GAMS-dev/gams.jl

Parenthesis sometimes missing

Downsite opened this issue · 6 comments

Downsite commented

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 commented

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

renkekuhlmann commented

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 commented

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 commented

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

renkekuhlmann commented

Fixed with v0.5.2.

Downsite commented

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

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