Blocked Cholesky factorization updates of the Riccati recursion using hyperbolic Householder transformations

Fuente: arXiv
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Hauptverfasser: Pas, Pieter, Patrinos, Panagiotis
Format: Preprint
Veröffentlicht: 2025
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author Pas, Pieter
Patrinos, Panagiotis
author_facet Pas, Pieter
Patrinos, Panagiotis
contents Newton systems in quadratic programming (QP) methods are often solved using direct Cholesky or LDL factorizations. When the linear systems in successive iterations differ by a low-rank modification (as is common in active set and augmented Lagrangian methods), updating the existing factorization can offer significant performance improvements over recomputing a full Cholesky factorization. We review the hyperbolic Householder transformation, and demonstrate its usefulness in describing low-rank Cholesky factorization updates. By applying this hyperbolic Householder-based framework to the well-known Riccati recursion for solving saddle-point problems with optimal control structure, we develop a novel algorithm for updating the factorizations used in optimization solvers for optimal control. Specifically, the proposed method can be used to efficiently solve the semismooth Newton systems that are at the core of the augmented Lagrangian-based QPALM-OCP solver. An optimized open-source implementation of the proposed factorization update routines is provided as well.
format Preprint
id arxiv_https___arxiv_org_abs_2503_15372
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Blocked Cholesky factorization updates of the Riccati recursion using hyperbolic Householder transformations
Pas, Pieter
Patrinos, Panagiotis
Optimization and Control
Systems and Control
49M15, 65F05
Newton systems in quadratic programming (QP) methods are often solved using direct Cholesky or LDL factorizations. When the linear systems in successive iterations differ by a low-rank modification (as is common in active set and augmented Lagrangian methods), updating the existing factorization can offer significant performance improvements over recomputing a full Cholesky factorization. We review the hyperbolic Householder transformation, and demonstrate its usefulness in describing low-rank Cholesky factorization updates. By applying this hyperbolic Householder-based framework to the well-known Riccati recursion for solving saddle-point problems with optimal control structure, we develop a novel algorithm for updating the factorizations used in optimization solvers for optimal control. Specifically, the proposed method can be used to efficiently solve the semismooth Newton systems that are at the core of the augmented Lagrangian-based QPALM-OCP solver. An optimized open-source implementation of the proposed factorization update routines is provided as well.
title Blocked Cholesky factorization updates of the Riccati recursion using hyperbolic Householder transformations
topic Optimization and Control
Systems and Control
49M15, 65F05
url https://arxiv.org/abs/2503.15372