Random BuiltIn Function in Stella

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Random BuiltIn Function in Stella
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RANDOM(ltmingt, ltmaxgt, ltseedgt) The RANDOM builtin
generates a series of uniformly distributed
random numbers between min and max. RANDOM
samples a new random number in each iteration of
a model run. If you wish to replicate the
stream of random numbers, specify seed as an
integer between 1 and 32767. To replicate a
simulation, all entities that use statistical
functions must have seeds specified. Each entity
using a statistical function should use a
separate seed value.
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Examples RANDOM(0,1) creates a non-replicable
uniformly distributed stream of numbers between 0
and 1. RANDOM(0,1,147) creates a replicable
uniformly distributed stream of numbers between 0
and 1. RANDOM(0,10,12) gives a replicable
uniformly distributed stream of numbers between 0
and 10. RANDOM(10,13,12) gives a replicable
uniformly distributed stream of numbers between
10 and 13.
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Build the flower model of Chapter 6 to reproduce
the output shown on the next page. Or get it
from http//www.atmosedu.com/WSU/esrp310-550/PP/F
lowers.STM
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Now add a new converter for temperature and
connect it To the intrinsic growth rate. In the
original model the intrinsic growth rate was
fixed at 1.0. Here well let Temperature be
Random (20,30,999) and intrinsic
growth rate temperature/25.0 We added the seed
here so all simulations will look the same.
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Paste your resulting graphs of Flower area,
growth, and decay here.
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Try letting Temperature be Random (15,35,999)
and intrinsic growth rate
temperature/25.0 What do you expect to be
different for this new simulation? ANSWER
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Paste your resulting graphs of Flower area,
growth, and decay here.
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NORMAL(ltmeangt,ltstdgt, ltseedgt) The NORMAL builtin
generates a series of normally distributed random
numbers with a specified mean and std (standard
deviation). NORMAL samples a new random number
in each iteration of a simulation. If you wish
to replicate the stream of random numbers,
specify seed as an integer between 1 and 32767.
To replicate a simulation, all entities that use
statistical functions must have seeds specified.
Each entity using a statistical function should
use a separate seed value.
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Examples NORMAL(0,1) gives a non-replicable
normally distributed stream of numbers (mean0,
standard deviation1) NORMAL(0,1,147) gives a
replicable normally distributed stream of numbers
(mean0, standard deviation1) NORMAL(5,1,12)
gives a replicable normally distributed stream of
numbers (mean5, standard deviation1) NORMAL(10,
5,102) gives a replicable normally distributed
stream of numbers (mean10, standard deviation5)
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Now let Temperature be Normal (25,5,999)
and intrinsic growth rate
temperature/25.0 We added the seed here so all
simulations will look the same and make it easier
for your instructor to see if you got things set
correctly.
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Paste your resulting graphs of Flower area,
growth, and decay here.
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Now let Temperature be Normal (25,10,999)
and intrinsic growth rate
temperature/25.0 What do you expect to be
different for this new simulation? ANSWER
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Paste your resulting graphs of Flower area,
growth, and decay here.
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Download the 3rd version of the MonoLake
Model. http//www.atmosedu.com/WSU/esrp310-550/mon
oLake/MonoLake3.STM This has a comparitive graph
set for volume in the lake.
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Run the model once to get a graph of water in
the lake with a fixed export of 100. Now run
with export set to Normal (100,50,999) . Run
this 7 times.(dont expect big things here) Now
run with export set to Normal (100,50) . Run
this 7 times
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Paste your resulting graphs of Flower area,
growth, and decay here.
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Comment on the advantages and disadvantage of the
seed