def evaluate(data):
total, right, true_positives, possible_positives, predicted_positives = 0., 0., 0., 0., 0.
for x_true, y_true in data:
y_pred = model.predict(x_true).argmax(axis=1)
y_true = y_true[:, 0]
right += (y_true == y_pred).sum()
true_positives += K.sum(K.round(K.clip(y_true * y_pred, 0, 1))).numpy()
possible_positives += K.sum(K.round(K.clip(y_true, 0, 1))).numpy()
predicted_positives += K.sum(K.round(K.clip(y_pred, 0, 1))).numpy()
total += len(y_true)
accuracy = right / total
recall = true_positives / (possible_positives + K.epsilon())
precision = true_positives / (predicted_positives + K.epsilon())
f1_score = 2 * ((precision * recall) / (precision + recall + K.epsilon()))
return accuracy, recall, precision, f1_score
def new_update(x, new_x):
if is_one_of(x, params) and self._do_layer_adaptation(x):
dx = new_x - x
lr_t = K.clip(self.learning_rate, K.epsilon(), 1e10)
x_norm = tf.norm(x)
g_norm = tf.norm(dx / lr_t)
ratio = K.switch(
x_norm > 0.,
K.switch(g_norm > K.epsilon(), x_norm / g_norm, 1.),
1.)
new_x = x + dx * ratio
return old_update(x, new_x)
def new_update(x, new_x):
if x is var and self._do_layer_adaptation(x):
dx = new_x - x
lr_t = self._decayed_lr(x.dtype.base_dtype)
lr_t = K.clip(lr_t, K.epsilon(), K.infinity())
x_norm = tf.norm(x)
g_norm = tf.norm(dx / lr_t)
ratio = K.switch(
x_norm > 0.0,
K.switch(g_norm > 0.0, x_norm / g_norm, 1.0), 1.0)
new_x = x + dx * ratio
return old_update(x, new_x)
def compute_position_ids(self, inputs):
q, v = inputs
# 计算位置差
q_idxs = K.arange(0, K.shape(q)[1], dtype='int32')
q_idxs = K.expand_dims(q_idxs, 1)
v_idxs = K.arange(0, K.shape(v)[1], dtype='int32')
v_idxs = K.expand_dims(v_idxs, 0)
pos_ids = v_idxs - q_idxs
# 后处理操作
max_position = (self.input_dim - 1) // 2
pos_ids = K.clip(pos_ids, -max_position, max_position)
pos_ids = pos_ids + max_position
return pos_ids
def call(self, inputs, q_mask=False, v_mask=False, a_mask=False):
"""实现多头注意力
q_mask: 对输入的query序列的mask。
主要是将输出结果的padding部分置0。
v_mask: 对输入的value序列的mask。
主要是防止attention读取到padding信息。
a_mask: 对attention矩阵的mask。
不同的attention mask对应不同的应用。
"""
# 处理mask
inputs = inputs[:]
for i, mask in enumerate([q_mask, v_mask, a_mask]):
if not mask:
inputs.insert(3 + i, None)
q, k, v, q_mask, v_mask = inputs[:5]
if len(inputs) == 5:
a_mask = 'history_only'
elif len(inputs) == 6:
a_mask = inputs[-1]
else:
raise ValueError('wrong inputs for MultiHeadAttention.')
# 线性变换
qw = self.q_dense(q)
kw = self.k_dense(k)
vw = self.v_dense(v)
# 形状变换
qw = K.reshape(qw, (-1, K.shape(q)[1], self.heads, self.key_size))
kw = K.reshape(kw, (-1, K.shape(k)[1], self.heads, self.key_size))
vw = K.reshape(vw, (-1, K.shape(v)[1], self.heads, self.head_size))
# Attention
a = tf.einsum('bjhd,bkhd->bhjk', qw, kw)
# 相对位置编码
if self.max_relative_position is not None:
q_idxs = K.arange(0, K.shape(q)[1], dtype='int32')
q_idxs = K.expand_dims(q_idxs, 1)
v_idxs = K.arange(0, K.shape(v)[1], dtype='int32')
v_idxs = K.expand_dims(v_idxs, 0)
pos_ids = v_idxs - q_idxs
pos_ids = K.clip(pos_ids, -self.max_relative_position,
self.max_relative_position)
pos_ids = pos_ids + self.max_relative_position
pos_embeddings = K.gather(self.relative_embeddings, pos_ids)
a = a + tf.einsum('bjhd,jkd->bhjk', qw, pos_embeddings)
# Attention（续）
a = a / self.key_size**0.5
a = sequence_masking(a, v_mask, 1, -1)
if a_mask is not None:
if is_string(a_mask):
ones = K.ones_like(a[:1, :1])
a_mask = (ones - tf.linalg.band_part(ones, -1, 0)) * 1e12
a = a - a_mask
else:
a = a - (1 - a_mask) * 1e12
a = K.softmax(a)
# 完成输出
o = tf.einsum('bhjk,bkhd->bjhd', a, vw)
if self.max_relative_position is not None:
o = o + tf.einsum('bhjk,jkd->bjhd', a, pos_embeddings)
o = K.reshape(o, (-1, K.shape(o)[1], self.out_dim))
o = self.o_dense(o)
o = sequence_masking(o, q_mask, 0)
return o
def call(self, inputs, q_mask=None, v_mask=None, a_mask=None):
"""实现多头注意力
q_mask: 对输入的query序列的mask。
主要是将输出结果的padding部分置0。
v_mask: 对输入的value序列的mask。
主要是防止attention读取到padding信息。
a_mask: 对attention矩阵的mask。
不同的attention mask对应不同的应用。
"""
q, k, v = inputs[:3]
if a_mask:
if len(inputs) == 3:
a_mask = 'history_only'
else:
a_mask = inputs[3]
if q_mask is not None:
if not hasattr(self, 'q_mask_layer'):
self.q_mask_layer = search_layer(q, q_mask)
q_mask = self.q_mask_layer.output_mask
if v_mask is not None:
if not hasattr(self, 'v_mask_layer'):
self.v_mask_layer = search_layer(v, v_mask)
v_mask = self.v_mask_layer.output_mask
# Pooling
if self.pool_size > 1:
is_self_attention = (q is k is v)
q_in_len = K.shape(q)[1]
q = sequence_masking(q, q_mask, 0)
q = divisible_temporal_padding(q, self.pool_size)
q = pool1d(q, self.pool_size, self.pool_size, pool_mode='avg')
if is_self_attention:
k = v = q
else:
k = sequence_masking(k, v_mask, 0)
k = divisible_temporal_padding(k, self.pool_size)
k = pool1d(k, self.pool_size, self.pool_size, pool_mode='avg')
v = sequence_masking(v, v_mask, 0)
v = divisible_temporal_padding(v, self.pool_size)
v = pool1d(v, self.pool_size, self.pool_size, pool_mode='avg')
if v_mask is not None:
v_mask = v_mask[:, ::self.pool_size]
if a_mask is not None and not is_string(a_mask):
a_mask = a_mask[..., ::self.pool_size, ::self.pool_size]
# 线性变换
qw = self.q_dense(q)
kw = self.k_dense(k)
vw = self.v_dense(v)
# 形状变换
qw = K.reshape(qw, (-1, K.shape(q)[1], self.heads, self.key_size))
kw = K.reshape(kw, (-1, K.shape(k)[1], self.heads, self.key_size))
vw = K.reshape(vw, (-1, K.shape(v)[1], self.heads, self.head_size))
# Attention
a = tf.einsum('bjhd,bkhd->bhjk', qw, kw)
# 相对位置编码
if self.max_relative_position is not None:
q_idxs = K.arange(0, K.shape(q)[1], dtype='int32')
q_idxs = K.expand_dims(q_idxs, 1)
v_idxs = K.arange(0, K.shape(v)[1], dtype='int32')
v_idxs = K.expand_dims(v_idxs, 0)
pos_ids = v_idxs - q_idxs
pos_ids = K.clip(pos_ids, -self.max_relative_position,
self.max_relative_position)
pos_ids = pos_ids + self.max_relative_position
pos_embeddings = K.gather(self.relative_embeddings, pos_ids)
a = a + tf.einsum('bjhd,jkd->bhjk', qw, pos_embeddings)
# Attention（续）
a = a / self.key_size**0.5
a = sequence_masking(a, v_mask, 1, -1)
if a_mask is not None:
if is_string(a_mask):
ones = K.ones_like(a[:1, :1])
a_mask = (ones - tf.linalg.band_part(ones, -1, 0)) * 1e12
a = a - a_mask
else:
a = a - (1 - a_mask) * 1e12
a = K.softmax(a)
# 完成输出
o = tf.einsum('bhjk,bkhd->bjhd', a, vw)
if self.max_relative_position is not None:
o = o + tf.einsum('bhjk,jkd->bjhd', a, pos_embeddings)
o = K.reshape(o, (-1, K.shape(o)[1], self.out_dim))
o = self.o_dense(o)
# 恢复长度
if self.pool_size > 1:
o = K.repeat_elements(o, self.pool_size, 1)[:, :q_in_len]
# 返回结果
o = sequence_masking(o, q_mask, 0)
return o
