:
scores.append(score)
score = concat.concat(scores[::-1], axis=0)
loss = logz - score
if reduce == 'mean':
return _sum.sum(loss) / n_batch
else:
return loss
def _one_directional_loop(di):
# di=0, forward GRU
# di=1, backward GRU
xs_list = xs_next if di == 0 else reversed(xs_next)
layer_idx = direction * layer + di
h = h0[layer_idx]
# h:d_bar_s_1
# h_bar:d_s
'''
print(len(xs_list))
print(len(xs_list[0]))
print(len(xs_list[0][0]))
'''
h_list = []
h_bar_list = []
c_s_list = []
z_s_list = []
for x in xs_list:
batch = x.shape[0]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
else:
h_rest = None
if layer > 0:
x = dropout.dropout(x, ratio=dropout_ratio)
gru_x = linear.linear(x, xws[layer_idx], xbs[layer_idx])
gru_h = linear.linear(h, hws[layer_idx], hbs[layer_idx])
W_r_x, W_z_x, W_x = split_axis.split_axis(gru_x, 3, axis=1)
U_r_h, U_z_h, U_x = split_axis.split_axis(gru_h, 3, axis=1)
r = sigmoid.sigmoid(W_r_x + U_r_h)
z = sigmoid.sigmoid(W_z_x + U_z_h)
h_bar = tanh.tanh(W_x + r * U_x)
h_bar = (1 - z) * h_bar + z * h
phi_d = linear.linear(h_bar, W2, B2)
'''
print(type(phi_ht), len(phi_ht))
print(type(phi_ht[0]), len(phi_ht[0]))
print(type(phi_ht[0][0]), len(phi_ht[0][0]))
print(type(phi_d), len(phi_d))
print(type(phi_d[0]), len(phi_d[0]), phi_d[0].shape)
'''
#phi_ht_len = [t.shape[1] for t in phi_ht]
#phi_ht_section = np.cumsum(phi_ht_len[:-1])
#concat_phi_ht = F.concat(phi_ht, axis=1)
#concat_phi_d = [F.concat([phi_d[i]]*phi_ht_len[i], axis=0) for i in range(batch)]
#concat_phi_d = F.concat(concat_phi_d, axis=0)
#concat_phi_d = F.concat(F.transpose(phi_d), axis=0)
u_st = list(
map(
lambda x, y: reshape.reshape((linear.linear(
x, reshape.reshape(y, (1, len(y))))),
(len(x), )), phi_ht,
phi_d)) #(4)
sum_u = list(map(F.sum, u_st))
alpha_st = list(
map(lambda x, y: x / F.broadcast_to(y, x.shape), u_st,
sum_u)) #(3)
z_s = list(map(F.argmax, alpha_st))
z_s = list(map(lambda x: F.broadcast_to(x, (1, )), z_s))
z_s = F.concat(z_s, axis=0)
'''
print(type(alpha_st),len(alpha_st))
print(type(alpha_st[0]),len(alpha_st[0]))
print(alpha_st[0].shape)
print(ht[0].shape)
'''
c_s = list(
map(
lambda x, y: F.sum(F.broadcast_to(
reshape.reshape(x,
(x.shape[0], 1)), y.shape) * y,
axis=0), alpha_st, ht)) #(2)
c_s_2d = list(
map(lambda x: reshape.reshape(x, (1, len(x))), c_s))
concat_c_s = F.concat(c_s_2d, axis=0)
c_s = list(
map(lambda x: F.broadcast_to(x, (1, len(x))), c_s))
c_s = F.concat(c_s, axis=0)
'''
print(type(c_s), len(c_s))
print(type(c_s[0]), len(c_s[0]), c_s[0].shape)
'''
h = F.relu(
linear.linear(F.concat([concat_c_s, h_bar], axis=1),
W3, B3))
h_list.append(h)
h_bar_list.append(h_bar)
c_s_list.append(c_s)
z_s_list.append(z_s)
#単語数の違いを担保
if h_rest is not None:
h = concat.concat([h, h_rest], axis=0)
h_bar = concat.concat([h_bar, h_rest], axis=0)
return h_list, h_bar_list, c_s_list, z_s_list
def n_step_lstm(n_layers,
dropout_ratio,
hx,
cx,
ws,
bs,
xs,
train=True,
use_cudnn=True):
"""Stacked Long Short-Term Memory function for sequence inputs.
This function calculates stacked LSTM with sequences. This function gets
an initial hidden state :math:`h_0`, an initial cell state :math:`c_0`,
an input sequence :math:`x`, weight matrices :math:`W`, and bias vectors
:math:`b`.
This function calculates hidden states :math:`h_t` and :math:`c_t` for each
time :math:`t` from input :math:`x_t`.
.. math::
i_t = \sigma(W_0 x_t + W_4 h_{t-1} + b_0 + b_4)
f_t = \sigma(W_1 x_t + W_5 h_{t-1} + b_1 + b_5)
o_t = \sigma(W_2 x_t + W_6 h_{t-1} + b_2 + b_6)
a_t = \tanh(W_3 x_t + W_7 h_{t-1} + b_3 + b_7)
c_t = f_t \dot c_{t-1} + i_t \dot a_t
h_t = o_t \dot \tanh(c_t)
As the function accepts a sequence, it calculates :math:`h_t` for all
:math:`t` with one call. Eight weight matrices and eight bias vectors are
required for each layers. So, when :math:`S` layers exists, you need to
prepare :math:`8S` weigth matrices and :math:`8S` bias vectors.
If the number of layers ``n_layers`` is greather than :math:`1`, input
of ``k``-th layer is hidden state ``h_t`` of ``k-1``-th layer.
Note that all input variables except first layer may have different shape
from the first layer.
Args:
n_layers(int): Number of layers.
dropout_ratio(float): Dropout ratio.
hx (chainer.Variable): Variable holding stacked hidden states.
Its shape is ``(S, B, N)`` where ``S`` is number of layers and is
equal to ``n_layers``, ``B`` is mini-batch size, and ``N`` is
dimention of hidden units.
cx (chainer.Variable): Variable holding stacked cell states.
It has the same shape as ``hx``.
ws (list of list of chainer.Variable): Weight matrices. ``ws[i]``
represents weights for i-th layer.
Each ``ws[i]`` is a list containing eight matrices.
``ws[i][j]`` is corresponding with ``W_j`` in the equation.
Only ``ws[0][j]`` where ``0 <= j < 4`` is ``(I, N)`` shape as they
are multiplied with input variables. All other matrices has
``(N, N)`` shape.
bs (list of list of chainer.Variable): Bias vectors. ``bs[i]``
represnents biases for i-th layer.
Each ``bs[i]`` is a list containing eight vectors.
``bs[i][j]`` is corresponding with ``b_j`` in the equation.
Shape of each matrix is ``(N,)`` where ``N`` is dimention of
hidden units.
xs (list of chainer.Variable): A list of :class:`chainer.Variable`
holding input values. Each element ``xs[t]`` holds input value
for time ``t``. Its shape is ``(B_t, I)``, where ``B_t`` is
mini-batch size for time ``t``, and ``I`` is size of input units.
Note that this functions supports variable length sequences.
When sequneces has different lengths, sort sequences in descending
order by length, and transpose the sorted sequence.
:func:`~chainer.functions.transpose_sequence` transpose a list
of :func:`~chainer.Variable` holding sequence.
So ``xs`` needs to satisfy
``xs[t].shape[0] >= xs[t + 1].shape[0]``.
train (bool): If ``True``, this function executes dropout.
use_cudnn (bool): If ``True``, this function uses cuDNN if available.
Returns:
tuple: This functions returns a tuple concaining three elements,
``hy``, ``cy`` and ``ys``.
- ``hy`` is an updated hidden states whose shape is same as ``hx``.
- ``cy`` is an updated cell states whose shape is same as ``cx``.
- ``ys`` is a list of :class:~chainer.Variable. Each element
``ys[t]`` holds hidden states of the last layer corresponding
to an input ``xs[t]``. Its shape is ``(B_t, N)`` where ``B_t`` is
mini-batch size for time ``t``, and ``N`` is size of hidden
units. Note that ``B_t`` is the same value as ``xs[t]``.
.. seealso::
:func:`chainer.functions.lstm`
"""
xp = cuda.get_array_module(hx, hx.data)
if use_cudnn and xp is not numpy and cuda.cudnn_enabled and \
_cudnn_version >= 5000:
states = get_random_state().create_dropout_states(dropout_ratio)
# flatten all input variables
inputs = tuple(
itertools.chain((hx, cx), itertools.chain.from_iterable(ws),
itertools.chain.from_iterable(bs), xs))
rnn = NStepLSTM(n_layers, states, train=train)
ret = rnn(*inputs)
hy, cy = ret[:2]
ys = ret[2:]
return hy, cy, ys
else:
hx = split_axis.split_axis(hx, n_layers, axis=0, force_tuple=True)
hx = [reshape.reshape(h, h.shape[1:]) for h in hx]
cx = split_axis.split_axis(cx, n_layers, axis=0, force_tuple=True)
cx = [reshape.reshape(c, c.shape[1:]) for c in cx]
xws = [_stack_weight([w[2], w[0], w[1], w[3]]) for w in ws]
hws = [_stack_weight([w[6], w[4], w[5], w[7]]) for w in ws]
xbs = [_stack_weight([b[2], b[0], b[1], b[3]]) for b in bs]
hbs = [_stack_weight([b[6], b[4], b[5], b[7]]) for b in bs]
ys = []
for x in xs:
batch = x.shape[0]
h_next = []
c_next = []
for layer in six.moves.range(n_layers):
h = hx[layer]
c = cx[layer]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
c, c_rest = split_axis.split_axis(c, [batch], axis=0)
else:
h_rest = None
x = dropout.dropout(x, ratio=dropout_ratio, train=train)
h = dropout.dropout(h, ratio=dropout_ratio, train=train)
lstm_in = linear.linear(x, xws[layer], xbs[layer]) + \
linear.linear(h, hws[layer], hbs[layer])
c_bar, h_bar = lstm.lstm(c, lstm_in)
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
c = concat.concat([c_bar, c_rest], axis=0)
else:
h = h_bar
c = c_bar
h_next.append(h)
c_next.append(c)
x = h_bar
hx = h_next
cx = c_next
ys.append(x)
hy = stack.stack(hx)
cy = stack.stack(cx)
return hy, cy, tuple(ys)
def n_step_gru_base(n_layers, dropout_ratio, hx, ws, bs, xs, use_bi_direction,
**kwargs):
"""n_step_gru_base(n_layers, dropout_ratio, hx, ws, bs, xs, use_bi_direction)
Base function for Stack GRU/BiGRU functions.
This function is used at :func:`chainer.functions.n_step_bigru` and
:func:`chainer.functions.n_step_gru`.
This function's behavior depends on argument ``use_bi_direction``.
.. warning::
``train`` and ``use_cudnn`` arguments are not supported anymore since
v2.
Instead, use ``chainer.using_config('train', train)`` and
``chainer.using_config('use_cudnn', use_cudnn)`` respectively.
See :func:`chainer.using_config`.
Args:
n_layers(int): Number of layers.
dropout_ratio(float): Dropout ratio.
hx (chainer.Variable): Variable holding stacked hidden states.
Its shape is ``(S, B, N)`` where ``S`` is number of layers and is
equal to ``n_layers``, ``B`` is mini-batch size, and ``N`` is
dimension of hidden units. Because of bi-direction, the
first dimension length is ``2S``.
ws (list of list of chainer.Variable): Weight matrices. ``ws[i]``
represents weights for i-th layer.
Each ``ws[i]`` is a list containing six matrices.
``ws[i][j]`` is corresponding with ``W_j`` in the equation.
Only ``ws[0][j]`` where ``0 <= j < 3`` is ``(I, N)`` shape as they
are multiplied with input variables. All other matrices has
``(N, N)`` shape.
bs (list of list of chainer.Variable): Bias vectors. ``bs[i]``
represnents biases for i-th layer.
Each ``bs[i]`` is a list containing six vectors.
``bs[i][j]`` is corresponding with ``b_j`` in the equation.
Shape of each matrix is ``(N,)`` where ``N`` is dimension of
hidden units.
xs (list of chainer.Variable): A list of :class:`~chainer.Variable`
holding input values. Each element ``xs[t]`` holds input value
for time ``t``. Its shape is ``(B_t, I)``, where ``B_t`` is
mini-batch size for time ``t``, and ``I`` is size of input units.
Note that this functions supports variable length sequences.
When sequneces has different lengths, sort sequences in descending
order by length, and transpose the sorted sequence.
:func:`~chainer.functions.transpose_sequence` transpose a list
of :func:`~chainer.Variable` holding sequence.
So ``xs`` needs to satisfy
``xs[t].shape[0] >= xs[t + 1].shape[0]``.
activation (str): Activation function name.
Please select ``tanh`` or ``relu``.
use_bi_direction (bool): If ``True``, this function uses
Bi-direction GRU.
.. seealso::
:func:`chainer.functions.n_step_rnn`
:func:`chainer.functions.n_step_birnn`
""" # NOQA
argument.check_unexpected_kwargs(
kwargs,
train='train argument is not supported anymore. '
'Use chainer.using_config',
use_cudnn='use_cudnn argument is not supported anymore. '
'Use chainer.using_config')
argument.assert_kwargs_empty(kwargs)
xp = cuda.get_array_module(hx, hx.data)
if xp is not numpy and chainer.should_use_cudnn('>=auto', 5000):
states = get_random_state().create_dropout_states(dropout_ratio)
# flatten all input variables
inputs = tuple(
itertools.chain((hx, ), itertools.chain.from_iterable(ws),
itertools.chain.from_iterable(bs), xs))
if use_bi_direction:
rnn = NStepBiGRU(n_layers, states)
else:
rnn = NStepGRU(n_layers, states)
ret = rnn(*inputs)
hy, = ret[:1]
ys = ret[1:]
return hy, ys
else:
direction = 2 if use_bi_direction else 1
hx = split_axis.split_axis(hx,
n_layers * direction,
axis=0,
force_tuple=True)
hx = [reshape.reshape(h, h.shape[1:]) for h in hx]
xws = [concat.concat([w[0], w[1], w[2]], axis=0) for w in ws]
hws = [concat.concat([w[3], w[4], w[5]], axis=0) for w in ws]
xbs = [concat.concat([b[0], b[1], b[2]], axis=0) for b in bs]
hbs = [concat.concat([b[3], b[4], b[5]], axis=0) for b in bs]
xs_next = xs
hy = []
for layer in six.moves.range(n_layers):
def _one_directional_loop(di):
# di=0, forward GRU
# di=1, backward GRU
xs_list = xs_next if di == 0 else reversed(xs_next)
layer_idx = direction * layer + di
h = hx[layer_idx]
h_list = []
for x in xs_list:
batch = x.shape[0]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
else:
h_rest = None
if layer > 0:
x = dropout.dropout(x, ratio=dropout_ratio)
gru_x = linear.linear(x, xws[layer_idx], xbs[layer_idx])
gru_h = linear.linear(h, hws[layer_idx], hbs[layer_idx])
W_r_x, W_z_x, W_x = split_axis.split_axis(gru_x, 3, axis=1)
U_r_h, U_z_h, U_x = split_axis.split_axis(gru_h, 3, axis=1)
r = sigmoid.sigmoid(W_r_x + U_r_h)
z = sigmoid.sigmoid(W_z_x + U_z_h)
h_bar = tanh.tanh(W_x + r * U_x)
h_bar = (1 - z) * h_bar + z * h
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
else:
h = h_bar
h_list.append(h_bar)
return h, h_list
# Forward GRU
h, h_forward = _one_directional_loop(di=0)
hy.append(h)
if use_bi_direction:
# Backward GRU
h, h_backward = _one_directional_loop(di=1)
h_backward.reverse()
# Concat
xs_next = [
concat.concat([hfi, hbi], axis=1)
for (hfi, hbi) in six.moves.zip(h_forward, h_backward)
]
hy.append(h)
else:
# Uni-directional GRU
xs_next = h_forward
ys = xs_next
hy = stack.stack(hy)
return hy, tuple(ys)
def crf1d(cost, xs, ys, reduce='mean'):
"""Calculates negative log-likelihood of linear-chain CRF.
It takes a transition cost matrix, a sequence of costs, and a sequence of
labels. Let :math:`c_{st}` be a transition cost from a label :math:`s` to
a label :math:`t`, :math:`x_{it}` be a cost of a label :math:`t` at
position :math:`i`, and :math:`y_i` be an expected label at position
:math:`i`. The negative log-likelihood of linear-chain CRF is defined as
.. math::
L = -\\left( \\sum_{i=1}^l x_{iy_i} + \\
\\sum_{i=1}^{l-1} c_{y_i y_{i+1}} - {\\log(Z)} \\right) ,
where :math:`l` is the length of the input sequence and :math:`Z` is the
normalizing constant called partition function.
.. note::
When you want to calculate the negative log-likelihood of sequences
which have different lengths, sort the sequences in descending order of
lengths and transpose the sequences.
For example, you have three input sequences:
>>> a1 = a2 = a3 = a4 = np.random.uniform(-1, 1, 3).astype('f')
>>> b1 = b2 = b3 = np.random.uniform(-1, 1, 3).astype('f')
>>> c1 = c2 = np.random.uniform(-1, 1, 3).astype('f')
>>> a = [a1, a2, a3, a4]
>>> b = [b1, b2, b3]
>>> c = [c1, c2]
where ``a1`` and all other variables are arrays with ``(K,)`` shape.
Make a transpose of the sequences:
>>> x1 = np.stack([a1, b1, c1])
>>> x2 = np.stack([a2, b2, c2])
>>> x3 = np.stack([a3, b3])
>>> x4 = np.stack([a4])
and make a list of the arrays:
>>> xs = [x1, x2, x3, x4]
You need to make label sequences in the same fashion.
And then, call the function:
>>> cost = chainer.Variable(
... np.random.uniform(-1, 1, (3, 3)).astype('f'))
>>> ys = [np.zeros(x.shape[0:1], dtype='i') for x in xs]
>>> loss = F.crf1d(cost, xs, ys)
It calculates mean of the negative log-likelihood of the three
sequences.
The output is a variable whose value depends on the value of
the option ``reduce``. If it is ``'no'``, it holds the elementwise
loss values. If it is ``'mean'``, it holds mean of the loss values.
Args:
cost (Variable): A :math:`K \\times K` matrix which holds transition
cost between two labels, where :math:`K` is the number of labels.
xs (list of Variable): Input vector for each label.
``len(xs)`` denotes the length of the sequence,
and each :class:`~chainer.Variable` holds a :math:`B \\times K`
matrix, where :math:`B` is mini-batch size, :math:`K` is the number
of labels.
Note that :math:`B` s in all the variables are not necessary
the same, i.e., it accepts the input sequences with different
lengths.
ys (list of Variable): Expected output labels. It needs to have the
same length as ``xs``. Each :class:`~chainer.Variable` holds a
:math:`B` integer vector.
When ``x`` in ``xs`` has the different :math:`B`, correspoding
``y`` has the same :math:`B`. In other words, ``ys`` must satisfy
``ys[i].shape == xs[i].shape[0:1]`` for all ``i``.
reduce (str): Reduction option. Its value must be either
``'mean'`` or ``'no'``. Otherwise, :class:`ValueError` is raised.
Returns:
~chainer.Variable: A variable holding the average negative
log-likelihood of the input sequences.
.. note::
See detail in the original paper: `Conditional Random Fields:
Probabilistic Models for Segmenting and Labeling Sequence Data
<http://repository.upenn.edu/cis_papers/159/>`_.
"""
if reduce not in ('mean', 'no'):
raise ValueError(
"only 'mean' and 'no' are valid for 'reduce', but '%s' is "
'given' % reduce)
assert xs[0].shape[1] == cost.shape[0]
n_label = cost.shape[0]
n_batch = xs[0].shape[0]
alpha = xs[0]
alphas = []
for x in xs[1:]:
batch = x.shape[0]
if alpha.shape[0] > batch:
alpha, alpha_rest = split_axis.split_axis(alpha, [batch], axis=0)
alphas.append(alpha_rest)
b_alpha, b_cost = broadcast.broadcast(alpha[..., None], cost)
alpha = logsumexp.logsumexp(b_alpha + b_cost, axis=1) + x
if len(alphas) > 0:
alphas.append(alpha)
alpha = concat.concat(alphas[::-1], axis=0)
logz = logsumexp.logsumexp(alpha, axis=1)
cost = reshape.reshape(cost, (cost.size, 1))
score = select_item.select_item(xs[0], ys[0])
scores = []
for x, y, y_prev in zip(xs[1:], ys[1:], ys[:-1]):
batch = x.shape[0]
if score.shape[0] > batch:
y_prev, _ = split_axis.split_axis(y_prev, [batch], axis=0)
score, score_rest = split_axis.split_axis(score, [batch], axis=0)
scores.append(score_rest)
score += (
select_item.select_item(x, y) +
reshape.reshape(embed_id.embed_id(y_prev * n_label + y, cost),
(batch, )))
if len(scores) > 0:
scores.append(score)
score = concat.concat(scores[::-1], axis=0)
loss = logz - score
if reduce == 'mean':
return _sum.sum(loss) / n_batch
else:
return loss
def n_step_rnn_base(n_layers, dropout_ratio, hx, ws, bs, xs,
activation, use_bi_direction, **kwargs):
"""n_step_rnn_base(n_layers, dropout_ratio, hx, ws, bs, xs, activation, use_bi_direction)
Base function for Stack RNN/BiRNN functions.
This function is used at :func:`chainer.functions.n_step_birnn` and
:func:`chainer.functions.n_step_rnn`.
This function's behavior depends on following arguments,
``activation`` and ``use_bi_direction``.
.. warning::
``train`` and ``use_cudnn`` arguments are not supported anymore since
v2.
Instead, use ``chainer.using_config('train', train)`` and
``chainer.using_config('use_cudnn', use_cudnn)`` respectively.
See :func:`chainer.using_config`.
Args:
n_layers(int): Number of layers.
dropout_ratio(float): Dropout ratio.
hx (chainer.Variable): Variable holding stacked hidden states.
Its shape is ``(S, B, N)`` where ``S`` is number of layers and is
equal to ``n_layers``, ``B`` is mini-batch size, and ``N`` is
dimention of hidden units.
ws (list of list of chainer.Variable): Weight matrices. ``ws[i]``
represents weights for i-th layer.
Each ``ws[i]`` is a list containing two matrices.
``ws[i][j]`` is corresponding with ``W_j`` in the equation.
Only ``ws[0][j]`` where ``0 <= j < 1`` is ``(I, N)`` shape as they
are multiplied with input variables. All other matrices has
``(N, N)`` shape.
bs (list of list of chainer.Variable): Bias vectors. ``bs[i]``
represnents biases for i-th layer.
Each ``bs[i]`` is a list containing two vectors.
``bs[i][j]`` is corresponding with ``b_j`` in the equation.
Shape of each matrix is ``(N,)`` where ``N`` is dimention of
hidden units.
xs (list of chainer.Variable): A list of :class:`~chainer.Variable`
holding input values. Each element ``xs[t]`` holds input value
for time ``t``. Its shape is ``(B_t, I)``, where ``B_t`` is
mini-batch size for time ``t``, and ``I`` is size of input units.
Note that this functions supports variable length sequences.
When sequneces has different lengths, sort sequences in descending
order by length, and transpose the sorted sequence.
:func:`~chainer.functions.transpose_sequence` transpose a list
of :func:`~chainer.Variable` holding sequence.
So ``xs`` needs to satisfy
``xs[t].shape[0] >= xs[t + 1].shape[0]``.
activation (str): Activation function name.
Please select ``tanh`` or ``relu``.
use_bi_direction (bool): If ``True``, this function uses
Bi-directional RNN.
Returns:
tuple: This functions returns a tuple concaining three elements,
``hy`` and ``ys``.
- ``hy`` is an updated hidden states whose shape is same as ``hx``.
- ``ys`` is a list of :class:`~chainer.Variable` . Each element
``ys[t]`` holds hidden states of the last layer corresponding
to an input ``xs[t]``. Its shape is ``(B_t, N)`` where ``B_t``
is mini-batch size for time ``t``, and ``N`` is size of hidden
units. Note that ``B_t`` is the same value as ``xs[t]``.
.. seealso::
:func:`chainer.functions.n_step_rnn`
:func:`chainer.functions.n_step_birnn`
""" # NOQA
argument.check_unexpected_kwargs(
kwargs, train='train argument is not supported anymore. '
'Use chainer.using_config',
use_cudnn='use_cudnn argument is not supported anymore. '
'Use chainer.using_config')
argument.assert_kwargs_empty(kwargs)
activation_list = ['tanh', 'relu']
if activation not in activation_list:
candidate = ','.join(activation_list)
raise ValueError('Invalid activation: "%s". Please select from [%s]'
% (activation, candidate))
xp = cuda.get_array_module(hx)
if xp is not numpy and chainer.should_use_cudnn('>=auto', 5000):
states = get_random_state().create_dropout_states(dropout_ratio)
# flatten all input variables
inputs = tuple(itertools.chain(
(hx, ),
itertools.chain.from_iterable(ws),
itertools.chain.from_iterable(bs),
xs))
if use_bi_direction:
# Bi-directional RNN
if activation == 'tanh':
rnn = NStepBiRNNTanh(n_layers, states)
elif activation == 'relu':
rnn = NStepBiRNNReLU(n_layers, states)
else:
# Uni-directional RNN
if activation == 'tanh':
rnn = NStepRNNTanh(n_layers, states)
elif activation == 'relu':
rnn = NStepRNNReLU(n_layers, states)
ret = rnn(*inputs)
hy, = ret[:1]
ys = ret[1:]
return hy, ys
else:
direction = 2 if use_bi_direction else 1
hx = split_axis.split_axis(hx, n_layers * direction, axis=0,
force_tuple=True)
hx = [reshape.reshape(h, h.shape[1:]) for h in hx]
xws = [_stack_weight([w[0]]) for w in ws]
hws = [_stack_weight([w[1]]) for w in ws]
xbs = [_stack_weight([b[0]]) for b in bs]
hbs = [_stack_weight([b[1]]) for b in bs]
xs_next = xs
hy = []
for layer in six.moves.range(n_layers):
def _one_directional_loop(di):
# di=0, forward RNN
# di=1, backward RNN
xs_list = xs_next if di == 0 else reversed(xs_next)
layer_idx = direction * layer + di
h = hx[layer_idx]
h_list = []
for x in xs_list:
batch = x.shape[0]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
else:
h_rest = None
if layer > 0:
x = dropout.dropout(x, ratio=dropout_ratio)
rnn_in = (linear.linear(x, xws[layer_idx],
xbs[layer_idx]) +
linear.linear(h, hws[layer_idx], hbs[layer_idx]))
if activation == 'tanh':
h_bar = tanh.tanh(rnn_in)
elif activation == 'relu':
h_bar = relu.relu(rnn_in)
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
else:
h = h_bar
h_list.append(h_bar)
return h, h_list
# Forward RNN
h, h_forward = _one_directional_loop(di=0)
hy.append(h)
if use_bi_direction:
# Backward RNN
h, h_backward = _one_directional_loop(di=1)
h_backward.reverse()
# Concat
xs_next = [concat.concat([hfi, hbi], axis=1) for (hfi, hbi) in
six.moves.zip(h_forward, h_backward)]
hy.append(h)
else:
# Uni-directional RNN
xs_next = h_forward
ys = xs_next
hy = stack.stack(hy)
return hy, tuple(ys)
def fixed_length_n_step_lstm(
n_layers,
dropout_ratio,
hx,
cx,
ws,
bs,
xs,
train=True,
):
xp = cuda.get_array_module(hx, hx.data)
if xp is not numpy and cuda.cudnn_enabled and _cudnn_version >= 5000:
states = get_random_state().create_dropout_states(dropout_ratio)
# flatten all input variables
inputs = tuple(
itertools.chain((hx, cx), itertools.chain.from_iterable(ws),
itertools.chain.from_iterable(bs), (xs, )))
rnn = FixedLengthNStepLSTMFunction(n_layers, states, train=train)
ret = rnn(*inputs)
hy, cy, ys = ret
_, batch_size, dim = hy.shape
ys_reshape = F.reshape(ys,
(-1, batch_size, dim)) # (length, batch, dim)
return hy, cy, ys_reshape
else:
hx = split_axis.split_axis(hx, n_layers, axis=0, force_tuple=True)
hx = [reshape.reshape(h, h.shape[1:]) for h in hx]
cx = split_axis.split_axis(cx, n_layers, axis=0, force_tuple=True)
cx = [reshape.reshape(c, c.shape[1:]) for c in cx]
xws = [_stack_weight([w[2], w[0], w[1], w[3]]) for w in ws]
hws = [_stack_weight([w[6], w[4], w[5], w[7]]) for w in ws]
xbs = [_stack_weight([b[2], b[0], b[1], b[3]]) for b in bs]
hbs = [_stack_weight([b[6], b[4], b[5], b[7]]) for b in bs]
ys = []
for x in xs:
batch = x.shape[0]
h_next = []
c_next = []
for layer in six.moves.range(n_layers):
h = hx[layer]
c = cx[layer]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
c, c_rest = split_axis.split_axis(c, [batch], axis=0)
else:
h_rest = None
x = dropout.dropout(x, ratio=dropout_ratio)
h = dropout.dropout(h, ratio=dropout_ratio)
lstm_in = linear.linear(x, xws[layer], xbs[layer]) + \
linear.linear(h, hws[layer], hbs[layer])
c_bar, h_bar = lstm.lstm(c, lstm_in)
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
c = concat.concat([c_bar, c_rest], axis=0)
else:
h = h_bar
c = c_bar
h_next.append(h)
c_next.append(c)
x = h_bar
hx = h_next
cx = c_next
ys.append(x)
hy = stack.stack(hx)
cy = stack.stack(cx)
#return hy, cy, tuple(ys)
ys_concat = F.concat(ys, axis=0)
ys_reshape = F.reshape(
ys_concat,
(-1, ys[0].shape[0], ys[0].shape[1])) # (length, batch, dim)
return hy, cy, ys_reshape
def n_step_lstm_base(n_layers, dropout_ratio, hx, cx, ws, bs, xs, train,
use_cudnn, use_bi_direction):
"""Base function for Stack LSTM/BiLSTM functions.
This function is used at :func:`chainer.functions.n_step_lstm` and
:func:`chainer.functions.n_step_bilstm`.
This function's behavior depends on following arguments,
``activation`` and ``use_bi_direction``.
Args:
n_layers(int): Number of layers.
dropout_ratio(float): Dropout ratio.
hx (chainer.Variable): Variable holding stacked hidden states.
Its shape is ``(S, B, N)`` where ``S`` is number of layers and is
equal to ``n_layers``, ``B`` is mini-batch size, and ``N`` is
dimention of hidden units.
cx (chainer.Variable): Variable holding stacked cell states.
It has the same shape as ``hx``.
ws (list of list of chainer.Variable): Weight matrices. ``ws[i]``
represents weights for i-th layer.
Each ``ws[i]`` is a list containing eight matrices.
``ws[i][j]`` is corresponding with ``W_j`` in the equation.
Only ``ws[0][j]`` where ``0 <= j < 4`` is ``(I, N)`` shape as they
are multiplied with input variables. All other matrices has
``(N, N)`` shape.
bs (list of list of chainer.Variable): Bias vectors. ``bs[i]``
represnents biases for i-th layer.
Each ``bs[i]`` is a list containing eight vectors.
``bs[i][j]`` is corresponding with ``b_j`` in the equation.
Shape of each matrix is ``(N,)`` where ``N`` is dimention of
hidden units.
xs (list of chainer.Variable): A list of :class:`~chainer.Variable`
holding input values. Each element ``xs[t]`` holds input value
for time ``t``. Its shape is ``(B_t, I)``, where ``B_t`` is
mini-batch size for time ``t``, and ``I`` is size of input units.
Note that this functions supports variable length sequences.
When sequneces has different lengths, sort sequences in descending
order by length, and transpose the sorted sequence.
:func:`~chainer.functions.transpose_sequence` transpose a list
of :func:`~chainer.Variable` holding sequence.
So ``xs`` needs to satisfy
``xs[t].shape[0] >= xs[t + 1].shape[0]``.
train (bool): If ``True``, this function executes dropout.
use_cudnn (bool): If ``True``, this function uses cuDNN if available.
use_bi_direction (bool): If ``True``, this function uses Bi-directional
LSTM.
Returns:
tuple: This functions returns a tuple concaining three elements,
``hy``, ``cy`` and ``ys``.
- ``hy`` is an updated hidden states whose shape is same as ``hx``.
- ``cy`` is an updated cell states whose shape is same as ``cx``.
- ``ys`` is a list of :class:`~chainer.Variable` . Each element
``ys[t]`` holds hidden states of the last layer corresponding
to an input ``xs[t]``. Its shape is ``(B_t, N)`` where ``B_t`` is
mini-batch size for time ``t``, and ``N`` is size of hidden
units. Note that ``B_t`` is the same value as ``xs[t]``.
.. seealso::
:func:`chainer.functions.n_step_lstm`
:func:`chainer.functions.n_step_bilstm`
"""
xp = cuda.get_array_module(hx, hx.data)
if use_cudnn and xp is not numpy and cuda.cudnn_enabled and \
_cudnn_version >= 5000:
states = get_random_state().create_dropout_states(dropout_ratio)
# flatten all input variables
inputs = tuple(
itertools.chain((hx, cx), itertools.chain.from_iterable(ws),
itertools.chain.from_iterable(bs), xs))
if use_bi_direction:
rnn = NStepBiLSTM(n_layers, states, train=train)
else:
rnn = NStepLSTM(n_layers, states, train=train)
ret = rnn(*inputs)
hy, cy = ret[:2]
ys = ret[2:]
return hy, cy, ys
else:
direction = 2 if use_bi_direction else 1
split_size = n_layers * direction
hx = split_axis.split_axis(hx, split_size, axis=0, force_tuple=True)
hx = [reshape.reshape(h, h.shape[1:]) for h in hx]
cx = split_axis.split_axis(cx, split_size, axis=0, force_tuple=True)
cx = [reshape.reshape(c, c.shape[1:]) for c in cx]
xws = [_stack_weight([w[2], w[0], w[1], w[3]]) for w in ws]
hws = [_stack_weight([w[6], w[4], w[5], w[7]]) for w in ws]
xbs = [_stack_weight([b[2], b[0], b[1], b[3]]) for b in bs]
hbs = [_stack_weight([b[6], b[4], b[5], b[7]]) for b in bs]
xs_next = xs
hy = []
cy = []
for layer in six.moves.range(n_layers):
def _one_directional_loop(di):
# di=0, forward LSTM
# di=1, backward LSTM
h_list = []
c_list = []
layer_idx = direction * layer + di
h = hx[layer_idx]
c = cx[layer_idx]
if di == 0:
xs_list = xs_next
else:
xs_list = reversed(xs_next)
for x in xs_list:
batch = x.shape[0]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
c, c_rest = split_axis.split_axis(c, [batch], axis=0)
else:
h_rest = None
c_rest = None
if layer != 0:
x = dropout.dropout(x,
ratio=dropout_ratio,
train=train)
lstm_in = linear.linear(x, xws[layer_idx],
xbs[layer_idx]) + \
linear.linear(h, hws[layer_idx], hbs[layer_idx])
c_bar, h_bar = lstm.lstm(c, lstm_in)
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
c = concat.concat([c_bar, c_rest], axis=0)
else:
h = h_bar
c = c_bar
h_list.append(h_bar)
c_list.append(c_bar)
return h, c, h_list, c_list
h, c, h_forward, c_forward = _one_directional_loop(di=0)
hy.append(h)
cy.append(c)
if use_bi_direction:
# BiLSTM
h, c, h_backward, c_backward = _one_directional_loop(di=1)
hy.append(h)
cy.append(c)
h_backward.reverse()
# concat
xs_next = [
concat.concat([hfi, hbi], axis=1)
for (hfi, hbi) in zip(h_forward, h_backward)
]
else:
# Uni-directional RNN
xs_next = h_forward
ys = xs_next
hy = stack.stack(hy)
cy = stack.stack(cy)
return hy, cy, tuple(ys)
def n_step_gru_base(n_layers, dropout_ratio, hx, ws, bs, xs,
use_bi_direction, **kwargs):
"""n_step_gru_base(n_layers, dropout_ratio, hx, ws, bs, xs, use_bi_direction)
Base function for Stack GRU/BiGRU functions.
This function is used at :func:`chainer.functions.n_step_bigru` and
:func:`chainer.functions.n_step_gru`.
This function's behavior depends on argument ``use_bi_direction``.
.. warning::
``train`` and ``use_cudnn`` arguments are not supported anymore since
v2.
Instead, use ``chainer.using_config('train', train)`` and
``chainer.using_config('use_cudnn', use_cudnn)`` respectively.
See :func:`chainer.using_config`.
Args:
n_layers(int): Number of layers.
dropout_ratio(float): Dropout ratio.
hx (chainer.Variable): Variable holding stacked hidden states.
Its shape is ``(S, B, N)`` where ``S`` is number of layers and is
equal to ``n_layers``, ``B`` is mini-batch size, and ``N`` is
dimension of hidden units. Because of bi-direction, the
first dimension length is ``2S``.
ws (list of list of chainer.Variable): Weight matrices. ``ws[i]``
represents weights for i-th layer.
Each ``ws[i]`` is a list containing six matrices.
``ws[i][j]`` is corresponding with ``W_j`` in the equation.
Only ``ws[0][j]`` where ``0 <= j < 3`` is ``(I, N)`` shape as they
are multiplied with input variables. All other matrices has
``(N, N)`` shape.
bs (list of list of chainer.Variable): Bias vectors. ``bs[i]``
represnents biases for i-th layer.
Each ``bs[i]`` is a list containing six vectors.
``bs[i][j]`` is corresponding with ``b_j`` in the equation.
Shape of each matrix is ``(N,)`` where ``N`` is dimension of
hidden units.
xs (list of chainer.Variable): A list of :class:`~chainer.Variable`
holding input values. Each element ``xs[t]`` holds input value
for time ``t``. Its shape is ``(B_t, I)``, where ``B_t`` is
mini-batch size for time ``t``, and ``I`` is size of input units.
Note that this functions supports variable length sequences.
When sequneces has different lengths, sort sequences in descending
order by length, and transpose the sorted sequence.
:func:`~chainer.functions.transpose_sequence` transpose a list
of :func:`~chainer.Variable` holding sequence.
So ``xs`` needs to satisfy
``xs[t].shape[0] >= xs[t + 1].shape[0]``.
activation (str): Activation function name.
Please select ``tanh`` or ``relu``.
use_bi_direction (bool): If ``True``, this function uses
Bi-direction GRU.
.. seealso::
:func:`chainer.functions.n_step_rnn`
:func:`chainer.functions.n_step_birnn`
""" # NOQA
argument.check_unexpected_kwargs(
kwargs, train='train argument is not supported anymore. '
'Use chainer.using_config',
use_cudnn='use_cudnn argument is not supported anymore. '
'Use chainer.using_config')
argument.assert_kwargs_empty(kwargs)
xp = cuda.get_array_module(hx, hx.data)
if xp is not numpy and chainer.should_use_cudnn('>=auto', 5000):
states = get_random_state().create_dropout_states(dropout_ratio)
# flatten all input variables
inputs = tuple(itertools.chain(
(hx, ),
itertools.chain.from_iterable(ws),
itertools.chain.from_iterable(bs),
xs))
if use_bi_direction:
rnn = NStepBiGRU(n_layers, states)
else:
rnn = NStepGRU(n_layers, states)
ret = rnn(*inputs)
hy, = ret[:1]
ys = ret[1:]
return hy, ys
else:
direction = 2 if use_bi_direction else 1
hx = split_axis.split_axis(hx, n_layers * direction, axis=0,
force_tuple=True)
hx = [reshape.reshape(h, h.shape[1:]) for h in hx]
xws = [concat.concat([w[0], w[1], w[2]], axis=0) for w in ws]
hws = [concat.concat([w[3], w[4], w[5]], axis=0) for w in ws]
xbs = [concat.concat([b[0], b[1], b[2]], axis=0) for b in bs]
hbs = [concat.concat([b[3], b[4], b[5]], axis=0) for b in bs]
xs_next = xs
hy = []
for layer in six.moves.range(n_layers):
def _one_directional_loop(di):
# di=0, forward GRU
# di=1, backward GRU
xs_list = xs_next if di == 0 else reversed(xs_next)
layer_idx = direction * layer + di
h = hx[layer_idx]
h_list = []
for x in xs_list:
batch = x.shape[0]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
else:
h_rest = None
if layer > 0:
x = dropout.dropout(x, ratio=dropout_ratio)
gru_x = linear.linear(x, xws[layer_idx], xbs[layer_idx])
gru_h = linear.linear(h, hws[layer_idx], hbs[layer_idx])
W_r_x, W_z_x, W_x = split_axis.split_axis(gru_x, 3, axis=1)
U_r_h, U_z_h, U_x = split_axis.split_axis(gru_h, 3, axis=1)
r = sigmoid.sigmoid(W_r_x + U_r_h)
z = sigmoid.sigmoid(W_z_x + U_z_h)
h_bar = tanh.tanh(W_x + r * U_x)
h_bar = (1 - z) * h_bar + z * h
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
else:
h = h_bar
h_list.append(h_bar)
return h, h_list
# Forward GRU
h, h_forward = _one_directional_loop(di=0)
hy.append(h)
if use_bi_direction:
# Backward GRU
h, h_backward = _one_directional_loop(di=1)
h_backward.reverse()
# Concat
xs_next = [concat.concat([hfi, hbi], axis=1) for (hfi, hbi) in
six.moves.zip(h_forward, h_backward)]
hy.append(h)
else:
# Uni-directional GRU
xs_next = h_forward
ys = xs_next
hy = stack.stack(hy)
return hy, tuple(ys)
def n_step_lstm(
n_layers, dropout_ratio, hx, cx, ws, bs, xs, train=True,
use_cudnn=True):
"""Stacked Long Short-Term Memory function for sequence inputs.
This function calculates stacked LSTM with sequences. This function gets
an initial hidden state :math:`h_0`, an initial cell state :math:`c_0`,
an input sequence :math:`x`, weight matrices :math:`W`, and bias vectors
:math:`b`.
This function calculates hidden states :math:`h_t` and :math:`c_t` for each
time :math:`t` from input :math:`x_t`.
.. math::
i_t &= \\sigma(W_0 x_t + W_4 h_{t-1} + b_0 + b_4) \\\\
f_t &= \\sigma(W_1 x_t + W_5 h_{t-1} + b_1 + b_5) \\\\
o_t &= \\sigma(W_2 x_t + W_6 h_{t-1} + b_2 + b_6) \\\\
a_t &= \\tanh(W_3 x_t + W_7 h_{t-1} + b_3 + b_7) \\\\
c_t &= f_t \\dot c_{t-1} + i_t \\dot a_t \\\\
h_t &= o_t \\dot \\tanh(c_t)
As the function accepts a sequence, it calculates :math:`h_t` for all
:math:`t` with one call. Eight weight matrices and eight bias vectors are
required for each layers. So, when :math:`S` layers exists, you need to
prepare :math:`8S` weigth matrices and :math:`8S` bias vectors.
If the number of layers ``n_layers`` is greather than :math:`1`, input
of ``k``-th layer is hidden state ``h_t`` of ``k-1``-th layer.
Note that all input variables except first layer may have different shape
from the first layer.
Args:
n_layers(int): Number of layers.
dropout_ratio(float): Dropout ratio.
hx (chainer.Variable): Variable holding stacked hidden states.
Its shape is ``(S, B, N)`` where ``S`` is number of layers and is
equal to ``n_layers``, ``B`` is mini-batch size, and ``N`` is
dimention of hidden units.
cx (chainer.Variable): Variable holding stacked cell states.
It has the same shape as ``hx``.
ws (list of list of chainer.Variable): Weight matrices. ``ws[i]``
represents weights for i-th layer.
Each ``ws[i]`` is a list containing eight matrices.
``ws[i][j]`` is corresponding with ``W_j`` in the equation.
Only ``ws[0][j]`` where ``0 <= j < 4`` is ``(I, N)`` shape as they
are multiplied with input variables. All other matrices has
``(N, N)`` shape.
bs (list of list of chainer.Variable): Bias vectors. ``bs[i]``
represnents biases for i-th layer.
Each ``bs[i]`` is a list containing eight vectors.
``bs[i][j]`` is corresponding with ``b_j`` in the equation.
Shape of each matrix is ``(N,)`` where ``N`` is dimention of
hidden units.
xs (list of chainer.Variable): A list of :class:`~chainer.Variable`
holding input values. Each element ``xs[t]`` holds input value
for time ``t``. Its shape is ``(B_t, I)``, where ``B_t`` is
mini-batch size for time ``t``, and ``I`` is size of input units.
Note that this functions supports variable length sequences.
When sequneces has different lengths, sort sequences in descending
order by length, and transpose the sorted sequence.
:func:`~chainer.functions.transpose_sequence` transpose a list
of :func:`~chainer.Variable` holding sequence.
So ``xs`` needs to satisfy
``xs[t].shape[0] >= xs[t + 1].shape[0]``.
train (bool): If ``True``, this function executes dropout.
use_cudnn (bool): If ``True``, this function uses cuDNN if available.
Returns:
tuple: This functions returns a tuple concaining three elements,
``hy``, ``cy`` and ``ys``.
- ``hy`` is an updated hidden states whose shape is same as ``hx``.
- ``cy`` is an updated cell states whose shape is same as ``cx``.
- ``ys`` is a list of :class:`~chainer.Variable` . Each element
``ys[t]`` holds hidden states of the last layer corresponding
to an input ``xs[t]``. Its shape is ``(B_t, N)`` where ``B_t`` is
mini-batch size for time ``t``, and ``N`` is size of hidden
units. Note that ``B_t`` is the same value as ``xs[t]``.
.. seealso::
:func:`chainer.functions.lstm`
"""
xp = cuda.get_array_module(hx, hx.data)
if use_cudnn and xp is not numpy and cuda.cudnn_enabled and \
_cudnn_version >= 5000:
states = get_random_state().create_dropout_states(dropout_ratio)
# flatten all input variables
inputs = tuple(itertools.chain(
(hx, cx),
itertools.chain.from_iterable(ws),
itertools.chain.from_iterable(bs),
xs))
rnn = NStepLSTM(n_layers, states, train=train)
ret = rnn(*inputs)
hy, cy = ret[:2]
ys = ret[2:]
return hy, cy, ys
else:
hx = split_axis.split_axis(hx, n_layers, axis=0, force_tuple=True)
hx = [reshape.reshape(h, h.shape[1:]) for h in hx]
cx = split_axis.split_axis(cx, n_layers, axis=0, force_tuple=True)
cx = [reshape.reshape(c, c.shape[1:]) for c in cx]
xws = [_stack_weight([w[2], w[0], w[1], w[3]]) for w in ws]
hws = [_stack_weight([w[6], w[4], w[5], w[7]]) for w in ws]
xbs = [_stack_weight([b[2], b[0], b[1], b[3]]) for b in bs]
hbs = [_stack_weight([b[6], b[4], b[5], b[7]]) for b in bs]
ys = []
for x in xs:
batch = x.shape[0]
h_next = []
c_next = []
for layer in six.moves.range(n_layers):
h = hx[layer]
c = cx[layer]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
c, c_rest = split_axis.split_axis(c, [batch], axis=0)
else:
h_rest = None
x = dropout.dropout(x, ratio=dropout_ratio, train=train)
h = dropout.dropout(h, ratio=dropout_ratio, train=train)
lstm_in = linear.linear(x, xws[layer], xbs[layer]) + \
linear.linear(h, hws[layer], hbs[layer])
c_bar, h_bar = lstm.lstm(c, lstm_in)
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
c = concat.concat([c_bar, c_rest], axis=0)
else:
h = h_bar
c = c_bar
h_next.append(h)
c_next.append(c)
x = h_bar
hx = h_next
cx = c_next
ys.append(x)
hy = stack.stack(hx)
cy = stack.stack(cx)
return hy, cy, tuple(ys)
def n_step_rnn_base(n_layers, dropout_ratio, hx, ws, bs, xs, activation,
use_bi_direction, **kwargs):
"""n_step_rnn_base(n_layers, dropout_ratio, hx, ws, bs, xs, activation, use_bi_direction)
Base function for Stack RNN/BiRNN functions.
This function is used at :func:`chainer.functions.n_step_birnn` and
:func:`chainer.functions.n_step_rnn`.
This function's behavior depends on following arguments,
``activation`` and ``use_bi_direction``.
.. warning::
``train`` and ``use_cudnn`` arguments are not supported anymore since
v2.
Instead, use ``chainer.using_config('train', train)`` and
``chainer.using_config('use_cudnn', use_cudnn)`` respectively.
See :func:`chainer.using_config`.
Args:
n_layers(int): Number of layers.
dropout_ratio(float): Dropout ratio.
hx (chainer.Variable): Variable holding stacked hidden states.
Its shape is ``(S, B, N)`` where ``S`` is number of layers and is
equal to ``n_layers``, ``B`` is mini-batch size, and ``N`` is
dimention of hidden units.
ws (list of list of chainer.Variable): Weight matrices. ``ws[i]``
represents weights for i-th layer.
Each ``ws[i]`` is a list containing two matrices.
``ws[i][j]`` is corresponding with ``W_j`` in the equation.
Only ``ws[0][j]`` where ``0 <= j < 1`` is ``(I, N)`` shape as they
are multiplied with input variables. All other matrices has
``(N, N)`` shape.
bs (list of list of chainer.Variable): Bias vectors. ``bs[i]``
represnents biases for i-th layer.
Each ``bs[i]`` is a list containing two vectors.
``bs[i][j]`` is corresponding with ``b_j`` in the equation.
Shape of each matrix is ``(N,)`` where ``N`` is dimention of
hidden units.
xs (list of chainer.Variable): A list of :class:`~chainer.Variable`
holding input values. Each element ``xs[t]`` holds input value
for time ``t``. Its shape is ``(B_t, I)``, where ``B_t`` is
mini-batch size for time ``t``, and ``I`` is size of input units.
Note that this functions supports variable length sequences.
When sequneces has different lengths, sort sequences in descending
order by length, and transpose the sorted sequence.
:func:`~chainer.functions.transpose_sequence` transpose a list
of :func:`~chainer.Variable` holding sequence.
So ``xs`` needs to satisfy
``xs[t].shape[0] >= xs[t + 1].shape[0]``.
activation (str): Activation function name.
Please select ``tanh`` or ``relu``.
use_bi_direction (bool): If ``True``, this function uses
Bi-directional RNN.
Returns:
tuple: This functions returns a tuple concaining three elements,
``hy`` and ``ys``.
- ``hy`` is an updated hidden states whose shape is same as ``hx``.
- ``ys`` is a list of :class:`~chainer.Variable` . Each element
``ys[t]`` holds hidden states of the last layer corresponding
to an input ``xs[t]``. Its shape is ``(B_t, N)`` where ``B_t``
is mini-batch size for time ``t``, and ``N`` is size of hidden
units. Note that ``B_t`` is the same value as ``xs[t]``.
.. seealso::
:func:`chainer.functions.n_step_rnn`
:func:`chainer.functions.n_step_birnn`
""" # NOQA
argument.check_unexpected_kwargs(
kwargs,
train='train argument is not supported anymore. '
'Use chainer.using_config',
use_cudnn='use_cudnn argument is not supported anymore. '
'Use chainer.using_config')
argument.assert_kwargs_empty(kwargs)
activation_list = ['tanh', 'relu']
if activation not in activation_list:
candidate = ','.join(activation_list)
raise ValueError('Invalid activation: "%s". Please select from [%s]' %
(activation, candidate))
xp = cuda.get_array_module(hx)
if xp is not numpy and chainer.should_use_cudnn('>=auto', 5000):
states = get_random_state().create_dropout_states(dropout_ratio)
# flatten all input variables
inputs = tuple(
itertools.chain((hx, ), itertools.chain.from_iterable(ws),
itertools.chain.from_iterable(bs), xs))
if use_bi_direction:
# Bi-directional RNN
if activation == 'tanh':
rnn = NStepBiRNNTanh(n_layers, states)
elif activation == 'relu':
rnn = NStepBiRNNReLU(n_layers, states)
else:
# Uni-directional RNN
if activation == 'tanh':
rnn = NStepRNNTanh(n_layers, states)
elif activation == 'relu':
rnn = NStepRNNReLU(n_layers, states)
ret = rnn(*inputs)
hy, = ret[:1]
ys = ret[1:]
return hy, ys
else:
direction = 2 if use_bi_direction else 1
hx = split_axis.split_axis(hx,
n_layers * direction,
axis=0,
force_tuple=True)
hx = [reshape.reshape(h, h.shape[1:]) for h in hx]
xws = [_stack_weight([w[0]]) for w in ws]
hws = [_stack_weight([w[1]]) for w in ws]
xbs = [_stack_weight([b[0]]) for b in bs]
hbs = [_stack_weight([b[1]]) for b in bs]
xs_next = xs
hy = []
for layer in six.moves.range(n_layers):
def _one_directional_loop(di):
# di=0, forward RNN
# di=1, backward RNN
xs_list = xs_next if di == 0 else reversed(xs_next)
layer_idx = direction * layer + di
h = hx[layer_idx]
h_list = []
for x in xs_list:
batch = x.shape[0]
if h.shape[0] > batch:
h, h_rest = split_axis.split_axis(h, [batch], axis=0)
else:
h_rest = None
if layer > 0:
x = dropout.dropout(x, ratio=dropout_ratio)
rnn_in = (
linear.linear(x, xws[layer_idx], xbs[layer_idx]) +
linear.linear(h, hws[layer_idx], hbs[layer_idx]))
if activation == 'tanh':
h_bar = tanh.tanh(rnn_in)
elif activation == 'relu':
h_bar = relu.relu(rnn_in)
if h_rest is not None:
h = concat.concat([h_bar, h_rest], axis=0)
else:
h = h_bar
h_list.append(h_bar)
return h, h_list
# Forward RNN
h, h_forward = _one_directional_loop(di=0)
hy.append(h)
if use_bi_direction:
# Backward RNN
h, h_backward = _one_directional_loop(di=1)
h_backward.reverse()
# Concat
xs_next = [
concat.concat([hfi, hbi], axis=1)
for (hfi, hbi) in six.moves.zip(h_forward, h_backward)
]
hy.append(h)
else:
# Uni-directional RNN
xs_next = h_forward
ys = xs_next
hy = stack.stack(hy)
return hy, tuple(ys)