Install submodules diff-gaussian-rasterization and simple-knn

[ShaoxiongYao]

Hardware and Nvidia driver info:

+---------------------------------------------------------------------------------------+
| NVIDIA-SMI 535.154.05             Driver Version: 535.154.05   CUDA Version: 12.2     |
|-----------------------------------------+----------------------+----------------------+
| GPU  Name                 Persistence-M | Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp   Perf          Pwr:Usage/Cap |         Memory-Usage | GPU-Util  Compute M. |
|                                         |                      |               MIG M. |
|=========================================+======================+======================|
|   0  NVIDIA GeForce RTX 4090        Off | 00000000:01:00.0  On |                  Off |
|  0%   49C    P8              22W / 450W |   2357MiB / 24564MiB |     47%      Default |
|                                         |                      |                  N/A |
+-----------------------------------------+----------------------+----------------------+
                                                                                         
+---------------------------------------------------------------------------------------+
| Processes:                                                                            |
|  GPU   GI   CI        PID   Type   Process name                            GPU Memory |
|        ID   ID                                                             Usage      |
|=======================================================================================|
|    0   N/A  N/A      2109      G   /usr/lib/xorg/Xorg                         1297MiB |
|    0   N/A  N/A      2267      G   /usr/bin/gnome-shell                         92MiB |
|    0   N/A  N/A      2925      G   ...sion,SpareRendererForSitePerProcess      526MiB |
|    0   N/A  N/A     48454      G   ...yOnDemand --variations-seed-version      143MiB |
|    0   N/A  N/A     95811      G   ...,WinRetrieveSuggestionsOnlyOnDemand      161MiB |
|    0   N/A  N/A    558006      G   ...1692318,13779588870158544182,262144      113MiB |
+---------------------------------------------------------------------------------------+

NVCC info:

nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2021 NVIDIA Corporation
Built on Fri_Dec_17_18:16:03_PST_2021
Cuda compilation tools, release 11.6, V11.6.55
Build cuda_11.6.r11.6/compiler.30794723_0

Installed g++-10 info:

g++-10 (Ubuntu 10.5.0-1ubuntu1~22.04) 10.5.0
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Extra steps to install the submodules diff-gaussian-rasterization and simple-knn:

1. install the updated cudatoolkit (? may not be required): conda install -c conda-forge cudatoolkit-dev==11.6
2. install the g++-10: sudo apt install gcc-10 g++-10
3. update environment variables to use g++-10: export CC=/usr/bin/gcc-10, export CXX=/usr/bin/g++-10
4. cd to submodules directory and install: pip install .

And it works :)