scholarly journals Two‐stage stochastic minimum s  −  t cut problems: Formulations, complexity and decomposition algorithms

Networks ◽  
2019 ◽  
Vol 75 (3) ◽  
pp. 235-258
Author(s):  
Steffen Rebennack ◽  
Oleg A. Prokopyev ◽  
Bismark Singh
2014 ◽  
Vol 157 (1) ◽  
pp. 219-243 ◽  
Author(s):  
Xiao Liu ◽  
Simge Küçükyavuz ◽  
James Luedtke

2014 ◽  
Vol 26 (4) ◽  
pp. 825-847 ◽  
Author(s):  
Dimitri J. Papageorgiou ◽  
Ahmet B. Keha ◽  
George L. Nemhauser ◽  
Joel Sokol

2020 ◽  
Vol 32 (3) ◽  
pp. 805-821
Author(s):  
Kevin Ryan ◽  
Shabbir Ahmed ◽  
Santanu S. Dey ◽  
Deepak Rajan ◽  
Amelia Musselman ◽  
...  

Scenario decomposition algorithms for stochastic programs compute bounds by dualizing all nonanticipativity constraints and solving individual scenario problems independently. We develop an approach that improves on these bounds by reinforcing a carefully chosen subset of nonanticipativity constraints, effectively placing scenarios into groups. Specifically, we formulate an optimization problem for grouping scenarios that aims to improve the bound by optimizing a proxy metric based on information obtained from evaluating a subset of candidate feasible solutions. We show that the proposed grouping problem is NP-hard in general, identify a polynomially solvable case, and present two formulations for solving the problem: a matching formulation for a special case and a mixed-integer programming formulation for the general case. We use the proposed grouping scheme as a preprocessing step for a particular scenario decomposition algorithm and demonstrate its effectiveness in solving standard test instances of two-stage 0–1 stochastic programs. Using this approach, we are able to prove optimality for all previously unsolved instances of a standard test set. Additionally, we implement this scheme as a preprocessing step for PySP, a publicly available and widely used implementation of progressive hedging, and compare this grouping approach with standard grouping approaches on large-scale stochastic unit commitment instances. Finally, the idea is extended to propose a finitely convergent algorithm for two-stage stochastic programs with a finite feasible region.


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