论文标题
HESSIAN矩阵HESSIAN矩阵:分析表达,计算时间复杂性和稀疏性
The Hypervolume Indicator Hessian Matrix: Analytical Expression, Computational Time Complexity, and Sparsity
论文作者
论文摘要
可以将近似多目标优化问题的帕累托前端的问题重新归根结底,因为它找到了最大化超量指标的集合的问题。本文建立了映射的Hessian矩阵的分析表达,从$ d $ d $ d $二维的决策空间(或$ m $ dimensional Objective空间)中的$ n $点的集合到标量HyperVolume指示器值。为了定义Hessian矩阵,将输入集进行了矢量化,并且矩阵是通过从映射从矢量化集合到HyperVolume指标的映射的分析分化来得出的。 Hessian矩阵在二阶方法(例如Newton-Raphson优化方法)中起着至关重要的作用,并且可用于验证局部最佳集合。到目前为止,仅针对相对简单的双目标案例建立并分析了完整的分析表达。本文将得出任意维度的完整表达式($ M \ geq2 $目标函数)。对于实际上重要的三维情况,我们还提供了一种渐近有效的算法,并在$ O(n \ log n)$中具有时间复杂性,以精确计算Hessian Matrix的非零条目。我们为非零条目的数量建立了1200万美元的急剧限制。同样,对于一般的$ m $维情况,还建立了紧凑的递归分析表达式,并讨论了其算法实现。同样,对于一般情况,可以建立一些稀疏结果;这些结果暗示了递归表达。为了验证和说明分析得出的算法和结果,我们使用Python和Mathematica实现提供了一些数值示例。算法和测试数据的开源实现可作为本文补充。
The problem of approximating the Pareto front of a multiobjective optimization problem can be reformulated as the problem of finding a set that maximizes the hypervolume indicator. This paper establishes the analytical expression of the Hessian matrix of the mapping from a (fixed size) collection of $n$ points in the $d$-dimensional decision space (or $m$ dimensional objective space) to the scalar hypervolume indicator value. To define the Hessian matrix, the input set is vectorized, and the matrix is derived by analytical differentiation of the mapping from a vectorized set to the hypervolume indicator. The Hessian matrix plays a crucial role in second-order methods, such as the Newton-Raphson optimization method, and it can be used for the verification of local optimal sets. So far, the full analytical expression was only established and analyzed for the relatively simple bi-objective case. This paper will derive the full expression for arbitrary dimensions ($m\geq2$ objective functions). For the practically important three-dimensional case, we also provide an asymptotically efficient algorithm with time complexity in $O(n\log n)$ for the exact computation of the Hessian Matrix' non-zero entries. We establish a sharp bound of $12m-6$ for the number of non-zero entries. Also, for the general $m$-dimensional case, a compact recursive analytical expression is established, and its algorithmic implementation is discussed. Also, for the general case, some sparsity results can be established; these results are implied by the recursive expression. To validate and illustrate the analytically derived algorithms and results, we provide a few numerical examples using Python and Mathematica implementations. Open-source implementations of the algorithms and testing data are made available as a supplement to this paper.