Installation

Install PyCFX in user mode

PyCFX supports Python 3.10 through Python 3.14 on Windows and Linux.

Install PyCFX with all optional dependencies in user mode using this command:

pip install ansys-cfx-core

Install PyCFX in developer mode

The PyCFX source repository is available on GitHub. Clone the repository and set it up for local development with these commands:

git clone https://github.com/ansys/pycfx
cd pycfx
pip install -e .[doc,tests,style]
python codegen/allapigen.py  # Generate API files

Step-by-step instructions

Clone the repository

These commands clone the PyCFX repository from GitHub to your local machine and navigate to the repository directory:

git clone https://github.com/ansys/pycfx
cd pycfx

Install PyCFX and dependencies

This command installs PyCFX and all its dependencies:

pip install -e .[doc,tests,style]

The doc, tests, and style extras are necessary for building documentation, running unit tests, and checking code style before contributing.

Set up a virtual environment

Activate a virtual environment for PyCFX development:

python -m venv .venv
# On Windows
.\.venv\Scripts\activate
# On Linux
source .venv/bin/activate

Generate API classes

The full PyCFX package includes required API classes that are auto-generated instead of maintained under version control. This step requires an Ansys CFX installation.

Run this command to generate these files:

python codegen/allapigen.py     # Generate the API files silently

Use the -v or --verbose flag to display the paths of the generated API files:

python codegen/allapigen.py --verbose

Install pre-commit

The style checks use the pre-commit tool. To contribute changes to the PyCFX project, install pre-commit with this command:

python -m pip install pre-commit && pre-commit install

Run pre-commit on all modified files to ensure your changes conform to repository requirements:

pre-commit run

Build documentation

Build documentation using the rules provided in the Sphinx Makefile:

make -C doc/ html && your_browser_name doc/html/index.html

The recommended way to check documentation integrity is with this command:

tox -e doc && your_browser_name .tox/doc_out/index.html

Install Ansys CFX

To use PyCFX, you must have a licensed copy of Ansys CFX installed. PyCFX supports CFX 2025 R2 Service Pack 3 and later.

PyCFX uses an environment variable to locate your Ansys installation.

On Windows, the Ansys installer sets the environment variable. For example, the Ansys 2025 R2 installer sets the AWP_ROOT252 environment variable to point to C:\Program Files\ANSYS Inc\v252 if you accept the default installation location.

On Linux, the environment variable is not set automatically. Set it for the current user in the current shell session as follows:

export AWP_ROOT252=/usr/ansys_inc/v252

To make this variable persist between shell sessions, add this same export command to the user’s ~/.profile file.

For other ways to specify the CFX location for PyCFX, see How does PyCFX find the location to launch CFX? in Frequently asked questions.