[AMPL 25071] Variable declared as Integer/ Results is fractional

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I see just one integer variable in your model:

var CVE integer >= 0;

But when I solve your problem using include Computercafee_2024_12_09.run; the value of CVE in the results is integer:

ampl: include Computercafee_2024_12_09.run;
........
Gurobi 12.0.0: optimal solution; objective 51263455.89
3121 simplex iterations
3 branching nodes
.......
ampl: option display_precision 0;
ampl: display CVE;
CVE = 4

(By setting option display_precision 0; I am asking display to use the maximum precision possible, to be sure the result value is exactly 4.)

I also get this result with Gurobi version 11, though it uses a different algorithm.

The integer variable can be relaxed by use of the .relax suffix, like this:

let CVE.relax := 1;
solve;

Then CVE has a fractional result value, and the maximal objective value is higher:

Gurobi 12.0.0: optimal solution; objective 51440779.46
5172 simplex iterations
3 branching nodes
.......
ampl: option display_precision 0;
ampl: display CVE;
CVE = 4.339090190246878

Can you post an example (including the files) where CVE is supposed to be integer, but it is fractional in the result?