Angeles Martinez

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Preconditioners for the Conjugate Gradient method are studied to solve the Newton system with symmetric positive definite (SPD) Jacobian. Following the theoretical work in [1] we start from a given approximation of the inverse of the initial Jacobian, and we construct a sequence of preconditioners by means of a low rank update, for the linearized systems(More)
RATIONALE Respiratory polygraphy is an accepted alternative to polysomnography (PSG) for sleep apnea/hypopnea syndrome (SAHS) diagnosis, although it underestimates the apnea-hypopnea index (AHI) because respiratory polygraphy cannot identify arousals. OBJECTIVES We performed a multicentric, randomized, blinded crossover study to determine the agreement(More)
Pyrroloazepinones 8a-j and 9a-j were designed by structural modification of lead compound 3. These compounds were tested on five tumor cell lines to determine the role of the azeto ring and the 2-methyl substituent in the cytotoxicity of compound 3. Our results show that compounds 8a-j (R1=CH3) have dramatically reduced cytotoxicity, resulting from the loss(More)
In this paper we propose and describe a parallel implementation of a block preconditioner for the solution of saddle point linear systems arising from Finite Element (FE) discretization of 3D coupled consolidationproblems. TheMixedConstraint Preconditioner developed in [L. Bergamaschi,M. Ferronato, G. Gambolati,Mixed constraint preconditioners for the(More)
In this paper we propose a parallel implementation of the FSAI preconditioner to accelerate the PCG method in the solution of symmetric positive definite linear systems of very large size. This preconditioner is used as building block for the construction of an indefinite Inexact Constraint Preconditioner (ICP) for saddle point-type linear systems arising(More)
This report describes the case of a 4-year-old boy diagnosed with Smith-Magenis syndrome in whom treatment with a beta(1)-adrenergic antagonist in the morning (to suppress the diurnal melatonin secretion) and melatonin in the evening (to generate a nocturnal peak of melatonin) improved his sleep quality, evaluated by polysomnographic studies.
In this work, preconditioners for the iterative solution by Krylov methods of the linear systems arising at each Newton iteration are studied. The preconditioner is defined by means of a Broyden-type rank-one update of a given initial preconditioner, at each nonlinear iteration, as described in [5] where convergence properties of the scheme are(More)
The present paper describes a parallel preconditioned algorithm for the solution of partial eigenvalue problems for large sparse symmetric matrices, on parallel computers. Namely, we consider the Deflation-Accelerated Conjugate Gradient (DACG) algorithm accelerated by factorized sparse approximate inverse (FSAI) type preconditioners. We present an enhanced(More)