论文标题
调度一台计算机的可变参数分析
Variable Parameter Analysis for Scheduling One Machine
论文作者
论文摘要
与固定参数分析(FPA)相反,在变量参数分析(VPA)中,目标问题参数的值不是固定的,而是取决于给定问题实例的结构,并且当输入的大小增加时倾向于具有良好的渐近行为。在将VPA应用于$ n $对象的棘手优化问题上时,可行解决方案集的枚举中的指数时间依赖性仅归因于可变参数$ν$,$ν<< n $。与FPA相反,VPA并不意味着对某些问题参数的任何限制,而是利用问题的有利性质,这允许减少解决方案空间的枚举成本。我们的主要技术贡献是一种可变的参数算法,用于强烈的$ \ mathsf {np} $ - 硬单基机器调度问题,以最大程度地减少作业迟到。目标变量参数$ν$是具有一些特定特征的作业数,即``新兴''。解决方案过程分为两个阶段。在第1阶段,包括$ n-ν$非出现工作在内的部分解决方案是在低度多项式时间内构建的。在第2阶段,考虑了$ν$新兴工作的$ν!$排列。他们每个人都被纳入第1阶段的部分时间表。
In contrast to the fixed parameter analysis (FPA), in the variable parameter analysis (VPA) the value of the target problem parameter is not fixed, it rather depends on the structure of a given problem instance and tends to have a favorable asymptotic behavior when the size of the input increases. While applying the VPA to an intractable optimization problem with $n$ objects, the exponential-time dependence in enumeration of the feasible solution set is attributed solely to the variable parameter $ν$, $ν<<n$. As opposed to the FPA, the VPA does not imply any restriction on some problem parameters, it rather takes an advantage of a favorable nature of the problem, which permits to reduce the cost of enumeration of the solution space. Our main technical contribution is a variable parameter algorithm for a strongly $\mathsf{NP}$-hard single-machine scheduling problem to minimize maximum job lateness. The target variable parameter $ν$ is the number of jobs with some specific characteristics, the ``emerging'' ones. The solution process is separated in two phases. At phase 1 a partial solution including $n-ν$ non-emerging jobs is constructed in a low degree polynomial time. At phase 2 less than $ν!$ permutations of the $ν$ emerging jobs are considered. Each of them are incorporated into the partial schedule of phase 1. Doe to the results of an earlier conducted experimental study, $ν/n$ varied from $1/4$ for small problem instances to $1/10$ for the largest tested problem instances, so that that the ratio becomes closer to 0 for large $n$s.