def contrastive_loss_old(labels, dists):
label_first = labels[0:1, :]
other_labels = labels[1:, :]
labels_shifted = K.concatenate(
[labels, other_labels, label_first],
axis=0) # [ l1 ........ ln | l2 ... ln-1 ln ]
labels_orig = K.concatenate(
[labels, labels], axis=0) # [ l1 ........ ln | l1 ... ln-2 ln ]
zeros = K.zeros_like(labels_orig) # [ 0 ........ 0 | 0 ... 0 0 ]
h = K.cast(K.equal(labels_orig - labels_shifted, zeros),
dtype='float32') # [ 1 1 ...... 1 | 0 ... 1 0 ]
# h: ALL ONES | MOST ZEROS
# h[i] = 1 where labels_orig[i] == labels_shifted[i] (i-th image correlated with i+1-th image, i.e. same artwork)
# h[i] = 0 where labels_orig[i] != labels_shifted[i]
first_dist = dists[0:1]
other_dists = dists[1:]
shifted_dists = K.concatenate(
[dists, other_dists, first_dist],
axis=0) # [ d1 ........ dn | d1 ... dn-2 dn ]
# equation: Lcon = (1/2N) SUM[ h(i) d(i)^2 + (1-h(i)) max(1-d(i), 0)^2
Z = K.zeros_like(shifted_dists)
max_z_sd = K.max(K.stack([1 - shifted_dists, Z]), axis=0, keepdims=False)
#max_z_sd = K.sqrt(K.cast(K.shape(shifted_dists)[0], dtype='float32')) - shifted_dists
first_operand = h * K.square(shifted_dists)
second_operand = (1 - h) * K.square(max_z_sd)
tensor_sum = first_operand + second_operand
sum = K.sum(tensor_sum, axis=0) / K.cast(K.shape(shifted_dists)[0],
dtype='float32')
return K.mean(sum)
def spatial_attention(input_feature):
kernel_size = 7
if K.image_data_format() == "channels_first":
channel = input_feature._keras_shape[1]
cbam_feature = Permute((2, 3, 1))(input_feature)
else:
channel = input_feature._keras_shape[-1]
cbam_feature = input_feature
avg_pool = Lambda(lambda x: K.mean(x, axis=3, keepdims=True))(cbam_feature)
assert avg_pool._keras_shape[-1] == 1
max_pool = Lambda(lambda x: K.max(x, axis=3, keepdims=True))(cbam_feature)
assert max_pool._keras_shape[-1] == 1
concat = Concatenate(axis=3)([avg_pool, max_pool])
assert concat._keras_shape[-1] == 2
cbam_feature = Conv2D(filters=1,
kernel_size=kernel_size,
strides=1,
padding='same',
activation='sigmoid',
kernel_initializer='he_normal',
use_bias=False)(concat)
assert cbam_feature._keras_shape[-1] == 1
if K.image_data_format() == "channels_first":
cbam_feature = Permute((3, 1, 2))(cbam_feature)
return multiply([input_feature, cbam_feature])
def softmax_with_temp(args):
logits, temperature = args
repeat_num = K.shape(logits)[1]
temperature_repeated = RepeatVector(repeat_num)(temperature)
# shape == (batch_size, seq_len)
scaled_logits = logits / temperature_repeated
# shape == (batch_size, seq_len, vocab_size)
# for numerical stability (e.g. for low temperatures):
scaled_logits = scaled_logits - K.max(
scaled_logits, axis=2, keepdims=True)
# shape == (batch_size, seq_len, vocab_size)
transformed_probs = K.softmax(scaled_logits)
# shape == (batch_size, seq_len, vocab_size)
return transformed_probs
def lstm_attention(X_train, y_train, X_test, y_test, vocab_size):
X_train = sequence.pad_sequences(X_train, maxlen=MAX_LEN)
X_test = sequence.pad_sequences(X_test, maxlen=MAX_LEN)
print('X_train shape:', X_train.shape)
print('X_test shape:', X_test.shape)
print('Build model...')
model = Sequential()
# data
data = Input(shape=(MAX_LEN, ), dtype='int32', name='data')
# embedding
embedding = Embedding(vocab_size,
EMBED_SIZE,
input_length=MAX_LEN,
dropout=0.2)
data_embedding = embedding(data)
# dropout
dropout = Dropout(0.25)
data_dropout = dropout(data_embedding)
# rnn
rnn = RNN(HIDDEN_SIZE)
data_rnn = RNN(data_dropout)
#data_dropout = dropout(data_rnn)
# maxpooling
maxpool = Lambda(lambda x: K.max(x, axis=1, keepdims=False),
output_shape=lambda x: (x[0], x[2]))
data_pool = maxpool(data_dropout)
rnn = AttentionLSTM(HIDDEN_SIZE, data_pool)
def triplet_loss(y_true, y_pred):
return K.max(0, margin + y_pred)
def reed_hard_loss(y_true, y_pred):
'''Expects a binary class matrix instead of a vector of scalar classes.
'''
return -K.log(K.max(y_pred, axis=1, keepdims=True) + 1e-8)
from keras.layers import Dense, Embedding, LSTM, TimeDistributed, K, Lambda, Merge
f = pickle.load(open("words.pkl", 'rb'), encoding="bytes")
embeddings = f['embeddings']
f = pickle.load(open("data.pkl", 'rb'), encoding="bytes")
train1, train2, y = f['train1'][:, :40], f['train2'][:, :40], f['y']
q1 = Sequential()
q1.add(
Embedding(len(embeddings),
output_dim=100,
weights=[embeddings],
input_length=train1.shape[1],
trainable=False))
q1.add(TimeDistributed(Dense(100, activation='relu')))
q1.add(Lambda(lambda x: K.max(x, axis=1), output_shape=(100, )))
q2 = Sequential()
q2.add(
Embedding(len(embeddings),
output_dim=100,
weights=[embeddings],
input_length=train1.shape[1],
trainable=False))
q2.add(TimeDistributed(Dense(100, activation='relu')))
q2.add(Lambda(lambda x: K.sum(x, axis=1), output_shape=(100, )))
model = Sequential()
model.add(Merge([q1, q2], mode='concat'))
model.add(Dense(100, activation='relu'))
model.add(Dense(100, activation='relu'))
def sequence_mask(sequence):
return K.sign(K.max(K.abs(sequence), 2))
