Approximation algorithm

In computer science and operations research, approximation algorithms are efficient algorithms that find approximate solutions to optimization problems (in particular NP-hard problems) with provable guarantees on the distance of the returned solution to the optimal one. Approximation algorithms naturally arise in the field of theoretical computer science as a consequence of the widely believed P ≠ NP conjecture. Under this conjecture, a wide class of optimization problems cannot be solved exactly in polynomial time. The field of approximation algorithms, therefore, tries to understand how closely it is possible to approximate optimal solutions to such problems in polynomial time. In an overwhelming majority of the cases, the guarantee of such algorithms is a multiplicative one expressed as

Comment
enIn computer science and operations research, approximation algorithms are efficient algorithms that find approximate solutions to optimization problems (in particular NP-hard problems) with provable guarantees on the distance of the returned solution to the optimal one. Approximation algorithms naturally arise in the field of theoretical computer science as a consequence of the widely believed P ≠ NP conjecture. Under this conjecture, a wide class of optimization problems cannot be solved exactly in polynomial time. The field of approximation algorithms, therefore, tries to understand how closely it is possible to approximate optimal solutions to such problems in polynomial time. In an overwhelming majority of the cases, the guarantee of such algorithms is a multiplicative one expressed as
Has abstract
enIn computer science and operations research, approximation algorithms are efficient algorithms that find approximate solutions to optimization problems (in particular NP-hard problems) with provable guarantees on the distance of the returned solution to the optimal one. Approximation algorithms naturally arise in the field of theoretical computer science as a consequence of the widely believed P ≠ NP conjecture. Under this conjecture, a wide class of optimization problems cannot be solved exactly in polynomial time. The field of approximation algorithms, therefore, tries to understand how closely it is possible to approximate optimal solutions to such problems in polynomial time. In an overwhelming majority of the cases, the guarantee of such algorithms is a multiplicative one expressed as an approximation ratio or approximation factor i.e., the optimal solution is always guaranteed to be within a (predetermined) multiplicative factor of the returned solution. However, there are also many approximation algorithms that provide an additive guarantee on the quality of the returned solution. A notable example of an approximation algorithm that provides both is the classic approximation algorithm of Lenstra, Shmoys and Tardos for scheduling on unrelated parallel machines. The design and analysis of approximation algorithms crucially involves a mathematical proof certifying the quality of the returned solutions in the worst case. This distinguishes them from heuristics such as annealing or genetic algorithms, which find reasonably good solutions on some inputs, but provide no clear indication at the outset on when they may succeed or fail. There is widespread interest in theoretical computer science to better understand the limits to which we can approximate certain famous optimization problems. For example, one of the long-standing open questions in computer science is to determine whether there is an algorithm that outperforms the 1.5 approximation algorithm of Christofides to the metric traveling salesman problem. The desire to understand hard optimization problems from the perspective of approximability is motivated by the discovery of surprising mathematical connections and broadly applicable techniques to design algorithms for hard optimization problems. One well-known example of the former is the Goemans–Williamson algorithm for maximum cut, which solves a graph theoretic problem using high dimensional geometry.
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Algorithms
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Approximation algorithm
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enApproximation algorithm
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Algorithm
Approximation
Approximation Algorithms for NP-Hard problems
Approximation-preserving reduction
APX
Cambridge University Press
Category:Approximation algorithms
Category:Computational complexity theory
Charles E. Leiserson
Christofides algorithm
Clifford Stein
Clique problem
Computer science
Constant factor approximation algorithm
Convex programming
David S. Johnson
David Shmoys
Domination analysis
Dorit S. Hochbaum
Dynamic programming
Ellipsoid method
Euclidean traveling salesman problem
Éva Tardos
Exact algorithm
Genetic algorithm
Gerhard J. Woeginger
Graph coloring
Greedy algorithm
Hardness of approximation
Heuristic (computer science)
Independent set (graph theory)
Introduction to Algorithms
Jan Karel Lenstra
Johan Håstad
Joseph S. B. Mitchell
Knapsack problem
Linear programming
Linear programming relaxation
Local search (optimization)
Marek Karpinski
Matching (graph theory)
MAX-3SAT
Maximum cut
Maximum satisfiability problem
NP-completeness
NP-hardness
Operations research
Optimization problem
P = NP
PCP theorem
Polynomial time approximation scheme
Polynomial-time approximation scheme
P versus NP problem
Reduction (complexity)
Ronald L. Rivest
Sanjeev Arora
Scheduling (computing)
Semidefinite programming
Set cover problem
Simulated annealing
Theoretical computer science
Thomas H. Cormen
Threshold of approximability
Time complexity
Travelling salesman problem
Unique games conjecture
Vertex cover
SameAs
4500954-5
4ohTC
Algorithme d'approximation
Algoritmo de aproximação
Algoritmo de aproximación
Algoritmo di approssimazione
Algorytm aproksymacyjny
Approximation algorithm
Approximationsalgorithmus
Aproximační algoritmy
m.02qc78
Q621751
Thuật toán xấp xỉ
Аппроксимационный алгоритм
Апроксимациони алгоритам
Апроксимаційний алгоритм
אלגוריתם קירוב
الگوریتم تقریبی
ขั้นตอนวิธีการประมาณ
近似アルゴリズム
近似算法
근사 알고리즘
SeeAlso
Galactic algorithm
Subject
Category:Approximation algorithms
Category:Computational complexity theory
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