The optimization problem is non-linear, convex and constrained. The optimal solution definitely exists and I'm not sure if it is unique or not. To be specific, the problem is called Alternating Current Optimal Power Flow problem. It is a non-convex problem which I have relaxed into a convex one.
First, when I say quality of solution, I mean that it is the measure of how close is the solution obtained to the optimal solution.
Is it possible to calculate that measure without knowing the optimal solution? If yes, how?
If no, what are the other definitions for 'Quality of the Solution' and how to measure quality in those cases?