Differences wrt to Instant-NSR

[nitinagarwal]

Hi Yuanchen, Great work on developing this. Could you point of the differences between this and Instant-NSR.

[bennyguo]

Hi! The main differences are:

• we adopt occupancy grid pruning via nerfacc which accelerates convergence
• multi-gpu and mixed precision support by pytorch-lightning
• better code structure for easy customization

[nitinagarwal]

Thanks!