module CooCoo::CostFunctions

CostFunctions are used with a {Trainer} to determine how close a {Network} is coming to its target. CostFunctions are functions of two variables.

To get a cost function instance use the included {#from_name}. Then you can #call or #derivative any cost function.

To create a new cost function that can be used with a {Trainer}, you must call {CostFunctions.register} and implement the #call and #derivative class methods.