Concatenated ReLU

[dmm]

Definition 2.1 (page 3) of "Understanding and Improving Convolutional Neural Networks via Concatenated Rectified Linear Units" paper:

https://arxiv.org/abs/1603.05201

"crelu" is one of the built-in activation functions in TensorFlow:

https://www.tensorflow.org/api_docs/python/nn/activation_functions_