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- Publications
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Preconditioning Indefinite Systems in Interior Point Methods for Optimization

- L. Bergamaschi, J. Gondzio, G. Zilli
- Computer Science, Mathematics
- Comput. Optim. Appl.
- 1 July 2004

Every Newton step in an interior-point method for optimization requires a solution of a symmetric indefinite system of linear equations. Most of today's codes apply direct solution methods to perform… Expand

MIXED FINITE ELEMENTS AND NEWTON-TYPE LINEARIZATIONS FOR THE SOLUTION OF RICHARDS' EQUATION

- L. Bergamaschi, M. Putti
- Mathematics
- 20 July 1999

We present the development of a two-dimensional Mixed-Hybrid Finite Element (MHFE) model for the solution of the non-linear equation of variably saturated flow in groundwater on unstructured… Expand

Interpolating discrete advection-diffusion propagators at Leja sequences

- M. Caliari, M. Vianello, L. Bergamaschi
- Mathematics
- 1 November 2004

We propose and analyze the ReLPM (Real Leja Points Method) for evaluating the propagator ϕ(ΔtB)v via matrix interpolation polynomials at spectral Leja sequences. Here B is the large, sparse,… Expand

On eigenvalue distribution of constraint-preconditioned symmetric saddle point matrices

- L. Bergamaschi
- Computer Science, Mathematics
- Numer. Linear Algebra Appl.
- 1 August 2012

Efficient approximation of the exponential operator for discrete 2D advection-diffusion problems

- L. Bergamaschi, M. Caliari, M. Vianello
- Mathematics, Computer Science
- Numer. Linear Algebra Appl.
- 1 April 2003

In this paper we compare Krylov subspace methods with Faber series expansion for approximating the matrix exponential operator on large, sparse, non-symmetric matrices. We consider in particular the… Expand

On the Reliability of Numerical Solutions of Brine Transport in Groundwater: Analysis of Infiltration from a Salt Lake

- A. Mazzia, L. Bergamaschi, M. Putti
- Mathematics
- 1 April 2001

The density dependent flow and transport problem in groundwater is solved numerically by means of a mixed finite element scheme for the flow equation and a mixed finite element-finite volume… Expand

Inexact constraint preconditioners for linear systems arising in interior point methods

- L. Bergamaschi, J. Gondzio, M. Venturin, G. Zilli
- Mathematics, Computer Science
- Comput. Optim. Appl.
- 1 April 2007

Abstract
Issues of indefinite preconditioning of reduced Newton systems arising in optimization with interior point methods are addressed in this paper. Constraint preconditioners have shown much… Expand

Quasi-Newton preconditioners for the inexact Newton method.

- L. Bergamaschi, R. Bru, A. Martinez, M. Putti
- Mathematics
- 2006

In this paper preconditioners for solving the linear systems of the Newton method in each nonlinear iteration are studied. In particular, we define a sequence of preconditioners built by means of… Expand

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The LEM exponential integrator for advection-diffusion-reaction equations

- M. Caliari, M. Vianello, L. Bergamaschi
- Mathematics
- 20 December 2007

We implement a second-order exponential integrator for semidiscretized advection-diffusion-reaction equations, obtained by coupling exponential-like Euler and Midpoint integrators, and computing the… Expand

An Efficient Parallel MLPG Method for Poroelastic Models

- L. Bergamaschi, Ngeles Martnez, G. Pini
- Mathematics
- 1 August 2009

A meshless model, based on the Meshless Local Petrov-Galerkin (MLPG) approach, is developed and implemented in parallel for the solution of axi-symmetric poroelastic problems. The parallel code is… Expand