Hello,
I try to optimize a variable which is subject to time by using tomfid's following advice:
"TimeVec : (t1-t11)
IndicatedHiring[TimeVec] = 1,3,2,5,2, ...
Hiring = VECTOR LOOKUP(IndicatedHiring[t1],time,INITIAL TIME,FINAL TIME,0)
You then optimize to find the points of IndicatedHiring[TimeVec]."
I get an error message saying "No usable constant name.". What does it mean, why do I get it and what should I do?
Thanks for your help.
Optimization subject to TIME/ Time as subscript?
Re: Optimization subject to TIME/ Time as subscript?
We'd have to see your optimization control files (vpd & voc). I'd guess that you have a parameter in your voc that is not a constant.
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Re: Optimization subject to TIME/ Time as subscript?
Hello,
vpd & voc files are attached. I can also send you my model by e-mail.
vpd & voc files are attached. I can also send you my model by e-mail.
- Attachments
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- EXP Model V3.vpd
- (21 Bytes) Downloaded 169 times
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- EXP Model V3.voc
- (297 Bytes) Downloaded 166 times
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Re: Optimization subject to TIME/ Time as subscript?
The VOC (Vensim optimization control) only has one constant listed (IPABGG). You need to modify this to include the IndicatedHiring[TimeVec] constant as well.
This can be done via the opimization wizard (the "Choose optimization" part of the 2nd dialog, the one with the optimizer, random type etc settings).
This can be done via the opimization wizard (the "Choose optimization" part of the 2nd dialog, the one with the optimizer, random type etc settings).
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Re: Optimization subject to TIME/ Time as subscript?
The file should look something like
Code: Select all
:OPTIMIZER=Powell
:SENSITIVITY=Off
:MULTIPLE_START=RRandom
:RANDOM_NUMER=Default
:OUTPUT_LEVEL=On
:TRACE=Off
:MAX_ITERATIONS=1000
:RESTART_MAX=0
:PASS_LIMIT=2
:FRACTIONAL_TOLERANCE=0.01
:TOLERANCE_MULTIPLIER=21
:ABSOLUTE_TOLERANCE=1
:SCALE_ABSOLUTE=1
:VECTOR_POINTS=25
0<=IndicatedHiring[t1]<=1
0<=IndicatedHiring[t2]<=1
0<=IndicatedHiring[t3]<=1
0<=IndicatedHiring[t4]<=1
0<=IndicatedHiring[t5]<=1
0<=IndicatedHiring[t6]<=1
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