Hi everybody!

I am trying to write a C++ extension for Pytorch implementing a Convolutional LSTM. As I understood reading the documentation I have to write the backward() function myself. Starting from this tutorial I made the necessary modifications to the C++ code, but I have problems figuring out how to compute the backpropagation for the convolutional layers. I opened the C++ API documentation looking for a function that could compute the backprop for me and I found the function

```
at::_thnn_conv2d_backward
```

that judging by the name it should be what I was looking for, but the documentation is missing.

I was wandering: is it the right function to compute 2D convolution backprop? If not, which is the right function?