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Randomized Rounding

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  • First Online:
Encyclopedia of Algorithms
  • 135 Accesses

Years and Authors of Summarized Original Work

  • 1987; Raghavan, Thompson

Problem Definition

Randomized rounding is a technique for designing approximation algorithms for NP-hard optimization problems. Many combinatorial optimization problems can be represented as 0-1 integer linear programs; that is, integer linear programs in which variables take values in \( { \{0,1\} } \). While 0-1 integer linear programming is NP-hard, the rational relaxations (also referred to as fractional relaxations) of these linear programs are solvable in polynomial time [12, 13]. Randomized rounding is a technique to construct a provably good solution to a 0-1 integer linear program from an optimum solution to its rational relaxation by means of a randomized algorithm.         

Let Π be a 0-1 integer linear program with variables \( { x_i \in \{0,1\} } \), \( { 1 \le i \le n } \). Let Π R be the rational relaxation of Π obtained by replacing the \( { x_i \in \{0,1\} } \) constraints by \( { x_i \in [0,1], 1 \le i \le...

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Recommended Reading

  1. Alon N, Spencer JH (1991) The probabilistic method. Wiley, New York

    MATH  Google Scholar 

  2. Andrews M, Zhang L (2005) Hardness of the undirected congestion minimization problem. In: STOC’05: proceedings of the thirty-seventh annual ACM symposium on theory of computing. ACM, New York, pp 284–293

    Google Scholar 

  3. Arora S, Rao S, Vazirani UV (2004) Expander flows, geometric embeddings and graph partitioning. In: STOC, pp 222–231

    Google Scholar 

  4. Calinescu G, Karloff HJ, Rabani Y (2000) An improved approximation algorithm for multiway cut. J Comput Syst Sci 60(3):564–574

    Article  MathSciNet  MATH  Google Scholar 

  5. Chernoff H (1952) A measure of the asymptotic efficiency for tests of a hypothesis based on the sum of observations. Ann Math Stat 23:493–509

    Article  MathSciNet  MATH  Google Scholar 

  6. Chuzhoy J, Guruswami V, Khanna S, Talwar K (2007) Hardness of routing with congestion in directed graphs. In: STOC’07: proceedings of the thirty-ninth annual ACM symposium on theory of computing. ACM, New York, pp 165–178

    Google Scholar 

  7. Goemans MX, Williamson DP (1994) New 3/4-approximation algorithms for the maximum satisfiability problem. SIAM J Discret Math 7:656–666

    Article  MathSciNet  MATH  Google Scholar 

  8. Goemans MX, Williamson DP (1995) Improved approximation algorithms for maximum cut and satisfiability problems using semidefinite programming. J ACM 42(6):1115–1145

    Article  MathSciNet  MATH  Google Scholar 

  9. Guruswami V, Khanna S, Rajaraman R, Shepherd B, Yannakakis M (2003) Near-optimal hardness results and approximation algorithms for edge-disjoint paths and related problems. J Comput Syst Sci 67:473–496

    Article  MathSciNet  MATH  Google Scholar 

  10. Hochbaum DS (1982) Approximation algorithms for the set covering and vertex cover problems. SIAM J Comput 11(3):555–556

    Article  MathSciNet  MATH  Google Scholar 

  11. Hoeffding W (1956) On the distribution of the number of successes in independent trials. Ann Math Stat 27:713–721

    Article  MathSciNet  Google Scholar 

  12. Karmarkar N (1984) A new polynomial-time algorithm for linear programming. Combinatorica 4:373–395

    Article  MathSciNet  MATH  Google Scholar 

  13. Khachiyan LG (1979) A polynomial algorithm for linear programming. Sov Math Dokl 20:191–194

    MATH  Google Scholar 

  14. Raghavan P, Thompson C (1987) Randomized rounding: a technique for provably good algorithms and algorithmic proofs. Combinatorica 7

    Article  MathSciNet  MATH  Google Scholar 

  15. Srinivasan A (1995) Improved approximations of packing and covering problems. In: Proceedings of the 27th annual ACM symposium on theory of computing, pp 268–276

    Google Scholar 

  16. Vazirani V (2003) Approximation algorithms. Springer

    Google Scholar 

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Rajaraman, R. (2016). Randomized Rounding. In: Kao, MY. (eds) Encyclopedia of Algorithms. Springer, New York, NY. https://doi.org/10.1007/978-1-4939-2864-4_327

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