Automation of Determination of Optimal Intra-Compute Node Parallelism

Maximizing the productivity of modern multicore and manycore chips requires optimizing parallelism at the compute node level. This is, however, a complex multi-step process. It is an iterative method requiring determining optimal degrees of parallel scalability and optimizing memory access behavior. Further, there are multiple cases to be considered, programs which use only MPI or OpenMP and hybrid (MPI +OpenMP) programs. This paper presents a set of three coordinated workflows for determining the optimal parallelism at the program level for MPI programs and at the loop level for hybrid (MPI+OpenMP) cases. The paper also details mostly automated implementations of these workflows using the PerfExpert infrastructure. Finally the paper presents case studies demonstrating both the applicability and the effectiveness of optimizing parallelism at the compute node level. The results shown in the paper will provide valuable information to further advance in the full automation of the workflows. The software implementing the parallelism scalability optimization is open source and available for download.Texas Advanced Computing Center (TACC)Computer Scienc

Oxygen vacancies in strained SrTiO3_{3} thin films: formation enthalpy and manipulation

We report the enthalpy of oxygen vacancy formation in thin films of electron-doped SrTiO$_{3}$, under different degrees of epitaxial stress. We demonstrate that both compressive and tensile strain decrease this energy at a very similar rate, and promote the formation of stable doubly ionized oxygen vacancies. Moreover, we also show that unintentional cationic vacancies introduced under typical growth conditions, produce a characteristic rotation pattern of TiO$_6$ octahedra. The local concentration of oxygen vacancies can be modulated by an electric field with an AFM tip, changing not only the local electrical potential, but also producing a non-volatile mechanical response whose sign (up/down) can be reversed by the electric field.Comment: Physical Review B (accepted for publication

Some linear Jacobi structures on vector bundles

We study Jacobi structures on the dual bundle $A^\ast$ to a vector bundle $A$ such that the Jacobi bracket of linear functions is again linear and the Jacobi bracket of a linear function and the constant function 1 is a basic function. We prove that a Lie algebroid structure on $A$ and a 1-cocycle $\phi \in \Gamma (A^\ast)$ induce a Jacobi structure on $A^\ast$ satisfying the above conditions. Moreover, we show that this correspondence is a bijection. Finally, we discuss some examples and applications.Comment: 6 pages, To appear in C. R. Acad. Sci. Paris, S\'erie

Diaglexia: una aplicación informática para el diagnóstico de la dislexia

[Resumen] En esta comunicación pretendemos dar una opción diferente al profesor de Audición y Lenguaje, al Logopeda o al Psicopedagogo de un departamento de orientación, a la hora de hacer un diagnóstico a un discente con trastornos lectoescritores, en concreto la dislexia. Se trata de una aplicación informática llamada Diaglexia,en la que se ponen a disposición del niño las herramientas de la nueva era, la tecnología informática. Se pretende explorar los fallos del sujeto a la vez que se divierte, realmente este programa pide una segunda parte, en el que se propongan diversas actividades para la intervención o reeducación de la dislexia. Por otra parte, hay una segunda comunicación que explica el manual de usuari

Co-located wave and offshore wind farms: A preliminary approach to the shadow effect

In recent years, with the consolidation of offshore wind technology and the progress carried out for wave energy technology, the option of combine both technologies has arisen. This combination rest mainly in two main reasons: in one hand, to increase the sustainability of both energies by means of a more rational harnessing of the natural resources; in the other hand, to reduce the costs of both technologies by sharing some of the most important costs of an offshore project. In addition to these two powerful reasons there are a number of technology synergies between wave and wind systems which makes their combination even more suitable. Co-located projects are one of the alternatives to combine wave-wind systems, and it is specially for these project were so-called shadow effect synergy becomes meaningful. In particular, this paper deals with the co-location of Wave Energy Conversion (WEC) technologies into a conventional offshore wind farm. More specifically, an overtopping type of WEC technology was considered in this work to study the effects of its co-location with a conventional offshore wind park. This study aims to give a preliminary approach to the shadow effect and its implications for both wave and offshore wind energies