In SNNS, TDNNs should be generated only with the tool BIGNET (Time Delay). This program automatically defines the necessary variables and link structures of TDNNs. The logical links are not depicted in the displays and can not be modified with the graphical editor. Any modifications of the units after the creation of the network may result in undesired behavior or even system failure!
After the creation of the net, the unit activation function Act_TD_Logistic, the update function TimeDelay_Order, and the learning function TimeDelayBackprop have to be assigned in the usual way.
NOTE: Only after the special time delay learning function has been assigned, will a save of the network also save the special logical links! A network saved beforehand will lack these links and be useless after a later load operation. Also using the and button will destroy the special time delay information unless the right update function ( TimeDelay_Order) has been chosen.
Patterns must fit the input layer. If the application requires variable pattern length, a tool to segment these patterns into fitting pieces has to be applied. Patterns may also be generated with the graphical user interface. In this case, it is the responsibility of the user to supply enough patterns with time shifted features for the same teaching output to allow a successful training.