In this tutorial we have seen how locally weighted learning and Vizier are used to help make decisions. All of the examples here involved a user operating the software. This is a great way to explore new data sets and learn about LWL. There are many applications, though, where it is necessary to incorporate the functionality of Vizier into other software. A controller running online in a factory is one example of an application where Vizier software is already being used. For this purpose the Vizier software package includes a library in C. Use of the library is documented in the header file for it, interface.h.