Automatically detect the cuda availability and install corresponding torch nightly (#605)

Author: iseeyuan

README.md

@@ -56,20 +56,13 @@ python3 -m venv .venv
 source .venv/bin/activate
 ```
 
-After the virtual environment is activated, dependencies can be installed. torchchat depends on pytorch. By default, torch nightly with cpu will be installed.
+After the virtual environment is activated, dependencies can be installed.
 
 ```bash
 # install dependencies
 ./install_requirements.sh
 ```
 
-If CUDA GPUs are available, the argument of "cuda" can be added to accelerate the execution.
-
-```bash
-# install dependencies
-./install_requirements.sh cuda
-```
-
 Installations can be tested by
 
 ```bash

install_requirements.sh

@@ -44,13 +44,8 @@ NIGHTLY_VERSION=dev20240422
 # The pip repository that hosts nightly torch packages. cpu by default.
 TORCH_NIGHTLY_URL="https://download.pytorch.org/whl/nightly/cpu"
 
-# If cuda is available, use "cuda" argument to install the pytorch nightly
-# with cuda for faster execution on cuda GPUs.
-if [ "$1" == "cuda" ]
-then
-TORCH_NIGHTLY_URL="https://download.pytorch.org/whl/nightly/cu121"
-fi
-
+# If cuda is available, use the pytorch nightly with cuda for faster execution on cuda GPUs.
+test -f /usr/bin/nvidia-smi && TORCH_NIGHTLY_URL="https://download.pytorch.org/whl/nightly/cu121"
 
 # pip packages needed by exir.
 REQUIREMENTS_TO_INSTALL=(