loop index????

GAMS
1

Hi All,
I need some help through this Error "Loop controlling index…"Error 50.
I can not remove this error, It means loop index should not be used in Equation???
My codes is as following :

SETS s /1119/;
.
.
.
EQUATIONS
const_w(s)
Objective;
.
.
.
.
MODEL Problem /All/;
PARAMETER WW(s) /11 200,12 400,13 60,14 800,15 100,16 120,7 1400,18 160,19 1800/;
Parameter res(,s);
PARAMETER sayeh(s);
LOOP(s,
W=WW(s);
SOLVE Problem USING NLP MAXIMIZING Obj;
**** $50,256
.
.
.
.);

Thank you.
MANa

–
To unsubscribe from this group and stop receiving emails from it, send an email to gamsworld+unsubscribe@googlegroups.com.
To post to this group, send email to gamsworld@googlegroups.com.
Visit this group at http://groups.google.com/group/gamsworld.
For more options, visit https://groups.google.com/groups/opt_out.

\

2

Hi Mana

Le dimanche 21 juillet 2013 18:35:44 UTC+2, Mana_gms a écrit :

Hi All,
I need some help through this Error "Loop controlling index…"Error 50.
I can not remove this error, It means loop index should not be used in Equation???



Yes, that’s exactly what it means.

Out of two things, one is possible :

  • either you want to solve your model for each elements of the set S, and for each solve you just need one constraint CONST_W, the coefficients of which depend on the current set element S : in this case, you have to define a constraint CONST_W which is not indexed on S, but you adapt its coefficients in the loop, just like W = WW(s) ;

  • or you need, for each solve in the loop, to have all nine constraints over each possible value of S. Then you need to use aliases : define your constraint over S, as is. But then, before the loop, use :

ALIAS (S,S2) ;
LOOP(S2,
W = WW(S2);
SOLVE Problem…

which will avoid using the same index in the controlling loop and in the constraint definition.
Hope this helps,
cheers
dax

–
To unsubscribe from this group and stop receiving emails from it, send an email to gamsworld+unsubscribe@googlegroups.com.
To post to this group, send email to gamsworld@googlegroups.com.
Visit this group at http://groups.google.com/group/gamsworld.
For more options, visit https://groups.google.com/groups/opt_out.

\

3

Hi Dax,
Thank you for your help. It was really useful.
Mana

On Sunday, July 21, 2013 9:05:44 PM UTC+4:30, Mana_gms wrote:

Hi All,
I need some help through this Error "Loop controlling index…"Error 50.
I can not remove this error, It means loop index should not be used in Equation???
My codes is as following :

SETS s /1119/;
.
.
.
EQUATIONS
const_w(s)
Objective;
.
.
.
.
MODEL Problem /All/;
PARAMETER WW(s) /11 200,12 400,13 60,14 800,15 100,16 120,7 1400,18 160,19 1800/;
Parameter res(,s);
PARAMETER sayeh(s);
LOOP(s,
W=WW(s);
SOLVE Problem USING NLP MAXIMIZING Obj;
**** $50,256
.
.
.
.);

Thank you.
MANa

–
To unsubscribe from this group and stop receiving emails from it, send an email to gamsworld+unsubscribe@googlegroups.com.
To post to this group, send email to gamsworld@googlegroups.com.
Visit this group at http://groups.google.com/group/gamsworld.
For more options, visit https://groups.google.com/groups/opt_out.

\