Echo print

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The first item contained within the LST file is the echo print.  The echo print is simply a numbered copy of the instructions GAMS received in the GMS input file.  For example, in the LST file segment immediately below is the portion associated with the GAMS instructions in optimize.gms.

 

   3  VARIABLES             Z;v

   4  POSITIVE VARIABLES    Xcorn ,    Xwheat , Xcotton;

   5  EQUATIONS     OBJ,  land ,  labor;

   6  OBJ..  Z =E= 109 * Xcorn + 90 * Xwheat + 115 * Xcotton;

   7  land..             Xcorn +      Xwheat +       Xcotton =L= 100;

   8  labor..          6*Xcorn +  4 * Xwheat +  8  * Xcotton =L= 500;

   9  MODEL farmPROBLEM /ALL/;

  10  SOLVE farmPROBLEM USING LP MAXIMIZING Z;

Notes:

•The echo print is of the same character for all three examples so I only include the optimize.gms LST file echo print here.
•The echo print can incorporate lines from other files if include files are present as covered in the Including External Files chapter.
•The echo print can be partially or fully suppressed as discussed in the Standard Output chapter.
•The numbered echo print often serves as an important reference guide because GAMS reports the line numbers in the LST file where solves or displays were located as well as a the position of any errors that have been encountered.