我希望将两个keras层合并，使得合并的层具有两个层之间的差异。例如，如果layer1输出为[0,1,2]，而layer2输出为[1,2,3]，则合并后的层应该是[-1，-1，-1]。我尝试使用以下代码：
from keras.layers import Input, merge
from keras.models import Model
import numpy as np
input_a = np.reshape([1, 2, 3], (1, 1, 3))
input_b = np.reshape([4, 5, 6], (1, 1, 3))
a = Input(shape=(1, 3))
b = Input(shape=(1, 3))
diff = merge([a, b], mode=lambda x, y: x - y)
diff_model = Model(input=[a, b], output=diff)
print(diff_model.predict([input_a, input_b]))
导致以下错误：
File "/usr/local/lib/python2.7/dist-packages/keras/engine/topology.py", line 1464, in merge │ self.add_inbound_node(layers, node_indices, tensor_indices)
name=name) │ File "/usr/local/lib/python2.7/dist-packages/keras/engine/topolog
File "/usr/local/lib/python2.7/dist-packages/keras/engine/topology.py", line 1123, in __init__ │y.py", line 543, in add_inbound_node
self.add_inbound_node(layers, node_indices, tensor_indices) │ Node.create_node(self, inbound_layers, node_indices, tensor_ind
File "/usr/local/lib/python2.7/dist-packages/keras/engine/topology.py", line 543, in add_inbound_node │ices)
Node.create_node(self, inbound_layers, node_indices, tensor_indices) │ File "/usr/local/lib/python2.7/dist-packages/keras/engine/topolog
File "/usr/local/lib/python2.7/dist-packages/keras/engine/topology.py", line 153, in create_node │y.py", line 155, in create_node
output_tensors = to_list(outbound_layer.call(input_tensors, mask=input_masks)) │ output_shapes = to_list(outbound_layer.get_output_shape_for(inp
File "/usr/local/lib/python2.7/dist-packages/keras/engine/topology.py", line 1200, in call │ut_shapes))
return self.mode(inputs, **arguments) │ File "/usr/local/lib/python2.7/dist-packages/keras/engine/topolog
TypeError: <lambda>() takes exactly 2 arguments (1 given)
我该如何执行合并操作？