Title
Efficient handling of complex shift parameters in the low-rank Cholesky factor ADI method
Abstract
The solution of large-scale Lyapunov equations is a crucial problem for several fields of modern applied mathematics. The low-rank Cholesky factor version of the alternating directions implicit method (LRCF-ADI) is one iterative algorithm that computes approximate low-rank factors of the solution. In order to achieve fast convergence it requires adequate shift parameters, which can be complex if the matrices defining the Lyapunov equation are unsymmetric. This will require complex arithmetic computations as well as storage of complex data and thus, increase the overall complexity and memory requirements of the method. In this article we propose a novel reformulation of LRCF-ADI which generates real low-rank factors by carefully exploiting the dependencies of the iterates with respect to pairs of complex conjugate shift parameters. It significantly reduces the amount of complex arithmetic calculations and requirements for complex storage. It is hence often superior in terms of efficiency compared to other real formulations.
Year
DOI
Venue
2013
10.1007/s11075-012-9569-7
Numerical Algorithms
Keywords
Field
DocType
ADI iteration,Matrix equations,Solvers,Algorithmic enhancement
Alternating direction implicit method,Lyapunov function,Mathematical optimization,Lyapunov equation,Complex number,Mathematical analysis,Iterative method,Algorithm,Complex data type,Mathematics,Complex conjugate,Cholesky decomposition
Journal
Volume
Issue
ISSN
62
2
1017-1398
Citations 
PageRank 
References 
14
0.96
11
Authors
3
Name
Order
Citations
PageRank
Peter Benner1825114.06
Patrick Kürschner2375.29
Jens Saak35911.00