Update data analysis section

docs/user/data_analysis/computing.md

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+(user.data_analysis.computing)=
+# Online data analysis
+
+We can access the online computing resources from the beamline consoles when logged in as the e-account.
+
+## Allocation of nodes
+
+Check available nodes and allocate one:
+
+```bash
+sinfo
+salloc -A csaxs -p csaxs -w [ra-c-110]
+ssh -Y [ra-c-110]
+```
+
+Or for a GPU node:
+
+```bash
+salloc -A csaxs -p gpu-csaxs --gpus=4 [-w ra-gpu-003] --mem=100G -n 8
+ssh -Y [ra-gpu-003]
+```
+
+(note that we need to ask them to explicitly use one of our GPU nodes there, and this needs a couple of days to set up)
+
+### Specifications of the computing nodes
+
+A few examples of the available nodes:
+
+| Node | CPU | Cores | Memory | GPUs | Partition |
+|---|---|---|---|---|---|
+| `ra-c-110` | Intel Xeon 6152 | 44 | 377 GB | — | `csaxs` |
+| `ra-gpu-003` | AMD EPYC 7452 | 64 | 1007 GB | 4x NVIDIA A100 (40 GB) | `gpu-csaxs` |
+| `ra-gpu-007` | Intel Xeon 6530 | 64 | 1007 GB | 4x NVIDIA L40S (46 GB)| `gpu-csaxs` |
+
+
+**The home directory is the p group.** To go to the raw directory we need to navigate there:
+
+```bash
+cd /sls/x12sa/data/[p22598]/raw
+```
+
+## Python tools
+
+### Python package installation
+
+Anaconda is no longer supported. Packages should now be installed directly using `pip`.
+
+For example, `pyFAI` can be installed as follows:
+
+```bash
+module load Python/3.11.11
+pip install "pyFAI[gui]"
+```
+
+To launch the `pyFAI` applications:
+
+```bash
+# Detector calibration
+python -m pyFAI.app.calib2
+
+# Batch integration
+python -m pyFAI.app.integrate
+```
+
+### Recommended: using a Python virtual environment
+
+For long-term maintainability and reproducibility, it is recommended to use a dedicated Python virtual environment.
+
+#### Create a virtual environment
+
+```bash
+cd /sls/x12sa/data/[p-group]/raw
+
+module load Python/3.11.11
+mkdir python-env
+cd python-env
+
+# Create a virtual environment named ".venv"
+python3 -m venv .venv
+
+# Activate the environment
+source .venv/bin/activate
+
+# Install required packages
+pip install "pyFAI[gui]"
+```
+
+#### Use an existing virtual environment
+
+```bash
+cd /sls/x12sa/data/[p-group]/raw/python-env
+source .venv/bin/activate
+```
+
+#### Troubleshooting
+
+If you encounter the following error when launching GUI applications (e.g. `pyFAI-calib2`):
+
+```text
+X11 connection rejected
+```
+
+reconnect to the analysis node with X11 forwarding enabled:
+
+```bash
+ssh -X [ra-c-110]
+```
+
+and then reactivate the virtual environment before launching the application.
+
+### Use Jupyter Notebook / Lab
+
+Create a virtual environment following the instructions above, then:
+
+```bash
+pip install jupyter
+```
+
+To run Jupyter Lab:
+
+```bash
+jupyter lab --port 6006 --ip $(hostname) --no-browser
+```
+## cSAXS matlab scripts
+
+To use the cSAXS matlab scripts we can go to the `cxs_software` package in the raw folder. 
+
+In base we can do:
+```bash
+source setup-environment.sh 
+```
+And then we can use Matlab interactively as usual.
+```bash
+matlab &
+```