assert coarse_occ_mask.sum() > 0, 'no foreground in coarse voxel' AssertionError: no foreground in coarse voxel

[xioatian1]

Thank you very much for open-sourcing this excellent work!
I tried to reproduce your work (coocc_multi_r50_256x704.py) using four 3090 GPUs, but encountered the issue shown in the image during the training process (I have already adjusted the learning rate)：assert coarse_occ_mask.sum() > 0, 'no foreground in coarse voxel' AssertionError: no foreground in coarse voxel.
This problem has been troubling me for a long time, could you please tell me how to solve it? Thank you so much!