A functional variable is a variable whose value is calculated by a function. It is one of the three variable types in Rave, the others being:
Function variables are always created after an initial data set (of independent variables) has been loaded. They are created by performing one of the following two actions:
- Loading or creating a function from the Model Tab
- Loading metadata stored in a .rvm file
Currently Rave treats all functional variables as being continuous. Consequently, functional variables are limited to numerical values. You cannot load functions whose outputs are strings. This may change in the future.
Unlike independent variables, for which you can specify allowable values/ranges using the Manage Analyses GUI, you cannot control the ranges of functional variables. Instead, Rave automatically manages the ranges of functional variables to encompass the min/max limits that Rave has ever observed for each variable.
Rave initially sets the min/max value of the functional variable according to the min/max values that appear in the data set. If in the process of some data generating process, for example interacting with a continuous visualization or running an optimizer, Rave evaluates the function and finds a new value that is outside the current min/max range, it will update the range to reflect the newly found limits.