Works well, thank you very much Renger!

Regards,

Anna

On Wednesday, October 10, 2012 8:58:29 PM UTC+2, Renger van Nieuwkoop wrote:

Hi Anna

Just split the sum in 3 spearate sumes and then you can use the sign on the indices
\
\
\
CHANGE(I).. SUM(J((ord(J)-1) ne BETA(I)), sum(K$((ord(K)-1) ne GAMMA(I)), sum(L ,Y(I,J,K,L))))=L= W(I);

Cheers

Renger

From: gams...@googlegroups.com [mailto:gams...@googlegroups.com] On Behalf Of Anna

Sent: Wednesday, October 10, 2012 6:30 PM

To: gams...@googlegroups.com

Subject: Re: CONDITIONAL EQUATION. INDEX RESTRICTION

Hello,

I have a similar problem as described above. I would like to exclude some indices (defined as parameters) from the summation within a conditional equation. I tried something like below, but it didn’t work.

PARAMETERS

BETA(I)

GAMMA(I) // define the indices that should be excluded from summation for every t

VARIABLES //binary

Y(I,J,K,L)

W(I)

CHANGE(I)… SUM((J$(J ne BETA(I)), K$(K ne GAMMA(I)), L) ,Y(I,J,K,L))=L= W(I);

neither this nor

CHANGE(I)… SUM((J$((ord(J)-1) ne BETA(I)), K$((ord(K)-1) ne GAMMA(I)), L) ,Y(I,J,K,L))=L= W(I);

worked. It returns error 148 (dimension different) and apparently, there’s also a parenthesis ‘)’ missing but all of them are paired.

Is a potential cause that the excluding indices are defined as parameters, not sets? I would be grateful for any hints on how to work around this.

Thanks!

Anna

On Wednesday, May 11, 2011 4:21:00 AM UTC+2, AC wrote:

Or you could try:

GENERATION(i)$(NOT SameAs(i,“N1”))…

On May 9, 8:50 pm, Pedro wrote:

Hello,

I have a doubt with GAMS, I hope somebody can help me. I’ve got a

equation defined for all values of an index and I want to make an

exception with one of the particular values that the index can have.

Example:

set i /N1*N6/

GENERATION(i)$(i ne “N1”)…

So I want to define GENERATION for all values of the index i but “N1”.

Thank you so much for your help

Pedro

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