EFS: Entropy First Search for Dynamic Shortest Path Problem in Large Sparse Graphs

2017 ◽  
Vol 14 (1) ◽  
pp. 367-383
Author(s):  
Quan Zhou ◽  
Hui Zhao ◽  
Huijie Zhang ◽  
Shulin Tian ◽  
Zhen Liu
Keyword(s):  
Shortest Path ◽  
Shortest Paths ◽  
Shortest Path Problem ◽  
Search Process ◽  
Single Source ◽  
Solution Path ◽  
Sparse Graphs ◽  
Path Search ◽  
Speed Up ◽  
Shortest Path Search

Searching the dynamic shortest path is a hot topic recently. In this paper we proposed a new method to solve the dynamic single source shortest paths (SSSP) problem in sparse graphs. The main contributions are three: firstly, in the preprocessing stage, we use the unreachable and unstartable characteristics to avoid most of the non-solution path search. Secondly, Entropy first search (EFS) is introduced to speed up the search process in finding the possible shortest path and then the algorithm can converges as soon as possible. In addition, the update algorithm for dynamic shortest path search is proposed for practical use. The experiments in large random sparse graphs show the efficiency and benefits of the proposed method.

Accelerating Traffic Assignment with Customizable Contraction Hierarchies

2020 ◽  
Vol 2674 (1) ◽  
pp. 188-196 ◽  
Author(s):  
Arne Schneck ◽  
Klaus Nökel
Keyword(s):  
Shortest Path ◽  
Traffic Assignment ◽  
Shortest Path Problem ◽  
Transport Modeling ◽  
The Past ◽  
Acceleration Techniques ◽  
Network Loading ◽  
Enormous Amount ◽  
Path Search ◽  
Shortest Path Search

In many algorithms for traffic assignment, the most time-consuming step is shortest path search between all O–D pairs. Almost unnoticed by the transport modeling community, there has been an enormous amount of research on acceleration techniques for the shortest path problem in road networks in the past decade. These techniques usually divide the problem into a relatively expensive preprocessing phase and a significantly accelerated search phase. In this paper, the recently developed customizable contraction hierarchies are used for both shortest path search and network loading in the bi-conjugate Frank–Wolfe algorithm. For the largest test network, this approach achieves a speedup by a factor of 42 compared with a straightforward implementation of Dijkstra’s algorithm.

scholarly journals MENENTUKAN RUTE TERPENDEK DENGAN MENGGUNAKAN ALGORITMA FLOYD-WARSHALL DALAM PENDISTRIBUSIAN BARANG PADA PT. RAPY RAY PUTRATAMA

2018 ◽  
Vol 4 (1) ◽  
Author(s):  
M Ridwan Mukti ◽  
Mulyono . .
Keyword(s):  
Shortest Path ◽  
Minimum Distance ◽  
Shortest Path Problem ◽  
Search Result ◽  
Shortest Route ◽  
Shortest Distance ◽  
Path Search ◽  
Distance Data ◽  
Shortest Path Search ◽  
Route Search

ABSTRAKMasalah pendistribusian pada perusahaan adalah masalah yang sangat penting untuk diperhatikan. Pada dasarnya pendistribusian barang akan sangat menghemat perusahaan dalam berbagai hal.Pencarian rute terpendek yang dilakukan pada PT. Rapy Ray Putratama Medan dilakukan dengan menghubungkan berbagai macem outlet dan juga termasuk beberapa outletnya adalah PT. Rapy Ray Putratama cabang medan. Permasalah rute terpendek ini dapat disesaikan dengan menggunakan salah satu metode pencarian rute terpendek yaitu algoritma Floyd-Warshall. Penelitian ini bertujuan untuk mengetahui hasil dari rute yang akan dipilih sebagai saran atau masukan kepada Perusahaan. Untuk hasil pencarian rute terpendek dengan menggunakan algoritma Floyd-Warshallyang diimplementasikan dalam pemrograman Codeblocks:: adalah jarak dari PT ke outlet maupun dari outlet ke outlet memiliki jarak yang paling minimum. Setelah itu, dapat ditentukan rute terpendek yang akan dipilih oleh salesman dalam pendistribusian yang telah didapatkan pada program tersebut. Data yang diinput adalah data jarak. Output yang dihasilkan program adalah jarak terpendek. Dengan penghematan jarak yang telah dilakukan. Pembentukan rute usulan yang dihasilkan dengan menggunakan metode algoritma Floyd-Warshall menghasilkan rute yang lebih dekat dengan total jarak penghematan adalah 10.97 % (51.304 km).Kata kunci: Pendistribusian, Pencarian rute terpendek, algoritma Floyd-Warshall. ABSTRACTThe problem of distribution to the company is a very important issue to notice. Basically the distribution of goods will greatly save the company expense in various ways. The searching for the shortest route done at PT. Rapy Ray Putratama Medan conducted by connecting various kinds of outlets and also including some outlets at PT. Rapy Ray Putratama Medan branch. This shortest path problem can be solved by using one of the shortest path search methods the Floyd-Warshall algorithm. This study aims to determine the results of the route to be selected as advice or input to the company. For the shortest route search result using Floyd-Warshall algorithm implemented in codeblocks programming is the distance from PT. Rapy Ray Putratamata outlet and from outlet to outlet which has the minimum distance. Subsequently, it can be determined the shortest route that will be selected by the salesman in the distribution that has been attained on the program. The inputted data is the distance data. The output produced by the program is the shortest distance by saving the distance that has been done through the algorithm. The proposed route formatted using the Floyd-Warshall algorithm method resulted in a route closer to the total distance of a saving distance of 10.97% (51,304 km). Keywords: Distribution, the shortest path searching, Floyd-Warshall algorithm.

scholarly journals Methods for finding shortest paths on graphs in organizational and economic systems and their implementation

2019 ◽  
pp. 368-375
Author(s):  
V М Ramzaev ◽  
I N Khaimovich ◽  
I V Martynov
Keyword(s):  
Shortest Path ◽  
Shortest Paths ◽  
Search Algorithms ◽  
Economic Systems ◽  
Running Time ◽  
Path Search ◽  
Shortest Path Search

The article implements the functions in Postgre SQL DBMS, finding the shortest paths on graphs, using the wave algorithm method, the Dijkstra’s method and the Floyd method. The authors determined models of dependencies of the running time of implementations of the shortest-path search algorithms on graphs on the number of graph vertices experimentally. A comparison of the data obtained as a result of the study was carried out to find the best applications of implementations of the shortest path search algorithms in the Postgre SQL DBMS.

Tight Analysis of the (1+1)-EA for the Single Source Shortest Path Problem

2011 ◽  
Vol 19 (4) ◽  
pp. 673-691 ◽  
Author(s):  
Benjamin Doerr ◽  
Edda Happ ◽  
Christian Klein
Keyword(s):  
Evolutionary Algorithms ◽  
Shortest Path ◽  
High Probability ◽  
Shortest Paths ◽  
Type Inequality ◽  
Random Variables ◽  
Shortest Path Problem ◽  
Single Source ◽  
Coupon Collector ◽  
A New Technique

We conduct a rigorous analysis of the (1+1) evolutionary algorithm for the single source shortest path problem proposed by Scharnow, Tinnefeld, and Wegener (The analyses of evolutionary algorithms on sorting and shortest paths problems, 2004, Journal of Mathematical Modelling and Algorithms, 3(4):349–366). We prove that with high probability, the optimization time is O(n2 max{ℓ, log(n)}), where ℓ is the smallest integer such that any vertex can be reached from the source via a shortest path having at most ℓ edges. This bound is tight. For all values of n and ℓ we provide a graph with edge weights such that, with high probability, the optimization time is of order Ω(n2 max{ℓ, log(n)}). To obtain such sharp bounds, we develop a new technique that overcomes the coupon collector behavior of previously used arguments. Also, we exhibit a simple Chernoff type inequality for sums of independent geometrically distributed random variables, and one for sequences of random variables that are not independent, but show a desired behavior independent of the outcomes of the previous random variables. We are optimistic that these tools find further applications in the analysis of evolutionary algorithms.

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