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gams:counting_the_number_of_equations_generated_by_a_specific_constraint [2007/08/09 15:56]
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-====== Counting the Number of Equations generated by a specific Constraint ====== 
- 
-//Q: I wonder if there is a nice way to count the number of the equation that is is related to a specific constraint. For example, a gams expression that is:// 
- 
-    demand(j) ..   ​sum(i,​ x(i,​j)) ​ =g=  b(j) ;  
- 
-//How can I count the number of equation generated by that equation? Is there any suffix or index I can refer to?// 
- 
-If you use the limrow = 1 option, then the output of your gams model will include the first instance of every equation you have defined and include a message indicating the number of skipped rows also generated: 
-<​code>​ 
----- demand ​ =G=  satisfy demand at market j 
- 
-demand(new-york).. ​ x(seattle,​new-york) + x(san-diego,​new-york) =G= 325 ; 
-      
-      (LHS = 0, INFES = 325 ***) 
-      
-REMAINING 2 ENTRIES SKIPPED 
-</​code> ​ 
- 
-Thus the constraint ''​demand(j)''​ generates three equations. 
- 
-Another approach is to use the results of the ''​profile''​ option to get the number of generated equations. Below is an example, which writes the collected information of the trnsport model into a file ''​eq.txt'':​ 
-<​code>​ 
-$call '​gamslib trnsport'​ 
-option limrow=1,​limcol=0,​ profile=1; 
-$include trnsport.gms 
-*  get number of equations from profile 
-execute 'grep -i secs %system.ofile% |grep "​EQUATION"​ >​eq.txt'​ 
-</​code>​ 
-The last entry of each line in ''​eq.txt''​ tells you the number of generated equations: 
-<​code>​ 
-  74  execute 'grep -i secs C:​\temp\xxx\t2.lst |grep "​EQUATION"​ >​eq.txt'​ 
-----     61 EQUATION ​  ​cost ​         0.000     0.000 SECS      4 Mb      1 
-----     63 EQUATION ​  ​supply ​       0.000     0.000 SECS      4 Mb      2 
-----     65 EQUATION ​  ​demand ​       0.000     0.000 SECS      4 Mb      3 
-</​code>​ 
- 
- 
  
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