# Precalculate the Domain and Range of Your Training Set¶

There’s one more piece of preparation to do before actually training the neural networks. For efficiency, quantities like the bounds on the physical input and output parameters are gathered from the training set just once, then saved in nn_config.toml. You can gather this information with the following command:

\$ neurosynchro lock-domain-range transformed .


Here transformed is the path to transformed training set and . is the path to the directory containing your nn_config.toml file — which, in the standard tutorial layout, is the current directory. This command will rewrite this file, embedding the needed quantities.