Add changes to libtorch installation instructions.

modules/doc/content/getting_started/installation/install_libtorch.md

@@ -4,7 +4,11 @@ The way one enables LibTorch [!cite](paszke2019pytorch) capabilities in MOOSE de
 the operating system (Linux or Mac) and if we use HPC or just a local workstation.
 
 !alert! note
-Before we review the main approaches, it is important to emphasize that
+Before trying to install MOOSE with libtorch make sure to check out the
+[compatibility matrix](https://github.com/pytorch/pytorch/blob/main/RELEASE.md#release-compatibility-matrix)
+which will tell you if the required packages are compatible with the ones required by MOOSE.
+
+Furthermore, it is important to emphasize that
 linking MOOSE with libtorch on +Linux machines+ is not supported if the compiler stack has been built
 using a `libc` version below 2.27 (for `libtorch v 1.8+`)
 or 2.23 (for `libtorch v1.4-1.8`). Furthermore, we do not support `libtorch` versions below
@@ -16,22 +20,37 @@ ldd --version
 
 !alert-end!
 
-## Setting up the environment
+## Setup Environment
+
+For both Mac and Linux workstations, the user needs to follow the
+[Conda MOOSE Environment](installation/conda.md) instructions.
+
+## Install Libtorch
 
-For Mac workstations, the user needs to create a conda environment using the
-instructions [here](installation/conda.md). On Linux machines, however,
-we cannot use the conda packages due to the mismatch between `libc` versions.
-For this reason, given that the system `libc` version allows the linking between
-the two libraries, we need to install `PETSc` and `libMesh` manually. For instructions
-on the installation of these, see [installation/hpc_install_moose.md].
+The user can choose from three alternatives when it comes to installing `libtorch`:
 
-In situations when the `libc` version allows the linking but the compiler stack
-has been compiled with an older `libc` version (HPC machines potentially), we need to build the
-compiler from scratch. For instructions in this process, visit [installation/manual_installation_gcc.md]
+- +Install using conda:+
 
-## Installing Libtorch
+  For ARM and Intel Mac workstations the user can install libtorch using conda within the `moose` environment:
+
+  ```bash
+  conda install pytorch
+  ```
 
-The user can choose from two alternatives when it comes to installing `libtorch`:
+  This will provide the headers and libraries needed to use libtorch.
+
+  !alert! note
+
+  The same process works for Linux workstations if the user requires CPU support only.
+  To ensure this, add the `cpuonly` package to the installation line:
+
+  ```bash
+  conda install pytorch cpuonly -c pytorch
+  ```
+
+  For notes on the GPU support, visit the [notes below](install_libtorch.md#gpu-notes).
+
+  !alert-end!
 
 - +Install using the script provided in MOOSE:+
 
@@ -41,19 +60,27 @@ The user can choose from two alternatives when it comes to installing `libtorch`
   ./scripts/setup_libtorch.sh
   ```
 
-  which downloads `libtorch` from the official site and sets it up in the `framework\contrib`
-  directory. The script checks for operating system and `libc` version and throws errors
-  if the system is not suitable for the coupling.
+  which downloads `libtorch` from the official site and sets it up in the `framework/contrib`
+  directory.
+
+  !alert! note
+
+  The script checks for operating system and `libc` version (on Linux workstations)
+  and throws errors if the system is not suitable for the coupling. If there is a mismatch
+  between the detected `GLIBC` version and the one used to compile libtorch, the user needs
+  to install `libMesh` and `PETSc` manually with a compatible compiler.
+  !alert-end!
 
   !alert! note
+
   The desired version of libtorch can be set by the following argument:
 
   ```bash
   ./scripts/setup_libtorch.sh --version=1.8
   ```
 
   Note that we do not support `libtorch` below a version of 1.4. The default
-  version downloaded by the script is 1.10.
+  version downloaded by the script is 2.1.
 
   !alert-end!
 
@@ -62,9 +89,10 @@ The user can choose from two alternatives when it comes to installing `libtorch`
   [official website](https://github.com/pytorch/pytorch/blob/master/docs/libtorch.rst).
 
 
-## Configure and compile MOOSE with libtorch
+## Configure MOOSE
 
 To achieve this, first configure MOOSE with `libtorch` support (along with any other desired configure options)
+from within the `moose` folder:
 
 ```bash
 ./configure --with-libtorch
@@ -85,6 +113,29 @@ by the `setup_libtorch.sh` script.
 
 !alert-end!
 
+For conda-based installations the user can link to the conda-based libtorch libraries
+using the approach above (using a typical installation path within conda):
+
+
+```bash
+./configure --with-libtorch=${CONDA_PREFIX}/lib/python3.10/site-packages/torch
+```
+
+
+!alert! note
+
+The python version can be different depending on the distribution, so make sure you double-check if
+the directory you point to actually exists!
+An easy way to find if the library exists within the conda package is running the following command in the terminal:
+
+```bash
+find ${CONDA_PREFIX} -type d -name torch
+```
+
+!alert-end!
+
+## Build MOOSE
+
 The last step is to compile MOOSE with libtorch support:
 
 ```bash
@@ -100,3 +151,22 @@ The makefile of the [Stochastic Tools Module](stochastic_tools/stochastic_tools.
 serves as a good example on how to achieve this for applications.
 
 !alert-end!
+
+## GPU Support id=gpu-notes
+
+When using ARM Macs the conda-based installation supports both CPU and GPU devices.
+For GPU acceleration through Metal, users need to select MPS as a device when writing source code.
+
+!alert! warning
+
+GPU devices on Linux machines are not +officially+ supported yet.
+
+However, on Linux machines with existing CUDA and CUDA-enabled compiler support, one can
+compile MOOSE with a GPU-based Libtorch library without using the MOOSE conda environment.
+This means that the dependencies (PETSc, libMesh, WASP) need to be compiled
+manually. Following this, one can download an officially supported, CUDA-based
+precompiled library from the Libtorch website and supply that to the configure script
+before compiling MOOSE. If you have questions regarding this path,
+feel free to ask them on out Discussion forum!
+
+!alert-end!

scripts/setup_libtorch.sh

@@ -8,7 +8,7 @@
 #* Licensed under LGPL 2.1, please see LICENSE for details
 #* https://www.gnu.org/licenses/lgpl-2.1.html
 
-# For now, 2.1.0 is the default version of torchlib
+# For now, 2.1.0 is the default version of libtorch
 VERSION=2.1.0
 IGNORE_CERT=""
 
@@ -40,7 +40,7 @@ done
 
 # Show how to use the script
 if [[ -n "$HELP" ]]; then
-  echo "Usage: $0 [-h | --help | -k | --version=VERSION_NUMBER ]"
+  echo "Usage: $0 [-h | --help | -k | --version=VERSION_NUMBER | --cleanup ]"
   echo
   echo "-h | --help              Display this message and list of available setup options"
   echo "-k                       Ignore certifications while downloading packages with curl"
@@ -57,6 +57,12 @@ TORCH_DIR=$TORCH_DEST/libtorch
 # We need to do this because 1.12 is lower than 1.9 if parsed as a single number
 MAINVERSION=$(echo $VERSION | cut -d. -f1)
 SUBVERSION=$(echo $VERSION | cut -d. -f2)
+REVISION=$(echo $VERSION | cut -d. -f3)
+
+if [[ -z "${REVISION}" ]]; then
+  REVISION="0"
+  VERSION=$VERSION.0
+fi
 
 if (( $MAINVERSION < 1  || ( $MAINVERSION == 1  &&  $SUBVERSION < 4 ) )); then
   echo "The current implementation does not support libtorch versions below 1.4!"
@@ -68,25 +74,55 @@ if [ -d $TORCH_DIR ]; then
   rm -rf $TORCH_DIR
 fi
 
-# Checking the operating system
-UNAME_OUT="$(uname -s)"
-case "${UNAME_OUT}" in
+# Checking the operating system and architecture type
+UNAME_SYS="$(uname -s)"
+UNAME_ARCH="-$(uname -m)"
+case "${UNAME_SYS}" in
   Linux*)     OP_SYS=linux;;
   Darwin*)    OP_SYS=mac;;
 esac
 
+# We do some sanity checking on the version number. They started distributing
+# precompiled libraries for ARM machines afer version 2.2. Before that, it was x86 without the
+# tag
+if (( $OP_SYS == mac )); then
+  if (( $MAINVERSION < 2  || ( $MAINVERSION == 2 && $SUBVERSION < 2 ) )); then
+    if (( UNAME_ARCH == "-arm64" )); then
+      echo "Precompiled libraries below version 2.2 are not available for ARM architecture!"
+      exit 1
+    else
+      UNAME_ARCH=""
+    fi
+  fi
+else
+  UNAME_ARCH="" # We don't need this for linux machines
+fi
+
 # Checking if the available GLIBC version is sufficient for proper linkig. Only
 # causes issues on linux distributions. Considering that most Macs use the
 # moose compiler stack.
+function version_greater {
+  if { echo "$1"; echo "$2"; } | sort --version-sort --check=quiet; then
+    false
+  else
+    true
+  fi
+}
+function error_message {
+  echo "ERROR! The current version of GLIBC is not sufficient for proper linking!"
+  echo "Upgrade it to at least $1! Current version: $2"
+}
+
 if [[ $OP_SYS == linux ]]; then
   GLIBC_VERSION=`ldd --version | awk '/ldd/{print $NF}'`
-  if (( $SUBVERSION < 8 && $(echo "$GLIBC_VERSION < 2.23" | bc -l) )); then
-    echo "ERROR! The current version of GLIBC is not sufficient for proper linking!"
-    echo "Upgrade it to at least 2.23! Current version: $GLIBC_VERSION"
+  if not version_greater $VERSION 1.8 && (( $(echo "$GLIBC_VERSION < 2.23" | bc -l) )); then
+    error_message 2.23 $GLIBC_VERSION
+    exit 1
+  elif not version_greater $VERSION 2.1 && (( $(echo "$GLIBC_VERSION < 2.27" | bc -l) )); then
+    error_message 2.27 $GLIBC_VERSION
     exit 1
-  elif (( $SUBVERSION > 8 && $(echo "$GLIBC_VERSION < 2.27" | bc -l) )); then
-    echo "ERROR! The current version of GLIBC is not sufficient for proper linking!"
-    echo "Upgrade it to at least 2.27! Current version: $GLIBC_VERSION"
+  elif version_greater $VERSION 2.1 && (( $(echo "$GLIBC_VERSION < 2.29" | bc -l) )); then
+    error_message 2.29 $GLIBC_VERSION
     exit 1
   fi
 fi
@@ -97,7 +133,7 @@ FILENAME=""
 if [[ $OP_SYS == linux ]]; then
   FILENAME=libtorch-cxx11-abi-shared-with-deps-$VERSION%2B$TORCH_DISTRIBUTION.zip
 elif [[ $OP_SYS == mac ]]; then
-  FILENAME=libtorch-macos-$VERSION.zip
+  FILENAME=libtorch-macos$UNAME_ARCH-$VERSION.zip
 else
   echo "Unknown operating system! We only support Linux/Mac machines!"
   exit 1