add software support m6 docs

docs/merlin6/software-support/ansys-fluent.md

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+# ANSYS - Fluent
+
+Is always recommended to check which parameters are available in Fluent and adapt the below example according to your needs.
+For that, run `fluent -help` for getting a list of options. However, as when running Fluent one must specify one of the
+following flags:
+
+* **2d**: This is a 2D solver with single point precision.
+* **3d**: This is a 3D solver with single point precision.
+* **2dpp**: This is a 2D solver with double point precision.
+* **3dpp**: This is a 3D solver with double point precision.
+
+## Running Fluent jobs
+
+### PModules
+
+Is strongly recommended the use of the latest ANSYS software available in PModules.
+
+```bash
+module use unstable
+module load Pmodules/1.1.6
+module use overlay_merlin
+module load ANSYS/2022R1
+```
+
+### Interactive: RSM from remote PSI Workstations
+
+Is possible to run Fluent through RSM from remote PSI (Linux or Windows)
+Workstation having a local installation of ANSYS Fluent and RSM client.  For
+that, please refer to the [ANSYS RSM](/merlin6/ansys-rsm.html) in the Merlin
+documentation for further information of how to setup a RSM client for
+submitting jobs to Merlin.
+
+### Non-interactive: sbatch
+
+Running jobs with `sbatch` is always the recommended method. This makes the use
+of the resources more efficient.  For running it as a job, one needs to run in
+no graphical mode (`-g` option).
+
+#### Serial example
+
+This example shows a very basic serial job.
+
+```bash
+#!/bin/bash
+#SBATCH --job-name=Fluent    # Job Name
+#SBATCH --partition=hourly   # Using 'daily' will grant higher priority than 'general'
+#SBATCH --time=0-01:00:00    # Time needed for running the job. Must match with 'partition' limits.
+#SBATCH --cpus-per-task=1    # Double if hyperthreading enabled
+#SBATCH --hint=nomultithread # Disable Hyperthreading
+#SBATCH --error=slurm-%j.err # Define your error file
+
+module use unstable
+module load ANSYS/2020R1-1
+
+# [Optional:BEGIN] Specify your license server if this is not 'lic-ansys.psi.ch'
+LICENSE_SERVER=<your_license_server>
+export ANSYSLMD_LICENSE_FILE=1055@$LICENSE_SERVER
+export ANSYSLI_SERVERS=2325@$LICENSE_SERVER
+# [Optional:END]
+
+JOURNAL_FILE=/data/user/caubet_m/Fluent/myjournal.in
+fluent 3ddp -g -i ${JOURNAL_FILE}
+```
+
+One can enable hypertheading by defining `--hint=multithread`, `--cpus-per-task=2` and `--ntasks-per-core=2`.
+However, this is in general not recommended, unless one can ensure that can be beneficial.
+
+#### MPI-based example
+
+An example for running Fluent using a Slurm batch script is the following:
+
+```bash
+#!/bin/bash
+#SBATCH --job-name=Fluent    # Job Name
+#SBATCH --partition=hourly   # Using 'daily' will grant higher priority than 'general'
+#SBATCH --time=0-01:00:00    # Time needed for running the job. Must match with 'partition' limits.
+#SBATCH --nodes=1            # Number of nodes
+#SBATCH --ntasks=44          # Number of tasks
+#SBATCH --cpus-per-task=1    # Double if hyperthreading enabled
+#SBATCH --ntasks-per-core=1  # Run one task per core
+#SBATCH --hint=nomultithread # Disable Hyperthreading
+#SBATCH --error=slurm-%j.err # Define a file for standard error messages
+##SBATCH --exclusive         # Uncomment if you want exclusive usage of the nodes
+
+module use unstable
+module load ANSYS/2020R1-1
+
+# [Optional:BEGIN] Specify your license server if this is not 'lic-ansys.psi.ch'
+LICENSE_SERVER=<your_license_server>
+export ANSYSLMD_LICENSE_FILE=1055@$LICENSE_SERVER
+export ANSYSLI_SERVERS=2325@$LICENSE_SERVER
+# [Optional:END]
+
+JOURNAL_FILE=/data/user/caubet_m/Fluent/myjournal.in
+fluent 3ddp -g -t ${SLURM_NTASKS} -i ${JOURNAL_FILE}
+```
+
+In the above example, one can increase the number of *nodes* and/or *ntasks* if needed. One can remove
+`--nodes` for running on multiple nodes, but may lead to communication overhead. In general, **no
+hyperthreading** is recommended for MPI based jobs. Also, one can combine it with `--exclusive` when necessary.
+
+## Interactive: salloc
+
+Running Fluent interactively is strongly not recommended and one should
+whenever possible use `sbatch`.  However, sometimes interactive runs are
+needed. For jobs requiring only few CPUs (in example, 2 CPUs) **and** for a
+short period of time, one can use the login nodes.  Otherwise, one must use the
+Slurm batch system using allocations:
+
+* For short jobs requiring more CPUs, one can use the Merlin shortest partitions (`hourly`).
+* For longer jobs, one can use longer partitions, however, interactive access
+  is not always possible (depending on the usage of the cluster).
+
+Please refer to the documentation **[Running Interactive
+Jobs](/merlin6/interactive-jobs.html)** for firther information about different
+ways for running interactive jobs in the Merlin6 cluster.
+
+### Requirements
+
+#### SSH Keys
+
+Running Fluent interactively requires the use of SSH Keys. This is the way of
+communication between the GUI and the different nodes. For doing that, one must
+have a **passphrase protected** SSH Key. If the user does not have SSH Keys yet
+(simply run **`ls $HOME/.ssh/`** to check whether **`id_rsa`** files exist or
+not). For deploying SSH Keys for running Fluent interactively, one should
+follow this documentation: **[Configuring SSH Keys](/merlin6/ssh-keys.html)**
+
+#### List of hosts
+
+For running Fluent using Slurm computing nodes, one needs to get the list of
+the reserved nodes. For getting that list, once you have the allocation, one
+can run the following command:
+
+```bash
+scontrol show hostname
+```
+
+This list must be included in the settings as the list of hosts where to run
+Fluent. Alternatively, one can give that list as parameter (`-cnf` option) when
+running `fluent`, as follows:
+
+??? example "Running Fluent with 'salloc'"
+    ```console
+    $ salloc --nodes=2 --ntasks=88 --hint=nomultithread --time=0-01:00:00 --partition=test $SHELL
+    salloc: Pending job allocation 135030174
+    salloc: job 135030174 queued and waiting for resources
+    salloc: job 135030174 has been allocated resources
+    salloc: Granted job allocation 135030174
+
+    $ module use unstable
+    $ module load ANSYS/2020R1-1
+    module load: unstable module has been loaded -- ANSYS/2020R1-1
+
+    $ fluent 3ddp -t$SLURM_NPROCS -cnf=$(scontrol show hostname | tr '\n' ',')
+
+    $ exit
+    exit
+    salloc: Relinquishing job allocation 135030174
+    salloc: Job allocation 135030174 has been revoked.
+    ```