Sémiotique, numérique et communication

Représentations parcimonieuses et applications en communication numérique

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau...

Analyse numérique et réduction de réseaux

The algorithmic facet of euclidean lattices is a frequent tool in computer science and mathematics. It mainly relies on the LLL reduction, making worthwile efficiency improvements. Schnorr proved that the LLL algorithm can be speeded up if one computes approximations to the underlying Gram-Schmidt orthogonalisations. Without approximations, these computations dominate the cost of the reduction....

et fort courant avec commande numérique

Simulation moléculaire et effets d'environnement - Une perspective mathématique et numérique

Calculs pour les matrices denses : coût de communication et stabilité numérique. (Dense matrix computations : communication cost and numerical stability)

This dissertation focuses on a widely used linear algebra kernel to solve linear systems, that is the LU decomposition. Usually, to perform such a computation one uses the Gaussian elimination with partial pivoting (GEPP). The backward stability of GEPP depends on a quantity which is referred to as the growth factor, it is known that in general GEPP leads to modest element growth in practice. H...