🧑‍💻 VirtualEnv

What is a virtual environment?

Most software depends on other software to work. This software usually needs to be there in a very specific version, and may conflict with other programs that need other versions of the same program. To solve this, virtual environments have been invented. They are a single folder containing all the dependencies your program needs.

Where will OmniOpt2 install its dependencies to?

By default, OmniOpt2 tries to install the dependencies in a folder in your home folder, so that you only need to install OmniOpt2 once, and all other installations can access this virtualenv.
The default folder will be created like this:

.omniax_$(uname -m)_$(python3 --version | sed -e 's# #_#g')$_cluster

while uname -m yields to your CPU architecture (usually x86_64 ), python --version | sed -e 's# #_#g' will yield to your python version (e.g. 3.11.2 ), and $_cluster contains the cluster name, taken from the environment variable CLUSTERHOST .

How to install further modules manually

Sometimes you need to install more modules, ie. when you want to export to a certain database like Oracle or PostGRES. You can do that by first activating that virtualenv:

source ~/.omniax_x86_64_Python_3.11.2/bin/activate

and then installing modules with pip install ... .
Make sure you are running the same python-Version. That means, if you do it on a System with Lmod or similiar systems, module load ... the proper python-version and modules first.
On the capella partition of the TU Dresden HPC System, this would be:

ml release/24.04 GCCcore/12.3.0 Python/3.11.3 Tkinter/3.11.3 PostgreSQL/16.1

On the ML-Power9-Partition:

ml release/24.04 GCCcore/12.3.0 Python/3.11.3 Tkinter/3.11.3 PostgreSQL/16.1 zlib/1.2.12 GCC/12.2.0 OpenBLAS/0.3.21

On all others:

ml release/23.04 GCCcore/12.2.0 Python/3.10.8 GCCcore/11.3.0 Tkinter/3.10.4 PostgreSQL/14.4

Change the directory the virtual environment will be installed to

If you cannot write in your home, for example, because it is too full, you can set the path where the virtual environment will be installed and used to. Simply set the variable:

export root_venv_dir=/path/where/it/should/be/installed/to

You need to do this every time before you start OmniOpt2 as well, since without that shell variable (that has to be exported!) it will try to do it from your home again.