Lindo error in stochastic programming

Problems with modeling
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sidsharma
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Lindo error in stochastic programming

Post by sidsharma » 5 months ago

Hi experts,

I am new to stochastic programming and GAMS.

While executing the GAMS file for stochastic programming I got following errors through emp file.

**** SOLVER STATUS FILE LISTED BELOW
=C*** emp.info line 3: Cannot find random parameter "=" in model.
=C Hint: EMP keys like Chance, Stage, VaR, ... are not allowed as symbol name
s
=C*** Error processing empinfo file
=C*** Problem in getObjects
=C*** Failure calling solver: LINDO (rc=1)
**** SOLVER STATUS FILE LISTED ABOVE
I could not find any solution to the problem. Please help.

Attaching the source GAMS file.
Thanks.
Attachments
Untitled_10.gms
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Lutz
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Re: Lindo error in stochastic programming

Post by Lutz » 5 months ago

Hi,

I found a few (formatting) problems in your emp.info file:

- You missed a line break before the last line
- traffic_sc does not exist in the model, you should not mention it as stage 2 symbol
- You did not name the random variables in the loop, but put in some numbers instead

According to these problems, I did some small adjustments in the EMP Annotations part, which allowed to solve the model:

Code: Select all

* EMP Annotations
File emp / '%emp.info%' /; put emp '* problem %gams.i%'/;
*emp.nd=2;
loop(tra, put 'randvar' traffic_bw.tn(tra) 'poisson' 10 /)
$onput
stage 2  traffic_bw phi sc_availability1 sc_availability2
$offput
putclose emp;
I hope that helps,
Lutz

sidsharma
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Re: Lindo error in stochastic programming

Post by sidsharma » 5 months ago

Thanks a lot... :D :D

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