我训练了一个单一模型,并希望使用函数式API将其与另一个Keras模型结合(后端为TensorFlow 1.4版本)。
我的第一个模型看起来像这样:
在训练完这个模型后,我使用Keras的model.save()方法保存了它。我也可以加载模型并重新训练它,没有任何问题。
现在我想使用这个模型的输出作为第二个模型的附加输入:
# 加载第一个模型old_model = keras.models.load_model(path_to_old_model)input_1 = Input(shape=(200,))input_2 = Input(shape=(200,))output_old_model = old_model(input_2)merge_layer = concatenate([input_1, output_old_model])dnn_layer = Dense(200, activation="relu")(merge_layer)dnn_layer = Dense(200, activation="relu")(dnn_layer)output = Dense(10, activation="sigmoid")(dnn_layer)new_model = keras.models.Model(inputs=[input_1, input_2], outputs=output)new_model.compile(loss="binary_crossentropy", optimizer="adam", metrics=["accuracy"]new_model.fit(inputs=[x1,x2], labels=labels, epochs=50, batch_size=32)
当我尝试这样做时,我得到了以下错误消息:
FailedPreconditionError (see above for traceback): Attempting to use uninitialized value dense_1/kernel [[Node: dense_1/kernel/read = Identity[T=DT_FLOAT, _class=["loc:@dense_1/kernel"], _device="/job:localhost/replica:0/task:0/device:GPU:0"](dense_1/kernel)]] [[Node: model_1_1/dense_3/BiasAdd/_79 = _Recv[client_terminated=false, recv_device="/job:localhost/replica:0/task:0/device:CPU:0", send_device="/job:localhost/replica:0/task:0/device:GPU:0", send_device_incarnation=1, tensor_name="edge_68_model_1_1/dense_3/BiasAdd", tensor_type=DT_FLOAT, _device="/job:localhost/replica:0/task:0/device:CPU:0"]()]]
回答:
我会按以下步骤来做这件事:
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定义一个函数,用于构建具有相同架构的干净模型:
def build_base(): input = Input(shape=(200,)) dnn = Dense(400, activation="relu")(input) dnn = Dense(400, activation="relu")(dnn) output = Dense(5, activation="softmax")(dnn) model = keras.models.Model(inputs=input, outputs=output) return input, output, model
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构建两个相同模型的副本:
input_1, output_1, model_1 = build_base()input_2, output_2, model_2 = build_base()
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在两个模型中设置权重:
model_1.set_weights(old_model.get_weights())model_2.set_weights(old_model.get_weights())
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现在完成剩余部分:
merge_layer = concatenate([input_1, output_2])dnn_layer = Dense(200, activation="relu")(merge_layer)dnn_layer = Dense(200, activation="relu")(dnn_layer)output = Dense(10, activation="sigmoid")(dnn_layer)new_model = keras.models.Model(inputs=[input_1, input_2], outputs=output)