How to write a while loop in GAMS

Question

Can anyone help me with this problem please. I want to add to i one by one and put the amount of x(i) equal to 1 in each step, so i wrote it as below but it's not working

loop(i,
    x('0')=1;
    t('0')=1;
while(t>m,
      ord(i)=ord(i)+1;
      display i;
      x(i)=1;
      display x;
      t(i)=t(i-1) +1;
   );
 );

And by the way m is a variable which is calculated before this, in an equation.

score 1 · Answer 1 · edited Jan 07 '16 at 11:44

1

If m is a variable from a model that was solved before, you should check its level using the .l attribute:

...
while(t>m.l,
...

edited Jan 07 '16 at 11:44

Yu Hao

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answered Jan 07 '16 at 11:13

Lutz

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score 0 · Answer 2 · answered Nov 01 '15 at 21:09

Look at this page to have a better idea of how to make a while loop in GAMS. Also look at this code because it may help you:

root=minroot;
*find a sign switch
while(signswitch=0 and root le maxroot,
   root=root+inc;
   function_value2= a-b*root+c*sqr(root);
   if((sign(function_value1) ne sign(function_value2)
      and abs(function_value1) gt 0
      and abs(function_value2) gt tolerance),
         maxroot=root;
         signswitch=1
   else
      if(abs(function_value2) gt tolerance,
         function_value1=function_value2;
         minroot=root;);
      );
*  display 'inside',minroot,maxroot,function_value1,function_value2;
);

Thanks but my problem is the M which is a variable – Sepideh Gh Nov 03 '15 at 03:21 — Sepideh Gh, Nov 03 '15 at 03:21
Is it impossible to write a while loop based on a variable? – Sepideh Gh Nov 03 '15 at 15:04 — Sepideh Gh, Nov 03 '15 at 15:04

How to write a while loop in GAMS

2 Answers2