Re: [Help-glpk] RE: Help-glpk Digest, Vol 22, Issue 12

[Michael Hennebry]

On Mon, 20 Sep 2004, Q Wu wrote:

> I'm new to learn GLPK to solve LP problem, I have a simple model for Map
> Coloring problem as below, but when I tried to solve it, I got the following
> parse error at line 12#: argument for abs has invalid type. I'm very
> confused with this error.

The phrasing is a bit confusing.
The distinction is not between integer and real,
It's between constant and not constant.
abs(linear non-constant function) >= 1 is a nonlinear constraint.

> And, I'm also wondering why strict inequality is not allowed in the model.
> Can anyone give some explanation? Thanks for any input in advance.

Open sets lead to optimization problems with no optimum solution.

-- 
Mike   address@hidden
"Nothing says it like words if you know how to use them."
                    --  the Professional Organization of English Majors