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Gianluca Argentini

Publications and source records attributed to Gianluca Argentini.

29 records · Page 2Linked to original sources
arXiv2005

An estimate of accuracy for interpolant numerical solutions of a PDE problem

In this paper we present an estimate of accuracy for a piecewise polynomial approximation of a classical numerical solution to a non linear differential problem. We suppose the numerical solution U is computed using a grid with a small linear step and interval time Tu, while the polynomial approximation V is an interpolation of the values of a numerical solution on a less fine grid and interval time Tv << Tu. The estimate shows that the interpolant solution V can be, under suitable hypotheses, a good approximation and in general its computational cost is much lower of the cost of the fine numerical solution. We present two possible applications to linear case and periodic case.

math.NA↗
arXiv2004

Using sparse matrices and splines-based interpolation in computational fluid dynamics simulations

In this relation I present a technique of construction and fast evaluation of a family of cubic polynomials for analytic smoothing and graphical rendering of particles trajectories for flows in a generic geometry. The principal result of the work was implementation and test of a method for interpolating 3D points by regular parametric curves and their fast and efficient evaluation for a good resolution of rendering. For the purpose a parallel environment using a multiprocessor cluster architecture has been used. This work has been developed for the Research and Development Department of my company for planning advanced customized models of industrial burners.

math.NA↗
arXiv2004

Using matrices in post-processing phase of CFD simulations

In this work I present a technique of construction and fast evaluation of a family of cubic polynomials for analytic smoothing and graphical rendering of particles trajectories for flows in a generic geometry. The principal result of the work was implementation and test of a method for interpolating 3D points by regular parametric curves and their fast and efficient evaluation for a good resolution of rendering. For the purpose I have used a parallel environment using a multiprocessor cluster architecture. The efficiency of the used method is good, mainly reducing the number of floating-points computations by caching the numerical values of some line-parameter's powers, and reducing the necessity of communication among processes. This work has been developed for the Research and Development Department of my company for planning advanced customized models of industrial burners.

math.NA↗
arXiv2004

Cluster computing performances using virtual processors and mathematical software

In this paper I describe some results on the use of virtual processors technology for parallelize some SPMD computational programs in a cluster environment. The tested technology is the INTEL Hyper Threading on real processors, and the programs are MATLAB 6.5 Release 13 scripts for floating points computation. By the use of this technology, I tested that a cluster can run with benefit a number of concurrent processes double the amount of physical processors. The conclusions of the work concern on the utility and limits of the used approach. The main result is that using virtual processors is a good technique for improving parallel programs not only for memory-based computations, but in the case of massive disk-storage operations too.

cs.DC↗
arXiv2003

Using virtual processors for SPMD parallel programs

In this paper I describe some results on the use of virtual processors technology for parallelize some SPMD computational programs. The tested technology is the INTEL Hyper Threading on real processors, and the programs are MATLAB scripts for floating points computation. The conclusions of the work concern on the utility and limits of the used approach. The main result is that using virtual processors is a good technique for improving parallel programs not only for memory-based computations, but in the case of massive disk-storage operations too.

cs.DC↗
arXiv2003

Poster on MPI application in Computational Fluid Dynamics

Poster-presentation of the paper "Message Passing Fluids: molecules as processes in parallel computational fluids" held at "EURO PVMMPI 2003" Congress; the paper is on the proceedings "Recent Advances in Parallel Virtual Machine and Message Passing Interface", 10th European PVM/MPI User's Group Meeting, LNCS 2840, Springer-Verlag, Dongarra-Laforenza-Orlando editors, pp. 550-554.

cs.DC↗
arXiv2003

Message Passing Fluids: molecules as processes in parallel computational fluids

In this paper we present the concept of MPF, Message Passing Fluid, an abstract fluid where the molecules move by mean of the informations that they exchange each other, on the basis of rules and methods of a generalized Cellular Automaton. The model is intended for its simulation by mean of message passing libraries on the field of parallel computing. We present a critical analysis of the necessary computational effort in a possible implementation of such an object.

physics.flu-dyn↗
arXiv2003

A first approach for a possible cellular automaton model of fluids dynamics

In this paper I present a first attempt for a possible description of fluids dynamics by mean of a cellular automata technique. With the use of simple and elementary rules, based on random behaviour either, the model permits to obtain the evolution in time for a two-dimensional grid, where one molecule of the material fluid can ideally place itself on a single geometric square. By mean of computational simulations, some realistic effects, here showed by use of digital pictures, have been obtained. In a subsequent step of this work I think to use a parallel program for a high performances computational simulation, for increasing the degree of realism of the digital rendering by mean of a three-dimensional grid too. For the execution of the simulations, numerical methods of resolution for differential equations have not been used.

cs.CC↗
arXiv2002

Use of openMosix for parallel I/O balancing on storage in Linux cluster

In this paper I present some experiences made in the matter of I/O for Linux Clustering. In particular is illustrated the use of the package openMosix, a balancer of workload for processes running in a cluster of nodes. I describe some tests for balancing the load of I/O storage massive processes in a cluster with four components. This work is been written for the proceedings of the workshop Linux cluster: the openMosix approach held at CINECA, Bologna, Italy, on 28 november 2002.

cs.DC↗
arXiv2002

A generalization of Amdahl's law and relative conditions of parallelism

In this work I present a generalization of Amdahl's law on the limits of a parallel implementation with many processors. In particular I establish some mathematical relations involving the number of processors and the dimension of the treated problem, and with these conditions I define, on the ground of the reachable speedup, some classes of parallelism for the implementations. I also derive a condition for obtaining superlinear speedup. The used mathematical technics are those of differential calculus. I describe some examples from classical problems offered by the specialized literature on the subject.

cs.DC↗