A parallel multigrid preconditioned conjugate gradient algorithm for groundwater flow simulations SF Ashby, RD Falgout Nuclear science and engineering 124 (1), 145-159, 1996 | 391 | 1996 |

A taxonomy for conjugate gradient methods SF Ashby, TA Manteuffel, PE Saylor SIAM Journal on Numerical Analysis 27 (6), 1542-1568, 1990 | 374 | 1990 |

The opportunities and challenges of exascale computing S Ashby, P Beckman, J Chen, P Colella, B Collins, D Crawford, ... Summary Report of the Advanced Scientific Computing Advisory Committee …, 2010 | 191 | 2010 |

A numerical investigation of the conjugate gradient method as applied to three‐dimensional groundwater flow problems in randomly heterogeneous porous media PD Meyer, AJ Valocchi, SF Ashby, PE Saylor Water Resources Research 25 (6), 1440-1446, 1989 | 84 | 1989 |

A comparison of adaptive Chebyshev and least squares polynomial preconditioning for Hermitian positive definite linear systems SF Ashby, TA Manteuffel, JS Otto SIAM Journal on Scientific and Statistical Computing 13 (1), 1-29, 1992 | 81 | 1992 |

Polynomial preconditioning for conjugate gradient methods. SF Ashby | 72 | 1989 |

ParFlow user¢s manual RM Maxwell, SJ Kollet, SG Smith, CS Woodward, RD Falgout, ... International Ground Water Modeling Center Report GWMI 1 (2009), 129, 2009 | 63 | 2009 |

Adaptive polynomial preconditioning for Hermitian indefinite linear systems SF Ashby, TA Manteuffel, PE Saylor BIT Numerical Mathematics 29 (4), 583-609, 1989 | 59 | 1989 |

Minimax polynomial preconditioning for Hermitian linear systems SF Ashby SIAM Journal on Matrix Analysis and Applications 12 (4), 766-789, 1991 | 53 | 1991 |

Analysis of subsurface contaminant migration and remediation using high performance computing AFB Tompson, RD Falgout, SG Smith, WJ Bosl, SF Ashby Advances in Water Resources 22 (3), 203-221, 1998 | 50 | 1998 |

The role of the inner product in stopping criteria for conjugate gradient iterations SF Ashby, MJ Holst, A Manteuffel, PE Saylor BIT Numerical Mathematics 41 (1), 26-52, 2001 | 48 | 2001 |

A linear algebraic analysis of diffusion synthetic acceleration for the Boltzmann transport equation SF Ashby, PN Brown, MR Dorr, AC Hindmarsh SIAM Journal on Numerical Analysis 32 (1), 128-178, 1995 | 41 | 1995 |

ChebyCode: a FORTRAN, implementation of Manteuffel's adaptive Chebyshev algorithm SF Ashby Department of Computer Science, University of Illinois at Urbana-Champaign, 1985 | 41 | 1985 |

A numerical simulation of groundwater flow and contaminant transport on the CRAY T3D and C90 Supercomputers SF Ashby, WJ Bosl, RD Falgout, SG Smith, AFB Tompson, TJ Williams The International Journal of High Performance Computing Applications 13 (1 …, 1999 | 40 | 1999 |

Use of high performance computing to examine the effectiveness of aquifer remediation AFB Tompson, SF Ashby, RD Falgout, SG Smith, TW Fogwell, ... Lawrence Livermore National Lab., 1994 | 22 | 1994 |

Multigrid preconditioned conjugate gradients for the numerical simulation of groundwater flow on the Cray T3D SF Ashby, RD Falgout, SG Smith, TW Fogwell Lawrence Livermore National Lab., CA (United States), 1994 | 19 | 1994 |

Modeling groundwater flow on MPPs SF Ashby, RD Falgout, SG Smith, AFB Tompson Proceedings of Scalable Parallel Libraries Conference, 17-35, 1993 | 19 | 1993 |

A proposed standard for iterative linear solvers SF Ashby, MK Seager Technical Report UCRL-102860, Lawrence Livermore national Laboratory, 1990 | 19 | 1990 |

Preconditioned iterative methods for discretized transport equations SF Ashby, PN Brown, MR Dorr, AC Hindmarsh Proc. International Topical Meeting on Advances in Mathematics, Computations …, 1991 | 18 | 1991 |

The Parallel Performance of a Groundwater Flow Code on the Cray T3D. SF Ashby, RD Falgout, SG Smith, AFB Tompson PPSC, 131-136, 1995 | 11 | 1995 |