File size: 8,494 Bytes
8fe2e46
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
import keras
from keras import layers
import tensorflow as tf

IMAGE_SIZE = (299, 299)
VOCAB_SIZE = 10000
SEQ_LENGTH = 25
EMBED_DIM = 512
FF_DIM = 512


image_augmentation = keras.Sequential(
    [
        keras.layers.RandomFlip("horizontal"),
        keras.layers.RandomRotation(0.2),
        keras.layers.RandomContrast(0.3),
    ]
)


@keras.saving.register_keras_serializable()
def get_cnn_model():
    base_model = keras.applications.efficientnet.EfficientNetB0(
        input_shape=(*IMAGE_SIZE, 3),
        include_top=False,
        weights="imagenet"
    )
    base_model.trainable = False
    base_model_out = base_model.output
    base_model_out = layers.Reshape(
        (-1, base_model_out.shape[-1]))(base_model_out)
    cnn_model = keras.models.Model(base_model.input, base_model_out)
    return cnn_model


@keras.saving.register_keras_serializable()
class TransformerEncoderBlock(layers.Layer):
    def __init__(self, embed_dim, dense_dim, num_heads, **kwargs):
        super().__init__(**kwargs)
        self.embed_dim = embed_dim
        self.dense_dim = dense_dim
        self.num_heads = num_heads
        self.attention_1 = layers.MultiHeadAttention(
            num_heads=num_heads, key_dim=embed_dim, dropout=0.0
        )
        self.layernorm_1 = layers.LayerNormalization()
        self.layernorm_2 = layers.LayerNormalization()
        self.dense_1 = layers.Dense(embed_dim, activation="relu")

    def get_config(self):
        base_config = super().get_config()
        config = {
            "embed_dim": self.embed_dim,
            "dense_dim": self.dense_dim,
            "num_heads": self.num_heads,
        }
        return {**base_config, **config}

    def call(self, inputs, training):
        inputs = self.layernorm_1(inputs)
        inputs = self.dense_1(inputs)

        attention_output_1 = self.attention_1(
            query=inputs,
            value=inputs,
            key=inputs,
            training=training,
        )
        out_1 = self.layernorm_2(inputs + attention_output_1)
        return out_1


@keras.saving.register_keras_serializable()
class PositionalEmbedding(layers.Layer):
    def __init__(self, sequence_length, vocab_size, embed_dim, **kwargs):
        super().__init__(**kwargs)
        self.token_embeddings = layers.Embedding(
            input_dim=vocab_size, output_dim=embed_dim, mask_zero=True
        )
        self.position_embeddings = layers.Embedding(
            input_dim=sequence_length, output_dim=embed_dim
        )
        self.sequence_length = sequence_length
        self.vocab_size = vocab_size
        self.embed_dim = embed_dim

        self.add = layers.Add()

    def get_config(self):
        base_config = super().get_config()
        config = {
            "sequence_length": self.sequence_length,
            "vocab_size": self.vocab_size,
            "embed_dim": self.embed_dim,
        }
        return {**base_config, **config}

    def call(self, seq):
        seq = self.token_embeddings(seq)

        x = tf.range(tf.shape(seq)[1])
        x = x[tf.newaxis, :]
        x = self.position_embeddings(x)

        return self.add([seq, x])


@keras.saving.register_keras_serializable()
class TransformerDecoderBlock(layers.Layer):
    def __init__(self, embed_dim, ff_dim, num_heads, **kwargs):
        super().__init__(**kwargs)
        self.embed_dim = embed_dim
        self.ff_dim = ff_dim
        self.num_heads = num_heads
        self.attention_1 = layers.MultiHeadAttention(
            num_heads=num_heads, key_dim=embed_dim, dropout=0.1
        )
        self.attention_2 = layers.MultiHeadAttention(
            num_heads=num_heads, key_dim=embed_dim, dropout=0.1
        )
        self.ffn_layer_1 = layers.Dense(ff_dim, activation="relu")
        self.ffn_layer_2 = layers.Dense(embed_dim)

        self.layernorm_1 = layers.LayerNormalization()
        self.layernorm_2 = layers.LayerNormalization()
        self.layernorm_3 = layers.LayerNormalization()

        self.embedding = PositionalEmbedding(
            embed_dim=EMBED_DIM,
            sequence_length=SEQ_LENGTH,
            vocab_size=VOCAB_SIZE,
        )
        self.out = layers.Dense(VOCAB_SIZE, activation="softmax")

        self.dropout_1 = layers.Dropout(0.3)
        self.dropout_2 = layers.Dropout(0.5)
        self.supports_masking = True

    def get_config(self):
        base_config = super().get_config()
        config = {
            "embed_dim": self.embed_dim,
            "ff_dim": self.ff_dim,
            "num_heads": self.num_heads,

        }
        return {**base_config, **config}

    def call(self, inputs, encoder_outputs, training, mask=None):
        inputs = self.embedding(inputs)

        attention_output_1 = self.attention_1(
            query=inputs,
            value=inputs,
            key=inputs,
            training=training,
            use_causal_mask=True
        )
        out_1 = self.layernorm_1(inputs + attention_output_1)

        attention_output_2 = self.attention_2(
            query=out_1,
            value=encoder_outputs,
            key=encoder_outputs,
            training=training,
        )
        out_2 = self.layernorm_2(out_1 + attention_output_2)

        ffn_out = self.ffn_layer_1(out_2)
        ffn_out = self.dropout_1(ffn_out, training=training)
        ffn_out = self.ffn_layer_2(ffn_out)

        ffn_out = self.layernorm_3(ffn_out + out_2, training=training)
        ffn_out = self.dropout_2(ffn_out, training=training)
        preds = self.out(ffn_out)
        return preds


@keras.saving.register_keras_serializable()
class ImageCaptioningModel(keras.Model):
    def __init__(

        self,

        cnn_model,

        encoder,

        decoder,

        image_aug=None,

        **kwargs

    ):
        super().__init__(**kwargs)
        self.cnn_model = cnn_model
        self.encoder = encoder
        self.decoder = decoder
        self.image_aug = image_aug

    def get_config(self):
        base_config = super().get_config()
        config = {
            "cnn_model": self.cnn_model,
            "encoder": self.encoder,
            "decoder": self.decoder,
            "image_aug": self.image_aug,
        }
        return {**base_config, **config}

    @classmethod
    def from_config(cls, config):
        # Note that you can also use [`keras.saving.deserialize_keras_object`](/api/models/model_saving_apis/serialization_utils#deserializekerasobject-function) here
        config["cnn_model"] = keras.saving.deserialize_keras_object(
            config["cnn_model"])
        config["encoder"] = keras.saving.deserialize_keras_object(
            config["encoder"])
        config["decoder"] = keras.saving.deserialize_keras_object(
            config["decoder"])
        config["image_aug"] = keras.saving.deserialize_keras_object(
            config["image_aug"])

    # Instantiate the ImageCaptioningModel with the remaining configuration
        return cls(**config)

    def call(self, inputs, training):
        img, caption = inputs
        if self.image_aug:
            img = self.image_aug(img)
        img_embed = self.cnn_model(img)
        encoder_out = self.encoder(img_embed, training=training)
        pred = self.decoder(caption, encoder_out, training=training)
        return pred

@keras.saving.register_keras_serializable()
class LRSchedule(keras.optimizers.schedules.LearningRateSchedule):
    def __init__(self, post_warmup_learning_rate, warmup_steps, **kwargs):
        super().__init__(**kwargs)
        self.post_warmup_learning_rate = post_warmup_learning_rate
        self.warmup_steps = warmup_steps

    def get_config(self):
        config = {
            "post_warmup_learning_rate": self.post_warmup_learning_rate,
            "warmup_steps": self.warmup_steps,
        }
        return config

    def __call__(self, step):
        global_step = tf.cast(step, tf.float32)
        warmup_steps = tf.cast(self.warmup_steps, tf.float32)
        warmup_progress = global_step / warmup_steps
        warmup_learning_rate = self.post_warmup_learning_rate * warmup_progress
        return tf.cond(
            global_step < warmup_steps,
            lambda: warmup_learning_rate,
            lambda: self.post_warmup_learning_rate,
        )