In my opinion, some people might not be able to contribute to CuPy because of not having an NVIDIA GPU. But they might not know that we can build a development env on google colab(As I did here).

import os
from google.colab import drive
drive.mount('/content/drive')
os.chdir("/content/drive/My Drive/")

!git clone ht

The function mask_head_loss_pre takes gt_bboxes as the 4th positional argument, but the docstring does not contain what this argument is.
https://github.com/chainer/chainercv/blob/master/chainercv/links/model/fpn/mask_head.py#L171

Hi there,

Could you please consider adding documentation on reading the code, and which files to follow for what?

I would also consider adding function-level comments.

Great work!

I discovered in https://github.com/arogozhnikov/einops/blob/master/einops/einops.py#L199 that you also support ellipsis. Its an important feature so you may want to add it to the documentation.