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Modified controlled Cholesky factorization for preconditioning linear systems from the interior-point method
The interior-point method solves large linear programming problems in a few iterations. Each iteration requires computing the solution to one or more linear systems. This constitutes the most expensive step of the method and reducing the time to solve these linear systems is a way of improving the m...
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Published in: | Computational & applied mathematics 2021-06, Vol.40 (4), Article 154 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The interior-point method solves large linear programming problems in a few iterations. Each iteration requires computing the solution to one or more linear systems. This constitutes the most expensive step of the method and reducing the time to solve these linear systems is a way of improving the method’s performance. Iterative methods such as the preconditioned conjugate gradient method can be used to solve them. Incomplete Cholesky factorization can be used as a preconditioner to the problem. However, breakdowns may occur during incomplete factorizations and corrections on the diagonal may be required. This correction is accomplished by adding a positive number to diagonal elements of the linear system matrix and the factorization of the new matrix is restarted. In this work, we propose modifications to controlled Cholesky factorization to avoid or decrease the number of refactorizations of diagonally modified matrices. Computational results show that the proposed techniques can reduce the time needed for solving linear programming problems by the interior-point method. |
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ISSN: | 2238-3603 1807-0302 |
DOI: | 10.1007/s40314-021-01544-0 |