A tool kit of C language functions that can be linked with SIMSCRIPT programs to provide the data communication primitives necessary for distributed simulation is presented. A test case is discussed and some timing data are presented. Additionally some metrics, developed to determine the applicability of the server model decomposition for particular simulations, are discussed

Maly, Kurt J.

Overstreet, C. Michael

Paterra, Frank

English

NASA Technical Reports Server

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Distributcd Silnulat;ioii, No Spccial Tools Required* 
F'ratik Pa tc r rn ,  C. Micliael Ovcrslrccl ,  a n d  K u r l  Maly 
March 30, I990 
A h t  rnc t 
In this papcr tlic atiLIiorR prcscnt. a toolkit of C language lunctiona 
-that can be linked with SlMSCRIPT program 16 provide the data 
cornmiinicntion prirnit.ivca ncccwary for distributed simrtlation. The 
aiitliors' tcsl CMC is discrisscd and aome liming d a h  are presented. 
Additioiially iornc rnctrica, clcvclopcd lo  determine the applicability 
of tlle server inodcl clcconipmition for particular ~irniilntionn, are dia- 
crlsscd. 
1 Why Distribute Simulations . 
Coinputct fiimitlations are oltcn compritationally intensive tasks requiring 
long runs i n  order to ohtain risclril results. T h e  runtime requirements o l  
a simulakion model can be a problem both (luring model development and 
validation and while pcrfortning production tuns of the simulation. 
T h e  developmcnt o l  computer models to simulate a real world objects 
is a well understood ptoblein and number o l  tools exist to aid the  model 
developer 111. Oftcn tiinca, the initial runs o l  a simiilation model provide 
more qricstions than answers and the focus of study is changed. This re- 
sulls in an cvolrttioaary proccaa for motlel development, with refinements 
directed at dinerent attribirtcs a~ tile object or i ts  environment becomes 
better unclcrstood. Often the coinplcxity o l  tlie model also increases during 
this process. 
As the model is evolving, many runs may be needed to better understand 
t h e  object and to verify the correctness of the simulation. The runtime 
requirements of complex models can greatly increase the  time heeded to 
'Thir work w m  rtippotkd in part by CIT rindcr p n t  INF-69-002-01, by NASA under 
grant NAG-1-908, nnd Stin Microsjskrns under RF596043. 
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https://ntrs.nasa.gov/search.jsp?R=19900012965 2020-03-19T23:15:33+00:00Z
2 Model Decoirq>ositioii 
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3 Distributed Siiniilat,ioii with Standard Tools 
4 Tllc Toolkit, 
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5 T i 11 1 i 11 g D at, a i l l  i ( 1 D c co 1 r i 11 ( 1s it io 1 I C o 1 is ide r a t io 1 i s  
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6 Example 
IX l l /min t ik  OS Ort l r r s  li(;'l* ' I ' l j O  MS'I' 
10,000 r,o 200 0.00-5 0.30 0 .002  
I O 0  IO0 0.0 IO 0.M) 0.0 13 
500 'LO 0.050 :1.00 0.06 I 
I ,000 IO 0 .  IO0 ri.00 0.  I 2  I 
5.000 2 0.500 :\o.oo 0.60 I 
100,000 5 0  2.000 0.005 0.03 0.ow 
IO0 I .ooo 0.0 I l l  0.06 0.0 I:\ 
500 200 0.050 o.:lo O.O(i I 
I .ooo IO0 0. I O 0  O.(iO 0. I2 I 
5.000 'Lo 0.500 :1.00 O.(iO I 
500,000 r10 IO.000 0.005 O.OO(i 0.01)2 
IO0 5.000 0.0 IO 0.0 I 'L 0.0 I 3 
500 I .000 0,050 O.O(i0 o..oc; I 
I .ooo 500 0. IO0 ( I .  1 2 1  0 .  I2 I 
5.000 I 0 0  0.rd)~I O.(iOO O.(iO I 
I ,000,000 rto 2(1.0(10 0.00.5 o.oo:{ 0.002 
IO0 I O.OO(1 0.0 1 1 )  O.OO(i 0.0 I :I 
5(JO 2.000 0.050 0.030 0.06 I 
I .ooo I .ooo 0. I O 0  O.Ofi0 0. I2 I 
r).ooo 2(10 0.500 0.:100 O.(iO I 
7 Conclusioii 
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Refer en ces 


Distributed simulation, no special tools required

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