by: Chris Cave
(Feyn version 3.0 or newer)
Purchasing a license
If you would like to use the
QLattice for commercial purposes then you need to contact sales on purchasing a license.
Once we have sent you a license key, create a new file called feyn.key or .feynkey and put that key in that file. That file should be located in your home or .config folder.
If this has worked then the next time you import feyn in a python environment you will be met with the following message:
"This Feyn package and QLattice is licensed to [your name], [your organistion]. By using this software you agree to the terms and conditions which can be found at