How to write AMPL for this constraint?

[Vinh K]

param V > 0, integer;

var b{1..V,1..V} binary;

subject to constraint5 {i in 3..V:i mod 2=1}: b[i,i-1] = sum{j in 2..V:j mod 2=0 and j != (i-1)} b[i-1,j];

 

 

 

But I do not know how to have {1} as a union to {2, 4,..} exclude {i-1}. I need to add 1 as the only odd value. As you can see from my AMPL declaration, I do not have {1} as a union because I could not find a tutorial for it. I used V instead of N.

Please help. Thank you

[AMPL Google Group]

You can use 'by' instead of mod and use union operation. So, your constraint will be:

subject to constraint5 {i in 3..V by 2}: b[i,i-1] = sum{j in {1} union { 2..V by 2}:j != (i-1)} b[i-1,j];

--
Paras Tiwari
am...@googlegroups.com

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On Thu, May 17, 2018 at 2:38 PM UTC, Ampl Modeling Language <am...@googlegroups.com> wrote:

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[Vinh K]

Thanks Paras Tiwari. I have been trying to figure this out for weeks. I could not find any documentation on 'by'. With your help it is looking good.