Parenthesis sometimes missing

[Downsite]

Hi,

after the latest update, I sometimes get an error like this:

37  nlp_eq2.. sqr((2) * (x3) * (x3) + (-1.328171015325041) * (x3) + -2.076874228151837e-10) + sqr((+(-2.076874228151837e-10
****                                                                  $445
**** 445  More than one operator in a row. You need to use parenthesis
****        if you want to use such statements. For example
****            x := x + - not y;  ->  x := x + (- (not y));
****            sum(i$not x, ..)   ->  sum(i$(not x),..)

I assume that there is a small bug when writing from the Julia expression to the GAMS representation. Double values maybe should always have parenthesis?

[renkekuhlmann]

Oh, thanks for reporting! Will fix it right away.

[renkekuhlmann]

This should be fixed with v0.5.1. Sorry for this inconvenience! Please check if this is fixed for you and then close this issue if so - as I haven't checked your particular model.

[Downsite]

I appriciate the fast reponse!

I updated to v0.5.1 with GAMS 46.2.0, but still have the issue.

I found a simple problem that reproduces the issue, maybe you can check it out.

My current status:

Pkg.status(["JuMP","MathOptInterface","GAMS"])
Status `~/.julia/environments/v1.10/Project.toml`
  [1ca51c6a] GAMS v0.5.1
  [4076af6c] JuMP v1.20.0
  [b8f27783] MathOptInterface v1.27.1

the test problem:

 using JuMP
 using GAMS
 model2 =  Model()
 set_optimizer(model2, optimizer_with_attributes(GAMS.Optimizer, "Solver" => "Baron"))
 set_optimizer_attribute(model2, "SysDir", "/opt/gams/gams46.2_linux_x64_64_sfx")
 @variable(model2, -1.0 <= x <= 1.0)
 @variable(model2, must_have_eq, Bin, start = 0)
 @constraint(model2, con, 0 <= x^3 +  (1.0 - must_have_eq) * 100.0)
 optimize!(model2)

results for me in

24  eq1.. 0 - (power(x1, 3) + -100 * x2 + 100) =L= 0;
****                            $445
**** 445  More than one operator in a row. You need to use parenthesis
****        if you want to use such statements.

[renkekuhlmann]

Thanks, I can reproduce the issue and will add the model to the tests. Sorry for this.

[renkekuhlmann]

Fixed with v0.5.2.

[Downsite]

This fixed the issue for me, glad it was helpful to fix the issue and thanks again for the quick respones.