LIGHTWEIGHT STRUCTURES in CIVIL ENGINEERINGINTERNATIONAL SEMINAR of IASS POLISH CHAPTER

Organized by Polish Chapter ofInternational Association for Shell and Spatial Structures

Warsaw-Częstochowa, 3 December, 2004

OVERLOADING OF OPERATORS IN FEMA SYSTEM

W. PRZYBYŁO 1 and M. MAŹNIEWSKI 2

1Professor, Częstochowa University of Technology, ul. Akademicka 3, 42-200 Częstochowa, POLAND

2PhD. student, Częstochowa University of Technology, ul. Akademicka 3, 42-200 Częstochowa, POLAND

FEM (Finite Elements Method)● Constructions are divided into many elements

● Elements are described with matrices

● Hypermatrix - matrix of matrices

● Problems associated with matrices:

– high requirements of disk and memory space

– high requirements of computational power

– costly and time-consuming calculations

Characteristics of matrix operations

● Problems' solutions are constructed as a set of subtasks

● Subtasks are executed one by another

● Some subtasks are repeated many times with different data-sets

● Some subtasks are independent one of another● Subtasks can be executed simultaneously

Parallelization of multiplying matrices

Comparison of computer systems● Single computer – one CPU● Symetric Multiprocessor(SMP)● Parallel computer

– many processors in one box– one processor – one task

● Clusters – set of computers jointed with network– Saving money by using owned hardware– Big computational power with low cost– Easy enlarging– Reliable calculations– Fail-safe system

Speeding-up calculations

● Simultaneous subtasks' execution

● Computer programs' parallelization

● Building clustered systems

● Requirements:

– Synchronization of data– Interprocess communication– Network communication

Modelling algorithms into computer programs

● Algorithm – description of problem solution

● Algorithms are constructed with cooperation of specialists

● Computer program – representation of algorithm

– different syntax of programming languages

– Only programmers understand source code

– Mathematic operations replaced with programming operations

Overloading of operators

● Arithmetic operators – works only with basic data-types(char, integer value, real value...)

● Defining own data-types – Objective Programming

● Matrix operations– Definition of object: MATRIX

● Overloading operators – allowing them work with user-defined data-types

● Problems with matrices operations– Large matrices need large disk and memory spaces– Assignment of matrices – copying one matrix to

another

Overloading of operators cont.● Classic mode

– a:=1, b:= 2 – integer values

– c := a + b, c = 3 – integer value

● Overloading operators

– A – matrix, dimension: n x n

– B – matrix, dimension: n x n

– C : = A + B - matrix, dimension n x n

– D : = A * B – matrix, dimension n x n

FEMA System

● Designed for matrices and hypermatrices operations

● Modular system for modular operations(parallelization enabled)

● Maximum dimension of data sets, minimum time of processing

Proposed approach

● Overloading matrix operations● Replacing copying of matrices – with commands

from FEMA system● Dividing task into subtasks● Writing steering files for every subtask● Sending steering files to nodes of clusters● Processing calculations in professional

system(FEMA)● Aggregation of calculations' results

Example

● Adding matrices:– in source code: C = A + B– in result : PHAH

ABC

● Multiplying matrices:– in source code: C = A * B– in result : PHMH

ABC

Appendix: Parallel example● Steering file is read by master-program

● Worker-program is invoked

● Master-program sends steering file to worker

● Worker-program writes steering file to hard-disk

● Worker-program invokes FEMA system

● FEMA system read task-definition and input data

● FEMA system executes operations and writes results to hard-disk

Steering file example (fema.CIN)

● DDEX● DEX-BAT● DDEX7● 2● 3● Y● Y● N● N● END● END

Console output● [1:t40005] Master process..262149..[ bind and ready to distribute tasks ]..● [1:t40005] Master [262149]..Checking steering-file [/tmp/fema.CIN]

structure...OK● [1:t40005] Worker-process..ID...262150: [ ready to execute tasks ]● [1:t40005] Process: [262149] ready to send steering file..● [1:t40006] Process: [262150] ready to get steering file..● [1:t40005] [262149]..We've read: ● [1:t40005] DDEX● [1:t40005] DEX-BAT● [1:t40005] DDEX7● [1:t40005] 2● [1:t40005] 3● [1:t40005] Y● [1:t40005] Y● [1:t40005] N● [1:t40005] N● [1:t40005] END● [1:t40005] END● [1:t40005] END ● [1:t40005] Process [262149]..sending steering file to worker(s)..● [1:t40006] Process: [262150] retrieved cmd:● [1:t40006] ..DDEX● [1:t40006] DEX-BAT● [1:t40006] DDEX7● [1:t40006] 2● [1:t40006] 3● [1:t40006] Y● [1:t40006] Y● [1:t40006] N● [1:t40006] N

● [1:t40006] END● [1:t40006] END● [1:t40006] END● [1:t40005] Process: [262149] - retrieved confirmation..● [1:t40005] Process: [262149] exiting..● [1:t40005] EOF● [1:t40006] ....confirmation sent to master..● [1:t40006] Process: [262150]..Attempting to write steering file

[/home/pvm3/bin/LINUX/FEMA/task/fema.CIN]..● [1:t40006] Process: [262150] - [ OK ] file has been written● [1:t40006] Process: [262150]..Attempting to run FEMA system..● [1:t40006] Process: [262150]..checking for task-definition file..● [1:t40006] Process: [262150] - [ OK ] task-definition file is proper..● [1:t40006] Process: [262150]..running FEMA system..● [1:t40006] sh: CLS: command not found● [1:t40006] sh: PAUSE: command not found● [1:t40006] sh: CLS: command not found● [1:t40006] sh: CLS: command not found● [1:t40006] sh: CLS: command not found● [1:t40006]

[34;1m********************************************************************************

● [1:t40006] WELCOME TO FEMA DATABASE MADE BY FEMA ENGINEERING LTD● [1:t40006] YOU HAVE SELECTED /home/pvm3/bin/LINUX/f88.exe,● [1:t40006] WITH /home/pvm3/bin/LINUX/FEMA/task/fema.INP AS ARGUMENT● [1:t40006]

********************************************************************************

● [1:t40006] [0m****************************************************************************

● [1:t40006] EOF