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ampl

declare default value for variables in ampl

Now I have variable set x in my ampl model, and I want to define a default value for each x.

set N := 1..10;
var x {i in N} default 0;

If I build the model like this, the initial value of all x would be set as 0. How can I set different value for each x, like [0,0,0,0,0,1,1,1,1,1]?

Solution

  • If you just want to change some parts of x to a non-default value, this is easy to do. For example:

    var x{i in N} default 0;
let{i in 6..10} x[i] := 1;

    I'm not aware of any way to have more than one default value for different elements of a var.