Эвристические алгоритмы для задачи целочисленного сбалансирования трехмерной матрицы с ограничениями второго рода

The problem of integer balancing of a three-dimensional matrix with constraints of second type is studied. The elements of the inner part (all three indices are greater than zero) of the three-dimensional matrix are summed in each direction and each section of the matrix; the total sum is also found. These sums are placed into the elements where one or more indices are equal to zero (according to the summing directions). The problem is to find an integer matrix of the same structure, which can be produced from the initial one by replacing the elements of the inner part with the largest previous or the smallest following integer. At the same time, variations of the sums of elements from those in the initial matrix should be less than 2 and the element with three zero indices should be produced with standard rules of rounding-off. Heuristic algorithms for this problem are suggested in the article: layering algorithm being got as generalization of a similar algorithm for the problem with constraints of first type and a new matrix algorithm. The last one consists of three parts: search for the base matrix, search for the maximal matrix and matrix correcting. Each of them is a cyclic change of the integer matrix using from 1 to 3 elements from the inner part. A modification of the matrix algorithm is suggested. The algorithm is directed to more uniform filling of the inner part of the integer matrix. Also, the complexity of all three algorithms is estimated in the article. The comparative analysis of matrix algorithms based on the results of computing experiments is adduced.Рассматривается задача целочисленного сбалансирования с ограничениями второго рода. В вещественной трехмерной матрице элементы внутренней части (все три индекса больше нуля) просуммированы по каждому направлению и сечению матрицы, а также найдена общая сумма. Данные суммы размещаются в элементах матрицы, у которых один или несколько индексов равны нулю (в соответствии с направлениями суммирования). Ищется целочисленная матрица той же структуры, получаемая из исходной заменой элементов внутренней части на округления до целого сверху или целого снизу. При этом суммирующие элементы должны отклоняться от исходных менее чем на 2, а элемент с тремя нулевыми индексами получается по обычным правилам округления.В статье разрабатываются эвристические алгоритмы решения задачи. Послойный алгоритм получается как обобщение соответствующего алгоритма для задачи с ограничениями первого рода. Предлагается новый матричный алгоритм, состоящий из трех частей: поиск базовой матрицы, поиск максимальной матрицы и коррекция матрицы. На всех шагах циклически проводятся изменения целочисленной матрицы, затрагивающие от 1 до 3 элементов внутренней части. Определяется модифицированный матричный алгоритм, направленный на более равномерное заполнение внутренней части целочисленной матрицы.Также в статье оценивается сложность всех трех алгоритмов и приводится сравнительный анализ матричных алгоритмов на основе результатов вычислительных экспериментов

Recent Advances in Graph Partitioning

We survey recent trends in practical algorithms for balanced graph partitioning together with applications and future research directions

SALBPGen - A systematic data generator for (simple) assembly line balancing

Assembly line balancing is a well-known and extensively researched decision problem which arises when assembly line production systems are designed and operated. A large variety of real-world problem variations and elaborate solution methods were developed and presented in the academic literature in the past 60 years. Nevertheless, computational experiments examining and comparing the performance of solution procedures were mostly based on very limited data sets unsystematically collected from the literature and from some real-world cases. In particular, the precedence graphs used as the basis of former tests are limited in number and characteristics. As a consequence, former performance analyses suffer from a lack of systematics and statistical evidence. In this article, we propose SALPBGen, a new instance generator for the simple assembly line balancing problem (SALBP) which can be applied to any other assembly line balancing problem, too. It is able to systematically create instances with very diverse structures under full control of the experiment's designer. In particular, based on our analysis of real-world problems from automotive and related industries, typical substructures of the precedence graph like chains, bottlenecks and modules can be generated and combined as required based on a detailed analysis of graph structures and structure measures like the order strength. We also present a collection of new challenging benchmark data sets which are suited for comprehensive statistical tests in comparative studies of solution methods for SALBP and generalized problems as well. Researchers are invited to participate in a challenge to solve these new problem instances.manufacturing, benchmark data set, assembly line balancing, precedence graph, structure analysis, complexity measures