Jean-Claude Charr

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This article presents JACEP2P-V2, a Java environment dedicated to designing parallel iterative asynchronous algorithms (with direct communications between nodes) and executing them on global computing architectures or distributed clusters composed by a large number of volatile heterogeneous distant computing nodes. This platform is fault tolerant,(More)
Dynamic Voltage Frequency Scaling (DVFS) can be applied to modern CPUs. This technique is usually used to reduce the energy consumed by a CPU while computing. Thus, decreasing the frequency reduces the power consumed by the CPU. However, it can also significantly affect the performance of the executed program if it is compute bound and if a low CPU(More)
Computing platforms are consuming more and more energy due to the increasing number of nodes composing them. To minimize the operating costs of these platforms many techniques have been used. Dynamic voltage and frequency scaling (DVFS) is one of them. It reduces the frequency of a CPU to lower its energy consumption. However, lowering the frequency of a(More)
This paper introduces a parallel algorithm to solve large stiff ODE systems in a geographically distant cluster environment. This algorithm is based on the coupling of the waveform relaxation concept and the CVODE algorithm. With respect to the standard PVODE algorithm, it allows to drastically reduce the number of messages exchanged between nodes. It is a(More)
This article presents an algorithm that performs a decentralized detection of the global convergence of parallel asynchronous iterative applications. This algorithm is fault tolerant. It runs a decentralized saving procedure which enables this algorithm, after a node’s crash, to replace the dead node by a new one which will continue the computing task from(More)
The issue addressed in this paper is how to build low-level hybrid cooperative optimization methods that combine a Genetic Algorithm (GA) with a Branch-and-Bound algorithm (B&B). The key challenge is to provide a common solution and search space coding and associated transformation operators enabling an efficient cooperation between the two algorithms.(More)
It is widely accepted that the asynchronous parallel methods are more suitable than the synchronous ones on a grid architecture. Indeed, they outperform the synchronous methods, because they overlap the communications of the synchronous methods with computations. However, they also usually execute more iterations than the synchronous ones and thus consume(More)
In recent years, green computing has become an important topic in the supercomputing research domain. However, the computing platforms are still consuming more and more energy due to the increasing number of nodes composing them. To minimize the operating costs of these platforms many techniques have been used. Dynamic voltage and frequency scaling (DVFS)(More)
This paper presents a new online frequency selecting algorithm for asynchronous parallel methods running over grids. It selects a vector of frequencies that gives the best tradeoff between energy consumption and performance. It also has a very small overhead and works without training and profiling. New energy and performance models are used in this(More)
This paper presents new adaptations of two methods that solve large differential equations systems, to the grid context. The first method is based on the Multisplitting concept and the second on the Waveform Relaxation concept. Their adaptations are implemented according to the asynchronous iteration model which is well suited to volatile architectures that(More)