JAMS Pre Processing Failed - Solver Error

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ujrai1
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JAMS Pre Processing Failed - Solver Error

Post by ujrai1 » 3 months ago

Hi,
I am experiencing a solver problem at the execution of GAMS file. I am trying to implement a two stage problem using stochastic programming similar to News Vendor Problem using emf (Extended Mathematical programming) solver. It comes up as
***status: Normal Completion
without any Erros but also having these two messages in .lst file
*** EMP syntax error: key expected: is neither a variable nor an equation: randvar (item 1 on line 2)
***
*** JAMS Pre processing failed
***

I have tried changing syntax but the issue remains and though its a Normal completion but it doesn't solve the uncertainity issue in the problem.
Can anyone please elaborate what could be the issue. I have attached my GAMS file.

•Capacity of 4th generator needs to be a decision variable.
•Capacity of 4th generator is stage1, as is the objective function.
•Cost of 5th generator (system buy price) is a random variable.
Attachments
gen4.gms
(2.15 KiB) Downloaded 13 times

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Renger
Posts: 187
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Re: JAMS Pre Processing Failed - Solver Error

Post by Renger » 3 months ago

Hi
I ran your model on my notebook (Gams 24.9.1 with CPLEX) and it runs fine. Here is the essential output:

Code: Select all

EXECUTION TIME       =        0.172 SECONDS      4 MB  24.9.1 r63795 WEX-WEI
GAMS 24.9.1  r63795 Released Aug 30, 2017 WEX-WEI x86 64bit/MS Windows 07/14/18 16:37:20 Page 5
G e n e r a l   A l g e b r a i c   M o d e l i n g   S y s t e m
Solution Report     SOLVE gen4 Using EMP From line 64


               S O L V E      S U M M A R Y

     MODEL   gen4                OBJECTIVE  obj
     TYPE    EMP                 DIRECTION  MINIMIZE
     SOLVER  JAMS                FROM LINE  64

**** SOLVER STATUS     1 Normal Completion         
**** MODEL STATUS      1 Optimal                   
**** OBJECTIVE VALUE       9919800000.0000

 RESOURCE USAGE, LIMIT          0.079      1000.000
 ITERATION COUNT, LIMIT         0    2000000000
 EVALUATION ERRORS              0             0

JAMS 1.0         24.9.1 r63795 Released Aug 30, 2017 WEI x86 64bit/MS Windows 

JAMS - Solver for Extended Mathematical Programs (EMP)
------------------------------------------------------

*** Problems reading JAMS info file: c:\Users\renge\Downloads\225a\empinfo.dat

---
--- No reformulations requested
--- Generating unchanged scalar model
---
--- The model c:\Users\renge\Downloads\225a\emp.dat will be solved by GAMS
---
--- Returning from GAMS step

IBM ILOG CPLEX   24.9.1 r63795 Released Aug 30, 2017 WEI x86 64bit/MS Windows 
Cplex 12.7.1.0

Space for names approximately 0.00 Mb
Use option 'names no' to turn use of names off
LP status(1): optimal
Cplex Time: 0.02sec (det. 0.01 ticks)
Optimal solution found.
Objective :  9919800000.000000

---
--- Equations skipped = 0  Equations added = 0
--- Variables skipped = 0  Variables added = 0
---
What version of Gams and which solver are you using?
Cheers
Renger

ujrai1
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Re: JAMS Pre Processing Failed - Solver Error

Post by ujrai1 » 3 months ago

Hi Renger,

Thanks for your reply. I am using;

GAMSIDE build 63619 / 63795
GAMS Release 24.9.1 r63795 WEX-WEI x86 64bit/MS Windows
Release Date Released Aug 30, 2017
License Date Aug 30, 2017

Yes, it gives me a deterministic model with emp as I have put the 2nd stage in comments in .gms file; If you remove the following asterisks in the main file and try to solve it with 2 stage stochastic programming, it gives an error and I am unable to sort it out.

*file emp / '%emp.info%' /; put emp '* problem %gams.i%'/;
*$onput
*randvar c5 discrete 0.7 60
* 0.2 50
* 0.1 40
*stage 2 g1_ut g2_ut g3_ut g5_ut c5
*stage 2 demand_satisfaction gen1_utilisation gen2_utilisation gen3_utilisation gen4_utilisation gen5_utilisation
*$offput
*putclose emp;

Thanks

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