Segmentation fault using if-then-else with strings

[elKei24]

The following example gives me a segmentation fault:

var bool: b;
var string: s = if b then "foo" else "bar" endif;

I came across this because I have a model with some choices for the solver to make and some variables that depending on the choice do not matter any more. I do not want these irrelevant variables in my output any more, like this:

var bool: b; var 0..10: i; var 5..15: j;
output [ if b then "i=\(i)" else "j=\(j)" endif ];
solve maximize if b then i else j endif;

I guess this is not possible so far, right?

[cyderize]

var strings are not supported in any useful way currently (although indeed the if-then-else shouldn't crash, so there's a bug there).

However, since you're only looking at output, you can use fix(b) to tell the type checker that at the point of evaluation, the value of b is actually par:

var bool: b; var 0..10: i; var 5..15: j;
output [ if fix(b) then "i=\(i)" else "j=\(j)" endif ];
solve maximize if b then i else j endif;

There's also the :: output_only annotation which allows for variables which are only used during output:

var bool: b;
string: s :: output_only = if fix(b) then "foo" else "bar" endif;
output [s];

[elKei24]

@cyderize Thanks a lot, it works. Now that I knew what to search for, I also found these options in the docs.