Defining equation with logical condition on index

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1

Hi everyone,

I’m new to GAMS and since last few days I’m trying code an equation but finding it difficult to do so. In the equation j is an element which belong to intersection of 2 multidimensional sets i.e. JP(jp) and JS(js). Below I’m attaching an image of the equation.
forum_doubt_1.JPG
Also, the code that I have developed for the above equation is as follows:

Constraints8(s,p)..       sum(j,Y(s,j,p)) =e= 1;

Please help if you know how to code this thing. It would be really helpful. Thanks.

2

You can create multidimensional sets jp(j, p) and js(j, s). Find more information on multidimensional sets here: https://www.gams.com/latest/docs/UG_SetDefinition.html#UG_SetDefinition_Multi-dimensionalSets

set
jp /#j.#p/
js /#j.#s/
;

You can then write your constraint with if condition

constraints8(s, p).. sum(j $(jp(j, p) and js(j, s)), Y(s, j, p)) =e= 1;

Not sure if it is relevant, but I also note that your equation is defined over p^in _p. If this is by any chance a subset of set P, you can define it as
set
p_in(p);

and then assign relevant elements to it.
Hope this helps!

  • Atharv
3

Hi Athrav,

Thanks a lot for your suggestions, it worked. Also, I forgot to mention that P^in(P) is a subset of P but you have already assumed it correctly. Thank you for helping me out. :slight_smile: