SolverStudio & GAMS


SolverStudio supports the commercial GAMS modelling environment which needs to be downloaded and installed by the user. Downloading and installing GAMS will give you access to a demo version (with limited capabilities) which can be upgraded to the full version by purchasing a license.

SolverStudio (in version 0.5 and later) supports solving GAMS models in the cloud using the online NEOS support generously provided by GAMS. (Note that GAMS does not need to be downloaded or installed to use this NEOS feature.) Other features include easily importing GAMS GDX files into Excel. Thanks to integrated GDX support, SolverStudio is also faster when processing large data sets.

We recommend users look at the GAMS examples included with SolverStudio to see how data and results should be passed between a GAMS model and the spreadsheet.

We gratefully acknowledge the assistance provided by GAMS in providing us with a license to support the development and testing of SolverStudio, and also allowing us to distribute the GAMS GDX DLL (gdxdclib.dll) with SolverStudio. (This DLL, which is included in the GAMS download, is documented here. This file contains proprietary code owned by GAMS.)

The SolverStudio download includes examples of GAMS formulations. The following is another example provided by GAMS that illustrates their language structure.

       I   canning plants   / SEATTLE, SAN-DIEGO /
       J   markets          / NEW-YORK, CHICAGO, TOPEKA / ;
       A(I)  capacity of plant i in cases
         /    SEATTLE     350
              SAN-DIEGO   600  /
       B(J)  demand at market j in cases
         /    NEW-YORK    325
              CHICAGO     300
              TOPEKA      275  / ;
  TABLE D(I,J)  distance in thousands of miles
                    NEW-YORK       CHICAGO      TOPEKA
      SEATTLE          2.5           1.7          1.8
      SAN-DIEGO        2.5           1.8          1.4  ;
  SCALAR F  freight in dollars per case per thousand miles  /90/ ;
  PARAMETER C(I,J)  transport cost in thousands of dollars per case ;
            C(I,J) = F * D(I,J) / 1000 ;
       X(I,J)  shipment quantities in cases
       Z       total transportation costs in thousands of dollars ;
       COST        define objective function
       SUPPLY(I)   observe supply limit at plant i
       DEMAND(J)   satisfy demand at market j ;
  COST ..        Z  =E=  SUM((I,J), C(I,J)*X(I,J)) ;
  SUPPLY(I) ..   SUM(J, X(I,J))  =L=  A(I) ;
  DEMAND(J) ..   SUM(I, X(I,J))  =G=  B(J) ;

One thought on “SolverStudio & GAMS

  1. You may find that SolverStudio (v 0.09.02 or earlier) is not working with NEOS. NEOS have recently tweaked their systems, and so you need to edit or and change all lines with “time.sleep(1)” into “time.sleep(5)”. This will be fixed in the next release. Andrew

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