On Rank-Revealing Factorisations
SIAM Journal on Matrix Analysis and Applications
Efficient algorithms for computing a strong rank-revealing QR factorization
SIAM Journal on Scientific Computing
Matrix computations (3rd ed.)
The Multifrontal Solution of Indefinite Sparse Symmetric Linear
ACM Transactions on Mathematical Software (TOMS)
Templates for the solution of algebraic eigenvalue problems: a practical guide
Templates for the solution of algebraic eigenvalue problems: a practical guide
Robust Approximate Inverse Preconditioning for the Conjugate Gradient Method
SIAM Journal on Scientific Computing
A fast direct solver for boundary integral equations in two dimensions
Journal of Computational Physics
Some Fast Algorithms for Sequentially Semiseparable Representations
SIAM Journal on Matrix Analysis and Applications
H-matrix Preconditioners in Convection-Dominated Problems
SIAM Journal on Matrix Analysis and Applications
A Fast $ULV$ Decomposition Solver for Hierarchically Semiseparable Representations
SIAM Journal on Matrix Analysis and Applications
An Adaptive Multilevel Method for Time-Harmonic Maxwell Equations with Singularities
SIAM Journal on Scientific Computing
Parallel black box $$\mathcal {H}$$-LU preconditioning for elliptic boundary value problems
Computing and Visualization in Science
A Fast Direct Solver for a Class of Elliptic Partial Differential Equations
Journal of Scientific Computing
Construction of Data-Sparse $\mathcal{H}^2$-Matrices by Hierarchical Compression
SIAM Journal on Scientific Computing
A Rank-Revealing Method with Updating, Downdating, and Applications. Part II
SIAM Journal on Matrix Analysis and Applications
Superfast Multifrontal Method for Large Structured Linear Systems of Equations
SIAM Journal on Matrix Analysis and Applications
SIAM Journal on Matrix Analysis and Applications
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Given a symmetric positive definite matrix $A$, we compute a structured approximate Cholesky factorization $A\approx\mathbf{R}^{T}\mathbf{R}$ up to any desired accuracy, where $\mathbf{R}$ is an upper triangular hierarchically semiseparable (HSS) matrix. The factorization is stable, robust, and efficient. The method compresses off-diagonal blocks with rank-revealing orthogonal decompositions. In the meantime, positive semidefinite terms are automatically and implicitly added to Schur complements in the factorization so that the approximation $\mathbf{R}^{T}\mathbf{R}$ is guaranteed to exist and be positive definite. The approximate factorization can be used as a structured preconditioner which does not break down. No extra stabilization step is needed. When $A$ has an off-diagonal low-rank property, or when the off-diagonal blocks of $A$ have small numerical ranks, the preconditioner is data sparse and is especially efficient. Furthermore, the method has a good potential to give satisfactory preconditioning bounds even if this low-rank property is not obvious. Numerical experiments are used to demonstrate the performance of the method. The method can be used to provide effective structured preconditioners for large sparse problems when combined with some sparse matrix techniques. The hierarchical compression scheme in this work is also useful in the development of more HSS algorithms.