Trouble with $ operator in my model

GAMS
1

Any help with my problem would be greatly appreciated.

I have sets, variables, an equation, and other things which are irrelevant to this question

SETS J months /1*12/
I type /1,2/;

VARIABLES
X(I,J)
Y(I,J);

EQUATION
CONSCOND(J) conservation condition;

CONSCOND(J)… X(‘1’,J) + X(‘2’,J) + Y(‘2’,J-1) - Y(‘1’,J) - Y(‘2’,J) =E= 0;

My question is in regard to the equation. I want to limit the defined equations for J >= 2 so that CONSCOND(1) is not defined. From my reading, I thought that the following should work:

CONSCOND(J)$(J >= 2)… X(‘1’,J) + X(‘2’,J) + Y(‘2’,J-1) - Y(‘1’,J) - Y(‘2’,J) =E= 0;

I cannot get the $ operator to work for me in this way.

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2

Hi Bryan



j is a set and set elements are not numbers, just character strings. So if you want to use it as a number you can either use j.val (which, in case the j-elements are numerical values, changes the set element to a number) or you use ord(j) which gives you the order of the element in the set.



Hope this helps



Renger


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From: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] On Behalf Of Bryan Arguello
Sent: Donnerstag, 24. Oktober 2013 05:32
To: gamsworld@googlegroups.com
Subject: Trouble with $ operator in my model



Any help with my problem would be greatly appreciated.



I have sets, variables, an equation, and other things which are irrelevant to this question



SETS J months /1*12/

I type /1,2/;



VARIABLES

X(I,J)

Y(I,J);



EQUATION

CONSCOND(J) conservation condition;



CONSCOND(J)… X(‘1’,J) + X(‘2’,J) + Y(‘2’,J-1) - Y(‘1’,J) - Y(‘2’,J) =E= 0;



My question is in regard to the equation. I want to limit the defined equations for J >= 2 so that CONSCOND(1) is not defined. From my reading, I thought that the following should work:



CONSCOND(J)(J >= 2).. X('1',J) + X('2',J) + Y('2',J-1) - Y('1',J) - Y('2',J) =E= 0; \ \ \ I cannot get the operator to work for me in this way.


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