我创建了一个dataset有 27 列的。我创建了一个Autoencoder用于异常检测的目的，如下所示：
input_layer = Input(shape=(27,))
x = layers.Dense(20,activation='relu')(input_layer)
x = layers.Dense(14,activation='relu')(x)
x = layers.Dense(8, activation='relu')(x)
x = layers.Dense(14, activation='relu')(x)
x = layers.Dense(20,activation='relu')(x)
output = layers.Dense(27,activation='relu')(x)
AE = keras.models.Model(inputs=input_layer, outputs=output)
optimizer = keras.optimizers.Adam()
loss_fn = keras.losses.MeanSquaredError
iterator = iter(train_dataset)
a = iterator.get_next()
out = AE(a,training=True)
loss_value = loss_fn(a, out)
为什么会出现以下错误？
TypeError: Cannot convert 'auto' to EagerTensor of dtype float