Fujitsu Corporation

Akio Shinagawa

Kyohei Tamai

Fumiyoshi Sasagawa

Hiroyuki Okada

Yuko Abe

Hitoshi Ohno

Toshihiro Nishimura

Akira Hattori

Hiroyasu Itoh

Hiromu Hayashi

Nobue Adachi

Hajime Ohi

Ayumi Nakabayashi

Kazumi Takada

Tsuyoshi Shinogi

A computer determines to which of a plurality of levels each of a plurality of road types for which a path search is performed corresponds, according to a distance between a departure point and a destination point. Next, the computer performs a first path search for the road type associated with a first level from the departure point to the destination point, and a second path search for the road type associated with the first level from the destination point to the departure point. Then, the computer performs a third path search for the road type associated with a second level according to a point obtained in the first path search and a point obtained in the second path search, and generates path information according to a result of the first path search, the second path search, and the third path search.

Path searching method and path search device

A computer performs a path search from a first node to a second node by using nodes and links connecting two nodes and to which a cost is set. A first search method is used to search for one node from among nodes to be searched which are adjacent to the searched-for node and have not yet been searched for. Then, the distance between the searched-for node and the second node is recorded, and the searched-for node is recorded as an already-searched-for node. Next, the first search method is changed to a second search method in which a number of nodes to be searched is prevented from increasing according to distances between the second node and two or more searched-for nodes obtained as a result of performing searching and recording plural times. Then, path information is generated according to a node searched for by the second search method.

A computer performs a path search from a departure point to a destination point and a path search from the destination point to the departure point while changing a target from a road type at a level other than the highest level to a road type at a higher level, according to a first grouping of a plurality of road types, and performs a path search for the road type at the highest level in a first process. Next, the computer performs similar path searches in an area to be searched based on a result of the first process, according to a second grouping in which a greater number of road types is classified as the highest level in a second process. Then, the computer generates path information according to a result of the second process.

A uniform-density layout problem requires an optimal layout of multiple elements in a predetermined region under a set of conditions including a density-uniformization condition. The method determines an optimal solution to the problem and comprises the steps of: (a) obtaining an initial layout of the multiple elements in the predetermined region; (b) generating a linear combination of a first objective function, which represents the remaining conditions other than the density-uniformalization condition, and a second objective function, which represents the density-uniformalization condition, as a third objective function, which is assumed to represent the set of conditions of the problem; and (c) optimizing the third objective function by executing an iterative-improvement algorithm on the third objective function using the initial layout as an initial solution. The invention is especially useful to determine a layout of multiple circuit elements in designing LSI circuits and the like.

Method of and apparatus for determining an optimal solution to a uniform-density layout problem, and medium on which a program for determining the solution is stored

The invention provides an arrangement optimization problem processing apparatus for arranging a plurality of nodes in an optimum condition in a two- or more-dimensional space, by which an optimum arrangement of a plurality of nodes can be determined at a high speed even where a node arrangement optimization problem having a large problem scale is to be processed. The arrangement optimization problem processing apparatus includes a hyper node formation section for grouping the plurality of nodes to form a plurality of hyper nodes each formed from a set of nodes, a hyper node arrangement section for executing an optimization problem solution algorithm to determine solutions to a problem of arrangement of the plurality of hyper nodes formed by the hyper node formation section in the generation space and arranging the plurality of hyper nodes in the generation space based on one of the determined solutions.

Layout method arranging nodes corresponding to LSI elements having a connecting relationship

The present invention relates to a technique relating to a method of processing a layout optimization problem. In connection with an element layout optimization problem in which it is requested to optimally arrange a plurality of elements within a space of two or more dimension, a first algorithm executing step is carried out. In this step, when information concerning the state of initial layout of the plurality of elements is available, a genetic algorithm is executed, thereby reducing non-uniformity in density of the plurality of elements staying in the initial layout. Subsequently, a second algorithm executing step is executed. In this step, when there are input data regarding the state of layout unbalance reduction halfway stage of the plurality of elements after reduction of non-uniformity in density in the first algorithm executing step, a local layout unbalance reducing algorithm is executed, thereby further reducing non-uniformity in density of the plurality of elements staying in the layout unbalance reduction halfway stage. As a result, the layout optimization problem of optimally arranging the plurality of elements in a space is processed. In this way, an element layout optimization problem of large scale is also processed.

Method for solving a layout optimization problem, and computer-readable recording medium having a layout optimization problem processing program recorded thereon

The invention provides a technique regarding an optimal solution search method suitable for use for optimization of a system, wherein genetic algorithms can be executed at a high speed to allow an optimal solution to a problem to be searched for at a high speed. The optimal solution search method wherein candidates for solution to a problem are represented as chromosomes which are arrangements of genes and genetic operations are performed for individual chromosomes for each generation to successively update the generation to search for an optimal solution to the problem based on fitness values calculated from gene arrangements of the chromosomes.

Optimum solution search method and optimum solution search apparatus as well as storage medium in which optimum solution search program is stored

A problem solving operation apparatus obtains an optimum solution for a given problem through a combined use of a plurality of optimum solution search techniques of a genetic algorithm, and other search techniques like a hill climbing method. A combination of the optimum solution search techniques applied to each of a group of solution candidates varies according to each state. When a search efficiency in a single state is lowered, the problem solving operation apparatus immediately causes a state transition to the next state, thus enabling a search of an optimum solution through the use of another combination of more efficient optimum solution search techniques. Because a state transition constantly maintains a high search efficiency, this problem solving operation apparatus can reach an optimum solution in a short amount of time.

Problem solving operation apparatus using a state transition

A problem solver apparatus for solving optimization problems, which finds better solutions at a higher speed by utilizing both genetic algorithms and OR-based techniques. When an optimization problem is given to the problem solver apparatus, a searching strategy optimization unit creates a population of individuals using a genetic algorithm. Each individual has a chromosome to indicate a solution searching strategy. Upon receipt of such a population, a solution searching unit searches for solutions according to the strategies respectively indicated by the chromosomes of the individuals, thus obtaining candidate solutions. This group of candidate solutions is returned to the searching strategy optimization unit. The searching strategy optimization unit calculates fitness values of respective candidate solutions in the received candidate group. The searching strategy optimization unit applies some genetic operators to the individuals, thereby producing a new generation population. The produced new generation population is directed to the solution searching unit to perform another search. The problem solver apparatus repeats the above procedure until the candidate solutions show some acceptable fitness values. Lastly, the fittest candidate solution is chosen as the final solution of the optimization problem.

Apparatus for solving optimization problems and delivery planning system

A data processing apparatus has a dictionary control unit in which pieces of dictionary data stored in a dictionary buffer are compared with pieces of input data to be compressed input one after another, a piece of particular dictionary data agreeing with a piece of particular input data is expelled from the dictionary buffer, the dictionary data stored in the dictionary buffer are placed close together in a direction, and the particular input data is written in the dictionary buffer. Also, a data processing apparatus has an occurrence frequency producing editor for counting an occurrence frequency of each of types of pieces of input data to be compressed and producing an occurrence frequency table formed of a plurality of occurrence frequencies of the types of the input data to be compressed, a data comparing editor for predicting an occurrence of a piece of next input data subsequent to a piece of input data, and a code converting editor for converting the types of pieces of input data according to the occurrence prediction of the next input data in the data comparing editor on condition that a type of a piece of input data is converted into a piece of compressed data having a shorter bit length as an occurrence probability of the type of the input data is higher.

Data processing apparatus and data processing method

Lempel-ziv compression with expulsion of dictionary buffer matches

The present invention discloses a data processing system having a program structure and execution mode where an actual argument is bound to a formal argument of a function to be called by storing a pair of a variable name as the formal argument and a variable as the actual argument into a First-In-Last-Out type stack memory which is an environment list, the function called executes processings using a latest bind value of said environment list when referring to variable values, when a value of such function is obtained, the function value is returned by deleting the formal argument variable of the function from the environment list. The system includes an associative buffer memory provided externally to the stack memory, where at least the variable name and location data of variable on the environment list are stored in the associative buffer memory, and thereby the access time for referring to variables stored in the stack memory can be curtailed.

Growing community of inventors

Nakano, Japan

Akio Shinagawa