6 research outputs found
Power Saving Experiments for Large Scale Global Optimization
Green computing, an emerging ïŹeld of research that seeks to reduce excess power consumption in high performance computing (HPC), is gaining popularity among researchers. Research in this ïŹeld often relies on simulation or only uses a small cluster, typically 8 or 16 nodes, because of the lack of hardware support. In contrast, System G at Virginia Tech is a 2592 processor supercomputer equipped with power aware components suitable for large scale green computing research. DIRECT is a deterministic global optimization algorithm, implemented in the mathematical software package VTDIRECT95. This paper explores the potential energy savings for the parallel implementation of DIRECT, called pVTdirect, when used with a large scale computational biology application, parameter estimation for a budding yeast cell cycle model, on System G. Two power aware approaches for pVTdirect are developed and compared against the CPUSPEED power saving system tool. The results show that knowledge of the parallel workload of the underlying application is beneficial for power management
Adjusting process count on demand for petascale global optimizationâ
There are many challenges that need to be met before efficient and reliable computation at the
petascale is possible. Many scientific and engineering codes running at the petascale are likely to
be memory intensive, which makes thrashing a serious problem for many petascale applications.
One way to overcome this challenge is to use a dynamic number of processes, so that the total
amount of memory available for the computation can be increased on demand. This paper
describes modifications made to the massively parallel global optimization code pVTdirect in
order to allow for a dynamic number of processes. In particular, the modified version of the
code monitors memory use and spawns new processes if the amount of available memory is
determined to be insufficient. The primary design challenges are discussed, and performance
results are presented and analyzed
Parallel Deterministic and Stochastic Global Minimization of Functions with Very Many Minima
The optimization of three problems with high dimensionality and many local minima are investigated
under five different optimization algorithms: DIRECT, simulated annealing, Spallâs SPSA algorithm, the KNITRO
package, and QNSTOP, a new algorithm developed at Indiana University
Filter-based DIRECT method for constrained global optimization
This paper presents a DIRECT-type method that uses a filter methodology to assure convergence to a feasible and optimal solution of nonsmooth and nonconvex constrained global optimization problems. The filter methodology aims to give priority to the selection of hyperrectangles with feasible center points, followed by those with infeasible and non-dominated center points and finally by those that have infeasible and dominated center points. The convergence properties of the algorithm are analyzed. Preliminary numerical experiments show that the proposed filter-based DIRECT algorithm gives competitive results when compared with other DIRECT-type methods.The authors would like to thank two anonymous referees and the Associate Editor for their
valuable comments and suggestions to improve the paper.
This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT
- Fundacžao para a CiĂȘncia e Tecnologia within the projects UID/CEC/00319/2013 and Ë
UID/MAT/00013/2013.info:eu-repo/semantics/publishedVersio