优化问题中的指标 Drop 和 Gap

The approximation ratio is computed on the total cost aggregated over the test set and is defined as the DROP \((1 − \frac{algorithm}{oracle})\) for maximization problems and the \(GAP (1 − \frac{oracle}{ algorithm})\) for minimization problems.

最大化问题 Maximization problem: Drop 越接近0越好。
最小化问题 Minimization problem：Gap 越接近0越好。