Just your regular densely-connected NN layer.

Dense层就是所谓的全连接神经网络层

# as first layer in a sequential model:
model = Sequential()
model.add(Dense(32, input_shape=(16,)))
# now the model will take as input arrays of shape (*, 16)
# and output arrays of shape (*, 32)

# after the first layer, you don't need to specify
# the size of the input anymore:
model.add(Dense(32))

第一层需要指定输入形状，以对接输入数据的形状，比如以(16,)对接(*,16)形状的数据。