Parallel virtual machine

Geist, A., Beguelin, A., Dongarra, J., Jiang, W., Manchek, R., Sunderam, V. PVM Parallel Virtual Machine A Users Guide and Tutorial for Networked Parallel Computing. MIT Press, Cambridge, Massachusetts, 1994. 

We show in Figs. 2 and 3 the speed up for a Davidson iteration obtained with the PVM [17] ( Parallel Virtual Machine ) and PVMe [18] ( PVM enhanced ) message passing interfaces respectively. Speed-up factors are here relative to the sequential version of the program (n=l), and the theoretical mciximum has been defined according to the expression s n) — n — I appropriate to the used master/slave model. 

A. Geist, A. Beguelin, J. Dongarra, W. Jiang, R. Manchek and V. Sun-deram, Parallel Virtual Machine, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, available at http //www.netlib.org/pvm/. ... 

PVM Parallel virtual machine a message-passing library developed at Oak Ridge National Laboratory. 

A. Beguelin, J. Dongarra, A. Geist, R. Manchek, and V. Sunderam, Oak Ridge National Laboratory Technical Report, TM-11826, 1991. A User s Guide to PVM Parallel Virtual Machine. PVM is available by electronic mail and anonymous ftp from netlib ornl.gov. 

DM-MIMD MPP machines are undoubtedly the fastest-growing class in the family of supercomputers, although this type of machine is more difficult to deal with than shared-memory machines and processor-array machines. For shared-memory systems the data distribution is completely transparent to the user. This is quite different for DM-MIMD systems, where the user has to distribute the data over the processors, and also the data exchange between processors has to be performed explicitly. The initial reluctance to use DM-MIMD machines has decreased lately. This is partly due to the now-existing standards for communication software such as MPI (message passing interface) and PVM (parallel virtual machine) and is partly because, at least theoretically, this class of systems is able to outperform all other types of machines. 

Wylie B, Geimer M, Nicolai M, Probst M (2007) Recent advances in parallel virtual machine and message passing interface. In CappeUo F, Herault T, Dongarra J (eds) Springer, Berlin, pp 107-116... 

While true parallel and multi-processor computers use much faster connections than IP protocol lines for internal communication, it is possible to simulate such systems using the Internet. Some spectacular computational feats have been achieved by coupling thousands of Internet-connected computers and using their idle cycles for the factorization of large numbers or, closely related, for the cracking of encryption schemes. Libraries for the setup of virtual parallel computers and cooperating distributed systems such as PVM (parallel virtual machine ) are readily available. 

To accommodate the possible chemical reactions of the ongoing corrosion process, the calculated concentrations at c (t -i- At) (cfin Fig. 32.3) must be corrected according to the local thermodynamic equilibrium. For this purpose, the concentrations c (t + At) are transferred into a thermodynamic subroutine ThermoScript [10], which contains the commercial program ChemApp [11]. ChemApp is based on a numerical Gibbs energy minimization routine in combination with tailor-made databases [12]. In order to avoid excessive calculation times, the parallel-computing system PVM (parallel virtual machine) is used, i.e., ThermoScript distributes the individual... 

Ordo Session This attribute indicates if Hosts have been attacked sequentially or in parallel. To get this information, it suffices to look at packet timestamps. If the first packet sent to the second virtual machine is posterior to the last one sent to the first virtual machine, they have been attacked sequentially. In other cases, they have been attacked in parallel. 

A totally different approach respects the idea that a Virtual Reality application that has basically the same state of its domain objects will render the same scene, respectively. It is therefore sufficient to distribute the state of the domain objects to render the same scene. In a multi-screen environment, the camera on the virtual scene has to be adapted to the layout of your projection system. This is a very common approach and is followed more or less, e.g., by approaches such as ViSTA or NetJuggler [978]. It is called the master-slave, or mirrored application paradigm, as all slave nodes run the same application and all user input is distributed from the master node to the slave nodes. All input events are replayed in the slave nodes and as a consequence, for deterministic environments, the state of the domain objects is sjmchronized on all slave nodes which results in the same state for the visualization. The master machine, just like the client machine in the client-server approach, does all the user input dispatching, but as a contrast to the client-server model, a master machine can be part of the rendering environment. This is a consequence from the fact that all nodes in this setup merely must provide the same graphical and computational resources, as all calculate the application state in parallel. 

Memory requirement for an unstmctured CFD code such as Fluent is approximately 1 GB RAM per IM cells. Nowadays, a total RAM of the order of 5-10 GB is standard for a single off-the-shelf PC configuration, making it possible in principle to fit the entire simulation into such a machine. However, to obtain practical turnover times, a parallel computer platform would be needed to solve virtual mannequin problems. In the form of Beowulf Linux clusters, such systems are quite inexpensive nowadays and can be bought virtually off-the-shelf. The development of a reliable, full-scale virtual matmequin seems a very realistic and feasible goal for the next few years. 

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