More robust install instructions (#2277)

Add cuda-toolkit install to readme/docs

docs/quickstart/installation.md

@@ -33,44 +33,47 @@ python -m pip install --upgrade pip
 
 (pytorch)=
 
-### pytorch
+### PyTorch
 
-::::{tab-set}
-:::{tab-item} Torch 2.0.1 with CUDA 11.8
-
-- To install 2.0.1 with CUDA 11.8:
-
-Note that if a pytorch version prior to 2.0.1 is installed,
+Note that if a PyTorch version prior to 2.0.1 is installed,
 the previous version of pytorch, functorch, and tiny-cuda-nn should be uninstalled.
 
 ```bash
 pip uninstall torch torchvision functorch tinycudann
 ```
 
-Install pytorch 2.0.1 with CUDA and [tiny-cuda-nn](https://github.com/NVlabs/tiny-cuda-nn)
+::::{tab-set}
+:::{tab-item} Torch 2.0.1 with CUDA 11.8
+
+Install PyTorch 2.0.1 with CUDA 11.8:
 
 ```bash
 pip install torch==2.0.1+cu118 torchvision==0.15.2+cu118 --extra-index-url https://download.pytorch.org/whl/cu118
 ```
 
+To build the necessary CUDA extensions, `cuda-toolkit` is also required. We
+recommend installing with conda:
+
+```bash
+conda install -c "nvidia/label/cuda-11.7.1" cuda-toolkit
+```
+
 :::
 :::{tab-item} Torch 2.0.1 with CUDA 11.7
 
-- To install 2.0.1 with CUDA 11.7:
-
-Note that if a pytorch version prior to 2.0.1 is installed,
-the previous version of pytorch, functorch, and tiny-cuda-nn should be uninstalled.
-
-```bash
-pip uninstall torch torchvision functorch tinycudann
-```
-
-Install pytorch 2.0.1 with CUDA and [tiny-cuda-nn](https://github.com/NVlabs/tiny-cuda-nn)
+Install PyTorch 2.0.1 with CUDA 11.7:
 
 ```bash
 pip install torch==2.0.1+cu117 torchvision==0.15.2+cu117 --extra-index-url https://download.pytorch.org/whl/cu117
 ```
 
+To build the necessary CUDA extensions, `cuda-toolkit` is also required. We
+recommend installing with conda:
+
+```bash
+conda install -c "nvidia/label/cuda-11.8.0" cuda-toolkit
+```
+
 :::
 ::::
 
@@ -258,7 +261,7 @@ While installing tiny-cuda, you run into: `The detected CUDA version mismatches
 
 **Solution**:
 
-Reinstall pytorch with the correct CUDA version.
+Reinstall PyTorch with the correct CUDA version.
 See [pytorch](pytorch) under Dependencies, above.
 
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