Adds lifted variables to turn a quadatic objective into a linear one; needed for conic solvers that only support linear objectives
cleans up raw pwl cost points in preparation for building a mathamatical model.
The key mathematical properties,
- the first and last points are strickly outside of the pmin-to-pmax range
- pmin and pmax occur in the first and last line segments.
Checks that all cost models are of the same type
Checks that all dcline cost models are of the same type
Checks that all generator cost models are of the same type
adds pdccost variables and constraints
adds pg_cost variables and constraints