GAMS World Forum

Posted: **Wed Feb 15, 2023 11:54 pm**

Dear friends,

I have a multidimensional parameter with 4 sets and 1 value into a gdx file.

I would like to know how many rows do I have per each set r1,p1,r2 or p2.

The problem is that the file is too large and I cannot open the gdxviewer, and I don't know the different elements that I have in each set.

So, I'm looking for this kind of information (in the image is the sample):

for r1: a1 2, a2 1
for p1: xa0 2, xa2 1
for r2: a2 2, a1 1
for p2: yt5 1, yt3 1, yt1 1.

Maybe you can help me.

Thank you and all the best,

: table with elements; image.png (2.7 KiB) Viewed 3648 times

Posted: **Thu Feb 16, 2023 7:49 am**

This is easily achieved by the projection operator accessible via the option statement. See https://www.gams.com/latest/docs/UG_Opt ... ggregation for details. Here is the code for your example:

Code: Select all

set r1,p1,r2,p2;
parameter d(r1<,p1<,r2<,p2<) /
a1.xa0.a2.yt5 6
a1.xa0.a2.yt3 5
a2.xa2.a1.yt1 7
/;

parameter cnt_r1(r1), cnt_p1(p1), cnt_r2(r2), cnt_p2(p2);

option cnt_r1<d, cnt_p1<d, cnt_r2<d, cnt_p2<d;

display cnt_r1, cnt_p1, cnt_r2, cnt_p2;

which results in the following display:

Code: Select all

----     12 PARAMETER cnt_r1  
a1 2.000,    a2 1.000

----     12 PARAMETER cnt_p1  
xa0 2.000,    xa2 1.000

----     12 PARAMETER cnt_r2  
a1 1.000,    a2 2.000

----     12 PARAMETER cnt_p2  
yt5 1.000,    yt3 1.000,    yt1 1.000

-Michael

GAMS World Forum

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