Implementation of the EARTH programming model on SMP clusters: a multi-threaded language and runtime system

2003 ◽  
Vol 15 (9) ◽  
pp. 821-844 ◽  
Author(s):  
G. Tremblay ◽  
C. J. Morrone ◽  
J. N. Amaral ◽  
G. R. Gao
2011 ◽  
Vol 19 (1) ◽  
pp. 47-62 ◽  
Author(s):  
David M. Kunzman ◽  
Laxmikant V. Kalé

Heterogeneous clusters that include accelerators have become more common in the realm of high performance computing because of the high GFlop/s rates such clusters are capable of achieving. However, heterogeneous clusters are typically considered hard to program as they usually require programmers to interleave architecture-specific code within application code. We have extended the Charm++ programming model and runtime system to support heterogeneous clusters (with host cores that differ in their architecture) that include accelerators. We are currently focusing on clusters that include commodity processors, Cell processors, and Larrabee devices. When our extensions are used to develop code, the resulting code is portable between various homogeneous and heterogeneous clusters that may or may not include accelerators. Using a simple example molecular dynamics (MD) code, we demonstrate our programming model extensions and runtime system modifications on a heterogeneous cluster comprised of Xeon and Cell processors. Even though there is no architecture-specific code in the example MD program, it is able to successfully make use of three core types, each with a different ISA (Xeon, PPE, SPE), three SIMD instruction extensions (SSE, AltiVec/VMX and the SPE's SIMD instructions), and two memory models (cache hierarchies and scratchpad memories) in a single execution. Our programming model extensions abstract away hardware complexities while our runtime system modifications automatically adjust application data to account for architectural differences between the various cores.


Author(s):  
Enric Tejedor ◽  
Yolanda Becerra ◽  
Guillem Alomar ◽  
Anna Queralt ◽  
Rosa M Badia ◽  
...  

The use of the Python programming language for scientific computing has been gaining momentum in the last years. The fact that it is compact and readable and its complete set of scientific libraries are two important characteristics that favour its adoption. Nevertheless, Python still lacks a solution for easily parallelizing generic scripts on distributed infrastructures, since the current alternatives mostly require the use of APIs for message passing or are restricted to embarrassingly parallel computations. In that sense, this paper presents PyCOMPSs, a framework that facilitates the development of parallel computational workflows in Python. In this approach, the user programs her script in a sequential fashion and decorates the functions to be run as asynchronous parallel tasks. A runtime system is in charge of exploiting the inherent concurrency of the script, detecting the data dependencies between tasks and spawning them to the available resources. Furthermore, we show how this programming model can be built on top of a Big Data storage architecture, where the data stored in the backend is abstracted and accessed from the application in the form of persistent objects.


Author(s):  
Ioannis Parnassos ◽  
Nikolaos Bellas ◽  
Nikolaos Katsaros ◽  
Nikolaos Patsiatzis ◽  
Athanasios Gkaras ◽  
...  

2020 ◽  
Vol 157 ◽  
pp. 04006
Author(s):  
Ruben Kazaryan ◽  
Peraskovya Andreeva ◽  
Natalya Galaeva

Purpose. Development of methods and models of economic efficiency of the integrated use of various modes of transport in the interests of ensuring national security of the state. Methods. System analysis, logical-mathematical modeling, systems theory, economic-visual modeling, research methods of operations, economic and mathematical methods. Results. The paper discusses the need for the application of economic and mathematical models in the design of transport construction (model of “moving the earth masses”, linear programming model, design of the “red line” on the longitudinal profile, dynamic programming model). Conclusion. The difficult stage of the transition of economic and mathematical analysis from the verbal description of the system process to the elemental base of the mathematical apparatus. Most research models of operations are designed for single criteria. Economic and mathematical modeling allows the effect of “private optimization”.


2015 ◽  
Vol 50 (8) ◽  
pp. 275-276 ◽  
Author(s):  
Vassilis Vassiliadis ◽  
Konstantinos Parasyris ◽  
Charalambos Chalios ◽  
Christos D. Antonopoulos ◽  
Spyros Lalis ◽  
...  

1966 ◽  
Vol 25 ◽  
pp. 373
Author(s):  
Y. Kozai

The motion of an artificial satellite around the Moon is much more complicated than that around the Earth, since the shape of the Moon is a triaxial ellipsoid and the effect of the Earth on the motion is very important even for a very close satellite.The differential equations of motion of the satellite are written in canonical form of three degrees of freedom with time depending Hamiltonian. By eliminating short-periodic terms depending on the mean longitude of the satellite and by assuming that the Earth is moving on the lunar equator, however, the equations are reduced to those of two degrees of freedom with an energy integral.Since the mean motion of the Earth around the Moon is more rapid than the secular motion of the argument of pericentre of the satellite by a factor of one order, the terms depending on the longitude of the Earth can be eliminated, and the degree of freedom is reduced to one.Then the motion can be discussed by drawing equi-energy curves in two-dimensional space. According to these figures satellites with high inclination have large possibilities of falling down to the lunar surface even if the initial eccentricities are very small.The principal properties of the motion are not changed even if plausible values ofJ3andJ4of the Moon are included.This paper has been published in Publ. astr. Soc.Japan15, 301, 1963.


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