Application of block Krylov subspace algorithms to the Wilson-Dirac equation with multiple right-hand sides in lattice QCD

It is well known that the block Krylov subspace solvers work efficiently for some cases of the solution of differential equations with multiple right-hand sides. In lattice QCD calculation of physical quantities on a given configuration demands us to solve the Dirac equation with multiple sources. We show that a new block Krylov subspace algorithm recently proposed by the authors reduces the computational cost significantly without loosing numerical accuracy for the solution of the O(a)-improved Wilson-Dirac equation.Comment: 12 pages, 5 figure

Trajectory piecewise linear approach for nonlinear differential-algebraic equations in circuit simulation

In this paper we extend the Trajectory Piecewise Linear (TPWL) model order reduction (MOR) method for nonlinear differential algebraic equations (DAE). The TPWL method is based on combining several linear reduced models at different time points, which are created along a typical trajectory, to approximate the full nonlinear model.We discuss how to select the linearization tuples for linearization and the choice of linear MOR method. Then we study how to combine the local linearized reduced systems to create a global TPWL model. Finally, we show a numerical result.</p

: Climatic and biodiversity characterization in the Late Middle Pleistocene from the vertebrate fauna of Lazaret cave (Nice, France)

colloque Q6, Montpellier 2008International audienceThe Lazaret cave has yielded numerous Acheulean lithic industries and some anteneanderthal remains, but also an abundant vertebrate fauna (amphibians, reptiles, birds and mammals) revealing an important specific richness. The various faunal associations, as well as the evolutionary stage of some species, indicate that the archaeological deposits (Complex C) date from the last glacial period of the Middle Pleistocene (MIS 6). The interdisciplinary study of fauna from subcomplexes CIII and CII sup. suggests a variety of continental landscapes linked to a relatively cold climate that was moderated by the southern position of the site. The presence of cold climate species no longer present in the region implies colder and more humid conditions than at present. Fluctuations are perceptible throughout the sequence, as indicated by variation in species abundance and species. A relative decrease in temperature and a gradual opening of the landscape occurred between subcomplexes CII sup. and CIII. The faunal spectrum of the Lazaret cave provides a relativey accurate reflection of the palaeobiodiversity of southern France at the end of the Middle Pleistocene (MIS 6).La grotte du Lazaret a livré de nombreuses industries acheuléennes, plusieurs restes d'anténéanderthaliens et de très nombreux restes de vertébrés (amphibiens, reptiles, oiseaux et mammifères) reflétant une importante richesse spécifique. Les différentes associations fauniques, ainsi que le degré d'évolution de certaines espèces, permettent d'attribuer les dépôts archéologiques au Pléistocène moyen final (MIS 6), en accord avec les datations radiométriques. L'étude interdisciplinaire des ensembles stratigraphiques CIII et CII supérieur a permis de reconstituer le cadre paléoclimatique et paléoenvironnemental, et de mettre en évidence une certaine variété de paysages continentaux liés à un climat relativement froid, toutefois tempéré par la position méridionale du site. La présence d'espèces de climat froid actuellement disparues du biome méditerranéen implique l'existence de conditions plus fraîches et plus humides qu'aujourd'hui. Des fluctuations sont cependant perceptibles tout au long de la séquence au travers des variations de faunes, au niveau spécifique et quantitatif, montrant une relative intensification du froid et une ouverture progressive du milieu entre les ensembles CII sup. et CIII. Le spectre faunique de la grotte du Lazaret fournit un reflet assez juste de la paléobiodiversité dans le Sud-Est de la France à la fin du Pléistocène moyen (MIS6)

Influence of secondary void damage in the matrix material around voids

The mechanism of ductile damage caused by secondary void damage in the matrix around primary voids is studied by large strain, finite element analysis. A cylinder embedding an initially spherical void, a plane stress cell with a circular void and plane strain cell with a cylindrical or a flat void are analysed under different loading conditions. Secondary voids of smaller scale size nucleate in the strain hardening matrix, according to the requirements of some stress/strain criteria. Their growth and coalescence, handled by the empty element technique, demonstrate distinct mechanisms of damage as circumstances change. The macroscopic stress-strain curves are decomposed and illustrated in the form of the deviatoric and the volumetric parts. Concerning the stress response and the void growth prediction, comparisons are made between the present numerical results and those of previous authors. It is shown that loading condition, void growth history and void shape effect incorporated with the interaction between two generations of voids should be accounted for besides the void volume fraction