Tunç Bahçecioğlu » 2009 http://www.tuncbahcecioglu.com carpe omnium Tue, 26 Oct 2010 13:43:06 +0000 en hourly 1 http://wordpress.org/?v=3.0.1 Optimum Design of High-Rise Steel Buildings using an Evolution Strategy Integrated Parallel Algorithm http://www.tuncbahcecioglu.com/posts/optimum-design-of-high-rise-steel-buildings-using-an-evolution-strategy-integrated-parallel-algorithm/ http://www.tuncbahcecioglu.com/posts/optimum-design-of-high-rise-steel-buildings-using-an-evolution-strategy-integrated-parallel-algorithm/#comments Fri, 09 Oct 2009 23:22:22 +0000 tunc http://www.tuncbahcecioglu.com/posts/optimum-design-of-high-rise-steel-buildings-using-an-evolution-strategy-integrated-parallel-algorithm/ Optimum Design of High-Rise Steel Buildings using an Evolution Strategy Integrated Parallel Algorithm
This paper was presented in CC2009, Madeira, Portugal
O. Hasançebi1, T. Bahçecioglu1, Ö. Kurç1 and M.P. Saka21Department of Civil Engineering, 2Department of Engineering Sciences,
Middle East Technical University, Ankara, Turkey

doi:10.4203/ccp.91.66

Keywords: structural optimization, metaheuristic search techniques, evolution strategy, parallel computing, high-rise steel buildings.

Summary

This study presents an evolution strategy integrated parallel solution algorithm for efficient size optimum design of large steel space frame structures, in particular high-rise steel buildings. An optimum design achieved for such systems is not of much practical value unless structural members are selected from a discrete list of ready sections according to strength, stability and serviceability requirements of a chosen code of practice. Besides, geometric compatibilities between beam and column members framing into each other at rigid joints have to be considered for practicality of the application. These points are observed in the solution algorithm developed such that the provisions of the Allowable Stress Design Code of the American Institute of Steel Construction (ASD-AISC [1]) are adopted for steel frames which are subject to vertical and horizontal loads, and standard wide flange hot-rolled sections are used to size the structural members. The algorithm has two novel attributes associated with the integrated optimization method and its parallel computing environment. It implements a very effective adaptive discrete evolution strategy method recently developed by Hasançebi [2]. The serial version of the solution algorithm, which allows for its implementation using a single processor, is first computerized using Borland Delphi source code. Next a master-slave configuration based parallel version of the algorithm is developed, where the sequential code is modified and reorganized with the advanced techniques of parallel processing to operate within a parallel computing system, which can be multiprocessors of a single computer or a cluster of computers connected via a local area network. The uniqueness of the parallel computing environment generated for the algorithm lies in the point that unlike FORTRAN and C++ programming languages, Delphi is not naturally supported by any MPI (Message Passing Interface) implementation. In order to implement MPI for the algorithm, special Pascal headers for MPICH2 [3] provided by the Lazarus Project [4] are revised according to the requirements of the algorithm.

The efficiency of the parallel algorithm in the optimum design of high-rise steel buildings is assessed using three examples. These examples are a 1040-member steel space frame with 60 member groups, a 3590-member steel space frame with 109 member groups and a 7648-member steel space frame with 198 member groups. The optimum designs are achieved for these frames using a cluster of computers with 32 processors in all. It has been shown that a maximum speedup ratio between 12.2 and 16.8 can been achieved for these examples. The performance of parallel computing system versus the number of processors employed is also examined in each example.

References

1 Manual of Steel Construction, “Allowable Stress Design”, 9th edition, AISC, American Institutes of Steel Construction, Inc, Chicago, Illinois, USA, 1989.
2 O. Hasançebi, “Discrete Approaches in Evolution Strategies Based Optimum Design of Steel Frames”, Structural Engineering and Mechanics, 26(2), 191-210, 2007.
3 MPICH2 Library, “High-Performance and Widely Portable Implementation of Massage Passing Interface (MPI) standard”, http://www.mcs.anl.gov/research/projects/mpich2, 2009.
4 Lazarus Project, “Visual Programming Environment for the Free Pascal Compiler”, http://www.lazarus.freepascal.org, 2009.

]]> http://www.tuncbahcecioglu.com/posts/optimum-design-of-high-rise-steel-buildings-using-an-evolution-strategy-integrated-parallel-algorithm/feed/ 0 A Comparative Study on Two Different Direct Parallel Solution Strategies for Large-Scale Problems http://www.tuncbahcecioglu.com/posts/a-comparative-study-on-two-different-direct-parallel-solution-strategies-for-large-scale-problems/ http://www.tuncbahcecioglu.com/posts/a-comparative-study-on-two-different-direct-parallel-solution-strategies-for-large-scale-problems/#comments Sun, 02 Aug 2009 02:46:21 +0000 tunc http://www.tuncbahcecioglu.com/posts/a-comparative-study-on-two-different-direct-parallel-solution-strategies-for-large-scale-problems/ This is my latest publication

A Comparative Study on Two Different Direct Parallel Solution Strategies for Large-Scale Problems

T. Bahcecioglu, S. Ozmen and O. Kurc

This paper was presented in PARENG2009 Pecs, Hungary.
doi:10.4203/ccp.90.40
Web Page

Civil-Comp Proceedings

ISSN 1759-3433

CCP: 90

PROCEEDINGS OF THE FIRST INTERNATIONAL CONFERENCE ON PARALLEL, DISTRIBUTED AND GRID COMPUTING FOR ENGINEERING

Edited by: B.H.V. Topping and P. Iványi
Paper 40

A Comparative Study on Two Different Direct Parallel Solution Strategies for Large-Scale Problems

T. Bahcecioglu, S. Ozmen and O. Kurc

Department of Civil Engineering, Middle East Technical University, Ankara, Turkey

Full Bibliographic Reference for this paper
T. Bahcecioglu, S. Ozmen, O. Kurc, "A Comparative Study on Two Different Direct Parallel Solution Strategies for Large-Scale Problems", in B.H.V. Topping, P. Iványi, (Editors), "Proceedings of the First International Conference on Parallel, Distributed and Grid Computing for Engineering", Civil-Comp Press, Stirlingshire, UK, Paper 40, 2009. doi:10.4203/ccp.90.40
Keywords: parallel solution, multi-frontal, substructure, large-scale, PC cluster.
Summary
Parallel solution methods are being implemented in various commercial finite element analysis programs as a consequence of having large-scale structural models and increased affordability and availability of parallel computing environments. The current research on the parallel solution methods based on direct solution mainly focuses on two different kinds of solution strategies: global and domain-by-domain. Global solution strategies focus on the efficient solution of the system of linear equations. They require the entire stiffness matrix to be assembled and distributed to the computers. The domain-by-domain strategies, on the other hand, perform partitioning at the structural level and as a result they parallelize not only the equation solution but also the stiffness matrix generation, assembly, element force and stress computations.

This paper presents a comparative study on two different direct parallel solution strategies for the linear solution of large scale finite element models: global and domain-by-domain. The global solution strategy was examined by utilizing the parallel multi-frontal equation solver, MUMPS [1], together with a finite element program. In a similar manner a substructure based parallel solution framework [2] was utilized for investigating the domain-by-domain strategy.

Various large-scale structural models were solved with both global and domain-by-domain solution strategies in order to illustrate the efficiencies and weaknesses of each solution strategy. The test runs were performed using Windows XP running, a homogeneous PC cluster connected with an ordinary 1 GBit network switch.

The test runs performed for this study indicate that the global solution strategy was more efficient and faster than the domain-by-domain strategy for symmetric and uniform structural models but its efficiency was decreased as the symmetry and uniformity of the models diminished. The performance of the domain-by-domain strategy improved in non-uniform models and produced competitive solution times when compared to the times of the global solution strategy.

References
1
P.R. Amestoy, I.S. Duff, J.-Y. L’Excellent, "Multifrontal parallel distributed symmetric and unsymmetric Solvers", Comput. Methods Appl. Engrg., 184, 501-520, 2000. doi:10.1016/S0045-7825(99)00242-X
2
O. Kurc, "Parallel Computing in Structural Engineering", VDM Verlag, Germany, 2008.
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