how to implement backward propagation

Hi. I am new to triton and cuda. From my understanding, when we implement a customized pytorch operator using cuda, we need to define both forward and backward function, so that the gradients are propagated properly. However, in the triton document (e.g., how to implement vector addition, fused softmax ...), there seems nothing about backward function? Does that mean the backward function is automatically generated by triton? Thx!